Effect of Rapid Preheating Treatment on Coal Thermoplasticity and Its Evaluation Method

Influence of Heating Conditions on the Strength of Coke Produced from Slightly-Caking Coal Containing Chemically-Loaded Thermoplastic Components

“…23) It is believed that rapid heating treatment increases mobile components (high mobility low molecular) due to thermal relaxation of coal structure via suppression of cross-linking reaction, resulting coal fluidity is promoted, and it becomes possible to manufacture high-strength coke. 26,27) In addition, IST, MFT, and RST shift to high temperature at large heating rate comparing with small heating rate conditions. Therefore, it is suggested that the increase in coke strength in Case 2 may be caused by suppression of cross-linking formation by increasing the heating rate up to 400°C and thermoplasticity amplification effect by HPC pyridine soluble loading to coal above 400°C in carbonization.…”

“…Meanwhile, as a technique for increasing the percentage of low-quality coal input to a coke production process while simultaneously increasing the strength of the coke produced, researchers have used methods such as SCOPE21 for rapidly heating the temperature region of coal thermoplasticity, while conducting detailed investigations of the corresponding effects; this has revealed that increasing the rate of temperature increase in the fluidity region is an effective method for producing coke from low-quality coal. [6][7][8] Also, it has long been known that pelletization is an effective method for converting non-/slightly-caking coal into coke, and many studies have investigated formed coke; [9][10][11][12][13][14] among the findings that have been reported are the following. (1) Ensuring large particle-to-particle contact area is important for promoting binding between coal particles during the coke production process.…”

“…It is well known that increasing the rate of heating in the thermoplastic temperature region of coal tends to increase fluidity. [6][7][8]21) Therefore, the decreased strength observed for Cases 2-4 may be said to arise from a decrease in bulk density (the formation of foam-like structures) due to excessive fluidity. Our findings thus demonstrate that the decreased strength observed at a higher temperature and faster heating rate is due primarily to excessive swelling -and thus that we must take care to suppress swelling when conducting strength tests to obtain accurate assessments of the net strength of the coke specimens prepared in Fig.…”

“…On the other hand, in the Case 6, which is heat condition of 20°C/min up to 400°C (before IST observed at gieseler fluidity examination for TA), there is a possibility that cross-linking reaction occurring below 400°C is suppressed by rapid heat treatment. [22][23][24][25][26][27] In addition, the thermoplasticity is also increased by mobile components from HPC pyridine soluble loaded. Thus, HPC pyridine soluble loading amount to TA in the Case 6 is smaller than that in the Case 5.…”

Leading Edge of Coal Utilization Technologies for Gasification and Cokemaking

“…In the coal rapid preheating test, the coal was heated slowly to 300 °C in a fluidized bed dryer, and then heated rapidly to 380 °C in a pneumatic preheater, and carbonized in the coke oven Kato et al, 2004, Matsuura et al, 2005. The quality of the obtained coke was measured by the JIS drum strength index (DI 150 15 ) ( DI: Drum Index).…”