Use of Ambersorb(R) carbonaceous adsorbent for removal of BTEX compounds from oil-field produced water

The removal of high concentrations of BTEX compounds (benzene, toluene, ethylbenzene and xylenes) from oil-field produced waters using a carbonaceous adsorbent was successfully demonstrated in the field. The carbonaceous adsorbent was much more effective in removing BTEX compounds from produced water than activated carbon or modified clays. The primary objectives of the field studies were to evaluate the efficiency of oil removal processes to protect the adsorbent from fouling, to determine the BTEX removal efficiency of a carbonaceous adsorbent at a high flow rate loading, and to demonstrate regeneration of the adsorbent. Adsorbent fouling with oil was mitigated by mechanical coalescing for beavier crude and emission-breaking for lighter crude. Adsorbent extenders and filters did not control fouling in the presence of exceedingly emulsified crude oil. Carbonaceous adsorbent reduced BTEX compounds levels from the 25-130 mg/l range to less than 1 mg/l treating approximately 500 bed volumes of produced water per cycle. Regeneration of the adsorbent using low pressure stream or solvents was successfully achieved with regeneration efficiencies exceeding 95 percent.