Development of the innovative coke-making process, SCOPE21 (Super Coke Oven for Productivity and Environmental enhancement toward the 21st century) has been conducted by Japan Iron and Steel Federation (JISF). It has been performed from 1994 to 2003. The purposes of SCOPE21 process are as follows.
1) Increasing the blending ratio of poorly-coking coal in coal charge, in order to reduce the cost of coke and expand the use of available coal resources, 2) In SCOPE21, the coking time in coke ovens can be remarkably shortened due to the rapid preheating of coals up to 330-380°C. The shortening of coking time leads to higher productivity of coke, and therefore to the decrease of oven numbers in the case of identical production of coke compared to conventional coke-making process.
These two purposes are supposedly achieved by applying a coal rapid preheating technology to the new coke-making process. In this process, coal is rapidly preheated to the temperature range from 330°C to 380°C and then charged into coke oven. Therefore it is important to study the effect of rapid preheating on coal thermoplas-ticity and the strength of resultant coke.
It is generally known that the thermoplasticity of coals is enhanced when the coals are rapidly heated through their thermoplastic stages. However, when the coals are rapidly preheated to 330-380°C, the effect of rapid preheating on the subsequent development of coal thermoplasticity has been unclear.
Here, changes of thermoplastic behavior by this preheating were studied using a needle penetrater. Conse-quently, it was found that the thermoplasticity of coals was enhanced when the coals are rapidly preheated to 330-380°C, even when the slow heating rate (3°C/min) was applied through the following thermoplastic stages.
