Recovery Of Butyl Acetate From Waste Gas

The butyl-acetate gas is harmful to environment and physical health. However,little research has been done on purification and recovery of butyl-acetate at present.In this paper, both of packing tower absorption-stripping desorption and collisionabsorption-stripping desorption were studied for recovery of butyl-acetate from wastegas by simulation. Optimized operating parameters were proposed. An absorptionexperiment was done to verify the simulation. In addition, the research also refers toabsorbent recycling and performance measurements of devices for constructiondesign and improvement.Aspen Plus was adopted for simulation of packing tower absorption-strippingdesorption process to absorb butyl-acetate from waste gas. Factors such as the type ofabsorbent, absorbent flow rate, the inlet waste gas flow rate, temperature of absorbent,number of theoretical stages and feed temperature of stripping tower were taken intoconsideration. The simulation results showed that the recovery of butyl acetate couldreach96.0%and the consumption of streams is0.5kg/h under the optimum absorptionconditions. The optimum absorption conditions were as follows: volume fraction ofmethyl-oleate in absorbent was0.5, flow rate of absorbent was300mL/h, inlet wastegas flow rate was240L/h, the temperature of absorbent was40℃,the number oftheoretical stages in stripping tower was10and the feed temperature in strippingtower was100℃.CFD model and mass transfer model was coupled in this study. Fluent wasadopted for collision absorption-stripping desorption process. Influences such as thecollision velocity of gas, liquid-gas ratio, injection velocity of absorbent and the meandroplet diameter were taken into consideration. The results showed that the recoveryof butyl-acetate could reach92.3%and the consumption of streams was0.03kg/hwhen collision velocity of gas was6m/s, liquid-gas ratio was0.6L/m3, injectionvelocity of absorbent was16m/s and the mean droplet diameter was90μm. Acomparison of the two processes was done, which played an important role inindustrial applications.Mixture solution of methyl-oleate and ethyl-oleate for absorbing butyl-acetatefrom waste gas were studied in a packing tower. Factors such as mass concentration of butyl-acetate, liquid-gas ratio and inlet gas flow rate were taken into considerationfor the recovery of butyl-acetate, the gas absorption coefficient KYa and the height oftransfer unit HOG. Results showed that when mass concentration of butyl-acetate was0.535g/L, liquid-gas ratio was1.25L/m3and inlet waste gas flow rate was4L/min, therecovery of butyl-acetate could reach94.1%.KYa was102.9kmol·m-3·h-1and HOGwas0.37m.Conclusions: Mixture solution of methyl-oleate and ethyl-oleate is suitable forrecovery of butyl-acetate from waste gas. Both of packing tower absorption-strippingdesorption and collision absorption-stripping desorption can get high recovery andlower energy. The best process should base on the local condition.