Efficient modeling of the nonlinear dynamics of tubular heterogeneous reactors

Badillo-Hernández, Ulises; Álvarez, Jesús; Álvarez-Icaza, Luis

doi:10.1016/j.compchemeng.2019.01.018

Cited by 14 publications

(5 citation statements)

References 53 publications

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“…The first is a constant stoichiometric ratio. Secondly, we did not investigate the possible multiplicity of stationary solutions 128 . Finally, the fuel consumption was set constant, that is, it was assumed that the unburned residue is continuously removed from the reactor.…”

Section: Resultsmentioning

confidence: 99%

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Mathematical modeling of tar conversion on downdraft biomass gasification processes

Donskoy

2023

Biofuels Bioprod Bioref

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The article concerns some problems associated with the use of low‐grade fuels for the production of syngas in fixed‐bed gasifiers. Syngas is typically used to feed internal combustion engines in small power systems. Gas quality can be understood as its various characteristics, such as calorific value, the content of individual components (for example, hydrogen), low tar and soot content, and so forth. Achieving these quality criteria often requires specific conditions for the gasification process, in addition, some of them may be limited by additional requirements that are associated with thermal stability or fuel conversion requirements. When evaluating the technical and economic characteristics of gasification‐based power plants, the optimal efficiency does not always correspond to the higher efficiency of the gasification process and the quality of producer gas. In this regard, the aim is to develop optimization methods for different criteria and to create regime maps that cover physically achievable options. Novel mathematical models of tar conversion are proposed, allowing investigation of the dependencies of tar yield on gasification conditions, including the addition of catalysts or staged air supply. Computational tools based on thermodynamic and kinetic models make it possible to solve some of these problems, first of all, to consider and compare the efficiency of various methods for reducing tar content in producer gas (staged gasification, fuel mixing, thermal, and catalytic methods of tar elimination). The choice of relatively simple mathematical models allows us to conduct numerical calculations in a wide range of conditions and to optimize the parameters of biofuel conversion plants. This approach allows a more flexible choice of gasifier operating conditions, including its work as a part of a power unit. Optimal parameters are calculated for specific conditions: secondary air ratio (1–20%) and fraction of catalytic material (5–10%). The results may be used in the analysis and choice of biofuel gasification conditions at small power plants.

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Section: Resultsmentioning

confidence: 99%

“…Secondly, we did not investigate the possible multiplicity of stationary solutions. 128 Finally, the fuel consumption was set constant, that is, it was assumed that the unburned residue is continuously removed from the reactor. Analysis of these limitations may be the subject of future research.…”

Section: Donskoymentioning

confidence: 99%

Mathematical modeling of tar conversion on downdraft biomass gasification processes

Donskoy

2023

Biofuels Bioprod Bioref

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“…A large number of industrial processes exhibit temporal and spatial evolution such as energy storage, tubular chemical reactor, diffusion and fluid dynamics, which are collectively referred to as distributed parameter systems (DPSs). Contrary to lumped parameter systems (LPSs), DPSs are usually described by sets of partial differential equations (PDEs) like Navier–Stokes equations, which provide a better understanding of the systems for developing efficient optimization and control methods. , A commonly desired aim to operate practical systems is to achieve an expected distribution of certain physical quantities from the perspective of DPSs in a large number of manufacturing processes.…”

Section: Introductionmentioning

confidence: 99%

Self-Optimizing Control Strategy for Distributed Parameter Systems

Tang

Zhou

et al. 2023

Ind. Eng. Chem. Res.

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Real-time optimization (RTO) has been a popular approach for addressing optimal operation by repetitively optimizing online. However, this approach is impractical for distributed parameter systems (DPSs) due to its expensive computational cost. Self-optimizing control (SOC) has emerged as a promising alternative strategy, which achieves acceptable optimality by controlling the designed controlled variables (CVs) at constant set points without reoptimizing. Motivated by this, the existing lumped parameter SOC method is for the first time expanded to a typical class of DPSs based on a high-fidelity discrete-space model. Starting from an infinite-order system itself, the SOC problem is constructed as the minimal loss functional regarding the CVs through the operator operation and variational method. To obtain an operational analytical solution of CVs, the optimization problem is reformulated based on the discrete-space system derived by the finite difference. Considering the variety of sensor and actuator placements, the CVs are analytically designed with the minimal static loss through the stacking matrix approach. Finally, a case study of a plug-flow reactor is presented to demonstrate the feasibility of the proposed approach to achieve optimal operation for DPSs.

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“…However, when working with immobilized enzymes internal and/or external diffusional resistances (IDR/EDR) are likely to occur regardless of the method of immobilization [8][9][10]. Thus, the design and optimization of such reactors are not easy tasks compared to the transport mechanism in such a wall-cooled FXBR that consists of convective and dispersive mass transport as well as convective and conductive energy transport in the bulk phase, mass and heat transport between the solid and fluid phase, heat transfer between the reaction mixture and the cooling (heating) agent, dispersive mass and conductive energy transport and biocatalytic conversion in the solid phase ( Figure 1) [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Analytical Determination of the Optimal Feed Temperature for Hydrogen Peroxide Decomposition Process Occurring in Bioreactor with a Fixed-Bed of Commercial Catalase

Grubecki

2020

Catalysts

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The hydrogen peroxide-immobilized commercial catalase system was chosen to estimate the optimal feed temperature (OFT) for fixed-bed reactor (FXBR). This feed temperature was obtained based on analytical solution by maximizing the time-averaged substrate conversion under a constant feed flow rate and temperature constraints. In calculations a set of partial differential equations describing the conservation equation for fixed-bed reactor, assuming plug flow and kinetic equation for the rate of enzyme parallel deactivation was taken into account. The model is based on kinetic, and mass-transfer parameters estimated previously in a real decomposition process of hydrogen peroxide (HP). The simulation showed that the OFT is strongly dependent on hydrogen peroxide feed concentration, feed flow rate and diffusional resistances expressed by biocatalyst global effectiveness factor. It has been shown that the more significant diffusional resistances and the higher HP conversions are, the higher the optimal feed temperature is. The calculated values of the OFT were verified with the experimental results obtained in the model reactor at selected values of the feed flow rate. Presented analysis poses a significant simplification in a numerical computational procedure and can be very useful for engineers to select the temperature condition at which bioreactor productivity is expected to be maximal.

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Efficient modeling of the nonlinear dynamics of tubular heterogeneous reactors

Cited by 14 publications

References 53 publications

Mathematical modeling of tar conversion on downdraft biomass gasification processes

Mathematical modeling of tar conversion on downdraft biomass gasification processes

Self-Optimizing Control Strategy for Distributed Parameter Systems

Analytical Determination of the Optimal Feed Temperature for Hydrogen Peroxide Decomposition Process Occurring in Bioreactor with a Fixed-Bed of Commercial Catalase

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