Optimum conditions for preparing liquid fuel (LF) by supercritical ethanolysis (SCE) of wheat stalk powder (WSP) were determined by orthogonal experiment. Fuel properties, including pH, density, viscosity, flash and ignition temperatures, heating value, water content, and distillation range, of the LF obtained under the optimum conditions were measured. Subsequent treatments, including dehydration and distillation, were conducted upon the LF. The LFs before and after the treatments were analyzed with gas chromatography/mass spectrometry (GC/MS). SCE of model substances cellulose and lignin was also examined for understanding the formation pathways of typical organic compounds in the LF. The results show that the optimum conditions for preparing LF are 300 °C (reaction temperature), 10 min (reaction time), and 1:24 (WSP/ethanol ratio). After treatments, fuel properties of the LF are eligible for practical use. The main components in the LF include shorter chain carboxylic acids and their ethyl esters, furan derivatives, cyclopentanones, phenol derivatives, benzene derivatives, aromatic acid derivatives, longer chain carboxylic ethyl esters, and sterides.

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Ash in Guiding subbituminous coal (GSBC) was removed by treatment with dilute acids. The treated GSBC (TGSBC) was extracted with isopropanol (IP) to afford IP-extractable fraction (IPEF). TGSBC was sequentially extracted with petroleum ether, carbon disulfide, acetone, and methanol. Octane-1-thiol and thiophene were selected as model compounds (MCs) for organic sulfurs in GSBC. MCs and extracted residue (ER) of TGSBC were electrolyzed in an aqueous NaCl solution. Reaction mixtures from the electrolysis of MCs were extracted with cyclohexane. The electrolyzed extracted residue (EER) was extracted with the same method as TGSBC. The extracts were analyzed with gas chromatography/mass spectrometry (GC/MS). ER and EER were analyzed with Fourier transform infrared (FTIR) spectrometry. Three organic sulfurs were detected in IPEF from TGSBC with GC/MS. FTIR analysis shows that ER electrolysis increased oxygen-containing functional groups but decreased organic sulfurs. Disulfide, sulfoxide, sulfone, and sulfonic acid were detected by GC/MS and FTIR analyses. The mechanism for removal of organic sulfur during GSBC electrolysis was discussed.

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