Study On Optimization Of Flow Field And Diversion Plate Structure Of Low Temperature Economizer In Coal-fired Power Plant

Instaling low temperature economizer in the tail flue of utility boiler can reduce boiler exhaust gas temperature,reduce boiler boiler exhaust heat loss,effectively improve energy utilization ratio of thermal power plant and reduce power generation cost.The instalation of low temperature economizer improves the thermal efficiency of the boiler and brings some problems.Therefore,it is of great practical value to set up the low temperature economizer and put forward the optimization scheme for the realization of energy saving and emission reduction.In this paper,a practical project of installing 2 × 330 MW units with a low-temperature economizer in a power plant is carried out.According to the actual size of the flue gas stack,flow field structure optimization analysis of intermediate heat exchange equipment and the inlet/outlet of the low-temperature economizer was conducted.Results show that for the middle heat exchanger of low temperature economizer,three baffles arranged along the Z axis can make the gas flow velocity in the Z axis of the inlet section of the economizer tube more uniform.However,the inlet section of the economizer with XY sectionthe air distribution is uniform,there is no need to add deflector in the direction.For the both flue gas stack at inlet and outlet of the low-temperature economizer,three baffles added in the bend flue stack enteringthe economizer can make theflow rateof the flue gas inlet section of the economizer more uniform.The performance test of on-site instalation of low-temperature economizer in two 330 MW units(No.5 and No.6)finds that the actual flue gas resistance exceeds the design value,but the outlet flue gas temperature is controlled at 100?,the air leakage rate is less than 0.5%after instaling the low-temperature economizer.Setting the low-temperature economizer can effectively reduce the temperature of the flue gas entering or leaving the precipitator and improve the dust removal efficiency,which result in reducing the mass concentration of particle matter at the outlet of the precipitator.The instalation of two sets of low-temperature economizer units can significantly reduce coal consumption under different loads.