Design and development of a small multistage flash desalination system using Aspen HYSYS

Fresh water demands are increasing day by day because of growing population, industrialization, and increased living standards. Desalination technology has become a significant solution of fresh drinking water for many parts of the world. Lack of fresh water resources in dry environments has encouraged the establishment of desalination processes and developed technology to compensate for water scarcity. The MSF (multistage flash) desalination technique has received wide spread acceptance due to low temperature heat source (waste heat/inexpensive energy), simple construction high process reliability and simple maintenance. MSF typically has the highest water production cost among available desalination technologies, which can be reduced with using solar energy/cogeneration. Since Abu Dhabi is in the solar belt region and is blessed with huge solar energy, MSF desalination can be powered by solar power in addition to industrial waste/fossil fuel energy, which will significantly reduce the cost as well as carbon, footprint. In this research, multistage flash desalination is modelled using ASPEN HYSYS package V8. We have designed each components of the system, mostly heating source, vacuum/flash chambers, heat exchangers and developed the whole system. Some parametric study, i.e. feed rate, top brine temperature, heat input, pressure, productivity etc. of multistage flash desalination system has been conducted in this research. Two case studies have been conducted and found a relation between feed flow rate and water production rate as well as chamber pressure with vapor formation. This design will help to build the pilot plant, do experimental test and validate the model.