Unlocking High-Salinity Desalination with Cascading Osmotically Mediated Reverse Osmosis: Energy and Operating Pressure Analysis

• DOI: 10.1021/acs.est.7b05774
• Publication Date: 2018-01-23T00:12:06Z
• Authors: Xi Chen; Ngai Yin Yip
• Keywords: Energy Recovery; Osmotic power; Geothermal desalination; Reverse osmosis plant; Pressure-retarded osmosis; Osmosis; Bar (unit)

Current practice of using thermally driven methods to treat hypersaline brines is highly energy-intensive and costly. While conventional reverse osmosis (RO) the most efficient desalination technique, it confined purifying seawater lower salinity sources. Hydraulic pressure restrictions elevated energy demand render RO unsuitable for high-salinity streams. Here, we propose an innovative cascading osmotically mediated (COMRO) technology overcome limitations RO. The innovation utilizes novel design bilateral countercurrent stages depress hydraulic needed by lessening osmotic difference across membrane, simultaneously achieve savings. Instead 137 bar required desalinate 70 000 ppm TDS feed, highest operating in COMRO only 68.3 (−50%). Furthermore, up ≈17% saving attained (3.16 kWh/m3, compared 3.79 kWh/m3 with RO). When employed boost recovery 70% from typical 35–50%, savings ≈33% achieved (2.11 3.16 Again, can operate at a moderate 80 (25% than 113 This study highlights encouraging potential energy-efficient access unprecedented high rates pressures, thus extending capabilities membrane-based technologies desalination.