Ignition temperatures were measured by simulated solid fuel and partia
lly devolatilized coal to establish a model of the solid-fuel ignition
mechanism. The simulated solid fuel is composed of activated charcoal
, salicyclic acid and bentonite, which are the main three components o
f real solid fuels. The partially devolatilized coal was prepared by h
eating Taiheiyo coal in a nitrogen atmosphere at a temperature of 720K
to obtain solid fuels with different volatile matter contents. Igniti
on temperature was measured by using an air-flow type thermobalance wh
ich can realize uniform gas flow within a layer of the solid fuel spec
imen during heat-up operation. The results obtained are as follows. 1)
The ignition of solid fuels took place when the most suitable flammab
le gas (mixture of volatile matter and oxygen) and hot spot were prepa
red at the same time. 2) The ignition condition of solid fuels can be
shown within a triangular region drawn on a space with the ignition te
mperature as the Y axis and the excess oxygen ratio in the fuel layer
as the X axis respectively, and the ignition temperatures are estimate
d from this ignition-region map.