Simulation of a Thermal Desalination System

EasyChair Preprint 7274

Abstract

Desalination technology offers the sustainable solution of providing freshwater supply to the water-scarce coastal areas such as the region from Karachi and Gwadar cities situated in Pakistan. Reverse osmosis (RO) desalination is an energy-efficient technology. However, recent advances such as the integration of adsorption/absorption vapor compression systems and the development of new antiscalants for the multi-effect desalination (MED) technology have made it a competitive choice. The MED unit's current top brine temperature (TBT) is 65 °C (because of salt precipitation in the evaporators), for which 8 – 10 falling film evaporators can be installed. But with the progress in antiscalants, the TBT can be stretched to 85 °C that reflects the incorporation of more evaporators and hence more freshwater productivity. For this purpose, a mathematical model of the MED unit is developed in Engineering Equation Solver (EES), and the performance of the MED unit is assessed at higher TBT. The mathematical model is validated with the empirical model available in the literature and with the commercial desalination plant located in Qatar. It is found that the performance ratio of the MED unit with TBT of 80 °C is 22.8% higher than that of 65 °C TBT. Furthermore, the specific heat transfer area is 18% higher, and the cooling water requirement is 76% lesser for the MED unit with TBT = 80 °C as compared to the MED unit with TBT = 65 °C.

Keyphrases: Desalination, Falling Film Evaporator, Multi-Effect Desalination, Performance Ratio, Top brine temperature, energy efficiency

@booklet{EasyChair:7274,
  author    = {Hammad Tahir and Muhammad Sameer Ali Khan and Mohammad Mowahhad Ullah and Muhammad Ali},
  title     = {Simulation of a Thermal Desalination System},
  howpublished = {EasyChair Preprint 7274},
  year      = {EasyChair, 2021}}