PRODUCTION OF HIGH-GRADE CARBONACEOUS MATERIALS AND FUEL HAVING SIMILAR CHEMICAL AND PHYSICAL PROPERTIES FROM LOW GRADE CARBONACEOUS RESOURCES BY DEGRADATIVE SOLVENT EXTRACTION

摘要

It is without question that effective methods are requested to utilize low grade carbonaceous resources such as low rank coal, peat, biomass waste, etc. as energy resource, chemical feed stocks, and so on. The low grade resources have many drawbacks to be overcome for their effective utilization such as high moisture content, high ash content, low heating value, non-uniformity, and so on. Overcoming these drawbacks, the authors have recently proposed a degradative solvent extraction method which treats such low grade carbonaceous resources in a non-hydrogen donor at around 350 °C, under pressure, using a batch autoclave to dewater without phase change, to remove oxygen functional groups, and to produce low-molecular-weight compounds. The core concept underlying this method involves exposing the entire sample to thermal reactions in a nonpolar solvent at around 350 °C. The anticipated thermal reactions under these conditions include deoxygenation reactions consisting of dehydration and decarboxylation without primary decomposition reactions accompanying the disruption of C-C bonds. The products formed during the thermal reactions at around 350 °C are then filtrated at the same temperature to recover the extract and residue (the latter is termed residue in this work). The extract is further separated into two fractions at room temperature: the fraction that precipitates as a solid (deposit) and the soluble fraction (soluble). The soluble fraction is also finally recovered as a solid by removing the solvent. The solubles consisted of low-molecular-weight compounds with a peak molecular weight at around 300, and the fractions softened and melted below 90 °C.