scholarly journals Simulation of Steam Reforming Tube with Shaped Particles

2016 ◽  
Vol 7 (1) ◽  
pp. 57 ◽  
Author(s):  
A.P. Kagyrmanova ◽  
N.V. Vernikovskaya ◽  
I.A. Zolotarsky ◽  
E.I. Smirnov ◽  
V.A. Kuzmin
Keyword(s):  
Steam Reforming ◽  
Radial Direction ◽  
Tube Wall ◽  
Homogeneous Model ◽  
Packed Bed ◽  
Intraparticle Diffusion ◽  
Simulated Performance ◽  
Reaction Stoichiometry ◽  
Gas Volume ◽  
Convective Mass Flux

<p>Shaped catalysts are widely used in steam reforming. A comprehensive mathematical model able to predict and compare performance of different shaped catalysts is developed. The two-dimensional pseudo homogeneous model accounts for heat transfer between the tube wall and catalyst bed, conductivity and diffusivity in the radial direction in the packed bed and intraparticle diffusion. Gas volume changing caused by reaction stoichiometry results in a radial convective mass flux. A verification of the model and simulated performance of different shaped catalysts in steam reforming of natural gas are presented.</p>

scholarly journals Measurement of Thermal Conductivity along the Radial Direction in a Vertical Cylindrical Packed Bed

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Swaren Bedarkar ◽  
Nurni Neelakantan Viswanathan ◽  
Nidambur Bharatha Ballal
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Crucial Role ◽  
Iron Ore ◽  
Radial Direction ◽  
Thermal Response ◽  
Packed Bed ◽  
Lumped Parameter ◽  
Scientists And Engineers

Heat transfer in packed beds and their thermal response have been of great interest for scientists and engineers for the last several years, since they play a crucial role in determining design and operation of reactors. Heat transfer of a packed bed is characterised through lumped parameter, namely, effective thermal conductivity. In the present studies, experiments were performed to investigate the thermal conductivity of a packed bed in radial direction. The packed bed was formed using iron ore particles. To determine the effective thermal conductivity a new transient methodology is proposed. The results obtained were compared with the models proposed by ZBS and Kunii and Smith.

Heat Transfer in Fixed Bed Elliptic Cylindrical Reactor via Two-Phase Model

2020 ◽  
Vol 400 ◽  
pp. 45-50
Author(s):  
Antonildo Santos Pereira ◽  
Rodrigo Moura da Silva ◽  
Maria Conceição Nóbrega Machado ◽  
Luan Pedro Melo Azerêdo ◽  
Anderson Ferreira Vilela ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Solid Phase ◽  
Homogeneous Model ◽  
Fixed Bed ◽  
Fluid Phase ◽  
Packed Bed ◽  
Two Phase ◽  
Heterogeneous Model ◽  
Fully Implicit ◽  
Cylindrical Reactor

The study of heat transfer in fixed bed tubular reactors of heated or cooled walls has presented great interest by the academy and industry. The adequate and safe design of such equipment requires the use of reliable and realistic mathematical. Unfortunately several studies are restrict to homogeneous model applied to circular and elliptic cylindrical reactors. Then, the objective of this work was to predict heat transfer in packed-bed elliptic cylindrical reactor, by using a proposed heterogeneous model. The mathematical model is composed for one solid phase and another fluid phase, in which the balance equation for each constituent is applied separately. The finite volume method was utilized to solve the partial differential equations using the WUDS scheme for interpolation of the convective and diffusive terms, and the fully implicit formulation. Results of the temperature distribution of the fluid and solid phases along the reactor are presented and analyzed. It was verified that the highest temperature gradients of the phases are located close to the wall and inlet of the reactor.

A 3D Transient Model for the Multiphase Flow in a Progressing-Cavity Pump

SPE Journal ◽  
2016 ◽  
Vol 21 (04) ◽  
pp. 1458-1469 ◽  
Author(s):  
Victor W. de Azevedo ◽  
João A. de Lima ◽  
Emilio E. Paladino
Keyword(s):  
Multiphase Flow ◽  
Flow Rate ◽  
Homogeneous Model ◽  
Volumetric Flow Rate ◽  
Volumetric Efficiency ◽  
Two Phase ◽  
Transient Model ◽  
Viscous Losses ◽  
Constant Displacement ◽  
Gas Volume

Summary This paper presents the development of a computational-fluid-dynamics (CFD) model for the 3D transient two-phase flow within a progressing-cavity pump (PCP). The model implementation was only possible because of the meticulous mesh-generation and mesh-motion algorithm, previously published by the authors, which is briefly described herein. In this algorithm, a structured mesh was generated by defining all nodes’ positions and connectivities, for each rotor position by means of FORTRAN subroutines, which were embodied into ANSYS CFX software. The model is capable of predicting accurately the volumetric efficiency and the viscous losses, and it provides detailed information of pressure and velocity fields and void distribution along the pump. Such information could be of fundamental importance for product development and/or optimization for field operation. In field applications, the common situation is that in which the oil comes into the pump accompanied with free gas, which characterizes a multiphase flow. Simplified models on the basis of the calculation of the backflow or “slippage,” which is subtracted from the displaced flow rate, fail to characterize the PCP performance under multiphase conditions because the slip is variable along the pump. In this model, the governing equations were solved with an element-based finite-volume method in a moving mesh. The Eulerian-Eulerian approach, considering the homogeneous model, is used to model the flow of the gas/liquid mixture. The compressibility of the gas is taken into account, which is one of the main shortcomings in positive/constant displacement pumps. The effects of the different gas-volume fractions (GVFs) in pump volumetric efficiency, pressure distribution, power, slippage flow rate, and volumetric flow rate were analyzed, and some new insights are presented about the slippage in PCPs operating in multiphase conditions. The results show that the developed model is capable of reproducing pump dynamic behavior under multiphase-flow conditions performed early in experimental works.

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