Chemical Degradation of HPAM by Oxidization in Produced Water: Experimental Study
Bibliographic record
Abstract
Abstract Hydrolyzed polyacrylamide (HPAM) degradation is a critical technical and environmental concern in oilfields, where HPAM is extensively used in drilling or chemical enhanced oil recovery process, especially polymer flooding. However, how to treat the residual HPAM in produced water has become an urgent issue. In this work, the HPAM chemical degradation characteristics were investigated through series of laboratory experiments. The oxidative, ionic and thermal degradation of HPAM were studied, and the feasibility of HPAM degradation by oxidization was examined. The results will help the oil industry to find a practical and optimal HPAM treatment method. In the experiments, the oxidization effects of photo-catalysis and strong oxidants at different temperatures, as well as the presence of typical ions with different concentrations on HPAM degradation process were studied. In addition to this, the related reaction mechanism during the degradation process was investigated. The experimental results show that the natural sunlight has little effect to excite the HPAM degradation, while the light generated by a high-pressure mercury lamp with a wave length λ < 385 nm can stimulate the catalytic function of TiO2, which consequently accelerates the HPAM degradation reaction. Also, the strong oxidant such as Na2S2O8 and H2O2 can greatly improve the HPAM degradation, especially at higher temperature with a degradation degree η less than 0.15. In the HPAM-Na2S2O8 system, free radical reaction is the main mechanism accounting for the chain scission of HPAM, while the strong reduction-oxidation of hydroquinone (HQ) and generation of H2O2 are the dominant reason for HPAM degradation in HPAM-hydroquinone system, which makes the HQ a stronger reagent for HPAM degradation compared with Na2S2O8. The degradation degree of HPAM is significantly affected by the ion type in produced water, decreasing in an order of Al3+ > Mg2+ > Ca2+ > Na+ under the same ion concentration. This study not only probed into the HPAM viscosity loss problem caused by polymer chemical degradation, but also provided the necessary guide for the residual HPAM removal in produced water, which will boost the application of polymer flooding process.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".