Bibliographic record
Abstract
Coal, a nonrenewable fossil fuel, which has been used since ancient times, is one of the major sources of energy at present as well. Coal use is associated with several operational and environmental problems. Most of the high-grade coals have already been extracted, so coal left for future use is more of low grade with high moisture and ash content. Environmental issues related to coal combustion are multifaceted and are threatening the sustainability of coal use, mostly in power generation and gasification. There are quite efficient technologies that do exist for controlling pollutants such as oxides of nitrogen and sulfur, trace elements, and fine particulate matter. However, one of the serious problems facing the future of coal is emission of carbon dioxide—a greenhouse gas leading to climate change. Coal is still going to be a major player in the global energy spectrum over next 30–40 years and, in particular, for the countries such as India and China. However, the sustainable future of coal depends on mitigating these pollutants and GHG emissions. This chapter reviews the advanced characterization of coal so as to link the coal properties to operational problems such as unburned carbon and ash-related issues. The beneficiation of coal, both physical and chemical, has been included to improve the coal quality in order to reduce these emissions. The environmental issues related to emissions of NOx, SOx, trace elements and fine particulate matter, and postcombustion technologies to reduce these emissions have been presented as well. The utilization of such technologies and installation of pollution control devices can meet stringent regulatory emission limits except GHGs emission. Advanced combustion technologies, such as supercritical, ultrasupercritical boilers, integrated gasification combined cycle, and integrated gasification fuel cell, increase electricity generation efficiency and thereby reduce the GHG emissions per unit of electricity. There are a number of carbon capture technologies, including precombustion, postcombustion, oxy-firing, and chemical looping combustion, those aid to reduce GHG emissions. Current status for carbon capture and storage is also presented in this chapter. The utilization of high-efficiency low-emission technologies, including coal beneficiation, advanced combustion technologies, installation of pollution control measures, and the deployment of carbon capture and storage technologies, can leverage the coal use sustainability.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.003 | 0.002 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.224 | 0.110 |
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".