提高超临界和超超临界机组发电效率的关键技术

根据国内外超临界和超超临界机组的研究结果和运行数据,比较全面地阐述了提高超临界和超超临界机组热效率的关键技术。主要包括:提高机组蒸汽参数;采用优化的变反动度的新型汽轮机叶片;采用可调间隙的汽封结构;降低凝汽器背压;增加回热加热级数,提高给水温度;采用内螺纹管水冷壁降低水冷壁质量流速,减小水冷壁流动阻力;控制过热器和再热器减温水量;开发高效燃烧低污染排放和低负荷无油稳燃的燃烧技术;采用带有循环泵的启动系统,加快机组启动速度;优化运行方式;优化辅机配置。新技术的综合采用可提高新一代超临界机组的发电效率,降低发电煤耗。最后提出了国内电站实际需要研究的课题。

The Key Techniques to Improve the Generating Efficiency of Supercritical Unit and Ultra- Supercritical Unit

Based on the study results and operation data of supercritical pressure units and ultra-supercritical pressure units at home and abroad, this article expatiates all-sidely the techniques that can improve the generating efficiency of supercritical unit and ultra -supercritical unit, mainly including: to raise the steam parameters;to adopt the optimized new type steam turbine blades with variable reaction degree;to adopt the steam sealing configuration with adjustable clearances; to decrease the back pressure of condenser;to inerease the stages of regenerative heaters,to raise the temperature of feed water;to adopt the internal ribbed tube wall to decrease the mass flow velocity of waterwall,to decrease the flowing resistance of water wall;to control the attemperating water quantity of superheater and reheater; to research and develop the high efficieney combustion and low pollution emission technique and the partial load steady combustion technique without oil firing aiding;to adopt the start-up system with cireulating pump to increase the start-up velocity; to optimize the operation modes; to optimize the auxiliary equipment allocation.The adoption of these new techniques will improve the generating efficiency and reduce the coal consumption of new generation supercritical units. For realizing these new techniques,the research topics are put forward in the article