BMW and hydrogen: part one

BMW and hydrogen: part one

The roar of the impending storm still echoed in the sky as the huge plane approached the landing site near New Jersey. On May 6, 1937, the Hindenburg airship made its first flight of the season, taking 97 passengers on board.

In a few days, a huge balloon filled with hydrogen is due to fly back to Frankfurt am Main. All seats on the flight have long been reserved by American citizens eager to witness the coronation of British King George VI, but fate decreed that these passengers would never board the aircraft giant.

Shortly after the completion of preparations for landing the airship, its commander Rosendahl noticed a flame on its hull, and a few seconds later the huge ball turned into an ominous flying log, leaving only pitiful metal debris on the ground after another half a minute. One of the most surprising things about this story is the gratifying fact that many of the passengers aboard the lit airship eventually managed to survive.

Count Ferdinand von Zeppelin dreamed of flying in a lighter-than-air vehicle at the end of the XNUMXth century, sketching a rough diagram of a light gas-filled aircraft and launching projects for its practical implementation. Zeppelin lived long enough to see his creation gradually enter people's lives, and died in 1917, shortly before his country lost World War I, and the use of his ships was prohibited by the Treaty of Versailles. The Zeppelins were forgotten for many years, but everything changes again at a dizzying speed with the coming to power of Hitler. The new head of Zeppelin, Dr. Hugo Eckner, strongly believes that a number of significant technological changes are required in the design of airships, the main one of which is the replacement of flammable and dangerous hydrogen with helium. Unfortunately, however, the United States, which at the time was the only producer of this strategic raw material, could not sell helium to Germany under a special law passed by Congress in 1923. This is why the new ship, designated LZ 129, is eventually fueled with hydrogen.

The construction of a huge new balloon made of light aluminum alloys reaches a length of almost 300 meters and has a diameter of about 45 meters. The giant aircraft, equivalent to the Titanic, is powered by four 16-cylinder diesel engines, each with 1300 hp. Naturally, Hitler did not miss the opportunity to turn the "Hindenburg" into a vivid propaganda symbol of Nazi Germany and did everything possible to accelerate the start of its exploitation. As a result, already in 1936 the "spectacular" airship made regular transatlantic flights.

On its maiden flight in 1937, a crowd of excited spectators, enthusiastic welcomes, relatives and journalists gathered at the New Jersey landing site, many of whom waited for hours for the storm to subside. Even the radio covers an interesting event. At some point, anxious expectation is interrupted by the silence of the speaker, who, after a moment, hysterically shouts: “A huge fireball falls from the sky! There is no one alive ... The ship suddenly lights up and instantly looks like a giant burning torch. Some passengers in panic began to jump from the gondola to escape the horrific fire, but this proved fatal for them due to the height of one hundred meters. In the end, only a few of the passengers who are waiting for the airship to approach the ground survive, but many of them are badly burned. At some point, the ship could not withstand the damage of the raging fire, and thousands of liters of ballast water in the bow began to pour into the ground. The Hindenburg rolls rapidly, the burning rear crashes into the ground and ends in complete destruction in 34 seconds. The shock of the spectacle shakes the crowd gathered on the ground. At that time, the official cause of the crash was considered to be thunder, which caused the ignition of hydrogen, but in recent years, the German and American experts have categorically argued that the tragedy with the ship Hindenburg, which passed through many storms without problems, was the cause of the disaster. After numerous observations of the footage from the archive film, they came to the conclusion that the fire started because of the combustible paint covering the airship's skin. The fire of the German airship is one of the most ominous disasters in human history, and the memory of this terrible event is still very painful for many. Even today, mentions of the words "airship" and "hydrogen" evoke associations with a fiery hell in New Jersey, although if "domesticated" appropriately, the lightest and most abundant gas in nature could be extremely useful, despite its dangerous properties. According to a large number of modern scientists, the present era of hydrogen still continues, although at the same time, another large part of the scientific community is skeptical about such extreme manifestations of optimism. Among the optimists who support the first hypothesis, and the most convinced supporters of the hydrogen idea, there must undoubtedly be the Bavarians from BMW... The German car company is probably best aware of the inevitable challenges on the road to a hydrogen economy and, above all, overcoming the difficulties in the transition from hydrocarbon fuels to hydrogen.

Ambition

The very idea of ​​using fuels that are as environmentally friendly and inexhaustible as fuel supplies sounds like magic to humanity in an energy struggle. Today there are more than one or two "hydrogen societies" whose mission is to foster a positive attitude towards light gas and constantly organize meetings, symposia and exhibitions. The tire company Michelin, for example, is investing heavily in the increasingly popular Michelin Challenge Bibendum, a global forum for sustainable fuels and vehicles focused on hydrogen.

However, the optimism emanating from speeches at such forums is still not enough for the practical implementation of the beautiful hydrogen idyll, and entering the hydrogen economy is an infinitely difficult and unrealizable event at this technological stage of civilization development.

Recently, however, humanity has been striving to use more and more alternative energy sources, namely, hydrogen can become an important bridge for storing solar, wind, water and biomass energy, converting it into chemical energy. ... In simple terms, this means that the electricity produced by these natural sources cannot be stored in large volumes, but can be used to produce hydrogen by breaking down water into oxygen and hydrogen.

As strange as it sounds, some oil companies are among the main supporters of this scheme, among which the most consistent is the British oil giant BP, which has a specific investment strategy for significant investments in this area. Of course, hydrogen can also be extracted from non-renewable sources of hydrocarbons, but in this case, humanity must look for a solution to the problem of storing carbon dioxide obtained in this process. It is an indisputable fact that the technological problems of production, storage and transportation of hydrogen are solvable - in practice, this gas is already produced in huge quantities and is used as a feedstock in the chemical and petrochemical industries. In these cases, however, the high cost of hydrogen is not fatal, since it “melts” into the high cost of the products in the synthesis of which it participates.

However, the issue of using light gas as an energy source is somewhat more complicated. Scientists have been racking their brains for a long time in search of a possible strategic alternative to fuel oil, and so far they have come to the unanimous opinion that hydrogen is the most environmentally friendly and affordable in sufficient quantities of energy. Only he meets all the necessary requirements for a smooth transition to change the current status quo. At the heart of all these benefits is a simple but very important fact - the production and use of hydrogen revolves around the natural cycle of combining and decomposing water ... If humanity improves production methods using natural sources such as solar energy, wind and water, hydrogen can be produced and use in unlimited quantities without emitting any harmful emissions. As a renewable energy source, hydrogen has long been the result of significant research in various programs in North America, Europe and Japan. The latter, in turn, are part of a wide range of joint projects aimed at creating a complete hydrogen infrastructure, including production, storage, transportation and distribution. Often these developments are accompanied by significant government subsidies and are based on international agreements. In November 2003, for example, the International Partnership Agreement for the Hydrogen Economy was signed, which includes the world's largest industrialized countries such as Australia, Brazil, Canada, China, France, Germany, Iceland, India, Italy and Japan. , Norway, Korea, Russia, UK, USA and European Commission. The goal of this international collaboration is “to organize, stimulate and unite the efforts of various organizations on the way to the hydrogen era, as well as to support the creation of technologies for the production, storage and distribution of hydrogen”.

The possible route to using this clean fuel in the automotive sector can be twofold. One of them is devices known as "fuel cells", in which the chemical combination of hydrogen with oxygen from the air releases electricity, and the second is the development of technologies for using liquid hydrogen as fuel in the cylinders of a classic internal combustion engine. The second direction is psychologically closer to both consumers and car companies, and BMW is its most prominent supporter.

Production

Currently, more than 600 billion cubic meters of pure hydrogen are produced worldwide. The main raw material for its production is natural gas, which is processed in a process known as "reforming". Smaller amounts of hydrogen are recovered by other processes such as chlorine electrolysis, heavy oil partial oxidation, coal gasification, coal pyrolysis to produce coke, and gasoline reforming. About half of the world's hydrogen production is used for the synthesis of ammonia (which is used as a feedstock in the production of fertilizers), in oil refining and in the synthesis of methanol. These production schemes burden the environment to one degree or another, and, unfortunately, none of them offer a meaningful alternative to the current energy status quo - firstly, because they use non-renewable sources, and secondly, because, that the production gives off unwanted substances such as carbon dioxide, which is the main culprit. The greenhouse effect. An interesting proposal to tackle this problem has recently been made by researchers funded by the European Union and the German government who have created a so-called "sequestration" technology, in which carbon dioxide from the production of hydrogen from natural gas is pumped into old depleted fields. oil, natural gas or coal. However, this process is not easy to implement, since neither oil nor gas fields are real cavities in the earth's crust, but most often are porous sandy structures.

The most promising future method of producing hydrogen remains the electrical decomposition of water, known since elementary school. The principle is extremely simple - an electric voltage is applied to two electrodes immersed in a water bath, while positively charged hydrogen ions pass to the negative electrode, and negatively charged oxygen ions - to the positive one. In practice, several basic methods are used for this electrochemical decomposition of water - "alkaline electrolysis", "membrane electrolysis", "high pressure electrolysis" and "high temperature electrolysis".

Everything would be perfect if the simple arithmetic of division did not interfere with the extremely important problem of the origin of the electricity needed for this purpose. The fact is that at present, during its production, harmful by-products are inevitably released, the amount and type of which varies depending on how it is done, and, above all, the production of electricity is an ineffective and very expensive process.

Breaking the vicious and closing the cycle of clean energy is currently only possible when using natural and especially solar energy to generate electricity needed to decompose water. Solving this task will undoubtedly require a lot of time, money and effort, but in many parts of the world, generating electricity in this way has already become a fact.

BMW, for example, is playing an active role in the creation and development of solar power plants. The power plant, built in the small Bavarian town of Neuburg, uses photovoltaic cells to generate energy that produces hydrogen. The systems that use solar energy to heat water are particularly interesting, according to the company's engineers, and as a result, steam powers electric generators - such solar power plants are already operating in the Mojave Desert in California, which generates 354 MW of electricity. Wind power is also becoming more important, and wind farms on the coasts of countries such as the USA, Germany, the Netherlands, Belgium and Ireland are playing an increasingly important economic role. There are also companies producing hydrogen from biomass in different parts of the world.

Storage

Hydrogen can be stored in large quantities both in gas and liquid phases. The largest of these reservoirs, in which the hydrogen is at a relatively low pressure, are called "gas meters". Medium and smaller tanks are suitable for storing hydrogen at a pressure of 30 bar, while the smallest special tanks (expensive devices made of special steel or composite materials reinforced with carbon fiber) maintain a constant pressure of 400 bar.

Hydrogen can also be stored in the liquid phase at -253 ° C per unit volume, containing 0 times more energy than when stored at 1,78 bar - to achieve an equivalent amount of energy in liquefied hydrogen per unit volume, the gas must be compressed up to 700 bar. It is precisely because of the higher energy efficiency of cooled hydrogen that BMW is cooperating with the German refrigeration concern Linde, which has developed modern cryogenic devices for liquefying and storing hydrogen. Scientists also offer other, but less applicable alternatives to hydrogen storage - for example, storage under pressure in special metal flour in the form of metal hydrides, etc.

Transportation

In areas with a high concentration of chemical plants and oil refineries, a hydrogen transmission network has already been established. In general, the technology is similar to the transportation of natural gas, but the use of the latter for the needs of hydrogen is not always possible. However, even in the last century, many houses in European cities were lit by a light gas pipeline, which contained up to 50% hydrogen and was used as fuel for the first stationary internal combustion engines. Today's level of technology also allows the transcontinental transport of liquefied hydrogen via existing cryogenic tankers similar to those used for natural gas. At present, the greatest hopes and greatest efforts are being made by scientists and engineers in the field of creating adequate technologies for liquefying and transporting liquid hydrogen. In this sense, it is these ships, cryogenic railway tanks and trucks that can become the basis for the future transport of hydrogen. In April 2004, the first-of-its-kind liquefied hydrogen filling station, jointly developed by BMW and Steyr, was opened in the immediate vicinity of Munich Airport. With its help, filling the tanks with liquefied hydrogen is carried out fully automatically, without participation and without risk for the car driver.

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