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 humidificationdehumidification 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 0.165 kg/s and 0.2 kg/s, respectively, for a gas pressure reducing station by a capacity of 50,000 standard cubic meters per hour. It is also found that by decreasing the gas inlet pressure from 1000 psi to 400 psi, the fresh water production rate is decreases by about 52.2%. The increase of the fresh water production rate by increasing the capacity of the pressure reducing station from 10,000 to 50,000 standard cubic meters per hour is about 62%. Furthermore, the fresh production rate at gas pressure reducing station with 10,000 SCMH increases 4.4% by increasing the saline water temperature entering the humidifier from 40ºC to 80ºC.