Techno-economic analysis of tube bundle orientation for high capacity brine recycle MSF desalination plants Original Research Article

As of today, the Multi Stage Flash (MSF) evaporator capacity has reached to 20 MIGD of desalinated water using traditional brine recycle and cross tube bundle configuration. However, on the way of scaling-up evaporator unit production beyond 20 MIGD, there are some technical barriers and economical aspects that need to be considered. This work presents a techno-economic comparison between long tube (LT) and cross tube (CT) bundles of MSF evaporator for a unit production of equal and greater than 20 MIGD. Process calculations showed that the heat transfer surface area of MSF-LT is 25% lower than that of MSF-CT. This is mainly owing to an enhancement in heat transfer process. The pumping power in LT evaporator decreases by 8% due to the lower friction loss. For a large size project of 100 MIGD, the saving in the total capital investment of MSF-LT evaporator is 15% lower than that of MSF-CT. The operating cost is the same. A novel layout of MSF-LT configuration is proposed in which the stages are arranged in triple decks to reduce the footprint up to 51%. The novel configuration enables a significant reduction in the water box size and numbers.