Coal seam gas produced water treatment by ultrafiltration, reverse osmosis and multi-effect distillation: a pilot study

摘要

This study evaluates the technical feasibility of a pilot treatment train of ultrafiltration, reverse osmosis (RO), and multi-effect distillation (MED) for coal seam gas (CSG) produced water treatment. A total of 12,000 L of CSG produced water was processed from the Gloucester Basin in New South Wales (Australia). The results demonstrate the technical feasibility to obtain an overall clean water recovery of 95% and a final brine containing mostly sodium bicarbonate up to of 48 g/L. Stable operations of the pilot RO and MED systems at 76% and 80% recovery, respectively, were achieved. The results show that anti-scalant addition could effectively prevent scaling during MED operation. Mass balance analysis and analytical measurement suggest that precipitation of calcium, magnesium and silica might have occurred. Indeed, mineral deposition on the sight glass of the MED evaporative chamber became visible after 3 days of continuous operation. However, no evidence of mineral precipitation or scaling could be observed on the evaporative tubes of the MED system. In addition, the mineral deposition on the sight glass was completed removed by chemical cleaning at the end of the pilot evaluation program. The obtained RO permeate and MED distillate were of high quality and could be blended with UF filtrated CSG produced water for irrigation to reduce the treatment demand.