Bituminous rank coal, being appeared in heating up to plastic range (370-420℃) of coal, has a caking characteristic and it must be removed in order to be used in fluidized bed reactor for smooth operation.
Coal pretreatment and gasification were studied in a 3 inch diameter fluidized bed at atmospheric pressure.
To find optimum conditions of pretreatment, that is, weight loss of volatile matter is minimum and caking property is destroyed, operation temperature (330-440℃), residence time (10-30 minutes), and oxygen to coal ratio (0.08, 0.16, 0.24) has been changed.
Caking property was determined by means of Free Swelling Index method.
The optimum operating conditions has been found from the pretreatment experiments that the oxygen to coal ratio is 0.08 and residence time is 10 minutes at the temperature 440C.
Weight loss of coal resulted from the pretreatment was 19 percent of its inherent volatile matter contents.
The ratio of carbon monoxide to carbon dioxide and the sum of carbon monoxide and hydrogen amounts were increased with bed temperature in coal gasification.