Produced water (PW) generated from hydraulic fracturing operations contains varying amounts of crude oil, sand and dissolved ions, and is typically characterized as hyper-brine. It is often untreatable by existing desalination technologies. This study presents using the directional solvent extraction (DSE) technique to desalinate multiphasic, synthetic produced waters (SPW) using diisopropylamine (DIPA) as the extraction solvent and a ferrate pretreatment method. DSE with ferrate pretreatment achieved an average solvent efficiency of 0.25, 0.13 and 0.03 mL water/g solvent at 1 M, 2 M and 4 M salinity, respectively. The water extraction, turbidity reduction and salinity reduction efficiency were better for DSE with ferrate-pretreatment than compared to DSE alone. DSE's salt rejection rates in the product water were consistently over 95 %, while turbidity reduction was dependent on ferrate dosage used for pretreatment. This process costs an estimated $1.23 per m3 of water extracted from a 4 M brine for a single-pass operation with 95 % heat recoveries.
Digital Object Identifier (DOI)
Thimons, Sean X.; Saxena, Shray; and Den, Walter, "Ferrate-Pretreated Directional Solvent Extraction for Hydraulic Fracturing Produced Water: Technical and Economic Feasibility Studies" (2022). Water Resources Science and Technology Faculty Publications. 22.
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