Produced water softening using high-pH catholyte from brine electrolysis: reducing chemical transportation and environmental footprints
| Autor: | Edward Peltier, Hoil Il Park, Lian-Shin Lin, Paul F. Ziemkiewicz, Harry O. Finklea, Golnoosh Khajouei |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Total organic carbon
Electrolysis Process Chemistry and Technology Inorganic chemistry chemistry.chemical_element 02 engineering and technology 010501 environmental sciences 01 natural sciences Produced water Electrochemical cell law.invention Brine 020401 chemical engineering chemistry law Chlorine 0204 chemical engineering Safety Risk Reliability and Quality Waste Management and Disposal Softening Stoichiometry 0105 earth and related environmental sciences Biotechnology |
| Zdroj: | Journal of Water Process Engineering. 40:101911 |
| ISSN: | 2214-7144 |
| DOI: | 10.1016/j.jwpe.2020.101911 |
| Popis: | This study evaluates the benefits of using brine electrolysis for generating caustic soda (NaOH) and free chlorine for on-site produced water (PWs 1 ) treatment. A two-compartment electrochemical cell was shown to generate NaOH solutions (pH > 12, faradic efficiency 93%) and chlorine (faradic efficiency 32%) from a NaCl brine solution at a current density of 10 mA/cm2. The catholyte was used for softening field-collected PWs. The degree of Mg removal depends mostly on the catholyte/PW mixture pH with pH 11 achieving >90% removal. Ca removal is poor ( 90%). The combined treatment of the catholyte and a reduced quantity of soda ash achieves better or comparable Ca removal compared to the full stoichiometric amounts of soda ash alone. Ba and Sr removal patterns closely follow those of Ca, suggesting co-precipitation of these cations as the primary removal mechanism. Organic removal is negligible during chemical softening; however, activated carbon filtration achieves >90% of total organic carbon (TOC) removal in all PWs. A treatment scheme is proposed for field generation of caustic soda and chlorine from PW. The economic analysis demonstrates the significant cost-effectiveness of the approach compared to purchasing the NaOH. |
| Databáze: | OpenAIRE |
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