Produced Water Treatment of Desalting Unit using Reverse Osmosis Membrane Separation Process

Desalting (dehydration) is the first step in crude oil refining process to remove water, inorganic salts, suspended solids, and water-soluble trace metals that may cause problems to downstream equipments such as corrosion, plugging, fouling, and catalyst poisoning. Reviews of literature conclude that large volume of water is needed for desalting process, and it will surely produce larger volume of water as an effluent. This effluent is then sent to Effluent Treatment System (ETS) prior being discharged to the sea. By looking at the possibility of cost reduction in treating this effluent at ETS, and reduction in the use of fresh water to be injected into the desalting unit, a new treatment system based on adsorption and reverse osmosis membrane is proposed in situ so that the treated water could be recycled into the desalting unit for its process. Desalter’s produced water from Petronas (Melaka) Refinery Sdn. Bhd. At PSR-1 plant area was treated via AFC99 tubular thin film composite polyamide Reverse Osmosis (RO) membrane. The effect of operating conditions (transmembrane pressure, feed concentration, and feed pH) towards permeate flux and percentage salts rejection were studied to get the optimum removal of salts and impurities from the produced water. The experimental results showed that AFC99 membrane removed 100% of TSS and salinity, more than 98% of TDS, more than 97% of salts ions, and more than 95% of COD. This work shows that the RO membrane was feasible and desirable to be used for optimum salts and contaminants removal from produced water of desalting unit. Besides, the treated water (permeate) fulfils the watering standards and can be used for recycling.