Feasibility Study of Using Waste Heat from Gas Pressure Reducing Stations for Water Desalination

In recent years, recovering waste heat to reduce energy consumption and provide the energy needs has become a promising method to solve the energy crisis. In this study, the waste heat from gas pressure reducing stations is used to produce fresh water using a humidification-dehumidification desalination unit. Using Aspen HYSYS to model the proposed system, the effect of different parameters on the fresh water production rate is evaluated. The results show that optimum saline water and air flow rates are ۰.۱۶۵ kg/s and ۰.۲ kg/s, respectively, for a gas pressure reducing station by a capacity of ۵۰,۰۰۰ standard cubic meters per hour. It is also found that by decreasing the gas inlet pressure from ۱۰۰۰ psi to ۴۰۰ psi, the fresh water production rate is decreases by about ۵۲.۲%. The increase of the fresh water production rate by increasing the capacity of the pressure reducing station from ۱۰,۰۰۰ to ۵۰,۰۰۰ standard cubic meters per hour is about ۶۲%. Furthermore, the fresh production rate at gas pressure reducing station with ۱۰,۰۰۰ SCMH increases ۴.۴% by increasing the saline water temperature entering the humidifier from ۴۰ºC to ۸۰ºC.

Keywords:

Gas pressure reducing station (PRS) , Water desalination , Humidification-dehumidification unit , numerical simulation , ASPEN HYSYS