Islam Md Rashedul, Lin Bosong, Yu Yue, Chen Chau-Chyun, Malmali Mahdi
Department of Chemical Engineering, Texas Tech University, Lubbock, TX 79409-3121, USA.
Membranes (Basel). 2023 Feb 24;13(3):273. doi: 10.3390/membranes13030273.
This paper presents a comparative performance study of single-stage desalination processes with major configurations of membrane distillation (MD) modules. MD modules covered in this study are (a) direct contact MD (DCMD), (b) vacuum MD (VMD), (c) sweeping gas MD (SGMD), and (d) air gap MD (AGMD). MD-based desalination processes are simulated with rigorous theoretical MD models supported by molecular thermodynamic property models for the accurate calculation of performance metrics. The performance metrics considered in MD systems are permeate flux and energy efficiency, i.e., gained output ratio (GOR). A general criterion is established to determine the critical length of these four MDs (at fixed width) for the feasible operation of desalination in a wide range of feed salinities. The length of DCMD and VMD is restricted by the feed salinity and permeate flux, respectively, while relatively large AGMD and SGMD are allowed. The sensitivity of GOR flux with respect to permeate conditions is investigated for different MD configurations. AGMD outperforms other configurations in terms of energy efficiency, while VMD reveals the highest permeate production. With larger MD modules, utilization of thermal energy supplied by the hot feed for evaporation is in the order of VMD > AGMD > SGMD > DCMD. Simulation results highlight that energy efficiency of the overall desalination process relies on the efficient recovery of spent for evaporation, suggesting potential improvement in energy efficiency for VMD-based desalination.
本文介绍了具有膜蒸馏（MD）模块主要配置的单级脱盐工艺的比较性能研究。本研究涵盖的MD模块有：（a）直接接触式膜蒸馏（DCMD），（b）真空膜蒸馏（VMD），（c）吹扫气膜蒸馏（SGMD），以及（d）气隙膜蒸馏（AGMD）。基于MD的脱盐工艺采用严格的理论MD模型进行模拟，并辅以分子热力学性质模型，以准确计算性能指标。MD系统中考虑的性能指标是渗透通量和能量效率，即产出比（GOR）。建立了一个通用标准，以确定在各种进料盐度下进行可行脱盐操作时这四种MD（在固定宽度下）的临界长度。DCMD和VMD的长度分别受进料盐度和渗透通量的限制，而AGMD和SGMD则允许相对较大的长度。针对不同的MD配置，研究了GOR通量对渗透条件的敏感性。在能量效率方面，AGMD优于其他配置，而VMD的渗透产量最高。对于较大的MD模块，热进料提供的热能用于蒸发的利用率顺序为VMD>AGMD>SGMD>DCMD。模拟结果表明，整个脱盐过程的能量效率依赖于蒸发余热的有效回收，这表明基于VMD的脱盐在能量效率方面有潜在的提升。
