Question

Which of the low grade coal is suitable for pulverising?

(a) Coals containing high moisture content

(b) Coals with more percentile of impurities

(c) Coals with low fixed carbon rating

(d) Coals containing high percentile of ash

I had been asked this question during a job interview.

This is a very interesting question from Pulverised Coal in chapter Fuels and Combustion of Engineering Chemistry II

Answer 1

Right choice is (d) Coals containing high percentile of ash

The explanation is: Ash contains many minerals, due to which when coal powder is allowed to mix with air most of its minerals form oxides and escapes out, due to which it helps in increasing the rate of combustion of coal. This process is very useful for Indian coals because they contain a lot of ash content in them.