Manufacture of Formed Coke by Hot-Briquetting Method (IV)

Abstract

Based on the fundamental studies and the operation results of the pilot plant reported previously, another pilot plant was installed to make formed coke of larger size. Caking coal and non-caking coal are separately pre-heated in two contnuous fluidized bed retorts. The heating temperature of caking coal is lower than that of non-caking coal to prevent agglomerating or sticking in the retort. These temperatures are selected according to the mixing rate and plastic properties of coals used so that the adequate temperature for hot briquetting may be obtained after mixing in a paddle mixer. An oil press of rotary table type is used to make briquettes of 70 mm in height and diameter.A set of carbonizer consists of a pre-carbonizer using hot sand as a heat carrier and a high temperature carbonizer heated internally by hot combustion gas.According to the results obtained by a laboratory test apparatus, non caking coal must not be heated over 600°C, because it becomes innert char, which gives finally abrasive formed coke, even if caking coal is added. It is desirable to pre-carbonize a briquette to prevent it from fissuring due to heat shock.