Multiple steady states and transitional regimes in a cylindrical fixed-bed catalytic reactor

Bostandzhiyan, S. A.; Шкадинский, К. Г.

doi:10.1134/s0040579510020016

Cited by 4 publications

(3 citation statements)

References 5 publications

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“…On the contrary, the heterogeneous model allows for the distinction between gas and catalyst-phase dispersion and, thus, accounts for two separate energy-based Bodenstein numbers (Bo eg , Bo ec ). For real fixed-bed reactors, the mass-based Bodenstein number is reported to be three to ten times higher than the energy-based Bodenstein number (Puszyński et al, 1981;Bostandzhiyan and Shkadinskii, 2010). Thus, energy back-mixing is the dominating axial dispersion mechanism within fixed-bed reactors (Mears, 1976).…”

Section: Methodsmentioning

confidence: 96%

Novel Multiplicity and Stability Criteria for Non-Isothermal Fixed-Bed Reactors

Bremer

Sundmacher

2021

Front. Energy Res.

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With the increasing need to utilize carbon dioxide, fixed-bed reactors for catalytic hydrogenation will become a decisive element for modern chemicals and energy carrier production. In this context, the resilience and flexibility to changing operating conditions become major objectives for the design and operation of real industrial-scale reactors. Therefore steady-state multiplicity and stability are essential measures, but so far, their quantification is primarily accessible for ideal reactor concepts with zero or infinite back-mixing. Based on a continuous stirred tank reactor cascade modeling approach, this work derives novel criteria for stability, multiplicity, and uniqueness applicable to real reactors with finite back-mixing. Furthermore, the connection to other reactor features such as runaway and parametric sensitivity is demonstrated and exemplified for CO2 methanation under realistic conditions. The new criteria indicate that thermo-kinetic multiplicities induced by back-mixing remain relevant even for high Bodenstein numbers. In consequence, generally accepted back-mixing criteria (e.g., Mears’ criterion) appear insufficient for real non-isothermal reactors. The criteria derived in this work are applicable to any exothermic reaction and reactors at any scale. Ignoring uniqueness and multiplicity would disregard a broad operating range and thus a substantial potential for reactor resilience and flexibility.

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Section: Methodsmentioning

confidence: 96%

Novel Multiplicity and Stability Criteria for Non-Isothermal Fixed-Bed Reactors

Bremer

Sundmacher

2021

Front. Energy Res.

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“…Prokof'ev et al [10] have shown the fundamental feasibility of self-oscillatory modes of reactor operation. Bostandzhian and Shkadinskii [11] analytically identified five steady states, two of which are unstable, two are high-temperature, and one is lowtemperature. The steady states come in various combinations to form seven regions, depending on the gas flow rate and the temperature of the coolant.…”

Section: Introductionmentioning

confidence: 98%

“…Calculations for a flow reactor in the one-dimensional formulation of the problem were performed in [7][8][9][10][11]. Rabonovich et al [7] experimentally confirmed the existence of oscillatory modes of combustion of a gas mixture moving through hollow tubes and through a porous medium.…”

Section: Introductionmentioning

confidence: 98%

Simulation of heat transfer and chemical reaction of a combustible mixture in a flow reactor

Burkina

Moiseeva

2014

Combust Explos Shock Waves

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The modes of operation of a flow reactor with an inert inner body were investigated. A numerical study of the combustion of a methane-air mixture was performed. The parameter ranges of possible modes of reactor operation were determined depending on the dimensionless parameters of heat exchange of the mixture with the inert body and the side surface and the mixture flow parameter. The existence of non-uniqueness regions of operation modes is shown. The influence of the inert inner body on the distribution of the regions of possible modes of reactor operation is considered.

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