Kinetic Expression with Diffusion Correction for Ammonia Synthesis on Industrial Catalyst

“…The mass balance in one reactor is expressed only regarding nitrogen conversion (Equations (20) and (21)) because only one reaction takes place in converter [2]. The only difference between the following relations is the area of reactor.…”

Section: Mass Momentum and Energy Balances (Adiabatic Reactors)mentioning

confidence: 99%

“…They generally contain partial pressures [1] or chemical activities [2] in formulation. One of the first models was presented by the authors Emmett and Kummer [3].…”

Section: Introductionmentioning

confidence: 99%

Modeling and Numerical Simulation of Ammonia Synthesis Reactors Using Compositional Approach

Jorqueira¹,

Neto²,

Rodrigues³

2018

ACES

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Ammonia synthesis reactors operate in conditions of high pressure and high temperature. Consequently, the flow inside these reactors always presents interaction between components in the feed mixture. A modeling accounts these interactions with pressure, temperature and the molar fraction is essential to converter simulation more realistic. The compositional approach based on cubic equations of state provides the influences of the component of a gas mixture using mixing rules and binary interaction parameters. This multicomponent description makes the model more robust and reliable for properties mixture prediction. In this work, two models of ammonia synthesis reactors were simulated: adiabatic and autothermal. The fitted expression of Singh and Saraf was used. The adiabatic reactor model presented a maximum relative error of 1.6% in temperature and 11.4% in conversion while the autothermal reactor model presents a maximum error of 2.7% in temperature, when compared to plant data. Furthermore, a sensitivity analysis in input variables of both converter models was performed to predict operational limits and performance of the Models for Ammonia Reactor Simulation (MARS).

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“…In order to exclude the effect of inter-and intraparticle diffusion, the size of catalyst particles was chosen to have an equivalent diameter less than 1.5 mm [12].…”

Section: Reversed Flow Ammonia Synthesismentioning

confidence: 99%

“…To activate the prereduced type industrial catalyst (SA-1-V), a suitable method recommended by Nielsen [12] was used. The particle size of the catalyst was 1.0±1.5 mm; thus, a significant pore and film diffusion restriction could not develop under the measurement conditions.…”

Section: Experimental Equipmentmentioning

confidence: 99%

Experimental Study of Flow Reversal Ammonia Synthesis

Egyházy¹,

Kovács

Scholtz

1998

Chem. Eng. Technol.

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Operation of fixed bed reactors with periodic flow reversal as proposed by Matros and co-workers is an unconventional mode of operation for exothermic, equilibrium limited catalytic reactions. In the present paper, reverse flow ammonia synthesis at 240± 300 bar over a promoted iron catalyst is considered. The catalyst had a particle size of 1.0±1.5 mm to neglect the intra-and interparticle transport intrusions. Temperature profiles, which developed and moved back and forth through the laboratory scale reactor, depending upon the direction of the flow, and the exit ammonia concentration were monitored. The time average ammonia concentration observed in the non-steady-state of operation was exceeded by 5±27% the ammonia concentration obtained in similar but under steady-state conditions. The enhancement in the ammonia production was mainly due to the transient state of the catalyst surface and the dynamic behavior of the reactor bed.

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Kinetic Expression with Diffusion Correction for Ammonia Synthesis on Industrial Catalyst

Cited by 114 publications

References 16 publications

A reliable control for the ammonia loop facing limit‐cycle and snowball effects

A reliable control for the ammonia loop facing limit‐cycle and snowball effects

Modeling and Numerical Simulation of Ammonia Synthesis Reactors Using Compositional Approach

Experimental Study of Flow Reversal Ammonia Synthesis

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