Abstract: The pyrolysis experiments of oil shale from Liushuhe were performed by using an autoclave with saturated or unsaturated water. The formation mechanism of pyrolysate including retorting gas, oil and bitumen was discussed. It is found that the free radical and carbocation reactions occur simultanously during oil shale pyrolysis. The physical and chemical properties of water at high pressure and temperature are very different from those at normal temperature and pressure, which can promote the carbocation reaction of oil shale as the acid and alkali catalyst. At the same time, the free radical reaction also occurs because of the diversity in chemical bonds of oil shale.
Abstract: Geochemistry of lanthanides in late Paleozoic coal from Weibei were studied by means of mathematical statistics methods. It was discovered that not only REE chondrite-normolized in any geological changed with their +3 ionic radius, but also the ratio of REE among the different geological changed with their ionic radius. It is another manifestations of “the effect on geochemistry of Lanthanides” found. According to this effect, the migration, distribution and enrichment between different coal or other geological could be comparative discussed qualitatively, and it may become a new manner to study geochemical tracer of REE.
Abstract: The main properties of products from real biomass (water hyacinth, rice straw), and biomass model compounds (microcrystalline cellulose, xylan) by hydrothermal liquefaction (300℃ for 30min) and carbonation (220℃for 4h) were examined in a batch reactor. The results showed that rice straw (RS) has the highest heavy oil yield of 21.62% from the hydrothermal liquefaction (HTL). The oil yields from HTL are 15.00%, 11.61% and 12.19% for microcrystalline cellulose (MC), xylan (XL) and water hyacinth (WH), respectively. The yields and composition of the heavy oil depend on the chemical ingredients in real biomass. The major compounds of the liquid products from HTL were identified by TOC and GC-MS. The heavy oil mainly contains ketones, phenols, aldehydes, alcohols, and a few acids from different materials. The hydro-char, analyzed by SEM and TEM, is composed of carbon micro-spheres in the form of core-shell during HTC. MC, WH, and RS have higher char yield. Finally, the formation of carbon micro-spheres of the xylan was proposed.
Abstract: Esterification with microwave, as a new method to upgrade crude bio-oil, was brought forward according to the composition characteristics of bio-oil. Crude bio-oil was upgraded in ethanol using the 732# cation exchange resin and ZnCl2 exchanged resin as catalysts and using the microwave as heating resource. The results show that the ZnCl2 exchanged resin performs a higher activity duing the upgrading process and the heating by microwave can effectively promote the upgrading process compared to traditional water-bath heating.The analyzed results by GC-MS show that the components of upgraded bio-oil are optimized greatly. Under the best reaction conditions the acetic acid conversion gets to 70.47% and the adverse components such as acids, ketones, aldehydes and phenols in crude bio-oil are removed during upgrading process. The kinematical viscosity of upgraded bio-oil decreases by 36.29% and the density decreases by 19.4% compared to that of crude bio-oil. While the heating value of upgraded bio-oil increases by 48.43%, which indicate that the quality of upgraded bio-oil is obviously improved.
Abstract: The preparation of biodiesel from pistacia chinensis bunge (PCB) seed oil produced by two-phase solvent extraction (TSE) was studied. The results show that the optimal extraction conditions are 50g samples, ethanol/iso-hexane volume ratio 50∶50 and the total volume of 300mL at 40℃ with duration of 30min. Under these conditions，the extraction rate of PCB seed oil could achieve 99.5%, and the free fatty acid (FFA) and water contents of PCB seed oil are reduced to 0.37% and 0.046%， respectively. This meets the requirement of alkali-catalyzed transesterification. After the TSE process of PCB seed，the investigations were carried out on transesterification of methanol with oil-iso-hexane solution coming from TSE process in the presence of Li2O/MgO as solid base catalyst. The influences of weight ratio of iso-hexane to PCB seed oil，alkali catalyst amount，reaction temperature, molar ratio of methanol to oil and reaction time on PCB seed oil conversion were investigated separately. The fatty acid methyl ester content could achieve 98.1% using 2.0% (catalyst/oil weight ratio) solid base catalyst at 65℃ and 3h，2∶1 weight ratio of iso-hexane/oil and 9∶1 mole ratio of methanol/oil. The fatty acid methyl ester content remains 90% after the solid base catalyst was reused ten times. The results indicates that the catalyst of Li2O/MgO has a higher activity and stability.
Abstract: CuO-ZnO-Al2O3 was modified by co-precipitation, using TiO2 obtained from hydrolyzation of tetra-n-butyl titanate (C16H36O4Ti). The catalytic performances were investigated under the conditions of 260℃, 2.6MPa, H2∶CO2=3∶1 (volume ratio) and SV of 3600mL/(g·h). The modified samples showed a higher performance than CuO-ZnO-Al2O3 and 4% was the optimal dosage. XRD, H2-TPR, H2-TPD, NH3-TPD and CO2-TPD characterizations were performed. TiO2 improved CuO dispersion in the catalyst and enhanced the adsorption/activation of CO2 and H2 on the surface of catalyst, leading to easier reduction of CuO and lower concentration of strong acid sites on the surface of catalyst simultaneously.
Abstract: Polyoxymethylene dimethyl ethers (PODEn or DMMn) were synthesized by the condensation of methanol and trioxymethylene over the catalysts of several molecular sieves like HY, HZSM-5, Hβ and HMCM-22; the effect of their acidic properties on product distribution was investigated. The results indicated that the acidic molecular sieves, especially HMCM-22, are catalytically active for the condensation of methanol and trioxymethylene to form DMMn. Over HY, the main product is dimethoxymethane (DMM), with a selectivity of 92.87%. Over HZSM-5 and Hβ, the main products turn to be DMM1~3 and the yields of DMM3~8, which are ideal additives for diesel fuel, reach 6.40% and 13.78%, respectively. With HMCM-22 as the catalyst, the formation of long chain DMMn products is further enhanced and the yield of DMM3~8 attains 29.39%. The results of NH3-TPD demonstrated that the product distribution is related to the surface acidic properties of the catalyst used; short chain DMM may be primarily formed on weak acidic sites, while the acidic sites of medium strength can enhance the formation of diesel fuel additive components DMM3~8.
Abstract: TiO2-Al2O3 composite supports were prepared by co-precipitation method and characterized by N2 physisorption, X-ray diffraction (XRD) and pyridine adsorption FT-IR spectroscopy. Ni-Mo-S/TiO2-Al2O3 supported catalysts were prepared with in-situ sulfidation method and their hydrodeoxygenation (HDO) properties were tested using phenol as model compound. The effects of aluminum sources and precipitants on the properties of TiO2-Al2O3 composite supports and the effects of support properties on the HDO properties of Ni-Mo-S/TiO2-Al2O3 catalysts were studied. The results showed that the pore volume and average pore diameter of the support prepared using aluminum chloride as aluminum source were as high as 1.12cm3/g and 18.0nm, respectively. The support prepared using aluminum sulfate and ammonium bicarbonate as initial materials had high specific surface area (295m2/g). Among three precipitants, the support precipitated using ammonia solution had the most L-acid sites while the support prepared using aluminum sulfate had a little of B-acid sites. The primary factors of supports which affected the HDO properties of Ni-Mo-S/TiO2-Al2O3 catalysts were the acidity and specific surface area of supports. In the HDO of phenol on Ni-Mo-S/TiO2-Al2O3 catalyst, the conversion, the deoxygenation reaction rate and the total oxygen-free compound were as high as 81.9%, 79.4% and 100%, respectively.
Abstract: The supported tungsten phosphide catalysts with different content of nickle were prepared over MCM-41. The samples were characterized by X-ray diffraction(XRD), BET specific surface area, scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS) methods. The dibenzothiophene(DBT) hydrodesulfurization(HDS) performance of catalysts was evaluated in a fixde-bed reactor at 633K, 3MPa H2 and with a space velocity of 4h-1.The results showed that the addition of Ni promoted the growth of active species WP and increased WP crystal dimension. Some content of nickel was favor to increase the BET specific surface area of catalyst. Ni had positive effects on the DBT HDS reaction of WP/MCM-41 catalysts. WP was the main active phase. The addition of small amount(1%) of nickle was favor to the formation of WP active phase and increased the active site number. The addition of excess content(5%, 9%) of nickel probably conduced the formation of a new active species with similar structure of Ni-W-P, which decreased the proportion of WP active phase on the catalyst surface and resulted in the decline of catalytic activity. Particularly, the catalyst with nickel content of 1% had high HDS activity, giving the DBT desulfurization rate and DBT conversion rate of 76.78% and 72.16%, respectively, which were 30.04% and 21.62% higher than those given by the catalyst without nickel addition. The hydrodesulfurization(HYD) was the dominant path for WP/MCM-41 catalysts in DBT HDS reaction. The HYD selectivity was improved with the increasing of nickel content of catalyst.
Abstract: The effect of metal element (Y, Ga, Cr, Zn and Cu) modification on the hydrothermal stability of Y zeolite was studied by X-ray diffraction (XRD), solid-state NMR spectroscopy (MAS NMR) and scan electron microscopy (SEM). The results showed that the introduction of yttrium element can suppress the condensation of unite cell and the formation of extra-framework alumina and hence remarkably enhance the hydrothermal stability of Y zeolite. The introduction of zinc or copper can also strengthen the stability of Y zeolite to some extent, however, the framework structure of Y zeolite modified by zinc or copper may be destroyed heavily by high temperature (800℃) steam treatment. Unlike yttrium, zinc and copper, gallium or chromium element can not stabilize the structure of Y zeolite, but the hydrothermal stability of Y zeolite modified by gallium or chromium lies between that of Zn/Cu-modified zeolites and that of Y-modified zeolite.
Abstract: This article describes the synthesis and characterization of a novel MCM-41/ZSM-5 composite molecular sieve. The composite was synthesized under hydrothermal conditions by use of cetyltrimethylammonium bromide as the template and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), infrared spectroscopy and N2-sdsorption, respectively. The results indicated that the sample was a composite molecular sieve which was different from ZSM-5 zeolite and MCM-41 sieve. The influence of the synthesis parameters was discussed. It was shown that the gelation time, aged temperature and the quantity of CTAB played an important role in the synthesis.
Abstract: With alkali-treated beta zeolite as the sources of silicon and aluminum and cetyltrimethylammonium bromide (CTAB) as template, mesoporous aluminosilicates with hexagonal structure denoted as B-MCM-41 were synthesized. The structure and acidity of B-MCM-41 were characterized by XRD, N2 adsorption-desorption, FT-IR, 27Al MAS NMR, HRTEM and NH3-TPD. Compared with conventional mesoporous aluminosilicates materials, B-MCM-41 synthesized in this way exhibits enhanced acidity and higher activity for catalytic dealkylation of C+10 aromatic hydrocarbon. B-MCM-41 mesoporous structure may be built in the presence of a cationic surfactant template via the assembly of the dissolved fragments such as five member secondary structural units which are formed from the dissolution of preformed beta zeolite in a caustic solution.
Abstract: CO adsorption, CO dissociation and C－H and C－C bond-making reactions on Cu-covered Fe(100) have been computed within the framework of periodic density functional theory. Compared to the clean Fe(100) surface with strong CO activation, Cu monolayer-covered Fe(100) surface has weaker CO adsorption energy, lower CO activation degree; and ultra higher CO dissociation barrier (2.4eV). Under H co-adsorption, CO dissociation is favored kinetically on Fe(100). On the Cu-monolayer covered Fe(100), co-adsorbed H largely facilitates CO dissociation via the formation of CHO. The energy barrier decreases to as low as 0.92eV. It is also found that C－H and C－C bond-making reactions of Cu monolayer-covered Fe(100) surface have lower activation barriers and are more exothermic than on the clean Fe(100) surface.
Abstract: Two-bubble class model for Fischer-Tropsch synthesis in slurry bubble column has been developed. Three models including two-bubble class model, perfected mixed model and multi-stage series model have been contrasted for Fischer-Tropsch synthesis. The perfected mixed model is the most appropriate in simulation of kinetics for Fischer-Tropsch synthesis. The multi-stage series model can approximately simulate reaction results of Fischer-Tropsch synthesis in slurry bubble column when the series number is appropriate, and it can be used in simulation of the effects of back mixing on reaction behaviors. The two-bubble class model is the best selection to describe the relations between the hydrodynamics and the reactions in slurry bubble column for Fischer-Tropsch synthesis.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
