Abstract: Thermo-gravimetric analysis was employed to study gasification kinetics of three coal direct liquefaction extract residue chars under steam and CO2 atmosphere. Gasification kinetics of liquefaction residue char was compared at the same conditions. It is shown that temperature plays a significant role on residue char gasification. The decreasing degree of order for carbon and increasing pore structure in residue chars due to supercritical solvent extraction improve gasification reactivity of residue chars. Due to the lack of pore structure, the experimental results of residue chars during steam gasification and CO2 gasification can be well described by the chemical reaction control shrinking core model.
Abstract: Briquette was made from a low active pulverized Fujian anthracite with humic acid as binder. The gasification reaction kinetics and characteristics of briquette were compared with those of Fujian anthracite. The steam gasification rate was determined at the temperature of 900~1 150℃ and atmospheric pressure by using the isothermal thermogravimetry. The kinetic parameters of gasification were calculated based on the shrinking-core model (SCM). The data show that the activation energy of briquette is 102.0 kJ/mol, lower than that of Fujian anthracite(122.5 kJ/mol). The carboxyreactivity of briquette is 80.0% at 950℃, while it is only 33.0% for Fujian anthracite granule. The results exhibit that the briquette has a higher gasification reactivity than Fujian anthracite lump, and could be a substitute of high quality lump coal for the industrial fixed bed gasification.
Abstract: Using a resonance agitation reactor the effect of solvent on liquefaction of Chinese Yangcun bituminous coal under H2 or N2 under 7.0 MPa (cold) was studied. The results show that chain hydrocarbon and mono-ring series compounds are not good solvents. For the same series solvents, partly hydrogen aromatic compounds are the best solvents, followed by aromatic compounds with chain and aromatic compounds. Cycloparaffin and phenols are bad solvent. Decalin and methylnaphthalene do not change H2 into active hydrogen because coal conversion is similar under H2 or N2. Tetralin can change H2 into active hydrogen.
Abstract: The pyridine extraction residue from LL 3#vitrain (LLR) was studied by 13C CP/MAS NMR and XPS analysis. 13C NMR tests show the structure characteristics of carbon atom and 12 structure parameters. Aromatic structure units are dominated by anthracene; aliphatic C atoms exist in the side-chain; O atoms exist in the form of -O-, C=O and -OH; N atoms exist in pyridine and pyrrole. Macromolecular structure model of LLR is constructed based on the results of proximate and ultimate analysis. 13C chemical shift of LLR macromolecular structure is calculated by ACD/CNMR predictor, then the structure is corrected according to the calculation results. And finally the macromolecular structure which is consistent with the experimental results is obtained. Molecular mechanics (MM) and molecular dynamics (MD) were adopted to simulate the energy-minimum conformation of LLR model. The results show that the order of main energy for LLR model is van der waals>torsion>angle>bond. The simulation results indicate that the parallel aromatic layer structure occupies a small proportion. Finally, LLR density is 1.22 g/cm3 by enclosing coal model into the periodical boundary condition. Semi-empirical quantum chemistry methods (PM3) simulation indicates that the C-C bonds adjacent to aliphatic side chain C atoms exhibit higher activity. The terminal C atoms are more negatively charged, and therefore prone to undergo oxidation reactions. The aromatic C atoms are characterized by fewer charges and very high stability.
Abstract: The effects of combustion time on the characteristics of mineral distribution and deposition behavior were carried out in a self-designed drop-tube furnace during oat straw combustion. The thermodynamic equilibrium calculations were used to predict the results. Meanwhile, the ashes of different combustion time at 850℃ were analyzed by XRD, SEM/EDS and EPMA. The results show that the initiative formations of oat straw deposition are alkali metal species which can cohere with fuels, then form particles with different sizes. Holes can be formed in these particles surface by internal oxidation reaction. It is found that potassium feldspar is the main species which acts as an important role in cementing action and supporting structure. There are many K and Al species enriched in the initial deposition. In addition, Na can promote the activity of K in some degree. Some K and Na species in the deposition volatilizes into the gas-phase gradually as the combustion time extends. The relevant compounds of Fe, Ca and Mg continue to fill the interspaces and make the structure closed-grain further. Finally, most elements are distributed uniformity in the deposition.
Abstract: Hydrogen donor visbreaking and conventional visbreaking processes of vacuum residue of Venezuelan synthetic crude oil were investigated in an autoclave. Phase changes of the two reaction systems were observed by a microscope during the thermal conversion. The stabilities of two kinds of visbroken oil were characterized and their SARA group compositions were analyzed. The results show that amorphous micro-particles’ formation, growth and aggregation can be observed clearly by the microscope with the increasing of time at 425℃. Resins and asphaltenes contents in two visbroken oils are both decrease. Compared to conventional visbreaking process, hydrogen donor in hydrogen donor visbreaking process can inhibit the growth of amorphous micro-particles to postpone the phase separation. Moreover, hydrogen donor can inhibit the coke formation and improve the stability of visbroken oil.
Abstract: Selective oxidation of glycerol (GLY) to dihydroxyacetone (DHA) was studied over Bi-Pt/H-mordenite catalyst. The results indicated that the surface area has little effect on the performance of the supported catalysts. H-mordenite as support inhibits the cracking of GLY and thus promotes the selectivity to DHA. Protic solvents such as ethanol and water favor the formation of DNA from GLY. Over the Bi-Pt/H-mordenite catalyst of optimum composition (1% Bi and 5% Pt by weight) and under the optimum reaction conditions (353 K, reaction time of 2~4 h, air flow rate of 20 mL/min, and GLY concentration of 10%), the conversion of GLY and selectivity to DHA reach 70.6% and 61.0%, respectively.
Abstract: A series of starch-modified SiO2 (SSi-T) were obtained by calcining the extrudate of SiO2 and starch at different temperatures (T) and used as the support to prepare Cu catalysts (Cu/SSi-T, 10%) by the impregnation method. The Cu catalysts were characterized by N2 sorption, FT-IR, TG, XRD, SEM and H2-TPR; their catalytic performance in methanol conversion was investigated in a fixed bed reactor. The results indicated that starch can reduce the removal rate of silanol groups (Si-OH) from the surface of the support during calcination and the surface silanol groups are beneficial to the dispersion of Cu species. The calcination temperature of starch-modified SiO2 exhibits a significant influence on the surface silanol (Si-OH) concentration, the surface area and porous structure of the support; as a result, it may be used to adjust the size of supported CuO crystal grains and dispersion of Cu species, which determine the performance of the silica supported Cu catalysts in methanol conversion.
Abstract: The effect of ZrO2, Ru and/or Pt promoters on the structure and performance of Co/Al2O3 catalysts for Fischer-Tropsch synthesis in a slurry reactor was investigated. The results indicated that ZrO2 modification may prevent or reduce the formation of CoAl2O4 phase on the catalysts and improve the reduction of cobalt species, which is beneficial to the increase of the catalytic activity, the decrease of methane selectivity, as well as the improvement of C5+ selectivity. Small amounts of ruthenium and platinum as promoter are able to lower the reduction temperatures of cobalt species (Co3O4→CoO and CoO→Co0) and to get a high reduction extent; as a result, the catalysts promoted with noble metals exhibit much higher activity in CO hydrogenation. Moreover, the impregnation sequence of various components also has an important influence on the performance of resultant catalysts in Fischer-Tropsch synthesis. Impregnation of γ-Al2O3 with Zr at first, the formation of irreducible cobalt aluminate can be prevented; co-impregnation of γ-Al2O3 with Co and Ru can enhance the interaction between cobalt and ruthenium, which benefits to the reduction of cobalt oxides; sequential impregnation of γ-Al2O3 with Co and Pt is beneficial to the dispersion of cobalt species. As a result, the sequentially impregnated catalyst Co-Pt-ZrO2/Al2O3 performs excellently in the Fischer-Tropsch synthesis.
Abstract: The physical structure, microstructure and carbonaceous deposition of Cu/ZrO2 catalysts for methanol synthesis from CO2 hydrogenation were characterized by nitrogen sorption, X-ray diffraction (XRD), transmission electron microscope (TEM), and thermogravimetry and differential scanning calorimetry (TG-DSC) techniques. The results showed that the sintering of active components is the major factor for catalyst deactivation and the carbonaceous deposition is in the next place; the surface area has little effect on catalyst activation.
Abstract: Pd-SO42-/ZrO2-WO3 solid superacid catalysts were prepared and characterized by XRD, FT-IR, TPR, XPS, BET and TG-DTA; the effect of Pd content on its catalytic performance in n-pentane isomerization was investigated. The results showed that Pd can reduce the reduction temperature, increase the decomposition temperature of SO42- and therefore improve the thermostability of the Pd-SO42-/ZrO2-WO3 catalysts. Pd-SO42-/ZrO2-WO3 with a Pd mass fraction of 0.05% exhibits the highest catalytic activity for isomerization; over it under 260℃, 2.0 MPa, mass hourly space velocity of 1.0 h-1, and H2/n-pentane molar ration of 4.0, the conversion of n-pentane and the yield of liquid products are 40.1% and 93.9%, respectively.
Abstract: ZSM-22 zeolites with different SiO2/Al2O3 ratio were synthesized under static conditions by using 1,6-diaminohexane and 1-ethylpyridinium bromide as template, respectively.The structure and acidic properties were characterized by X-ray diffraction (XRD), X Ray Fluorescence (XRF), N2 adsorption, Scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH3-TPD) and FT-IR spectroscopy of pyridine adsorbed (Py-IR). The 0.5%Pd/ZSM-22 bifunctional catalysts were prepared, and the dispersions of metal Pd over bifunctional catalysts were characterized by H2 chemical adsorption, and their catalytic performance for hydroisomerization of n-decane were investigated in the fixed reactor. The results showed that different templates have great influence on the structure and acidity of ZSM-22 zeolites. ZSM-22 zeolite synthesized with 1,6-diaminohexane as template has smaller crystallite size, and isomerization product has shorter spread distance within the molecular sieve channel. It also has high B acid/L acid ratio, medium acidity, and synergetic effect between metal site and acid site. The conversion and isomerization selectivity of n-decane were high over the bifunctional catalysts Pd/ZSM-22.
Abstract: The fresh and deactivated Selective Catalytic Reduction (SCR) catalysts used in a coal fired power plant were studied in a fixed bed reactor. The physical-chemical properties of the catalysts were characterized by means of SEM-EDX, XRF, XPS, N2 adsorption/desorption, FT-IR, XRD and TG. The results showed that the used catalyst was seriously deactivated. The NOx removal efficiency and the specific surface area of the used catalyst (35.0%, 1.05 m2/g) were obviously less than those of the fresh catalyst (88.2%, 72.50 m2/g). The V5+ content in the deactivated catalyst was increased from 17.4% to 32.2% compared with the fresh one, and large quantities of Al2(SO4)3 can be found over the surface of the deactivated catalyst. The results of SEM and XRD showed that the thermal sintering occurred in the deactivated catalyst. Generally, the V2O5-WO3/TiO2 catalyst deactivation can be interpreted by the valence change of V atoms, thermal sintering and aluminum sulfate formation over catalyst surface.
Abstract: Microwave regeneration of SO2-loaded activated carbon (AC) and its consequent adsorption characteristics were studied. The effects of microwave regeneration on the pore texture and surface chemistry of activated carbon were examined by scanning electron microscopy, low-temperature N2 adsorption, elemental analysis and Boehm titration, and its effect on the adsorption of SO2 contained in flue gas passing over activated carbon was analyzed. The results show that increasing microwave regenerative power produces a narrower SO2 regeneration curve with higher peak concentrations, which aids both the regeneration of activated carbon and recovery of a high concentration of SO2. The carbon pores become elongated during the regeneration process. With increasing microwave power, the micropore specific surface area, volume, and the proportion of surface acidic functional groups all increase, while the surface alkaline functional groups decrease. Incomplete regeneration occurrs at 100 W due to the inhibiting effect of residual H2SO4 on adsorptive capacity. At 200, 300 and 400 W, the adsorptive capacity for SO2 exceeds that of the original AC.
Abstract: A series of Mn/Ti-PILC and Mn-La/Ti-PILC(k=0/1,1/4,1/12 and 1/20)materials were prepared by the method of impregnation. The effects of La doping on Mn/Ti-PILC for low temperature SCR were studied, and also the materials were characterized by BET, H2-TPR, NH3-TPD and XRD. It showed that with the doping of La, the reduction temperature of the catalysts lowered, and the redox abilities of the catalysts enhanced. The weak acid on the material surface increased due to the introduction of La. The doping of La was beneficial to the SCR activity. Mn-La/Ti-PILC (k=1/12) showed the best activity.
Abstract: A series of CoOx-CeOx/ZrO2 catalysts for NO oxidation were prepared by impregnation method and characterized by XRD, BET and H2-TPR. The influence of the support as well as the content of cerium and cobalt on the catalytic performance of CoOx-CeOx/ZrO2 in NO oxidation was investigated. The results indicated that the addition of Ce may improve the adsorption ability of the Co-based catalyst for oxygen and the dispersion of active cobalt species. Compared with CoOx/ZrO2 and CeOx/ZrO2, the CoOx-CeOx/ZrO2 catalysts exhibit higher activity and better resistance against SO2 for NO oxidation at low temperature.
Abstract: MoS2 hydrodesulfurization catalyst was prepared by hydrothermal method. The resulting materials were characterized by BET, XRD, SEM and TEM. The influences of different surfactants on activity of catalyst were studied by measuring the hydrodesulfurization (HDS) of thiophene. The results showed that the catalyst particles with the addition of surfactants were loose, while the catalyst without the addition of surfactant exhibited serious agglomeration phenomenon. The surface area, pore volume, diameter and the number of the stacked layer of the catalysts with the addition of surfactants were much greater than those of catalysts without surfactants. The catalysts with surfactants showed high activity in the HDS of thiophene, the conversion of thiophene could reach to 97.0% at 573 K and 4.0 MPa pressure. Furthermore, the catalyst with the addition of cation surfactants showed the highest activity among these catalysts, and the conversion of thiophene was 99.9%. By comparing the conversion, the reactivity order of the catalysts was: Mo-S-C>Mo-S-S>Mo-S-P>Mo-S-N.
Abstract: Ceria-alumina composite supports were prepared by co-precipitation, impregnation and deposition-precipitation method, respectively. Co-Mo catalysts supported on the composite supports were evaluated for sulfur-resistant methanation and the appropriate content of CeO2 in the composite support was further studied. All the samples were characterized by nitrogen adsorption, X-ray diffraction (XRD) and hydrogen temperature-programmed reduction (H2-TPR). It was found that addition of CeO2 to Al2O3 significantly increased the activity of methanation and 25% CeO2-Al2O3 prepared by deposition-precipitation method had the best sulfur-resistant methanation activity.
Abstract: Series of nanosize gold catalysts supported by three kinds of silica with different structures were prepared by deposition-precipitation.The CO oxidation was utilized as a probe.The impacts of silica on the structure and catalytic activity were characterized by low-temperature N2 adsorption/desoprtion,X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),and transmission electron microscope (TEM).The result turns out that the relationship between the gold nanopaticle size and the support’s structure does exist.The higher surface area and the smaller pore size of the silica support corresponding to a smaller gold nanoparticle size and higher activity of CO oxidation.The total CO conversion under 18 000 mL/(h·gcat) with gas ratio of v(CO)/v(O2)/v(Ar)=1/21/78 is 560 K.
Abstract: Pt/Al2O3 catalysts were prepared by a one step method and the catalytic activity of these catalysts was evaluated by methanol combustion at low temperature. The effects of preparation conditions including the reductant concentration, the surfactant dosage, the surfactant concentration and the calcination temperature were investigated in detail. The results indicated that the catalytic activity was the highest under the conditions of 0.1 mol/L of reductant concentration, 8.53 g/gcat. of surfactant dosage and 600℃ of calcination temperature. The methanol conversion on this kind of catalyst could reach to 52% at 25℃. The modified one step method can improve the catalytic activity further, which could reach up to 84% at 25℃.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
