Abstract
The authors have recently proposed a novel method that not only dewaters but upgrades low-grade carbonaceous resources such as biomass, peat, lignite, and sub-bituminous coals. The method comprises a treatment of the raw materials in non-polar solvent, such as 1-methylnaphthalene, at temperatures below 350°C, and subsequent separation of the upgraded samples 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. The method can produce a large amount of Soluble which consists of ashless, carbon-rich, low-molecular-weight compounds. From the viewpoint of practical application of the proposed method, it is desired to reduce the energy required to separate the Soluble from solvent. In this study the possibility to recover the Soluble as solid by using solvent saturated with the Soluble was examined.
