Refinery processed water treatment via the low energy Direct Contact Membrane Distillation (DCMD)

The amount of refinery water discharged to the environment from oil industry has remarkably increased. Research has been focusing on the use of membrane technology for the refinery processed water treatment, particularly membrane distillation (MD), which is an emerging technology that has been highly marked by its low-energy requirement and high desalination efficiency. An anti-oil-fouling membrane is vital for a successful oil-water separation by MD. Underwater-oleophobic membrane is based on the asymmetric surface wettability, whereas the omniphobic membrane is attributed to the surface structure that is characterized by having a very large contact angle for all liquids. In the present study, high fidelity numerical simulation of direct contact MD (DCMD) was conducted using non-isothermal CFD validated model to assess the role of the anti-oil-fouling membrane properties on the performance of the DCMD. Results showed the compromising effect of membrane porosity to 45% reduces the mass flux and thermal efficiency respectively by 68% and 40%, and reduction of pore size to the half can cause a reduction by 50.6% in mass flux and 24.18% in thermal efficiency compared to the baseline. Meanwhile, the omniphobic slippage effect led to a noticeable gain of 16% in DCMD mass flux with slight gain in thermal efficiency. This can maximize mass flux and thermal efficiency to be as much as 50.3 kg/m ² -h and 69%, respectively.