Study On The Recycling Of Methanol And Acetone By Absorption-adsorption

In order to dissolve the polymer material,a large amount of volatile organic solvent are used in chemical production process,which will cause harm to the environment and human body,so it is necessary for recycling.In this paper,volatile organic gas was from a pharmaceutical factory which contain methanol and acetone with the volume fraction of 4% and 2%,and the treatment process of methanol and acetone with the method of absorption and adsorption was studied.In this paper,the process of absorption and desorption was simulated by Aspen Plus with NRTL equation.The absorption column and desorption column were simulated and optimized,determining the absorption column of the theoretical plate number of 10,the amount of absorbent of 4400 kg/h,and the temperature of the absorbent of 20 ?,and the desorption column of the theoretical plate number of 24,the feed stage of 10,the feed temperature of 75?,and the reflux ratio of 4.4.At the same time the water recycling and heat exchange network was established between the absorption column and the desorption column,which realized the water recycling comprehensive utilization of heat energy.Under the optimum operation parameters,methanol was reached the discharging standard,and most of the acetone was absorbed,with a small amount of acetone unabsorbed to adsorption process.The double effect pressure swing distillation was adopted to recover methanol and acetone,determining the low pressure column of the theoretical plate number of 36,the feed stage of 22,and the reflux ratio of 1.8,and the high pressure column of the theoretical plate number of 36,the feed stage of 13,and the reflux ratio of 2.9.Compared with the traditional pressure distillation,the double effect pressure distillation can save the total energy by 47.78%.Through the study of the activated carbon adsorption process for acetone,which indicates that acetone for monolayer adsorption on activated carbon adsorption.Langmuir model and Freundlich model can well describe the adsorption of acetone process on activated carbon,also suggests that the adsorption of acetone on activated carbon is given priority to with micropore adsorption.The adsorption effect of acetone on activated carbon for different temperature and bed height was studied,and it shows that temperature had little effect on penetrating time within the small range of the change of temperature.Changing the bed height will not change the mass transfer driving force,and it will only make the breakthrough curve parallelling moving around.Aspen Adsorption was used to simulate the adsorption process of acetone gas temperature swing by choosing appropriate mathematical model of adsorption.The adsorption of acetone at different stages and the change of the temperature at the adsorption column was discussed.Finally the purification and recycling of acetone were realised...