摘要: A degradative solvent extraction at around 350℃ for low-rank coal or biomass wastes upgrading and fractionation was proposed in our previous work. The extraction yield of low-rank coal is relatively lower than that of biomass. In this work the blends of low-rank coal and biomass were treated by this method at 350℃ to investigate the interaction between them. The results showed that the yields and elemental compositions of the extracts obtained from the blends were slight different to the calculated results, which were calculated by assuming that there was no interaction between the coal and biomass. The slight promotion of yield was judged to be caused by the catalytic action of the minerals in the coal for thermal decomposition of biomass. It was worth to note that the elemental composition, molecular weight distribution, chemical structure, thermal decomposition behavior and thermoplastic behavior of the extracts obtained from low-rank coal, biomass and their blend, were rather similar to each other, independent of the properties of the raw feedstocks. Overall, the interaction between low-rank coal and biomass during the extraction was not significant. On the other hand, the proposed degradative solvent extraction method was fit not only by single low-rank coal and biomass but also by their blends to produce the product having similar physicochemical properties. This implied that an industrial system of degradative solvent extraction can use coal, biomass or their blends as feedstock at the same time without modification or adjustment.
摘要: Four thermal dissolution soluble fractions (TDSFs) with different thermal dissolution soluble yields (TDSYs) obtained from thermal and co-thermal dissolutions (CTDs) of a Chinese sub-bituminous Shenfu (SF) coal and lignin were characterized by elemental analysis, FT-IR and synchronous fluorescence spectrum measurements. The hydro-liquefaction properties of the four TDSFs and SF raw coal with and without catalyst were compared and the recycled use property of the catalyst in hydro-liquefaction of the TDSF from CTD of SF coal and lignin was further probed. The results suggests that the TDSF from the thermal dissolution (TD) of SF coal contained much more amount of aromatic components and polyaromatic hydrocarbons (PAHs) with 4 and more rings than those from the CTD of SF coal and lignin at the same temperature. TDSFs gave much higher liquefaction conversions and oil yields than SF raw coal in hydro-liquefaction with or without catalyst. Almost all TDSF was converted with much high yield of oil and the TDSF from CTD of SF coal and lignin gave higher yield of oil than that from the TD of SF coal in hydro-liquefaction with Ni-Mo-S/Al2O3 catalyst which demonstrated a good reusability in the hydro-liquefaction of TDSF from the CTD of SF coal and lignin. Carbon deposition was hardly observed in the 4 times recycle used catalyst.
摘要: A series of H-ZSM-5 zeolites with a silicon to aluminum ratio of 50-4000 but similar crystal size were synthesized and characterized by XRD, N2 sorption, NH3-TPD and Py-FTIR; the intrinsic effect of silicon to aluminum ratio on the selectivity to propene in the conversion of methanol to propene (MTP) was investigated. The results show that a complete conversion of methanol can be initially achieved over H-ZSM-5 with a silicon to aluminum ratio from 50 to 1600 and then the initial conversion of methanol decreases progressively with further increasing the silicon to aluminum ratio. Meanwhile, the selectivity to propene increases monotonically with an increase in the silicon to aluminum ratio of H-ZSM-5 for MTP with a complete methanol conversion, suggesting that a high Si/Al ratio for H-ZSM-5 may enhance the propagation of the alkene-based methylation/cracking cycle relative to the arene-based methylation/dealkylation cycle in MTP. A critical value of acid density, viz., [AS]S, is required to achieve the maximum propene selectivity for MTP with a complete methanol conversion; this critical[AS]S value is 0.175 μmol/m2 for the H-ZSM-5 zeolite under current reaction conditions.