Continuous-Flow Ultrasonic-Assisted Plasma-Driven Solution Electrolysis Reactors for Crude Oil Degradation in Hypersaline Produced Water with Hydrogen Co-Production

This work evaluates the performance of three configurations (V1, V2, and V3) of novel membraneless continuous-flow ultrasonic-assisted plasma-driven solution electrolysis (PDSE) reactors (CombiSonoPlasma®) operated at near-ambient temperature and pressure, for the single-pass treatment of model hypersaline produced water (HPW) originating from the oil extraction industry, with simultaneous hydrogen co-production. The performance of the reactors was assessed based on (i) the formation of gaseous oil decomposition products (CO, CO2, and CH4) as indicators of crude oil destruction and (ii) hydrogen generation as a valuable energy co-product. The results demonstrate that coupling ultrasonication with PDSE provides a bidirectional synergistic effect: ultrasonication reduces the PDSE electric power demand, while PDSE operation simultaneously decreases the power consumption of the ultrasonic generator. Among the investigated configurations, along with improved oil decomposition, Reactor V2 delivered the most pronounced energy benefits, achieving reductions in electrical power consumption of 33.5% for PDSE and 44.5% for the ultrasonic generator. These findings highlight the potential of continuous-flow ultrasound-assisted PDSE as an energy-efficient process intensification strategy for oilfield HPW treatment combined with hydrogen co-generation.