Towards the Improvement of the Efficiency of Oil Sands Froth Treatment
Bibliographic record
Abstract
Introduction Over fifteen million cubic meters per annum of synthetic crude are produced in Alberta from the mined oil sands. The production is projected to increase to nearly one million barrels per day by 2011(1). As high quality ore deposits are depleted, it will be necessary to rocess poorer quality ores; that is ores with less bitumen and more fines. At the same time, it is desirable to reduce the process energy requirements. There are two main stages to oil sands processing: extraction and froth treatment. The most common extraction process is hot water bitumen extraction where bitumen is produced in a froth consisting of bitumen, water, and inorganic solids. Poorer quality oil sand froths have lower oil content and higher contents of water and solids(2). There are currently two commercialized froth treatment processes in Alberta, here termed the "Syncrude Process" and the "Albian Process". In the Syncrude process, the froth is diluted with naphtha to decrease the density and viscosity of the bitumen and to promote coalescence of emulsified water. Phase separation is achieved with centrifuging. The Albian process has been tested at the pilot scale and the commercial process is now under construction. In this process, a paraffinic solvent is added to the froth to reduce the bitumen density and viscosity, and to promote flocculation of the emulsified water and suspended solids. Some asphaltenes are also precipitated to achieve a product suitable for a conventional refinery. Phase separation is achieved with gravity settling. In both processes, it is desirable to reduce energy costs and minimize the water and solids content of the product bitumen. The two froth treatment processes are investigated in this work using laboratory scale approximations. The goal is to identify the optimum solvent-to-bitumen ratios and temperatures for the effective treatment of froth produced from oil sands of various qualities. The effective of the treatment is assessed in terms of bitumen recovery and the water content of the bitumen product. EXPERIMENTAL Oil sand samples of three different qualities were obtained from Syncrude Canada Ltd. (Table 1). The bitumen, water, and solids contents as were determined at the Syncrude Research Centre as reported elsewhere(3). According to these parameters, the oil sands are termed low- (LQOS), average- (AQOS) and high-quality ores (HQOS) Bitumen froth was extracted from the oil sand using a batch extraction unit (BEU) at 80 °C and following the Syncrude standard extraction procedure(3). Subsamples of froth from the batch extractions were collected and assayed for oil, water and solid contents using the "Syncrude method"(3). Only primary froth was used for froth treatment experiments because of the low amount of secondary froth. For bitumen extraction from HQOS and AQOS, no chemicals were used. For LQOS, sodium hydroxide was used. The maximum bitumen recovery of almost 100% was achieved with the addition of approximately 0.025 wt% NaOH (on an oil sand basis). The effect of NaOH addition during extraction was also investigated for the low quality oil sand froth. Different NaOH levels from 0 to 0.125 wt% were considered.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 teacher head, 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".