We studied dehydrogenation catalysts to improve the performance of the ethane cracking tube. Ga, Ge, In, and Sn were studied as dehydrogenation catalysts. Catalytic activity tests showed that the Ga catalyst has the best performance among them. Although the Ga catalyst supported on α-Al2O3 calcined at 1323 K deactivated with time on stream, the Ga catalyst supported on γ-Al2O3 calcined at 1323 K showed high ethylene yield and stability. Analyses of BET, XRD, EDX, and XANES were conducted to elucidate the differences of their performances. Ga catalyst supported on γ-Al2O3 calcined at 1323 K showed high catalytic activity and stability because Ga was supported as a highly dispersed β-Ga2O3-like structure thanks to high specific surface area of the γ-Al2O3 support.
Water-in-crude oil (W/O) emulsions were prepared from two crude oils, Upper Zakum (UZ) and Hout (HT), of which density and API degree were similar. The W/O emulsions were subjected to natural settling test to determine the mass% water resolved and settling model of water particles in W/O emulsions was proposed. Three fractions obtained from the crude oils, asphaltene (APS), i.e., pentane insoluble fraction, deasphalting oil, i.e., pentane soluble fraction containing resin (R), and waxlike oil, i.e., pentane soluble fraction not containing resin, were mixed with liquid paraffin–toluene or toluene to prepare model W/O emulsions. These model emulsions were centrifuged to elucidate factors influencing on the mass% water resolved and the stability of model W/O emulsions. The results of natural settling test showed that the mass% water removed and increase in water particle size in W/O emulsion of HT were higher than those of UZ, suggesting higher stability of W/O emulsion of UZ compared with HT, with respect to coalescence of water particles in W/O emulsions. The results of centrifugation of model W/O emulsions indicated that ASP and R in UZ crude oil and ASP in HT crude oil may act as stabilizers of model W/O emulsions, and suggested capability of ASP and/or R for the stabilization of W/O emulsions through enhancement of oil-water interfacial film strength.
This study focuses on clarifying the active species over a sulfated transition metal oxide (Cr, Mn, Fe, Co, Ni, Cu) catalyst for propane dehydrogenation. The unsulfated catalyst showed a high conversion for the dehydrogenation of propane, with significantly low selectivity to the desired product of propylene. On the other hand, the sulfated catalyst displayed a high selectivity to propylene, though the conversion was slightly decreased. The sulfation treatment was especially effective for the Co and Fe catalysts. The sulfate species (SO42−) were reduced to the active species of the sulfide ion (S2−) in the reaction atmosphere, which increased a selectivity to propylene.
Tri-reforming of methane (a mixed reaction with steam reforming, dry reforming, and partial oxidation of methane) for syngas production is investigated over Ni supported catalysts in an electric field at low temperature of 473 K. The main objective is to gain enthalpy from exhaust gases of automobiles using an exhaust gas recirculation (EGR) system, so high methane conversion and low combustion (oxidation) are anticipated. Ni(ac)/Mg/La0.1Zr0.9O2 catalyst showed high methane conversion with methane combustion suppressed even at 473 K in an electric field. The role of co-supported Mg on Ni/La0.1Zr0.9O2 catalyst was investigated by several characterizations. Mg-addition stabilized the Ni–oxide on Ni(ac)/Mg/La0.1Zr0.9O2 catalyst even in the reaction atmosphere by virtue of the formation of an adjacent structure of Ni and Mg, and it contributed to methane combustion suppression.
The Supercritical Water Cracking (SCWC) process is a partial upgrading process to produce low density and low viscosity crude from extra heavy crude. The SCWC process can convert Canadian oil sand bitumen with API° 8 to distillate products with API° 19-24, which satisfies the Canadian pipeline specifications. The advantages offered by the SCWC process are lower operating expenditure by eliminating diluent costs compared with the conventional dilution method, and the simple configuration without hydrogen and catalyst requirements leading to lower capital expenditure compared with the full upgrading method. The SCWC process was demonstrated with a bench unit (capacity is 0.15 barrel/day) and a pilot unit (5 barrel/day). In this paper, the characteristics and performance of the SCWC process are described, and the anticipated performance of the thermal cracking reaction in a larger scale unit also investigated by comparing conversions and product yields of the bench unit and the pilot unit. Analysis of product stability and long term operation with the pilot unit evaluated the conversion limit in terms of stable operation of the SCWC process in a large scale unit.
Characteristics of CH4 adsorption and CH4 replacement with CO2 in kerogen micropores were investigated by molecular dynamics (MD) simulations to obtain accurate estimates of CH4 volume and reduction of environmental load by applying multi-stage CO2 fracking for shale gas development. Firstly, CH4 density in the kerogen micropores was found to be about 1.8 times higher than in the mesopores outside the kerogen, indicating that an adsorption model accounting for the micropore filling is essential to correctly evaluate the volume of CH4 adsorption. Secondly, CO2 molecules with linear shape easily passed through the throat of the kerogen micropore, whereas CH4 molecules with regular tetrahedron shape did not. Thirdly, CH4 was easily replaced by CO2 in the kerogen micropores due to the higher affinity for CO2 than CH4 of oxygen atoms, which are much more common than other heteroatoms in the kerogen molecule. Finally, H2O molecules in the kerogen micropores and mesopores were aggregated by hydrogen bonding around the heteroatoms and prevented the replacement of CH4 by blocking the pathways.
Effect of Al cocatalyst in ethylene polymerization using (imido)vanadium(V) complexes containing anionic N-heterocyclic carbenes with a weakly coordinating borate moiety in 4-position (WCA-NHC), [V(N-2,6-Me2C6H3)Cl2(WCA-NHC)] [1; NHC=1,3-bis(2,6-dimethylphenyl)-imidazolin-2-ylidene], have been explored. The activities by 1 upon presence of AliBu3 in ethylene polymerization and in the copolymerization with norbornene (NBE) were higher than those in the presence of MAO, and the resultant poly(ethylene-co-NBE)s prepared by 1-AliBu3 catalyst possessed uniform molecular weight distributions and compositions. Formation of vanadium(III) species could be assumed upon presence of AliBu3, especially on the basis of both NMR and ESR spectra (silent) and certain significant changes in the V K-edge XANES (pre-edge and edge region) spectrum, whereas no significant changes in the XANES spectrum were observed from the toluene solution containing 1 upon addition of MAO. It is thus suggested that a difference in the catalyst performances between in the presence of MAO and AliBu3 should be due to a formation of different catalytically active species with different oxidation states.
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