CFD modeling of gas flow in porous medium and catalytic coupling reaction from carbon monoxide to diethyl oxalate in fixed-bed reactors

2011 ◽  
Vol 66 (23) ◽  
pp. 6028-6038 ◽  
Author(s):  
Xi Gao ◽  
Ya-Ping Zhu ◽  
Zheng-hong Luo
Keyword(s):  
Carbon Monoxide ◽  
Porous Medium ◽  
Gas Flow ◽  
Fixed Bed ◽  
Coupling Reaction ◽  
Cfd Modeling ◽  
Diethyl Oxalate ◽  
Fixed Bed Reactors

Catalytic Pyrolysis of Palm Empty Fruit Bunch over Activated Natural Dolomite Catalyst: Product Distribution and Product Analysis

2020 ◽  
Vol 991 ◽  
pp. 111-116
Author(s):  
Arif Hidayat ◽  
Muflih Arisa Adnan ◽  
Achmad Chafidz
Keyword(s):  
Gas Flow ◽  
Catalytic Pyrolysis ◽  
Fixed Bed ◽  
Product Distribution ◽  
Product Analysis ◽  
Nitrogen Gas ◽  
Empty Fruit Bunches ◽  
Fixed Bed Reactors ◽  
Bio Oil ◽  
Liquid Yield

In this study, an activated natural dolomite catalyst is used as catalyst for the palm empty fruit bunches (PEFB) pyrolysis to produce bio-oil. The research was conducted in fixed bed reactors operating in batches by varying several parameters, which are temperature (400-600°C) and nitrogen gas flow rate (100-300 mL.min-1). The results show that the catalytic pyrolysis process using an activated natural dolomite catalyst obtains a maximum liquid yield of 35.87% when using a 500°C catalytic pyrolysis temperature and the rate of nitrogen gas is 100 cm3/minute, while the yield of gas and solids is 53.12% and 11.76%, respectively. The use of the dolomite activation catalyst influences the product distribution of pyrolysis and the bio-oil chemical compounds.

scholarly journals Modelling of Carbon Monoxide and Carbon Dioxide Methanation under Industrial Condition

2020 ◽  
Author(s):  
Artur Wodołażski
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Process Simulation ◽  
Physical Modeling ◽  
Dynamic Properties ◽  
Fixed Bed ◽  
Industrial Condition ◽  
Development Models ◽  
Fixed Bed Reactors ◽  
Carbon Dioxide Methanation

The development of methanation technology is supported by detailed modeling and process simulation to optimize the design and study of its reaction dynamic properties. The chapter presents a discussion of selected catalysts and its kinetic models in the methanation reaction. The development models of fixed-bed reactors in the methane synthesis were also presented. Chemical and physical modeling of methanation reactions with optimization, exploitation, and the analysis of critical processes in time is an important contribution to the technology modernization.

Laboratory Studies of Microscopic Dispersion Phenomena

1962 ◽  
Vol 2 (01) ◽  
pp. 1-8 ◽  
Author(s):  
R.J. Blackwell
Keyword(s):  
Porous Medium ◽  
Molecular Diffusion ◽  
Fixed Bed ◽  
Packed Bed ◽  
Oil Reservoirs ◽  
Fluid Mixing ◽  
Dispersion Coefficients ◽  
Mixing Processes ◽  
Molecular Diffusivity ◽  
Fixed Bed Reactors

Abstract This paper presents the results of a laboratory investigation of the process by which one fluid is displaced from a porous medium by a second fluid which is miscible with the first. The study included investigations of the microscopic mixing processes and of the gross displacement behavior. The results of this study are useful in scaling small bench-scale models or reactors to represent larger systems such as oil reservoirs or large, fixed bed reactors. Mixing in both the direction of flow and perpendicular to the direction of flow was measured in sand-packed columns. Dispersion coefficients were calculated from data obtained over a range of rates for various fluid pairs and sand-grain sizes. The data are presented by plotting the ratios of the dispersion coefficients divided by the molecular diffusivity vs a dimensionless parameter relating the forward transport by convection to lateral transport by diffusion. It was found that both longitudinal and lateral mixing are governed by molecular diffusion at low rates and by convection at high rates. At high rates, however, the lateral dispersion coefficients are about 1/24th those in the longitudinal direction. The ratio of lateral to longitudinal dispersion coefficients is compared with that predicted by various mathematical models of the pore system in a packed bed. The use of dispersion coefficients in scaling laboratory models to represent solvent floods in oil reservoirs is discussed briefly. Introduction The physical processes involved in the displacement of one fluid from a porous medium by a second fluid which is miscible with the first are fundamentally important in many diverse fields. For example, chemical engineers have been particularly concerned with the relationship of such fundamental aspects of displacement processes as the distribution of heat and mass, and the effect of fluid mixing on reactor efficiency. The specific problem of fluid mixing in fixed bed reactors has been investigated by Bernard and Wilhelm and others. Because high reactor efficiencies often require turbulent motion of the fluids within the individual flow channels of the porous medium, the emphasis in most of these studies has centered on fluid mixing in the turbulent or almost turbulent flow regimes. The mixing between miscible fluids in the laminar flow regime at very low Reynold's numbers is of particular interest in the field of and in recovery of oil.

scholarly journals A Simplified Method for Modeling of Pressure Losses and Heat Transfer in Fixed-Bed Reactors with Low Tube-to-Particle Diameter Ratio

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 784
Author(s):  
Tymoteusz Świeboda ◽  
Renata Krzyżyńska ◽  
Anna Bryszewska-Mazurek ◽  
Wojciech Mazurek ◽  
Alicja Wysocka
Keyword(s):  
Porous Medium ◽  
Cross Section ◽  
Fixed Bed ◽  
Particle Diameter ◽  
Weighted Average ◽  
Diameter Ratio ◽  
Fixed Bed Reactor ◽  
Fixed Bed Reactors ◽  
Simplified Method ◽  
Medium Method

This manuscript presents a simplified method of modeling fixed-bed reactors based on the porous medium. The proposed method primarily allows the necessity of precisely mapping the internal structure of the bed—which usually is done using real object imaging techniques (like X-ray tomography) or numerical methods (like discrete element method (DEM))—to be avoided. As a result, problems with generating a good quality numerical mesh at the particles’ contact points using special techniques, such as by flattening spheres or the caps method, are also eliminated. The simplified method presented in the manuscript is based on the porous medium method. Preliminary research has shown that the porous medium method needs modifications. This is because of channeling, wall effects, and local backflows, which are substantial factors in reactors with small values of tube-to-particle-diameter ratio. The anisotropic thermal conductivity coefficient was introduced to properly reproduce heat transfer in the direction perpendicular to the general fluid flow. Since the commonly used fixed-bed reactor models validation method based on comparing the velocity and temperature profiles in the selected bed cross-section is not justified in the case of the porous medium method, an alternative method was proposed. The validation method used in this work is based on the mass-weighted average temperature increase and area-weighted average pressure drop between two control cross-section of the reactor. Thanks to the use of the described method, it is possible to obtain satisfactorily accurate results of the fixed-bed reactor model with no cumbersome mesh preparation and long-term calculations.

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