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Record W6921639445 · doi:10.7939/r3-czxs-hk95

Oxidative Coal Dissolution a Systematic Study

2023· dissertation· en· W6921639445 on OpenAlexaboutno aff

Bibliographic record

VenueUniversity of Alberta Library · 2023
Typedissertation
Languageen
FieldEngineering
TopicCoal Properties and Utilization
Canadian institutionsnot available
Fundersnot available
KeywordsCoalYield (engineering)Carbon fibersDissolutionAtmospheric pressureSelectivityOxygenLiquid fuel

Abstract

fetched live from OpenAlex

The coal industry in Canada boasts abundant reserves, with significant potential for value addition through innovative processes. Oxidative coal dissolution (OCD) emerges as a promising method to generate high-value products from coal, using air as the oxidant, making it a cost-effective and environmentally favorable approach. This thesis focuses on evaluating the impact of critical operating parameters on OCD, seeking to enhance its efficiency and product selectivity for large-scale applications. The research started with a comprehensive overview of coal composition, ranks, and properties, followed by an exploration of the oxidation process itself. The study narrows down the scope to oxygen in air as the oxidant and explores the engineering challenges associated with OCD, including different operating parameters such as oxidant type, oxidant availability, temperature, time, water-to-coal ratio, and pH control. An initial set of experiments at atmospheric pressure with temperatures up to 95 °C revealed that OCD at low temperatures has limited carbon yield to liquid products. To overcome this, OCD reactions at elevated pressures of 5 MPa and temperatures ranging from 90 to 180 °C were conducted. These conditions significantly improve carbon yield to liquid products, providing a better understanding of carbon conversion and product distribution. However, overoxidation remains a challenge at higher temperatures and pressures, leading to increased carbon conversion to gaseous products. To address this issue, further experiments at 1 MPa pressure at same temperature range were performed, improving carbon selectivity to liquid products, though at the cost of decreased yield. It was found that the optimal selectivity and yield towards liquid products occur at 150 °C, Additionally, an unexpected increase in heating value was observed in the residue product after OCD reactions at 90 °C, contradicting conventional expectations. To explore this phenomenon further, additional reactions were conducted using nitrogen instead of air, revealing that the decrease in the oxygen-to-carbon molar ratio responsible for the heating value increase is not solely attributed to the oxidative coal dissolution process. Instead, a hypothesis suggests that under specific reaction conditions, a portion of initially bonded oxygen within the coal molecule is liberated, possibly promoting the exudation of oxygen-rich organic compounds from the coal porous structure.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Qualitative · Consensus signal: Qualitative
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.225
Threshold uncertainty score0.734

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

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.

Opus teacher head0.009
GPT teacher head0.179
Teacher spread0.170 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designQualitative
Domainnot available
GenreEmpirical

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".

Quick stats

Citations0
Published2023
Admission routes1
Has abstractyes

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