Use of underground coal gasification gas for co-production of electric power and synthetic liquid fuel

The study is relevant due to increased interest to the underground coal gasification technologies (UCG). The interest is determined by the depletion of world oil and gas reserves, the significant amount of coal deposits in various countries of the world, the growing energy demand, as well as the threat of global climate change. The possibility to use technologies of underground gasification of low-grade coal with complex geological environment is huge. Recently, interest to UCG has grown dramatically. In contrast to all major programs of the 20th century, this unprecedented interest is mainly stimulated by private capital in response to high oil and energy prices. Thus, the studies of UCG are carried out. And more than 30 tests are planned in Australia, China, India, South Africa, New Zealand, Canada, and the United States. The development of competitive gas-based technologies of production of electricity and synthetic liquid fuels is a high-priority task. The studies have been carried out using a mathematical model of the unit for the production of electricity and methanol. To design a mathematical model, a software, or the system of machine programs development (SMPP) has been used. It has been developed at Melentiev Energy Systems Institute of Siberian Branch of the Russian Academy of Sciences (ESI SB RAS). The article presents the results of the study of the use of UCG for the coproduction of synthetic liquid fuel (methanol) and electricity. A detailed mathematical model of electricity and methanol production unit has been developed. Based on the model, technical and economic optimization of the schemes and parameters has been carried out. It made possible to estimate the competitiveness conditions of the proposed method of coal processing. In addition, the sensitivity of the economic indicators of the unit to changes in external conditions has been studied. Based on the results of the analysis of the cost of diesel fuel in the eastern regions of Russia, the authors have made the conclusion that at present methanol produced by the energy technological unit is as competitive as delivered expensive diesel fuel. The introduction of such systems is economically reasonable in the near future.