Explain the significance of measuring % moisture content and % ash content of coal.

The significance of measuring the % moisture content and % ash content of coal is crucial for several reasons:

1. Moisture Content: The moisture content in coal affects its heating value. High moisture content in coal reduces the net heating value. When coal is burned, the moisture content evaporates, meaning energy is wasted in vaporizing the water. This results in lower efficiency of the power plant. In addition, high moisture content makes the coal more difficult to ignite and burn, and it also reduces the coal's ability to generate heat. Therefore, measuring the moisture content helps in determining the quality and efficiency of the coal.

2. Ash Content: The ash content represents the non-combustible components present in coal. This includes minerals like silica, alumina, and iron. High ash content in coal affects the combustion process as it does not burn but remains in the furnace. This can lead to slagging and fouling problems in the boiler. Moreover, the ash produced needs to be disposed of, which can be an environmental concern. Therefore, measuring the ash content helps in assessing the combustion efficiency and environmental impact of using the coal.

In conclusion, measuring the % moisture content and % ash content of coal is significant in determining the efficiency, combustion process, and environmental impact of coal usage.