Among fuel raws hard coal is still one of the most important factors of energy supply and economic stability of Russia. At present about 270 mn tons are being extracted. But unfortunately, mining and use of coal at heat and electric power plants and boiler houses result in severe pollution of atmo-, hydro- and lithosphere*. It is no coincidence that for a long time many scientists have been trying to reduce negative environmental impact of extraction and use of this solid fuel.

The answer was found in the 1930s, when national engineers offered to apply an underground coal gasification technology (UCG) which included both extraction and processing and allowed to produce fuel gas (final product). And in the 1950s the Yuzhno-Abinskaya station "Podzemgaz" commissioned in Kuzbas, in 1963 the second similar enterprise started operating in the town of Angren (Uzbekistan). In the 1970s - 1980s the idea aroused interest abroad: some coal-mining countries purchased licenses for this technology.

So, how is it being used today? Is it possible to use the obtained experience and present-day knowledge in order to increase gas component of the fuel balance using the UCG? The administration of the Kemerovo Region addressed these questions to the scientists of the RAS Siberian Branch Institute of Coal and Coal Chemistry.

It was decided to hold a special seminar (it took place in Kemerovo in the middle of 2004) to find the answers. Apart from the members of the aforesaid scientific research institute, it was attended by representatives of the branch of the Institute of Solid Body Chemistry and Mechano-chemistry Institute of Thermophysics, RAS Siberian Branch Kemerovo Scientific Center, Yuzhno-Abinskaya and Angrenskaya stations "Podzemgaz".

S. Lazarenko, Dr. Sc. (Tech.), Chief Research Assistant of the RAS Siberian Branch Institute of Coal and Coal Chemistry, was one of the first to speak. In his view, the UCG technology opens up new possibilities in mining coal strata of difficult mode of occurrence. He emphasized that this technology can be applied in a close and medium-term perspective. But even now it is possible to perform a high-pressure gasification of a deep horizon coal and carry out "compressor-free" transportation of the final product up to 200 - 250 km away from the mining spot.

The scientist mentioned that at present an overall development of the underground coal gasification is the most efficient way to increase gas component of the fuel balance for the Kemerovo Region. The calculations showed that building a gas pipeline, for example, from the Tyumen Region to Kuzbas, would be several times more expensive than construction of necessary number of plants producing the same quantity of fuel oil underground. The UCG technology was also advocated by A. Vorogov, former director of the Yuzhno-Abinskaya station "Podzemgaz". He said a unique experience was acquired during the forty years of its operation. The first gas generator was put into operation by a "combined" method using underground works, but in the 1970s - 1980s a new technology was launched. Besides, hydraulic fracturing of formation and directional drilling of slanted horizontal wells using high-speed downhole hammer drills with telesystems were introduced into production. That experience allowed to set a standard gas quality criteria. The minimum heat value of gas at the Prokopievsko-Kiselyovskoye field was determined at the rate of 900 kkal/kg.

In 1966 the station produced 488 mn m³ of gas - the maximum quality produced for the whole period of operation. It was used by seven industrial enterprises.

Unfortunately, in 1996 the station was liquidated: slump in gas consumption in summer periods affected its cost-performance ratios.

An optimistic forecasts concerning development of the UCG technology were made on the part of representatives of the Angrenskaya station "Podzemgaz" which is still operating. The station is using underground gas generators to manufacture products. The efficiency of production is about 2,500 m³ /h for one well.

Technical and economic analysis of operation of the enterprise showed: combustion of gas produced under the UCG technology in the amount of 30 mn m³ a year saves 27,000 tons of fuel oil. Moreover, ecological indicators are improving which reduces payments for discharge of pollutants in the air by more than 70,000 dollars; soil is not stripping which is characteristic for open-cut gas mining; transportation and discharge expenses are reducing; harmful and dangerous labor conditions of miners in the working face are eliminated. At the same time participants of the seminar pointed out disadvantages of the UCG.

Nauka v Sibiri (Science in Siberia), 2004

Prepared by Ya. SIBIRTSEV

* See: A. Vorobyov, T. Chekushina, "Crisis of Mineral Raws: Perspective?", Science in Russia, No. 4, 2003; Yu. Izrael, "Threat of Climatic Catastrophe?", Science in Russia, No. 4, 2004. - Ed.

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