Vacuum Regeneration Test Of Anhydrous Alcohol By Molecular Sieve Adsorption

In the industry,adsorption is commonly used in produce anhydrous ethanol,and 3A molecular sieve is selected as an adsorbent.When the molecular sieve has been adsorbed for a certain period of time,it needs to be regenerated for its recycling use.The method of vacuum regeneration for molecular sieve was studied in this paper.In this paper,a three-segment cylindrical adsorption column with diameter of100 mm and height of 1000mm is used,which filled with two kinds of 3 A molecular sieve that are equal filling amount of spherical 4 mm in diameter and cylinder 2.9³.2 mm in diameter.By changing the number of the segments,the loading height of adsorption column is 800 mm,1700 mm and 2700 mm respectively.The single bed adsorption test is used to examine the bed temperature change with time,and the effects of mass velocity and feed temperature,bed height and feed concentration on penetration of time and capacity,and production strength were also analyzed.Then according to the absorption relevant data and process,the double-column process was designed to study on vacuum regeneration.The heat consumed by vacuum regeneration is the adsorption heat stored in the adsorption process,which does not require extra heat.The effects of mass velocity,adsorption time and adsorption temperature on product concentration,quantity of production,and specific yield were investigated.Heat of the N₂ purging,anhydrous ethanol steam purge and vacuum regenerative is calculated respectively.The heat consumption about the thin alcohol distillation again of the above three ways was compared.Through test and calculation results highlight the energy-saving advantages of vacuum regeneration,which provide data and theoretical support for the regeneration way.Through the analysis of test and calculation results,we can get the following conclusions:Adsorption process:The bed temperature first increased and then decreased with adsorption time,as well as the highest point moved with the flow direction.The breakthrough time and penetration capacity increased with the decrease of mass velocity and feeding temperature of the gas,which increased with the increase of the bed height and the concentration of feed.And the production strength increased with the increase of the mass velocity and the concentration of feed,which was contrary to the change trend of the bed height.Regeneration process:During the vacuum regeneration test,the concentration of thin alcohol decreased with the increase of mass velocity,adsorption time and feed temperature.The amount of product increased with the increase of mass velocity,adsorption time and feeding temperature.The amount of thin alcohol increased with the increase of mass velocity and adsorption time,but which has a contrary trend with changes of the feed temperature.The specific yield of thin alcohol increased with the decrease of mass velocity,adsorption time and feeding temperature.When the adsorption time,mass velocity and adsorption temperature is 7 min,0.2246 kg.m^-2.s^-1and 160?respectively,the specific yield of thin alcohol is low to 15.72%.And the specific yield of thin alcohol decreases to 13.80%when the temperature increases to200?.The calculation heat shows that heat consumption per unit product is different which the order from big to small is N₂ purging,anhydrous ethanol vapor purging and vacuum regeneration.And N₂ purging process heat consumption is much higher than the other two ways.After vacuum regeneration,the heat consumed by thin alcohol re distilled is lower than that of anhydrous ethanol regeneration,and equal with that of N₂ purging regeneration.Through the analysis of regeneration test and heat calculation,superheated gases adsorption and regeneration that heat accumulation adsorption combines with vacuum-pumping can reduce the heat loss and thin alcohol.