Process Analysis Of Cross-flow Vacuum Membrane Distillation And Characteristics Study Of Membrane Module Scale-up

Rational development and utilization fresh water resources have been always thefocus for people’s attention, especially under the condition of fresh water shortagenowadays.As a novel membrane technology in water treatment field, membrane distillationtechnology has many advantages, which other technologies can not match. In recentyears, membrane distillation research presented explosive growth trend. However,membrane distillation technology has not been large-scale application, and one of themost important reason is flux attenuation in large-scale device.Aiming at flux attenuation two perspectives were taken under deeply analysesed.The first one is the performance of the hollow fiber membrane in the membranemodule, and the second is the performance of the the membrane module in membranedistillation system.A set of automatic control membrane distillation desalination setting wasdesigned and assembled for getting important parameters of membrane distillationprocess. A cross flow membrane distillation model was built to describe the transferprocess of membrane distillation process, based on the characteristics of cross flowmembrane distillation process.An important means for playing its potential of hollow fiber in the membranemodule is designing feed distribution consistent with the membrane modulecharacteristics. CFD techniques was used to simulate the velocity distributions of themembrane module with different feed distributors, then adjusted the feed distributorspaprmeters based on the velocity distributions to optimize the feed distributors.Finally, three optimized distributors which called flat-plate distributor, domelikedistributor and pyramid distributor were obtained. The permeate flux of the membranemodules were enhanced with the optimized distributor fixed on.To find out the reason of operation conditions on feed outlet temperature, watervapor state, permeate flux, energy consumption, temperature polarization coefficientand total mass transfer coefficient, these parameters must be analysed deeply. A seriesof five membrane modules with different characteristic parameters was designedaccording to the characteristics of feed flow in the membrane module. The scale-up experiments were conducted after the modules match with corresponding distributors.It’s find that the optimization of membrane distillation system is an useful method toenhance permeate flux, based on the hollow fibers got full performance.Membrane module#MM4was choosed to conduct water treatment, based onthe analysis of scale-up experiment. Experimental results showed that the treatment ofindustry water by membrane distillation technology was feasible, after the tentativeexperiment for membrane distillation to treat simulation nature gasmining.wastewater, RO concentration and the waste water in hydrometallurgy.