What is coal ash
The ash content of coal is the non-combustible mineral residue remaining after complete combustion of coal, usually expressed as a mass percentage. It is one of the important indicators for evaluating coal quality and directly affects the calorific value, combustion efficiency and environmental pollution level of coal. This article will introduce in detail the definition, sources, influencing factors of coal ash and its impact on industrial applications.
1. Definition and source of ash content of coal
The ash content of coal refers to the solid residue remaining after complete combustion of coal under standard conditions (usually 815°C). These residues are mainly derived from inorganic minerals in coal, including clay, quartz, sulfide, carbonate, etc. The content of ash varies depending on the type of coal and the environment in which it was formed.
| Type of coal | Ash content (%) |
|---|---|
| anthracite | 6-15 |
| bituminous coal | 10-30 |
| lignite | 20-40 |
| peat | 30-50 |
2. Factors affecting the ash content of coal
The ash content of coal is affected by many factors, including the following aspects:
1.coal-forming environment: During the formation process of coal, the surrounding geological conditions and mineral content directly affect the amount of ash.
2.Mining and processing: The rocks and soil mixed in during the mining process will increase the ash content, and the washing process can reduce the ash content.
3.transportation and storage: Impurities may be mixed in during transportation and storage, further increasing the ash content.
3. The impact of coal ash content on industrial applications
Coal with high ash content can cause the following problems in industrial applications:
1.Reduce calorific value: Ash is a non-combustible substance. The higher its content, the lower the effective calorific value of coal.
2.Increase processing costs: High-ash coal requires more processing and purification, increasing production costs.
3.environmental pollution: Burning high-ash coal will produce more dust and solid waste, exacerbating environmental pollution.
| Ash content (%) | Effect on calorific value | Impact on the environment |
|---|---|---|
| <10 | Less impact | lower |
| 10-20 | medium impact | medium |
| >20 | significantly reduced | higher |
4. How to reduce the ash content of coal
In order to reduce the impact of ash on coal quality, the following measures are usually taken:
1.Washing and processing: Remove minerals from coal and reduce ash content through physical or chemical methods.
2.Optimize mining: Minimize the mixing of rocks and soil during mining.
3.Mixed use: Mix high-ash coal with low-ash coal to balance calorific value and cost.
5. Summary
The ash content of coal is an important indicator for evaluating coal quality and directly affects the calorific value, combustion efficiency and environmental impact of coal. By understanding the sources and influencing factors of ash, effective measures can be taken to reduce ash content, improve coal utilization efficiency and reduce environmental pollution. For industrial users, choosing low-ash coal or reducing ash through processing is key to optimizing energy use.
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