Problem of absence of constant and uninterrupted power supply is known both to manufacturers and people living in remote areas. Solving them is possible with new ways of storing and generating energy, the most promising is current chemical sources. In these mini-reactors, the energy of chemical transformations directly, without transforming into heat is converted to electricity. Thereby energy losses and fuel consumption are greatly reduced.
Current chemical sources can combine different reactions, and each has its advantages and disadvantages: some quickly "run out of steam", while others can only work under certain conditions, such as ultra-high temperatures, or strictly defined fuels such as pure hydrogen. A group of scientists from the Institute of Solid State Physics, Russian Academy of Sciences (ISSP), under the leadership of Sergei Bredikhin opted for the so-called solid oxide fuel cell (SOFC). Scientists are confident that with the right approach it can replace inefficient generators in the Arctic. Their project was supported within the framework of the Federal Targeted Program "Research and Development for 2014-2020".
Today energy engineers are fighting for each additional percent of efficiency. Worldwide generators are commonly used, operating on the principle of internal combustion of carbon fuel - fuel oil, coal, natural gas (the latter type of fuel is the most environmentally friendly). Losses of energy when they are used is significant: even at a maximum efficiency and when such power plants are optimized the efficiency does not exceed 45%. During the operation they generate nitrogen oxides (NOx), which are in contact with water in the atmosphere to become sufficiently aggressive acid.
In solid oxide fuel cells (SOFC) there are no such "side effects." Such installations have an efficiency over 50% (and that is the output of electric power and by taking into account heat efficiency can reach 85-90%) and they do not expel hazardous compounds in the atmosphere.
"This is a very important technology for the Arctic or Siberia, where the environmental problems are particularly important and the problems with fuel delivery always pend. SOFCs consume less fuel, - said Sergey Bredikhin. - They have to work non-stop, so they are well suited to operate at a polar station, or nothern airport".
Besides a relatively low fuel consumption advantage this installation also can operate without service up to 3-4 years. "Diesel generator, which is most commonly used now, requires oil change after every thousand hours. SOFC plant operates 10-20 thousand hours without maintenance ", - said junior researcher Dmitry Agarkov.
The principle of SOFC operation is quite simple. These are "batteries", which include several layers of solid oxide fuel cells. Each element has an anode and a cathode, to the anode fuel is supplied thereto where as the cathode is supplied with air. It is noteworthy that fuels like pure hydrogen, carbon monoxide and various hydrocarbon compounds are quite suitable for SOFC . As a result of the reactions occurring at the anode and the cathode oxygen and fuel are consumed, and the ion current is generated between the electrodes. When the battery is built in the electrical circuit, current begins to flow.
Unpleasant feature of the SOFC is a need for high temperatures. For example, the sample assembled by ISSP scientists, operates at 850 ° C. To warm up to operating temperature, the generator requires approximately 10 hours, but then it will work for several years.
Solid oxide elements developed at ISSP will produce two kilowatts - depending on the size and quantity of fuel plates and number of these plates in the battery. Small batteries prototypes of 50 watts have already been assembled and tested.
Particular attention should be paid to plates themselves. One plate consists of seven layers, each having its own function. Two layers of the cathode and the anode catalyze the reaction and pass electrons, ceramic layer in between insulates the different media (air and fuel), but allows oxygen ions to pass through. In this case the membrane itself must be strong enough (ceramics of such thickness is very easily damaged), so it is made up of three layers: the center provides the necessary physical properties - high ionic conductivity - whereas additional layers on both sides impart mechanical strength. However, one fuel cell is very thin - no more than 200 microns thick.
But just a fuel cell is not enough to generate electricity. The whole system must be placed in a heat resistant container which is capable to withstand operation for several years at a temperature of 850 ° C. By the way, in the framework of the project to protect the design of the metallic elements ISSP scientists used coatings developed in the course of another project.
"When we started this project, we came across with the fact that in our country there is nothing: no raw material or adhesives or sealants, - Bredikhin said. - We had to do everything. We have done a simulation, practiced on small fuel cells of a tablet size and tried to find put what they should be in composition and configuration, and where they should be located. "
The main partner in this project is the Krylov State Research Center, performing the function of the chief power plant developer, including the development of the necessary design documentation and manufacturing of the hardware in its pilot production facilities. Part of the work is done by other organizations. For example, a ceramic membrane that separates the anode and cathode is produced at the Novosibirsk company NEVZ-Ceramics.
Industrial partner for the project is "Energy without frontiers" foundation. It is supposed it will organize the production of small batches of 2kW generators at Krylov scientific center, but scientists hope to significantly expand the production. According to the developers, the energy obtained from the SOFC generator is competitive even for household use in remote corners of Russia. The cost of 1 kWh is expected to be about 25 rubles, and at the current cost of energy in Yakutia up to 100 rubles per kilowatt-hour such a generator looks very attractive. The market is ready, Sergei Bredikhin is sure, the main thing is to have time to prove oneself.
In Russia, there is another area where the use of SOFC generators looks very promising - a cathodic protection of pipelines. First of all these are gas and oil pipelines, which stretch for hundreds of kilometers in a desert landscape of Siberia. It is known that by applying a voltage to the metal tube it is less susceptible to corrosion. Today cathodic protection stations operate on a thermoelectric generator, for which it is necessary to constantly monitor and effectiveness of which is only 2%. Their only advantage is low price, but if you look in the long term, consider the fuel costs (and they are fueled by the contents of the tube) their cost "merit" seems unconvincing. Using the same stations on SOFC generators it is possible to arrange not only an uninterrupted power supply to the pipeline and but electricity transmission for telemetry shooting as well ... It is said that without science Russia is pipe. It turns out that even this pipe without science and new technologies wont last for long.