四阀亚临界机组中低负荷区域运行提效研究

重新设计喷嘴组的通流面积后,提高机组在中低负荷区域的运行压力。75%左右负荷,机组在二阀点下运行,主汽压力从13.56 MPa提高到16.7 MPa。由于部分进汽度有所增加,部分进汽损失的增加,高压缸的效率下降了0.48%。主汽压力提升,高压缸做功量增加25.8 kJ/kg。从单位蒸汽做功量变化和吸热量变化上进行分析,75%左右负荷下机组热循环效率提高0.62%,机组供电煤耗下降3.5 g/kWh。所以,通流面积重新设计后结合蒸汽参数的变化,机组在中低负荷区域的经济性明显提升。

The Research of Improve Efficiency for Four-valve Subcritical in the Low Load Region

After redesign of nozzle group flow path area,the operating pressure of the unit in the middle and low load region can be improved.At around 75% load,the Unit was running under the two-valves opening condition,the main steam pressure was increased from 13.56 MPa to 16.7 MPa.As the partial admission degree increased,the loss increases,and the high pressure cylinder efficiency would be droped 0.48%.With the main steam pressure increasing,the working quantity of the high pressure cylinder increased 25.8 kJ/kg.Analyzing on the steam power changes and heat changes,the unit thermal cycle efficiency improved 0.62% under 75% load.The coal consumption of power supply reduced by 3.5 g/kWh.Therefore,with the flow area redesigned and the steam parameters optimization,the operation efficiency of the unit in the middle and low load region was improved significantly.