Tri-hybrid NF/RO/MED Desalination System has been developed in collaboration with Saline Water Desalination Research Institute (SWDRI) / Saline Water Conversion Corporation of Saudi Arabia, Water Reuse Promotion Center (WRPC) of Japan and Sasakura Engineering Co., Ltd.
A fully integrated NF/RO/MED hybrid pilot plant was built and commissioned at the SWDRI premises in Jubail in April, 2008. The patents for this technology are jointly owned by SWDRI, WRPC and Sasakura Engineering Co., Ltd.
The main features of the Tri-hybrid System are as follows:
- NF pretreatment performance for the removal of scale components and reduction of TDS under steady operation. This feature contributes to a high recovery rate for the RO operation as well as to enable high temperature operation of MED without scale formation.
- Operation of SWRO at high recovery rate of 50% and reuse of the reject RO brine as MED feed. This feature enables the reduction of seawater intake required by about 50%.
- MED operation at high temperatures of up to 125°C, thus directly contributing to a significant increase of overall heat transfer efficiency. Therefore, a significant reduction is achieved for both CAPEX and OPEX, considering a Performance Ratio (PR) of 20 attained.
- Newly developed Scale Saturation Index (SSI) on-line analyzer to protect against scale formation when operating the plant under various conditions including high temperature and high TDS conditions.
- Selected plant construction materials are validated via means of corrosion tests under harsh operating conditions (i.e. high temperature and high TDS operation).
- Consistent Plant Performance results since commissioning of Pilot Plant; this technology is ripe for commercialization.
Figure-1: Typical flow schematic for Tri-hybrid NF/RO/MED Desalination system
Figure-2: Conceptual design.