700℃先进超超临界机组概念设计方案研究

Study on conceptual design scheme of 700℃ advanced ultra supercritical unit

为大幅提高当前燃煤发电机组的发电效率,使700℃先进超超临界机组的净效率达到50%以上,对700℃超超临界机组概念设计方案进行了研究,分析了概念设计方案涉及的蒸汽初参数、机组容量、再热次数、主机选型方案、热力系统拟定、主要辅机选型和主厂房布置方案。结果表明:700℃超超临界机组概念设计方案推荐机组容量为660 MW,初参数为35 MPa/700℃/720℃的一次再热机组;锅炉拟采用超超临界参数变压运行螺旋管圈直流炉,单炉膛、一次中间再热、采用切圆燃烧方式、平衡通风、固态排渣、全钢悬吊结构塔式锅炉、露天布置;汽轮机拟采用单轴、一次中间再热、四缸四排汽;热力系统推荐采用带变频发电机的BEST小机回热系统,机组采用十二级非调整抽汽;主厂房推荐采用二列式、侧煤仓、汽轮机高位布置方案。700℃超超临界机组概念设计方案对我国建设更加高效和清洁的火力发电厂具有重要的参考意义。

To greatly enhance the efficiency of coal-fired power units and make the net efficiency of 700℃ advanced ultra supercritical(A-USC)unit higher than 50%,the conceptual design scheme of the 700℃ A-USC unit is studied.The initial steam parameters,unit capacity,reheat times,main engine selection scheme,thermal system formulation,main auxiliary equipment selection and plant layout scheme are analyzed.A primary reheat unit with capacity of 660 MW and initial parameters of 35 MPa/700℃/720℃ is recommended as the conceptual design scheme for the 700℃ A-USC unit.The boiler is planned to use the spiral tube coil once-through furnace with ultra-supercritical parameters and variable pressures.It is a tower boiler with all steel suspension structure,which has single furnace,single reheat system,circular combustion mode,balanced ventilation,solid slag discharge and open layout.The steam turbine is supposed to have single shaft,single intermediate reheat system,four cylinders and four steam rows.It is recommended to use the BEST steam turbine heat regenerative system with variable frequency generator.12-stage non-adjusted steam extraction system is applied in the unit.The main plant house is recommended to adopt the layout scheme with two-row,side coal bunker and high level arranged steam turbine.The conceptual design scheme of the 700℃ A-USC unit is an important reference for the construction of more efficient and clean thermal power plants in China.