Carbon attrition during the fluidized combustion and gasification of coal. Quarterly technical progress report, 1 December 1981-28 February 1982

Activity has been concentrated in operating the apparatus and testing the procedure described in the DOE Report/PC40796-1. The work aimed, in particular, to explore the effect of bed temperature and oxygen content of fluidizing gas on instantaneous rates of generationof carbon fines by attrition during combustion of batches of 4760-6350 ..mu..m South Alfrican coal. Time-resolved bed carbon particle size distributions have also been determined in a separate combustor by means of the basket technique under the same conditions attrition experiments were made. The purpose was that of correlating instantaneous attrition rates to bed carbon loading and exposed surfaces. Experiments carried out during the quarter 1 December 1981-28 February 1982 have: (1) confirmed the peculiar trend of instantaneous elutriated carbon rates as a function of time; (2) shown the importance of basket technique in providing data, such as bed carbon average and particle size distribution, of relevance in analyzing carbon elutriation data with the view of understanding attrition mechanisms; and (3) suggested that attrition rate constant can be determined by batch operation of the two-exit head 40 mm ID combustor rather than the more costly continuous operation of the 140 mm ID combustor as done before.