Investigation of Pressurized Entrained-Flow Kraft Black Liquor Gasification in an Industrially Relevant Environment
Bibliographic record
Abstract
The University of Utah's project 'Investigation of Pressurized Entrained-Flow Kraft Black Liquor Gasification in an Industrially Relevant Environment' (U.S. DOE Cooperative Agreement DE-FC26-04NT42261) was a response to U.S. DOE/NETL solicitation DE-PS36-04GO94002, 'Biomass Research and Development Initiative' Topical Area 4-Kraft Black Liquor Gasification. The project began September 30, 2004. The objective of the project was to improve the understanding of black liquor conversion in high pressure, high temperature reactors that gasify liquor through partial oxidation with either air or oxygen. The physical and chemical characteristics of both the gas and condensed phase were to be studied over the entire range of liquor conversion, and the rates and mechanisms of processes responsible for converting the liquor to its final smelt and syngas products were to be investigated. This would be accomplished by combining fundamental, lab-scale experiments with measurements taken using a new semi-pilot scale pressurized entrained-flow gasifier. As a result of insufficient availability of funds and changes in priority within the Office of Biomass Programs of the U.S. Department of Energy, the research program was terminated in its second year. In total, only half of the budgeted funding was made available for the program, and most of this was used during the first year for construction of the experimental systems to be used in the program. This had a severe impact on the program. As a consequence, most of the planned research was unable to be performed. Only studies that relied on computational modeling or existing experimental facilities started early enough to deliver useful results by the time to program was terminated Over the course of the program, small scale (approx. 1 ton/day) entrained-flow gasifier was designed and installed at the University of Utah's off-campus Industrial Combustion and Gasification Research Facility. The system is designed to operate at pressures as high as 32 atmospheres, and at temperatures as high as 1500 C (2730 F). Total black liquor processing capacity under pressurized, oxygen-blown conditions should be in excess of 1 ton black liquor solids per day. Many sampling ports along the conversion section of the system will allow detailed analysis of the environment in the gasifier under industrially representative conditions. Construction was mostly completed before the program was terminated, but resources were insufficient to operate the system. A system for characterizing black liquor sprays in hot environments was designed and constructed. Silhouettes of black liquor sprays formed by injection of black liquor through a twin fluid (liquor and atomizing air) nozzle were videoed with a high-speed camera, and the resulting images were analyzed to identify overall characteristics of the spray and droplet formation mechanisms. The efficiency of liquor atomization was better when the liquor was injected through the center channel of the nozzle, with atomizing air being introduced in the annulus around the center channel, than when the liquor and air feed channels were reversed. Atomizing efficiency and spray angle increased with atomizing air pressure up to a point, beyond which additional atomizing air pressure had little effect. Analysis of the spray patterns indicates that two classifications of droplets are present, a finely dispersed 'mist' of very small droplets and much larger ligaments of liquor that form at the injector tip and form one or more relatively large droplets. This ligament and subsequent large droplet formation suggests that it will be challenging to obtain a narrow distribution of droplet sizes when using an injector of this design. A model for simulating liquor spray and droplet formation was developed by Simulent, Inc. of Toronto. The model was able to predict performance when spraying water that closely matched the vendor specifications. Simulation of liquor spray indicates that droplets on the order 200-300 microns can be expected, and that higher liquor flow will result in better distribution of liquor in the reactor.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".