Optimization of a single-effect evaporation system to effectively utilize thermal energy

Abstract

Wastewater treatment facilities at Emirates Gold in Dubai seek to improve the steam economy of the existing single-effect with recirculation and vapor-compression evaporation process. Maximizing steam economy is important as it impacts treatment costs. There are two main approaches for improving steam economy in evaporators. One is to use a multiple-effect evaporator; the other is to use a mechanical vapor recompression. Multiple-effect evaporators were rejected because of higher capital and power cost. One of the suggestions that were made towards improving the steam economy was to recover heat from the steam condensate. A modified process flow diagram was proposed and investigated. The modified process was simulated using SuperPro Designer and Hysys with complete material and energy balance computation. The modified process increased the total water evaporation capacity and gained 40% better steam economy of the process. Another advantage was an increase in the amount of water reused, which is both economical and environmentally friendly. © 2008 American Institute of Chemical Engineers Environ Prog, 2009