A stepwise model of direct contact membrane distillation for application to large-scale systems: Experimental results and model predictions

• A simplified membrane distillation coefficient calculation method is validated. • A stepwise modeling approach is shown to accurately model large-scale DCMD membrane modules. • A new spacer modeling method accounts for woven spacers with complex geometries. • Distribution of water flux, temperature and concentration along the membrane are modeled.

Fig. 14. Experimental results and model predictions of water flux for one, two, and three membrane modules in-series. Flow mode was co-current at a flow rate of 1.5 LPM, feed inlet temperature was 65 °C, distillate inlet temperature was 45 °C, and feed concentration was 100 g/L NaCl. A stepwise model of mass and heat transfer in DCMD was developed and validated with experimental results using a GE QM022 flat sheet PTFE membrane. Experimental data combined with model calculations indicated that the MDC for the QM022 membrane could be accurately modeled as a constant value over typical DCMD operating conditions, Fig. 15. Distribution of (a) feed and distillate temperatures, (b) water flux, and (c) feed concentration along the length of the membrane.