Development of a Method for Testing the Disintegration Property of Coke during Gasification

Abstract

A new test method for the evaluation of disintegration property of coke during the progress of gasification has been developed in order to simulate the state of coke at the raceway in blast furnace.
This method uses a spouted bed reactor into which heated CO₂ gas or perfect combustion gas containing CO₂ and H₂O is injected at the flow rate enough for fluidizing the specimen coke particles. The cokes which are shot into the reactor react with CO₂ or H₂O, and thereby the strength deterioration progresses at their surfaces. The fine coke particles are generated by the impact or abrasion of fluidizing particles and carried over to the outside by the stream of gas. The fine cokes are collected by a cyclone and the total mass of them is measured continuously.
The curve of showing the amount of fine coke collected against reaction time represents the disintegration property of coke and this seems to be well corresponded to the burning character of coke in the raceway. The two indexes are defined to indicate the test result. One is mean disintegration rate and the other is fine coke ratio. The former shows good correlation to the reactivity of coke matrix with CO₂ and this is well corresponded also to the test value of CSR (coke strength after reaction in a small scale reactor). The latter is correlated to the minimum gasification degree where disintegration of coke surface starts under a certain condition and that seems to be related to the macro-structure of coke.