Application Study On Recovery Of Moisture And Waste Heat From Flue Gas By Ceramic Membrane Method

The composite ceramic membrane can recover moisture and waste heat from flue gas,which has the advantage of a relatively good recovery effect.In this paper,the heat and mass transfer mechanism of waste heat and moisture in ceramic membrane recovery was studied from both experimental and numerical simulations.The ceramic membrane flue gas moisture and waste heat recovery test were carried out in the flue gas after desulfurization.The effects of inlet flue gas temperature,inlet cooling water temperature,flue gas flow rate,cooling water flow rate and water vapor mass fraction in the inlet flue gas on moisture and heat recovery were studied.The experimental results show that increasing the flue gas flow rate,increasing the cooling water flow rate,increasing the inlet flue gas temperature,reducing the inlet cooling water temperature,and increasing the mass fraction of water vapor in the inlet flue gas can increase the amount of recovered water and heat,but Increasing the flue gas flow rate will reduce the recovery water rate.During the experiment,it is also found that about 1/4 of the condensed water is condensed from the outside of the membrane and is not recovered to the cooling water side,but flows out of the drain valve.According to the above experimental results,the corresponding heat and mass transfer theoretical model is established.By adding corresponding mass source items,energy source items,momentum source items and component source terms to the Fluent software,the condensation and recovery process of water vapor in the ceramic membrane is simulated.Finally,the origin of the condensed water outside the membrane is theoretically explained,which provides a suitable theoretical model for the recovery of moisture and heat in the flue gas by the ceramic membrane method.The recovery performance of membrane modules under 9 different working conditions was calculated through the model established in this paper.Comparing the experimental results,it is found that the calculation error of the outlet flue gas temperature and the outlet water temperature is within±0.06%,and the errors of the condensation rate of water vapor and the permeation rate of condensed water are also within±10%.Therefore,it can be considered that the condensation permeation model proposed in this paper can be used for the study of the recovery of waste heat and moisture in the flue gas by macroporous ceramic membrane.In addition,the influence of the inlet parameters and the structural parameters of the membrane module on the condensation rate of water vapor and the permeation rate of condensed water was studied through this model.