PROCESS SIMULATION AND ENERGY ANALYSIS OF OXY-COAL COMBUSTION STEAM SYSTEMS (OCCSS) WITH NEAR-ZERO EMISSIONS BASED ON COAL GASIFICATION

摘要

Oxy-coal combustion steam system with near-zero emissions (OCCSS) is a new type of power generation system, which is able to satisfy the demands for high efficiency utilization of coal and control of CO_2 emissions. It is necessary to study the characteristics of the new system, since both the combustion mode and the working medium are different to the power systems utilizing conventional combustion. In the present paper, we report the process simulation of a conceptual OCCSS based on coal gasification, as well as comparisons with a conventional combustion and an oxy-fuel combustion. The model of the system was built and parametric studies showed the pressure of burners and ratios of fuel have effects on the performance of the system. The net efficiency of power generation increases quickly with the increasing pressure of the gas generator followed by a slower decrease. The net efficiency of the system increases with the increasing fuel ratio to a burner which is set before any burners with decreasing ratio. Otherwise, it decreases. The energy analysis shows the net efficiency of OCCSS is higher than the conventional combustion system and the oxy-fuel combustion system.