Four Stage Back Pressure Exhaust Steam Utilization System and its Performance Analysis
A four stage back pressure depleted steam deep utilization system suitable for peak shaving operation is proposed for a 600MW indirect air-cooled unit,which utilizes a large steam injector on the basis of high back pressure heating.Effectively solving the problem of reducing the low load exhaust steam heating capacity of cogeneration units,and improving the exhaust steam heating capacity of units under low load.Experimental research was conducted on the heating characteristics of a two-stage backpressure exhaust steam heating system,and it was found that the unit backpressure and circulating water temperature are the key factors affecting the utilization of exhaust steam.A four stage backpressure exhaust steam heating system energy consumption analysis model was established with the goal of minimizing the heat loss of steam turbine exhaust.The performance of the four stage back pressure exhaust steam deep utilization system of a 600MW unit under peak shaving operation during different heating periods was calculated and analyzed using an energy consumption analysis model.In the low load section,the back pressure on the high-pressure side is limited by the exhaust flow rate of the turbine.Reducing the back pressure on the low-pressure side through a circulating cooling system can improve system energy efficiency.Whether compared to the conventional exhaust heating method or the second stage back pressure exhaust steam heating method,the heating capacity of the fourth stage back pressure exhaust steam deep utilization system under low load is significantly improved.Compared to the two-stage backpressure exhaust steam heating system,the fourth stage backpressure exhaust steam deep utilization system can reduce the power generation output of the unit by 131MW while meeting the external heating needs.
万方数据
维普
