Second law analysis of multieffect and multistage flash desalination plants

M. Sh Al-Ahmad, M. A. Darwish

Research output: Contribution to journalConference article


Although the first law of thermodynamics indicates the overall performance of the desalting plants, it does not show the actual losses from each component (i.e. process) of these plants. These can be revealed by an analysis where the second law of thermodynamics is applied to the multieffect, once through multistage flash, and recirculation multistage flash desalting plants. The exergy losses from the different processes in each plant are determined for each stage or effect. The processes of major exergy losses are the vapor condensation (condenser exergy loss), vapor flashing (flashing exergy loss) and feed heating in the brine heater (heating exergy loss). Finally a comparison between the exergy losses is conducted for the three types of plants and for the same gain ratio. The major specific exergy losses are compared for the three plants. It is found that the multieffect plant is the least exergy wasting plant.

Original languageEnglish
Number of pages1
JournalInstitution of Chemical Engineers Symposium Series
Issue number125
Publication statusPublished - 1 Jan 1991
EventProceedings of the Twelfth International Symposium on Desalination and Water Re-use - Malta, Malta
Duration: 15 Apr 199118 Apr 1991


ASJC Scopus subject areas

  • Chemical Engineering(all)

Cite this