Thermal Economy Analysis of Supplementary Steam Regulating System for 1 000 MW Ultra-Supercritical Unit under Full Conditions
In order to solve the problem that the thermal economy of large-capacity ultra-supercritical coal-fired units decreases significantly under low load conditions,this paper proposed a steam turbine supplementary steam regulating system,which reduced the flow area of the high pressure cylinder front section and increases the bypass steam supplement.Based on the MATLAB/Simulink simulation plat-form,the system simulation model and thermodynamic analysis model of a 1 000 MW ultra-supercritical coal-fired unit were built,and the influence of the supplementary steam rate and the supplementary steam pressure ratio of the steam turbine on the thermal economy of the unit was analyzed.The results show that when the supplementary steam pressure ratio of the steam turbine is constant,increasing the supplementa-ry steam rate of the stream turbine can reduce the coal consumption rate of the unit,and the lower the load,the more obvious the energy saving effect;when the load rate of the unit is 20%,and the supple-mentary steam pressure ratio and the supplementary steam rate are 0.95 and 0.60,the steam turbine in-let pressure can be increased by about 6 MPa using the steam turbine supplementary steam regulating sys-tem,and the coal consumption rate of the unit is reduced by about 20 g/(kW·h);taking the actual op-erating load of the unit for two months as the boundary condition,the total coal consumption of the unit can be reduced by about 1.8%.
deep peak shavingultra-supercritical unitsupplementary steam regulationthermal econ-omy