Waste Heat Recovery Utilization for Thermal-Based Water Desalination to Improve Energy Efficiency at Oil and Gas Operations

Abstract

Abstract The abundance of waste heat generated from gas turbines at oil & gas operations offers a promising avenue for utilizing this thermal energy to desalinate seawater and produce freshwater for various applications using thermal desalination processes. The concept of waste heat recovery is a well-established practice that is currently widely used for the heating of hot oil for purposes such as controlling the quality of the condensate stream. This paper discusses the concept of seawater desalination utilizing waste heat recovery through the thermal desalination process. An assessment of the available waste heat is carried out to evaluate the associated heat capacity for seawater desalination. A block diagram connecting different process units is developed to analyze the integration feasibility of different components involved from feed source (seawater, waste heat) and product (desalinated water or freshwater). Thermal-based desalination technology of multiple effect distillation (MED) is used for the evaluation, and the amount of energy tradeoff is subsequently quantified, based on the scalability of the treated water capacity and potential end use. Process simulation is used to estimate the amount of treated water that can be generated driven by the available waste heat's capacity. Waste heat analysis shows that potentially up to 38 MW of heat can be used for heating the water and used for boiling/distillation to produce the desalinated seawater. This study guides the design strategy and considerations for scaling up the concept of utilizing waste heat recovery from power generation operations for seawater desalination via thermal desalination process. The feasibility of using the freshwater generated either for various uses at oil & gas production facilities or for nearby facilities is also evaluated to achieve energy rationalization and contribute to the decarbonization of oil & gas operations.