Study On Enhanced Absorption Of Methanol Waste Gas By Ultrasonic Atomization Technology

Ultrasound atomization technology has the advantages of small droplet volume,high humidification intensity and uniform particle size distribution,but it has not been applied to the purification of volatile organic compounds（VOCs）.The purpose of this research is to explore the application of ultrasonic atomization technology on the basis of methanol（CH3OH）absorption in ordinary packed tower to enhance CH₃OH absorption.It provides a scientific basis for the application of ultrasonic atomization technology in ordinary packed tower to absorb CH₃OH.With water as absorbent and CH₃OH gas as absorptive substance,the influence of enhanced absorption atomization technology on purification efficiency of CH₃OH waste gas is explored by changing the height of the packed layer and the CH₃OH inlet concentration in the ordinary packed tower by using single factor experiment method and control variable method.Two ways of connecting atomizer nozzles into packed spray tower are changed by adding ultrasonic atomization technology（one is spray at the bottom method,another is spray in the middle method）to judge the optimum purification efficiency through orthogonal experiment.Two different spray methods are also studied comprehensively:1)The relationship between each factor（gas flow rate,liquid flow rate,CH₃OH inlet concentration）and evaluation index（the CH₃OH removal rate,the overall absorption rate）is evaluated.The results show that with the increase of gas flow rate and CH₃OH inlet concentration,the overall absorption rate increases and the CH₃OH removal rate decreases;while the CH₃OH removal rate and the overall absorption rate increase with the increase of liquid flow rate.2)The relationship between the mass transfer performance of each factor（gas flow rate,liquid flow rate,temperature）and the volumetric overall mass transfer coefficient is analyzed.The volumetric overall mass transfer coefficient increases with the increase of gas flow rate,liquid flow rate and temperature.3)The effects of packing layer height and spray density on CH₃OH removal rate are investigated,and the gas-liquid contact areas of different forms are compared.It is concluded that the gas-liquid contact area of the spray at the bottom method is about 26⁴9 times that of the traditional washing method.4)The Fluent14.5 simulation software is used to study the continuous gas phase flow field distribution（velocity flow field and CH₃OH concentration distribution）and dispersed liquid phase concentration distribution（liquid field turbulence intensity）.It is concluded that the gas-liquid contact effect of the spray at the bottom method is better than that of the spray in the middle method.5)With Bettersize 2000 s laser particle size analyzer,testing the particle size distribution of 4 different heights（0cm,15 cm,30cm,45cm）in the tower.The spray performance indexes of the spray at the bottom method（0cm）and the spray in the middle method（30cm）were analyzed.It is concluded that the particle size of the spray at the bottom spray method is smaller than that of the middle method.