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H. Kubota

Bio: H. Kubota is an academic researcher from Tokyo Institute of Technology. The author has contributed to research in topics: Volume (thermodynamics) & Fluidized bed. The author has an hindex of 2, co-authored 2 publications receiving 20 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the effect of intraparticle temperature distribution on the catalytic effectiveness factor was derived and its magnitude was estimated using an approximate solution, and it was shown that for the several cases examined the term containing effect of temperature is less than 10% of that due to the concentration effect.
Abstract: The effect of intraparticle temperature distribution on the catalytic effectiveness factor is derived, and its magnitude is estimated using an approximate solution. These calculations show that for the several cases examined the term containing the effect of temperature is less than 10% of that due to the concentration effect.

15 citations

Journal ArticleDOI
TL;DR: In this article, a graphical method for determining the process conditions which give the minimum volume of reactor at a given outlet conversion is described, and illustrated by application to a multistage fluidized bed reactor for the catalytic oxidation of sulphur dioxide.
Abstract: A graphical method for determining the process conditions which give the minimum volume of reactor at a given outlet conversion is described, and illustrated by application to a multistage fluidized bed reactor for the catalytic oxidation of sulphur dioxide.

5 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the intrinsic rate equations for steam-methane reforming (RF) and shift (SF) reaction were determined by the calculation of mass and heat balances considering interphase and intraphase diffusions using a numerical solution of the non-linear two-point boundary value problem.

135 citations

Journal ArticleDOI
TL;DR: In this paper, the authors examined the mass transfer limitations of mass transfer in the case of immobilized whole cells for fermentation and showed that they can be used to bring the understanding of heterogeneous catalysis.

126 citations

Journal ArticleDOI
K. Toda1, Makoto Shoda1
TL;DR: Using whole cell invertase of Saccharomyces pastorianus, entrapped in spherical agar pellets, sucrose hydrolysis was carried out in a continuously fed fluidized bed reactor.
Abstract: Using whole cell invertase of Saccharomyces pastorianus, entrapped in spherical agar pellets, sucrose hydrolysis was carried out in a continuously fed fluidized bed reactor. The effective rate of reaction determined experimentally for the catalytic pellet was correlated with particle radius (R), intraparticle concentration of enzyme (Ep) and external concentration of substrate (SR). The results were elucidated by theoretical analysis incorporating internal mass transfer resistance. At high degrees of diffusional resistance, the effectiveness factor was successfully estimted from Bischoff's equation. A dimensionless number, mA R(k2Ep/KmD)0.5(Km/(Km + SR)), was used conveniently to predict the effectiveness factor in those cases wher the intraparticle diffusional effect was less significant. This number was employed to determine critical pellet size for an optimal reaction. The relationship between the properties of the pellet (size and intraparticle enzyme activity) and its apparent kinetic constants (k′2 and K′m), estimated according to Lineweaver-Burk, are discussed.

70 citations

Reference EntryDOI
15 Oct 2011
TL;DR: In this paper, the authors describe the process steps of ammonia production, including feedstock pretreatment and raw gas production, and demonstrate the effect of pressure and other variations of the synthesis loop.
Abstract: The article contains sections titled: 1. Introduction 2. Historical Development 3. Thermodynamic Data 4. Ammonia Synthesis Reaction 4.1. General Aspects 4.2. Catalyst Surface and Reaction Mechanism 4.3. Kinetics 5. Catalysts 5.1. Classical Iron Catalysts 5.1.1. Composition 5.1.2. Particle Size and Shape 5.1.3. Catalyst-Precursor Manufacture 5.1.4. Catalyst Reduction 5.1.5. Catalyst Poisons 5.2. Other Catalysts 5.2.1. General Aspects 5.2.2. Metals with Catalytic Potential 5.2.3. Commercial Ruthenium Catalysts 6. Process Steps of Ammonia Production 6.1. Synthesis Gas Production 6.1.1. Feedstock Pretreatment and Raw Gas Production 6.1.2. Carbon Monoxide Shift Conversion 6.1.3. Gas Purification 6.2. Compression 6.3. Ammonia Synthesis 6.3.1. Synthesis Loop Configurations 6.3.2. Formation of Ammonia in the Converter 6.3.3. Waste-Heat Utilization and Cooling 6.3.4. Ammonia Recovery from the Ammonia Synthesis Loop 6.3.5. Inert-Gas and Purge-Gas Management 6.3.6. Influence of Pressure and Other Variables of the Synthesis Loop 6.3.7. Example of an Industrial Synthesis Loop

61 citations

Journal ArticleDOI
TL;DR: In this article, an overview is given of criteria used to assess mass and heat transfer resistances, parametric sensitivity and runaway in catalytic packed bed (CBS) reactors.

48 citations