Recycle of Methanol From Wastewater in the Methanol to Olefin Process By Pervaporation

Polymeric membranes have been used for organic compounds dehydration, removal of organic compounds from water and organic mixtures separation by pervaporation. The application of methanol recycle from water on the laboratory scale by pervaporation through commercial polymeric composite membranes was introduced. In the methanol to olefin (MTO) process, large number of wastewater rich in high concentration of methanol was produced, the methanol concentration in MTO wastewater was from 0.5wt.% to 10.0 wt.%. In this work, methanol removal from methanol/water mixtures with two types of commercial membranes was experimented. The effect of water temperature, methanol concentration and feed flow on the permeation fluxes and separation factors of membranes was investigated. The results indicated that the permeation fluxes were both increased with the rise of temperature and methanol concentration, and the separation factor of membrane PDMS-A was changed notably, membrane PDMS-B, however, was less changed, and the influence of feed flow was little. The membrane had a 914.6 g/m² h flux and an methanol/water separation factor of 5.6 for a 5.8 wt.% methanol/water feed using membrane PDMS-A at 343K, the flux and separation factor were 1887.2 g/m²h and 4.8, respectively, using membrane PDMS-B at the same temperature.

Keywords: Pervaporation; Polydimethylsioxane; Methanol; Membrane; Water