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Russian Filter For Russian Exhausts

June 15, 2004

Automobiles manufactured in Russia are now often equipped with expensive American or European catalytic exhaust scrubbers - converters. However, according the opinion of researchers from the Mendeleyev Russian Chemical-Engineering University, Russian automobiles will be soon equipped with exhaust scrubbers manufactured in Russia.

Traditional exhaust scrubbers represent a depth filter produced from ceramic material - cordierite, which is covered by platinum, palladium and rhodium. The filter is installed before the silencer so that it purified exhausts from noxious gases.

Noble metals and the filter made of cordierite (which is not produced in Russia) are very expensive. Therefore, Russian chemists from the Mendeleyev Russian Chemical-Engineering University decided to make a more economical, domestically produced exhaust scrubbers based on new ceric catalyst that contains much less noble metals (ideally, none at all). These catalysts are assumed to cover an inexpensive ceramic cellular structure medium also developed in the Mendeleyev Russian Chemical-Engineering University.

Researchers at the Chair of Nonorganic Substance Engineering of the Mendeleyev Russian Chemical-Engineering University have utilized unique characteristics of ceric oxide. Chemists compare a ceric catalyst to a small chemical reactor. This small chemical reactor can operate in severe unstable conditions of automobile life. Accelerations, stoggages, in other words, various velocity steps of a motor-car influence the operating temperature of the car components, the temperature varying from three hundred to a thousand degrees.

Cerium is a rare-earth element, it is able to absorb oxygen required for automotive fuel oxidation. When the air-fuel mixture in the internal-combustion engine or the diesel engine contains excess oxygen, the ceric catalyst "absorbs" it. However, when the excess fuel is fed to the engine, oxygen gets scarce. At this point, cerium comes to relieve. Cerium is capable of not only absorbing oxygen, but also of giving it back at a required point of time.

How will such a material behave in the automobile? Gases with detrimental impurities and soot get from the engine to the converter installed before the silencer. Here, the ceramic cylinder covered by catalysts is ready to purify them. The catalysts convert detrimental carbon oxide, nitric oxides and carbohydrates into nitrogen, water and carbon dioxide, which are no harm to health or environment. The content of noxious gases and soot in exhausts decreases by more than ten times, and this is considered to be a very good result.

In addition, cerium is capable of reducing adverse effect of sulfur which is found in petroleum and fuels produced in Russia. The danger is that sulfur easily interacts with noble metals, this "spoiling" the catalyst. The researchers are currently starting the tests on catalytic converters.

Informnauka (Informscience) Agency