Performance of sodium a zeolite membrane for water-ethanol separation in pervaporation system

Abstract

In this study, NaA zeolite membranes were mainly synthesized using silica and alumina as precursors via microwave, autoclave (or conventional heating),and electrophoretic techniques. The influences of composition, seeding time, synthesized time, and temperature were investigated. The results showed the successfully synthesized NaA zeolite membranes on the tubular alumina support using 2 min seeding time at 333-363K synthesized temperature for 20 min to 20 h, depending on the technique used. The performance of NaA zeolite membranes was investigated using pervaporation system for water-ethanol separation, and the results 10,000, indicating a good performance of the synthesized membranes. However, when the thickness of NaA zeolite membrane was decreased, the total water flux of the system increased to higher than 2.0 kg/m2/h with the separation factor higher than 10,000. Moreover, the synthesized NaA zeolite membranes also showed a good stability in the pervaporation system. The techno-economic analysis of the pervaporation system for ethanol production was studied to compare with a conventional process using PRO II simulation program by using 50:50 of ethanol to water ratio with 1000 kg/h as a feed stream. From the techno-economic results using the hybrid system (a commercial distillation followed by the pervaporation system), it was found more economically attractive than the azeotropic distillation system (a commercial distillation followed by the practical azeotropic distillation) for producing ethanol with purity around 99.5% wt at around 500 kg/h. It not only saved significant energy required for producing 99.5 %wt of ethanol, but also was an environmentally friendly process.