Applied Petrochemical Research (v.5, #4)
Effect of γ-alumina as active matrix added to HZSM-5 catalyst on the aromatization of methanol by Chen Chen; Hongqiang Ji; Qiang Zhang; Chunyi Li; Honghong Shan (231-243).
HZSM-5-based catalyst is a recognized catalyst which is particularly selective towards the formations of aromatics in the methanol reaction. However, studies on HZSM-5-based catalyst were mainly focused on the addition of metallic or/and nonmetallic element. Quite few studies have reported the effect of active matrix such as γ-alumina on the aromatization of methanol. In this study, γ-alumina was introduced into HZSM-5-based catalyst for the purpose of investigating the effect of γ-alumina in methanol to aromatics reaction. The catalysts were characterized by X-ray diffraction, Temperature-programmed Desorption of NH3 (NH3-TPD), Pyridine adsorption FT-IR diffuse reflection spectroscopy and adsorption–desorption measurements of nitrogen, respectively. Characterizations showed that the introduction of γ-alumina increased the amount of mesopores and acid sites in the catalyst. The experimental mainly includes two parts. Firstly, separate reaction performances over the catalyst with/without γ-alumina and γ-alumina showed that γ-alumina could significantly promote the formations of aromatics. However, γ-alumina alone could merely convert methanol to dimethyl ether with a minor quantity of gaseous hydrocarbons. Acid properties showed that the introduction of γ-alumina increased the percentage of Lewis acid on catalyst surface and enhanced acid strength, as a result, promoted the production of active intermediates which was essential for aromatic formation. The rise of aromatics selectivity might be caused by the combined effect of acid site density and acid strength. Follow-up work was mainly focused on the effect of the loading amount and loading order of the catalyst with γ-alumina. Results indicated that the total aromatic yield increased gradually with the increasing amount of catalyst with γ-alumina regardless of the loading order of the catalyst with γ-alumina. Gasoline compositions showed that the increased aromatics were at the expense of paraffins, olefins, and naphthenes. Besides, all single aromatic hydrocarbons increased gradually with the increasing amount of catalyst with γ-alumina. And the aromatics had a larger variation change when methanol first passed through the catalyst with γ-alumina.
Keywords: Methanol; Aromatization; γ-Alumina; Loading amount; Loading order
Preface to the special issue of the “2nd Saudi-Chinese Oil Refinery Forum (SCORF)”: advances in multiple catalytic strategies for producing cleaner fuels and petrochemicals by Zi-Feng Yan; Hamid A. Al-Megren; Rui Feng (245-246).
The preparation of Mg–Al spinels through the method of using templates by Qiang Zhang; Jie Yang; Ya-nan Gao; Chun-yi Li; Li Sun (247-253).
A series of MgO-rich MgAl2O4 samples were prepared by co-precipitation in the presence of CTAB, Triton X-100, and glucose or a combination of CTAB and glucose, which act as templates. The effects of different types and amounts of single template, as well as adding order of the mixed templates, on the specific surface area and particle size were investigated by BET and XRD analyses. The addition of the single template can lead to the increase of the specific surface area, wherein the samples using glucose as templates own the maximum specific surface area of 198 m2/g; as for the use of mixed templates, results revealed that adding CTAB first, followed by the addition of glucose, is better, giving a surface area of 223 m2/g.
Keywords: MgO-rich MgAl2O4 ; Co-precipitation; Templates
Multi-scale CFD simulation of hydrodynamics and cracking reactions in fixed fluidized bed reactors by Jin H. Zhang; Zhen B. Wang; Hui Zhao; Yuan Y. Tian; Hong H. Shan; Chao H. Yang (255-261).
Fixed fluidized bed reactor is widely used to evaluate the crackability of heavy oils and the activity of catalysts. To understand the hydrodynamics, reaction kinetics and thermodynamics in conventional and modified fixed fluidized bed reactors, the computational fluid dynamics method, energy-minimization multi-scale-based two-fluid model coupled with a six-lump kinetic model was used to investigate the gas–solid flow and cracking reactions. The gas mixing and particle volume fraction distributions, as well as product yields in the conventional and modified fixed fluidized bed reactors were analyzed. The residence time distribution model was utilized to obtain the parameters indicating the back-mixing degree, such as mean residence time and dimensionless variance of the gas. The results showed that the simulated product distribution is in reasonable agreement with the experimental data; the modified fixed fluidized bed reactor is closer to the ideal plug flow reactor, which can efficiently enhance the gas–solid mixing, reduce the gas back-mixing degree, and hence improve the reaction performance.
Keywords: Multi-scale structure; Simulation; Catalytic cracking; Reaction kinetics; Fixed fluidized bed reactor
Preparation and catalytic performance of high dispersion of Y zeolite treated with alkali solution by Zhaoyong Liu; Zhongdong Zhang; Jianing Zhai; Pusheng Liu; Chaohe Yang (263-267).
Y zeolite slurry contains a lot of colloid and pretreatment of Y zeolite slurry could separate Y zeolite nanoparticles and Si sol effectively by alkali solution. These nanoparticles were characterized by scanning electron microcopy, particle size distribution, X-ray diffraction, thermogravimetric analysis, and NH3 temperature program desorption. After integrating the Y zeolite in fluid catalytic cracking catalyst, performance of the catalyst containing this nano-zeolite was evaluated by cracking the mixed feed of Xinjiang vacuum gas oil and vacuum resin in fixed-fluidized-bed reactor. This catalyst is favorable for the production of light oil by catalytic cracking the mixed feed.
Keywords: Y zeolite; High dispersion; Modified; Catalytic performance
Domestic technology developments on high-efficiency heavy oil conversion FCC catalysts’ industrialization by Zhaoyong Liu; Zhongdong Zhang; Chaohe Yang; Xionghou Gao (269-275).
The article introduces industrialization status of the following products developed by Lanzhou Petrochemical Company, CNPC: olefin reduction catalyst (LBO and LDO series) and LBO-A additive; propylene maximizing catalyst (LCC-1) and additive LCC-A; heavy oil conversion FCC catalyst LHO-1 and LB series; high octane number FCC catalyst (LOG and LDC series). When LBO-12 catalyst reach 66 % of the system inventory, the gasoline olefin yield decreases 9.1 %; When LBO-16 catalyst reach 50 % of the system inventory, the gasoline olefin yield decreases by 10 %; LBO-16 catalyst’s application shows that the diesel yield maintains the same. When LBO-A reaches 15 % of system inventory, the gasoline RON has increased by 0.6 units and gasoline olefin yield decreased by 3.3 %. The standardization on LDO-75 catalyst after its system inventory reaches 80 % shows that the light oil yield and total liquid yield have increased 1.37 and 0.54 %, respectively; After adopting LCC-2 catalyst and compared to 0 % case scenario, the propylene yield increases by 1.01 %. When LCC-A reaches 6 % of system inventory, the propylene yield increases by 1.41 % and RON by 1.5 units; the total liquid yield increases by 1.44 % and slurry yield drops by 1.41 % after LHO-1 catalyst reaches 80 % of system inventory; LDC-200 catalyst’s application shows 1.77 % total liquid yield increase, 0.83 % light oil yield increase and 1.72 % increase on propylene selectivity. The gasoline RON also increases 1.5 units; by adopting TMP technology and its matching catalyst LCC-300, propylene yield in product distribution reached as high as 20.38 %; When MIP process matching catalyst LIP-100’s system inventory reached 100 %, LPG’s yield increased by 1.04 %, gasoline yield increased by 0.74 %; The comparison of results between end-term and blank case standardization of MIP-CGP process matching catalyst LDR-100 shows 0.4 wt% increase in diesel yield, 3.52 wt% increase in LPG yield and 1.3 units on gasoline RON.
Keywords: Catalytic cracking; Catalyst; Additives; Gasoline olefin; Propylene; Heavy oil conversion; Matching technologies
Effect of magnesium modification over H-ZSM-5 in methanol to propylene reaction by Chen Chen; Qiang Zhang; Zhe Meng; Chunyi Li; Honghong Shan (277-284).
H-ZSM-5-based catalyst is a recognized catalyst which is particularly selective towards the formations of light olefins in the methanol reaction. A series of H-ZSM-5 (SiO2/Al2O3 = 38) modified with different amounts of magnesium have been investigated. All the samples were characterized by X-ray diffraction instrument (XRD), temperature-programmed desorption of NH3 (NH3-TPD) and Fourier Transform Infrared Spectoscopy (FT-IR). The results indicated that the impregnation of H-ZSM-5 (SiO2/Al2O3 = 38) zeolite with various magnesium loading amount significantly affected the strength of acid sites and decreased the concentration of both weak and strong acid sites. As a result of modification, magnesium mainly interacted with strong Brønsted acid sites, thus generated new medium strong acid sites and enhanced the yield of propylene. The optimum acid property for methanol to propylene (MTP) reaction was gotten over 4.0 Mg-ZSM-5 (4.0 wt% Mg) zeolite catalyst. The maximum yield of propylene was 10.62 wt% over 4.0 Mg-ZSM-5 zeolite catalyst by the 30 min on stream. Coke which was mostly formed on strong Brønsted acid sites, would cause the catalysts deactivation, so the reduction of strong Brønsted acid sites could enhance the catalytic stability.
Keywords: ZSM-5; Mg; Modification; Acidity; Deactivation
Retardation effect of nitrogen compounds and condensed aromatics on shale oil catalytic cracking processing and their characterization by Nan Li; Chen Chen; Bin Wang; Shaojie Li; Chaohe Yang; Xiaobo Chen (285-295).
Untreated shale oil, shale oil treated with HCl aqueous solution and shale oil treated with HCl and furfural were used to do comparative experiments in fixed bed reactors. Nitrogen compounds and condensed aromatics extracted by HCl and furfural were characterized by electrospray ionization Fourier transform cyclotron resonance mass spectrometry and gas chromatography and mass spectrometry, respectively. Compared with untreated shale oil, the conversion and yield of liquid products increased considerably after removing basic nitrogen compounds by HCl extraction. Furthermore, after removing nitrogen compounds and condensed aromatics by both HCl and furfural, the conversion and yield of liquid products further increased. In addition, N1 class species are predominant in both basic and non-basic nitrogen compounds, and they are probably indole, carbazole, cycloalkyl-carbazole, pyridine and cycloalkyl-pyridine. As for the condensed aromatics, most of them possess aromatic rings with two to three rings and zero to four carbon atom.
Keywords: Shale oil fluid catalytic cracking; Nitrogen compounds and condensed aromatics; Structure characterization
Ten-lump kinetic model for the two-stage riser catalytic cracking for maximizing propylene yield (TMP) process by Yupeng Du; Qi Yang; Chengtao Zhang; Chaohe Yang (297-303).
Modeling Fluid Catalytic Cracking (FCC) riser reactors is of significance to FCC unit control, optimization and failure detection, as well as the development and design of new riser reactors. Under the guidance of catalytic reaction mechanisms and the demands for commercial production, a ten-lump kinetic model was developed for the TMP process in this study. The feedstock and products were divided into ten lumps by reasonably simplifying the reaction network, including heavy oil, diesel oil, gasoline olefins, gasoline aromatics, gasoline saturates, (butane + propane), butylene, propylene, dry gas and coke. Thirty-five sets of model parameters were estimated with the combined simulated annealing method and the damped least square method. The findings indicated that the model could predict the riser key products and their compositions quite well; thereby it could be useful to the production practice for the TMP process.
Keywords: Riser reactor; Propylene; Lumped kinetics model; Parameter estimation
Vacuum ultraviolet photofragmentation of octadecane: photoionization mass spectrometric and theoretical investigation by Jing Xu; Pengpeng Sang; Lianming Zhao; Wenyue Guo; Fei Qi; Wei Xing; Zifeng Yan (305-311).
The photoionization and fragmentation of octadecane were investigated with infrared laser desorption/tunable synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry (IRLD/VUV PIMS) and theoretical calculations. Mass spectra of octadecane were measured at various photon energies. The fragment ions were gradually detected with the increase of photon energy. The main fragment ions were assigned to radical ions (C n H 2n+1 + , n = 4–11) and alkene ions (C n H 2n + , n = 5–10). The ionization energy of the precursor and appearance energy of ionic fragments were obtained by measuring the photoionization efficiency spectrum. Possible formation pathways of the fragment ions were discussed with the help of density functional theory calculations.
Keywords: Synchrotron vacuum ultraviolet; Photoionization; Alkanes; Mass spectrometry
Preparation and characterization of hierarchical USY by post-treatment by Ke Qiao; Linjiao Wei; Rui Feng; Zifeng Yan; Zhongdong Zhang; Xionghou Gao (313-319).
Two modifying agents, citric acid and EDTA-2Na, were used to modify USY zeolite to obtain the hierarchical USY with high crystallinity. XRD, N2 isothermal sorption, 27Al and 29Si NMR, and TEM were adopted to characterize the dealumination process in the post-treatment of USY. The results showed that all modified USY have increased surface areas and pore volume due to the removal of non-framework Al species. Besides, framework dealumination occurred in the modification process. USY-EC, which was modified by the combined effects of citric acid and EDTA-2Na, has the highest SiO2/Al2O3 ratio of 19.40 and relatively high crystallinity.
Keywords: USY zeolite; Mesopore; Crystallinity; EDTA-2Na; Citric acid
Synthesis of vanadium-based catalysts and their excellent catalytic behaviors on dehydrogenation of C4 hydrocarbons by Ke Qiao; Peng Peng; Chao Hu; Peng Bai; Zifeng Yan (321-327).
In this paper, vanadium-based catalysts made from commercial γ-alumina (V1 series) and from pseudo-boehmite (V2 series) were, respectively, prepared via impregnation method. The samples were characterized and evaluated by various characterization techniques (e.g. X-ray diffraction, N2 adsorption–desorption isotherms, ammonia temperature programmed desorption, and hydrogenation temperature programmed reduction) and dehydrogenation reactions, respectively. The results reveal that the most suitable loading amount of the V1 series of vanadium-based catalysts is 12 % and it is superior to the C4 olefin selectivity. On the other hand, the most suitable loading amount of V2 series of vanadium-based catalysts is 15 %, and this optimal catalyst has better dehydrogenation activity. The two series of samples are mainly composed of weak acid sites and V2 series of vanadium-based catalysts have larger specific surface area, larger pore volume, wider pore size, and better active component dispersion.
Keywords: Dehydrogenation; Vanadium-based catalysts; γ-Alumina pseudo-boehmite
Ni catalysts with different promoters supported on zeolite for dry reforming of methane by Raja Alotaibi; Feraih Alenazey; Faisal Alotaibi; Nini Wei; Ahmed Al-Fatesh; Anis Fakeeha (329-337).
Dry reforming of methane (DRM) is considered a high endothermic reaction with operating temperatures between 700 and 1000 °C to achieve high equilibrium conversion of CH4 and CO2 to the syngas (H2 and CO). The conventional catalysts used for DRM are Ni-based catalysts. However, many of these catalysts suffer from the short longevity due to carbon deposition. This study aims to evaluate the effect of La and Ca as promoters for Ni-based catalysts supported on two different zeolite supports, ZL (A) (BET surface area = 925 m2/g, SiO2/Al2O3 mol ratio = 5.1), and ZL (B) (BET surface area = 730 m2/g, SiO2/Al2O3 mol ratio = 12), for DRM. The physicochemical properties of the prepared catalysts were characterized with XRD, BET, TEM and TGA. These catalysts were tested for DRM in a microtubular reactor at reaction conditions of 700 °C. The catalyst activity results show that the catalysts Ni/ZL (B) and Ca-Ni/ZL (B) give the highest methane conversion (60 %) with less time on stream stability compared with promoted Ni on ZL (A). In contrast, La-containing catalysts, La-Ni/ZL (B), show more time on stream stability with minimum carbon content for the spent catalyst indicating the enhancement of the promoters to the Ni/ZL (A) and (B), but with less catalytic activity performance in terms of methane and carbon dioxide conversions due to rapid catalyst deactivation.
Keywords: Syngas production; Dry reforming of methane; Zeolite supports
Preparation of mesophase pitch by aromatics-rich distillate of naphthenic vacuum gas oil by Ming Li; Dong Liu; Hui Du; Qinyin Li; Xulian Hou; Jiashun Ye (339-346).
Two aromatics-rich distillates R1 and R2 with different properties from naphthenic base vacuum gas oil were used for preparing mesophase pitch through high-pressure thermal treatment. 1H-NMR, FT-IR and VPO were employed to characterize the structural parameters of the raw materials. The products’ optical texture and molecular structure were analyzed by polarized light optical microscopy, 1H-NMR, FT-IR and XRD. The effect of raw materials’ structure on the formation of mesophase pitch was discussed. The results showed that the structure of the raw material had an important effect on the formation of mesophase pitch. The raw material R2 with higher aromaticity, more naphthenic structure and less alkyl side chains was easy to form mesophase pitch with large-domains optical texture, lower softening point and more ordered crystal structure.
Keywords: Mesophase pitch; Naphthenic vacuum gas oil; Optical texture; Molecular structure; Crystal structure
Synthesis of ZSM-5 zeolite from diatomite for fluid catalytic cracking (FCC) application by Yang Li; Hongman Sun; Rui Feng; Youhe Wang; Fazle Subhan; Zifeng Yan; Zhongdong Zhang; Zhaoyong Liu (347-353).
In this study, ZSM-5 zeolite was successfully synthesized hydrothermally from cheap and easily accessible natural mineral diatomite in the presence of tetrapropyl ammonium bromide. The pore structure, acidic sites and surface features of as-synthesized ZSM-5 zeolite were well characterized by X-ray diffraction, scanning electron microscopy, pyridine-adsorbed Fourier transform infrared spectroscopy, and N2 adsorption. The analysis results revealed that the as-synthesized ZSM-5 zeolite exhibited excellent hydrothermal stability, high specific surface area (223 m2 g−1) and more acidic cites than diatomite. After mixing ZSM-5 zeolite with a FCC base catalyst, the catalytic performance was evaluated in a micro-fixed bed reactor using vacuum gas oil (VGO) as feedstock. The high surface area and more acidic sites of as-synthesized ZSM-5 zeolite played an important role in the production of light olefins (propylene and butylene) during catalytic cracking of VGO.
Keywords: Fluid catalytic cracking; ZSM-5 zeolite; Diatomite; Propylene
Desulfurization of Saudi Arabian crudes by oxidation–extraction method by Raja L. AL Otaibi; Dong Liu; Xulian Hou; Linhua Song; Qingyin Li; Mengfei Li; Hamid O. Almigrin; Zifeng Yan (355-362).
The oxidation–extraction desulfurization of Saudi Arabian crudes was conducted with hydrogen peroxide–acetic acid oxidation system. The selection of extractant, the optimization of oxidation–extraction conditions, and the exploration of desulfurization mechanism were studied. As DMF was used as the extractant, the optimal desulfurization rate of 35.11 % and oil recovery of 95 % were obtained at 70 °C with the molar ratio of peracetic acid to sulfur of 8:1, the molar ratio of acetic acid to hydrogen peroxide of 2:1 and the volume ratio of extractant to oil of 1:1. The desulfurization effect of different fractions in the treated Saudi Arabian crudes was found to obey the following order: gasoline–diesel fraction >VGO fraction >VR fraction, due to different types and structures of sulfur compounds. The oil quality was less affected and most sulfides were mainly extracted via DMF.
Keywords: Saudi Arabian crudes; Oxidation–extraction; Desulfurization; Fractions
Hydro-liquefaction of woody biomass for bio-oil in supercritical solvent with [BMIM]Cl/NiCl2 catalyst by Qingyin Li; Peng peng; Dong Liu; Min Li; Linhua Song; Mengfei Li; Zifeng Yan; Yiran Geng (363-369).
Thermochemical liquefaction characteristics of sawdust were explored with ethanol as solvent and [BMIM]Cl–NiCl2 as catalyst. The influences of liquefaction parameters including reaction temperature, residence time and hydrogen initial pressure on the sawdust conversion and products distribution were studied. The maximum bio-oil yield of 75.45 % and conversion of 86.01 % were obtained in ethanol at 320 °C and 30 min under 10 MPa hydrogen pressure. The chemical composition of bio-oil and gaseous products derived from optimized conditions was analyzed via GC–MS and GC. These results showed that the dominant compounds of light oil were carboxylic acid, esters and phenol and its derivatives. In addition, the gaseous components consisted of CO2, CO, methane, ethane and ethene.
Keywords: Sawdust; Bio-oil; Hydro-liquefaction
Pore size-controlled synthesis of molecular sieves and theirs difference in catalytic properties for Fischer–Tropsch synthesis by Min Li; Yue-Lun Wang; Dong Liu; Qing-Yin Li; Xing-Shun Cong; Cui-Yu Sun (371-376).
Three molecular sieves with different pore size distributions, i.e., mesopore (Al-MCM-41), micropore (ZSM-5) and hierarchical pore (HPMS), were synthesized under hydrothermal condition and characterized by N2 adsorption–desorption. Three cobalt-loaded catalysts, i.e., Co/Al-MCM-41, Co/ZSM-5 and Co/HPMS, were prepared by impregnating cobalt nitrate onto three molecular sieves, respectively, and characterized by X-ray diffraction, scanning electron microscopy, and H2 temperature-programmed reduction (H2-TPR). The H2-TPR results show that the reduction temperature of Co/HPMS is lower than those of Co/Al-MCM-41 and Co/ZSM-5, indicating that Co/HPMS has a better catalytic activity. The selectivity of three catalysts for Fischer–Tropsch synthesis was evaluated in a fixed-bed reactor, and the results show that the pore structure is of important influence on the product distribution. Co/HPMS exhibits significantly good selectivity of C5–11 and C12–18 hydrocarbons (up to 25.6 and 27.7 %, respectively), much higher than those of Co/Al-MCM-41 and Co/ZSM-5, due to the confinement effect of micropore and good diffusibility for long-chain hydrocarbons of mesopore in Co/HPMS.
Keywords: Hierarchical porous molecular sieve; Fischer–Tropsch synthesis; Cobalt-based catalyst
Maximizing propylene production via FCC technology by Aaron Akah; Musaed Al-Ghrami (377-392).
This review looks at the main processes available for the production of light olefins with a focus on maximizing the production of propylene. Maximization of propylene production has become the focus of most refineries because it is in high demand and there is a supply shortage from modern steam crackers, which now produce relatively less propylene. The flexibility of the fluid catalytic cracking (FCC) to various reaction conditions makes it possible as one of the means to close the gap between supply and demand. The appropriate modification of the FCC process is accomplished by the synergistic integration of the catalyst, temperature, reaction-residence time, coke make, and hydrocarbon partial pressure. The main constraints for maximum propylene yield are based on having a suitable catalyst, suitable reactor configuration and reaction conditions.
Keywords: FCC technology; Light olefins; Propylene; Catalytic cracking
Mechanistic investigation of methane steam reforming over Ce-promoted Ni/SBA-15 catalyst by Viswanathan Arcotumapathy; Feraih Sh Alenazey; Raja L. Al-Otaibi; Dai-Viet N. Vo; Faisal M. Alotaibi; Adesoji A. Adesina (393-404).
Methane steam reforming experiments were carried out at atmospheric pressure for temperatures between 873 and 1073 K and by varying the partial pressure of methane and steam to achieve S:C between 0.5 and 2.5. Mechanistic considerations for Methane steam reforming (MSR) were derived on the basis of Langmuir–Hinshelwood and Eley–Rideal reaction mechanisms based on single- and dual-site associative and dissociative adsorption of one or both reactants. However, discrimination of these models on statistical and thermodynamic grounds revealed that the model representing a single-site dissociative adsorption of methane and steam most adequately explained the data. However, the product formation rates from these experiments were reasonably captured by power-law model. The parameter estimates from the power-law model revealed an order of 0.94 with respect to methane and −0.16 for steam with activation energy of 49.8 kJ mol−1 for MSR. The negative order with respect to steam for methane consumption was likely due to steam inhibition.
Keywords: Steam reforming; Methane; SBA-15; Nickel catalyst; Ceria-promotion; Kinetic models
Preparation and hydrodesulfurization properties of cobalt–molybdenum–phosphorous catalysts for removal of dibenzothiophene by Xuejin Li; Ke Qiao; Fazle Subhan; Wei Xing; Xinmei Liu; Zifeng Yan (405-411).
In this study, a series of cobalt–molybdenum–phosphorous acid (Co–Mo–P) impregnating solutions with various Co/Mo molar ratios (0.2, 0.25, 0.3, 0.35) were synthesized, and desulfurization catalysts were prepared by mixing the solutions with γ-Al2O3 through an incipient-wetness impregnation method. The Co–Mo–P supported γ-Al2O3 catalysts were tested in the hydrodesulfurization of dibenzothiophene (DBT). The catalysts were characterized by N2 adsorption–desorption isotherms, XRD, py-FT-IR, and HRTEM. Nitrogen adsorption measurements revealed that the as-prepared catalysts possess high specific surface area and appropriate pore size. XRD showed that Co species and Mo species were well dispersed on the surface of γ-Al2O3 with the addition of phosphoric acid. Py-FT-IR showed that the catalyst with a Co/Mo molar ratio of 0.25 exhibited more Lewis and Brønsted acid sites. The stacking number and slab length of MoS2 nanoclusters changed with various Co/Mo molar ratios as revealed by HRTEM. Among the tested catalysts, Co–Mo–P supported γ-Al2O3 with Co/Mo molar ratio of 0.25 exhibited higher activity and selectivity of biphenyl than the other catalysts.
Keywords: CoMoP catalyst; Hydrodesulfurization; Dibenzothiophene
Effect of reaction variables on CO methanation process over NiO–La2O3–MgO/Al2O3 catalyst for coal to synthetic natural gas by Zhong He; Xiaolong Wang; Shiwang Gao; Tiancun Xiao (413-417).
Reaction variables for methanation process were investigated using self-independently developed NiO–La2O3–MgO/Al2O3 catalyst in a big lab scale reactor. The effects of reaction parameters, such as temperature, pressure, H2/CO flow ratio and space velocity on the activity of methanation catalyst were studied. 100 % CO conversion and 95 % of selectivity of methane can be achieved at 400 °C and 3 MPa with the feed ratio of H2/CO as 3.25:1 and space velocity of 12,000 h−1.The optimization reaction parameters were suggested on the basis of this work for the further development and commercialization of methanation catalyst.
Keywords: Methanation; Carbon monoxide; Synthetic natural gas; Catalyst