Study On Diagnosing Energy Method For Steam Turbine And Auxiliary Systems In 300 Units

Thermal power plant,which is the pillar of China's electric power industry,provide important support for the domestic economic development and play an important role in the energy saving and emission reduction of the country.At present,energy-saving reforming of the equipment or system is a vital mean for thermal power plant to improve energy efficiency.Since the technical innovation of thermal power plant has become more difficult,it is harder to tap energy saving potential through transformation of technology,so research on diagnosis of system energy saving will become the main direction in the following study of energy saving for thermal power plant.It is essential to study the diagnosis of steam turbine and its auxiliary system energy saving because the steam turbine and its auxiliary system are the most important system of the thermal power plant,and the most energy saving potential system as well.The steam turbine of 300 MW thermal power plant is model N300-16.7/538/538,produced by Harbin Turbine Co.Ltd.,and the unit adopts sub-critical,intermediate reheat,double-cylinder and dual-exhaust,condensing steam turbine,the designed heat consumption rate of the unit after flow path retrofit is 7923.3kJ/(kW·h),but the heat consumption rate under full load is between 8200-8300kJ/(kW·h)in practice,after considering the parameter deviation,flow deviation and the temperature of cycled water,the heat consumption rate is still 200-250 kJ/(kW·h)higher than the designed value.This paper comprehensively studied the operation conditions of steam turbine and its auxiliary system of 300 MW power generation,and main research work and conclusions have been summarized as follows:1)Steam turbine and its auxiliary system consist of steam turbine proper,regenerative heating system and cold-end system,and their actual operation conditions have been systematically studied.2)Fault Tree Analysis Method has been applied to examine the energy efficiency of steam turbine proper,regenerative heating system and cold-end system,respectively.The minimum cut sets were divided into two ranges i.e.operation optimization and maintenance.Furthermore,the minimum cut sets of three mentioned systems have been integrated according to Boolean Algebra algorithms.3)Based on the analysis of statistical data and Fault Tree of energy efficiency,theprimary causes of high energy consumption and low energy efficiency of steam turbine and its auxiliary system of 300 MW power generation have been obtained.Finally,it was also observed that the operational issues of steam turbine and its auxiliary system of 300 MW power generation included low temperature of reheating steam,high terminal temperature difference of heaters,high shaft seal leakage rate of high&intermediate pressure cylinders and low clean co-efficiency of condenser.