P. Sharan, R. Santosh, A. Findikoglu
Los Alamos National Laboratory,
United States
Keywords: produced water, supercritical water desalination and oxidation
Summary:
The modern energy-economy is increasingly causing the production of highly saline brines, including from produced water or extraction of critical minerals like Lithium. Emerging technologies like supercritical water desalination can concentrate and selectively extract minerals from these water sources, but under supercritical conditions, little is understood about mixed salt interactions, organic degradation with additives, costs of these processes, or hybrid systems that produce CO2 or H2. The present study evaluated, modeled, and experimentally studied an integrated supercritical water desalination and oxidation (SCWDO) process for real-produced water samples for energy and desalination applications. The complex interactions between the various anions and cations in produced water were extensively evaluated as a function of feed temperature. The measured heat liberated during the oxidation of organics was shown to enhance the energy efficiency of the overall process, thereby significantly reducing treatment costs. The produced water samples with salt concentration ranging from 10,000 mg/l to 260,000 mg/l were treated to generate a potable quality distillate. Techno-economic analysis showed that treatment cost for SCWDO could be reduced up to 60% compared to traditional deep well reinjection and could achieve net negative CO2 emission (due to flare gas mitigation). Additionally, hydrogen production from produced water is proposed in this study, which would reduce the dependence on freshwater sources for hydrogen. Utilizing marginalized water feedstocks could prove essential in human society’s growing water, energy, and environmental crises.