Development of Advanced Compact Energy Recovery Pumping System for Shipboard Seawater Reverse Osmosis Desalination

The proposed advanced, compact, lightweight turbine-pump (ACLTP) assembly takes advantage of the available pressure in the overboard RO seawater stream via hydraulic Turbine expansion which provides additional boost and pressurization up to the target 1,200 psid at the RO module. The ACLTP boost is added to the inboard seawater stream being discharged from the low pressure electric motor driven (main) pump. By boosting the main pump discharge stream, the main pump is not required to develop as much head and pressure as it would if it developed the required 1,200 psid on its own. This reduces the amount of electrical energy the main pump motor will require while providing the target differential pressure into the RO module. Energy savings, depending on the exact flow rates and RO membrane efficiency, initially are indicated to be in the range of 38 percent to 50 percent. The ACLTP design concept can be adapted to systems with a wide range of flow rates. Thus, “frame sizes” can be developed for a broad range of RO capacity requirements.