Effect of La2O3／γ—Al2O3 Catalyst on the Activation of CH4 and CO2 to C2 Hydrocarbons under Non—equilibrium Plasma

In the reaction of methane and carbon dioxide to C2 hydrocabons under non-equilibrium plasma, methane conversion was decreased,but selectivity of C2 hydroxarbons was increased when using La2O3/γ-Al2O3 as catalyst. So the yield of C2 hydrocarbons was higher than using plasma alone. The synergism of La2O3/γ-Al2O3 and plasma gave methane conversion of 24.9% and C2 yield of 18.1%. The distribution of C2 hydrocarbons changed when Pd-La2O3/γ-Al2O3 was used as catalyst,the major C2 product was ethylene.     

The Effect of CaAl_2O_4 Spinel on Ni/Al_2O_3 Catalyst for CH_4/O_2-to-Syngas Reaction

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Effect of CeO_2 Promoter on the Performance of Catalyst for CH_4, CO_2with O_2 to Synthesis Gas

Inrecentyears,thereactionofmethane,carbondioxidewithoxygentosynthesisgashasbeenreceivingmore.attentionfromthevieWPointofPrpservingglobalenvironment,becauseCH#andCO,areofgreenhousegasesandtheircontributiontoglobalwarmingisverylargeowingtotheirhugeamountreleasedintheatmosphere'.Inaddition,therearetwoadvantagesinthisprocessobviously,bychangingtheratiooffeed,itcanachievethermalneutralizingandtheCO/H,ratiocanlbebovariedintherangeof0.5~ltofitdifferentindustrialrequirement.Therearehardlyanypapers…     

XPS/AES Characterizations of Active Surface Carbon Species for CO Generation on Co/Al_2O_3 Catalyst for CH_4/CO_2 Reforming to Syngas

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Studies on the Reaction Mechanism of CO_2-Reforming of Methane over Co/γ-Al_2O_3 Catalyst

l.IntroductionTheC02-ref0ndngofCfyconvertSbothC02andCH4(greenhousegases)tousefulfeedstock(Syngas)witi1H2/C0rati00flfl'whichissujtablef0rsomeSPeCialchendtalprocesses'e.g.,oxompthesis[']IthasbeenusedinconJunchonwiththewidelyaPPliedboCH4refonningwhentheHz/C0molarratiooftheproductgasisrequlredtobelessthanthatgeneratedbySteaInrefondnga-lone.Interestjng1}-.tbjspr0cesseambitScertainP0tenhalt0beusedasthermocliendcalheaTipef0rrecoven'.st0rageandtra-nsnussionofsolarandotherrenewableenergysourc…     

抗积炭CH_4/CO_2重整用Ni/Al_2O_3催化剂

甲烷转化制备的合成气是合成液体燃料和含氧有机化合物的原料 .甲烷转化制合成气的方法有甲烷蒸汽重整、甲烷部分氧化和甲烷、二氧化碳重整 3种 [1～ 3] .对于 CH4/CO2 重整反应 ,调节进料比可制备出 H2 /CO≤ 1、富含 CO的合成气 ,它适于羰基合成和 F- T合成 .这种方法一方面充分利用碳资源 ,缓解能源危机 ;一方面可减少温室气体的排放 ,改善人类的居住环境 .目前倍受关注 .CH4/CO2 重整制合成气 ,Rh、Ru、Pd、Ir等贵金属有很高的活性和稳定性 [4] .但其价格昂贵 ,高温易流失 ,商业化困难 .Ni基催化剂的活性与贵金属相当 ,但它易积…     

Effect of Titanium on Methanol Synthesis from CO_2 Hydrogenation over Cu/γ-Al_2O_3

Conversion of CO_2 to useful chemicals is widely investigated by many workers from the view point of finding technologies for suppressing the green house effect caused by CO_2 emission. The utilization of industrial Cu/ZnO/Al_2O_3 catalyst, which exhibited a high activity for methanol synthesis from syngas, was not successful1 in CO_2 hydrogenation. Therefore, it is important to synthesize and develop new catalysts with a higher activity and better selectivity to methanol. Recently, great …     

Effect of Reaction Temperature and Pressure on the Metathesis Reaction between Ethene and 2-Butene to Propene on the WO3/Al2O3-HY Catalyst

Effect of reaction temperature and pressure on the metathesis reaction between ethene and 2-butene to propene was studied on the WO3/γ-Al2O3-HY catalyst. The activity is found to increase with elevated temperature and reaches a plateau at 150-240℃. After that, the activity undergoes a remarkable decrement at too high temperature. The effect of temperature is elucidated by the oxidation state of tungsten species. The evaluation results also indicate that the stability is dependent on this reaction parameter. Medium pressure (0.5-0.8 MPa) is favorable for stability, while atmospheric pressure or too high pressure (>1.0 MPa) deteriorates the stability. For explanation, UV Vis, FT-IR, O2-TPO, and TG techniques are used to characterize the spent catalysts.     

CH_4 reforming with CO_2 for syngas production over La_2O_3 promoted Ni catalysts supported on mesoporous nanostructured γ-Al_2O_3

Nanostructured γ-Al2O3 with high surface area and mesoporous structure was synthesized by sol-gel method and employed as catalyst support for nickel catalysts in methane reforming with carbon dioxide. The prepared samples were characterized by XRD, N2adsorption-desorption,TPR, TPO, TPH, NH3-TPD and SEM techniques. The BET analysis showed a high surface area of 204 m2 g-1and a narrow pore-size distribution centered at a diameter of 5.5 nm for catalyst support. The BET results revealed that addition of lanthanum oxide to aluminum oxide decreased the specific surface area. In addition, TPR results showed that addition of lanthanum oxide increased the reducibility of nickel catalyst. The catalytic evaluation results showed an increase in methane conversion with increasing lanthanum oxide to 3 mol% and further increase in lanthanum content decreased the catalytic activity. TPO analysis revealed that the coke deposition decreased with increasing lanthanum oxide to 3 mol%. SEM and TPH analyses confirmed the formation of whisker type carbon over the spent catalysts. Addition of steam and O2 to dry reforming feed increased the methane conversion and led to carbon free operation in combined processes.     

Cofeeding of Methane and Ethane to Produce Syngas over a LiLaNiO/γ-Al_2O_3 Catalyst

There are abundant supplies of mixture gases containing CH, and C,H, from natural gas,FCC (Fluidized Catalytic Cracking) dry gas, refinery gas, elc. Commonly, the amount ofC,H, is relatively lower than that of CH,. With regard to the utilization of methane,partial oxidation of methane to syngas over nickel based catalysts has received intensiveallention l'2. For mixture gases containing CH# and C,H,, their conversion to syngas isalso of significance (but has not gained adequate attentio…     

Studies on the Structure and Properties of Multiphase Al_2O_3 Abrasion-resistant Ceramics

1 INTRODUCTION Due to its high intensity, high hardness, high tem- perature resistance, corrosion resistance and abra- sion resistance, Al2O3 abrasion-resistant ceramic is widely applied in many fields, such as metallurgy, minerals, electric power, building materials and che- mical engineering as grinding medium in the ball grinder. The properties of Al2O3 ceramic are positi- vely correlated to its purity: the higher the purity is, the better the properties of the product are, but cor- r…     

Kinetics of the Oxidative Dehydrogenation of Isobutane over Cr_2O_3/La_2(CO_3)_3

The oxidative dehydrogenation (ODH) of isobutane over Cr2O3/La2(CO3)3 has been investigated in a low-pressure Knudsen cell reactor, under conditions where the kinetics of the primary reaction steps can be accurately determined. By heating the catalyst at a constant rate from 150-300℃, temperature fluctuations due to non-equilibrium adsorption are minimized. The evolved gas profiles show that ODH to isobutene and water is a primary reaction pathway, while carbon dioxide, which forms from the catalyst during reaction, is the only other product. This CO2 evolution may enhance the activity of the catalyst. Isobutene formation proceeds with the participation of lattice oxygen from the Cr2O3/La2(CO3)3 catalyst. The intrinsic Arrhenius rate constant for the ODH of isobutane isk(s-1) = 1011.5±2.2exp{-((55±5) -ΔHads kJmol-1)/RT}The small pre-exponential factor is expected for a concerted mechanism and for such a catalyst with a small surface area and limited porosity.     

Characterization of various surface Co-sites on reduced Co-Mo/Al_2O_3 and Ru-Co-Mo/Al_2O_3 catalysts using IR and MS spectroscopies

An investigation on adsorption of NO on reduced Co-Mo/Al_2O_3 and Ru-Co-Mo/Al_2O_3catalysts has been performed using FT-IR and MS spectroscopies. IR spectra of NO adsorptionshowed two bands at 1895 and 1800 cm_(-1), and NO--TPD profiles gave rise to several peaks at 353, 423and 473 K, which are assigned to various Co-sites on the surface. Compared with Co-Mo/Al_2O_3,the adsorption rate, binding energy, and amount of NO adsorbed on Ru-Co-Mo/Al_2O_3 are veryhigh.     

Theoretical studies of adsorption property on Ir_4/MgO and Ir_4/γ-Al_2O_3

The adsorption properties of atomic and molecular species on Ir4/MgO and Ir4/γ-Al2O3 have been systematically studied by means of planewave density functional theory(DFT)calculations using the periodic boundary conditions.The binding energies of these species were ordered as follows:H2O相似文献   

Reactions in a Mixture of CH_4 and CO_2 under the Action of Microwave Discharge at Atmospheric Pressure

Reactions between CH_4 and CO_2 under the action of continuous microwave discharge at atmospheric pressure were studied in a special homemade reactor. The main products were CO and H2, while acetylene and ethylene were also found in the products. Experimental results show that conversions of CH4 and CO2 could be higher than 90% without the presence of any catalyst. Effects of CO2/CH4 molar ratio and total flow rate of the feed gas on the reaction were also investigated.     

Effect of H_2S on the transformation of 1-hexene over NiMoS/γ-Al_2O_3 with hydrogen

The effect of H2S contents on the transformation of 1-hexene with hydrogen over NiMoS/γ-Al2O3 catalyst was investigated.Inhibition of H2S on both hydrogenation and isomerization reactions of olefin has been demonstrated.And the promotion effect of H2S on the formation of C6 thiols and C12 thioethers has also been observed.It was found out that there was only one type of active site on the NiMoS/γ-Al2O3 for reactions which include hydrogenation reaction,isomerization reaction and sulfides formation reaction,...     

Effect of Dissolved CO_2 and Tetrahydrofuran on the Polymerization of Acrylic Acid

Recently,c0mpressedgaseshavebeenusedins0megasantisolventprocesses,suchasfractionati0n0fnaturaIproducts,recrystallization0forganicandin0rganicmaterials,andpolymerpr0cessing'2.WestudiedtheeffectofthedissovledsupercriticaICO=andTHFonthep0lymerizati0n0fAA.Itwasn0tfoundintheliterature.ExperimentalOnemlacrylicacidmonomer,O.O20ginitiator2,2'-azobis(is0butyronitrile)(AlBN),anddesiredam0unt0fTHFwereaddedintoanopticalcelloflOml.CO,wascharged,stirreduntilvap0r-liquidequilibriumwasreachedatabout30…     

Adaptation of Cu/ZnO/Al_2O_3 to Temperature Change in Methanol Synthesis from CO_2 Hydrogenation

The induction behavior in CO2 hydrogenation was studied by varying the reaction temperature to investigate the adaptation of the Cu/ZnO/Al2O3 catalyst to the temperature change. The results indicated that a used catalyst had a tendency to keep the last running state in new reaction conditions for MeOH formation, and that this tendency was related to the difference in Cu/Cun+ ratio caused by CO2 and CO produced at different reaction temperatures. However, the reverse water-gas shift reaction (RWGS) induced at four temperatures was completely different from that of methanol synthesis. It implied that the two so-called competitive reactions in CO2+H2, RWGS and methanol synthesis, have different active centers.