Integrated Analysis Of Technical, Economic And Environmental Performance For APFBC-CC System

The advanced pressurized fluidized bed combined cycle(APFBC-CC) is one of the most promising clean coal power generation technologies. For developing the clean coal technologies, it is important to study the representative system on the technical, economic and environmental performance.Based on the theory of"Life Cycle Assessment", the evaluating method of coal-fired power generation on tech-economic performance and environmental impact is established. The real cost of coal-fired power generation can be calculated including environmental impact factor.The three representative kinds of APFBC-CC system, which are pressurized gasification pressurized char combustion system (APFBC-CC/I), pressurized gasification atmospheric char combustion system (APFBC-CC/II), and atmospheric gasification atmospheric char combustion system (APFBC-CC/III), and PFBC-CC system used natural gas supplementary combustion (NGSC-PFBC-CC) are analyzed and optimized on the thermodynamic, tech-economic and environmental performance. Some valuable results are obtained. (1) The system of both APFBC-CC/I and APFBC-CC/II possess excellent integrated performance, APFBC-CC/I is the best of all, whereas the performance of APFBC-CC/III is inferior compared with the others. Base on supercritical and ultra-critical steam parameter, the APFBC-CC system thermal efficiency, environmental and economic performance can be improved more. (2) The method of high temperature preheating gasification air and steam is first used in APFBC-CC system. It is available to improve the heating value of syngas and system efficiency by high temperature preheating gasification air and steam. This approach to produce higher heating value syngas has significant advantages in the low-quality coal. (3) The system integrated performance optimization results show that the lowest real cost of APFBC-CC/I and APFBC-CC/II are at carbon conversion 0.7-0.8, however APFBC-CC/III is at 0.55-0.6. (4) The NGSC- PFBC- CC system can increase the gas turbine inlet temperature, and greatly increase net cycle efficiency and reduce environmental emission. The net efficiency of NGSC- PFBC-CC system is 3.4~4.3 percent point higher than the combination efficiency of the conventional coal-fired plant (PC+FGD+DeNOx) and the natural gas combined cycle (NGCC), consumed the same amount of fuel. Due to the price of natural gas is more expensive than coal, and the real cost of this system is a little higher than APFBC-CC system. The natural gas consumed should be controlled in a reasonable level. (5) Compared with conventional PC+FGD+DeNOx plant, APFBC-CC and NGSC-PFBC-CC greatly save energy consumption, improve economic performance and reduce environmental emission. Thus both of all possess great development foreground.