Operation Research Of 350MW Supercritical Unit Flue Gas Heat Utilization Circulating Water System

Thermal power units currently facing the dual pressures of pollutant emission control and the coal consumption indicators. LGGH( Longking gas-gas heater) flue gas waste heat utilization system is a new flue gas heat recovery- reheat apparatus, it can improve efficiency of precipitator and desulfurization and conservation area. The use of the heat transfer medium(water) exchange heat with the flue gas through a high / low-temperature heat exchanger. It reduces the Electrostatic Precipitator inlet flue gas temperature, while increasing net flue gas temperature after desulfurization to achieve the ultra-low emissions. Thus, coal-fired power plant air pollutant removal and cooperative control efficiency is one of the strategic topics at the forefront of the current international energy field of the environment, also to be hotspot and difficulty research.This article describes the Flue gas waste heat utilization system of LGGH on a new 350 MW supercritical unit. The system is rarely in the domestic unit, the actual operation is lack of reference, circulating water system operation needs to be further studied. In the automatic control system, flue gas has temperature feedback lag, long response time and other shortcomings, it can't be quickly and efficiently adjust the circulating water flow to the optimum value, according to the load change units, so that the net flue gas discharge temperature to achieve the desired value. Therefore, with this system for the study, the first establish the mathematical model of the system, then based SimuWork simulation support platform, establish the system configuration models with different equipment. System circulating water flow simulation run research results of the system.It is concluded that the system under different conditions to achieve the optimal heat transfer effect of the optimum circulating water flow curve fitting.The curve data is used for guidance field operation and automatic control system used for the booster pump frequency change of water flow in lock value, as the feed forward value of the inverter control of pump, fill in the control system. Effectively overcome the effect of hysteresis in the automatic control system, improve the quality control for automatic regulating and guiding the actual operation is of great significance, it has a certain reference value for the actual optimization and operation for the future.