Modeling and optimization of a commercial permeate gap spiral wound membrane distillation module for seawater desalination

In this paper, a commercial spiral wound PGMD module was modeled and optimized for seawater desalination using Response Surface Methodology (RSM). Permeate flux (P-flux) and specific thermal energy consumption (STEC) were the main performance parameters to optimize, while evaporator inlet temperature (T-evap), condenser inlet temperature (T-cond) and feed flow rate (F) were the three operating parameters chosen. Analysis of variance (ANOVA) was used to evaluate statistically the response surface models. According to the study, T-evap, had the strongest effect on P-flux and STEC, increasing the former and decreasing the latter, F increased both responses, and T-cond had a weak effect on P-flux and practically none on STEC. The models were validated with further experimental data and a good correlation between experimental and predicted values of the responses was obtained for P-flux and STEC respectively. An optimization was performed to determine the operating conditions that produce a maximum value of P-flux and a minimum value of STEC simultaneously. The result of the multiple responses optimization using desirability function was a maximum Pflux of 2.661/h.m(2) and a minimum STEC of 255.8 kWh/m(3).