气扫式多效膜蒸馏过程数学模型研究

Study on mathematical model of sweeping gas multiple-effect membrane distillation process

针对传统气扫式膜蒸馏(SGMD)过程能耗高的问题,设计了一种气扫式多效膜蒸馏(SGMEMD)过程.该过程同时具有蒸汽的换热冷凝与料液的预热升温双重作用,从而实现蒸汽潜热的梯级回收利用.根据吹扫气流速、料液循环流量、料液进水温度、料液浓度主要操作参数对气扫式多效膜蒸馏(SGMEMD)过程性能影响的实验研究结果,运用曲线拟合法,分别建立了膜蒸馏通量J和热量回收率η随着以上参数变化的经验公式.在此基础上,建立造水比(GOR)的半经验半理论数学模型.经L9(34)正交试验验证,所建立的经验公式及数学模型均能很好的预测SGMEMD过程的J和GOR.J和GOR计算值与实验值的相对偏差均在±8.0%以内.

A novel sweeping gas multiple-effect membrane distillation process（SGMEMD）was designed based on the high energy consumption of sweeping gas membrane distillation（SGMD）process.The process was set up for the first time with a special latent-heat recovery system where the vapors was condensed and the feed heated up simultaneously.Thus the latent-heat could be recovery gradually and effectively.The empirical formulas of membrane distillation permeate flux Jand heat recovery rateηthat describes sweeping gas multi-effect membrane distillation processes（SGMEMD）were presented using curve fitting method,which was according to results of single factor experiment,that is,the effects of sweeping gas flow velocity,feed circulation volumetric flow,feed temperature and the feed concentration on performance of SGMEMD process were investigated.Based on the empirical formulas,a semi theoretical model of GOR was established.The empirical formulas and semi-theoretical model had a high precision in predicting the Jand GOR of SGMEMD process,which had been validated by L9（34）orthogonal experiment.Compared to results of experiment,the calculated value of Jand GOR relative deviation were within 8.0%.