Design and Analysis of a Novel Freeze Desalination System for Treatment of Oil and Gas Produced Water

Abstract

Freeze desalination is an alternative technology that has received a lot of attention due to several advantages. Among these, the lower energy consumption and low operation temperature are the most important ones. The operation and maintenance can also be considered simple in comparison to conventional technologies such as membrane-based ones, multistage flash, and Multi-effect distillation. However, the big scale implementation is the main concern for Freeze desalination due to the difficulty to operate it continuously. This study proposes a plant flow process that can operate continuously. Industrial components and actual efficiencies are considered in the development of this process. Moreover, this research is the first to study actual produced water compositions. To do that, a combination of engineering platforms is utilized, ASPEN Plus and OLI Chemical Wizard. Two different plants are proposed: a single-stage system and a two-stage system. Both systems are characterized for achieving temperatures lower than -20 ° by using a direct contact cooling liquid. The influence of different operation parameters is investigated. The results are presented in terms of pure water production, energy consumption, and a thermo-economic study that involves the operation and infrastructure costs. Water recovery ratios ranging from 0.67 to 0.87 were achieved depending on the brine composition. Similarly, the LCOW (Levelized cost of water) was found to be between 0.31 to 0.69 $/barrel of input brine.