Energy And Exergy Analysis Of Oxidation Of Coal For Generating Power In Supercritical Water

Coal is the main energy and important industrial raw materials in our country, it strongly supported the economic and social development of our country but it also brought serious environmental problems at the same time. Air pollution caused by emissions from coal-fired exacerbated the haze crisis in recent years. To solve the two major confrontation issues of coal "must use" and "environmental pollution" is to promote coal clean and efficient use of. The oxidation of coal in supercritical water is a new technology type of high efficient and clean. Coal and oxygen which dissolved in supercritical water will happen the oxidation reaction, and will produce a significant amount of heat, the reaction process does not produce the pollution gas such as SO2, NOx. The application of oxidation of coal in supercritical water to the thermal power generation process can achieve the purpose of energy saving and emission reduction.First, this article considered the problems of traditional coal-fired environmental and the advantages of supercritical water oxidation technology, put forward a circulatory system of direct oxidation of coal in supercritical water for power generation, The system uses oxidation reactor instead of the boiler in the traditional coal- fired power generation system, and combines the traditional coal-fired power generation process with the fuel system and the steam- water system. The coal in the feeding system and oxygen which dissolved in supercritical water will happen complex reaction in oxidation reactor, the high temperature and highpressure gas and supercritical water emitted by oxidation reaction to carry large oxidation heat into steam turbine power for expanding power, and then into the circulating water heating in the preheater. Finally, the water compied in the pool through the separation process and will be heated by the preheater, the heated waterthrough the pump into an oxidation reactor to complete the cycle.Secondly, according to related theoretical analysis of thermodynamics, the energy analysis and exergy analysis of the new power generation system are carried out in detail. It is concluded that the new system has the high energy efficiency and exergy efficiency, and analysis of the energy utilization of each device, puts forward oxidation reactor and preheater is a weak link.Last, the direct oxidation of coal in supercritical water generating system in this paper has been compared with conventional coal-fired power generation system and combustion of coal afer gasification in supercritical water thermal power generation, comparing the circulation system, according to the results of comparison shows that the energy efficiency of oxidation system is 12.2% higher than gasificationcombustion system, 14.5% higher than conventional system, the exergy efficiency of oxidation system is 19.5% higher than gasification- combustion system, 40.6% higher than conventional system, thus proved that the new system constructed in this paper for energy saving, high efficiency, and provides theory basis for the design and optimization for subsequent research of direct oxidation of coal burning for power generation in supercritical water system.