Experimental Study On The Performance Of Air Humidification Packed Tower

Air humidification and recovery of waste heat is an effective way to reduce emission and improve efficiency of gas boiler.Air humidification packed tower is an important equipment to realize this process.In this paper,aiming at the air humidification process of gas boiler,the performance of air humidification packing tower is studied experimentally,and the influence of liquid distributor,demister and packing on the performance of air humidification packing tower is studied respectively.According to the experimental results,the design method o f packing tower suitable for the air humidification process of gas boiler is summarized.The main contents of this paper are as follows:(1)Study on the pressure drop performance of stepped ring packing.The performance parameters of dry tower pressure drop and wet tower pressure drop were obtained by air-water system experiment.The results show that the packing pressure drop increases with the increase of gas kinetic energy factor in the range of experimental conditions,and the two changes linearly;under the condition of wet tower,the packing pressure drop increases with the increase of gas kinetic energy factor at the same spray density;with the same kinetic energy factor,the packing pressure drop increases with the increase of spray density.According to the experimental data,the empirical correlation of packing pressure drop is obtained.(2)Experimental study on heat and mass transfer performance of air humidification packed tower.In view of the inlet air condition of gas boiler with 1 t evaporation capacity,the effects of operation parameters(water air ratio,inlet water temperature),packing height,environmental parameters(inlet air temperature,intake air moisture content)on the performance of air humidification packing tower were experimentally studied,and the effects of operation parameters and environmental parameters on the height of packing mass transfer unit were analyzed.The results show that the height of mass transfer unit decreases with the increase of inlet water temperature and water gas mass ratio.At the same inlet temperature,the exhaust moisture content and exhaust temperature increase with the increase of water gas mass ratio and inlet temperature.At the same water gas ratio,the height of mass transfer unit decreases with the decrease of packing height,and the moisture content of exhaust gas and outlet air temperature increase with the increase of packing height.According to the experimental data,the empirical correlation of the height of the mass transfer unit was obtained.(3)Study on the performance of distributor and demister.The liquid distribution performance of two types of liquid distributors was studied separately,The nonuniformity of the nozzle distributor in radial and circumferential direction,the wall flow under different spray density,and the nonuniformity of the main pipe and branch pipe of the discharge distributor were evaluated.The effects of the two distributors on the performance of the air humidification packed tower were compared;The pressure drop and performance of two types of demister were compared.The results show that the circ umferential and radial nonuniformity of the spray nozzle M_F>0.17,and the liquid distribution performance is poor.The Pipelining distributor's nonuniformity M_F<0.05,and the liquid distribution performance is better.Both of them have the same effect on the humidification performance of air humidification packing tower.The pressure drop of the wire mesh demister increases with the increase of the kinetic energy factor of the gas phase.The pressure drop of 200 mm thick wire mesh demister is 50-100 PA larger than that of 100 mm thick wire mesh demister.The former has better demisting performance in the experimental range,while the latter only has better demisting performance under high spray density.The pressure drop of baffle demister changes with t he kinetic energy factor of gas phase,which is kept within 5 Pa basically,but the demister capacity is basically lost under the experimental thickness.(4)Design method summary of air humidification packed tower.Combined with the characteristics of the air humidification process of the gas boiler,the experimental results of the packed tower and its internal components,and the design method of the packed tower.,the design method of packing tower suitable for air humidification is analyzed and summarized.O n this basis,the design of the air humidification packing tower with the evaporation capacity of 1t is completed.