The coal and biomass coupling power generation technology is considered as a promising technology for energy conservation and emission reduction. In this paper, a novel coal and biomass indirect coupling system is proposed based on the technology of biomass gasification and co-combustion of coal and gasification gas. For the sake of comparison, a coal and biomass direct coupling system is also introduced based on the technology of co-combustion of coal and biomass. The process of the direct and the indirect coupling system is simulated. The thermodynamic and economic performances of two systems are analyzed and compared. The simulation indicates that the thermodynamic performance of the indirect coupling system is slightly worse, but the economic performance is better than that of the direct coupling system. When the blending ratio of biomass is 20%, the energy and exergy efficiencies of the indirect coupling system are 42.70% and 41.14%, the internal rate of return (IRR) and discounted payback period (DPP) of the system are 25.68% and 8.56 years. The price fluctuation of fuels and products has a great influence on the economic performance of the indirect coupling system. The environmental impact analysis indicates that the indirect coupling system can inhibit the propagation of NO_x and reduce the environmental cost.

煤和生物质耦合发电技术被认为是节能减排的有前途的技术。本文基于生物质气化和煤与气化气共燃烧技术，提出了一种新型的煤与生物质间接耦合系统。为了进行比较，还基于煤和生物质的联合燃烧技术引入了煤和生物质的直接耦合系统。模拟了直接和间接耦合系统的过程。分析和比较了两个系统的热力学和经济性能。仿真表明，间接耦合系统的热力学性能稍差，但经济性能优于直接耦合系统。当生物质混合比为20％时，间接耦合系统的能量和火用效率为42.70％和41.14％，系统的内部收益率（IRR）和折现投资回收期（DPP）为25.68％和8.56年份。燃料和产品的价格波动对间接耦合系统的经济性能影响很大。环境影响分析表明，间接耦合系统可以抑制NO的扩散_x并减少环境成本。