Question

Why does over feed burning system takes longer time for complete burning?

(a) The volatile matter will be cooler at initial

(b) Due to the presence of dust and ash

(c) The effect of design of system

(d) Effects of air fuels on the system

I got this question in semester exam.

This interesting question is from Principle of Stoker topic in section Steam Power Plant of Energy Engineering

Answer 1

Right choice is (a) The volatile matter will be cooler at initial

To explain I would say: In case of over-feed burning, the volatile matter will be considerably cooler than the furnace gases and therefore it requires longer time for complete burning and also the air passes though incandescent zone and then enters ignition zone. This may create a tendency to form smoke.