Technology Research On The Parameter Upgrading Project From Subcritical To Ultra Supercritical For 600MW Level Power Plants

This article mainly aims at supercritical transformation for 600 MW level subcritical units.Taking a 660 MW subcritical unit in north China as research model,combined with its main parameters and layout of the thermal system,did the calculation of heat balance,worked out the main hot economic indicators.This paper used STEAM PRO and STEAM MASTER to calculate supercritical thermal systems,combined with the practical experience of engineering,determined the the main parameters of the thermal system: the rated power of the unit is 860 MW,the main steam parameter is 31 MPa /600?/566?/538?,the steam turbine adopts the secondary reheat and the biaxial arrangement.According to the different driving mode of the boiler feed pump,the "steam feed pump" and "High pressure shaft drive feed pump " two ultra-supercritical transformation program have been designed.Through modeling in the software,following conclusions are drawn:(1)Through the ultra-supercritical transformation,the unit heat rate decreased by about 500kJ/kWh,whole plant efficiency increased by nearly 4%,reducing the standard coal consumption by about 30g/kWh;(2)The program of high pressure shaft driven feed pump is better than the other program,the difference of heat rate difference between the two is about 20 kJ / kWh.Base on relevant standards,the cost of the two projects has been estimated,furthermore,the economics of the project is evaluated by the static investment payback period analysis.With the analysis results,this paper concluded that the economic feasibility of the two ultra-supercritical transformation schemes is fine.