Question

What happens when coal is expanded during the plastic stage of caking?

(a) Closed texture coke is obtained

(b) Highly swollen open texture coke is obtained

(c) There is no change in the coal

(d) Coal breaks into a number of pieces

The question was posed to me by my college director while I was bunking the class.

This is a very interesting question from Secondary Solid Fuels in division Fuels and Combustion of Engineering Chemistry II

Answer 1

Correct option is (b) Highly swollen open texture coke is obtained

The best explanation: If the coal is free to expand at plastic stage, it produces a highly swollen open texture coke produced from strongly coking coal. If this expansion is suppressed by the retaining wall, a dense coke having fine pore structure is produced.