Investigation On The Performances For High Back Pressure Heating System Of Direct Air Cooling Coal Pulverized Power Station

With the development of heating technology,the mode of supplying heat by recycling waste heat from exhaust steam is becoming more and more diversified,such as absorption heat pump heating mode,DCK,high back pressure heat supply mode and soon on.Among these modes,high back pressure heating mode has gain attention due to its high-efficiency of recycling waste heat and simple heating retrofit advantage.Therefore,it's essential to investigate the performance of air-cooled unit heating system,which can provide theoretical guidance for subsequent heating retrofit and optimizing operation.In this paper,matrix analysis theory is established to make a mathem atical model for the direct air-cooled unit with 300 MW in the Shanxi province.Analyze the energy-saving effect of the heating retrofit,and it can be known that using high back pressure heat supply mode can recycle exhaust steam at 354.4t/h to heat,which can lower the heating rate at 824 kJ than the traditional heating mode and the coal consumption rate at 32 g.Analyze temperatures of supply and return water on high back pressure heating unit performance considering the actual temperatures of supply and return water.The result shows that no matter at the intial & end or peaking heating period,the lower the temperatures of supply and return water,the larger the quantity of recycled exhausted steam and energy utilization rate;the higher the temperatures of supply and return water,the larger the quantity of heating supply and recycled exhausted steam.On the condition of satisfying generating capacity,the higher the temperatures of supply and return water,the better the unit performance.At ambient temperature,Analyze the discipline of environmental temperature variation effects on high back pressure heating system under certain ambient temperature and calculate the best back pressure at different temperatures.The result indicates that the lower the environment temperature,the better the performance indexes.When the environment temperature is beyond 2 ?,the energy saving advantage of high back pressure heating system is not evident,so high back-pressure heating retrofit is applied in the region at low temperature.With the rising of environmental temperature,the best back pressure has a decreasing tendency,which provides the theoretical basis for the high back pressure heating system economic operation.