Research On Energy Consumption Diagnosis Of 600MW Supercritical Unit

Thermal power generation is the main force in China's current power generation industry,and the 600MW thermal power unit accounts for the main position of the thermal power unit.In order to promote the construction of an environment-friendly society,improve the current situation of serious resource consumption and environmental degradation and narrow the gap with international advanced power companies,it is imperative for the 600MW unit to conduct energy consumption diagnosis research and propose transformation proposals.This paper takes the "13th Five-Year Plan for Energy Saving and Emission Reduction Comprehensive Work Plan" issued by the State Council in 2016 as a background,taking the 600MW super-critical unit as an example,and researching the problem that the coal consumption and the plant's power consumption rate are higher than the required value.The main content of the thesis is divided into two aspects.Firstly,based on the operating data and design data of four different typical conditions of 300MW,450MW,560MW and 600MW,the on-line thermal calculation and energy consumption analysis of the unit are carried out to determine the main factors and reasons of energy loss;the second is to propose modifications of the typical thermal system,and use the thermodynamic method to evaluate the energy-saving effect of the transformation measures.The research results show that the cause of high-coal-consumption of the unit is:the efficiency of each cylinder of the turbine,the temperature of the main steam,the pressure of the main steam,the temperature of the reheat steam is lower than the design value.The steam pressure of the small steam turbine,the back pressure of the unit,and the four pumping and the flow of the small machine is high,the flow rate of the four pumping to the auxiliary steam header is large under high load,and the re circulation leakage rate of the feed pump is too large;the carbon content of the large slag of the boiler,the air leakage rate of the air preheater,the exhaust gas temperature,and the exhaust oxygen The amount is too high,the inlet air temperature is low;in terms of power consumption of the plant,the air preheater has a differential pressure,a large air leakage rate,a poor heat transfer effect,and a large amount of smoke.In view of the above problems,a transformation plan is proposed:for the feed water pump re-circulation valve,it is recommended to adopt a multi-stage small-hole throttling structure to modify the valve flap structure,increase the valve guide and the pressure relief groove to adjust the gap between the high and medium pressure cylinder shaft seals,and adjust the valve front Manual door is changed to electric door to reduce leakage;for turbine shaft seal system,it is recommended to adjust the gap between the high and medium pressure cylinder shaft seal to the design value and design lower limit specified by the manufacturer to reduce the shaft seal steam flow;It is recommended to reduce the commissioning of the reheater's desuperheating water;for the heater air source,it is recommended to change the heater air source to four-stage extraction;for the steam soot system steam source,it is recommended to use the soot blowing source.The stage superheater outlet is transformed into a low temperature reheater outlet steam.It has been verified that the coal consumption rate of the power supply can be reduced by about 7.876g/kW.h after the transformation,and the effect is obvious.The purpose of this paper is to guide the site to make reasonable adjustments to the unit and operating parameters,optimize the performance of the unit,fully exploit the energy saving potential of the generator set,and improve the energy efficiency of power generation enterprises.