METHOD FOR IMPROVING THE PERCENT RECOVERY AND WATER QUALITY IN HIGH TOTAL HARDNESS WATER

摘要

A method is disclosed for improving the percent recovery and water quality in water with high levels of hardness. Embodiments of the method include receiving a produced water composition, partially softening the water composition, and directing the partially softened water composition through at least one reverse osmosis unit. The method may be used to purify and clarify produced water from oil and gas operations for use in boilers or once-through steam generators.

主权项

1. A method of improving the percent recovery in a produced water composition with high levels of hardness, the method comprising:
directing clarified water through at least one membrane module comprising a plurality of membrane elements in series flow, each succeeding membrane element after the first receiving a retentate fraction from the preceding membrane element as feed, wherein the concentration of contaminants in the retentate fraction increases as the fraction cascades to each of the plurality of membrane elements in series; treating the retentate feed fraction to each membrane element in the module to reduce the fouling tendency of each of the membrane elements; and recovering a purified water from the membrane module,wherein the clarified water is produced by a method comprising:
receiving a produced water composition, the produced water composition comprising a mixture of water, oil, and solids; removing oil and solids from the produced water in at least one filter to recover a filtered water composition, wherein the filtered water composition contains particulates that are at most 5 μm in size and wherein the filtered water composition contains less than 5 ppm oil; partially softening the filtered water composition by removing from 30-70% of the hardness contained therein to produce a partially softened water composition; adding an antiscalant to the low turbidity water composition to form the clarified water.