Linde Technology
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Linde Technology
e00_Umschlag 13.07.2006 14:51 Uhr Seite U1 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 e00_Umschlag 11.07.2006 17:42 Uhr Seite U2 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 e02_Editorial_Inhalt 11.07.2006 12:52 Uhr Seite 1 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 1 e02_Editorial_Inhalt 12:52 Uhr Seite 2 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. e02_Editorial_Inhalt 11.07.2006 12:52 Uhr Seite 3 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 e04_News 11.07.2006 4 10:59 Uhr Seite 4 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. e04_News 11.07.2006 10:59 Uhr Seite 5 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. 5 e04_News 11.07.2006 6 10:59 Uhr Seite 6 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. e04_News 13.07.2006 14:55 Uhr Seite 7 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. 7 e08_Papier Featured topic: “Environmental protection and sustainability“ 8 11.07.2006 11:22 Uhr Seite 8 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 e08_Papier 11.07.2006 11:22 Uhr Seite 9 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 9 e08_Papier 11:22 Uhr Seite 10 Paper manufacturing Featured topic: “Environmental protection and sustainability“ 10 11.07.2006 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 e08_Papier 11.07.2006 11:22 Uhr Seite 11 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 11 Featured topic: “Environmental protection and sustainability“ e12_Biowasserstoff 12 11.07.2006 11:26 Uhr Seite 12 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. e12_Biowasserstoff 11.07.2006 11:26 Uhr Seite 13 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 13 e12_Biowasserstoff Featured topic: “Environmental protection and sustainability“ 14 11.07.2006 11:26 Uhr Seite 14 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 11.07.2006 11:29 Uhr Seite 15 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?” e15_Kistenmacher Featured topic: “Environmental protection and sustainability“ 16 11.07.2006 11:29 Uhr Seite 16 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 e15_Kistenmacher 11.07.2006 11:30 Uhr Seite 17 Linde Technology June 2006 “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. 17 e18_Abwasser 11:43 Uhr Seite 18 Wastewater treatment Featured topic: “Environmental protection and sustainability“ 18 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 e18_Abwasser 11.07.2006 11:43 Uhr Seite 19 Linde Technology June 2006 19 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. e18_Abwasser Featured topic: “Environmental protection and sustainability“ 20 11.07.2006 11:43 Uhr Seite 20 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 e18_Abwasser 11.07.2006 11:43 Uhr Seite 21 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 21 e22_Fred_Butler 22 11.07.2006 11:46 Uhr Seite 22 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. e22_Fred_Butler 13.07.2006 14:42 Uhr Seite 23 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 e24_Kaltgas 24 11.07.2006 11:51 Uhr Seite 24 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. e24_Kaltgas 11.07.2006 11:51 Uhr Seite 25 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 e24_Kaltgas 26 11.07.2006 11:51 Uhr Seite 26 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 e24_Kaltgas 11.07.2006 11:52 Uhr Seite 27 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 e28_Hydraulik 11.07.2006 28 11:56 Uhr Seite 28 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 e28_Hydraulik 13.07.2006 14:44 Uhr Seite 29 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 e28_Hydraulik 30 11.07.2006 11:56 Uhr Seite 30 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. e28_Hydraulik 11.07.2006 11:57 Uhr Seite 31 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. e32_Marl 11.07.2006 32 12:08 Uhr Seite 32 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 12:08 Uhr Seite 33 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 11.07.2006 12:18 Uhr Seite 35 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 36 11.07.2006 12:18 Uhr Seite 36 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 11.07.2006 12:18 Uhr Seite 37 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 38 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 12:21 Uhr Seite 39 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 40 12:23 Uhr 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 11.07.2006 42 12:23 Uhr Seite 42 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 e40_GTL 11.07.2006 12:23 Uhr Seite 43 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 e00_Umschlag 11.07.2006 17:42 Uhr Seite U2 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 e00_Umschlag 13.07.2006 14:51 Uhr Seite U1 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