Fuel cell do it yourself at home. Fuel cell technology and its use in automobiles

In light of recent events related to overheating, fires and even explosions of laptops due to the fault of lithium-ion batteries, one cannot help but recall new alternative technologies that, according to most experts, in the future will be able to supplement or replace traditional batteries today. We are talking about new power sources - fuel cells.

According to the rule of thumb, formulated 40 years ago by one of the founders of Intel, Gordon Moore, processor performance doubles every 18 months. Batteries can't keep up with the chips. Their capacity, according to experts, increases only by 10% per year.

The fuel cell operates on the basis of a cellular (porous) membrane that separates the anode and cathode space of the fuel cell. This membrane is coated on both sides with appropriate catalysts. Fuel is supplied to the anode, in this case a solution of methanol (methyl alcohol) is used. As a result of the chemical reaction of fuel decomposition, free charges are formed that penetrate through the membrane to the cathode. The electrical circuit is thus closed, and an electric current is created in it to power the device. This type of fuel cell is called the Direct Methanol Fuel Cell (DMFC). The development of fuel cells began a long time ago, but the first results, which gave reason to talk about real competition with lithium-ion batteries, were obtained only in the last two years.

In 2004, there were about 35 manufacturers on the market for such devices, but only a few companies were able to declare significant success in this area. In January, Fujitsu presented its development - the battery had a thickness of 15 mm and contained 300 mg of a 30% methanol solution. The power of 15 W allowed her to provide the laptop for 8 hours. A month later, a small company, PolyFuel, was the first to announce commercial production of the very membranes that fuel power supplies should be equipped with. And already in March, Toshiba demonstrated a prototype mobile PC that runs on fuel. The manufacturer claimed that such a laptop can last up to five times longer than a laptop using a traditional battery.

In 2005, LG Chem announced the creation of its fuel cell. About 5 years and 5 billion dollars were spent on its development. As a result, it was possible to create a device with a power of 25 W and a weight of 1 kg, connected to a laptop via a USB interface and ensuring its operation for 10 hours. This year, 2006, was also marked by a number of interesting developments. In particular, American developers from Ultracell demonstrated a fuel cell that provides 25 W of power and is equipped with three replaceable cartridges with 67% methanol. It is able to provide power to the laptop for 24 hours. The weight of the battery was about a kilogram, each cartridge weighed about 260 grams.

In addition to being able to provide more capacity than lithium ion batteries, methanol batteries are non-explosive. The disadvantages include their rather high cost and the need to periodically change methanol cartridges.

If fuel batteries do not replace traditional ones, then most likely they can be used in conjunction with them. According to experts, the market for fuel cells in 2006 will be about 600 million dollars, which is quite a modest figure. However, by 2010, experts predict a three-fold increase - up to 1.9 billion dollars.

Discussion of the article "Alcohol batteries replace lithium"

zemoneng

Fuck, I found information about this device in a women's magazine.
Well, let me say a few words about this:
1: the inconvenience is that after 6-10 hours of work, you will have to look for a new cartridge, and it is expensive. Why would I spend money on this nonsense
2: as far as I understand, after receiving energy from methyl alcohol, water should be released. A laptop and water are incompatible things.
3: why do you write in women's magazines? Judging by the comments "I don't know anything." and "What is this?", this article is not the level of a site dedicated to BEAUTY.

I insert the filler hose fitting into the fuel filler neck and turn it half a turn to seal the connection. A click of the toggle switch and the flashing of the LED on the filling station with a huge inscription h3 indicates that refueling has begun. A minute - and the tank is full, you can go!

Elegant body contours, ultra-low suspension, low-profile slicks give out a real racing breed. Through the transparent cover you can see the intricacies of pipelines and cables. Somewhere I have already seen a similar solution ... Oh yes, on the Audi R8, the engine is also visible through the rear window. But on Audi it is traditional gasoline, and this car runs on hydrogen. Like the BMW Hydrogen 7, but unlike the latter, there is no internal combustion engine here. The only moving parts are the steering gear and the rotor of the electric motor. And the energy for it is provided by a fuel cell. This car was released by the Singaporean company Horizon Fuel Cell Technologies, which specializes in the development and production of fuel cells. In 2009, the British company Riversimple already introduced an urban hydrogen car powered by Horizon Fuel Cell Technologies fuel cells. It was developed in collaboration with the Universities of Oxford and Cranfield. But Horizon H-racer 2.0 is a solo development.

The fuel cell consists of two porous electrodes coated with a catalyst layer and separated by a proton exchange membrane. Hydrogen on the anode catalyst is converted into protons and electrons, which through the anode and an external electrical circuit come to the cathode, where hydrogen and oxygen recombine to form water.

"Go!" - in Gagarin style, the editor-in-chief nudges me with his elbow. But not so fast: first you need to “warm up” the fuel cell at partial load. I switch the toggle switch to the “warm up” mode (“warming up”) and wait for the allotted time. Then, just in case, I top up the tank to the full. Now let's go: the machine, smoothly buzzing with the engine, moves forward. The dynamics are impressive, although, however, what else to expect from an electric car - the moment is constant at any speed. Although not for long - a full tank of hydrogen lasts only a few minutes (Horizon promises to release a new version in the near future, in which hydrogen is not stored as a pressurized gas, but is held by a porous material in an adsorber). Yes, and it is controlled, frankly, not very well - there are only two buttons on the remote control. But in any case, it's a pity that this is only a radio-controlled toy that cost us $150. We wouldn't mind driving a real fuel cell car as a power plant.

The tank, an elastic rubber container inside a rigid casing, stretches when refueling and works as a fuel pump, "squeezing" hydrogen into the fuel cell. In order not to "refill" the tank, one of the fittings is connected with a plastic tube to an emergency pressure relief valve.

Filling column

Do it yourself

The Horizon H-racer 2.0 comes as a SKD (do-it-yourself) kit, you can buy it, for example, on Amazon. However, it is not difficult to assemble it - just put the fuel cell in place and fix it with screws, connect the hoses to the hydrogen tank, fuel cell, filler neck and emergency valve, and all that remains is to put the upper body in place, not forgetting the front and rear bumpers. The kit comes with a filling station that receives hydrogen by electrolysis of water. It is powered by two AA batteries, and if you want the energy to be completely “clean” - from solar panels (they are also included).

www.popmech.ru

How to make a fuel cell with your own hands?

Of course, the simplest solution to the problem of ensuring the continuous operation of fuel-free systems is to purchase a ready-made secondary source of energy on a hydraulic or any other basis, but in this case it will certainly not be possible to avoid additional costs, and in this process it is quite difficult to consider any idea for flight of creative thought. In addition, making a fuel cell with your own hands is not at all as difficult as you might think at first glance, and if desired, even the most inexperienced master can cope with the task. In addition, a more than pleasant bonus will be the low costs for creating this element, because despite all its benefits and importance, it will be absolutely safe to get by with the available improvised means.

At the same time, the only nuance that must be taken into account before completing the task is that you can make an extremely low-power device with your own hands, and the implementation of more advanced and complex installations should still be left to qualified specialists. As for the order of work and the sequence of actions, first of all, the case should be completed, for which it is best to use thick-walled plexiglass (at least 5 centimeters). For gluing the walls of the case and mounting internal partitions, for which it is best to use thinner plexiglass (3 millimeters is enough), it is ideal to use two-composite glue, although with a strong desire, high-quality soldering can be done independently using the following proportions: per 100 grams of chloroform - 6 grams shavings from the same plexiglass.

In this case, the process must be carried out exclusively under the hood. In order to equip the case with the so-called drain system, it is necessary to carefully drill a through hole in its front wall, the diameter of which will exactly match the dimensions of the rubber stopper, which serves as a kind of gasket between the case and the glass drain tube. As for the dimensions of the tube itself, it is ideal to provide for its width equal to five or six millimeters, although it all depends on the type of structure being designed. It is more likely that the potential readers of this article will be somewhat surprised by the old gas mask listed in the list of necessary elements for making a fuel cell. Meanwhile, the whole benefit of this device lies in the activated carbon located in the compartments of his respirator, which can later be used as electrodes.

Since we are talking about a powdery consistency, to improve the design, you will need nylon stockings, from which you can easily make a bag and put coal there, otherwise it will simply spill out of the hole. As for the distribution function, the fuel is concentrated in the first chamber, while the oxygen necessary for the normal functioning of the fuel cell, on the contrary, will circulate in the last, fifth compartment. The electrolyte itself, located between the electrodes, should be impregnated with a special solution (gasoline with paraffin in a ratio of 125 to 2 milliliters), and this must be done even before the air electrolyte is placed in the fourth compartment. To ensure proper conductivity, copper plates with pre-soldered wires are laid on top of the coal, through which electricity will be transmitted from the electrodes.

This stage of design can be safely considered the final one, after which the finished device is charged, for which an electrolyte is needed. In order to prepare it, it is necessary to mix equal parts of ethyl alcohol with distilled water and proceed with the gradual introduction of caustic potassium at the rate of 70 grams per glass of liquid. The first test of the manufactured device consists in the simultaneous filling of the first (fuel liquid) and third (electrolyte made from ethyl alcohol and caustic potash) containers of the plexiglass body.

www.uznay-kak.ru

Hydrogen fuel cells | LAVENT

For a long time I wanted to tell you about another direction of the Alfaintek company. This is the development, sale and service of hydrogen fuel cells. I want to immediately explain the situation with these fuel cells in Russia.

Due to the rather high cost and the complete absence of hydrogen stations for charging these fuel cells, they are not expected to be sold in Russia. Nevertheless, in Europe, especially in Finland, these fuel cells are gaining popularity every year. What is the secret? Let's see. This device is environmentally friendly, easy to operate and efficient. It comes to the aid of a person where he needs electrical energy. You can take it with you on the road, on a hike, use it in the country, in the apartment as an autonomous source of electricity.

Electricity in a fuel cell is generated by the chemical reaction of hydrogen from a cylinder with metal hydride and oxygen from the air. The cylinder is not explosive and can be stored in your closet for years, waiting in the wings. This is, perhaps, one of the main advantages of this hydrogen storage technology. It is the storage of hydrogen that is one of the main problems in the development of hydrogen fuel. Unique new lightweight fuel cells that convert hydrogen into conventional electricity in a safe, quiet and emission-free manner.

This type of electricity can be used in places where there is no central electricity, or as an emergency power source.

Unlike conventional batteries, which need to be charged and at the same time disconnected from the consumer of electricity during the charging process, the fuel cell works as a “smart” device. This technology provides uninterrupted power throughout the entire period of use due to the unique function of maintaining power when changing the fuel tank, which allows the user to never turn off the consumer. In a closed case, fuel cells can be stored for several years without losing hydrogen and reducing their power.

The fuel cell is designed for scientists and researchers, law enforcement, lifeguards, ship and marina owners, and anyone who needs a reliable power source in case of emergency. You can get a voltage of 12 volts or 220 volts and then you will have enough energy to use a TV, stereo system, refrigerator, coffee maker, kettle, vacuum cleaner, drill, micro stove and other electrical appliances.

Hydrocell fuel cells can be sold as a single unit or as batteries of 2-4 cells. Two or four elements can be combined to either increase power or increase current.

OPERATING TIME OF HOUSEHOLD APPLIANCES WITH FUEL CELLS

* - continuous work

Fuel cells are fully charged at special hydrogen stations. But what if you are traveling far away from them and there is no way to recharge? Especially for such cases, Alfaintek specialists have developed cylinders for storing hydrogen, with which fuel cells will work much longer.

Two types of cylinders are produced: NS-MN200 and NS-MN1200. The assembled NS-MN200 has a size slightly larger than a Coca-Cola can, it holds 230 liters of hydrogen, which corresponds to 40Ah (12V), and weighs only 2.5 kg .Cylinder with metal hydride NS-MH1200 holds 1200 liters of hydrogen, which corresponds to 220Ah (12V). The weight of the cylinder is 11 kg.

The metal hydride technique is a safe and easy way to store, transport and use hydrogen. When stored as a metal hydride, hydrogen is in the form of a chemical compound rather than in gaseous form. This method makes it possible to obtain a sufficiently high energy density. The advantage of using metal hydride is that the pressure inside the cylinder is only 2-4 bar. The cylinder is not explosive and can be stored for years without reducing the volume of the substance. Since the hydrogen is stored as a metal hydride, the purity of the hydrogen obtained from the cylinder is very high, 99.999%. Hydrogen storage cylinders in the form of metal hydride can be used not only with HC 100,200,400 fuel cells, but also in other cases where pure hydrogen is needed. Cylinders can be easily connected to a fuel cell or other device with a quick connect connector and flexible hose.

It is a pity that these fuel cells are not sold in Russia. But among our population there are so many people who need them. Well, let's wait and see, you look and we will have. In the meantime, we will buy energy-saving light bulbs imposed by the state.

P.S. It seems that the topic has finally gone into oblivion. So many years after this article was written, nothing came out. Maybe, of course, I'm not looking everywhere, but what catches my eye is not at all pleasing. The technology and the idea is good, but the development has not yet been found.

lavent.ru

The fuel cell is the future that starts today!

The beginning of the 21st century considers ecology as one of the most important world tasks. And the first thing that should be paid attention to under the current conditions is the search for and use of alternative energy sources. It is they who are able to prevent pollution of the environment around us, as well as completely abandon the continuously rising cost of hydrocarbon-based fuel.

Already today, energy sources such as solar cells and wind turbines have been used. But, unfortunately, their lack is associated with dependence on the weather, as well as on the season and time of day. For this reason, their use in astronautics, aircraft and automotive industries is gradually abandoned, and for stationary use they are equipped with secondary power sources - batteries.

However, the best solution is a fuel cell, as it does not require constant energy recharging. This is a device that is capable of processing and converting various types of fuel (gasoline, alcohol, hydrogen, etc.) directly into electrical energy.

The fuel cell works according to the following principle: fuel is supplied from the outside, which is oxidized by oxygen, and the energy released in this case is converted into electricity. This principle of operation ensures almost eternal operation.

Starting from the end of the 19th century, scientists studied the fuel cell directly, and constantly developed new modifications of it. So, today, depending on the operating conditions, there are alkaline or alkaline (AFC), direct borohydrate (DBFC), electro-galvanic (EGFC), direct methanol (DMFC), zinc-air (ZAFC), microbial (MFC), formic acid (DFAFC) and metal hydride (MHFC) models are also known.

One of the most promising is the hydrogen fuel cell. The use of hydrogen in power plants is accompanied by a significant release of energy, and the exhaust of such a device is pure water vapor or drinking water, which does not pose any threat to the environment.

The successful testing of fuel cells of this type on spacecraft has recently aroused considerable interest among manufacturers of electronics and various equipment. For example, PolyFuel introduced a miniature hydrogen fuel cell for laptops. But the too high cost of such a device and the difficulty in its unhindered refueling limits industrial production and wide distribution. Honda has also been producing automotive fuel cells for over 10 years. However, this type of transport does not go on sale, but only for the official use of company employees. Cars are under the supervision of engineers.

Many are wondering if it is possible to assemble a fuel cell with your own hands. After all, a significant advantage of a home-made device will be a small investment, in contrast to the industrial model. For a miniature model, you will need 30 cm of platinum-plated nickel wire, a small piece of plastic or wood, a clip for a 9-volt battery and the battery itself, transparent adhesive tape, a glass of water and a voltmeter. Such a device will allow you to see and understand the essence of the work, but, of course, it will not work to generate electricity for the car.

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Hydrogen fuel cells: a bit of history | Hydrogen

In our time, the problem of the shortage of traditional energy resources and the deterioration of the planet's ecology as a whole due to their use is especially acute. That is why, in recent years, significant financial and intellectual resources have been spent on the development of potentially promising substitutes for hydrocarbon fuels. Hydrogen can become such a substitute in the very near future, since its use in power plants is accompanied by the release of a large amount of energy, and the exhausts are water vapor, that is, they do not pose a danger to the environment.

Despite some technical difficulties that still exist in introducing hydrogen-based fuel cells, many car manufacturers have appreciated the promise of the technology and are already actively developing prototypes of mass-produced vehicles capable of using hydrogen as the main fuel. Back in 2011, Daimler AG introduced conceptual Mercedes-Benz models with hydrogen power plants. In addition, the Korean company Hyndayi has officially announced that it does not intend to develop electric cars anymore, and will concentrate all efforts on developing an affordable hydrogen car.

Although the idea of ​​using hydrogen as a fuel is not wild for many, most do not understand how hydrogen fuel cells work and what is so remarkable about them.

To understand the importance of the technology, we suggest turning to the history of hydrogen fuel cells.

The first person to describe the potential of using hydrogen in a fuel cell was Christian Friedrich, a German. Back in 1838, he published his work in a well-known scientific journal of that time.

The very next year, a judge from Ouls, Sir William Robert Grove, created a prototype of a workable hydrogen battery. However, the power of the device was too small even by the standards of that time, so there was no question of its practical use.

As for the term "fuel cell", it owes its existence to the scientists Ludwig Mond and Charles Langer, who in 1889 attempted to create a fuel cell operating on air and coke oven gas. According to others, the term was first used by William White Jaques, who first decided to use phosphoric acid in the electrolyte.

In the 1920s, a number of studies were carried out in Germany, the result of which was the discovery of solid oxide fuel cells and ways to use the carbonate cycle. It is noteworthy that these technologies are effectively used in our time.

In 1932, engineer Francis T Bacon began work on the study of directly fuel cells based on hydrogen. Before him, scientists used an established scheme - porous platinum electrodes were placed in sulfuric acid. The obvious disadvantage of such a scheme lies, first of all, in its unjustified high cost due to the use of platinum. In addition, the use of caustic sulfuric acid posed a threat to the health, and sometimes life, of researchers. Bacon decided to optimize the circuit and replaced the platinum with nickel, and used an alkaline composition as the electrolyte.

Thanks to the productive work to improve his technology, Bacon already in 1959 presented to the general public his original hydrogen fuel cell, which produced 5 kW and could power a welding machine. He called the presented device "Bacon Cell".

In October of the same year, a unique tractor was created that ran on hydrogen and produced twenty horsepower.

In the sixties of the twentieth century, the American company General Electric, the scheme developed by Bacon, was improved and applied to the Apollo and NASA Gemini space programs. Specialists from NASA came to the conclusion that the use of a nuclear reactor is too expensive, technically difficult and unsafe. In addition, it was necessary to abandon the use of batteries with solar panels due to their large dimensions. The solution to the problem was hydrogen fuel cells, which are able to supply the spacecraft with energy, and its crew with clean water.

The first bus using hydrogen as fuel was built in 1993. And prototypes of passenger cars powered by hydrogen fuel cells were already presented in 1997 by such global automotive brands as Toyota and Daimler Benz.

It is a little strange that a promising environmentally friendly fuel, implemented fifteen years ago in a car, has not yet become widespread. There are many reasons for this, the main of which, perhaps, are political and exactingness in the creation of an appropriate infrastructure. Let's hope that hydrogen will still have its say and will be a significant competitor to electric cars. (odnaknopka)

energycraft.org

Our material society without energy cannot not only develop, but even exist in general. Where does energy come from? Until recently, people used only one way to get it, we fought with nature, burning the extracted trophies in the fireboxes, first at home, then in steam locomotives and powerful thermal power plants.

There are no labels on the kilowatt-hours consumed by a modern layman that would indicate how many years nature has worked so that a civilized person can enjoy the benefits of technology, and how many years she still has to work to mitigate the harm caused to her by such a civilization. However, the understanding is ripening in society that sooner or later the illusory idyll will end. Increasingly, people are inventing ways to provide energy for their needs with minimal damage to nature.

Hydrogen fuel cells are the holy grail of clean energy. They process hydrogen, one of the common elements of the periodic table, and emit only water, the most common substance on the planet. The rosy picture is spoiled by the lack of access for people to hydrogen as a substance. There is a lot of it, but only in a bound state, and it is much more difficult to extract it than to pump oil out of the bowels or dig out coal.

One of the options for clean and environmentally friendly hydrogen production is microbial fuel cells (MTBs), which use microorganisms to decompose water into oxygen and hydrogen. Here, too, not everything is smooth. Microbes do an excellent job of producing clean fuel, but to achieve the efficiency required in practice, MTB needs a catalyst that accelerates one of the chemical reactions of the process.

This catalyst is the precious metal platinum, the cost of which makes the use of MTB economically unjustified and practically impossible.

Scientists from the University of Wisconsin-Milwaukee have found a replacement for an expensive catalyst. Instead of platinum, they proposed using cheap nanorods made from a combination of carbon, nitrogen, and iron. The new catalyst consists of graphite rods with nitrogen introduced into the surface layer and iron carbide cores. During the three-month testing of the novelty, the catalyst demonstrated higher capabilities than those of platinum. The operation of nanorods turned out to be more stable and controllable.

And most importantly, the brainchild of university scientists is much cheaper. Thus, the cost of platinum catalysts is approximately 60% of the cost of MTB, while the cost of nanorods is 5% of their current price.

According to the creator of catalytic nanorods, Professor Yuhong Chen (Junhong Chen): “Fuel cells are able to directly convert fuel into electricity. Together with them, electricity from renewable sources can be delivered to where it is needed, which is clean, efficient and sustainable.”

Now Professor Chen and his team of researchers are busy studying the exact characteristics of the catalyst. Their goal is to give their invention a practical focus, to make it suitable for mass production and use.

According to Gizmag

www.facepla.net

Hydrogen fuel cells and energy systems

The water-powered car may soon become a reality and hydrogen fuel cells will be installed in many homes...

Hydrogen fuel cell technology is not new. It began in 1776 when Henry Cavendish first discovered hydrogen while dissolving metals in dilute acids. The first hydrogen fuel cell was invented as early as 1839 by William Grove. Since then, hydrogen fuel cells have been gradually improved and are now installed in space shuttles, supplying them with energy and serving as a source of water. Today, hydrogen fuel cell technology is on the verge of reaching the mass market, in cars, homes and portable devices.

In a hydrogen fuel cell, chemical energy (in the form of hydrogen and oxygen) is converted directly (without combustion) into electrical energy. The fuel cell consists of a cathode, electrodes and an anode. Hydrogen is fed to the anode, where it is split into protons and electrons. Protons and electrons have different routes to the cathode. The protons travel through the electrode to the cathode, and the electrons travel around the fuel cells to get to the cathode. This movement creates subsequently usable electrical energy. On the other side, hydrogen protons and electrons combine with oxygen to form water.

Electrolyzers are one way to extract hydrogen from water. The process is basically the opposite of what happens when a hydrogen fuel cell operates. The electrolyzer consists of an anode, an electrochemical cell and a cathode. Water and voltage are applied to the anode, which splits the water into hydrogen and oxygen. Hydrogen passes through the electrochemical cell to the cathode and oxygen is fed directly to the cathode. From there, hydrogen and oxygen can be extracted and stored. During times when electricity is not required to be produced, the accumulated gas can be drawn out of the storage and passed back through the fuel cell.

This system uses hydrogen as fuel, which is probably why there are many myths about its safety. After the explosion of the Hindenburg, many people far from science and even some scientists began to believe that the use of hydrogen is very dangerous. However, recent research has shown that the cause of this tragedy was due to the type of material that was used in the construction, and not to the hydrogen that was pumped inside. After conducting tests on the safety of hydrogen storage, it was found that storing hydrogen in fuel cells is safer than storing gasoline in a car fuel tank.

How much do modern hydrogen fuel cells cost? Companies are currently offering hydrogen fuel systems to produce power for about $3,000 per kilowatt. Market research has established that when the cost drops to $1,500 per kilowatt, consumers in the mass energy market will be ready to switch to this type of fuel.

Hydrogen fuel cell vehicles are still more expensive than internal combustion engine vehicles, but manufacturers are exploring ways to bring the price up to a comparable level. In some remote areas where there are no power lines, using hydrogen as a fuel or autonomous power supply at home may be more economical now than, for example, building infrastructure for traditional energy carriers.

Why are hydrogen fuel cells still not widely used? At the moment, their high cost is the main problem for the distribution of hydrogen fuel cells. Hydrogen fuel systems simply do not have mass demand at the moment. However, science does not stand still and in the near future a car running on water can become a real reality.

www.tesla-tehnika.biz

The water-powered car may soon become a reality and hydrogen fuel cells will be installed in many homes...

Hydrogen technology fuel cells not new. It began in 1776 when Henry Cavendish first discovered hydrogen while dissolving metals in dilute acids. The first hydrogen fuel cell was invented as early as 1839 by William Grove. Since then, hydrogen fuel cells have been gradually improved and are now installed in space shuttles, supplying them with energy and serving as a source of water. Today, hydrogen fuel cell technology is on the verge of reaching the mass market, in cars, homes and portable devices.

In a hydrogen fuel cell, chemical energy (in the form of hydrogen and oxygen) is converted directly (without combustion) into electrical energy. The fuel cell consists of a cathode, electrodes and an anode. Hydrogen is fed to the anode, where it is split into protons and electrons. Protons and electrons have different routes to the cathode. The protons travel through the electrode to the cathode, and the electrons travel around the fuel cells to get to the cathode. This movement creates subsequently usable electrical energy. On the other side, hydrogen protons and electrons combine with oxygen to form water.

Electrolyzers are one way to extract hydrogen from water. The process is basically the opposite of what happens when a hydrogen fuel cell operates. The electrolyzer consists of an anode, an electrochemical cell and a cathode. Water and voltage are applied to the anode, which splits the water into hydrogen and oxygen. Hydrogen passes through the electrochemical cell to the cathode and oxygen is fed directly to the cathode. From there, hydrogen and oxygen can be extracted and stored. During times when electricity is not required to be produced, the accumulated gas can be drawn out of the storage and passed back through the fuel cell.

This system uses hydrogen as fuel, which is probably why there are many myths about its safety. After the explosion of the Hindenburg, many people far from science and even some scientists began to believe that the use of hydrogen is very dangerous. However, recent research has shown that the cause of this tragedy was due to the type of material that was used in the construction, and not to the hydrogen that was pumped inside. After testing the safety of hydrogen storage, it was found that hydrogen storage in fuel cells is safer than storing gasoline in a car's fuel tank.

How much do modern hydrogen fuel cells cost?? Companies are currently offering hydrogen fuel systems producing energy at a cost of about $ 3,000 per kilowatt. Market research has established that when the cost drops to $1,500 per kilowatt, consumers in the mass energy market will be ready to switch to this type of fuel.

Hydrogen fuel cell vehicles are still more expensive than internal combustion engine vehicles, but manufacturers are exploring ways to bring the price up to a comparable level. In some remote areas where there are no power lines, using hydrogen as a fuel or autonomous power supply at home may be more economical now than, for example, building infrastructure for traditional energy carriers.

Why are hydrogen fuel cells still not widely used? At the moment, their high cost is the main problem for the distribution of hydrogen fuel cells. Hydrogen fuel systems simply do not have mass demand at the moment. However, science does not stand still and in the near future a car running on water can become a real reality.

Fabrication, assembly, testing and testing of fuel (hydrogen) cells/cells
Manufactured in factories in the US and Canada

Fuel (hydrogen) cells/cells

The company Intech GmbH / LLC Intech GmbH has been on the market of engineering services since 1997, the official for many years of various industrial equipment, brings to your attention various fuel (hydrogen) cells / cells.

A fuel cell/cell is

Benefits of fuel cells/cells

A fuel cell/cell is a device that efficiently generates direct current and heat from a hydrogen-rich fuel through an electrochemical reaction.

A fuel cell is similar to a battery in that it generates direct current through a chemical reaction. The fuel cell includes an anode, a cathode and an electrolyte. However, unlike batteries, fuel cells/cells cannot store electrical energy, do not discharge, and do not require electricity to be recharged. Fuel cells/cells can continuously generate electricity as long as they have a supply of fuel and air.

Unlike other power generators such as internal combustion engines or turbines powered by gas, coal, oil, etc., fuel cells/cells do not burn fuel. This means no noisy high pressure rotors, no loud exhaust noise, no vibration. Fuel cells/cells generate electricity through a silent electrochemical reaction. Another feature of fuel cells/cells is that they convert the chemical energy of the fuel directly into electricity, heat and water.

Fuel cells are highly efficient and do not produce large amounts of greenhouse gases such as carbon dioxide, methane and nitrous oxide. The only products emitted during operation are water in the form of steam and a small amount of carbon dioxide, which is not emitted at all if pure hydrogen is used as fuel. Fuel cells/cells are assembled into assemblies and then into individual functional modules.

History of fuel cell/cell development

In the 1950s and 1960s, one of the biggest challenges for fuel cells was born out of the US National Aeronautics and Space Administration's (NASA) need for energy sources for long-duration space missions. NASA's Alkaline Fuel Cell/Cell uses hydrogen and oxygen as fuel, combining the two in an electrochemical reaction. The output is three by-products of the reaction useful in spaceflight - electricity to power the spacecraft, water for drinking and cooling systems, and heat to keep the astronauts warm.

The discovery of fuel cells dates back to the beginning of the 19th century. The first evidence of the effect of fuel cells was obtained in 1838.

In the late 1930s, work began on alkaline fuel cells, and by 1939 a cell using high pressure nickel-plated electrodes had been built. During the Second World War, fuel cells/cells for British Navy submarines were developed and in 1958 a fuel assembly consisting of alkaline fuel cells/cells just over 25 cm in diameter was introduced.

Interest increased in the 1950s and 1960s and also in the 1980s when the industrial world experienced a shortage of fuel oil. In the same period, world countries also became concerned about the problem of air pollution and considered ways to generate environmentally friendly electricity. At present, fuel cell/cell technology is undergoing rapid development.

How fuel cells/cells work

Fuel cells/cells generate electricity and heat through an ongoing electrochemical reaction using an electrolyte, a cathode and an anode.

The anode and cathode are separated by an electrolyte that conducts protons. After hydrogen enters the anode, and oxygen enters the cathode, a chemical reaction begins, as a result of which electricity, heat and water.

On the anode catalyst, molecular hydrogen dissociates and loses electrons. Hydrogen ions (protons) are conducted through the electrolyte to the cathode, while electrons are passed through the electrolyte and pass through the outer electrical circuit, creating a direct current that can be used to power equipment. On the cathode catalyst, an oxygen molecule combines with an electron (which is supplied from external communications) and an incoming proton, and forms water, which is the only reaction product (in the form of vapor and / or liquid).

Below is the corresponding reaction:

Anode reaction: 2H 2 => 4H+ + 4e -
Reaction at the cathode: O 2 + 4H+ + 4e - => 2H 2 O
General element reaction: 2H 2 + O 2 => 2H 2 O

Types and variety of fuel cells/cells

Similar to the existence of different types of internal combustion engines, there are different types of fuel cells - the choice of the appropriate type of fuel cell depends on its application.

Fuel cells are divided into high temperature and low temperature. Low temperature fuel cells require relatively pure hydrogen as fuel. This often means that fuel processing is required to convert the primary fuel (such as natural gas) to pure hydrogen. This process consumes additional energy and requires special equipment. High temperature fuel cells do not need this additional procedure, as they can "internally convert" the fuel at elevated temperatures, which means there is no need to invest in hydrogen infrastructure.

Fuel cells/cells on molten carbonate (MCFC)

Molten carbonate electrolyte fuel cells are high temperature fuel cells. The high operating temperature allows direct use of natural gas without a fuel processor and fuel gas with low calorific value fuel production processes and from other sources.

The operation of RCFC is different from other fuel cells. These cells use an electrolyte from a mixture of molten carbonate salts. Currently, two types of mixtures are used: lithium carbonate and potassium carbonate or lithium carbonate and sodium carbonate. To melt carbonate salts and achieve a high degree of mobility of ions in the electrolyte, fuel cells with molten carbonate electrolyte operate at high temperatures (650°C). The efficiency varies between 60-80%.

When heated to a temperature of 650°C, salts become a conductor for carbonate ions (CO 3 2-). These ions pass from the cathode to the anode where they combine with hydrogen to form water, carbon dioxide and free electrons. These electrons are sent through an external electrical circuit back to the cathode, generating electrical current and heat as a by-product.

Anode reaction: CO 3 2- + H 2 => H 2 O + CO 2 + 2e -
Reaction at the cathode: CO 2 + 1/2O 2 + 2e - => CO 3 2-
General element reaction: H 2 (g) + 1/2O 2 (g) + CO 2 (cathode) => H 2 O (g) + CO 2 (anode)

The high operating temperatures of molten carbonate electrolyte fuel cells have certain advantages. At high temperatures, internal reforming occurs natural gas, which eliminates the need for a fuel processor. In addition, the advantages include the ability to use standard materials of construction, such as stainless steel sheet and nickel catalyst on the electrodes. The waste heat can be used to generate high pressure steam for various industrial and commercial purposes.

High reaction temperatures in the electrolyte also have their advantages. The use of high temperatures takes a long time to reach optimal operating conditions, and the system reacts more slowly to changes in energy consumption. These characteristics allow the use of fuel cell systems with molten carbonate electrolyte in constant power conditions. High temperatures prevent damage to the fuel cell by carbon monoxide.

Molten carbonate fuel cells are suitable for use in large stationary installations. Thermal power plants with an output electric power of 3.0 MW are industrially produced. Plants with an output power of up to 110 MW are being developed.

Fuel cells/cells based on phosphoric acid (PFC)

Fuel cells based on phosphoric (orthophosphoric) acid were the first fuel cells for commercial use.

Fuel cells based on phosphoric (orthophosphoric) acid use an electrolyte based on orthophosphoric acid (H 3 PO 4) with a concentration of up to 100%. The ionic conductivity of phosphoric acid is low at low temperatures, for this reason these fuel cells are used at temperatures up to 150–220°C.

The charge carrier in fuel cells of this type is hydrogen (H+, proton). A similar process occurs in proton exchange membrane fuel cells, in which hydrogen supplied to the anode is split into protons and electrons. The protons pass through the electrolyte and combine with oxygen from the air at the cathode to form water. The electrons are directed along an external electrical circuit, and an electric current is generated. Below are the reactions that generate electricity and heat.

Reaction at the anode: 2H 2 => 4H + + 4e -
Reaction at the cathode: O 2 (g) + 4H + + 4e - \u003d\u003e 2 H 2 O
General element reaction: 2H 2 + O 2 => 2H 2 O

The efficiency of fuel cells based on phosphoric (orthophosphoric) acid is more than 40% when generating electrical energy. In the combined production of heat and electricity, the overall efficiency is about 85%. In addition, given operating temperatures, waste heat can be used to heat water and generate steam at atmospheric pressure.

The high performance of thermal power plants on fuel cells based on phosphoric (orthophosphoric) acid in the combined production of heat and electricity is one of the advantages of this type of fuel cells. The plants use carbon monoxide at a concentration of about 1.5%, which greatly expands the choice of fuel. In addition, CO 2 does not affect the electrolyte and the operation of the fuel cell, this type of cell works with reformed natural fuel. Simple construction, low electrolyte volatility and increased stability are also advantages of this type of fuel cell.

Thermal power plants with an output electric power of up to 500 kW are industrially produced. Installations for 11 MW have passed the relevant tests. Plants with an output power of up to 100 MW are being developed.

Solid oxide fuel cells/cells (SOFC)

Solid oxide fuel cells are the fuel cells with the highest operating temperature. The operating temperature can vary from 600°C to 1000°C, which allows the use of various types of fuel without special pre-treatment. To handle these high temperatures, the electrolyte used is a thin ceramic-based solid metal oxide, often an alloy of yttrium and zirconium, which is a conductor of oxygen (O 2-) ions.

A solid electrolyte provides a hermetic gas transition from one electrode to another, while liquid electrolytes are located in a porous substrate. The charge carrier in fuel cells of this type is the oxygen ion (O 2-). At the cathode, oxygen molecules are separated from the air into an oxygen ion and four electrons. Oxygen ions pass through the electrolyte and combine with hydrogen to form four free electrons. Electrons are directed through an external electrical circuit, generating electrical current and waste heat.

Reaction at the anode: 2H 2 + 2O 2- => 2H 2 O + 4e -
Reaction at the cathode: O 2 + 4e - \u003d\u003e 2O 2-
General element reaction: 2H 2 + O 2 => 2H 2 O

The efficiency of the generated electrical energy is the highest of all fuel cells - about 60-70%. High operating temperatures allow for combined heat and power generation to generate high pressure steam. Combining a high temperature fuel cell with a turbine creates a hybrid fuel cell to increase the efficiency of power generation up to 75%.

Solid oxide fuel cells operate at very high temperatures (600°C-1000°C), resulting in a long time to reach optimal operating conditions, and the system is slower to respond to changes in power consumption. At such high operating temperatures, no converter is required to recover hydrogen from the fuel, allowing the thermal power plant to operate with relatively impure fuels from coal gasification or waste gases, and the like. Also, this fuel cell is excellent for high power applications, including industrial and large central power plants. Industrially produced modules with an output electrical power of 100 kW.

Fuel cells/cells with direct methanol oxidation (DOMTE)

The technology of using fuel cells with direct oxidation of methanol is undergoing a period of active development. It has successfully established itself in the field of powering mobile phones, laptops, as well as for creating portable power sources. what the future application of these elements is aimed at.

The structure of fuel cells with direct oxidation of methanol is similar to fuel cells with a proton exchange membrane (MOFEC), i.e. a polymer is used as an electrolyte, and a hydrogen ion (proton) is used as a charge carrier. However, liquid methanol (CH 3 OH) is oxidized in the presence of water at the anode, releasing CO 2 , hydrogen ions and electrons, which are guided through an external electrical circuit, and an electric current is generated. Hydrogen ions pass through the electrolyte and react with oxygen from the air and electrons from the external circuit to form water at the anode.

Reaction at the anode: CH 3 OH + H 2 O => CO 2 + 6H + + 6e -
Reaction at the cathode: 3/2O 2 + 6 H + + 6e - => 3H 2 O
General element reaction: CH 3 OH + 3/2O 2 => CO 2 + 2H 2 O

The advantage of this type of fuel cells is their small size, due to the use of liquid fuel, and the absence of the need to use a converter.

Alkaline fuel cells/cells (AFC)

Alkaline fuel cells are one of the most efficient elements used to generate electricity, with power generation efficiency reaching up to 70%.

Alkaline fuel cells use an electrolyte, i.e. an aqueous solution of potassium hydroxide, contained in a porous, stabilized matrix. The concentration of potassium hydroxide may vary depending on the operating temperature of the fuel cell, which ranges from 65°C to 220°C. The charge carrier in an SFC is a hydroxide ion (OH-) moving from the cathode to the anode where it reacts with hydrogen to produce water and electrons. The water produced at the anode moves back to the cathode, again generating hydroxide ions there. As a result of this series of reactions taking place in the fuel cell, electricity is produced and, as a by-product, heat:

Reaction at the anode: 2H 2 + 4OH - => 4H 2 O + 4e -
Reaction at the cathode: O 2 + 2H 2 O + 4e - => 4 OH -
General reaction of the system: 2H 2 + O 2 => 2H 2 O

The advantage of SFCs is that these fuel cells are the cheapest to produce, since the catalyst needed on the electrodes can be any of the substances that are cheaper than those used as catalysts for other fuel cells. SCFCs operate at relatively low temperatures and are among the most efficient fuel cells - such characteristics can respectively contribute to faster power generation and high fuel efficiency.

One of the characteristic features of SHTE is its high sensitivity to CO 2 , which can be contained in fuel or air. CO 2 reacts with the electrolyte, quickly poisons it, and greatly reduces the efficiency of the fuel cell. Therefore, the use of SFCs is limited to closed spaces such as space and underwater vehicles, they must operate on pure hydrogen and oxygen. Moreover, molecules such as CO, H 2 O and CH4, which are safe for other fuel cells and even fuel for some of them, are detrimental to SFCs.

Polymer electrolyte fuel cells/cells (PETE)

In the case of polymer electrolyte fuel cells, the polymer membrane consists of polymer fibers with water regions in which there is a conduction of water ions (H 2 O + (proton, red) attached to the water molecule). Water molecules present a problem due to slow ion exchange. Therefore, a high concentration of water is required both in the fuel and on the exhaust electrodes, which limits the operating temperature to 100°C.

Solid acid fuel cells/cells (SCFC)

In solid acid fuel cells, the electrolyte (CsHSO 4 ) does not contain water. The operating temperature is therefore 100-300°C. The rotation of the SO 4 2- oxy anions allows the protons (red) to move as shown in the figure. Typically, a solid acid fuel cell is a sandwich in which a very thin layer of solid acid compound is sandwiched between two tightly compressed electrodes to ensure good contact. When heated, the organic component evaporates, leaving through the pores in the electrodes, retaining the ability of numerous contacts between the fuel (or oxygen at the other end of the cell), electrolyte and electrodes.

Innovative energy-saving municipal heat and power plants are typically built on solid oxide fuel cells (SOFCs), polymer electrolyte fuel cells (PEFCs), phosphoric acid fuel cells (PCFCs), proton exchange membrane fuel cells (MPFCs) and alkaline fuel cells (APFCs) . They usually have the following characteristics:

Solid oxide fuel cells (SOFC) should be recognized as the most suitable, which:

• operate at a higher temperature, which reduces the need for expensive precious metals (such as platinum)
• can work for various types hydrocarbon fuels, mainly natural gas
• have a longer start-up time and therefore are better suited for long-term operation
• demonstrate high efficiency of power generation (up to 70%)
• due to high operating temperatures, the units can be combined with heat recovery systems, bringing the overall system efficiency up to 85%
• have near-zero emissions, operate silently and have low operating requirements compared to existing power generation technologies

Since small thermal power plants can be connected to a conventional gas supply network, fuel cells do not require separate system supply of hydrogen. When using small thermal power plants based on solid oxide fuel cells, the generated heat can be integrated into heat exchangers for heating water and ventilation air, increasing the overall efficiency of the system. This innovative technology is best suited for efficient power generation without the need for expensive infrastructure and complex instrument integration.

Fuel cell/cell applications

Application of fuel cells/cells in telecommunication systems

With the rapid spread of wireless communication systems around the world, as well as the growing social and economic benefits of mobile phone technology, the need for reliable and cost-effective backup power has become critical. Grid losses throughout the year due to bad weather, natural disasters or limited grid capacity are a constant challenge for grid operators.

Traditional telecom power backup solutions include batteries (valve-regulated lead-acid battery cell) for short-term backup power and diesel and propane generators for longer backup power. Batteries are a relatively cheap source of backup power for 1 to 2 hours. However, batteries are not suitable for longer backup periods because they are expensive to maintain, become unreliable after long use, are sensitive to temperatures, and are hazardous to the environment after disposal. Diesel and propane generators can provide continuous backup power. However, generators can be unreliable, require extensive maintenance, and release high levels of pollutants and greenhouse gases into the atmosphere.

In order to eliminate the limitations of traditional backup power solutions, an innovative green fuel cell technology has been developed. Fuel cells are reliable, quiet, contain fewer moving parts than a generator, have a wider operating temperature range than a battery from -40°C to +50°C and, as a result, provide extremely high levels of energy savings. In addition, the lifetime cost of such a plant is lower than that of a generator. Lower fuel cell costs are the result of only one maintenance visit per year and significantly higher plant productivity. After all, the fuel cell is an environmentally friendly technology solution with minimal environmental impact.

Fuel cell units provide backup power for critical communications network infrastructures for wireless, permanent and broadband communications in the telecommunications system, ranging from 250W to 15kW, they offer many unrivaled innovative features:

• RELIABILITY– Few moving parts and no standby discharge
• ENERGY SAVING
• SILENCE– low noise level
• STABILITY– operating range from -40°C to +50°C
• ADAPTABILITY– outdoor and indoor installation (container/protective container)
• HIGH POWER– up to 15 kW
• LOW MAINTENANCE NEED– minimum annual maintenance
• ECONOMY- attractive total cost of ownership
• CLEAN ENERGY– low emissions with minimal environmental impact

The system senses the DC bus voltage all the time and smoothly accepts critical loads if the DC bus voltage drops below a user-defined setpoint. The system runs on hydrogen, which enters the fuel cell stack in one of two ways - either from a commercial source of hydrogen, or from a liquid fuel of methanol and water, using an on-board reformer system.

Electricity is produced by the fuel cell stack in the form of direct current. The DC power is sent to a converter that converts the unregulated DC power from the fuel cell stack into high quality, regulated DC power for the required loads. A fuel cell installation can provide backup power for many days, as the duration is limited only by the amount of hydrogen or methanol/water fuel available in stock.

Fuel cells offer superior energy efficiency, increased system reliability, more predictable performance in a wide range of climates, and reliable service life compared to industry standard valve regulated lead acid battery packs. Lifecycle costs are also lower due to significantly less maintenance and replacement requirements. Fuel cells offer the end user environmental benefits as disposal costs and liability risks associated with lead acid cells are a growing concern.

The performance of electric batteries can be adversely affected by a wide range of factors such as charge level, temperature, cycles, life and other variables. The energy provided will vary depending on these factors and is not easy to predict. The performance of a proton exchange membrane fuel cell (PEMFC) is relatively unaffected by these factors and can provide critical power as long as fuel is available. Increased predictability is an important benefit when moving to fuel cells for mission-critical backup power applications.

Fuel cells generate energy only when fuel is supplied, like a gas turbine generator, but do not have moving parts in the generation zone. Therefore, unlike a generator, they are not subject to rapid wear and do not require constant maintenance and lubrication.

The fuel used to drive the Extended Duration Fuel Converter is a mixture of methanol and water. Methanol is a widely available, commercial fuel that currently has many uses, including windshield washer, plastic bottles, engine additives, and emulsion paints. Methanol is easy to transport, miscible with water, has good biodegradability and is sulfur free. It has a low freezing point (-71°C) and does not decompose during long storage.

Application of fuel cells/cells in communication networks

Security networks require reliable backup power solutions that can last for hours or days in an emergency if the power grid becomes unavailable.

With few moving parts and no standby power reduction, the innovative fuel cell technology offers an attractive solution compared to currently available backup power systems.

The most compelling reason for using fuel cell technology in communications networks is the increased overall reliability and security. During events such as power outages, earthquakes, storms, and hurricanes, it is important that systems continue to operate and have a reliable backup power supply for an extended period of time, regardless of the temperature or age of the backup power system.

The range of fuel cell power supplies is ideal for supporting secure communications networks. Thanks to their energy saving design principles, they provide an environmentally friendly, reliable backup power with extended duration (up to several days) for use in the power range from 250 W to 15 kW.

Application of fuel cells/cells in data networks

Reliable power supply for data networks, such as high-speed data networks and fiber optic backbones, is of key importance throughout the world. Information transmitted over such networks contains critical data for institutions such as banks, airlines or medical centers. A power outage in such networks not only poses a danger to the transmitted information, but also, as a rule, leads to significant financial losses. Reliable, innovative fuel cell installations that provide standby power provide the reliability you need to ensure uninterrupted power.

Fuel cell units operating on a liquid fuel mixture of methanol and water provide a reliable backup power supply with extended duration, up to several days. In addition, these units feature significantly reduced maintenance requirements compared to generators and batteries, requiring only one maintenance visit per year.

Typical application characteristics for the use of fuel cell installations in data networks:

• Applications with power inputs from 100 W to 15 kW
• Applications with battery life requirements > 4 hours
• Repeaters in fiber optic systems (hierarchy of synchronous digital systems, high speed internet, voice over IP…)
• Network nodes of high-speed data transmission
• WiMAX Transmission Nodes

Fuel cell standby installations offer numerous advantages for critical data network infrastructures over traditional battery or diesel generators, allowing for increased on-site utilization:

1. Liquid fuel technology solves the problem of hydrogen storage and provides virtually unlimited backup power.
2. Due to their quiet operation, low weight, resistance to temperature extremes and virtually vibration-free operation, fuel cells can be installed outdoors, in industrial premises/containers or on rooftops.
3. On-site preparations for using the system are quick and economical, and the cost of operation is low.
4. The fuel is biodegradable and represents an environmentally friendly solution for the urban environment.

Application of fuel cells/cells in security systems

The most carefully designed building security and communication systems are only as reliable as the power that powers them. While most systems include some type of back-up uninterruptible power system for short-term power losses, they do not provide for the longer power outages that can occur after natural disasters or terrorist attacks. This could be a critical issue for many corporate and government agencies.

Vital systems such as CCTV monitoring and access control systems (ID card readers, door closing devices, biometric identification technology, etc.), automatic fire alarm and fire extinguishing systems, elevator control systems and telecommunication networks, are at risk in the absence of a reliable alternative source of continuous power supply.

Diesel generators are noisy, difficult to locate, and are well known for their reliability and maintenance. In contrast, a fuel cell back-up installation is quiet, reliable, has zero or very low emissions, and is easy to install on a rooftop or outside a building. It does not discharge or lose power in standby mode. It ensures the continued operation of critical systems, even after the institution ceases operations and the building is abandoned by people.

Innovative fuel cell installations protect expensive investments in critical applications. They provide environmentally friendly, reliable backup power with extended duration (up to many days) for use in the power range from 250 W to 15 kW, combined with numerous unsurpassed features and, especially, a high level of energy saving.

Fuel cell power backup units offer numerous advantages for mission critical applications such as security and building management systems over traditional battery or diesel generators. Liquid fuel technology solves the problem of hydrogen storage and provides virtually unlimited backup power.

Application of fuel cells/cells in domestic heating and power generation

Solid oxide fuel cells (SOFCs) are used to build reliable, energy-efficient and emission-free thermal power plants to generate electricity and heat from widely available natural gas and renewable fuel sources. These innovative units are used in a wide variety of markets, from domestic power generation to power supply to remote areas, as well as auxiliary power sources.

These energy-saving units produce heat for space heating and hot water, as well as electricity that can be used in the home and fed back into the power grid. Distributed power generation sources can include photovoltaic (solar) cells and micro wind turbines. These technologies are visible and widely known, but their operation is dependent on weather conditions and they cannot consistently generate electricity all year round. In terms of power, thermal power plants can vary from less than 1 kW to 6 MW and more.

Application of fuel cells/cells in distribution networks

Small thermal power plants are designed to operate in a distributed power generation network consisting of a large number of small generator sets instead of one centralized power plant.

The figure below shows the loss in efficiency of electricity generation when it is generated by CHP and transmitted to homes through the traditional transmission networks currently in use. Efficiency losses in district generation include losses from the power plant, low and high voltage transmission, and distribution losses.

The figure shows the results of the integration of small thermal power plants: electricity is generated with a generation efficiency of up to 60% at the point of use. In addition, the household can use the heat generated by the fuel cells for water and space heating, which increases the overall efficiency of fuel energy processing and improves energy savings.

Using Fuel Cells to Protect the Environment - Utilization of Associated Petroleum Gas

One of the most important tasks in the oil industry is the utilization of associated petroleum gas. The existing methods of utilization of associated petroleum gas have a lot of disadvantages, the main one being that they are not economically viable. Associated petroleum gas is flared, which causes great harm to the environment and human health.

Innovative fuel cell heat and power plants using associated petroleum gas as a fuel open the way to a radical and cost-effective solution to the problems of associated petroleum gas utilization.

1. One of the main advantages of fuel cell installations is that they can operate reliably and sustainably on variable composition associated petroleum gas. Due to the flameless chemical reaction underlying the operation of a fuel cell, a reduction in the percentage of, for example, methane only causes a corresponding reduction in power output.
2. Flexibility in relation to the electrical load of consumers, differential, load surge.
3. For the installation and connection of thermal power plants on fuel cells, their implementation does not require capital expenditures, because The units are easily mounted on unprepared sites near fields, are easy to operate, reliable and efficient.
4. High automation and modern remote control do not require the constant presence of personnel at the plant.
5. Simplicity and technical perfection of the design: the absence of moving parts, friction, lubrication systems provides significant economic benefits from the operation of fuel cell installations.
6. Water consumption: none at ambient temperatures up to +30 °C and negligible at higher temperatures.
7. Water outlet: none.
8. In addition, fuel cell thermal power plants do not make noise, do not vibrate,

Fuel cells are a way to electrochemically convert hydrogen fuel energy into electricity, and the only by-product of this process is water.

The hydrogen fuel currently used in fuel cells is usually derived from steam reforming of methane (i.e., converting hydrocarbons with steam and heat to methane), although the approach could be greener, such as electrolysis of water using solar energy.

The main components of a fuel cell are:

• an anode in which hydrogen is oxidized;
• cathode, where oxygen is reduced;
• a polymer electrolyte membrane through which protons or hydroxide ions are transported (depending on the medium) - it does not allow hydrogen and oxygen to pass through;
• flow fields of oxygen and hydrogen, which are responsible for the delivery of these gases to the electrode.

In order to power, for example, a car, several fuel cells are assembled into a battery, and the amount of energy supplied by this battery depends on the total area of ​​the electrodes and the number of cells in it. Energy in a fuel cell is generated as follows: hydrogen is oxidized at the anode, and the electrons from it are sent to the cathode, where oxygen is reduced. The electrons obtained from the oxidation of hydrogen at the anode have a higher chemical potential than the electrons that reduce oxygen at the cathode. This difference between the chemical potentials of the electrons makes it possible to extract energy from fuel cells.

History of creation

The history of fuel cells goes back to the 1930s, when the first hydrogen fuel cell was designed by William R. Grove. This cell used sulfuric acid as the electrolyte. Grove tried to deposit copper from an aqueous solution of copper sulfate onto an iron surface. He noticed that under the action of an electron current, water decomposes into hydrogen and oxygen. After this discovery, Grove and Christian Schoenbein, a chemist at the University of Basel (Switzerland), who worked in parallel with him, simultaneously demonstrated in 1839 the possibility of generating energy in a hydrogen-oxygen fuel cell using an acidic electrolyte. These early attempts, although quite primitive in nature, attracted the attention of several of their contemporaries, including Michael Faraday.

Research into fuel cells continued, and in the 1930s F.T. Bacon introduced a new component to an alkaline fuel cell (one of the types of fuel cells) - an ion-exchange membrane to facilitate the transport of hydroxide ions.

One of the most famous historical examples of the use of alkaline fuel cells is their use as the main source of energy during space flights in the Apollo program.

They were chosen by NASA for their durability and technical stability. They used a hydroxide-conducting membrane that was superior in efficiency to its proton-exchange sister.

For almost two centuries since the creation of the first fuel cell prototype, a lot of work has been done to improve them. In general, the final energy obtained from a fuel cell depends on the kinetics of the redox reaction, the internal resistance of the cell, and the mass transfer of the reacting gases and ions to the catalytically active components. Over the years, many improvements have been made to the original idea, such as:

1) replacement of platinum wires with electrodes based on carbon with platinum nanoparticles; 2) the invention of membranes of high conductivity and selectivity, such as Nafion, to facilitate ion transport; 3) combining the catalytic layer, for example, platinum nanoparticles, distributed over a carbon base, with ion-exchange membranes, resulting in a membrane-electrode unit with a minimum internal resistance; 4) use and optimization of flow fields to deliver hydrogen and oxygen to the catalytic surface, instead of directly diluting them in solution.

These and other improvements eventually resulted in a technology that was efficient enough to be used in vehicles such as the Toyota Mirai.

Fuel cells with hydroxide exchange membranes

The University of Delaware is conducting research on the development of fuel cells with hydroxide exchange membranes - HEMFCs (hydroxide exchange membrane fuel cells). Fuel cells with hydroxide exchange membranes instead of proton exchange membranes - PEMFCs (proton exchange membrane fuel cells) - face less one of the big problems of PEMFCs - the problem of catalyst stability, since many more base metal catalysts are stable in an alkaline environment than in an acidic one. The stability of catalysts in alkaline solutions is higher due to the fact that the dissolution of metals releases more energy at low pH than at high pH. Most of the work in this laboratory is also devoted to the development of new anodic and cathodic catalysts for hydrogen oxidation and oxygen reduction reactions to accelerate them even more efficiently. In addition, the laboratory is developing new hydroxide exchange membranes, as the conductivity and durability of such membranes have yet to be improved in order to compete with proton exchange membranes.

Search for new catalysts

The reason for the overvoltage losses in the oxygen reduction reaction is explained by the linear scale relationships between the intermediate products of this reaction. In the traditional four-electron mechanism of this reaction, oxygen is reduced sequentially, creating intermediate products - OOH*, O* and OH*, to eventually form water (H2O) on the catalytic surface. Since the adsorption energies of intermediate products on an individual catalyst are highly correlated with each other, no catalyst has yet been found that, at least in theory, would not have overvoltage losses. Although the rate of this reaction is low, changing from an acidic medium to an alkaline medium, such as in HEMFC, does not affect it much. However, the rate of the hydrogen oxidation reaction is almost halved, and this fact motivates research aimed at finding the cause of this decrease and the discovery of new catalysts.

Advantages of fuel cells

In contrast to hydrocarbon fuels, fuel cells are more, if not perfectly, environmentally friendly and do not produce greenhouse gases as a result of their activities. Moreover, their fuel (hydrogen) is in principle renewable, since it can be obtained by hydrolysis of water. Thus, hydrogen fuel cells in the future promise to become a full part of the energy production process, in which solar and wind energy is used to produce hydrogen fuel, which is then used in a fuel cell to produce water. Thus, the cycle is closed and no carbon footprint is left.

Unlike rechargeable batteries, fuel cells have the advantage that they do not need to be recharged - they can immediately start supplying energy as soon as it is needed. That is, if they are applied, for example, in the field of vehicles, then there will be almost no changes on the part of the consumer. Unlike solar energy and wind energy, fuel cells can produce energy continuously and are much less dependent on external conditions. In turn, geothermal energy is only available in certain geographic areas, while fuel cells again do not have this problem.

Hydrogen fuel cells are one of the most promising energy sources due to their portability and flexibility in terms of scale.

Complexity of hydrogen storage

In addition to the problems with the shortcomings of the current membranes and catalysts, other technical difficulties for fuel cells are associated with the storage and transport of hydrogen fuel. Hydrogen has a very low specific energy per unit volume (the amount of energy per unit volume at a given temperature and pressure) and therefore must be stored at very high pressure to be used in vehicles. Otherwise, the size of the container for storing the required amount of fuel will be impossibly large. Because of these hydrogen storage limitations, attempts have been made to find ways to produce hydrogen from something other than its gaseous form, such as in metal hydride fuel cells. However, current consumer fuel cell applications, such as the Toyota Mirai, use supercritical hydrogen (hydrogen that is at temperatures above 33 K and pressures above 13.3 atmospheres, that is, above critical values), and this is now the most convenient option.

Perspectives of the region

Due to the existing technical difficulties and problems of obtaining hydrogen from water using solar energy, in the near future, research is likely to focus mainly on finding alternative sources of hydrogen. One popular idea is to use ammonia (hydrogen nitride) directly in the fuel cell instead of hydrogen, or to make hydrogen from ammonia. The reason for this is that ammonia is less demanding in terms of pressure, which makes it more convenient to store and move. In addition, ammonia is attractive as a source of hydrogen because it does not contain carbon. This solves the problem of catalyst poisoning due to some CO in the hydrogen produced from methane.

In the future, fuel cells may find wide applications in vehicle technology and distributed energy generation, such as in residential areas. Despite the fact that at the moment the use of fuel cells as the main source of energy requires a lot of money, if cheaper and more efficient catalysts, stable membranes with high conductivity and alternative sources of hydrogen are found, hydrogen fuel cells can become highly economically attractive.

Chemical processes in a fuel cell

Fuel cells use an electrochemical process to combine hydrogen with oxygen from the air. Like batteries, fuel cells use electrodes (solid electrical conductors) in an electrolyte (an electrically conductive medium). When hydrogen molecules come into contact with the negative electrode (anode), the latter are separated into protons and electrons. The protons pass through the proton exchange membrane (POM) to the positive electrode (cathode) of the fuel cell, producing electricity. There is a chemical combination of hydrogen and oxygen molecules with the formation of water, as a by-product of this reaction. The only type of emissions from a fuel cell is water vapour.
The electricity produced by fuel cells can be used in the vehicle's electrical powertrain (consisting of an electrical power converter and an AC induction motor) to provide mechanical energy to propel the vehicle. The job of the power converter is to convert the direct current produced by the fuel cells into alternating current, which is used by the vehicle's traction motor.

Schematic diagram of a fuel cell with a proton-exchange membrane:
1 - anode;
2 - proton-exchange membrane (REM);
3 - catalyst (red);
4 - cathode

The Proton Exchange Membrane Fuel Cell (PEMFC) uses one of the simplest reactions of any fuel cell.

Separate fuel cell

Consider how a fuel cell works. The anode, the negative pole of the fuel cell, conducts the electrons, which are freed from hydrogen molecules so that they can be used in an external electrical circuit (circuit). To do this, channels are engraved in it, distributing hydrogen evenly over the entire surface of the catalyst. The cathode (positive pole of the fuel cell) has engraved channels that distribute oxygen over the surface of the catalyst. It also conducts electrons back from the outer circuit (circuit) to the catalyst, where they can combine with hydrogen ions and oxygen to form water. The electrolyte is a proton-exchange membrane. This is a special material, similar to ordinary plastic, but with the ability to pass positively charged ions and block the passage of electrons.
A catalyst is a special material that facilitates the reaction between oxygen and hydrogen. The catalyst is usually made from platinum powder deposited in a very thin layer on carbon paper or cloth. The catalyst must be rough and porous so that its surface can come into contact with hydrogen and oxygen as much as possible. The platinum coated side of the catalyst is in front of the proton exchange membrane (POM).
Hydrogen gas (H 2 ) is supplied to the fuel cell under pressure from the anode side. When the H2 molecule comes into contact with the platinum on the catalyst, it splits into two parts, two ions (H+) and two electrons (e–). The electrons are conducted through the anode, where they pass through an external circuit (circuit), doing useful work (for example, driving an electric motor) and returning from the cathode side of the fuel cell.
Meanwhile, from the cathode side of the fuel cell, oxygen gas (O 2 ) is forced through the catalyst where it forms two oxygen atoms. Each of these atoms has a strong negative charge that attracts two H+ ions across the membrane, where they combine with an oxygen atom and two electrons from the outer loop (chain) to form a water molecule (H 2 O).
This reaction in a single fuel cell produces a power of approximately 0.7 watts. In order to raise the power to the required level, it is necessary to combine many individual fuel cells to form a fuel cell stack.
POM fuel cells operate at a relatively low temperature (about 80°C), which means that they can be quickly heated to operating temperature and do not require expensive cooling systems. Continuous improvement in the technologies and materials used in these cells has brought their power closer to a level where a battery of such fuel cells, occupying a small part of the trunk of a car, can provide the energy needed to drive a car.
Over the past years, most of the world's leading car manufacturers have invested heavily in the development of car designs using fuel cells. Many have already demonstrated fuel cell vehicles with satisfactory power and dynamic characteristics, although they were quite expensive.
Improving the design of such cars is very intensive.

Fuel cell vehicle, uses a power plant located under the floor of the vehicle

The NECAR V vehicle is based on the Mercedes-Benz A-class vehicle, with the entire power plant, together with the fuel cells, located under the floor of the vehicle. Such a constructive solution makes it possible to accommodate four passengers and luggage in the car. Here, not hydrogen, but methanol is used as fuel for the car. Methanol with the help of a reformer (a device that converts methanol into hydrogen) is converted into hydrogen, which is necessary to power the fuel cell. The use of a reformer on board a car makes it possible to use almost any hydrocarbon as a fuel, which makes it possible to refuel a fuel cell car using the existing filling station network. Theoretically, fuel cells produce nothing but electricity and water. Converting the fuel (gasoline or methanol) to the hydrogen required for the fuel cell somewhat reduces the environmental appeal of such a vehicle.
Honda, which has been in the fuel cell business since 1989, produced a small batch of Honda FCX-V4 vehicles in 2003 with proton exchange fuel cells. membrane type Ballard firm. These fuel cells generate 78 kW electrical power, and traction motors with a power of 60 kW and a torque of 272 N m are used to drive the drive wheels. A fuel cell car, compared to a traditional car, has a mass of about 40% less, which provides it with excellent dynamics, and a supply of compressed hydrogen gives the possibility of running up to 355 km.

The Honda FCX uses fuel cell power to propel itself.
The Honda FCX is the world's first fuel cell vehicle to receive government certification in the United States. The car is ZEV certified - Zero Emission Vehicle (zero pollution vehicle). Honda is not going to sell these cars yet, but leases about 30 cars per unit. California and Tokyo, where hydrogen fueling infrastructure already exists.

General Motors' Hy Wire concept car has a fuel cell power plant

Large research on the development and creation of fuel cell vehicles is being conducted by General Motors.

Hy Wire Vehicle Chassis

The GM Hy Wire concept car has received 26 patents. The basis of the car is a functional platform with a thickness of 150 mm. Inside the platform are hydrogen cylinders, a fuel cell power plant and vehicle control systems using the latest technology electronic control by wire. The chassis of the Hy Wire car is a thin platform that contains all the main structural elements of the car: hydrogen cylinders, fuel cells, batteries, electric motors and control systems. This approach to design makes it possible to change car bodies during operation. The company also tests experimental Opel fuel cell vehicles and designs a fuel cell production plant.

Design of a "safe" fuel tank for liquefied hydrogen:
1 - filling device;
2 - outer tank;
3 - supports;
4 - level sensor;
5 - internal tank;
6 - filling line;
7 - isolation and vacuum;
8 - heater;
9 - mounting box

The problem of using hydrogen as a fuel for cars is paid much attention to by BMW. Together with Magna Steyer, known for its work on the use of liquefied hydrogen in space research, BMW has developed a liquefied hydrogen fuel tank that can be used in cars.

Tests have confirmed the safety of using a fuel tank with liquid hydrogen

The company conducted a series of tests on the safety of the structure according to standard methods and confirmed its reliability.
In 2002, at the Frankfurt Motor Show (Germany), the Mini Cooper Hydrogen was shown, which uses liquefied hydrogen as fuel. Fuel tank This car takes up the same space as a conventional gas tank. Hydrogen in this car is not used for fuel cells, but as fuel for internal combustion engines.

The world's first mass-produced car with a fuel cell instead of a battery

In 2003, BMW announced the launch of the first mass-produced fuel cell vehicle, the BMW 750 hL. A fuel cell battery is used instead of a traditional battery. This car has a 12-cylinder internal combustion engine running on hydrogen, and the fuel cell serves as an alternative to a conventional battery, allowing the air conditioner and other consumers to work when the car is parked for a long time with the engine off.

Hydrogen refueling is performed by a robot, the driver is not involved in this process

The same company BMW has also developed robotic fuel dispensers that provide fast and safe refueling of cars with liquefied hydrogen.
The emergence in recent years of a large number of developments aimed at creating cars using alternative fuels and alternative propulsion systems indicates that internal combustion engines, which dominated cars for the past century, will eventually give way to cleaner, more efficient and silent designs. Their widespread use is currently being held back not by technical, but rather by economic and social problems. For their widespread use, it is necessary to create a certain infrastructure for the development of the production of alternative fuels, the creation and distribution of new gas stations and to overcome a number of psychological barriers. The use of hydrogen as a vehicle fuel will require storage, delivery and distribution issues to be addressed, with serious safety measures in place.
Theoretically, hydrogen is available in unlimited quantities, but its production is very energy intensive. In addition, in order to convert cars to work on hydrogen fuel, two big changes in the power system must be made: first, transferring its operation from gasoline to methanol, and then, for some time, to hydrogen. It will be some time before this issue is resolved.

Description:

This article discusses in more detail their structure, classification, advantages and disadvantages, scope, efficiency, history of creation and modern prospects for use.

Using fuel cells to power buildings

Part 1

This article discusses in more detail the principle of operation of fuel cells, their design, classification, advantages and disadvantages, scope, efficiency, history of creation and modern prospects for use. In the second part of the article, which will be published in the next issue of the ABOK magazine, provides examples of facilities where various types of fuel cells were used as sources of heat and electricity (or only electricity).

Introduction

Fuel cells are a very efficient, reliable, durable and environmentally friendly way to generate energy.

Initially used only in the space industry, fuel cells are now increasingly being used in a variety of areas - such as stationary power plants, heat and power supply of buildings, vehicle engines, power supplies for laptops and mobile phones. Some of these devices are laboratory prototypes, some are undergoing pre-series testing or are used for demonstration purposes, but many models are mass-produced and used in commercial projects.

A fuel cell (electrochemical generator) is a device that converts the chemical energy of fuel (hydrogen) into electrical energy in the process of an electrochemical reaction directly, unlike traditional technologies that use the combustion of solid, liquid and gaseous fuels. Direct electrochemical conversion of fuel is very efficient and attractive from an environmental point of view, since the minimum amount of pollutants is released during operation, and there are no strong noises and vibrations.

From a practical point of view, a fuel cell resembles a conventional galvanic battery. The difference lies in the fact that initially the battery is charged, i.e. filled with “fuel”. During operation, "fuel" is consumed and the battery is discharged. Unlike a battery, a fuel cell uses fuel supplied from an external source to generate electrical energy (Fig. 1).

For the production of electrical energy, not only pure hydrogen can be used, but also other hydrogen-containing raw materials, such as natural gas, ammonia, methanol or gasoline. Ordinary air is used as a source of oxygen, which is also necessary for the reaction.

When pure hydrogen is used as a fuel, the reaction products, in addition to electrical energy, are heat and water (or water vapor), i.e. no gases are emitted into the atmosphere that cause air pollution or cause a greenhouse effect. If a hydrogen-containing feedstock, such as natural gas, is used as a fuel, other gases, such as oxides of carbon and nitrogen, will be a by-product of the reaction, but its amount is much lower than when burning the same amount of natural gas.

The process of chemical conversion of fuel in order to produce hydrogen is called reforming, and the corresponding device is called a reformer.

Advantages and disadvantages of fuel cells

Fuel cells are more energy efficient than internal combustion engines because there is no thermodynamic limitation on energy efficiency for fuel cells. The efficiency of fuel cells is 50%, while the efficiency of internal combustion engines is 12-15%, and the efficiency of steam turbine power plants does not exceed 40%. By using heat and water, the efficiency of fuel cells is further increased.

In contrast to, for example, internal combustion engines, the efficiency of fuel cells remains very high even when they are not operating at full power. In addition, the power of fuel cells can be increased by simply adding separate blocks, while the efficiency does not change, i.e. large installations are as efficient as small ones. These circumstances allow a very flexible selection of the composition of equipment in accordance with the wishes of the customer and ultimately lead to a reduction in equipment costs.

An important advantage of fuel cells is their environmental friendliness. Air emissions from fuel cells are so low that in some parts of the United States they do not require special permits from government air quality agencies.

Fuel cells can be placed directly in the building, thus reducing energy transmission losses, and the heat generated as a result of the reaction can be used to supply heat or hot water to the building. Autonomous sources of heat and power supply can be very beneficial in remote areas and in regions that are characterized by a shortage of electricity and its high cost, but at the same time there are reserves of hydrogen-containing raw materials (oil, natural gas).

The advantages of fuel cells are also the availability of fuel, reliability (there are no moving parts in the fuel cell), durability and ease of operation.

One of the main shortcomings of fuel cells today is their relatively high cost, but this shortcoming can be overcome soon - more and more companies produce commercial samples of fuel cells, they are constantly being improved, and their cost is decreasing.

The most efficient use of pure hydrogen as a fuel, however, this will require the creation of a special infrastructure for its production and transportation. Currently, all commercial designs use natural gas and similar fuels. Motor vehicles can use ordinary gasoline, which will allow maintaining the existing developed network of gas stations. However, the use of such fuel leads to harmful emissions into the atmosphere (albeit very low) and complicates (and therefore increases the cost of) the fuel cell. In the future, the possibility of using environmentally friendly renewable energy sources (for example, solar energy or wind energy) is being considered to decompose water into hydrogen and oxygen by electrolysis, and then convert the resulting fuel in a fuel cell. Such combined plants operating in a closed cycle can be a completely environmentally friendly, reliable, durable and efficient source of energy.

Another feature of fuel cells is that they are most efficient when using both electrical and thermal energy at the same time. However, the possibility of using thermal energy is not available at every facility. In the case of using fuel cells only for generating electrical energy, their efficiency decreases, although it exceeds the efficiency of “traditional” installations.

History and modern uses of fuel cells

The principle of operation of fuel cells was discovered in 1839. The English scientist William Grove (1811-1896) discovered that the process of electrolysis - the decomposition of water into hydrogen and oxygen by means of an electric current - is reversible, i.e. hydrogen and oxygen can be combined into water molecules without combustion, but with the release of heat and electric current. Grove called the device in which such a reaction was carried out a "gas battery", which was the first fuel cell.

The active development of fuel cell technologies began after the Second World War, and it is associated with the aerospace industry. At that time, searches were conducted for an efficient and reliable, but at the same time quite compact source of energy. In the 1960s, NASA specialists (National Aeronautics and Space Administration, NASA) chose fuel cells as a power source for spacecraft of the Apollo (manned flights to the Moon), Apollo-Soyuz, Gemini and Skylab programs. . The Apollo used three 1.5 kW units (2.2 kW peak power) using cryogenic hydrogen and oxygen to produce electricity, heat and water. The mass of each installation was 113 kg. These three cells worked in parallel, but the energy generated by one unit was enough for a safe return. During 18 flights, the fuel cells have accumulated a total of 10,000 hours without any failures. Currently, fuel cells are used in the space shuttle "Space Shuttle", which uses three units with a power of 12 W, which generate all the electrical energy on board the spacecraft (Fig. 2). Water obtained as a result of an electrochemical reaction is used as drinking water, as well as for cooling equipment.

In our country, work was also underway to create fuel cells for use in astronautics. For example, fuel cells were used to power the Soviet Buran space shuttle.

Development of methods for the commercial use of fuel cells began in the mid-1960s. These developments were partially funded by government organizations.

Currently, the development of technologies for the use of fuel cells goes in several directions. This is the creation of stationary power plants on fuel cells (for both centralized and decentralized energy supply), power plants of vehicles (samples of cars and buses on fuel cells have been created, including in our country) (Fig. 3), and also power supplies for various mobile devices (laptops, mobile phones, etc.) (Fig. 4).

Examples of the use of fuel cells in various fields are given in Table. one.

One of the first commercial models of fuel cells designed for autonomous heat and power supply of buildings was the PC25 Model A manufactured by ONSI Corporation (now United Technologies, Inc.). This fuel cell with a nominal power of 200 kW belongs to the type of cells with an electrolyte based on phosphoric acid (Phosphoric Acid Fuel Cells, PAFC). The number "25" in the name of the model means the serial number of the design. Most of the previous models were experimental or test pieces, such as the 12.5 kW "PC11" model that appeared in the 1970s. The new models increased the power taken from a single fuel cell, and also reduced the cost per kilowatt of energy produced. Currently, one of the most efficient commercial models is the PC25 Model C fuel cell. Like model "A", this is a fully automatic fuel cell of the PAFC type with a power of 200 kW, designed to be installed directly on the serviced object as an independent source of heat and electricity. Such a fuel cell can be installed outside the building. Outwardly, it is a parallelepiped 5.5 m long, 3 m wide and 3 m high, weighing 18,140 kg. The difference from previous models is an improved reformer and a higher current density.

In some types of fuel cells, the chemical process can be reversed: by applying a potential difference to the electrodes, water can be decomposed into hydrogen and oxygen, which are collected on porous electrodes. When a load is connected, such a regenerative fuel cell will begin to generate electrical energy.

A promising direction for the use of fuel cells is their use in conjunction with renewable energy sources, such as photovoltaic panels or wind turbines. This technology allows you to completely avoid air pollution. A similar system is planned to be created, for example, at the Adam Joseph Lewis Training Center in Oberlin (see ABOK, 2002, No. 5, p. 10). Currently, solar panels are used as one of the energy sources in this building. Together with NASA specialists, a project was developed to use photovoltaic panels to produce hydrogen and oxygen from water by electrolysis. The hydrogen is then used in fuel cells to generate electrical energy and hot water. This will allow the building to maintain the performance of all systems during cloudy days and at night.

The principle of operation of fuel cells

Let us consider the principle of operation of a fuel cell using the simplest element with a proton exchange membrane (Proton Exchange Membrane, PEM) as an example. Such an element consists of a polymer membrane placed between the anode (positive electrode) and the cathode (negative electrode) together with the anode and cathode catalysts. A polymer membrane is used as the electrolyte. The diagram of the PEM element is shown in fig. 5.

A proton exchange membrane (PEM) is a thin (approximately 2-7 sheets of plain paper thick) solid organic compound. This membrane functions as an electrolyte: it separates matter into positively and negatively charged ions in the presence of water.

An oxidative process occurs at the anode, and a reduction process occurs at the cathode. The anode and cathode in the PEM cell are made of a porous material, which is a mixture of particles of carbon and platinum. Platinum acts as a catalyst that promotes the dissociation reaction. The anode and cathode are made porous for free passage of hydrogen and oxygen through them, respectively.

The anode and cathode are placed between two metal plates, which supply hydrogen and oxygen to the anode and cathode, and remove heat and water, as well as electrical energy.

Hydrogen molecules pass through the channels in the plate to the anode, where the molecules decompose into individual atoms (Fig. 6).

Then, as a result of chemisorption in the presence of a catalyst, hydrogen atoms, each donating one electron e - , are converted into positively charged hydrogen ions H +, i.e. protons (Fig. 7).

Positively charged hydrogen ions (protons) diffuse through the membrane to the cathode, and the electron flow is directed to the cathode through an external electrical circuit to which the load (consumer of electrical energy) is connected (Fig. 8).

Oxygen supplied to the cathode, in the presence of a catalyst, enters into a chemical reaction with hydrogen ions (protons) from the proton exchange membrane and electrons from the external electrical circuit (Fig. 9). As a result of a chemical reaction, water is formed.

The chemical reaction in a fuel cell of other types (for example, with an acidic electrolyte, which is a solution of phosphoric acid H 3 PO 4) is absolutely identical to the chemical reaction in a fuel cell with a proton exchange membrane.

In any fuel cell, part of the energy of a chemical reaction is released as heat.

The flow of electrons in an external circuit is a direct current that is used to do work. Opening the external circuit or stopping the movement of hydrogen ions stops the chemical reaction.

The amount of electrical energy produced by a fuel cell depends on the type of fuel cell, geometric dimensions, temperature, gas pressure. A single fuel cell provides an EMF of less than 1.16 V. It is possible to increase the size of the fuel cells, but in practice several cells are used, connected in batteries (Fig. 10).

Fuel cell device

Let's consider the fuel cell device on the example of the PC25 Model C model. The scheme of the fuel cell is shown in fig. eleven.

The fuel cell "PC25 Model C" consists of three main parts: the fuel processor, the actual power generation section and the voltage converter.

The main part of the fuel cell - the power generation section - is a stack composed of 256 individual fuel cells. The composition of the fuel cell electrodes includes a platinum catalyst. Through these cells, a direct electric current of 1,400 amperes is generated at a voltage of 155 volts. The dimensions of the battery are approximately 2.9 m in length and 0.9 m in width and height.

Since the electrochemical process takes place at a temperature of 177 ° C, it is necessary to heat the battery at the time of start-up and remove heat from it during operation. To do this, the fuel cell includes a separate water circuit, and the battery is equipped with special cooling plates.

The fuel processor allows you to convert natural gas into hydrogen, which is necessary for an electrochemical reaction. This process is called reforming. The main element of the fuel processor is the reformer. In the reformer, natural gas (or other hydrogen-containing fuel) reacts with steam at high temperature (900 °C) and high pressure in the presence of a nickel catalyst. The following chemical reactions take place:

CH 4 (methane) + H 2 O 3H 2 + CO

(reaction endothermic, with heat absorption);

CO + H 2 O H 2 + CO 2

(the reaction is exothermic, with the release of heat).

The overall reaction is expressed by the equation:

CH 4 (methane) + 2H 2 O 4H 2 + CO 2

(reaction endothermic, with heat absorption).

To provide the high temperature required for natural gas conversion, a portion of the spent fuel from the fuel cell stack is directed to a burner that maintains the reformer at the required temperature.

The steam required for reforming is generated from the condensate formed during the operation of the fuel cell. In this case, the heat removed from the fuel cell stack is used (Fig. 12).

The fuel cell stack generates an intermittent direct current, which is characterized by low voltage and high current. A voltage converter is used to convert it to industrial standard AC. In addition, the voltage converter unit includes various control devices and safety interlock circuits that allow the fuel cell to be turned off in the event of various failures.

In such a fuel cell, approximately 40% of the energy in the fuel can be converted into electrical energy. Approximately the same amount, about 40% of the fuel energy, can be converted into, which is then used as a heat source for heating, hot water supply and similar purposes. Thus, the total efficiency of such a plant can reach 80%.

An important advantage of such a source of heat and electricity is the possibility of its automatic operation. For maintenance, the owners of the facility on which the fuel cell is installed do not need to maintain specially trained personnel - periodic maintenance can be carried out by employees of the operating organization.

Fuel cell types

Currently, several types of fuel cells are known, which differ in the composition of the electrolyte used. The following four types are most widespread (Table 2):

1. Fuel cells with proton exchange membrane (Proton Exchange Membrane Fuel Cells, PEMFC).

2. Fuel cells based on orthophosphoric (phosphoric) acid (Phosphoric Acid Fuel Cells, PAFC).

3. Fuel cells based on molten carbonate (Molten Carbonate Fuel Cells, MCFC).

4. Solid oxide fuel cells (Solid Oxide Fuel Cells, SOFC). Currently, the largest fleet of fuel cells is built on the basis of PAFC technology.

One of the key characteristics of different types of fuel cells is the operating temperature. In many ways, it is the temperature that determines the scope of fuel cells. For example, high temperatures are critical for laptops, so proton exchange membrane fuel cells with low operating temperatures are being developed for this market segment.

For autonomous power supply of buildings, fuel cells of high installed capacity are required, and at the same time, it is possible to use thermal energy, therefore, other types of fuel cells can be used for these purposes.

Proton Exchange Membrane Fuel Cells (PEMFC)

These fuel cells operate at relatively low operating temperatures (60-160°C). They are characterized by high power density, allow you to quickly adjust the output power, and can be quickly turned on. The disadvantage of this type of elements is the high requirements for fuel quality, since contaminated fuel can damage the membrane. The nominal power of fuel cells of this type is 1-100 kW.

Proton exchange membrane fuel cells were originally developed by the General Electric Corporation in the 1960s for NASA. This type of fuel cell uses a solid state polymer electrolyte called a Proton Exchange Membrane (PEM). Protons can move through the proton exchange membrane, but electrons cannot pass through it, resulting in a potential difference between the cathode and anode. Due to their simplicity and reliability, such fuel cells were used as a power source on the Gemini manned spacecraft.

This type of fuel cell is used as a power source for a wide range of different devices, including prototypes and prototypes, from mobile phones to buses and stationary power systems. The low operating temperature allows such cells to be used to power various types of complex electronic devices. Less efficient is their use as a source of heat and power supply for public and industrial buildings, where large amounts of thermal energy are required. At the same time, such elements are promising as an autonomous source of power supply for small residential buildings such as cottages built in regions with a hot climate.

Phosphoric Acid Fuel Cells (PAFC)

Tests of fuel cells of this type were already carried out in the early 1970s. Operating temperature range - 150-200 °C. The main area of ​​application is autonomous sources of heat and power supply of medium power (about 200 kW).

The electrolyte used in these fuel cells is a solution of phosphoric acid. The electrodes are made of paper coated with carbon, in which a platinum catalyst is dispersed.

The electrical efficiency of PAFC fuel cells is 37-42%. However, since these fuel cells operate at a sufficiently high temperature, it is possible to use the steam generated as a result of operation. In this case, the overall efficiency can reach 80%.

To generate energy, the hydrogen-containing feedstock must be converted to pure hydrogen through a reforming process. For example, if gasoline is used as a fuel, then sulfur compounds must be removed, since sulfur can damage the platinum catalyst.

PAFC fuel cells were the first commercial fuel cells to be economically justified. The most common model was the 200 kW PC25 fuel cell manufactured by ONSI Corporation (now United Technologies, Inc.) (Fig. 13). For example, these elements are used as a source of heat and electricity in a police station in New York's Central Park or as an additional source of energy for the Conde Nast Building & Four Times Square. The most big rig of this type is being tested as an 11 MW power plant located in Japan.

Fuel cells based on phosphoric acid are also used as an energy source in vehicles. For example, in 1994, H-Power Corp., Georgetown University, and the US Department of Energy equipped a bus with a 50 kW power plant.

Molten Carbonate Fuel Cells (MCFC)

Fuel cells of this type operate at very high temperatures - 600-700 °C. These operating temperatures allow the fuel to be used directly in the cell itself, without the need for a separate reformer. This process is called "internal reforming". It allows to significantly simplify the design of the fuel cell.

Fuel cells based on molten carbonate require a significant start-up time and do not allow to quickly adjust the output power, so their main area of ​​application is large stationary sources of heat and electricity. However, they are distinguished by high fuel conversion efficiency - 60% electrical efficiency and up to 85% overall efficiency.

In this type of fuel cell, the electrolyte consists of potassium carbonate and lithium carbonate salts heated to about 650 °C. Under these conditions, the salts are in a molten state, forming an electrolyte. At the anode, hydrogen interacts with CO 3 ions, forming water, carbon dioxide and releasing electrons that are sent to the external circuit, and at the cathode, oxygen interacts with carbon dioxide and electrons from the external circuit, again forming CO 3 ions.

Laboratory samples of fuel cells of this type were created in the late 1950s by the Dutch scientists G. H. J. Broers and J. A. A. Ketelaar. In the 1960s, engineer Francis T. Bacon, a descendant of a famous 17th-century English writer and scientist, worked with these elements, which is why MCFC fuel cells are sometimes referred to as Bacon elements. NASA's Apollo, Apollo-Soyuz, and Scylab programs used just such fuel cells as a power source (Fig. 14). In the same years, the US military department tested several samples of MCFC fuel cells manufactured by Texas Instruments, in which army grades of gasoline were used as fuel. In the mid-1970s, the US Department of Energy began research to develop a stationary molten carbonate fuel cell suitable for practical application. In the 1990s, a number of commercial units rated up to 250 kW were put into operation, such as at the US Naval Air Station Miramar in California. In 1996, FuelCell Energy, Inc. commissioned a 2 MW pre-series plant in Santa Clara, California.

Solid state oxide fuel cells (SOFC)

Solid-state oxide fuel cells are simple in design and operate at very high temperatures - 700-1000 °C. Such high temperatures allow the use of relatively "dirty", unrefined fuel. The same features as in fuel cells based on molten carbonate determine a similar area of ​​application - large stationary sources of heat and electricity.

Solid oxide fuel cells are structurally different from fuel cells based on PAFC and MCFC technologies. The anode, cathode and electrolyte are made of special grades of ceramics. Most often, a mixture of zirconium oxide and calcium oxide is used as the electrolyte, but other oxides can be used. The electrolyte forms a crystal lattice coated on both sides with a porous electrode material. Structurally, such elements are made in the form of tubes or flat boards, which makes it possible to use technologies widely used in the electronics industry in their manufacture. As a result, solid-state oxide fuel cells can operate at very high temperatures, so they can be used to produce both electrical and thermal energy.

At high operating temperatures, oxygen ions are formed at the cathode, which migrate through the crystal lattice to the anode, where they interact with hydrogen ions, forming water and releasing free electrons. In this case, hydrogen is released from natural gas directly in the cell, i.e. there is no need for a separate reformer.

The theoretical foundations for the creation of solid-state oxide fuel cells were laid back in the late 1930s, when Swiss scientists Bauer (Emil Bauer) and Preis (H. Preis) experimented with zirconium, yttrium, cerium, lanthanum and tungsten, using them as electrolytes.

The first prototypes of such fuel cells were created in the late 1950s by a number of American and Dutch companies. Most of these companies soon abandoned further research due to technological difficulties, but one of them, Westinghouse Electric Corp. (now "Siemens Westinghouse Power Corporation"), continued work. The company is currently accepting pre-orders for a commercial model of tubular topology solid oxide fuel cell expected this year (Figure 15). The market segment of such elements is stationary installations for the production of thermal and electric energy with a capacity of 250 kW to 5 MW.

SOFC type fuel cells have shown very high reliability. For example, a Siemens Westinghouse fuel cell prototype has logged 16,600 hours and continues to operate, making it the longest continuous fuel cell life in the world.

The high temperature, high pressure operating mode of SOFC fuel cells allows the creation of hybrid plants, in which fuel cell emissions drive gas turbines used to generate electricity. The first such hybrid plant is in operation in Irvine, California. The rated power of this plant is 220 kW, of which 200 kW from the fuel cell and 20 kW from the microturbine generator.