Abstract: The floated coal samples with different ash contents were obtained by coal washing, and the effect of ash content on addition of fluxing CaCO3 was investigated. The results show that silica content and silicon to aluminum ratio (Si/Al) of ash decrease with decreasing ash content. The AFTs of coal ashes change with increasing CaCO3 addition. The additive CaCO3 content is closely related to the mineral formed at high temperatures and their contents. Furthermore, for the FH and SH coals after floatation, the viscosity of slag with CaCO3 addition exhibits a behavior of glass slag, and also has a large slagging temperature range. The properties of the floated coal ash slags with CaCO3 addition well meet the requirement of slag tapping in entrained flow gasifier. It is an effective way for Shanxi high ash content and ash fusion temperature coals to combine coal washing and CaCO3 adding to adjust the ash flow properties in entrained flow gasification.
Abstract: The combustion of Shengli lignite demineralized with hydrochloric acid was carried and residues from different reaction conditions were obtained. The microstructural properties of the lignite and residues were examined by FT-IR, XRD, XPS and Raman, respectively. The results indicate that aliphatic functional groups were consumed during combustion, while oxygen-containing groups and aromatic structure were consumed and generated alternatively. The proportion of C-C/C-H structure decreased after increasing, while the content of carbon-oxygen structure was increased following decrease. The aromaticity of residues increased and ID/IG increased before decrease, while IS/IG decreased before increase. This indicated that graphitization transformation degree of lignite obviously increased during combustion, especially in the late stage of reaction.
Abstract: Effect of demineralization on minerals and organic structure of Huadian oil shale treated by HCl and HF/HCl sequentially was examined using FT-IR and XRD technology. The results show that HCl/HF treatment can effectively remove minerals except pyrite, but HCl can damage the space frame structure of kaolinite. Organic matter structure with the form of disordered amorphous polymers are mainly composed of aliphatic structure in lower metamorphic grade. Acid treatment effect on shale organic macromolecular structure is very low, but has certain influence on the organic structure. HCl treatment mainly influences oxygen containing functional group and benzene ring structure, generates a large amount of carboxylic acid and destroys the polycyclic structure of benzene ring, but has less effect on aliphatic compounds. HF treatment main affects aliphatic compounds, it can destroy the fat chain bridge bond structure fracture, makes fat chain length shorter and decreases content of aliphatics in the samples. Both HF and HCl treatment can destroy the hydroxyl groups of shale, especially for the associated hydroxyl hydrogen bond.
Abstract: The supported NiO-Fe2O3/Palygorskite and Gamma Alumina(NiO-Fe2O3/PG-γ-Al2O3) catalysts were prepared by deposition-precipitation and homogeneous-precipitation methods using PG-γ-Al2O3 as a carrier, and different approaches including EDX, XRD, SEM and N2 isothermal adsorption-desorption were used to characterize the synthetic catalysts. Meanwhile, the catalytic pyrolysis of biomass straw was conducted to test the catalytic activity, the regenerative service life and the anti-carbon capacity of NiO-Fe2O3/PG-γ-Al2O3 catalyst in a tube furnace, and to compare with the catalytic properties of single carrier catalysts. The results indicate that the prepared PG-γ-Al2O3 carriers have a high specific surface area of 134.21 m2/g and the average pore size is 39.65 nm. The active components are loaded uniformly and in a good dispersion over NiO-Fe2O3/PG-γ-Al2O3 catalyst, meanwhile, the Ni-Fe alloy and the nickel-aluminum spinel structure exist simultaneously in the catalyst. The catalytic activity testing shows that the NiO-Fe2O3/PG-γ-Al2O3 catalysts have a very high catalytic activity in pyrolysis of biomass straw. It could obviously improve the quality of the gas such as the content of H2 and CO and the calorific value. The catalytic activity, regeneration effect and anti-carbon deposition ability of NiO-Fe2O3/PG catalyst are better than that with single carrier catalyst.
Abstract: To study influence of oxygen on distribution and transformation of fuel-N, pyrolysis experiments of straw were conducted in a two stage fixed bed reactor simulating the run conditions of grate firing. The conversion pathway of fuel-N was depicted by studying types and content of N-containing compounds in tar by GC-MS, and effect of oxygen was analyzed. Compared with inert atmosphere, tar and char yields decrease with introduction of oxygen, which leads to a decrease of N-distribution in tar and char and increase in gas fractions. Protein and amino acids are the main N-containing components in fuel, which initially go through a series of primary reactions, producing primary tar components like amides and amines. Then the primary tar goes through secondary reactions to yield secondary tar components including nitriles and N-heterocyclic compounds. In the presence of oxygen, content of primary tar components like amides and amines decrease significantly, and secondary tar components like nitriles and N-heterocyclic compounds increase.
Abstract: Imidazolium perrhenate was applied as the catalyst to promote the degradation of microcrystalline cellulose (MCC) with the solvent of ionic liquid 1-allyl-3-methyl imidazolium chloride ([Amim]Cl). The effects of reaction temperature, reaction time, reactant concentration, the amount and structure of catalyst on the degradation of cellulose were studied in details. When using 5% of [mim-(CH2)3SO3H]ReO4, 70μL of water, 0.1g cellulose and 2.0g [Amim]Cl under microwave irradiation for 30min at 160℃, 89.6% of total reducing sugar (TRS) and 46.7% of glucose yield can be obtained. The degradation mechanism of cellulose catalyzed by imidazolium perrhenate was also studied.The hydrogen bonding between hydroxyl groups of cellulose and ReO4 anion and aromatic ring cation of catalyst is assumed to be the key step for depolymerization of cellulose.
Abstract: HZSM-5 zeolites with SiO2/Al2O3 molar ratio of 50 as the raw material were treated by a certain concentration of NaOH and then impregnated with citric acid solution to prepare microporous and mesoporous hierarchical HZSM-5 catalyst. The catalytic performance of the prepared catalysts for thiophene alkylation reaction was investigated using simulated oil. The results show that the residual impurities in the pores after alkali treatment can be eliminated by acid washing with citric acid solution. When the concentration of the citric acid solution is 0.5 mol/L, the HZ(AC-0.5) catalyst has the appropriate pore size and acidity, so the conversion of thiophene alkylation is the highest, which is up to 95.6%. The performance of thiophene alkylation reaction was also investigated by respectively using dibenzothiophene thiophene derivatives as model compounds, olefin isoprene as model compounds, aromatic benzene as model compound on the HZ (AC-0.5) catalyst. And then we analyzed the influence of different components in the simulated oil on the conversion and selectivity of thiophene alkylation reaction. It has been demonstrated that the optimum reaction temperature of thiophene alkylation reaction is 120℃. At the optimum temperature, the conversion of benothiophene alkylation is higher than that of thiophene alkylation. The conversion of thiophene will be increased when the olefin isoprene is used as model compound. The conversion of thiophene will be decreased when benzene is used as aromatic model compound.
Abstract: Samples of Cu (Ⅰ) Y, NiY and CeY were prepared by modifying a NaY type zeolite with a liquid ion-exchange method and characterized by means of XRD, ICP-MS, pyridine Py-FTIR, NH3-TPD and low temperature N2 adsorption-desorption.Use of micro coulombmeter WK-2D, sulfide luminescence detecting chromatography GC-SCD and fixed bed technology to evaluate the desulfurization performance of the samples for a 300 μg/g sulfur content model oil (dipropyl sulfide, cyclohexanol mercaptan and 1-heptyl mercaptan are prepared with nonane, etc.) and a hydrodesulfurization (HDS) gasoline. Results show that Cu (Ⅰ) Y has good adsorption desulfurization performance on those different oils. In the liquid ion-exchange process, the modified Y zeolite's surface acidity has greatly changed. The strong surface Bronsted (B) acidity of modified Y zeolite has negative effects on adsorption desulfurization through catalyzing mercaptan and thioether to form bigger molecules, which cover the surface of Y zeolite and block the adsorption activity sites, resulting in lower sulfur adsorption capacity of the catalyst. The weak surface Lewis (L) acidity has positive effects on adsorption desulfurization.
Abstract: The stability and catalytic activity of Au10, Au13 and Au20 clusters in water gas shift reaction (WGSR) were investigated by density functional theory (DFT); the adsorption behavior of reaction species and the reaction mechanism of WGSR on various Aun clusters were explored. The results indicated that the stability of three Aun clusters follows the order Au10 < Au13 < Au20, whereas their electron delocalization and adsorption capacity decreases in the sequence of Au13 > Au10 > Au20. Three Aun clusters exhibit the same rate-determining step for WGSR, i.e. H2O dissociation; however, they are quite different in the actual reaction routes. Over Au10 cluster, the WGSR reaction follows the carboxyl mechanism, characterized by the direct dissociation of COOH*; over Au13 cluster, the redox mechanism applies, suggested by the disproportionation of two OH*; over Au20 cluster, the WGSR reaction proceeds via the carboxyl mechanism, represented by the disproportionation of COOH* and OH*. A comparison for the optimal reaction paths over three Aun clusters suggests that the Au13 cluster has the highest catalytic activity in the WGSR reaction at low temperature.
Abstract: Cu-Al spinel catalysts were synthesized by the solid-state reaction method using pseudo-boehmite as the Al source and hydroxides, acetates and nitrates of copper as the Cu source. Several techniques such as TG-MS, XRD, H2-TPR, BET and XANES were employed for the exploration of the synthetic process, phase composition, reduction behaviors and surface structure of the catalysts. Moreover, the catalytic properties for methanol steam reforming (MSR) of these catalysts were evaluated. The obtained results showed that spinel solid solution can be successfully synthesized with the three different Cu sources. The synthesized spinels showed little difference in crystalline size, but their specific surface area (25.4-65.9 m2/g), pore volume (0.213-0.434 cm3/g), surface structure (distribution of Cu) and reduction properties were quite different, which led to different catalytic behavior and performance. During the methanol steam reforming reaction, active Cu species can be released from Cu-Al spinel structure. The catalyst synthesized from copper(Ⅱ) hydroxide shows excellent catalytic performance for MSR as it generates the smallest Cu particles (6.6 nm).
Abstract: A series of K promoted K/MgFeAl-HTLcs catalysts with different Mg/Fe/Al molar ratios were prepared by means of coprecipitation and impregnation method for direct synthesis of light olefins from CO hydrogenation. The samples were characterized by XRD, N2 adsorption-desorption, SEM, TG, H2-TPR and XPS measurements. The results show that MgFeAl-HTLcs catalyst precursors has typical layered structure. MgO, Fe2O3 and small amount of MgFeAlO4 are formed after calcination. MgCO3 and Fe3O4 could be observed after reaction, and a little Fe5C2 iron carbide with broad and weak peaks appear simultaneously. Thermal stability of K/MgFeAl-HTLcs is improved due to recovery of hydrotalcite-like structure after K promotion. With increase of Al content, specific surface area of the precursors decreases monotonically after structure reconstruction. Reduction of Fe2O3 to Fe3O4 is inhibited with addition of Al, compared with K/Mg-Fe sample. Fe enrichment before reaction and K enrichment after reaction are observed on secondary calcination samples. During CO hydrogenation, the prepared samples show high activity and C2-4= selectivity with low C5+ weight fraction. C5+ hydrocarbons decrease and olefin selectivity increases with increasing Fe/Al molar ratio. The C5+ decreases from 22.17% to 10.90%, and C2-4= weight content increases from 40.98% to 47.28% on K/1.5Mg-0.67Fe-0.33Al sample compared with that of K/1.5Mg-0.67Fe sample.
Abstract: Iron based catalysts supported on aluminum pillared clays (Fe/Al-PILC) was prepared by impregnation method and the selective catalytic reduction of NO with propene by the Fe/Al-PILC catalysts was investigated in a fixed bed reactor. The physical and chemical properties of the catalysts were characterized by N2 adsorption/desorption, XRD, H2-TPR, Uv-vis, Py-FTIR, etc. Results showed that 9% Fe/Al-PILC reduced more than 98% of NO at 400-550℃. SO2 and water vapor slightly influenced the catalytic activity of the catalysts. XRD and N2 adsorption/desorption characterization results revealed that the iron oxides in the catalyst were highly dispersed on the surface of the carrier, and the catalyst has a large specific surface area and pore volume. H2-TPR results indicated that the activity of the catalysts was mainly determined by the reduction performance of Fe2O3 phase. Uv-vis results showed that the activity of the catalysts was positively correlated with the iron oxide oligomer FexOy. Py-FTIR results indicated that both Lewis acid and Brønsted acid were formed on the catalyst surface and the Lewis acid sites were the main catalytic activity center of NO and C3H6 reaction.
Abstract: A series low temperature SCR catalysts Mn0.4Ce0.07Hox/TiO2 catalysts with different Ho doping ratios were prepared by impregnation method. The effects of Ho doping on the denitrification of Mn-Ce/TiO2 low temperature SCR catalyst were studied. The catalysts were characterized by using X-ray photoelectron spectroscopy (XPS), X-ray fluorescence probe (XRF), Brunauer-Emmett-Teller (BET) surface measurement, X-ray diffraction (XRD) and NH3-temperature programmed desorption (NH3-TPD). The results showed that the doping of Ho can improve the low temperature denitrification performance of Mn-Ce/TiO2 catalyst. The catalytic efficiency of Mn0.4Ce0.07Ho0.1/TiO2 with the ratio of Ho:Ti=0.1 reached 91.17% at 200℃, which is the highest during the process. The catalytic efficiency could reach more than 80% at 140-240℃. The characterization results showed that Ho doping can increase the surface area of the catalyst, increase the concentration of chemisorbed oxygen in the catalyst and increase the deposition amount of Ce on the catalyst surface.
Abstract: A layer of manganese dioxide/poly (p-phenylenediamine) (PoPD) complex was coated on the surface of polyphenylene sulfide (PPS). First, the o-phenylenediamine (OPD) monomer was uniformly adsorbed on the surface of the PPS fiber by the effect of π-π conjugation. Then, the o-phenylenediamine was oxidized by the potassium permanganate solution to produce poly (p-phenylenediamine) coat, while the potassium permanganate was reduced to MnO2 catalyst and inserted into the poly (o-phenylenediamine) matrix. The MnO2 catalyst was firmly bonded with the PPS filter because the MnO2/PoPD complex formed by in-situ polymerization exhibited a strong bond with the PPS filter. The preparation method of MnO2/PoPD@PPS composite filter was simple. Due to the mild experimental conditions, the performance of the PPS filter media was not damaged. The structure and properties of MnO2/PoPD@PPS composite filter were studied in detail by FESEM, XPS, XRD, FT-IR and denitrification test. The results of denitration test show that the denitrification rate of MnO2/PoPD@PPS composite filter increases with the increase of KMnO4/PPS mass ratio. The optimum denitrification rate is 36%-94% at 80-180℃ with the KMnO4/PPS mass ratio of 1:1, and it is 88% at 160℃ after 10 h catalyst stability test. The XPS spectrum of Mn 2p proves that the catalyst on the composite filter is MnO2 that possesses amorphous structure observed from XRD patterns. It can be observed from the FESEM diagram that the dispersion of the MnO2 catalyst on the PPS filter is uniform.
Abstract: BiOI/BiOCl composite photocatalysts with oxygen vacancy (OV) were successfully synthesized by solvothermal method with bamboo charcoal (BC) as the carrier. The effect of temperature and light on the catalytic performance in the removal of NOx was considered and the photocatalytic reaction mechanism was investigated with the assistance of SEM, XPS, XRD, PL and Uv-vis analysis. The results indicated that optimum denitrification efficiency of 73% can be achieved under 30℃ and with a xenon lamp of 500 W. After the modification with the OV agents, the specific surface area and pore capacity of BC were greatly enhanced; the adsorption capacity was also improved and the functional groups of C=O and -COO can be efficiently broken into C-O functional groups. Meanwhile, the modification with OV agents can increase the photocatalytically active sites, reduce the recombination rate of electron hole pairs, and thus improve the efficiency of NO photocatalytic degradation.
Abstract: In this paper, we studied the effects of supports, such as SiO2, MgO, Al2O3 and MgAl2O4, on the performance of supported NiSn catalyst for propane dehydrogenation. NH3 temperature-programmed desorption, H2 temperature-programmed reduction were applied for the characterization of the catalysts. The results show that SiO2 with large specific surface area and large pore size can achieve good contact between catalyst and reactants, leading to a high content of Ni2.67Sn2 alloy and a reduced diffusion resistance, In addition, their weak acid improve dehydrogenation activity and propene selectivity.
Supervisor：Chinese Academy of Sciences
Sponsors by：Shanxi Institute of Coal Chemistry, Chinese Academy of Sciences Chinese Chemical Society
