超超临界1350MW二次再热机组汽轮机优化设计

Optimization design of steam turbine with double-reheat in a 1 350MW ultra-supercritical unit

为研究轴系布置和轴速对超超临界1 350 MW二次再热机组热效率和经济性的影响,构建了4种汽轮机型式的方案进行模拟和计算,分析了汽轮机排汽口数目、单双轴布置型式和轴速对机组经济性和热效率的影响。结果表明:对超超临界1 350 MW二次再热机组,宜优先选用4排汽,双轴,全、半速各一轴方案,厂净效率可达46.01%;其次可以考虑6排汽、单轴、全速方案;4排汽、单轴、全速方案和6排汽,双轴,全、半速各一轴方案皆因存在技术性限制或投资经济性劣势而不宜采纳。

To investigate the influence of shaft arrangements and shaft speed on efficiency and economy of the 1 350 MW ultra-supercritical double reheat unit,schemes of four different steam turbine types were built to carry out simulation and calculations.The effects of exhausting outlet number,single-and doubleshaft arrangement（cross-compound or tandem-compound）and shaft speed selection on the unit＇s efficiency and economy were analyzed.The results show that,for the 1 350 MW ultra-supercritical double-reheat condensing unit,a tandem-compound 4-flow steam turbine with a primary rotor portion running at 3 000 rpm and a secondary rotor portion running at 1 500 rpm is the best scheme,the plant net efficiency can reach up to 46.01%.Then the second choice is the scheme of a cross-compound 6-flow steam turbine with rotor portion running at full-speed.Due to the technical limitation and investment economic weakness,it is better not adopt the scheme of a cross-compound 4-flow steam turbine with rotor portion running at full speed and the scheme of a tandem-compound 6-flow steam turbine with a primary rotor portion running at3000 rpm and a secondary rotor portion running at 1 500 rpm.