Influence of preheating of coals before carbonization on coke yield

Correct determination of the technical-economic indices of thermal preparation of coals for carbonization requires objective evaluation of the coke yield. There are a number of contradictory views regarding this problem. Some researchers believe that an increase in carbonization rate should promote a substantial reduction in coke yield while others hold that preheating has no significant influence on this parameter. The present investigation was conducted to determine the coke yield from the carbonization of preheated coals and blends in an experimental 200-kg oven. The well-known method devised by the UKhIN, which is widely employed at coke-chemical enterprises, was used for determination of the coke yield. Gas coal and mixtures containing 70 and 50% gas coal were subjected to carbonization after preheating to 150 to 250/sup 0/C. Preheating was carried out in an experimental apparatus with a capacity of 1 t/h. It was concluded that: The increase in coke yield observed for preheated coals and blends can be attributed to a rise in the concentration of degradation products in the liquid, solid, and gaseous phases; the higher the gas--coal content of the preheated blend, the larger is the absolute increase in coke yield; and the maximum increase in coke yield occurs formore » carbonization of coals and blends preheated to 150/sup 0/.« less