Distillation performance in a novel minichannel membrane distillation device

To lessen the polarization effect in membrane distillation and increase the permeation flux, a minichannel membrane distillation device (MMDD) was developed. The influence of the gap size, feed temperature, flow rate, and flow type on the permeation flux during membrane distillation was investigated. The permeation flux was enhanced by reducing the gap size, increasing the feed temperature and feed flow rate, and employing coun-tercurrent flow. Based on the heat and mass transfer model of the membrane distillation process, a mathematical model for predicting in the influence of the membrane parameters on the temperature polarization coefficient and thermal efficiency in the MMDD was constructed. The theoretical values were verified to be in good agreement with the experimental data. Using the MMDD, the permeation flux and the temperature polarization coefficient increased by 160 % and 35 %, compared with those of conventional membrane distillation devices, respectively. Thus, it is proved that the proposed MMDD effectively eliminates the polarization effect, boosts the thermal efficiency, and improves the efficacy of membrane distillation performance.