Hengfu Shui

The dissolution of lignite in ionic liquids

A Xianfeng lignite (XL) was dissolved in a series of ionic liquids (ILs) at 200 °C. It was found that the anions of the imidazolium-based ILs are one significant factor to affect the extraction yield of XL and the chemical characteristics of extracts obtained from ILs extraction. The dissolution of ILs to lignite is related to the destructive ability of ILs to hydrogen bonds widely existing in lignite. The analyses of residues by in situ diffuse reflectance Fourier transform infrared spectroscopy (DRIFT) indicate that the nature of ILs has a significant effect on the disruption of hydrogen bonds existing in lignite. The effective extraction of lignite results from the fracture of the hydrogen bonding network in lignite during lignite dissolving in ILs. Ionic liquid 1-butyl-3-methyl-imidazolium chloride [Bmim]Cl can dissociate significantly almost all of hydrogen bonds existing in lignite.

High temperature thermal extraction of xianfeng lignite and FT-IR characterization of its extracts and residues

Abstract High-temperature thermal extraction (TE) of Xianfeng lignite by different solvents was carried out, and FT-IR spectra of extracts and residues were determined. The results indicate that Xianfeng lignite shows the macro-molecular network structure by chemical bond cross-linking, in which some low molecular compounds are associated by non-covalent bond interaction. The TE can distinctly increase the extraction yields, which are up to 20.7% and 21.3% at 300°C in toluene and tetralin, respectively. The extracts result from the release of low molecular compounds by thermal rupture of non-covalent bonds at high temperature. Meanwhile, there is no obviously pyrolysis in the process of thermal extraction at 300°C. So the hydrogen donor solvent and hydrogen bond solvent can not increase the thermal extraction yield. The thermal extracts of Xianfeng lignite contain a great of aliphatic alkyl and carbonyl ester, a little of hydroxyl and aromatic structure. The solvent of thermal extraction shows distinctly influences on the constitution and structure of extracts.

Co-liquefaction properties of Shenfu coal and rice straw

Abstract The co-pyrolysis and co-liquefaction behaviors of Shenfu coal (SC) and rice straw (RS) were investigated. The synergistic interaction between SC and RS was examined by comparing the pyrolysis and liquefaction performances of each material with those of their mixtures. TG analysis suggests that the pyrolysis temperature of RS is low. Pyrolysis of RS can form free radicals at lower temperatures, which can promote the pyrolysis of coal when it is co-pyrolyzed with SC, resulting in larger weight losses of their mixture compared to the arithmetic mean values from individual pyrolysis of SC and RS. Co-liquefaction results indicate that there exists an obvious synergistic effect between SC and RS, which is depend on liquefaction conditions. At high liquefaction temperatures and for long reaction time, the synergistic effect decreases because of the increased pyrolysis rate and lack of hydrogen donating ability, resulting in the increased retrogressive condensation reactions. The largest synergistic effect of SC and RS is obtained at 400°C and 60 min with 50% blending of RS. The liquefaction conversion, 14.8%, and hexane soluble fraction, 9.7%, of the co-liquefaction at this optimal condition are higher than the corresponding arithmetic mean values from the individual liquefaction of SC and RS, respectively.

Study on the direct liquefaction reactivity of Shenhua coal catalyzed by SO42–/ZrO2 solid acid

Abstract Effects of liquefaction conditions, including temperature, time, initial hydrogen pressure, and catalyst dosage on direct liquefaction were investigated by batch hydro-liquefaction of Shenhua coal catalyzed by SO 4 2– /ZrO 2 solid acid. The mechanism and catalysis of Shenhua coal liquefaction catalyzed by SO 4 2– /ZrO 2 solid acid were also discussed by distribution and IR analysis of the products. The results indicate that increase in temperature is favorable for catalytic hydrocracking of coal, an increase in liquefaction conversion, and yields of oil plus gas. Raising the initial hydrogen pressure facilitates coal conversion into asphaltene and preasphaltene, but depresses the formation of oil and gas. The increase of liquefaction time is beneficial to the hydrocracking of preasphaltene with an increase in yields of oil plus gas. SO 4 2– /ZrO 2 solid acid mainly catalyzes the hydrocracking of coal macromolecular structure so that the conversion and yields of oil plus gas increase with increasing catalyst dosage. In addition, the conversion of the oxygen-containing structures such as hydroxyl needs high liquefaction temperature and initial hydrogen pressure.

Study on the thermal extraction of Xianfeng lignite in ionic liquid 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate

Abstract The depolymerization behaviors of Xianfeng lignite (XL) in ionic liquid 1-butyl-3-methyl-imidazolium trifluoromethanesulfonate ([Bmim]OTf) was studied in this paper. Also, the thermal extracts and residues obtained from thermal depolymerization of XL at different extraction conditions were analyzed. It was found that [Bmim]OTf had good performance in the depolymerization of XL when the extraction was carried out at 280°C for 4 h with [Bmim]OTf/XL at 3.5. The extraction yield of XL with [Bmim]OTf defined as tetrahydrofuran solubles (THFS) reached to 20.1%. The depolymerization of XL with [Bmim]OTf was promoted markedly with the addition of tetralin (THN), H 2 and ZnCl 2 catalyst, and the yield of THFS reached to 30.0%, 36.9% and 46.8%, respectively. The results showed that the amount of hydrogen bonds in thermal extracts increased significantly with the addition of THN. The contents of aromatics and aliphatic hydrocarbon were enhanced greatly under the existence of H 2 and ZnCl 2 .

Highly dispersed Ni/SBA-15 catalysts prepared with different nickel salts as nickel precursors: Effects of activation atmospheres

Abstract With nickel nitrate and nickel acetate as nickel precursors, a series of Ni/SBA-15 catalysts were prepared by using the impregnation method and activating in air or hydrogen atmosphere. The Ni/SBA-15 catalysts were characterized with XRD, H 2 -TPD, N 2 physisorption and online mass spectroscopy. Their catalytic properties were evaluated with hydrogenation of naphthalene as a model reaction. It was shown that activation in hydrogen greatly increased the Ni dispersion and catalytic activity of Ni/SBA-15 prepared with nickel nitrate, while activation in air significantly improved the sample prepared with nickel acetate. In terms of the thermal decomposition products of the catalyst precursors activated in different atmospheres, the affecting mechanism of the activation atmosphere on the Ni/SBA-15 catalysts prepared with different nickel precursors was proposed.

Promotion of Ni/clay catalytic activity for hydrogenation of naphthalene by organic modification of clay

Abstract A Ni/montmorillonite (MMT) catalyst was prepared by an impregnation method using cetyltrimethylammonium bromide (CTAB)-pillared MMT as the supporting matrix and was characterized using infrared spectroscopy, X-ray diffraction, H2 temperature-programmed desorption, N2 adsorption-desorption, and ultraviolet diffuse reflectance spectroscopy. The catalytic activity of the Ni/MMT for the hydrogenation of naphthalene was also evaluated. The results show that the organic modification of MMT greatly improved the Ni dispersion and textural properties of the Ni/MMT catalyst. The as-prepared Ni/MMT catalyst showed high naphthalene conversion (88.2%) in the hydrogenation reaction; this is much higher than those achieved using Ni supported on pristine MMT (13.1%), Al2O3-pillared MMT (24.2%), and SBA-15 (68.2%). As a result of thermal decomposition of CTAB pillars during reduction of the Ni/MMT catalyst, the CTAB pillars mainly play a role in the Ni/MMT catalyst during impregnation. A mechanism for the promotion of the Ni/MMT catalytic activity by organic modification during impregnation is proposed.

Co-thermal dissolution property of Shenfu coal and rice straw

Abstract The co-thermal dissolution (CTD) properties of Shenfu coal (SC) and rice straw (RS) in 1-methylnaphthalene (1-MN) at different temperatures were studied. It is found that RS gives much higher of thermal dissolution yield (TDY), suggesting its high thermal dissolution (TD) activity. But much amount of gas is produced in the TD process of RS, resulting in the low thermal soluble yield (TSY). For the TD of SC, although the TDYs of SC are much lower than those of RS, but the differences between TDY and TSY from the TD of SC are much smaller than those from the TD of RS. CTD of SC and RS shows that there exists synergistic effect which is the function of temperature. At 320 to 340°C the TSYs have positive synergistic effect. The experimental results are larger than corresponding calculated weighted mean values of the individual TD of SC and RS. While at all the TD temperatures studied, TDYs give negative synergistic effect. The largest enhancements in TSY of 7.9% comparing with corresponding calculated weighted mean values of the individual TD of SC and RS are obtained at 320°C. The mechanism of synergistic effect produced in CTD was discussed based on the characterization of TD soluble fractions.

Study on mild hydrogenation of Xianfeng lignite in ionic liquid

Abstract The liquefaction behaviors of Xianfeng lignite (XL) in ionic liquid 1-butyl-3-methyl-imidazolium tetrafluoroborate ([Bmim]BF4) under mild condition −350°C were studied. The effect of catalysts (FeS, ZnCl2, AlCl3 and FeCl3) on the XL liquefaction in [Bmim]BF4 were investigated and the liquefaction products obtained were analyzed by FT-IR spectra. It is found that the XL has a good hyrogenation activity in the presence of [Bmim]BF4, catalysts and tetralin (THN). XL liquefied product yield reaches to about 66.2% and the main liquefaction product is heavy fraction-tetrahydrofuran soluble (THFS) and tetrahydrofuran insoluble/N-methyl-2-pyrrolididinone soluble fractions (NS). The analyses of liquefied product by FT-IR show that the type of catalyst significantly affects the distribution and structure of liquefied product.

Coliquefaction behaviours of Shenhua coal and sawdust catalysed by different catalysts

AbstractColiquefactions of a subbituminous coal and sawdust over four different coal liquefaction catalysts were studied, and the coliquefied products were characterised by elemental analysis, Fourier transform infrared spectroscopy and gel permeation chromatogram measurements. It is found that FeS+S and Co–Mo/Al2O3 catalysts have the highest catalytic activity for the liquefaction of Shenhua coal and sawdust respectively. There exists synergistic effect in the coliquefaction of Shenhua coal and sawdust, and the main synergistic interaction is reflected by the promotion of preasphaltene formation. The catalytic activities of the four catalysts in the coliquefaction are quite different from their catalytic activities in the individual liquefaction of coal and sawdust. FeS gives the lowest catalytic activity for the coal liquefaction among the four catalysts but has the highest promotion to the synergistic effect in conversion in the coliquefaction of Shenhua coal and sawdust. diminishes this synergistic ef...