oa Techno-economic Analysis Of High Performance Novel Hybrid Msf-fo Desalination Plant

The role of using Forward Osmosis (FO) or Nano filtration (NF) as a pre-treated method to the existing MSF desalination plants is to reduce divalent ions which cause hard scale deposition at elevated temperature. The separation of divalent ion enables to increase the desalination process temperature greater than 110 0C which consequently increases the plant performance, increase the productivity as well as reduce the chemical consumption. Integration of NF system to existing MSF desalination plant and treatment of only 30% of make-up enable to increase the TBT up to 130°C, the production can be increased to 20%. The cost analysis showed the unit product cost is 5.4% higher than that conventional MSF (at 110°C) due to the additional capital cost of NF system. Integrating NF system to novel configuration (NF-MSF-DM) desalination plant at the TBT = 130°C, the gain output ratio could be as high as 16, i.e. double the convention MSF-BR. The new NF-MSFDM configuration significantly reduces the unit's input thermal energy to suit the use of (the relatively expensive) solar energy as a desalination plant driver. Integrating FO to existing MSF and use the brine of the last stage as a draw solution at a recovery ratio of 35 % reduces the Ca+ ions in the seawater feed by 20 % which enables to increase the TBT up to 130 0C safely. The simulation results show at TBT = 130 0C, the production of the existing MSF plant increases by 20 %. The OPEX analysis showed an amount of 2.3 M$/Year of chemical cost can be saved if the FO deployed to the existing MSF plant in Qatar. The trade off point between the additional CAPEX of FO membrane system and saving in OPEX will be considered under different operating condition in the present work.