水煤浆与干粉给料方式两种IGCC系统的(火用)分析

通过将煤气化过程与联合循环系统相结合,IGCC成为目前最有发展前途的洁净煤技术之一.但以往对IGCC系统的研究多集中联合循环或气化过程本身,而忽略了气化效率对系统整体性能的影响.为揭示气化过程与系统性能之间联系,本文对Texaco与Shell公司的两个IGCC系统实例分别进行了流程模拟和(火用)分析,并着重从热力学角度比较了系统煤气化部分的差异对系统整体性能的影响,得出结论:Shell煤气化技术与Texaco煤气化技术相比,气化过程的(火用)损失相对减小15%,冷煤气效率提高2.6个百分点,系统热转功效率上升2.1个百分点.本文研究成果为IGCC系统进一步改进提供了热力学基础理论支撑.

EXERGETIC COMPARISON OF TWO IGCC POWER PLANTS WITH DIFFERENT COAL FEED DESIGN

Integrated gasification combined cycle (IGCC) power plants are currently under development to provide a clean and efficient option for generating electric power from coal. To reveal the interaction between the gasifier and the system performance, from the exergetic viewpoint, we have compared two IGCC systems with different gasification island: Texaco configuration using slurry coal feed gasifier and Shell configuration with dry coal feed gasifier. With the aid of graphical exergy analysis, we have indicated some specific information on internal phenomena of these two systems. The results identifies the causes of performance difference between the two cases: the evaporation of the water in the slurry in Texaco gasifier deteriorates the match of the gasifier. Compared with Texaco gasifier, the exergy destruction in Shell gasifier is decreased by about 15%. As a result, the thermal efficiency of the Shell IGCC system is 2.1 percent points higher than that of the Texaco configuration. This investigation will be valuable for the development of next-generation IGCC.