Rapid preheating of coal was conducted in entrained and fluidized beds. Preheated coal particles were directly introduced to a carbonizer to produce coke under loading pressure of 0.97 MPa. Effects of preheating conditions of coal, i.e., preheating temperature and soaking time, on the properties of produced coke, i.e. micro and tensile strengths, true density and porosity were discussed.
In the case of entrained bed, bubble formation in coke produced from caking coal was slightly restrained by the rapid preheating. As to the slightly caking coals, preheating at high temperature with long soaking time led to the reduction in the strength of coke. In the case of slightly caking coal, the rapid preheating at the temperature lower than 400°C increased the strength of produced coke and the effects of soaking time was hardly observed.
Lastly, it was demonstrated that the rapid preheating of slightly caking coal at 350°C in the fluidized bed could increase the strength of coke drastically.
