SIEMENS

The city of Troitsk near Moscow has an exciting past. It was one of the science centers whose existence the Soviet Union wanted to conceal. The research conducted here in nuclear engineering and materials research was top-notch. The city’s Technological Institute for Superhard and Novel Carbon Materials (TISNCM) has since attained official status. It continues to be a world leader - but today it is part of a worldwide network that also includes Siemens.

One of the most important areas of research in Troitsk is the development of materials that are expected to make power generation and transmission more efficient. “Materials research in nanotechnology is very attractive from a financial point of view,” says Professor Vladimir Blank, head of the TISNCM. “For example, we are incorporating carbon nanoparticles in an aluminum-metal matrix to improve the hardness and strength of alloys while retaining their very good electrical and thermal properties.”

One to one-and-a-half percent by weight of fullerenes, as these new particles are known, is enough to obtain the material properties that Blank is seeking. Fullerenes are molecules that contain 60 carbon atoms (C60) and resemble soccer balls. What makes them so suitable for novel materials is their high mechanical strength at a low weight.

“The new nanostructured aluminum composites are almost three times as hard as normal composites but substantially lighter in weight,” says Siemens Corporate Technology (CT) project manager Dr. Denis Saraev. This supermetal composite is particularly well suited for enhancing the performance of compressors, turbochargers, and motors.

Power cables made of nanostructured aluminum composites could one day replace cables made of pure aluminum. The new cables would have the same electrical properties while being thinner, thus saving material and costs, in particular when compared to expensive copper cables. TISNCM researchers produce the new material using a specially hardened planetary mill. Aluminum and C60 are milled in an argon atmosphere to the size of nanoparticles, with the powders combining during the process to form the new material. Blank expects that the development of aluminum material with fullerenes specifically for use in superconducting cables will soon be completed. Such cables could provide benefits in magnetic resonance imaging systems and compact motors, for example.

In a nearby lab, Siemens and TISNCM researchers are working on the refinement of materials, but this time the subject is so-called thermoelectric components. These are electrically conductive substances that can either generate an electric voltage and from that an electric current when a temperature difference is established at two locations, or generate thermal energy when a voltage is applied. The scientists have combined the thermoelectric reference material bismuth telluride with fullerenes. “We think that we will be able to generate a power output of about 50 watts from a 10 cm x 10 cm thermoelectric device with a temperature difference of 100 degrees Celsius,” says Saraev.

Such a development would enable many types of devices to generate electricity from their waste heat, thus substantially reducing their energy costs. For example, thermoelectric power generators could use not only the waste heat from gas turbines or steel mills, but also from the processors in computers or automobile engines and batteries - the latter could, for example, supply power for cooling and for information, navigation, and entertainment electronics. Devices equipped with this technology could also help to reduce the use of gases in refrigerators and freezers that are harmful to the climate - and quite incidentally to also reduce associated noise, because the technology is silent. The researchers have already reached a key milestone. “We have improved the thermoelectric ‘goodness factor’ by 20 percent with our nanostructured bismuth telluride,” says Saraev, “and that is currently tops worldwide.”

A Cushion of Air. Meanwhile in Moscow, about 30 kilometers away, Siemens is involved in another partnership. There, a CT team headed by Dr. Viacheslav Schuchkin is working with Dr. Alexander Vikulov from the Institute of Mechanics at Lomonosov Moscow State University on turbomachines mounted on air bearings that can replace conventional high-maintenance oil bearings in small turbines and compressors. Turbomachines rotating at speeds of up to 180,000 revolutions per minute can be used for such things as gasoline or diesel engines or in the oil industry for the treatment of wastewater with compressed air.

To produce maintenance-free bearings, the researchers designed extremely thin Tefloncoated lamellae. “At roughly 15,000 revolutions per minute, the lamellae reach the speed at which they lift off from the rotor’s axle by several thousandths of a millimeter,” says Schuchkin. “An extremely thin cushion of air forms between the bearing and the lamellae, thus allowing the turbine to run with essentially zero resistance. At that point it is maintenance- free.” In order to accomplish this, the researchers had to compute not only the optimal lamella size, but also the best angle of deflection and the ideal arrangement of the lamellae. In the future, it should be possible to apply this development to larger turbines as well.

Siemens Corporate Technology Russia is also active in the field of integrated gasification combined cycle (IGCC) power plants (see article “Underground Economy”). For instance, a team of CT researchers headed by Dr. Stepan Polikhov is hoping to use a new turbine technology to increase the efficiency of IGCC plants with carbon capture from today’s 30 percent to between 40 and 45 percent. Researchers at the Moscow Engineering Physics Institute (MEPhI) are providing substantial support. Synthesis gas - a mixture of carbon monoxide and hydrogen - is used as the fuel.

“The goal is to reduce carbon dioxide emissions of such turbines burning a gas mixture to the level of power plants fired with natural gas, while reducing the costs of CO₂ capture,” says Polikhov. Coal-fired power plants equipped with this technology would then be as clean as natural gas-fired power plants. The technical challenges are substantial, however. Synthesis gas contains large amounts of hydrogen, which causes flashback, flickering, or spontaneous ignition, all of which make it more difficult to achieve combustion that is as complete as possible and thus environmentally friendly. To address this problem, Polikhov and Professor Sergey Gubin from the MEPhI are working on a simulation of the gas turbine combustion process that incorporates critical parameters such as gas flow rates, gas mixture ratios, combustion chamber pressures, and combustion speed. Such simulations allow researchers to derive a burner design that is optimized for a specific gas mixture. Successful tests of a mixed-gas burner in a real combustion chamber have already been carried out.