| Because of the raising of fuel cost and the reduce of profit,the energy saving of coal-fired power unit has faced serious situation.During installation and commission, electricity price of new coal-fired power unit was20%less than during commercial operation. In order to improve the heat economic performance of supercritical direct air-cooling unit during installation and commission,optimization for the exhaut steam pressure and main steam pressure was carried out.In order to modulate exhaut steam pressure better for improving the heat economic performance,take cooling unit of air cooling island as object of study.By building mathematical model a comprehensive analysis has been conducted to investigate the influence of some key parametric on the steam turbine power incremental output,including cooling unit steam pressure, rotary speed of the fans,and ambient temperature. The optimal target is maximal differential value which between the steam turbine power incremental output and the fan power consumption.the results indicate the optimal steam pressure in cooling unit and the fans optimal rotational speed in different working conditions, and provides references for economic operation of direct air-cooled power plants.Based the safety and stability,during installation and commission the new power unit’s mode of distributing steam was single valve,and when under low load the operation mode of was throttle-sliding pressure. In order to improve the heat economic performance of steam turbine during capital construction,based on operating characteristic in this time,a comprehensive analysis has been conducted to investigate the influence of main steam pressure on the feed-water enthalpy, the heat requirement of boiler, and the steam turbine power output,and mathematical model of optimal main steam pressure has been built.Through the calculation for the home-made660MW units,it is demonstrated that the model with applicability satisfy the actual requirement of project. |
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