An Experimental Study On Pervaporation Membrane And Membrane Module In Alcohol Purification

Pervaporation is a new technology of membrane separation for the separation of liquid mixtures, it is a process that uses liquid mixtures' components through compact membrane in different of solution and diffusion velocity under the impulse of component's stream partial pressure, its merit is an alternative for the separation of liquid mixtures, such as azeotropic and closing-boiling mixtures, which are difficult or impossible to separate by conventional methods, it's a cleaning and saving energy technology that accords with sustainable development.Alcohol can be used in many departments of the national economy. It is not only an enormous commodity in market and important industrial material, but also an important regenerated energy. Distillation is one of conventional alcohol purification methods, its power is heat energy, its disadvantages are more energy consumption, great installation cost and poor economic performance.Pervaporation purify alcohol, put up visible advantage on technology and economy. At present, there were over 100 sets of pervaporation equipments in commercial run in the world, but flat-plate membrane module has concentration and temperature polarization, so this paper brings forward vortex generator in flat-plate membrane module, and studies pervaporation membrane's performance and vortex generator in flat-plate membrane module's performance.In the experiments, pervaporation membrane's swelling performance in different alcohol concentration has been researched, the membrane absorb water priority, It can be used in alcohol purification in high concentration, but its degree of membrane's swelling is small, membrane's selectivity is low.In the study of pervaporation membrane's performance, the influencing factors of feed concentration, operating temperature, downstream pressure and feed speed rate have been researched, and this paper generalizes pervaporation membrane's character of mass transfer. membrane's general effect is better in low feed concentration, high operating temperature, low downstream pressure and high feed speed rate.According to membrane's dissolution- diffusion principle, in whole pervaporation process dissolution is a controlling factor in high alcohol concentration. The experiential relationship formula of membrane's permeation flux can forecast osmotic capacity effectively at relative error less than 5%.For vortex generator in flat-plate membrane module in the paper, the paper researched membrane module's advantage from performance of membrane macro-graphicly, and as compared with conventional flat-plate membrane module, vortex generator increase membrane module's effectiveness, and obtain the same effectiveness with conventional flat-plate membrane module in low feed speed rate, vortex generator reduce concentration and temperature polarization.Designed the pervaporation process has been calculated for vortex generator in flat-plate membrane module, the result shows 0.4538 sq.m. membrane area from 94.94wt% feed concentration to lkg/h 99.7wt% absolute alcohol in 70°C,45L/h and 1300Pa.