Control Simulation in Ammonia Production

Shah, M.J.

doi:10.1021/ie50685a010

Cited by 46 publications

(15 citation statements)

References 2 publications

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“…The specific heat of the different components is calculated from the equations given by Shah [5]. It should be noted that the average molar specific heat of mixture varies with the degree of conversion.…”

Section: Energy Balance Equation On the Bulk Gasmentioning

confidence: 99%

Steady‐State Modeling and Simulation of an Axial‐Radial Ammonia Synthesis Reactor

Panahandeh¹,

Fathikaljahi

Mohebbi

2003

Chem Eng & Technol

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A two-dimensional model was developed for an axial-radial ammonia synthesis reactor of the Shiraz petrochemical plant. In this model, momentum and continuity equations as well as mass and energy balance equations are solved simultaneously by orthogonal collocation on the finite element method to obtain pressure, velocity, concentration and temperature profiles in both axial and radial directions. For the catalyst particle, the effectiveness factor is calculated by solving a two-point boundary value differential equation. The boundary conditions for the Navier-Stokes and continuity equations are obtained by using equations representing the phenomena of gases splitting or joining in different streams and going through holes in a thin wall. The results of the mathematical model have been compared with the plant data and a good agreement is obtained.

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Section: Energy Balance Equation On the Bulk Gasmentioning

confidence: 99%

Steady‐State Modeling and Simulation of an Axial‐Radial Ammonia Synthesis Reactor

Panahandeh¹,

Fathikaljahi

Mohebbi

2003

Chem Eng & Technol

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“…Other pertinent data like the thermodynamic data, the equilibrium constant, etc. have been taken from the work of Shah et al (1967).…”

Section: [J] = -C[b]-'vymentioning

confidence: 99%

A Methodology for the a Priori Selection of Catalyst Particle Models

Reddy¹,

Murty²

1995

Ind. Eng. Chem. Res.

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Numerical simulation with catalytic reactor models demands the use of computationally efficient intraparticle models because of the need for repetitive evaluation of the effectiveness factors. Some of the most widely used models of this type are the flux and the dusty-gas models, based on the Stefan-Maxwell equation, and the effective diffusivity model. But these are known to have varying degrees of rigour and computational speed, and in the absence of any conclusive evidence about the relative efficacy of these models, one often tends to use complex models in situations when simpler models suffice. The present work addresses this problem and suggests a procedure for the a priori selection of a suitable intraparticle model in a given situation. This is based on the interactions among the various constituents making up the reaction system and the type of regime prevailing within the catalyst pellet. With the help of this methodology, it has been shown that the effective diffusivity model, in spite of its shortcomings, could be safely used even when the intraparticle regime is diffusion-controlled, if the flux interactions among the species are low. Its use should however be restricted to cases with reaction-rate-controlled regimes, if there are strong interactions.

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“…The effectiveness factor (ŋ) is relatively small (0.3-0.6) along the length of the reactor. The concept of the effectiveness factor as a measure of importance of diffusion limitation for gas-solid catalytic reactions has gone a long way (Appl, 2007;Isla et al, 1993;Jennings, 1991;Shah, 1967;Butt, 2000., Dyson andSimon, 1968;Ukpaka, 2013). The ammonia reaction is diffusion limited within the catalyst pellet i.e.…”

Section: Introductionmentioning

confidence: 99%

Model prediction on the reliability of fixed bed reactor for ammonia production

Int¹

2019

Preprint

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In this research work Haber process was employed to examine the reliability of the functional parameters and coefficient on ammonia production using the fixed bed reactor with hydrogen gas and nitrogen used as the main source of the reactant. Mathematical models were developed to monitor and predict the effectiveness factors, nitrogen fractional conversion, temperature, component mole fraction, hydrogen mole fraction, and ammonia mole fraction profile for the various cases considered during the investigation. The simulated parameters for case 1, 2 and 3 for components of total feed flow, pressure, reactor bed volume and feed composition influence the reliability of the functional parameters and the coefficient of the fixed bed reactor for optimum yield of ammonia. The developed models were simulated using Matlab program to evaluate the functional parameters and the results obtained from the system in terms of optimum yield factor indicate 30% to 34% increase in ammonia production. The increase in the performance evaluation concept revealed the reliability of the developed model in monitoring and predicting the rate of production of ammonia in a fixed bed reactor.

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Control Simulation in Ammonia Production

Cited by 46 publications

References 2 publications

Steady‐State Modeling and Simulation of an Axial‐Radial Ammonia Synthesis Reactor

Steady‐State Modeling and Simulation of an Axial‐Radial Ammonia Synthesis Reactor

A Methodology for the a Priori Selection of Catalyst Particle Models

Model prediction on the reliability of fixed bed reactor for ammonia production

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