Feasibility of sweeping gas membrane distillation on concentrating triethylene glycol from waste streams

High treatment efficiency and low energy consumption are desired factors for any process intensification from an industrial prospective. It can be noted to be the same for membrane-based processes for treating triethylene glycol (TEG) wastewater, which is generated from dehydration step in natural gas processing. In-this study, sweeping gas membrane distillation (SGMD) was applied to investigate both the potential of process intensification of triethylene glycol (TEG) from binary solutions (water and TEG) and from real wastewater. A hydrophobic hollow fiber membrane module (0.255 m(2)) was operated with both synthetic and real TEG wastewater. The feasibility of SGMD for concentrating TEG was done by evaluating various key factors which where; optimizing operating condition like feed temperature, feed flow rate, and sweeping gas flow rate vs permeate flux, energy consumption evaluation and fouling analysis. Experimental results showed that SGMD had the ability to concentrate TEG in real wastewater till 98%. During concentrating TEG from 9.69 to 50%, the permeate flux was in the range from 1.6 to 2.4 kg/m(2) h with the ratio of energy of 1.4 kWh/kg. In regard to fouling, estimations were made for total resistance, membrane resistance, boundary layer resistance and fouling resistance. Fouling contributed 69.2, 7.6, and 23.2% respectively, whereas irreversible resistance accounted for 2% of the total fouling. The results, indicate that bench scale SGMD was able to concentrate TEG up to 98% and potential for pilot scale studies are in need for further scale up. (C) 2016 Elsevier B.V. All rights reserved.