Abstract
We have recently presented a novel method that not only dewaters but upgrades low rank coals. The method treats coal in non-polar solvent, such as 1-methylnaphthalene, at temperatures below 350℃, and separates the coal into extract, residue, and gaseous product consisting of CO_2 and a negligible amount of hydrocarbon gases at the treatment temperature. The extract is further separated into solvent-soluble fraction, Soluble, and solvent-insoluble fraction, Deposit, at room temperature. In this work twelve low-grade carbonaceous materials including a peat, various kinds of biomasses as well as low rank coals were upgraded and fractionated by this method. The results showed that the moisture in all the raw materials was completely removed without phase change. The raw materials were mainly separated into three solid fractions (Residue, Deposit and Soluble) without heating value loss for all the raw materials. The Solubles and Deposits were almost ash-free, and were respectively rather close to each other in chemical and physical properties regardless of the parent materials. Thus, it was shown that the proposed degradative solvent extraction method can effectively convert a wide range of low grade carbonaceous resources into solid fuels and low-molecular-weight compounds having rather similar chemical and physical properties.
