A study was made of rapid carbonization of coal in entrainment by composite factorial design of test-runs. From the data obtained through the operation of a 4-in-diameter flash carbonizer, the effects and interactions of the variables were determined and represented by three-dimensional models called response surfaces. These surfaces indicated the essential variables for each product yield or quality and showed the trend toward optimum values of these responses. Internal heating was shown to be superior to external heating from the standpoint of producing a uniformly devolatilized char with higher throughput rates. Illustrating the method and the results obtained, the quality of the char, defined as the amount of volatile matter (vm) remaining in it, and the char yield for the internally and the externally heated carbonizer are shown as a function of the temperature, coal-feed rate, and composition of the entraining gas. Optimum char quality of 15 percent vm with the highest throughput rate, 750 g/h, was achieved by means of internal heating at 1,900 deg f, which resulted in a char yield of 1,075 lb/ton of coal carbonized.
Fuel (London), V. 50, October 1971, PP. 381-393