Study on the Hyper-coal Process for Brown Coal Upgrading

Abstract

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.