The formation of precipitates (scales) during reinjection limits the reuse of oil and gas production water (produced water) for additional oil recovery. Selective removal strategies that target Ba and Sr, the primary scale-forming cations, would limit produced water treatment costs, reduce waste generation, and increase produced water reuse. A novel treatment technique for targeted Ba and Sr removal, complexation with polyelectrolyte polymers, is compared with chemical precipitation (sulfate addition and precipitative softening) for the removal of Ba and Sr from Kansas oil field brines. Four polymers were examined for cation removal, both with and without ultrafiltration: poly-vinyl sulfonate (PVS), poly(4-styrenesulfonate) (PSS), polyacrylic acid (PAA), and poly(4-styrenesulfonic acid- co -maleic acid) (PSSM). PSSM and PSS were effective for Ba and Sr removal from the lower salinity brine (TDS of 31 000 mg L −1 ), but exhibited limited Sr removal in the absence of Ba in the high salinity brine (TDS of 92 000 mg l −1 ). Similar results were achieved in both brines using sulfate addition. PSSM used in conjunction with ultrafiltration removed >99% of initial Sr and Ba from the lower salinity brine, while removing only 65% and 78% of Mg and Ca, respectively. These results compare favorably to precipitative softening, which removed >90% of all divalent cations from the same brine but was less selective for Ba and Sr. PAA plus ultrafiltration removed 58% of Sr (and 68% of Ca) from the high-salinity brine at pH 9. While increased Sr removal can be achieved by polymer-assisted ultrafiltration, further development of this process, including methods for polymer recovery and regeneration, will be needed to improve its performance compared to precipitative softening.
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Investigating the effect of refining parameters on acetic acid removal and the quality of crude epoxidized soybean oil
Abstract Washing crude epoxidized oil is an indispensable step for the removal of residual acetic acid and unreacted hydrogen peroxide after epoxidation. There are many studies on the epoxidation of vegetable oils but there are many discrepancies in the washing process which likely leads to water wastage, excess use of neutralizing agent, and additional processing time. Hence, this study aims to optimize the washing step by analyzing the quality of each washing step and developing a model that can predict the amount of acid removed. Soybean oil (1.5 kg) was epoxidized at 60°C for 5.5 h using Amberlite IR 120H as a heterogeneous catalyst. To determine the optimum water washing level, process parameters such as number of washing cycles (1–5), proportion of epoxidized oil to water volume (1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5), and water temperature (20, 40, and 60°C) were examined. The main responses were the residual acid value and pH of the washed epoxidized oil. Results revealed that 64% of the acid was removed after 5 washing cycles irrespective of the washing water temperature and proportion. In contrast, approximately 57% of the acid was removed in the first two washing cycles. Increasing the temperature of the water affected acid removal; with approximately 54% of acid removed at 20°C compared to 60% at 60°C. Doubling or tripling the amount of water needed above a 1:0.5 ratio did not significantly affect the amount of acid removed. The model developed was significant with a predictedR2of 96% and a root mean square error (RMSE) of 1.1 when the model was validated at different washing scenarios. Therefore, this study shows that it is possible to significantly reduce the amount of water used and processing time while maintaining resin qualities.
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- Award ID(s):
- 1839895
- PAR ID:
- 10539325
- Publisher / Repository:
- Journal of the American Oil Chemists' Society
- Date Published:
- Journal Name:
- Journal of the American Oil Chemists' Society
- Edition / Version:
- 1
- Volume:
- 1
- Issue:
- 1
- ISSN:
- 0003-021X
- Page Range / eLocation ID:
- 12866
- Subject(s) / Keyword(s):
- acetic acid removal, crude epoxidized soybean oil
- Format(s):
- Medium: X Size: 1MB Other: 1
- Size(s):
- 1MB
- Sponsoring Org:
- National Science Foundation
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