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In this work, hierarchical ZSM-5 zeolites featured by different Si/Al ratio and mesoporosity were prepared via soft template. The hierarchical zeolites supported iron catalysts were prepared by incipient impregnation and their properties were studied by XRD, XRF, BET, SEM, TEM and NH3-TPD. The resultant catalysts were used to convert syngas into aromatics. The results indicated that zeolite with high acidity could increase the selectivity to aromatics in the oil product. By using low Si/Al ratio catalyst Fe-Z-50-5, 70.7% of selectivity to aromatics can be obtained in oil product. With the increase of mesoporosity, selectivity of C5+ oil product also increased. By adjusting silane addition, 23.2% selectivity of aromatics was obtained in hydrocarbon over Fe-Z-80-15 catalyst, which is the highest among all the same catalyst system under low H2/CO syngas (H2/CO = 1). However, hierarchical zeolite support with different Si/Al ratio and mesoporosity have little effect on the distribution of aromatic product.

In the present study, a novel route of upgrading lignin pyrolysis vapor to aromatic hydrocarbons was investigated. Guaiacol was used as model compound to investigate the coupling conversion of pyrolysis vapor and methanol. Co-feeding methanol obviously facilitated the conversion of guaiacol to aromatic hydrocarbons and inhibited coke formation. HZSM-5, Al-MCM-41 and γ-Al2O3 catalysts were screened, and γ-Al2O3 showed the best catalytic activity for the catalytic co-cracking reaction due to the appropriate acid property. The effects of methanol to guaiacol molar ratio, reaction temperature and W/Fguaiacol on product distribution over γ-Al2O3 were studied in a fixed bed reactor to reveal the reaction mechanism. As hydrogen donor, the co-fed methanol promoted the deoxygenation of guaiacol. The water formed through methanol dehydration was an efficient agent for attenuating coke deposition. The highest yield of aromatic hydrocarbons was 81.2% when the methanol to guaiacol molar ratio was 25 at 400 °C. The investigation of W/Fguaiacol indicated that the synergistic effect of co-feeding was sensitive at lower W/Fguaiacol. Co-feeding methanol with phenol, anisole and the phenolic mixture were also investigated, and high yields of aromatic hydrocarbons were obtained, which demonstrated that co-feeding methanol was a promising process for upgrading complicated pyrolysis products.

Liquid carbon dioxide phase-transition blasting (LCO2-PB) is a promising alternative method for enhanced coalbed methane (ECBM) extraction and prevention of coal and gas outbursts. During the process of the LCO2-PB fracturing the coal seam, the improper application of fracturing model will reduce the efficiency of gas drainage and cause gas disasters. To clearly understand the ECBM modes of LCO2-PB fracturing coal seam process, this paper employed experiments to investigate the effect of leakage characteristics of the LCO2-PB on fracture models of coal cubes, including release pressure (Pr), filling level (V), release diameter (Dr) and blasting hole diameter (Db). We propose the combination I and II of the LCO2-PB leakage parameters and applied two methods to the in-situ tests. The results revealed that the gas flow of the boreholes of the LCO2-PB with the combination I is 0.368 m3/min, which is 2.07 times that of the combination II (0.178) in the soft coal seam. Besides, the average methane flow of the boreholes with combination II is 0.796 m3/min, which is 1.78 times the combination I (0.448) in the hard coal seam. The adjustment of leakage parameters of the LCO2-PB technology can be helpful for ECBM and reduce the risk of coal and gas outbursts in the soft and hard coal bed.

Heavy fraction of bio-oil, the bottom-layer of biomass fast pyrolysis oil, is hard to be directly used due to its high molecular weight, complex components and deteriorate thermal stability. Here, a novel catalytic hydrotreating process for the heavy fraction of bio-oil, including depolymerization, decarboxylation, decarbonylation, hydrogenation and hydrodeoxygenation (HDO), is proposed with Ru/α-Al 2 O 3 catalyst and super/subcritical ethanol. Results demonstrated that heavy fraction of bio-oil was depolymerized into monomeric phenolic compounds, and then was converted to hydrocarbons by hydrodeoxygenation in one-pot. The average molecular weight (M w ) of upgraded oil decreased drastically from 8941 g/mol to 937 g/mol during the catalytic hydrotreating process, and the formation of coke is suppressed. Under the optimal conditions, the total yield of hydrocarbons, which were comprised of alkyl-substituted cyclohexane and alkyl-substituted benzene, could be up to 23.15%. These hydrocarbons have a high octane number, would be the desirable components for fungible liquid transportation fuel. Furthermore, Ru/α-Al 2 O 3 catalyst can be regenerated by calcination in the presence of O 2 . These results indicated high quality fuels could be obtained from heavy fraction of bio-oil over suitable catalytic system.

Enhanced coalbed methane (ECBM) recovery by liquid carbon dioxide phase-transition blasting (LCO2-PB) has been considered as a viable methane recovery. However, the shock of the boiling liquid expanding vapor explosion (BLEVE) of CO2 during the fracturing process is still not clear, hindering the application of technology. In this paper, the pressure and temperature of LCO2-PB were characterized through a controlled BLEVE experiment using a cylindrical section. Three parameters were controlled during the experiments: the fill pressure, the blasting pressure and the release orifice on the tube. The results indicated that the maximum crushed radius of LCO2-PB occurred at the combination of parameters with the highest blasting pressure, medium filling level and maximum release orifice. The peak overpressure and the distance formed were increasing as the burst pressure increased and the filling pressure reduced respectively. The quasi-static effect increases with the increase of the blasting pressure and the reduction of the release orifice. The laboratory and field results all suggest that the action form of cracked coal can be controlled by adjusting initial parameters, which ensuring the extraction concentration and utilization rate, and reducing the natural emission of methane and greenhouse gas emissions.

To improve the quality of fast pyrolysis bio-oil, an efficient catalytic upgrading process is proposed with pristine Ni/MgO catalyst and ethanol. Esterification, hydrogenation, alkylation of aromatic ring and depolymerization of lignin-derived pyrolytic oligomers simultaneously occurred in the upgrading process. Esters, ketones and alkyl-substituted aromatic compounds were found to be the main components in the volatile fraction of the upgraded bio-oil. Under the optimal conditions, pH value and HHV (high heating value) of the upgraded bio-oil were 5.01 and 24.9 MJ kg −1 , respectively. This result suggested that the properties of bio-oil could be effectively improved by the catalytic upgrading process. Moreover, carbon efficiency of this upgrading process was relatively high because that formation of coke is suppressed in the upgrading process.

Experiments on the reactivity and structural changes of asphaltene in the SCW upgrading process were conducted with a batch reactor. The reactivity and structural changes of asphaltene was evaluated with the yield of products (gas, maltene and coke) and the characterizations of remaining asphaltene with elemental analysis (C, H, N, and S), gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR). As shown from the transformation of asphaltene, the enhance of severity condition would increase the conversion of asphaltene but resulted in the secondary reaction of maltene and the formation of more coke and gases. And the characterizations fully illustrated that the size was greatly reduced, the ratios of H/C, N/C and S/C were seriously lowered, the alkyl side chains were much shorted and the aromaticity and condensation degree were significantly enhanced as for remaining asphaltene obtained from the SCW upgrading process. Finally, the transformation pathway of asphaltene was analyzed with the reconstruction of asphaltene macromolecular model at various severity condition and the results showed that the reactivity and structural changes of asphaltene was closely related to the cracking of asphaltene macromolecular into smaller one, the fracture of alkyl side chains and the reaction of dehydrogenation and polymerization.

National Natural Science Foundation of China [51076157]; National 863 Plan [2010AA101606]; Chinese Academy of Sciences [KSCX2-YW-G-063]