Extraction Heating Retrofitting And Utilization Of Extraction Steam In Shouyangshan Power Plant

With the propose of the peak carbon emissions and carbon neutral,the electricity industry must develop in the direction of low carbon,environmental protection,energy saving and high efficiency.Meanwhile,The state has also made unprecedented efforts to optimize the transformation of coal-fired power plants.With higher energy efficiency and lower cost,combined heat and power generation is one of the main technologies adopted by coal-fired power plants to save energy and reduce consumption.In this thesis,three extraction heating retrofitting schemes are proposed in view of the increase of thermal consumers and the low efficiency of the boiler caused by blending combustion of undersigned coal in Shouyangshan Power Plant.The three schemes are as follows.Scheme 1 is direct heating supply by extraction steam + #0extraction steam to heat the secondary air;scheme 2 is direct heating supply by extraction steam + #3 extracting steam to heat the secondary air;scheme 3 is extraction steam to heat the secondary air + extraction heating,i.e.comprehensive retrofit.The technical and economic analysis of the three schemes are performed.Compared with the other two schemes,the investment of the scheme 3 is higher.However,the benefit is the largest,the recovery period is the shortest,and the system is relatively simple,with the advantages of a large increase in secondary air temperature,strong adaptability in coal type and load adaptability,and the best energy-saving effect.Therefore,scheme3 is the best heat supply retrofitting plan for Shouyangshan power plant.On the basis of scheme 3,three practical extraction steam application schemes are further proposed in order to further improve the performance of the unit.And the process and economic evaluations of each scheme are carried out.The scheme of using extraction steam after heat exchange instead of three-extraction steam to heat the feed water of #3 heater has less investment and the shortest payback period;the scheme of using extraction steam to heat the air preheater recovery air + using the heated recovery air to increase the powder feeding temperature scheme has the highest investment and longest payback period;the scheme of using hot extraction steam after heat exchange to replace the super steam of the platen superheater as the blowing steam source of boiler soot has the least investment and a shorter payback period.Finally,the energy-saving and consumption-reducing effects and the economic benefits of the unit after the comprehensive retrofit and the deep utilization of the extraction steam are evaluated.After the retrofitting,a single unit saves 1,1993.4 tons of coal per year,with an average annual income of 9.115 million yuan.The boiler efficiency is improved,and the standard coal consumption rate for power generation is reduced.The total annual coal savings of a single unit is 4412.4 tons,with an average annual income of 3.353 million yuan.The economic effect is remarkable.The expanded application of extraction steam can also produce more additional economic benefits.Among them,the average annual income of a single unit for expansion and retrofitting of three extractions for heat is 3,053,000 yuan;the average annual income of a single unit for the optimization and expansion of sealed recovery air is 704,520 yuan;The expansion and retrofitting of soot blowing steam source can save about 112,700 yuan per year.Shouyangshan Power Plant proposed the retrofitting scheme of heat supply after using extraction steam to heat the secondary air at the side of the boiler for the first time.The results of this thesis have certain reference significance for other thermal power units on extending heat capacity,optimizing unit system and increasing the efficiency of the boiler.