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Noritatsu Tsubaki - One of the best experts on this subject based on the ideXlab platform.
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Continuous Supercritical Low-temperature Methanol Synthesis with n-Butane as a Supercritical Fluid
Chemistry Letters, 2008Co-Authors: Prasert Reubroycharoen, Yi Zhang, Noritatsu TsubakiAbstract:A process of supercritical low-temperature Methanol Synthesis from syngas containing CO 2 was carried out at 443 K and 60 bar. The 2-butanol and n-butane was used as catalytic solvent and supercritical medium, respectively. The results showed that the total carbon conversion, especially the CO 2 conversion of the Methanol Synthesis was increased significantly under the supercritical condition.
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Methanol Synthesis in inert or catalytic supercritical fluid
Studies in Surface Science and Catalysis, 2007Co-Authors: Prasert Reubroycharoen, Noritatsu TsubakiAbstract:This chapter describes that the low total carbon conversion of the gas-phase reaction results from the highly exothermic reaction from which heat and product cannot be removed rapidly from the catalyst bed. The heat and product removal from the catalyst bed, which would improve the reaction activity, was achieved when SC nhexane was introduced into the reaction. The highest total carbon conversion was obtained by using the alcohols as SC catalytic fluids. SC alcohol improved the conversion by promoting the reaction not only by the supercritical fluid (SCF) advantage, but also by the catalytic effect as behaved in the low temperature Methanol Synthesis. The Methanol Synthesis could significantly be improved by the combination of SCF advantage and catalytic effect when alcohol was used as an SCF. Among alcoholic solvents, 2-propanol exhibited the highest total carbon conversion whereas i-butanol showed the lowest total carbon conversion indicating that the conversion of Methanol Synthesis solely depends on the structure of alcohols. When electronic and spatial factors were balanced, 2- propanol exhibited the highest activity.
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Development of a new low-temperature Methanol Synthesis process
Catalysis Today, 2004Co-Authors: Prasert Reubroycharoen, Tharapong Vitidsant, Yoshiharu Yoneyama, Noritatsu TsubakiAbstract:Abstract A new reaction route of Methanol Synthesis at low temperature from CO2-containing syngas with Cu/ZnO catalyst and the aid of alcohols has been developed in a batch and a flow-type semi-batch reactors. The use of alcohols as catalytic solvents realized Methanol Synthesis at 443 K with formate as an intermediate. The activity of Methanol Synthesis depends on types and structures of alcohols. Among all alcohols, 2-alcohol exhibited the highest activity. With the aid of 2-butanol, the one-pass 47.0% conversion and 98.9% selectivity were achieved at a mild condition, 443 K and 50 bar. The new reaction route of Methanol Synthesis is a practical method for near future technology.
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A New Method of Low-Temperature Methanol Synthesis
Journal of Catalysis, 2001Co-Authors: Noritatsu Tsubaki, Motoaki Ito, Kaoru FujimotoAbstract:Low temperature Methanol Synthesis is a promising technique for the practical Methanol industry. New developments of a new kind of low temperature Methanol Synthesis were reviewed, including the effects of feed gas, reaction solvent, supercritical media and catalyst modification. The reaction mechanism and kinetics were also summarized primarily. Carbon dioxide played an important role in this new kind of low temperature Methanol Synthesis. It reacted with hydrogen adsorbed on catalyst surface to form HCOOM, an important reaction intermediate. Alcohol solvent in the low temperature Methanol Synthesis performed not only a media, but also a homogeneous catalyst. The reaction of the adsorbed formate species with alcohol on Cu/ZnO catalyst surface proceeded according to the Rideal mechanism rather than Langmuir–Hinshelwood mechanism to form alkyl formate. The formation of alkyl formate from alcohol solvent and hydrogenation of such an alkyl formate were the key steps in low temperature Methanol Synthesis reaction. These results provided new insights into low temperature Methanol Synthesis.
Prasert Reubroycharoen - One of the best experts on this subject based on the ideXlab platform.
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Continuous Supercritical Low-temperature Methanol Synthesis with n-Butane as a Supercritical Fluid
Chemistry Letters, 2008Co-Authors: Prasert Reubroycharoen, Yi Zhang, Noritatsu TsubakiAbstract:A process of supercritical low-temperature Methanol Synthesis from syngas containing CO 2 was carried out at 443 K and 60 bar. The 2-butanol and n-butane was used as catalytic solvent and supercritical medium, respectively. The results showed that the total carbon conversion, especially the CO 2 conversion of the Methanol Synthesis was increased significantly under the supercritical condition.
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Methanol Synthesis in inert or catalytic supercritical fluid
Studies in Surface Science and Catalysis, 2007Co-Authors: Prasert Reubroycharoen, Noritatsu TsubakiAbstract:This chapter describes that the low total carbon conversion of the gas-phase reaction results from the highly exothermic reaction from which heat and product cannot be removed rapidly from the catalyst bed. The heat and product removal from the catalyst bed, which would improve the reaction activity, was achieved when SC nhexane was introduced into the reaction. The highest total carbon conversion was obtained by using the alcohols as SC catalytic fluids. SC alcohol improved the conversion by promoting the reaction not only by the supercritical fluid (SCF) advantage, but also by the catalytic effect as behaved in the low temperature Methanol Synthesis. The Methanol Synthesis could significantly be improved by the combination of SCF advantage and catalytic effect when alcohol was used as an SCF. Among alcoholic solvents, 2-propanol exhibited the highest total carbon conversion whereas i-butanol showed the lowest total carbon conversion indicating that the conversion of Methanol Synthesis solely depends on the structure of alcohols. When electronic and spatial factors were balanced, 2- propanol exhibited the highest activity.
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Development of a new low-temperature Methanol Synthesis process
Catalysis Today, 2004Co-Authors: Prasert Reubroycharoen, Tharapong Vitidsant, Yoshiharu Yoneyama, Noritatsu TsubakiAbstract:Abstract A new reaction route of Methanol Synthesis at low temperature from CO2-containing syngas with Cu/ZnO catalyst and the aid of alcohols has been developed in a batch and a flow-type semi-batch reactors. The use of alcohols as catalytic solvents realized Methanol Synthesis at 443 K with formate as an intermediate. The activity of Methanol Synthesis depends on types and structures of alcohols. Among all alcohols, 2-alcohol exhibited the highest activity. With the aid of 2-butanol, the one-pass 47.0% conversion and 98.9% selectivity were achieved at a mild condition, 443 K and 50 bar. The new reaction route of Methanol Synthesis is a practical method for near future technology.
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Accelerated Methanol Synthesis in catalytically active supercritical fluid
Catalysis Communications, 2003Co-Authors: Prasert ReubroycharoenAbstract:Abstract The conversion of Methanol Synthesis was significantly increased when supercritical 2-butanol was used. According to the property of a supercritical fluid, which facilitates heat and product removal, supercritical 2-butanol conventionally promoted the conversion of the Methanol Synthesis from syngas. Furthermore, supercritical 2-butanol, used as a solvent, had a catalytic effect accelerating a new reaction route. The combination of supercritical fluid and catalytic solvent effects broke through the thermodynamic limitation of the reaction efficiency.
Bing-chen Zhu - One of the best experts on this subject based on the ideXlab platform.
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Study of supercritical three-phase Methanol Synthesis with n-hexane at supercritical state
Chemical Engineering Science, 2006Co-Authors: Shu-hua Zhang, Li Tao, Bing-chen ZhuAbstract:Abstract A process of supercritical three-phase Methanol Synthesis on a Cu-based catalyst C302-2, which has high activity at low temperature and low pressure, has been carried out in a mechanically agitated slurry reactor with paraffin as the inert liquid medium and n-hexane as the supercritical medium. The reaction conditions are as follows: pressure ranging from 6.0 to 7.0 MPa , temperature ranging from 235 to 260 ∘ C and mass space velocity from 450 to 1600 L ( STP ) kg - 1 h - 1 . The influences of these conditions on the conversion of CO and the outlet Methanol mole fraction have been investigated in detail. The results show that both the conversion of CO and outlet Methanol mole fraction decreased when the mass space velocity and the temperature were increased under the condition of supercritical n-hexane. In addition, we compared the three-phase slurry bed Methanol Synthesis with and without supercritical medium. The results show that the conversion of CO, CO2 and H2 as well as outlet Methanol mole fraction of supercritical three-phase Methanol Synthesis are obviously higher than those chemical equilibrium values of gas–solid reaction under the corresponding experimental condition. That is to say, the process of supercritical three-phase Methanol Synthesis with n-hexane at supercritical state can remove the limitation of chemical reaction balance of the reversible exothermic Methanol Synthesis reaction on the conversion of reactants by introducing a supercritical medium that plays an important role in the reaction–separation coupling process in Methanol Synthesis, by which the conversion of reactants and outlet Methanol mole fraction at supercritical condition are increased greatly. Therefore, they are higher than those of three-phase Methanol Synthesis without supercritical n-hexane. The advantage of supercritical three-phase Methanol Synthesis is self-evident. Our present study provides an experimental foundation for further engineering exploitation research on the three-phase Methanol Synthesis process with supercritical medium in three-phase slurry reactors.
G. I. Lin - One of the best experts on this subject based on the ideXlab platform.
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Fundamentals of Methanol Synthesis and Decomposition
Topics in Catalysis, 2003Co-Authors: Alexander Ya. Rozovskii, G. I. LinAbstract:Fundamental studies of Methanol Synthesis and decomposition (mainly over Cu-based catalysts) have been carried out. Various kinetic approaches, i.e. TPD study after various chemical treatments of catalyst, non-steady-state transformation of strongly adsorbed species, tracer technique, and steady-state kinetics, have been used. The macroscopic mechanism and detailed reaction scheme of Methanol Synthesis, as well as the kinetic description of the process have been established and proven. Methanol Synthesis over Cu-based catalysts was found to occur by CO2 hydrogenation only, which was coupled with the water-gas shift reaction.
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Mechanism and kinetics of Methanol Synthesis coupled with water-gas shift reaction
Kinetics and Catalysis, 1998Co-Authors: G. I. Lin, K. P. Kotyaev, A. Ya. RozovskiiAbstract:The experimental data are reported on the kinetics of Methanol Synthesis and water-gas shift reaction. Under certain conditions of Methanol Synthesis, some anomalous kinetics was observed: an increase in the average rate of the reaction in the integral flow-type reactor with an increase in the contact time. This unusual behavior is stipulated by the coupling of Methanol Synthesis with the water-gas shift reaction. A modified scheme of the mechanism is proposed that accounts for this coupling.
K.c. Waugh - One of the best experts on this subject based on the ideXlab platform.
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On the mechanism of Methanol Synthesis and the water-gas shift reaction on ZnO
Catalysis Letters, 2006Co-Authors: J. Tabatabaei, B.h. Sakakini, K.c. WaughAbstract:Zinc oxide catalyses both Methanol Synthesis and the forward and ‘everse water-gas shift reaction (f- and r- WGSR). Copper also catalyses both reactions, but at lower temperatures than ZnO. Presently the combination of Cu and ZnO stabilized by Al2O3 is the preferred catalyst for Methanol Synthesis and for the f- and r- WGSR. On Cu, the mechanism of Methanol Synthesis is by hydrogenation of an adsorbed bidentate formate [1] (the most stable adsorbed species in Methanol Synthesis), while the f- and r- WGSR proceeds by a redox mechanism. The f-WGSR proceeds by H2O oxidizing the Cu and CO, reducing the adsorbed oxide and the r-WGSR proceeds by CO2 oxidising the Cu and H2, reducing it [2–5]. Here we show that the mechanisms of both reactions are subtly different on ZnO. While Methanol is shown to be formed on ZnO through a formate intermediate, it is a monodentate formate species which is the intermediate; the f- and r-WGS reactions also proceed through a formate – a bidentate formate - in sharp contrast to the mechanism on Cu.