Effect Of Ceramic Membrane Method For Flue Gas Water And Waste Heat Recovery On The Operating Economy Of Coal-fired Power Generation System

Coal-fired power generation is still an important pillar of current China’s power industry.Under the background of carbon neutrality,deep energy conservation and emission reduction is an important direction of coal-fired power generation.Flue gas from the plants after wet desulfurization contains a large amount of water vapor and heat.The ceramic membrane method for water and heat recovery from flue gas has the advantages of less corrosion and pollution in the harsh flue gas environment,showing broad development prospectsThis dissertation focus on the ceramic membrane method for water and heat recovery from flue gas.A mathematical model for the heat and mass transfer process of ceramic membranes is constructed.The ceramic method is combined with the thermal system,with the recovered water used as plant make-up water,and the recovered heat used to preheat the return water of the heating network.A thermal system model for the entire plant combines the ceramic membrane method for water and waste heat recovery is established.Based on a demonstration project,the thermal system model for the entire plant is built with the matrix method.The lithium bromide absorption heat pump is coupled to the ceramic membrane water and waste heat recovery system,making full use of the recovered waste heat.The effects of flue gas flow,cooling water flow,and cooling water temperature on recovery performance,the coal saving rate,and steam extraction for heating are analyzed.This dissertation is committed to explore the change rules of water and heat recovery performance and thermal economy of the whole plant under different working conditions.Results indicate the increase of flowrate and the decrease of cooling water temperature will increase the water and heat recovery flux of the system.However,due to the decrease in the cooling water outlet temperature reduces the performance of the heat pump,the coal saving rate is also reduced.The maximum water recovery flux is 35.74 kg/(m2·h),and the maximum coal saving rate is 1.37 g/(kW·h).The annual coal saving capacity is 677.84 t and the annual water saving capacity is 233254.04t.Based on the techno-economic analysis of the system,and the investment payback period and net present value of the system under different operation conditions are compared.The shortest investment payback period is 5.2 years.