Relationship between Chemical Structure of Caking Additives Produced from Low Rank Coals and Coke Strength

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

“…Therefore, it was not possible to obtain chemical evidence that HPC pyridine soluble was introduced into the coal structure by this method. As is well-known, although HPC consists of hundreds to thousands of molecular weights, 18) HPC pyridine soluble is composed with lower molecular weight than original HPC, because DTG curve of the soluble gave the main peaks at around 250 and 450°C (HPC also provides the main peaks at same temperatures), and the former peak does not observed for HPC pyridine insoluble. 5) In addition, it was found that the interaction of HPC pyridine soluble and coal occurs during heat treatment of chemically loaded coal prepared by this method.…”

“…SUS tube was used for coke preparation. 18) After charging the tube [dimensions: 20 mm (diameter) × 50 mm (height)] with specimens of particle size 0.5-1.0 mm, sample was applied with a load of 200 g and carbonized for 30 min in a muffle furnace under N 2 gas flow at 1 000°C. Table 2 lists the heating conditions applied when the tube was used.…”

Reforming of Low-rank Coal by Chemical Upgrading

“…On the other hand, chemical structure of extracts obtained from low-rank coals is significantly different from those from caking coals. 9) It was reported that the average number of aromatic rings in low rank coals is about 1-2, much low compared to caking coals with more than 4 rings. [9][10][11] Koyano et al investigated the effect of the aromatic ring size of model compounds added to coals on the coke strength of blended coals, and reported that the coke strength was increased by adding more than 4 aromatic rings and the effect was enhanced with increase in the number of aromatic rings.…”

“…9) It was reported that the average number of aromatic rings in low rank coals is about 1-2, much low compared to caking coals with more than 4 rings. [9][10][11] Koyano et al investigated the effect of the aromatic ring size of model compounds added to coals on the coke strength of blended coals, and reported that the coke strength was increased by adding more than 4 aromatic rings and the effect was enhanced with increase in the number of aromatic rings. 12) Sakimoto et al also reported that the aromatic ring size of HPCs obtained from the extraction of low-rank coals with 1-methyl naphthalene at 673 K was around 3, although the extraction yield was 20-26 mass%, daf.…”

“…12) Sakimoto et al also reported that the aromatic ring size of HPCs obtained from the extraction of low-rank coals with 1-methyl naphthalene at 673 K was around 3, although the extraction yield was 20-26 mass%, daf. 9) In the present study, in order to utilize low-rank coals efficiently, polar solvents were used as an extraction solvent, because a higher extraction yield can be expected. Furthermore, the effect of extraction temperature was investigated.…”