Linde Technology

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wichtiges Maß – Linksanschlagfür den grünen Kasten
Reports on Science and Technology
June 2006
Linde Technology
LeadIng.
Featured topic
“Environmental protection and sustainability”:
Papermaking with oxygen
“Green” hydrogen from algae
Other topics:
Linde AG
Abraham-Lincoln-Strasse 21
65189 Wiesbaden
Germany
Tel. +49.611.770-0
Fax +49.611.770-603
www.linde.com
ISSN-1612-2232
Fuel cells help lung patients
Synthetic fuel
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Innovative ideas and
technological competence
Catching up with Linde Technology:
Download these back issues from
www.linde.com
Linde Technology June 2006
Topics: Papermaking with oxygen | “Green”
hydrogen from algae | Fuel cells help lung patients |
Synthetic fuel
Linde Technology January 2006
Topics: Natural gas from the Barents Sea |
CO2-free coal power plant | Lift trucks in container
port | Ionic compressors
Linde Technology July 2005
Topics: Hydrogen as a driver of innovation |
Helium for research | Engineering in china
Linde Technology December 2004
Topics: Oxygen usage in steel production |
Forklift truck with fuel cell | Biotechnology for
innovative medications
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Editorial
Dear Readers,
In order that future generations can enjoy a high standard of living in an intact environment, we put a high priority
on sustainability and long-term customer benefit in developing our technologies and products. The featured articles
in this issue of Linde Technology will therefore give you an idea of our very diverse activities in environmental
protection and sustainability.
As the world’s largest supplier of hydrogen plants, we have been at the leading edge in advanced hydrogen
technologies for years. We are aware that only sustainable hydrogen production can, in the long term, enable
society to become independent of fossil fuels and limit our impact on the environment. For this reason, we
promote basic research – an example being the project to make biohydrogen from nothing but light and water,
using microalgae.
But environmental gains will not come about solely through breakthroughs in basic research. Existing production
processes must also be improved. The use of technical gases for cleaning and bleaching in the paper industry,
among others, is showing marked positive effects. This example further shows that environmental protection and
economics do not have to be opposing interests.
Economics has come to be a key topic of discussion in health care, too. Statistics show that many diseases are
growing more frequent as life expectancy gets longer. The result: massive financial burdens on health-care
systems. Our engineers have devised innovative techniques for in-home aid to lung patients, enhancing their
quality of life while cutting treatment costs.
As always, we wish you an exciting, informative time as you read this issue.
Dr.-Ing. Aldo Belloni
Member of the Executive Board of Linde AG
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Contents
6_ Hydrogen on the go: Mobile H2 filling
8_ Environment-friendly: Oxygen for paper
12_ Biohydrogen: New approaches to
station ensures flexible supply.
and pulp manufacturing.
an eco-friendly energy source.
1_ Editorial
4_ Linde News
Reports from the Linde World
Image credits: Adam Opel GmbH p.40 | Wonge Bergmann
p. 23, 23 | Corbis p.19 | Liesa Johannssen p. 7 b. | medical
picture p. 35 | m-real p. 8, 9, 10, 28 | Okapia p. 26 | Rolf
Otzipka p.5 b. | Picture Alliance p.38 | Sasol Chevron p. 41 |
Terex-Fuchs p. 29, 30, 31 | The Linde Group is in possession
of all other photographs.
Featured Topic: “Environmental Protection and Sustainability”
2
11.07.2006
8_ Green technology for white paper
Oxygen for eco-friendly papermaking
12_ The botanical fuel
Linde supports biohydrogen research
15_ “What’s the next big thing?”
Interview with Professor Hans Kistenmacher
18_ Efficient bacteria
Linde process helps clean up industrial wastewater
Environmental protection and sustainability:
Linde AG, as a worldwide company, develops
technologies for a sustainable economy so that
future generations can enjoy a high standard
of living in an intact environment.
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3
22_ Good use for CO2: New cleaning process
34_ Medical technology: Oxygen therapy
40_ Synthetic fuel: Clean diesel from
protects the environment.
in the home.
natural gas.
22_ At the sign of the penguin
Fred Butler’s German premiere
34_ Deep breathing with pure oxygen
Fuel-cell technology aids lung patients
24_ Supersonic surface enhancement
New technology joins ceramics and metals
38_ Clean sailing
Norway converts ferries to LNG
28_ A powerful drive in the sawmill
Linde hydraulic systems in the lumber industry
40_ Designer-diesel from natural gas
Linde technology for clean fuel
32_ Too valuable for the stack
CO2 Conditioning at Marl Chemical Park
Imprint
Published by: Linde AG, Wiesbaden www.linde.com
Editors: Stefan Metz, Linde AG (Editor-in-Chief); Michael Kömpf,
wissen & konzepte, Munic; Dr. Karoline Stürmer, Regensburg
Layout, lithography and production: D+K Horst Repschläger GmbH,
Wiesbaden
Translation: eurocom Translation Services GmbH, Vienna
Direct inquiries and orders to: Linde AG, Communication, P. O. Box 4020, 65030 Wiesbaden, Germany
or [email protected]
This series and other technical reports can be downloaded at www.linde.com/LindeTechnology. No part
of this publication may be reproduced or distributed electronically without the prior permission of the
publisher. Unless expressly permitted by law (and, in such instances, only when full reference is given
to the source) use of “Linde Technology” reports is not permitted without the publisher’s consent.
ISSN 1612-2232
Printed in Germany – June 2006
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Linde News
Broad-based: The BOC Group
currently employs 30,000 people in
more than 50 countries.
Linde and BOC: A perfect fit
Approval by the European Commission early in June has brought the
acquisition of The BOC Group plc by Linde AG a step closer. “We expect
the transaction to be closed on schedule in the third quarter of 2006,”
said Professor Wolfgang Reitzle, President and CEO of Linde AG. “The
extent of the commissions conditions is in line with our expectations,
and we will comply with them promptly.” The planned Linde–BOC
merger is meeting with an extraordinarily positive response in business
and media circles. The two companies complement each other in both
geographical coverage and product strategy. The newly established
enterprise will be represented in some 70 countries and hold a strong
market position in each.
Linde and BOC have been collaborators in plant construction for
some time. The U.S. joint venture Linde BOC Process Plants LLC was
founded in March 2002. Linde supplies equipment for air separation
and synthesis gas production. British partner BOC owns 30 percent of
the venture, headquartered in Tulsa, Oklahoma.
In reporting year 2005, BOC Group had sales of 4.6 billion pounds
sterling (about 6.6 billion euro). BOC has representatives in more
than 50 countries; its biggest market is the UK, followed by the U.S. The
Asia/Pacific region is another important outlet for BOC. The company
now operates through three divisions: Process Gas Solutions, Industrial
and Special Products, and BOC Edwards. This traditional British business
also has an autonomous logistics unit. Process Gas Solutions (PGS),
largest of the divisions, manufactures and sells industrial gases such
as oxygen, nitrogen and argon, as well as helium, liquefied gases and
numerous specialty gases. Its customer list is headed by major oil and
petrochemical, food and beverage, steel and glass companies. Along
with liquefied gases, the Industrial and Special Products (ISP) division
also focuses on welding and cutting gases, laboratory apparatus and
numerous medical applications. The BOC Edwards subsidiary serves the
world market with specialty gases, cleaning and polishing agents, and
apparatus and technical support for the semiconductor industry. Quite
recently it installed its first on-site fluorine production systems in Korea.
The French-headquartered Cryostar subsidiary is among the most
important fitters of liquefied natural gas (LNG) carrier ships, supplying
compressors, refrigeration pumps and turbines.
BOC traces its history back to Brin’s Oxygen Company, founded in
1886 by the brothers Arthur and Leon Brin. They produced oxygen,
Alpha Olefin plant in South Africa
Linde has received an order from Sasol Olefins and Surfactants for engineering,
procurement and construction of another Alpha Olefin plant at Secunda, South
Africa. The facility employs a novel technology for converting 1-heptene to the
versatile 1-octene. This liquid hydrocarbon serves as a chemical intermediate in
the manufacture of polymers such as polyethylene, fatty acids, solvents, plasticizers and lubricants. With a capacity of 100,000 tonnes per year, the new plant is
the sixth Alpha Olefin unit built by Linde at the Secunda refinery complex, some
130 kilometers east of Johannesburg. Mechanical completion is scheduled for
mid-April 2007. Dr. Aldo Belloni, Member of the Executive Board of Linde AG with
responsibility for the Gas and Engineering business segment, describes the special
relationship between Linde and Sasol: “This order is another confirmation of our
more than 50 years of close co-operation with Sasol.”
Years of collaboration: Sasol brought a Linde-built
Alpha Olefin plant on stream as early as 1999.
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Linde Technology June 2006
Hydrogen-powered boat on the
Alster river
chiefly for illumination, using the barium oxide process developed by
the French chemist Boussingault. The brothers located their first plant
in London’s Westminster. BOC entered world markets only after the
Second World War, and in 1946 the company opened a research and
development facility in Murray Hill, New Jersey, to develop a process
for direct oxygen injection into blast furnaces as a way of boosting
steel production. In Europe, BOC acquired Edwards High Vacuum International in 1968. BOC established a bridgehead in Japan at the end
of the 1960s, setting up the joint venture British Oxygen (Far East) in
1971. Finally, after further acquisitions and joint ventures in Taiwan,
the Philippines and Japan, the company reorganized as The BOC Group
plc in 1982. It moved its headquarters in 1985 from London to rural
Windlesham, Surrey, southwest of London. Years of expansion followed,
chiefly in east and southeast Asia, and also in Poland and the Czech
Republic after the fall of the Iron Curtain. In 1987 BOC strengthened its
U.S. presence by acquiring Selox, a regional gas manufacturer.
Hamburg runs on hydrogen: The city not only has many
hydrogen-fueled buses, but a hydrogen-powered boat
will soon ply the Alster river as well. BSU, Hamburg’s
urban development and environmental agency, has
nitiated the ZEMSHIPS project – short for “Zero-Emission
Ships”. The goal is to develop the world’s first sizable
passenger vessel powered by hydrogen and fuel cells.
Linde and BSU have partnered to bring this EU project to
life. As a founding member of the Hamburg state fuel
cell and hydrogen technology initiative, Linde has been
a major presence from the very beginning of the city’s
diverse hydrogen projects.
The idea of converting a conventional Alster vessel to
fuel-cell propulsion arose early in 2005. Linde submitted
a bid that summer to supply hydrogen. The ZEMSHIPS
Alster vessel can carry about 100 passengers and will
normally be employed as a tourist boat. The emission-free
excursion vessel will be powered by pure hydrogen
stored in on-board pressure tanks safely placed below
decks. Fuel cells combine hydrogen with atmospheric
oxygen to generate electrical energy; the output will be
around 60 kW. Plans call for a 17,000-liter liquid-hydrogen
storage tank to be erected on the shore to keep the vessel
fueled up; Linde will deliver liquid hydrogen by tanker
trucks. An ionic compressor – also developed by Linde
(see “Mobility under High Pressure”, Linde Technology,
January 2006) – compresses the hydrogen, which is then
transferred to the ship under a pressure of 350 bar.
Estimated fueling time is some 30 minutes. The results
of this project will “inaugurate a new generation of quiet,
emissions-free vessels all over Europe,” as Hamburg’s
Environmental Senator, Dr. Michael Freytag, said at the
project presentation.
Good marks from our readers
Readers of Linde Technology are very satisfied with the
publication, according to a survey sent out with the previous
issue. Participants rated the magazine on such criteria as
ease of comprehension, informativeness, range and quantitiy
of topics.
Some 64 percent of respondents spend 45 minutes or
longer reading Linde Technology, and one-third said their
copies would be read by three or more persons. Readers
especially liked the design and the information content of
the articles.
Items that caught the interest of readers above all were
those concerning the featured topic of “Energy”. Readers
awarded a good mark of 1.7 to the magazine as a whole.
The editors are grateful to all participants for their
constructive feedback.
H2 excursion boat: This zero-emission vessel will soon
be carrying tourists around the port of Hamburg.
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Linde News
Mobile hydrogen filling station
As the number of hydrogen-fueled vehicles rises, one
question comes up more and more often: Given that the
network of filling stations is still sparse, how can the
user be sure of getting the emission-free fuel? To close
this gap, engineers at Linde AG have developed a selfcontained mobile hydrogen fueling unit. The traiLH2™ can
supply vehicles – no matter where they are – with liquid
hydrogen (LH2) or compressed gaseous hydrogen (CGH2).
It carries up to 1000 liters of cryogenic (liquid) hydrogen
in a cryo-vessel; a built-in fuel cell supplies power to
the on-board network. The traiLH2™ is equipped with four
filling nozzles: the LH2 coupling developed and patented
by Linde, and three CGH2 couplings rated for pressures
from 200 to 350 bar.
The project, with major support from the state of
North Rhine-Westphalia, was presented to the public for
the first time at the end of May. Christa Thoben, Minister
of Economic Affairs for North Rhine-Westphalia, was
present as the system was demonstrated in front of the
state parliament in Düsseldorf. “The traiLH2™ is an
essential milestone for the further build-up of a hydrogen
infrastructure,” said Dr. Joachim Wolf, Executive Director
of Hydrogen Solutions with Linde Gas. Car makers and
fleet operators are showing lively interest. The mobile unit
will be in service during World Cup events and later on
at fuel-cell rallies and industrial shows.
Flexible filling: The new mobile
hydrogen filling station offers the right
nozzle for every H2 user.
Gases for Bayer plant in China
Together with its Chinese joint venture partner Shanghai
Coking & Chemical Corporation, Linde has entered into a
long-term supply contract with Bayer Polyurethane (Shanghai) Ltd. Co. Running for 15 years, the agreement covers
delivery of hydrogen and carbon monoxide as well as the
construction and operation of a plant at the Bayer Integrated
Site in the Shanghai Chemical Industry Park at Caojing, near
Shanghai. The order is worth some 60 million euros.
The principal feedstock is a synthesis gas made by
Shanghai Coking & Chemical using an environmentally safe
coal gasification process. “This production complex builds
on China’s plentiful coal reserves to produce superior raw
materials,” states Dr. Aldo Belloni, Member of the Executive
Board of Linde AG with responsibility for the Gas and
Engineering business segment. “At the same time, the
supplementary use of natural gas and LPG and redundant
process units will make the system extraordinarily flexible
and ensure security of supply.” The Bayer facility uses
hydrogen and carbon monoxide chiefly to make polyurethane
intermediates. Linde and Shanghai Coking have been working
for years on the production of hydrogen, carbon monoxide
and carbon dioxide as well as cryogenic technologies.
A first on-site plant of the same type will begin deliveries
to Bayer at Caojing by mid-2006. Bayer Polyurethane (Shanghai), Linde and Shanghai Coking have agreed to cooperate on
a future capacity expansion at the Bayer complex.
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Linde Technology June 2006
New cracking furnaces for ethylene plant
The petrochemical industry is making important contributions to
saving energy and abating pollution. For example, Ruhr Oel GmbH
has now awarded a contract to Linde for turnkey installation of five
new cracking furnaces at the Gelsenkirchen-Scholven ethylene plant.
The new equipment will replace 17 existing crackers of obsolete
design, which can no longer meet current standards for nitric oxide
(NOx) and dust emissions or energy efficiency. The five new, identical,
state-of-the-art crackers, each with a capacity of some 100,000
tonnes of ethylene per year, can handle a broad spectrum of feedstocks, from heavy hydrocarbons and naphtha to gases. Ethylene is
a key starting product chiefly for the plastics industry.
The order is worth around 130 million euros. “This project is
especially important to Linde, because it was an innovative design
concept that made it competitive,” said Dr. Aldo Belloni, Member
of the Executive Board of Linde AG with responsibility for the Gas
and Engineering business segment. “We have demonstrated our
expertise both in terms of process design as well as with an exceptional
assembly concept.” The new cracking furnaces are being built and
largely prepared for commissioning outside the plant, which
continues to operate. The existing furnaces will be dismantled during
a routine plant shutdown in September 2007. The customer, Ruhr
Oel GmbH, is a joint venture of Deutsche BP AG and Petróleos de
Venezuela S.A., the state oil company of Venezuela.
Cleaner and more efficient: New
Linde cracking furnaces greatly
reduce NOx emissions.
Second H2 filling station in Berlin
Linde AG has been collaborating with the transport operation Berliner
Verkehrsbetriebe (BVG) and the fuel company TOTAL Deutschland
GmbH for about ten years. The partners have now opened
the second public hydrogen filling station in Berlin. As part of the
European Clean Energy Partnership (CEP) demonstration project,
Linde supplied all H2 fueling, compression and storage technology
for cryogenic liquefied hydrogen (LH2) and compressed gaseous
hydrogen (CGH2) up to 350 bar. Because both cars and buses must
be served, a publicly accessible CGH2 pump was installed at the
TOTAL filling station and another pump in the adjacent BVG bus barn.
Preparations are already under way to meet future requirements
for filling of 700 bar gas storage tanks.
As part of the HyFLEET:CUTE project, BVG will put new hydrogenfueled buses on the streets beginning in June 2006. A total of 14
buses with hydrogen-powered internal combustion engines are
scheduled to be in service by 2007, giving Berlin Europe’s largest
fleet of H2-powered buses. Further plans call for the installation of a
steam reformer to make hydrogen on-site from a propane-butane
mixture (LPG).
Relying on hydrogen: German Transport Minister Wolfgang Tiefensee (left) was
joined by his French counterpart Dominique Perben for the official opening of
Berlin’s second public hydrogen filling station.
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Paper manufacturing
Oxygen for eco-friendly papermaking
Green technology for white paper
Gas-based technologies protect the environment while paper manufacturers benefit from
economical and reliable processes. With its know-how and its many patented processes,
Linde today is among the leaders in the use of gases in the pulp and paper industry. By
Bernd Müller
They are nearly a centimeter thick, they use a fair amount of
power, you can’t fold them, and they break when dropped on
the floor. Not all the advantages are on the side of computer
screens. Paper, a proven medium for over 5000 years, comes off
well by comparison: It is as thin as a breath of air, it can be stacked,
it consumes no power to display text and images, and it can be
crumpled and then smoothed flat again.
So it is no wonder that the vaunted “paperless office” never
came to pass, nor will it. Paper consumption continues to go up,
in fact: World output of office paper, newsprint and packaging
papers rose from 170 million tonnes in 1980 to 310 million tonnes
in 2000. Market researchers project a demand of around 450
million tonnes for the year 2015, with the lion’s share of the
growth occurring in Asia, especially China. But in Europe, too,
paper consumption will double between 1980 and 2015. Along
with these gains in consumption, however, come more and more
vocal calls for environmentally clean paper production. Linde has
been involved in this area since the early 1980s and is making a
vital contribution to sustainable pulp and paper manufacturing.
Papermaking used to be among the most environmentally
harmful of all industries, and not just because it was fed by
cutting down vast forests.The consumption of electricity and
water by a chemical pulp mill today is approximately 800 kWh
per tonne of pulp and approximately 30 cubic meters per tonne
of pulp. The sustainability principle applies today to forest
management, but not to that field alone: Modern pulp and paper
mills, like those in Europe and North America (and increasingly
Asia, as new mills are built there), capture and reuse nearly all
their fresh water. Spent process chemicals can now be recycled,
and organic wastes can even be used to fuel small power plants
generating electricity, steam and hot water.
Linde’s role at first was simply to supply gases and gas-based
applications for the pulp industry. In the mid-1990s the company’s
specialists foresaw a breakthrough into the paper industry,
recognizing that paper consumption and requirements on such
paper qualities as brightness and opacity would both continue
rising along with environmental protection standards. “We were
engaged with the pulp industry, and now paper became another
market of interest,” says Jörg-M. Willke, Director of Market
Development at Linde Gas. The use of oxygen, ozone and carbon
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Linde Technology June 2006
Long process chain: It takes many production steps to turn
wood into snow-white paper.
From Tree to Paper
Trees are felled by “harvesters“. These giant machines do
the job in a few minutes,
The logs are cut into sections and chipped. The wood chips
consists of cellulose, hemicelluloses, lignin and extractives
The wood chips are fed to the pulp mill
The lignin is removed during cooking and oxygen
delignification. Residual lignin and other colored substances
are removed in the bleaching steps that follows.
The bleached pulp is pumped to the paper mill (in an
integrated pulp and paper mill). In the wet end of the
paper machine, chemicals and pigments are added to
the pulp to improve the quality of the paper.
The pulp consistency (concentration) is typically 0.5-1%
of pulp in water at the inlet of the paper machine. The pulp
is dewatered in the wire section of the paper machine
and in the following press section before it enters the drying
section. The paper produced is typically wound on a roll.
dioxide makes many pulp and paper mill processes not just more
efficient but also cleaner as the gases take the place of environmentally harmful chemicals. The company’s business extends far
beyond supplying gases. “We offer our customers know-how
and patented solutions, we monitor and operate gas plants, and
we train the customer’s work force,” says Peter Hardmeier, who
is responsible for Market Development – Pulp & Paper at Linde.
Oxygen displaces chlorine
Oxygen has now become the number one gas in the paper
industry. It is a real Jack-of-all-trades because it can do several
jobs at once in the pulp mill. Since the early 1970s it has been
used to delignify and bleach pulp. Delignification is the operation
in which cellulose is separated from lignin, a natural substance
that holds the fibers together in wood. In bleaching, oxygen
has displaced harmful chemicals like chlorine. Other bleaching
agents still used in the making of white pulp are hydrogen
peroxide and chlorine dioxide. Pulp mills are increasing the use
of ozone (O3) for bleaching. Ozone is actually so effective that
it can largely replace chlorine dioxide. It is made by treating
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Paper manufacturing
Featured topic: “Environmental protection and sustainability“
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Environmentally clean process: Oxygen is now the standard bleaching
agent for the paper manufacturer M-real.
Direct supply: Linde ECOVAR®
systems produce oxygen
right where it is needed in
papermaking.
the normally diatomic oxygen molecule in an electric arc; the
product is a highly reactive gas that has a third oxygen atom in
each molecule. Ozone has found acceptance as a bleaching
agent in recent years because it is as environmentally benign
as oxygen. Although it is a strong oxidizer and an irritant in
the respiratory tract, it very quickly breaks down into the same
normal diatomic oxygen that we need to support life. This is not
so for other bleaching agents. While pulp producers in the 1970s
adopted oxygen and hydrogen peroxide – and in the 90´s ozone –
to meet increasingly stiff environmental regulations, today they
do so on grounds of efficiency: Delignification and bleaching by
no means exhaust the spectrum of uses for oxygen. It also plays
an active role in the waste-water treatment system that is an
indispensable part of today’s pulp mill. Here bacteria in activated
sludge lagoons degrade organic matter, and they need oxygen
for this purpose. Simply mixing oxygen into the waste-water
by ventilation is often not enough. Bacteria not adequately
supplied with oxygen develop an appetite for sulfur compounds,
which they convert to foul-smelling hydrogen sulfide. This gas
is noxious to people living near the waste-water treatment plant
(schoolboys used to use it in stink bombs to drive the teacher
out of the classroom). The introduction of pure oxygen blocks
hydrogen sulfide production and boosts the capacity of the
treatment system.
Oxygen has become a standard resource for the pulp
and paper firm M-real. The Finnish company, third-largest in the
industry in Europe, has made special efforts to protect the
environment in recent years. “Throughout the production chain
we look for ways to avoid harming the environment,” says
Göran Svensson, a production engineer in M-real’s pulp and paper
mill at Husum, Sweden. For example, the mill uses only oxygen
or ozone for pulp bleaching – but beyond this, it seeks the
greatest possible economy of resources in getting its oxygen.
Tanker trucks once hauled the gas hundreds of kilometers to the
site, imposing an extra burden on the environment. Today the
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Linde Technology June 2006
Bleaching
Cooking
Washing
Oxygen delignification
Washing
Bleached pulp
Waste-water
treatment
Carbon-dioxide
Waste-water
Oxygen
Wood chips
Chemical recovery
The chemical pulp mill: Wood chips go through a chemical washing and cooking process. Fibers are freed of unwanted wood
constituents, for example lignin, by several hours of “cooking” under pressure The resulting pulp is then washed and bleached.
Conditioning and recovery of the chemicals requires extensive systems engineering.
paper mill has changed over to Linde’s ECOVAR on-site supply
system, which contains standardized gas production units that
extract oxygen from the air at the place of use. The customer
does not have to worry about operating the ECOVAR plant,
because Linde built it at the mill and now monitors it remotely.
For M-real, oxygen is like water: It comes out when the tap is
turned on.
The complicated path from wood to paper
The intricate process of turning wood into paper is not as
straightforward as it might be, for customers want paper of higher
brightness. “When paper quality standards go up, it puts extra
stress on production control,” says Paper Team Specialist Hannu
Leino from the Linde Paper Team. More brightness means more
bleaching, but it is all to easy too add too much, and that affects
paper quality. And the use of environmentally cleaner chemicals
actually makes control more difficult. The most critical variable
is the pH. The amounts of acids and alkalis used in pulp and
paper manufacturing are such that pH shocks can occur if these
are not correctly metered. And then it can happen, for example,
that acid buffers such as carbonate ions in the stock are abruptly
exhausted, so the pH drops. The effect of the drop in pH is that
calcium ions react with organic substances in the stock and
precipitate out in the form of flocs, which leads to holes in the
paper or precipitation in piping and pumps. Linde paper experts
found a way out of this dilemma, designing a reactor to react
carbon dioxide with diluted sodium hydroxide. The product is a
sodium bicarbonate solution. The sodium bicarbonate solution
buffers acids such as sulfuric acid. “In this way we gain exact
control of the pH, so we can bring about optimal process
conditions,” says Leino. It turns out that the use of carbon-dioxide
buffering markedly reduces both the quantity of flocculated
calcium and – more important – its fluctuation, giving paper mill
operators the opportunity to use, for example, environmentally
cleaner bleaching agents. The patented CODIP and GRAFICO
processes have been developed by Linde in collaboration with
UPM (United Paper Mills) in Finland. The patented ADALKA
process is another application developed by Linde. More than
40 paper machines now use Linde´s solutions, mainly in the
manufacture of premium papers. Improved process control can
improve the runnability of the paper machine leading to a very
quick return on the investment. The ADALKA reactor consumes
two to five kilograms of carbon dioxide per tonne of paper, and
large mills require roughly a thousand tonnes of CO2 per year.
The carbon dioxide for papermaking is a byproduct from other
industrial processes such as the manufacture of fertilizers or
ethanol.
Of course the Linde specialists don’t mean to rest on their
laurels. They are already at work developing new ideas. For
example, the Linde BioLime process, in which residues from pulp
production are upgraded to biofuel, holds great promise for
pulp manufacturers, as Willke enthusiastically points out: “Using
this process, our customers can take a byproduct right from their
own processes and turn it into energy to run their pulp mills.”
This innovation will also improve the energy balance of the pulp
and paper industry.
Bernd Müller is a freelance technology and business journalist
in Esslingen with a special taste for innovative technologies.
Even though he wrote this article on a PC, he prefers to see his
work printed on paper.
Links for further reading:
http://spot.fho-emden.de/ut/forsch/
papierherstellung_umweltbelastung1.pdf
www.linde-gas.com
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Featured topic: “Environmental protection and sustainability“
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Hydrogen
Linde supports biohydrogen research
The botanical fuel
Hydrogens is considered to be the energy of the future, but not much research has been
done on sustainable production methods. In a Linde-supported project at the University of
Kiel, green algae and cyanobacteria are the objects of study. When light falls on these
micro-organisms, they make hydrogen from nothing more than water and carbon dioxide.
This natural production method may figure in a future hydrogen economy. By Bernd Müller
Green paradise: Professor Rüdiger Schulz-Friedrich
of the University of Kiel explores options for “green”
hydrogen production.
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Linde Technology June 2006
Basic research: From some 2000 microalgal cultures, Schulz-Friedrich’s
Green hope: Green algae and cyanobacteria may figure in
group seeks to identify the best H2 producers.
a sustainable future energy economy.
Green slime – every aquarium owner’s nightmare. But for Professor
Rüdiger Schulz-Friedrich the green algae that cause the slimy
plague are a pure blessing. The botanist has turned a greenhouse
and some climate-controlled rooms at the edge of the University
of Kiel campus into an Eden for the single-celled plants and their
cousins the cyanobacteria. Given light and the proper warmth,
they thrive splendidly. There is no free lunch, though, and in
return for their care and feeding the tiny beings must generate
hydrogen. Inside glass tanks of murky water, a gas bubbles up;
Schulz-Friedrich proves it is hydrogen by taking a fuel cell from
a child’s construction set and hooking it up to a small electric
motor with a propeller. The propeller slowly begins to turn.
“Biohydrogen from water-splitting photosynthesis is one of the
cleanest ways to produce energy,” the 45-year-old scientist
says. All it takes, he adds, is light, water, carbon dioxide from air
dissolved in the water, and a little fertilizer – just like house
plants. Nothing else.
Linde has supported the Kiel research team since 2004.
While hydrogen is considered the energy of the future, there is
as yet no easy answer how to make it commercially. Thus the
interests of Linde and those of the researchers complement
each other. “We want to generate the gas as cleanly as possible,”
says Professor Hans Kistenmacher, Director of Innovation
Management at Linde Gas and Engineering. “We take unconventional routes to reach that goal.” The route to green hydrogen,
however, is a long one – on this point Schulz-Friedrich agrees with
Dr. Hans-Jürgen Maass, an Innovation Management staffer who
has studied the potential of biohydrogen. The project is now in
the basic research phase, and commercialization is not in prospect for another decade. Maass still believes it is important
that Linde got involved early: “We are not thinking just about an
economic benefit but also about Germany as a research arena.”
Schulz-Friedrich is repeatedly reminded that the concept is not
an obvious one: “At conferences, most of my colleagues from
other countries are amazed that a company is committed to an
‘exotic’ research area like this, especially since marketing is
still years away.”
One thing is clear to Schulz-Friedrich: “One day biohydrogen
will help solve the global energy problem.” The outlook is not
bad. Free-living microorganisms produce some 200 million tonnes
of hydrogen every year. The gas is immediately consumed by
other single-celled organisms, which take up and use hydrogen
from their environment. So the researchers make a simple
argument: If microalgae can be made to generate large amounts
of hydrogen in the laboratory, it can be harvested before other
bacteria break it down. We can then view the exhaustion
of crude oil, natural gas and coal without anxiety. Hydrogen is
already being produced on a small scale in photobioreactors.
If the algae are deprived of oxygen, they use photosynthesis to
make hydrogen instead of starch. But why do they do this?
Hydrogen production as a protective measure
It used to be thought that hydrogen production by microalgae
was left over from a long-ago time when bacteria learned to
make oxyhydrogen gas as a cellular fuel. Once nature discovered
a clever light-gathering process in photosynthesis, making
hydrogen became largely pointless – but the mechanism survived.
Schulz-Friedrich postulates that Synechocystis, the cyanobacteria
in the green bottle, used the hydrogen generator to build a
subtle protective mechanism. Even robust microalgae often suffer
light stress, for example in shallow coastal waters where waves
act like a magnifying glass to concentrate sunlight to many times
its normal strength. The intense light activates the complex
photosynthesis machine so much that it would quickly be overtaxed and damaged. The bacterium therefore uses the enzyme
hydrogenase to convert the excess energy into hydrogen, which
escapes as if through a safety valve.
In a milk-bottle-sized laboratory culture, single-celled green
algae or cyanobacteria produce at best three milliliters of hydrogen per hour, transforming about 0.1 percent of incident solar
energy into the gas. Microalgae can live with this, but Rüdiger
Schulz-Friedrich can’t: He would like to boost the yield a hundredfold. For biohydrogen to be economical, the U.S. Department of
Energy calculates, the microalgae will have to convert five to ten
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Hydrogen
Hydrogen production with the aid of sunlight
5
Photosynthesis
+ Hydrogenase
Bioreactor containing algae or cyanobacteria
2H2O
Hydrogen
-O2
2H2
Light-absorbing dyes in the algal cells enable them to use sunlight, water and carbon
dioxide and generate oxygen and sugar. The sugar is then converted to starch or biomass. If the organisms are deprived of oxygen, they use the radiant energy to make
the desired product, hydrogen, instead.
percent of radiant energy to hydrogen. Researchers have
nudged the efficiency up to two percent, but only at very low
light intensities: 20 watts per square meter. Although sunlight
in Europe is ten times brighter, the microalgae cannot turn the
extra energy into hydrogen. This will have to change.
The chief tool the researchers will use is genetic engineering.
The team at Kiel is, however, pursuing other strategies, such
as searching for natural producers. “We are now in the huntergatherer phase,” says the professor. The Kiel botanists will
spend the next two years sorting through a collection of 2000
microalgal cultures to find the best hydrogen makers, then try
to optimize these by genetic modification. To this end, the team
(together with the Competence Center for Biomass Utilization)
has applied for a grant from the state of Schleswig-Holstein,
which supports 20 working groups in a variety of areas. SchulzFriedrich hopes to profit from the results of his colleagues. Direct
harvesting of hydrogen, the technique he is working on, is just
one possible approach. Another is to produce biomass first and
then extract the valuable gas from it in a bioreactor. Biomass
is normally a source of frustration for the Kiel group, because
every quantum of energy the bacteria use for their own growth
is a quantum they do not employ in making hydrogen.
Hopes invested in “green” hydrogen
The Kiel biologists have recently been doing systematic studies
to find the conditions under which microalgae are active in the
right way. A minireactor supports a pair of two-liter algal cultures,
while a complicated apparatus performs measurements right in
the liquid and records how pH, temperature and the outputs of
hydrogen and oxygen vary. Fluorescence, a measure of photosynthetic efficiency in the cell, is a key parameter. The point of
this effort is to determine more exactly what reactions are taking
place in the cell. Scientists know that the metals nickel and iron
play important roles in hydrogenases; an enzyme with iron alone
is much more active and produces correspondingly more hydro-
gen, but it is very sensitive to oxygen. Researchers all over the
world are therefore seeking strategies to block destructive
oxygen. American biologists for example are trying to restrict
the transport of molecular oxygen; the Kiel group is exploring
the use of additional chemical bonds to immunize the metal
center against oxygen attack.
Schulz-Friedrich has noted at several conferences – most
recently an International Energy Agency meeting this February
in Bangkok – that the topic of biohydrogen is attracting international interest. The U.S.A., in its effort to become more independent of crude oil, has invested great hopes in green hydrogen
production. The U.S. Air Force alone is supporting five projects
with an eye to securing fuel supplies for its airplanes when oil
supplies run out in a few decades. Since the 1990s, Japan has
had plans for huge farms where kilometer-long transparent
tubes floating in the sea will confine microalgae, exposing them
to sunlight so that they generate hydrogen. The concept seems
to work in small installations, but the yield is not high enough to
justify industrialization.
Even though the project is at an early stage, Linde has an
eye on the long term. “If we are still to be able to drive our
cars when coal and oil have grown scarce,” says Kistenmacher,
“now is the time when we must concern ourselves with finding
new approaches to generating energy.” Linde’s commitment to
hydrogen production by algae puts the company in the forefront
of this effort.
Bernd Müller is a freelance journalist in Esslingen.
Writing for scientific and business media, he specializes
in innovative technologies.
Links for further reading:
www.uni-kiel.de/botanik (only in German)
e15_Kistenmacher
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Interview
Linde Technology June 2006
15
Idea manager: Professor Hans Kistenmacher is
director of the Innovation Management unit of
Linde Gas and Engineering.
Interview with Professor Hans Kistenmacher – Innovation and Sustainability
“What’s the next big thing?”
Professor Hans Kistenmacher has been Director of the Innovation Management unit of
Linde Gas and Engineering since April 2005. His main tasks are to identify trends, find solutions,
and open new markets with new products. In an interview with Linde Technology he explains
how the creative ideas of Linde engineers can contribute to sustainable success.
The German word “Nachhaltigkeit”, meaning sustainability,
has already become sort of a buzzword. What does the term
mean to you?
Because I lived in the U.S. for a long time, sustainability is more
familiar to me, and I don’t think Nachhaltigkeit is a very apt
translation. Sustainability includes both surviving into the future
and maintaining quality of life. If you understand the word
this way, it means we must examine every area of our life and
business and ask ourselves what we – Linde AG – can contribute
to identifying future topics of concern and solving urgent problems that may arise. After all, Linde views itself as a “Solutions
Company.” This in the final analysis is why the Linde Gas and
Engineering Innovation Management unit was established.
As its director, you have the goal of making sure the Gas
and Engineering division will remain competitive in a
sustainable way. In concrete terms, what does that mean?
We will pick up market trends that will enable Linde to continue
its profitable growth and leadership. We’ll be concerned with
trends that might not get the proper attention in the day-today life of a large corporation. Our thinking will touch on many
subjects, including some that Linde – for a great variety of
reasons – has never thought about.
What trends have you identified in your work so far?
Our Innovation Board, composed of selected Linde Gas and
Engineering managers, has stated goals and strategies for
Innovation Management. There are five points of concentration:
energy, lifestyle, information technologies, new technologies
and consumer markets. So we are taking in many areas where
our company will be facing a very fundamental change in the
coming years. In short, we continually ask ourselves, “What’s
the next big thing?”
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Interview
And how do you implement this knowledge in sustainable
business practices?
Let’s consider energy as an example. What will power our cars
20 years from now? What will drive our machines? Gas and oil
are becoming more and more scarce and expensive. How can
industry respond? Our entire system for getting raw materials
will change. We have to make an early start toward finding
novel energy sources on the one hand; on the other, we must
find ways to save energy in industrial processes and optimize
our equipment in terms of energy efficiency.
Where do you see the opportunities?
A good example is our air separators. We are the world market
leader in this technology. Our large plants produce more than
3000 tonnes of oxygen a day; that corresponds to around 100
tank cars of liquid oxygen. Running these plants takes several
tens of megawatts; reducing energy consumption just a few
percentage points would therefore have a substantial effect on
their life cycle cost. So we are studying all the opportunities that
modern information technology offers, not least the availability
of more and more powerful computers.
On the other hand, since early 2005 we have been marketing
small, portable oxygen generators for home use, such as in
long-term oxygen therapy. These generate just 0.5 liter of oxygen
per minute. But these devices employ an environmentally and
economically sustainable technology that helps reduce the
significant energy costs to the end user. We use a modern fuel
cell to recover about 50 percent of the energy needed [Editor’s
Note: See also the article “Deep Breathing with Pure Oxygen”
on page 34 of this issue]. So the question is, how do we generate
oxygen, or hydrogen for that matter, in the most economical and
environmentally friendly way.
Since you brought up hydrogen: This gas will become a
sustainable energy source only when it no longer has to
be made from fossil fuels. What efforts is Linde making
in this direction?
A special Hydrogen Solutions department is working to develop
infrastructure, storage and filling technology to make hydrogen an
environmentally safe energy source. In Innovation Management
we are also exploring new and unconventional approaches
to generating hydrogen. We are now deeply involved with CO2-
neutral “biohydrogen” technologies. In the next two years, the
time needed to set up the planned hydrogen liquefaction plant
at Leuna, we will build a facility there to produce hydrogen
exclusively from renewable feedstocks. This process will both
make hydrogen in an absolutely CO2-neutral way and permit
emissions-free vehicle engines using either fuel cells or the
internal combustion engine. In this second connection we are
working with a renowned automaker to bring about a drastic
increase in the efficiency of the hydrogen-fuelled internal
combustion engine, which has always been poor. So we are
combining innovation with sustainability – environmentalism
with economy.
Biomass plays a more and more important role in the
sustainable energy economy. What opportunities do you
see for Linde in this field?
Renewable raw materials are far more complex mixtures than
the hydrocarbon compounds we have been using in engines
and power plants. Biodiesel production, for example, generates
wastes that merit closer analysis. At present we are studying
whether these wastes can also be turned into a hydrogen source.
The CO2-neutral hydrogen process in the Leuna plant may be
powered by such a biodiesel waste product. But we are also
looking at a range of other biomass sources, from shredded
vegetation and straw to wood and wood chips. Experts at LindeKCA-Dresden in Germany are also seeking to learn what waste
streams must be blended – and how – in order to maximize the
yield of biogas for downstream hydrogen production. We are the
European market leader in biogas from waste, with numerous
large plants already built. We also have many years’ experience
in using clarifiers to separate biomass. Linde Engineering, for
example, has constructed large clarifier systems for many major
U.S. cities; our plants are treating wastewater in Los Angeles,
Miami, Boston and San Francisco. Thanks to a Linde plant, the
water of Los Angeles’ Santa Monica Bay is now cleaner than it
was when Europeans arrived in California.
You cited “new technologies” as an area of concentration.
What projects are under way here?
One is the development of an ionic compressor, which uses
ionic liquids – salts that are liquid at room temperature [Editor’s
Note: see also Linde Technology, January 2006]. Because
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“We are a ‘solutions
company’”
Professor Hans Kistenmacher
compression takes place at a constant temperature, this machine
transforms input electrical energy to energy of compression
in a thermodynamically ideal way. For natural gas and hydrogen
filling stations, this new technology not only slashes maintenance
costs but also saves a considerable part of the energy needed
to compress the fuels. What is more, ionic liquids, which had not
been studied closely until the last few years, will enable us to
get into very important energy-saving applications in our core
business areas, gas separation and storage.
Another focal area for Innovation Management is lifestyle.
Is Linde now becoming a lifestyle company?
Not at all. But people, fortunately, are growing older and older,
and the resulting requirements and consequences call for new
approaches. We are now studying, for example, how oxygen can
help protect our health and how we can use it prophylactically.
And this comes back to my definition of sustainability, because
we are seeking to maintain quality of life. This market segment,
known as LOHAS – Lifestyle of Health and Sustainability – in the
U.S., is growing very rapidly. We are implementing ideas and
projects that will get us into the chain of value creation, where
Linde has had little or no involvement in the past. We are prepared
to take calculated risks provided we get the expected return on
our investment.
have been of great relevance to daily life. The first German
Fred Butler® shop, in Frankfurt, opened to the public in May. The
Fred Butler process has the unique feature that the conventional
dry-cleaning solvent perchloroethylene, which is not without
its hazards, is replaced by liquid carbon dioxide. The CO2 is a
byproduct from industrial and chemical processes and would
otherwise be released unused into the atmosphere. We recycle
a greenhouse gas, in other words, and make it replace a
suspected carcinogen. At the same time, the garments being
cleaned get gentler treatment and feel good against the skin
after cleaning. This technology has been thoroughly tested
[Editor’s Note: see the article “Deep cleaning with carbon
dioxide,” Linde Technology, July 2005], and Linde’s Fred Butler
subsidiary is now franchising it in key western European countries.
Where do you personally see further fields of activity
where innovation and sustainability can be combined?
Power generation and individual transportation, as I see it, hold
immense potential for creative, environmentally meaningful
ideas and projects. A lot could still be done in this area to save
energy and reduce environmental impacts – to our benefit and
that of generations to come.
The interview was conducted by Stefan Metz
and Michael Kömpf.
You also listed consumer markets. Where is Linde
concentrating in this area?
Last year and this year, our activities in chemical textile cleaning
Profile:
Professor Hans Kistenmacher has directed the Innovation Management
unit of Linde Gas and Engineering since April 2005. He previously
worked for more than ten years in the U.S., serving most recently as
Executive Vice President of Linde BOC Process Plants LLC. He began his
career with Linde in 1974 in the Engineering and Contracting Division.
Since 1992 he has also been an honorary professor in Computer
Aided Chemical Engineering at the Technical University of Munich.
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Wastewater treatment
Featured topic: “Environmental protection and sustainability“
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11.07.2006
Linde process helps clean up industrial wastewater
Efficient bacteria
Wastewaters from chemical and petrochemical plants require thorough cleaning before
they can be released into streams. Linde oxygen is now helping bacteria in the treatment
system at Shell Deutschland Oil near Cologne perform their job even more efficiently. The
process not only protects the environment but also saves money. By Katharina Becker
Not many decades ago the Rhine was the most romantic sewer
in Europe. In many places, untreated wastes from millions of
residents and from chemical and industrial plants had turned
Germany’s mightiest river into a poisonous cesspool. The salmon,
most emblematic of all Rhine fish, died out in the mid-1950s.
Soon the declining oxygen content made things hard for even
the most accomplished survival artists. Rafts of foam piled up so
high that they blocked the view from bank to bank along the
1320-kilometer stream. Then November 1986 brought catastrophe,
as an accident at the Sandoz chemical plant in Basel sent fish
floating belly-up for many kilometers downstream. It was a turning point for public awareness – and politics. Just a year later
the countries lining the Rhine’s banks resolved to reintroduce the
salmon as a swimming demonstration of a functional ecosystem.
A lot of water has flowed down the Rhine since then, but not
untreated. Strict laws, communal sewage treatment plants and
large investments in industrial wastewater cleanup have brought
the river back from the brink of death. Levels of harmful pollutants
are down by 70 to 100 percent, dioxins are below detectable
levels, and heavy metals have been greatly reduced. Although
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Environment and technology: Linde’s SOLVOX® technology gets wastewater so clean that it exits
the Shell Deutschland Oil refinery cleaner than the water in the Rhine itself.
nitrogen compounds of agricultural origin, pharmaceutical
residues and hormones are still entering the Rhine, today the
salmon is just one of the many fish species that have come back.
Wastewater cleaner than the Rhine itself
Even Shell Deutschland Oil GmbH, at its Godorf refinery near
Cologne, must observe stringent requirements as it releases
wastewater into the Rhine. Using an oxygenation system built
by Linde, the refinery now renders cooling water and process
wastewater cleaner than the standards demand. “The water we
discharge into the Rhine is cleaner than the water in the Rhine
itself,” says Shell engineer Steffen Eggers.
Wastewaters arising from gasoline, kerosene and diesel
refining unavoidably contain a wide variety of pollutants. Along
with oils and hydrocarbons, these include large amounts of
ammonium; ammonium is also present in fertilizers, as are nitrates.
These substances would accelerate the growth of algae, cause
the collapse of aquatic ecosystems, and thus lead to fish kills.
They must be entirely removed from water before it is released
into the river if such collapses are to be prevented. Shell’s regulatory permit allows the discharge of up to 260 cubic meters
of wastewater per hour into the Rhine. Government inspectors
make regular checks to determine whether, say, all nitrogen in
the form of nitrate and ammonium compounds has been removed
from the water.
Elixir of Life: Water has always been the wellspring
of life. The wonderful wet stuff covers most of the
Earth’s surface. But only three percent of all water is
fresh, and most of this is locked up as ice in the polar
caps. Just one percent of the world’s fresh water is
available for use – not much in view of the global
population explosion and steadily rising water consumption. Scientists estimate that every sixth person
on Earth lacks access to clean water.
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Wastewater treatment
Oxygen tank
Evaporator
Oxygen
control unit
Oxygen pipe
Oxygen
feeding valves
Aeration tank
Wastewater influent
Effluent
Diffuser mats
Oxygenated water: This simplified drawing illustrates the principle of the SOLVOX® process. Oxygen injected at
the bottom of the basin helps bacteria, like those at Godorf, clean up wastewater more effectively.
The nitrogen removal process is a lengthy one. To begin
with, the wastewater goes through a treatment stage in which
the major contaminants are separated. Oil and other species
form precipitates (flocs) when treated with special chemicals. A
flotation stage follows; compressed air admitted to the bottom
of the clarifier rises in the form of tiny bubbles, collecting
the flocs and carrying them to the surface. There the product is
skimmed off, concentrated and sent to disposal.
Water Quality in Germany: More than 95 percent of
Germany’s population are served by public sewer systems.
The sewer network is about 450,000 kilometers long,
enough to stretch around the Earth eleven times.
More than 10,000 sewage treatment plants treat 9.6
billion cubic meters of wastewater a year. The number
of systems using biological treatment has increased
steadily to a figure of some 96 percent today. Since
1976, industry and manufacturing have been subject
to more and more stringent water pollution standards.
Treatment and other voluntary practices have markedly
enhanced the quality of water in rivers, smaller streams
and lakes.
Bacteria as purification tower
The pretreated waste next passes on to a classical biological
treatment system. It comprises a series of three activated-sludge
tanks with a total capacity of 4280 cubic meters. Some 90 percent
of pollutants are removed in the first, largest basin. “What we
really have here is a copy of nature in a very narrow compass,”
explains Volker Knab, project coordinator for Linde Gas. What
he means is that protozoans (rotifers, vorticella, etc.) and other
microorganisms do in the tanks exactly what they would do in
the natural world: clean up the water. But even bacteria are
creatures of habit. They do not like sudden changes such as
fluctuations in flow rate and variations in composition. “The
clarifier is like a bottleneck that can stop the entire plant,” says
Knab, “so it is important that the biological process runs along
as smoothly as possible.” To keep things steady, the clarifier has
a buffer tank that can temporarily hold up wastewater surges.
Nitrogen is eliminated in two steps. In the first, called
“nitrification,” bacteria oxidize ammonium to nitrate. “They need
lots of oxygen for the purpose,” explains Knab, “just as they do
to degrade hydrocarbons.” Oxygen used to be brought into the
tank by a surface aerator, with pump rotors that drew in water
and accelerated it through the air, giving it a chance to absorb
oxygen. This system, however, did not give satisfactory results.
Not only did the spray of wastewater contaminate walkways and
the clarifier, creating an occupational safety problem, but “this
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Linde Technology June 2006
Effective bacteria: Microscopic life forms in the Godorf treatment plant of Shell Deutschland Oil
clean up some 4320 cubic meters of wastewater per day.
method was incapable of removing nitrogen from the water,”
Knab says. To say nothing of the odor. Shell Deutschland therefore came to Linde AG in 2001 asking for a more effective
solution to be found. The three clarifier tanks at Godorf were
all converted from surface aeration to bottom aeration at the
same time in November 2002; the job took just two weeks.
Making this change meant that Shell did not have to expand the
system or make more extensive changes to it. “With our SOLVOX®
process,” reports Knab, “treatment capacity can be boosted
quickly, in a simple way, without costly reconstruction. Today we
can actually remove 98 percent of the nitrogen from the water.”
Building a new plant would have cost Shell some four million
euro.
4320 cubic meters of clean effluent per day
Even so, the shape of the first clarifier tank and the extremely
high nitrogen loading prevented the standard system from yielding optimal results. “The pollutant burden in this tank got in the
way of enriching the water with enough oxygen,” explains Knab.
Conditions were not ideal, and the microorganisms could not
work at full speed. A solution was devised for this problem too:
“In place of the SOLVOX® units, we put in twelve special six-jet
ejectors. These distribute oxygen in fine bubbles in order to get
the highest possible oxygen utilization.” From nozzles on the
bottom of the tank, a mixture of water and oxygen now flows
through the wastewater, establishing optimal living conditions
for the bacteria and at the same time blocking the formation of
deposits that would be difficult and costly to remove. In the end,
the success of the approach led to the development of a new
standard series under the name SOLVOX®-V. The waste is oxygenated for 40 minutes in the nitrification stage. The next stage of
nitrogen removal is called “denitrification.” The Shell treatment
plant operators now turn off the oxygen for 20 minutes and add
methanol to the waste in its place. Lacking oxygen, the bacteria
utilize oxygen from the nitrate produced in the first step, converting the methanol to carbon dioxide and water. The product is
elemental nitrogen, which exits the process as a gas. In this way
the three activated-sludge tanks treat an average of 4320 cubic
meters of waste per day.
The conversion by Linde experts brought many advantages
to Shell: Not only is wastewater treatment effectiveness up, but
odor pollution is substantially down. Savings with the low-maintenance system more than offset the costs of supplying oxygen.
“On the bottom line, it’s a big plus for the operator,” says Knab.
Today Godorf’s 46-year-old plant is among the most advanced
and powerful in Germany. Since it was brought on stream, oxygen resupply has also been automated: The level in the oxygen
tank is electronically reported to Linde so that a delivery can
be initiated when needed. “Our experience is that this system is
worthwhile mainly for industrial treatment plants,” Knab explains.
“Here, as a rule, wastewaters are more heavily contaminated
and much warmer than in municipal plants. These extreme
conditions give the oxygenation system a chance to display its
advantages to the full.” Not just in favor of water quality in the
Rhine.
Katharina Becker is a freelance business journalist based in
Frankfurt am Main. She writes for, among other outlets, the
AFP wire service and a variety of newspapers and magazines.
Links for further reading:
www.linde-gas.com
www.linde.com
www.shell.com
www.iksr.org
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Dry cleaning
Fred Butler’s German premiere
At the sign of the penguin
Fred Butler®, a subsidiary of Linde AG, is marketing a new process for eco-friendly
textile cleaning. Recycled carbon dioxide from industry replaces aggressive conventional
substances and cleans even tricky materials such as leather, fur and down. The first Fred
Butler® shops have now opened in Germany too.
Convenient service: Fred Butler®’s novel B-to-C concept includes
a special pickup and delivery service for professionals.
Clean air: Staff and customers of Fred Butler® shops do not have to
suffer the nuisance of “perc” thanks to the novel cleaning process.
The time is past when a dry cleaner’s shop in a residential area
could be spotted from far off by the odor. It was not just people
with sensitive noses who were bothered by the smell of chlorinecontaining solvents – some suspected of causing cancer. The chief
offender was the commonly used solvent perchloroethylene,
called “perc” for short, which made many dry-cleaning workers
ill. Help is on the way in the form of a novel process that uses no
bad-smelling chlorine compounds at all [Editor’s Note: see the
article “Deep cleaning with carbon dioxide,” Linde Technology,
July 2005]. In their place, byproduct carbon dioxide from industrial processes is recycled and used for cleaning.
Fred Butler® is the Linde AG subsidiary that franchises the new
technology in key western European countries. This innovative
business-to-consumer concept represents an expansion of the
typical Linde investment goods business. The novel technology
is now available to German customers for the first time. A grand
opening ceremony for the first German shop took place on May
17 in Frankfurt am Main, and among the speakers at the event
was Andreas Klensch, Managing Director and CEO of the Fred
Butler® Group. Klensch stated, “The Fred Butler® enterprise stands
for a new generation of textile cleaning, which seeks to benefit
both human beings and the environment by offering a real
alternative to conventional methods.” Under the sign of the
friendly penguin that adorns the Fred Butler® logo, several drycleaning companies in the Netherlands, Denmark and Sweden
already rely on the technology. A closed cycle makes the cleaning
process CO2-neutral. The method has already been recognized
by several organizations, including the European Union and the
Swedish Center for Pollution Prevention. The process has also
received the coveted Nordic Swan ecolabel (comparable to
Germany’s Blue Angel) from the Council of Nordic Ministers,
designating it as exemplary in terms of environmental and
consumer protection.
Easy on garments, easy on the environment
For decades, the American aerospace industry has used liquid
carbon dioxide to clean delicate instruments and for other
purposes. The first application of the principle to textiles also
took place in the U.S. in the mid-1990s. Dirty clothes are placed
in a sealable, drum-shaped cleaning chamber from which the air
is evacuated. Next, CO2 gas is admitted until the pressure is over
50 bar, about twenty times as high as the pressure in an automobile tire. Liquid CO2 is added along with a small amount
of biodegradable surfactants, and the washing process begins.
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Linde Technology June 2006
High pressure in the
cleaning chamber
CLEAN DRY CLEANING
23
Cleaning chamber
Low temperature
gentle to fibers
and colors
Drainage for
dirt particles
CO2-storage
vessel
Distillation unit
Compressor
Cooling unit
Novel natural cleaning using CO2
Fluid carbon dioxide which accumulates in
industrial poduction processes is used to
clean textiles and is both kind to the skin and
environmentally friendly. Textile cleaning is
carried out in cleaning machines specially
developed for this method:
• The carbon dioxide is cleaned and
processed in special plants.
• Tankers bring the gas to centrally sited
Fred Butler cleaning facilities, where it is
stored in large tanks.
• In the actual cleaning process the gas is
liquefied under pressure and introduced
into the washing chamber of the CO2
washing machine. Afterwards, biologically
degradable substances are added.
• The liquid CO2 penetrates deep into the
fibres and dissolves fat, oil and other
dirt particles. Demanding materials such
as leather, down duvets and furs can
be gently cleaned using the innovative
method.
Rotating the drum makes the liquid carbon dioxide penetrate
deep into the fibers, fixing grease, oil and dirt particles and
gently lifting them out. When washing is complete, the CO2 is
distilled by allowing the liquid carbon dioxide to revert slowly to
the gaseous state. This step separates the impurities. Now the
pressure in the cleaning chamber is lowered, and the door can
be opened. Only a little – about two percent – of the gas used
escapes into the atmosphere, while 98 percent can be used for
future cleaning cycles.
It is not just the environment that gains from the new process.
There are also advantages for the garments, which come out
clean, free of gray film, and have a pleasantly soft feel. Because
cleaning takes place at low temperatures, only five to 15 degrees
Celsius, colors stay bright and fibers remain unharmed. Experts
estimate that garment life is lengthened by 30 to 40 percent. A
further plus for CO2 cleaning is that it works on leather, silk and
furs as well as stuffed animals and down comforters – materials
and products for which chemical cleaning has not been advisable
before.
Fred Butler® means to set a new standard not just environmentally, but also in terms of service. Its inviting shops are easily
accessible in city centers and shopping malls, and it has kiosks
in big department stores. The actual cleaning takes place in
central plants. Fred Butler® office pickup and delivery service
is a convenient alternative chiefly for professionals. In the
business-to-business sector, the company offers its services to
establishments like hospitals and institutional kitchens that
generate large volumes of laundry on a regular schedule. By
the end of 2006, Germany will have three cleaning plants, 10
franchise shops and 100 company drop-stores.
• After each wash cycle, the
impurities are separated and discharged
by distilling CO2.
• With the aid of a compressor and a
cooling unit, the distilled CO2, now in
a gaseous state, is re-liquefied.
• 98 percent of the CO2 is stored in the
storage vessel to be used again.
• The pressure generated in the cleaning
chamber is lowered and the door can
be opened.
Clean garments: Treatment with CO2 in wash drums removes grease,
oil and dirt from garments in an average of 35 minutes.
Links for further reading:
www.fred-butler.com
www.linde.com
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Thermal spraying
New technology joins ceramics and metals
Supersonic surface enhancement
Now ready for market rollout is a technology developed by Linde engineers for
enhancing the surface of almost any material with tough, durable metals. The method
protects chemical tanks against corrosion, heals cracks in automotive engines and even
renders an artificial hip joint more biocompatible. By Michael Kömpf
Surface treatment: In the cold spray method,
tiny metal particles are impelled toward a surface
at supersonic velocities, combining with the substrate
material to form an ultra-thin coating with special
properties.
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Linde Technology June 2006
Workpiece
Carrier gas and
De Laval nozzle
metal powder
Gas and metal particles
at supersonic speed
Process gas
Supersonic powder: In the special De Laval nozzle, gas and metal particles are accelerated to speeds
as high as 1200 meters per second before they impact on the workpiece being coated.
Pretty soon, orthopedists and engineers designing chemical
tanks will have something to talk about together. These two
professional groups seem at first glance not to have much in
common, but they are now linked by a novel processing technology for titanium and tantalum. The properties of the lustrous,
graphite-gray metals are highly prized by doctors who do hipreplacement and other prosthetic surgery, but also by engineers
concerned with protecting chemical apparatus and tanks from
attack by highly aggressive media. So what is the common factor
in chemical vessels and artificial hip joints?
It’s a special surface enhancement technique called the
cold spray method. “The method makes it possible to coat any
material with almost any metal,” explains Peter Heinrich, Director
of Thermal Spraying at the Linde Development Center in Unterschleissheim, a Munich suburb. Thermal spraying is an umbrella
term for a range of coating methods including cold spraying. These
processes, in industrial service for 100 years or so, are used
when a component or product needs a metal coating; examples
are heat-conducting cladding on the bottoms of cooking pots,
anticorrosion coatings on bolts and decorative patterns on glassware. In thermal spraying, a gas flame, a laser beam or an electric
arc melts a metal, which is then accelerated toward the substrate
(the surface to be coated) under high pressure generated by a
stream of gas. The coatings that result can perform a great variety
of special functions. Heinrich, one of the fathers of the new
technology, continues, “We can use cold spraying to make surfaces
that are extra-stable to certain chemicals, electrically conductive,
and so forth.”
Surfaces with extreme strength
“Cold spraying produces a true positive connection in which the
molecules of the two materials are actually welded together,”
Heinrich explains. The technology behind the method is ingenious:
A gas, usually nitrogen, is accelerated to a supersonic speed in a
specially modified De Laval nozzle. Linde engineers feed a metal
powder into this stream, and the gas accelerates it out of the
nozzle at high velocity. When tiny particles of metal moving faster
than a threshold speed impact on a surface, they form a tight,
adherent coating that is welded to the substrate on a microscopic
scale. “Individual powder grains are squashed almost flat, like a
bullet hitting a steel plate, and embedded in the parent material,”
explains Heinrich. In this way it is possible to make extremely
strong and extraordinarily dense coatings. Preheating the gas jet
to temperatures between 300 and 600 degrees Celsius not only
boosts the flow velocity and thus the particle velocity, but also
warms the particles in such a way as to improve their adhesion
on impact. The spectrum of sprayable metals extends from zinc,
which has a relatively low melting point, to niobium, which has
a high one.
Auto industry shows interest
The cold spray method gets its name because, in contrast to
conventional thermal spraying, the gas temperature remains well
below the melting point of the coating material. Undesirable
effects such as oxidation, which often cause problems in other
spray processes, thus do not occur. “This advantage over all
conventional thermal spraying methods – even modern highvelocity flame spraying – has a positive effect on the properties
of the sprayed metal coating, one example being the electrical
conductivity of the composite,” states Werner Krömmer, another
staff member working on cold spraying at the Linde Development Center.
Linde engineers typically run the cold spray process with 10
to 40 micrometer powders but, adds Krömmer, “we have also
sprayed powders with particle sizes up to 200 micrometers.” This
is an important point, because powders are cheaper to produce
– and hence the entire cold spray method is more economical –
the larger the grain size. Another factor helping to reduce costs
is the use of nitrogen to transport the powder particles. “It takes
about 90 cubic meters of gas per hour,” says Krömmer, “and until
recently helium was the only gas that could be used to work
with many metals. That was expensive.” What enabled the Linde
engineers to dispense with helium almost altogether was the
development of a special nozzle.
25
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Thermal spraying
Cost reductions in health care
When applying sprayed tantalum coatings, health-care professionals not only look for low costs but also special surface
properties. It is desirable if an implanted artificial hip joint can
bear load promptly, so that the patient can get up and walk after
a short time; for this to happen, the bone must bond well to the
implant. Bone cement is often used to seat the new joint firmly
in the bone, but the bond may fail, and in such cases the patient
suffers pain and under some circumstances may hardly be able
to move. The increasingly common practice is therefore to insert
the implant directly into the bone, thus producing a much stronger
and more durable bond. The joint is usually made of titanium,
which is additionally coated with titanium powder so that bone
cells can colonize the porous surface and bond to the metal
coating. Because titanium is costly, however, orthopedists are
continually looking for a less expensive substrate material. Such
a material would have to be coatable with titanium, and Linde
technology now offers a possibility: “With cold spraying, we can
design composites in which the parent material is just as stable
as titanium but comes at a fraction of its cost,” says Heinrich.
“Coating this material with titanium would then bring about the
same favorable conditions for bone-cell adhesion.” Some
250,000 knee and hip replacement surgeries take place every
year in Germany alone, so such a technique could mean a
major economy in health care – and statisticians project that
the figure will triple in the next ten years!
Medical technology: With the cold spray method, inexpensive
implant materials for such applications as artificial hip joints can
be given porous surfaces readily colonized by bone cells.
Heat removal: Thin copper films on heat sinks for PC
fans ensure quick removal of heat.
Born under an accidental star
When tantalum is used in the construction of chemical tanks,
the aim is just the opposite of what is needed in the orthopedic
application. Here the “surroundings” must not bond to the metal.
The metal coating must be extremely stable when aggressive
acids are stored in large tanks or mixed with other chemicals.
Krömmer says, “The usual way to protect the insides of large
vessels is with a liner of tantalum plates several millimeters
thick. It does protect against corrosion, but it is costly.” Cold
spraying enables Linde engineers to apply a coating to a cheaper
substrate material and achieve the same stability afforded by
the thick plates. “We now think the cold spray method will let
us cut costs by a factor of four,” Krömmer declares.
The birth of cold spraying dates back to the mid-1980s, and
– as it does so often – accident played a key role. A program
at the Institute for Theoretical and Applied Mechanics, operated
at Novosibirsk by the Russian Academy of Sciences, featured
experiments in which powder grains were accelerated in a
supersonic wind tunnel. The real objective was to analyze the
effect of erosion on missiles in flight. Professor Anatolii Papyrin’s
team of scientists instead made an astonishing discovery: At
particle velocities greater than a certain value, the particles no
longer erode the surface but adhere to it, and adhere strongly.
Papyrin later emigrated to the U.S., where he continued this work
and developed the cold spray method. At a 1995 conference in
the U.S., he met Peter Heinrich and Professor Heinrich Kreye, of
the Helmut Schmidt University in Hamburg. Heinrich and Kreye
immediately became excited about the potential of the new
technology; somewhat later they obtained the needed licenses
and established a “Cold Spray Competence Group,” where Linde
collaborated with the German Armed Forces University to further
the technology. While the university was interested chiefly
in scientific topics, Linde focused above all on such practical
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Linde Technology June 2006
aspects as the development of hardware. “We built, for example,
the prototype of the gas heating system that raises the process
gas to the desired temperature,” Krömmer recounts.
Within a few years, the competence group – together with
Cold Gas Technology GmbH (CGT), an independent enterprise
founded late in 2000 – systematically brought the technology to
a marketable level. Linde holds numerous patents having to do
with cold spraying and is the absolute market leader in the field.
“Originally,” says Heinrich, “we estimated world market volume
to be about 40 units.” Today, a bare three years after the first
prototype was built, the consortium has already sold 35 systems.
Heinrich reports a reassessment of the market potential for the
cold spray method: “We now think total demand is around 200.”
Peter Richter, Managing Director of CGT, recently acquired all the
basic patents from inventor Papyrin.
The latest segment to express interest in cold spraying is
the auto industry. At Unterschleissheim, Linde is now conducting
experiments on cast engine blocks with the aim of using the
technique to “heal” the fine cracks that arise in metal casting.
“Such tiny defects used to mean scrapping these expensive
castings,” says Krömmer. The loss was a big one, for automotive
engines are made of special alloys that are difficult and expensive
to produce. The cold spray method now makes it economical to
remedy these hairline cracks so that they do not impair engine life.
Recovering more gold with cold spraying
CGT recently received a most unusual inquiry from a gold mine
in Australia’s Queensland state. The mine uses cyanide salts –
derived from hydrogen cyanide – to extract the precious metal
by leaching from a very low-grade ore. In the piping that conveys the aggressive chemical, a damaged ball valve needed
a repair. The surface of the ball must be extremely resistant to
attack by the medium. The cold spray method was the only
technique by which the shutoff valve could be repaired; otherwise, the mine operator would have had to renovate the entire
piping system, at a cost of some 1.4 million euro. “The cold
spraying technology offers a tremendous potential for savings
on the refurbishment and protection of expensive components,”
says Heinrich, “and this is true for all industries.”
H.C. Starck, a maker of metal powders, has also recognized
this opportunity. The company joined the Cold Spray Competence
Group some time ago as a supplier of materials including titanium
and tantalum powders. “We certainly plan to work closely
together and hold frequent discussions with health-care professionals and engineers,” Heinrich states, “and our topics will
definitely not be limited to just these two metals.” It is quite
possible that other industries will take part in future discussions
of the cold spray method as well.
Electrical conductivity: The cold spray method is particularly
interesting for coating semiconductor components.
Michael Kömpf, based in Munich, is a freelance journalist
focusing on research and technology. He writes for (among
others) the customer publications of major industrial firms
and edits magazines in the corporate publishing field.
Links for further reading:
www.kaltgasspritzen.de
www.gts-ev.com
www.linde-gas.com
www.crp-ag.com
www.unibw-hamburg.de
Carrying current: The contacts of underground power lines are coated with
copper. This may be a future application for the cold spray method.
27
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Hydraulics
Linde hydraulic systems in the lumber industry
A powerful drive in the sawmill
The German lumber industry is booming, even overseas exports are now a big part of the
picture. To succeed in a competitive market, wood processing companies need machinery
that is above all efficient and reliable. Linde Hydraulics provides the entire power train for
“Made in Germany” handling machines. By Frank Grünberg
Johann Weinzierl’s business is buzzing in the truest sense of the
word. Every day the company he heads, Holzwerke Weinzierl
GmbH, located in the Bavarian town of Vilshofen, sells 2000 cubic
meters of softwood lumber. It takes 70 “road trains” a day to haul
the product. German sawmills regularly ship by sea, too. Most of
this lumber goes to the U.S., a country where frame houses are
typical and builders increasingly choose lumber imported from
Europe. It’s true that Canada’s huge forests lie just around the
corner, but in the end it is not distance but quality that tells. “Our
lumber,” says Weinzierl, “is more dimensionally true than what
you get from Canada.”
With some 55 employees and annual sales of 40 million euro,
Holzwerke Weinzierl ranks in the top third of German lumber
Softwood Lumber Statistics
–––– Domestic consumption –––– Domestic production
–––– Imports –––– Exports
cbm
18.000.000
14.000.000
10.000.000
6.000.000
2.000.000
0
1986
1990
1994
1998
2002
2006
estimated
The lumber industry is booming: Softwood lumber
output has grown by some 30 percent in the past
five years.
mills. Horse-drawn wagons were still the mode of transport
when Hans Weinzierl founded the company in 1934. Today his
son Johann and his nephew, Johann II, rely on state-of-the-art
technology to run the firm. Delivery times of just 48 hours
do not allow any idling or production halts, let alone equipment
failures, at Weinzierl. This rule applies equally to handling
machinery, the heavy vehicles – specialized for sawmill service –
that transport logs around the extensive yard. The loaders feature
all-wheel steering and so are highly maneuverable. The load
such a machine can handle is measured in square meters. The
Terex-Fuchs model MHL 464, for example, has a grab capacity of
3.2 square meters, about the same area as a lacrosse goal. The
MHL 464 is the biggest loader used at Weinzierl. The higher such
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Linde Technology June 2006
Industrial wood processing: Efficient and
economical procedures are essential in
the wood products business. Loaders must
therefore work extra-hard.
a machine can lift, the more it can carry and the better it can
maneuver through the narrow aisles between log piles, the more efficiently the sawmill can operate. Johann Weinzierl prizes
qualities like these: “No manufacturer has a better grasp of what
the lumber industry needs than Terex-Fuchs.”
Maneuvering rapidly through the millyard
The timber-handling machines owe both their precise control
and their strength to hydraulic components made by Linde
Hydraulics. Engineers at Linde’s Aschaffenburg plant work closely
with manufacturer Terex-Fuchs, from the concept right through
to the production of new equipment. “We credit part of our
customer’s success to our technology,” says Georg Klein, Sales
Department Manager for Linde Hydraulics. Like Weinzierl, TerexFuchs – located in Bad Schönborn near Karlsruhe – looks back
on a long tradition. Forgemaster Johannes Fuchs began making
agricultural implements in 1888. His successors brought out their
first hydraulic excavator in 1964 and their first loader in 1991.
Fuchs was acquired by the U.S. company Terex in 2002 and began
specializing in material-handling machinery. Today Terex-Fuchs
markets a total of 15 models; equipment specially built for log
handling includes the MHL 434, weighing 24 tonnes, and the
flagship MHL 464, at 38 tonnes. “The number 4 at the end stands
for all-wheel steering,” says Marketing Manager Carsten Bengs.
“Both these machines offer maneuverability that makes them
optimally suited to work in very narrow spaces. The boom hitched
on at the rear also makes for an excellent view of the entire
working area.”
Tonnes of softwood per day
Weinzierl uses two MHL 464 loaders to shift logs as fast as
possible from the log deck, called a Polter in the trade, to the
saw. Forklifts transport sawn wood from the stock boxes to
the drying kiln. In this way the handling machines carry some
1500 tonnes of softwood around the millyard – an area of 14
hectares, the size of 20 soccer fields – every day.
And these figures seem sure to increase, for German mill
exports are booming. Of the lumber produced in Germany today,
28 percent will be shipped to other countries. So, even though
the domestic construction industry continues to suffer, production
of softwood lumber in 2005 rose to 19.5 million cubic meters
(8.2 billion board feet), up 30 percent from just five years earlier.
The industry serves as an important link between forestry on the
one hand and the lumber business on the other. Logs are processed with almost no waste, either into finished products such
29
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Hydraulics
as squared timbers, framing, dimension lumber and paneling, or
into secondary products such as sawdust and chips for eager
customers in the pulp and paper industry. Even the bark is
claimed for use. The German wood products industry, with 2300
mills employing 26,000 people, racks up annual sales of around
four billion euro.
As in other industries, demand for standardized products is
on the upswing. Prices as late as the 1990s justified specialorder, short-run milling of posts, boards and rafters in customized
dimensions. The wood, however, often checked or warped
after construction and so did not meet the needs of modern
wood architecture. More and more customers began calling for
predried solid structural lumber in standard lengths. Large saws
with high feeds and high throughput capacities thus came to
dominate the industry. Holzwerke Weinzierl has now focused on
standard structural lumber as well. Johann Weinzierl describes
the business consequences this way: “Small mills today are trying
to establish themselves in niche markets while the bigger ones
push forward with standardization. The medium-sized operations
are fighting to survive.” This situation accounts for the trend
toward efficient, economical procedures, “which,” says Weinzierl,
“would not be possible without the right high-performance
machinery.”
Open hydraulic-loop system improves economy
All Terex-Fuchs machines employ an open-loop mobile hydraulic
system. A diesel engine drives a central double pump, which
supplies hydraulic energy to all consumers – such as the boom,
the stick, the grab, the drive motor and the slewing motor for
the upper carriage. This concept has the advantage of being
more economical than separate hydraulic loops with multiple
pumps for the consumers. But it is also more demanding in terms
In the sawmill: The loaders have to be
maneuvrable and powerful to be able
to transport the long timbers over the
extensive area of a sawmill.
Hydraulics underground
Linde Hydraulics also develops components for mining industry. No other
environment imposes such drastic
requirements on hydraulic systems as
underground work does. Machines
using Linde hydraulics include feeder
breakers, which break large chunks of
coal; roof bolters, which drive bolts
more than two meters long into the
mine roof; and roof scalers, which
prevent the uncontrolled fall of loose
portions of the roof.
The average life expectancy of
hydraulic components underground is
just a year, and components are replaced
after this time. Until then, however, all
components must function trouble-free,
because downtime would be extremely
expensive, costing the mine operator up
to US$100,000 per day. Linde Hydraulics
Hard labor in the seam: Linde hydraulics are a proven technology in coal mining as well.
therefore offers scheduled maintenance
and prompt on-site service in mines,
as well as quick delivery of spare parts
through an extensive dealer network.
In coal and salt mining, sensitivity
of control is more important than one
would suppose. Blast holes, for example,
must be drilled and sealed to centimeter
accuracy in order to prevent the ejection
of excessive amounts of rock.
In an environment where water,
dust and heat are prevalent, this accuracy requirement is an especially great
challenge.
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Linde Technology June 2006
of performance, because the central pump must immediately
respond to spontaneous load changes; for example, the grab
must not lose its strength even at the moment when the drive
motor is accelerating. To handle requirements like this, Linde
introduced load-sensing technology with Linde Synchronous
Control (LSC) in the 1980s and has continued to refine the system
since then. Load-sensing technology instantly changes the
flow and pressure of the central pump to suit varying needs,
while the LSC valves synchronize the motions of all consumers.
In this way the technology takes over part of the control task,
making it easy for the operator to exert precise control over
individual consumers at all speeds and loads – and concentrate
on the essentials without having to make corrections.
The results are reduced job stress and a boost in output.
High torque at low speed
The drive motor plays a key role in Terex-Fuchs machines. Linde
Hydraulics provides a large-displacement swash-plate hydraulic
motor for the purpose. Conventional hydraulic motors cannot
display the stiffness and freedom from pulsation delivered by
Linde Hydraulics motors at low speed, for example when starting
or at creep speed. Many other motors require multiple gears to
reduce the high torque of the fast-running motor to the low
speed of the wheels, and these systems suffer a loss of efficiency
as a result. Linde’s large-displacement motors, working on the
swash-plate principle, offer a different level of performance.
Special design features enable them to transmit large torques at
low speeds virtually without pulsations. Along with the hydraulic
and mechanical components, Linde also supplies the CEB 16
control system, from its Lintronic line, to limit the load on the
diesel engine. “The Linde electronics use state-of-the-art CAN
bus technology to communicate with the COM3 diesel engine,
which meets the latest emissions standards,” says Georg Klein.
Because sawmills are often located near residential areas,
Linde has also upgraded the acoustic characteristics of its hydraulic
pumps. A self-compensating silencer reduces pressure pulsations
generated in the regulating pump by as much as 70 percent and
thus also cuts down fluid noise, which can cause components
and bodywork to vibrate. As a result, the system runs much more
quietly. These qualities are important to Weinzierl as well, because
the managing director plans to go over from one- to two-shift
operation and open a new mill by the end of 2006. He still has
some important points to settle in terms of purchasing and sales,
but with regard to technology he means to stay true to his old
maxim: “We buy the best that is on the market.”
31
Main pump
Control-valve assembly
Boom, stick, grab
Slew drive
Drive motor
Frank Grünberg specializes in technology stories arising from
the contact of business and science. He lives in Wuppertal and
writes for technical publications and customer magazines.
Links for further reading:
www.linde-hydraulics.com
www.holzwerk-weinzierl.de
www.terex-fuchs.com
www.saegeindustrie.de
www.dhwr.de
Open hydraulic-loop system: A diesel engine drives the central
main pump, which supplies hydraulic energy to all consumers – grab,
boom, slewing mechanism and running gear – through a controlvalve assembly. Major advantage of the system: It is more economical
than separate hydraulic loops, needing only one central pump.
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CO2 recycling
CO2 conditioning at Marl Chemical Park
Too valuable for the stack
Carbon dioxide is one of the greenhouse gases, but many chemical and industrial processes
cannot get along without it. Demand is actually rising for carbon dioxide that can be put
to use in industry. On the northern boundary of the Ruhr district, Linde has invested ten
million euro to build a plant that will take in gas occurring as a byproduct and condition
it for further use. By Frank Grünberg
Question: What is as clear as water, boils at eleven degrees
Celsius, ignites readily and arises as a common intermediate
product in the chemical industry? Answer: ethylene oxide
(C2H4O). The main use of this substance is in the production of
ethylene glycol, a familiar coolant and antifreeze ingredient
that is also heavily employed in the making of cosmetics and
cleansers as well as plastics. Ethylene oxide is generated in a
simple chemical reaction when ethylene (C2H4) and oxygen (O2)
come together at 200 to 300 degrees Celsius in the presence of
a silver catalyst. But the reaction also gives rise to an unwanted
byproduct, because up to a fifth of the starting products react to
form carbon dioxide (CO2). This odorless compound is well known
as a greenhouse gas; its chief source is the burning of fossil fuels.
Experts have reached a consensus that the massive release of
carbon dioxide through human activity since the onset of industrialization is responsible for the observed climatic change. But
the unlovable gas also comes from chemical processes – at the
Sasol Germany plant, for example. In the Marl Chemical Park on
the northern edge of the Ruhr district, this South African concern
makes ingredients for shampoos, hair care products and detergents. Ethylene glycol is one, and it is in synthesizing ethylene
glycol that the facility generates carbon dioxide as well.
CO2 as a valuable raw material
Instead of being discharged, unused, into the atmosphere,
since mid-2004 this carbon dioxide has been put to good use. A
pipeline now conveys the gas to a nearby site where Linde Gas
operates a plant that conditions and liquefies it for industrial
use. It turns out that carbon dioxide is not just a greenhouse gas
but also a valuable raw material. Its properties have made it an
indispensable helper in modern industry: Under normal circumstances it is almost nonreactive, it dissolves easily in water and
when it sublimates directly from solid (“dry ice”) to gas, it makes
an impressive temperature change of 79 degrees Celsius. Carbon
dioxide is indispensable to purification and cleaning processes
in water-resource management, medical technology and
engineering. An effective way to clean steel parts, for example,
is to blast them with dry ice pellets as big as a grain of rice.
An important raw material: CO2 is a waste product of the
chemical industry. Conditioned in the new Linde plant, it can
be used in the food industry.
e32_Marl
11.07.2006
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Linde Technology June 2006
CO2 recycling: The Linde plant delivers some 60,000 tonnes of liquid carbon dioxide per year.
Carbon dioxide also plays a vital role in the food industry
whenever a product must be kept cold in the absence of electric
power. Catering at sports events and during airline flights would
not be possible without dry ice. Beverage manufacturers also use
gas from Linde’s Marl plant to carbonate mineral water. Carbonic
acid, the dissolved form of the gas, not only has a refreshing
action but also inhibits the growth of harmful microorganisms.
The greater the content of dissolved carbon dioxide, the longer
the product will remain good. Sparkling water generally contains
from four to eight grams of carbon dioxide per liter; the level
can be up to twelve grams per liter in sweetened soft drinks and
mixers. The demand is large, but there is a surplus of the gas, so
there is no need to make more of it. In Germany alone, industry
puts out some 500 million tonnes of climate-damaging carbon
dioxide per year in generating electricity and heat; by way of
comparison, only about 750,000 tonnes of CO2 is sold domestically
for industrial use. But the carbon dioxide discharged through
smokestacks and chimneys is not really suitable for critical applications in the food industry, because filtering out the pollutants
that always arise when coal, oil or gas is burned requires a great
deal of effort. The situation is different with byproduct gas from
chemical processes, which is very much better-defined and
highly concentrated and far easier to purify. It would therefore
be wasteful, on the one hand, to release carbon dioxide from
ethylene oxide production into the atmosphere without making
use of it; on the other hand, the producer of carbon dioxide has
an obligation to comply with national and European air pollution
standards.
Environmental protection and economics
The Linde plant at the Marl Chemical Park thus combines environmentalism and economics in an exemplary way. The facility
produces some 60,000 tonnes of liquid carbon dioxide per year,
receiving the gas from Sasol’s ethylene oxide plant. The purification
process is fairly simple: Trace organic compounds are removed by
catalytic combustion, while drying gets rid of residual moisture.
The last remaining contents of gas such as oxygen and nitrogen
are driven out by cryogenic liquefaction under pressure with
simultaneous boiling of the liquid carbon dioxide. The resulting
product is 99.95 percent pure. “This is in line with the most
stringent consumer legislation,” states Peter Wilhelm Koziel,
worldwide head of Carbon Dioxide Product Management for
Linde Gas.
Marl is the third German site where Linde is producing
carbon dioxide suitable for industrial use. At Leuna, in the state
of Saxony-Anhalt, the feedstock is a byproduct from a hydrogen
plant; at Bad Driburg, in the eastern part of North Rhine-Westphalia, the gas comes from a natural source where carbon dioxide
issues directly from the ground. Linde has invested ten million
euro in the new facility. “In this way,” says Koziel, “we are both
increasing our share of carbon dioxide production and enhancing
the reliability of supply for our customers.”
Until the mid-1950s, commercial use of carbon dioxide was
blocked largely by a lack of transportation capacity. Strong
market development did not begin until it became feasible to
ship the gas in liquefied form, at a gage pressure of 13 to 17 bar
and a temperature of minus 35 to minus 25 degrees Celsius.
Special containers of liquefied CO2 have been rolling along
international roads and rails ever since. The Linde plant at Marl
will help make certain that the flow does not cease.
Frank Grünberg specializes in technology stories arising from
the contact of business and science. He lives in Wuppertal and
writes for technical publications and customer magazines.
Links for further reading:
www.linde-process-engineering.com
www.chemsite.de
The Marl CO2 plant in figures
Capacity
Temperature
Pressure
Tank storage capacity
Power consumption
Wastewater
Construction time
Total investment
60,000 tonnes per year of liquid CO2
–32 degrees Celsius
14 bar
1200 tonnes
1.96 megawatt
1.9 m3/h
10 months
€10,000,000
33
e34_Oxygen
34
11.07.2006
12:18 Uhr
Seite 34
Oxygen generator
Mobile oxygen supply: The
portable O2 generator gives
lung patients much greater
mobility and comfort in their
everyday lives.
Fuel-cell technology aids lung patients
Deep breathing with pure oxygen
Combining fuel-cells and electrolysis in a unique way, Linde Medical Devices engineers
have designed a portable oxygen generator, wich serves patients suffering from chronic
respiratory disorders. The device will help patients improve their quality of life, gain
more mobility and enjoy sound, enjoy quietness. By Michael Kömpf
Some people can only rarely leave their homes or apartments
because even mild exertion is enough to leave them short of
breath. It would be better to say that their respiratory systems
are incapable of absorbing enough oxygen from the ambient air
during activity. These people suffer from a lung condition called
COPD, chronic obstructive pulmonary disease. An overexpansion
of the lungs, called emphysema, often results. The consequences
for those affected are dramatic: The respiratory passages produce
excess mucus, which is hard to eliminate by coughing. Patients
get out of breath after the mildest exertion because their blood
is not adequately enriched with oxygen. In severe cases, damage
to the heart can result. Unlike acute bronchitis, COPD cannot be
cured. The World Health Organization (WHO) estimates that 600
million people worldwide are afflicted with chronic obstructive
diseases of the respiratory tract, that is, COPD and emphysema.
In Germany these conditions are the leading cause of disability
and early retirement. They rank fourth in the U.S.A. and third in
Europe as causes of death. By the year 2020, COPD will advance
to third place among the leading causes of death worldwide.
“We think that about five to ten percent of the population
suffer from chronic respiratory diseases, including not only COPD
and emphysema but also asthma,” says Professor Thomas O. F.
Wagner, head of the Department of Pneumology and Allergology
at the Johann Wolfgang Goethe University, Frankfurt am Main.
“And the U.S. has around a million oxygen patients. This is just
the tip of the iceberg, the most severely ill.” Besides medication,
these people get the best respiratory relief from the direct administration of oxygen. Possible signs of COPD include wheezing
e34_Oxygen
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Linde Technology June 2006
and a feeling of constriction in the chest during exertion such as
climbing stairs. “Most cases are directly associated with inhalative
cigarette smoking,” says Wagner. Ninety percent of all COPD and
emphysema patients are present or former smokers. In population
centers, however, workplace stress due to pollutants or smog
also irritates the breathing passages and leads to shortness of
breath.
Patients get 99.78 ppercent pure oxygen
Karl-Heinz Hecker is out to help these people, for shortness of
breath and a sense of suffocation are among the worst things a
person can suffer. In the clear air of the Bavarian foothills of the
Alps, in the town of Aschau im Chiemgau, Hecker – together
with Professor Hans Kistenmacher of Linde Gas and Engineering
Innovation Management – runs Linde Medical Devices GmbH.
The company, founded only in autumn 2005, is specialized in
medical technology. “I’ve seen many hospitals from the inside,
and I’ve spoken with doctors and scientists, and with patients –
including children – who were coughing out their souls,” says
Hecker, himself a father of three. The patient’s needs are his
top priority: “We ask ourselves what the disease sufferer really
needs.” Hecker has always wanted to “make devices for patients.”
His team’s latest development is the Oxy-Gen lite® oxygen
35
generator, which uses electrolysis and fuel-cell technology to
produce high-purity oxygen for medicinal use. “It’s 99.78 pure
O2,” says Hecker, not without pride. This is what sets the new
generator, which is about the size of a boombox, clearly apart
from conventional oxygen supply devices. “In contrast to oxygen
concentrators, which merely compress the vital gas from the air
and concentrate it to 92 to 93 percent, we are generating it.
We break down water, which of course is made up of an oxygen
atom and two hydrogens, and use the resulting pure oxygen,”
Hecker explains. And the COPD patient needs the oxygen. To
build the device, Linde engineers combined electrolysis,
the splitting of water into its atomic constituents by the use of
electricity, with a proton-exchange-membrane (PEM) fuel-cell.
But the Oxy-Gen lite® does not just use electric current to break
water down into oxygen and hydrogen; the fuel-cell puts the
hydrogen atoms to work in their turn, making current. It furnishes
roughly one-third of the power needed for the electrolysis
process. The remainder comes through the power cable. “We
naturally have losses in the process. Otherwise, we’d have created
a perpetual-motion machine,” Hecker points out with a laugh.
Part of the water humidifies the oxygen, which is delivered to
the patient through a narrow tube and nasal prongs. Apart from
electricity, all the device consumes is distilled water, about two
COPD on the advance worldwide
Mortality projections
Leading causes of death (1990)
1. Coronary heart disease
2. Strokes
3. Lower respiratory diseases
4. Accidents
5. Infant mortality
6. COPD
7. Tuberculosis
8. Measles
9. Traffic accidents
Leading causes of death (2020)
1. Coronary heart disease
2. Strokes
3. COPD
4. Lower respiratory diseases
5. Lung cancer
6. Traffic accidents
7. Tuberculosis
8. Stomach cancer
9. HIV/AIDS
Rising danger: The chronic lung disease COPD will be the third most
common cause of death by 2020.
The abbreviation COPD stands for chronic obstructive pulmonary disease, a
condition in which the walls of the alveoli (the terminal cavities in the lungs)
become damaged. Instead of many small sacs with a large surface area,
individual large, flaccid cavities develop. These also squeeze the healthy alveoli.
The lung area that can take up oxygen becomes smaller and smaller as a result.
Once the alveoli have been damaged, they cannot be regenerated. The injured
alveoli do not take part in respiration. As the lungs continue to overexpand,
they become less effective in respiration.
e34_Oxygen
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Oxygen generator
to three liters a week. “And you can get that in any supermarket,”
adds Hecker. An extra advantage of the Linde technology for the
patient is natural humidification. One big problem in long-term
oxygen therapy is that oxygen, containing no humidity as it comes
from the appliance, dries out the mucous membranes and the
eyes. For this reason, all conventional devices up to now have
over-humidified the oxygen, consuming a relatively large
amount of water. Christian Gunkel, a research and development
engineer of Linde Medical Devices, explains: “By virtue of
our special generating process, the gas already has a relative
humidity of 80 percent, so the patient is protected against
drying in the nose and throat.”
The patient controls the machine
The high-tech device offers another advantage to the patient,
though: Oxy-Gen lite® provides the patient with oxygen on demand only, using a special microchip controller and precision
sensors. “The patient controls the machine, not the other way
around,” says Gunkel. “Our generator delivers oxygen at just the
right moment, taking its cue from the patient’s own breathing
and requiring no conscious action.” In human respiration, the air
taken in during the first fractions of a second is what actually
reaches the lungs. The rest of what is breathed in serves as a sort
of packing, not getting into the lungs but being breathed right
back out again. “So it is important to meter the oxygen in through
the nasal prongs at the optimal time so that it joins the inhaled
stream, passes into the lungs and gets transferred to the blood,”
Hecker explains. Special sensors monitor the patient’s requirement, involuntarily signaled through the breathing pulse,
and issue a command to supply oxygen. The process is controlled
by software also developed by Hecker and his team. Gunkel
describes the advantages of the “smooth ramp” function: “This
way, we get a smooth rise in pressure without extra irritation
to the mucous membranes.” About 80 percent of people for
whom long-term oxygen therapy is prescribed need at most two
liters of oxygen per minute. “A patient requires up to 16 hours of
oxygen in the day, depending on the severity of illness,” Wagner
says, “but some need it around the clock.” Linde’s medical
technology experts accordingly laid special stress on the product’s
noise output. “Patients have again and again complained that
the sound of conventional concentrators keeps them from
sleeping,” says Hecker, who has worked in medical technology
for some 30 years. He and his 17-member manufacturing and
development team therefore worked to reduce the noise
level. When the Oxy-Gen lite® is “making oxygen” it emits about
35 dB(A), the same as a very quiet room fan at a low setting.
Oxygen concentrators typically generate 40 to 50 dB(A) and are
thus more than twice as loud – about on a par with a refrigerator.
The extra noise, according to experts, can lead to attention
disorders.
Quality workmanship: Many parts, like the hose of the O2 generator shown here,
are assembled by hand, but a capacity expansion is planned as early as 2007.
e34_Oxygen
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Linde Technology June 2006
Unobtrusive: The patient gets oxygen from the generator
through a tube and small nasal prongs.
37
But Hecker did not simply want to build a quiet machine.
Mobility is also important to him: “Most lung patients have very
restricted mobility. Conventional concentrators are bulky and
heavy, weighing up to 30 kilograms,” he says. “A patient who
lives in a large apartment or house must either lay long hoses or
install connectors everywhere.” The new Linde product is helpful
in this area too. The device weighs just ten kilograms or so and
is easy to transport. “We have already installed a unit in the car
of a commercial representative who is in the field some twelve
hours a day and can’t do without his oxygen,” says Hecker, who
is now working to miniaturize the device further.
Boom in the oxygen business
The top priority for now is to increase production and further
optimize costs. An application was filed in April to have Oxy-Gen
lite® listed in the catalog of medications and appliances issued
by the German association of health-care insurers. As of about
May 2006, physicians will be able to prescribe the device, “but
patients can also buy the Oxy-Gen lite® themselves,” Hecker adds.
At present the Linde plant at Aschau can produce about
2000 units per year and is seeking to boost its annual capacity
to 3000 by early 2007. “At that point, though, we will have to
outsource manufacturing,” says Hecker. Worldwide sales of oxygen delivery devices now stand at around 400,000, and the
trend is upward because other fields have also been discovering
uses for pure oxygen.
Hecker knows that oxygen can have an invigorating effect
in cases of stress or exhaustion due to routine daily activity. He
takes a regular daily dose of oxygen and has his own Oxy-Gen
lite® humming away just behind his desk. He says a daily stroll in
the clear mountain air is “the best thing I can do for my health,”
but when he can’t take a walk, “the Oxy-Gen lite® helps me feel
a lot better.”
Michael Kömpf, based in Munich, is a freelance journalist
focusing on research and technology. He writes for (among
others) the customer publications of major industrial firms
and edits magazines in the corporate publishing field.
Increasing production: By early 2007, production capacity
is to reach 3000 units per year.
Online Screening for COPD:
In cooperation with the German Society of Pneumologists,
the Siemens health-care system has devised an online
test for COPD. Anyone who wishes to learn how likely it is
that he or she will suffer from COPD answers a series of
questions. If the result shows a high probability, the healthcare provider refers the patient to the in-house physician
or a lung specialist. www.sbk.org/gesundheitstests
(service available in German only)
Links for further reading:
www.linde-md.de
www.copd-aktuell.de
www.selbsthilfe-lot.de
www.patientenliga-atemwegserkrankungen.de
e38_Cryo
11.07.2006
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12:21 Uhr
Seite 38
LNG ferries
Norway converts ferries to LNG
Clean sailing
Thousands of ferries ply Norway’s innumerable fjords every day. Exhausts from these
mostly diesel-powered vessels mean trouble for the environment, so the Scandinavians
are now converting the fleet to less-polluting natural gas. Both nature and the ferry
operators are profiting from the move. By Katharina Becker
Norway is a land of reindeer, deep-blue fjords and ferries. It
probably has more ferries per capita than any other country on
Earth. And no wonder, for cities along the thousands of kilometers
of rugged coast are hard to get to by land. But the diesel-powered
vessels have also given Norway the highest per capita nitrogen
oxide emissions in Europe. In October 2004, the Scandinavians
ordered five novel ferries from a consortium including Cryo AB,
Linde’s Swedish subsidiary. Instead of conventional diesel, these
ships will run on liquefied natural gas (LNG).
An independent Norwegian study has shown that natural-gas
propulsion cuts nitrogen oxide emissions by nearly 90 percent
in comparison with diesel. Output of carbon dioxide, the most
notorious greenhouse gas, is also reduced by some 21 percent,
and the burning of LNG produces virtually no sulfur oxides at all.
“Among fossil fuels, natural gas is the cleanest energy that can
be imagined,” says Heinz Bauer, responsible for the technology
of natural gas plants at Linde Engineering. He maintains that the
benefits accrue not just to the environment but to human beings
too, “because all other fuels contain significantly higher levels
of carcinogens.”
Cryo AB, headquartered in Gothenburg, Sweden, designs and
builds the tanks for the eco-friendly ferries. “This 9-million-dollar
project is the largest in our company’s almost hundred-year
history,” says Lars-Erik Peterson. He is the Project Coordinator for
the ambitious undertaking, and he seems to be experiencing
some stress. The first ferries are due to enter service early in 2007
on the Halhjem-Skandvikvåg and Arsvågen-Mortavika routes.
While Cryo AB does have a lot of experience in building LNG
tanks for both transport and storage, the ferries of the future
called for a new design. The model was Norway’s MS Glutra, the
world’s first LNG-powered passenger ferry. “For this prototype
we built a propulsion system with tank and vaporizer,” Peterson
recalls. The firm has built similar systems for two supply vessels
belonging to the Norwegian Eidesvik line.
The five car and passenger ferries, each capable of carrying
up to 300 passengers and 20 cars, will each have two doublewalled stainless steel tanks. “The material is especially suitable
for the extremely low temperature of minus 163 degrees Celsius
at which natural gas becomes a liquid,” explains Peterson.
Regulators have approved ordinary steel only for temperatures
down to minus 50 degrees Celsius. Nothing short of high-alloy
(and therefore stainless) steels can withstand the extra degrees
of cold. Each tank is four meters in diameter and 22.5 meters
Idyll: The first LNG-fueled ferries will
soon be sailing Norway’s fjords.
11.07.2006
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Linde Technology June 2006
Voss
long and holds 125,000 liters of LNG. Construction began in April
2005, and the last pair of tanks has now been delivered. The
fuel tanks are fitted in the ship’s hold on the port and starboard
sides in order to save space. And the first of the new vessels
already has a name: MS Bergensfjord. She will carry passengers
between the old Hanseatic city of Bergen and the oil metropolis
of Stavanger in Norway’s southwest.
1876
Bergen
Kinsarvik
Tysse
Telavåg
Osøyri
Odda
Husnes
Rubbestadneset
LNG means lower fuel costs
How does one fill a ship’s tanks with supercold liquefied gas –
which, like any fuel, can also form an explosive mixture with
air? “Of course, smoking and open flames are strictly forbidden
anywhere nearby,” Peterson says. Even the machinery used
must not heat up. The ferries will get their LNG from a tanker truck
or a pump. Bauer explains the principle: “The arrangement is
like a lock for ships. The liquefied gas passes through two valves
connected in series, which prevent it from flowing backward.”
Natural gas is lighter than air, so if a leak occurs in the system
the gas will escape upward rather than accumulating inside the
ship’s hull. The propulsion machinery is also designed so that
the supply of gas is immediately cut off in case of a leak.
Modern “Made by Linde” environmental technology is paying
off for the ferry lines, although it is not yet possible to put an
exact figure on how much the new ferries will save. But the
natural-gas-fueled supply vessels already in service provide a
good reference figure. For each ship, the owner is saving 45,000
euro through lower fuel costs and longer maintenance intervals
– 45,000 euro per month, that is! What is more, the operators
receive certificates that regulate the permissible emission of
pollutants. These ships will emit far less than their permitted
levels, so the owners can sell the remaining certificates. “That
will be a lucrative bonus for them,” says Peterson.
Ølen
Sauda
Haukeligrend
Sand
Haugesund
Kopervik
Skudeneshavn
n
rde
Boknafjo
Sola
Sandnees
Nedstrand
Hjelmeland
Stavanger
Tourist route: The first LNG-fueled ferry will carry passengers between
Bergen and Stavanger.
Eco-friendly vessel: A frame from a computer animation showing the
MS Bergensfjord, which will soon be carrying passengers and cars.
Katharina Becker is a freelance business journalist based in
Frankfurt am Main. She writes for, among other outlets, the
AFP wire service and a variety of newspapers and magazines.
Links for further reading:
www.cryo.se
www.aga.com/cryo
www.eidesvik.no
www.vik-sandvik.com
www.abb.com/marine
39
Linde on board: This natural-gas tank, specially developed for LNGpowered ferries, is being shipped for installation from Tuleca, Romania.
Otra
e38_Cryo
e40_GTL
11.07.2006
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Seite 40
Gas-to-liquid
Linde technology for clean fuel
Designer-diesel from natural gas
Gas-to-liquid (GTL) technology has lain slumbering for decades. Converting natural gas to
liquid fuel simply cost too much. As the price of crude oil rises, however, this technological
Sleeping Beauty is coming awake. Experts forecast a boom in the next few years, because
synthetic diesel is clean and virtually sulfur-free. After years of GTL involvement, Linde now
means to put its know-how to work on new projects. By Tim Schröder
In the morning, as technicians from Mossel Bay and the vicinity
drive to work in the industrial area, gazelles leap alongside their
cars and antelopes gaze at them over the tall grass. Mossel Bay
(also called Mosselbaai) is a little spot at the southern tip of
Africa. The N2 national highway to Capetown passes nearby; this
section, following the Indian Ocean shore, is called the “Garden
Route.” Every day tourists in rented cars stream along the winding
coast road, through a countryside of wildlife parks and verdant
gardens, always in hopes they may see a whale spouting. A
stone’s throw from the highway and a few kilometers from Mossel
Bay, slender white towers reach toward the sky. They belong to
an air separator plant at the world’s largest gas-to-liquid plant,
where natural gas is made into diesel fuel. The facility has been
humming along for 15 years, not greatly bothering the gazelles
in the wildlife preserve next door. In its reliable, unspectacular
way, the Mossel Bay GTL Plant produces 34,000 barrels a day of
diesel fuel (1 barrel = 159 liters) as well as other chemicals such
as kerosene, lubricating oil and naphtha (which also occurs as a
product in petroleum refining).
The impressive plant long remained an anomaly little known
to the world at large. GTL was viewed as the oil industry’s
stepchild, because making fuels from crude oil rather than from
gas is cheaper and therefore preferable. But the presence of
large natural gas deposits out in the Indian Ocean, 85 kilometers
from the coast, led the South African company Mossgas (now
PetroSA) to commission a feasibility study for a GTL refinery. That
was in 1985; two years later, the company decided to erect the
plant. Linde got an order for two air separation plants, which
would generate the oxygen needed for making diesel from natural
gas. “GTL refineries become highly profitable when the price
reaches 50 dollars a barrel,” says Dr. Gerhard Beysel, Linde’s
head of development and marketing for air separation plants.
The depletion of petroleum reserves has now made it
necessary to take the GTL alternative seriously, and so oil
companies are now pushing this technology hard. Besides
Mossel Bay, there is just one other GTL plant in the world, in the
Malaysian city of Bintulu. Operated by Shell since 1993, this
facility produces 14,000 barrels a day. In 2006, however, a new
Environmental protection: Synthetic diesel fuel contains
far lower levels of pollutants and is nearly sulfur-free.
These qualities benefit the environment.
e40_GTL
11.07.2006
12:23 Uhr
Seite 41
Linde Technology June 2006
41
Reliable, clean diesel: The Sasol Chervron
GTL Challenge team successfully tested the designer
fuel on their trip from South Africa to Qatar.
refinery will come on stream in Qatar: the South African company
Sasol’s Oryx plant. It will also have a capacity of 34,000 barrels
per day. Shell is planning to build a huge “Pearl” GTL refinery in
Qatar with a capacity of 140,000 barrels a day starting in 2009.
Qatar Petroleum, a partner in these ventures, has resolved to
make Qatar the GTL capital of the world. New facilities are also
planned for Australia and Nigeria, and most of the oil companies
have started their own GTL programs. No question about it,
GTL is more popular than ever before. Several factors have
contributed to this change. First, in view of dwindling crude oil
reserves, natural gas is gaining recognition as a dependable fuel
source – also via the GTL route – that will remain abundant for
decades to come. Because the transportation sector will continue
to rely chiefly on fossil fuels for some years, GTL diesel is a fuel
with a future. What is more, GTL conversion makes it possible to
exploit even remote gas fields, since refining natural gas to diesel
creates a much more valuable product that can be profitably
delivered by classical means of transportation.
Exhaust without nitrogen oxides
But it is another advantage of GTL diesel that is now commanding
attention. Unlike diesel fuel from crude oil, it contains almost no
sulfur and produces neither toxic aromatics (such as carcinogenic
benzene) nor nitrogen oxides. The low sulfur content means that
combustion in the engine generates much less soot. In other
words, GTL diesel may contribute significantly to improved air
quality in large cities and densely populated areas. And it doesn’t
stop there: GTL diesel more than complies with European exhaust
emissions limits and even those of California, strictest in the
world. EU regulations, for example, call for diesel to contain only
0.001 percent sulfur as of 2011; the current limit is 0.005 percent.
In contrast to GTL fuel, conventional diesel requires costly
desulfurization. Experts estimate that daily production of
conventional diesel now stands at 11 million barrels. The London
Centre for Global Energy Studies projects that GTL output will
rise to 1.5 million barrels per day by the year 2015. Then as now,
the cleaner alternative fuel will cover only a fraction of demand,
but it is highly suitable for blending. GTL diesel is a premium
Comparison of diesel fuels
*) Source: Sirman, “Emissions comparison of alternative fuels in an advanced automotive diesel engine,” SAE paper 2000-01-2048
Property
Cetane number
Sulfur content (ppm)
Reduction in soluble PAH
Reduction of gaseous PAH
Density, kg/L
Content of polyaromatics (vol. %)
Conventional diesel
40 to 50
350 (EU-Norm from 2008: 10)
The bright outlook for GTL diesel as a fuel is
due above all to its high cetane number. This
measure describes the content of certain
long-chain hydrocarbons (hexadecane). In
a diesel engine, a fuel with a high cetane
number ignites at the optimal time, so that
the pistons move easily and the engine runs
more quietly. GTL diesel is further marked
by an extremely low level of pollutants and
impurities such as sulfur, toxic aromatics and
metal compounds. The burning of GTL diesel
also produces much lower levels of polycyclic
aromatic hydrocarbons (PAH), which are a
health hazard. For these reasons, GTL diesel
is the fuel of choice for improving air quality
in densely populated areas and megacities.
Engines burning it give off less carbon
0.82 to 0.86
EU-diesel: 11
GTL diesel
> 70
<5
about a max of 61.1 % *)
about a max of 96.7 % *)
0.78
0
monoxide, soot and fine particulates. The
low sulfur content also means that GTL
diesel puts hardly any burden on exhaust
treatment systems such as particulate filters,
which are susceptible to contamination.
This fuel is so clean that all international
exhaust emissions standards can be met
through its use.
e40_GTL
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Gas-to-liquid
GTL refineries (over 5000 Barrels/Day)
Name
Mossel Bay
Bintulu
Oryx
Escravos
Pearl
Location
Mossel Bay, South Africa
Bintulu, Malaysia
Ras Laffan, Qatar
Nigeria
Ras Laffan, Qatar
Operational since
1991
1993
2006
2008
2009/2010
Capacity (Barrels/Day)
34,000
14,000
34,000
34,000
2 x 70,000
Operator/Producer
Petro SA
Shell
Sasol/QP
Sasol/Chevron
Shell/QP
GTL now lucrative: Sasol and Shell are pushing the development of synthetic diesel fuel.
product that can be used to upgrade conventional diesel – not
just because of its cleanness, but also because of its high cetane
number. (The higher the cetane number – a measure relating
to the content of this long-chain hydrocarbon – the more
uniformly the fuel burns and the more smoothly the engine
runs.) Conventional diesel often has to have its cetane number
boosted with chemical additives; the natural gas derivative, on
the other hand, has a superlatively high cetane number.
Before GTL diesel or naphtha can be charged into tank
trucks and ships for transport to destinations all over the world,
natural gas must go through a three-step process. Several processes now exist for converting the feedstock, which contains
90 percent methane, but the principle is the same in each case.
The first step is to react natural gas with atmospheric oxygen to
get a mixture of hydrogen (H2) and carbon monoxide (CO) called
synthesis gas or syngas. The proportions of the species can be
controlled by varying the reaction conditions; an H2/CO ratio of
2 to 1 is optimal for downstream refining to diesel fuel. In the
second step, the carbon monoxide/hydrogen mixture is admitted
to a Fischer-Tropsch reactor, the heart of the GTL refinery. The
reactor is named after the German chemists Franz Fischer and
Hans Tropsch, who in the 1920s devised a process for making
synthetic fuels from syngas (which was then obtained from coal).
The key to the success of the process was an alkali metalpromoted iron catalyst. This second step in the refining process
converts the syngas to waxlike paraffins and long-chain hydrocarbons, which can then be cleaved (cracked) into shorter
chains in the third step. The procedure is not so different from
what is done to crude oil.
GTL becomes competitive
Equipment for producing synthesis gas accounts for more than
half the cost of building a GTL refinery. This cost item was long a
drag on the establishment of gas-to-liquid technology. “But the
high price of crude oil is making this process more and more
profitable,” says Beysel’s colleague Thomas Haberle, manager
of GTL refinery engineering for the Linde hydrogen and syngas
plant product line. In the Munich suburb of Pullach, he is hard at
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Linde Technology June 2006
work to enhance the recognition of Linde technology in the GTL
sector. Linde currently has several hundred of these components
in operation worldwide and in this way has acquired profound
knowledge that will figure heavily in the construction of future
GTL refineries. “We can do far more than separate air,” Haberle
states. “With our know-how, we offer the right solution for every
step in the GTL process apart from the Fischer-Tropsch synthesis
itself.” Linde engineers have recently erected several large POX
(partial oxidation) units, the components where natural gas is
oxidized with atmospheric oxygen to form syngas. In most cases,
the subsequent use of the syngas is for other processes than
Fischer-Tropsch synthesis. At La Porte, Texas, Linde operates the
world’s biggest POX plant with natural gas as feedstock.
Mexican air separator the world’s largest
The team at Pullach also has an impressive record in terms of
air separators. In 2001, Linde built the world’s biggest plant of
this kind in Mexico’s Cantarell oilfield. It separates twelve million
cubic meters of air per day. The useful product here is not oxygen,
as in GTL refining, but nitrogen. Powerful compressors inject
nitrogen into the underground formation to boost the flow of oil
to the surface. Reference projects such as this put Linde in a good
starting position for the “Pearl” project in Qatar.
Most air separation plants have been used to produce a
single gas, either nitrogen or oxygen, with the other component
released back to the atmosphere. Beysel thinks this is wasteful.
The engineer sees the growing interest in GTL as an opportunity
to make more efficient use of distillation towers by combining
enhanced oil recovery with GTL refining. “Gas from oil formations
is still being flared off uselessly in many places,” explains Beysel.
“By coupling production wells with GTL plants, we could get value
from the gas while using both nitrogen and oxygen.” It’s true
that GTL refining will not pay off for every oilfield. Nigeria and
Record: In the Cantarell oilfield, Mexico, Linde built the world’s biggest
air separation plant in 2001.
the international oil companies that have production facilities
there are following a good example, though: Flaring will
be banned as of 2008. Instead of being discharged into the
atmosphere, the valuable product will be converted to GTL
diesel – an extra benefit that was inconceivable without Linde
technology.
Tim Schröder lives in Oldenburg and works there as a freelance
science journalist. He writes for publications including Neue
Zürcher Zeitung, Bild der Wissenschaft and Mare.
Links for further reading:
www.energy.ca.gov/afvs/vehicle_fact_sheets/gtl.html
www.chemlink.com.au/gtl.htm
www.greencarcongress.com/2006/04/sasol_chevron_s.html
www2.exxonmobil.com/corporate/Campaign/
Campaign_energydemand_GTL.asp
Converting natural gas to liquid fuel
Air
Natural gas
Separation
Gas processing
Oxygen O2
Liquefied petroleum gas (LPG)
Methane CH4
Diesel
Gas synthesis
CO
H2
Fischer-Tropschprocess
Long-chain
liquid hydrocarbons
Cracking
Naphta
Waxes
In the first step, oxygen [O2] separated from air is admitted to a reactor with methane [CH4]. The product is synthesis gas, a mixture of hydrogen [H2]
and carbon monoxide [CO]. The syngas passes into a Fischer-Tropsch reactor where catalysts help reform it into long-chain hydrocarbon molecules. The
long-chain hydrocarbons are fed into a cracking process and converted into diesel or other liquid fuels, naphtha and waxes. Cracking uses heat and
pressure to break down long-chain hydrocarbons and produce lighter hydrocarbons.
Mossel Bay: Sasol has been making liquid fuel from
natural gas in South Africa for 15 years.
43
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Innovative ideas and
technological competence
Catching up with Linde Technology:
Download these back issues from
www.linde.com
Linde Technology June 2006
Topics: Papermaking with oxygen | “Green”
hydrogen from algae | Fuel cells help lung patients |
Synthetic fuel
Linde Technology January 2006
Topics: Natural gas from the Barents Sea |
CO2-free coal power plant | Lift trucks in container
port | Ionic compressors
Linde Technology July 2005
Topics: Hydrogen as a driver of innovation |
Helium for research | Engineering in china
Linde Technology December 2004
Topics: Oxygen usage in steel production |
Forklift truck with fuel cell | Biotechnology for
innovative medications
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Reports on Science and Technology
June 2006
Linde Technology
LeadIng.
Featured topic
“Environmental protection and sustainability”:
Papermaking with oxygen
“Green” hydrogen from algae
Other topics:
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ISSN-1612-2232
Fuel cells help lung patients
Synthetic fuel