Nobuyuki Komatsu

Study on the Hyper-coal Process for Brown Coal Upgrading

ABSTRACT The Hyper-coal process is a coal refinery process that makes an ash-free coal by thermal extraction and solid-liquid separation technology. This study investigates the upgrading of brown coal by applying the Hyper-coal process. Several kinds of bituminous, sub-bituminous, and brown coals were thermally extracted with 1-methynaphthalene using a high temperature-extraction/filtration unit. As a result of these coal extraction tests, Hyper-coal (HPC) yields of more than 60% weight (daf) were obtained from the bituminous coals, but less than 30% weight (daf) were obtained from brown coals. Hyper-coal contains negligible ash (<500 PPM) and high heat value (>8000 kcal/kg). In addition, the excellent thermal plasticity of this product may facilitate metallurgical applications, such as coke binder. In the case of brown coal, the ash content in the insoluble coal is less than 5%, since the parent coal has only 3% ash. In addition, the elimination reaction of the oxygen containing functional groups yields a substantial increase in heat value. Thus, the Hyper-coal process is an effective way to upgrade brown coals, producing not only ash-free coal but also low ash and high heat value coal.

Prebaked Anode from Coal Extract (3) — Carbonization Properties of Hypercoal and Its Blends with Binder Pitch

The preparation of prebaked anodes from coal using solvent extraction technology was investigated. Several bituminous coals were extracted with methylnaphthalene-based solvent under pressurized nitrogen atmosphere at 653K, and ash-free and high purity coal extract (Hypercoal, HPC) was obtained. It was found that the HPC can be utilized as an additive for binder pitch of anode manufacturing; the HPC improves the coke yield of the pitch and reduces the ash content of the binder. It was also found that a suitable modified HPC was self-sinterable, and was successfully molded and carbonized without binder pitch to result of dense carbon specimen. These results suggest the possibility for coal-based raw materials for prebaked anodes

Prebaked Anode From Coal Extract (2) - Effects of the Properties of Hypercoal-Coke on the Preformance of Prebaked Anodes

The preparation of prebaked anodes utilizing coal solvent extraction technology is reported. A steaming coal was extracted with methylnaphthalene-based solvent under pressurized nitrogen atmosphere at 653K, and ash-free coal extract (Hypercoal, HPC) was obtained. The HPC was further heat-treated at 633 to 673 K in the presence of the methylnaphthalene solvent to alter the carbonizing properties of HPC. It was found that adjusting the H/C atomic ratio of HPC in the range 0.6-0.65 suppressed excess dilatation ability of the HPC and produced anode-quality coke. The effect of heat treatment temperature of the HPC on the resultant properties of the HPC coke (HPCC) was also investigated. It was confirmed that HPC is a suitable source of anode coke due to the low content of impurities such as sulfur, nickel, vanadium, and good chemical stability.