STUDY ON IGNITION CHARACTERISTICS OF SOLI D FUELS

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.