From 1962, we have done several tests by the Preheated Coal Carbonisation Process at our laboratory and middle scale plant, and commercial coke oven. We used charging coal which mixed with more much quantity of Japanese coals from the point of utilization of domestic coals.
Results of these tests, for example, were following,
Seam Normal Preheating
Strong coking coal (import) 52-56% 20-40%
Weakly coking coal (import) 4-6%
Weakly coking coal (Japanese) 38-44% 30-70 %
Non or slightly coking coal (Japanese)-0-20 %
And preheated coal cokes have very nice coke strengths that 15mm indexes of JIS drum test are more 93.
Productivity for coke oven increases about more 20%, and probably any troubles shall not be happened by introducing preheating process for full scale coke oven.
Now, we believe that the Preheated Coal Carbonisation Process shall be able to use practicaly for commercial coke oven in Japan.