Analysis And Research On Economical Efficiency Influence Of Power Unit About Supercritical Boiler's Low Pressure Economizer

As the development of the power industry, installed capacity has greatly increased. At the same time, consumption of fuel has greatly increased which made a claim for increasing exploitation of fuel and transportation. Discharge of pollutant is on the increase in air. Contradiction of economic development and environmental resources defies solution."Reduce energy consumption per GDP"and"decrease total quantity of pollutant discharge"are binding force index in planning outline of the twelfth five-year plan. so, research on how to do boiler reforming ,decrease coal consumption and improve economical efficiency of unit is of importance.In this thesis, do research on Fuxi 600 MW supercritical coal-fire boiler-turbine power unit. Design and comply boiler's thermodynamic calculation program bases on modular method, which supervises and stores relational database with subroutine and functions to do verifying calculation for different coal sample. Data input and output are finished by the EXCEL software. On the basis of calculation result, the regularity for change of boiler system thermodynamic property in combusting different working condition is studied. At the same time, comply turbine's variable working condition thermodynamic calculation program which let boiler and turbine as a whole. Do analysis and research on economical efficiency influence of power unit about supercritical boiler's low pressure economizer (change water temperature). By comparison and data, raise several alteration proposals, which are objective analysed to choose a best one.1.Take Fuxi power unit as a example, do analysis and research on economical efficiency influence of power unit about supercritical boiler breech which low pressure economizer (change water temperature).There is conclusion as follow,1.1 Elevating feed water temperature can reduce energy and fuel consumption, but it is trouble for alteration in worksite.1.2 Low pressure economizer after air preheater can save energy and fuel consumption.A. The scheme's strong suit is that influence to boiler operation is little.B. Disadvantage is lower diathermancy, larger heat transfer area and harder to arrange; It is easy to bring low temperature corrosion and coal ash jam.1.3 Low pressure economizer before air preheater can save more energy and fuel consumption. Because of higher diathermancy , less heat transfer area and easier to arrange, structure is simple and construction is convenient, but it need to control hot air temperature depending on circumstances.2 The thesis found the cause of reheater overheating about Qinghe Power Plant 600MW supercritical boiler according to fluid dynamics and steam by program. At the abse of research on Fuxi Power Plant ,take Qinghe Power Plant 600MW supercritical boiler as a example, measure of decreasing reheater heat transfer area and spaning low pressure economizer before air preheater can do a good deed as following:2.1 There is no reheater steam water injection in plan condition.2.2 Fuel consumption decrease 8.795 g/kwh, that is 3.02% of whole fuel consumption, in TMCR.