Energy Analysis of Methane-Hydrate-Based Produced Water Desalination

Managing produced water (PW) is one of the significant environmental issues pertaining to the energy industry. The PW needs to be treated to meet environmental regulations and can be reused for irrigation and various industrial uses. Currently, reverse osmosis and thermal distillation are the extensively used techniques to remove dissolved salts. However, these techniques are energy-intensive, and there is a search for a low energy desalination technique. Hydrate-based desalination is one of the promising desalination techniques. Detailed energy analysis of the hydrate-based produced water desalination will give the total energy required and efficiency of the process, which is crucial for commercialization. In this study, the process flow sheet of hydrate-based produced water desalination is developed, and a detailed energy analysis is performed. A base case with a 40% water recovery rate from methane and 10 wt % NaCl feed produced water is simulated. The impact of hydrate former recycling, water recovery rate, and salt content in the feed produced water on the specific energy consumed for the process is determined. The energy analysis highlights that external refrigeration is the major contributor to the process's total energy consumption. Therefore, to lower the total energy consumption, a suitable hydrate former that can operate at higher temperatures needs to be identified.

Automated summary

Managing produced water is a significant environmental issue in the energy industry, with reverse osmosis and thermal distillation being commonly used techniques. Hydrate-based desalination shows promise as a low energy option, with external refrigeration identified as a major contributor to energy consumption.