Sensitivity and Bifurcation Analysis of a Differential-Algebraic Equation Model for a Microbial Electrolysis Cell

Dudley, Harry J.; Lu, Lu; Ren, Zhiyong Jason; Bortz, David M.

doi:10.1137/18m1172223

Cited by 10 publications

(11 citation statements)

References 38 publications

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“…The effect of change in anodic compartment volume was studied, the results showed that increasing the volume of anodic compartment increases the hydrogen production rate but it does not have any effect on current I MEC . The Effect of change in the maximum growth rate (µm,m) by acetoclastic methanogenic microorganism was studied in the range from 1.5 ≤ µ m, m ≤ 3.0 ℎ and the study showed that maximum growth rate only has effect in the initial start of the process and minor effect on current I MEC and the rate of hydrogen production.Sensitivity analysis was conducted by Dudley [19] on the main parameters of MEC batch-cycle reactor, and it was found that μ max, a , q max, a , K S,a , K M , and Y M have greatest effect on the current density in the study. The increase of μ max,a , q max,a , and Y M , increases the current density.…”

Section: B Sensitivity Analysis On Mec Parametersmentioning

confidence: 99%

A Reduced Model for Microbial Electrolysis Cells

Aboelela,

Soliman*,

Ashour

2020

IJITEE

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Microbial electrolysis cells (MECs) are breakthrough technology of cheap hydrogen production with high efficiency. In this paper differential-algebraic equation (DAE) model of a MEC with an algebraic constraint on current was studied, simulated and validated by implementing the model on continuous-flow MECs. Then sensitivity analysis for the system was effectuated. Parameters which have the predominating influence on the current density and hydrogen production rate were defined. This sensitivity analysis was utilized in modeling and validation of the batch-cycle of MEC. After that parameters which have less influence on MEC were eliminated and simplified reduced model was obtained and validated. Finally, MEC energy productivity was maximized by optimization of operating conditions.

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Section: B Sensitivity Analysis On Mec Parametersmentioning

confidence: 99%

A Reduced Model for Microbial Electrolysis Cells

Aboelela,

Soliman*,

Ashour

2020

IJITEE

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“…Versions of the semi-explicit index 1 DAE model for the MEC have been described previously in [7,8,9]. Our model differs from [8] by not including fermenting microorganisms that convert a complex substrate into 1.1 Model 3 a single compound such as acetate.…”

Section: Modelmentioning

confidence: 99%

“…For the simulations below, we generally use parameters from the first table of [7], with the following exceptions. The influent substrate concentration is S 0 = 100 and the maximum substrate consumption rates for each species are q max,m1,1 = q max,m2,1 = q max,e,1 = 14.…”

Section: Numerical Simulationsmentioning

confidence: 99%

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Competitive Exclusion in a DAE Model for Microbial Electrolysis Cells

Dudley¹,

Ren²,

Bortz³

2019

Preprint

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Microbial electrolysis cells (MECs) are devices that employ electroactive bacteria to perform extracellular electron transfer, enabling hydrogen generation from biodegradable substrates. Previously we analyzed a regular, semi-explicit, index 1 differential-algebraic equation (DAE) model for MECs. The model consists of ordinary differential equations (ODE) resembling chemostats or continuous stirred tank reactors (CSTRs), an ODE for a mediator involved in electron transfer, and an algebraic constraint for electric current and hydrogen production. This work characterizes asymptotic stability of equilibria in two biologically relevant versions of the model. Our goal is to determine the outcome of competition between methanogenic archaea and electroactive bacteria, because only the latter contribute to electric current and hydrogen production. We investigate global asymptotic stability in a model with finitely many species, Monod kinetics, different removal rates, and a constraint based on the Nernst and Butler-Volmer equations. If methanogens can grow at the lowest substrate concentration, then the equilibrium corresponding to competitive exclusion by methanogens is globally asymptotically stable. Establishing the analogous result for electroactive bacteria has proven challenging. As a first step towards characterizing stability of an electroactive-only equilibrium, we consider local asymptotic stability in a model with three types of microbes, general monotone kinetics, equal removal rates, and a general constraint. In this model, even if electroactive bacteria can grow at the lowest substrate concentration, a few additional conditions are required to guarantee local asymptotic stability. We also provide numerical simulations supporting these arguments. Our results suggest operating conditions that are most conducive to success of electroactive bacteria and current or hydrogen production in MECs.

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“…Other categories can be related to the complexity of the model, for instance, spatial dimension (1D, 2D, or 3D), time dependence, or steady state models. In this regard, most MEC models have been proposed as either ordinary differential equation (ODE) systems [21][22][23][24][25] or partial differential equation (PDE) systems [12,15,[26][27][28]. Generally, both model types also include algebraic equations (AE), resulting in ordinary differential algebraic equations (ODAE) and partial differential algebraic equations (PDAE).…”

Section: Introductionmentioning

confidence: 99%

A Catalytic Effectiveness Factor for a Microbial Electrolysis Cell Biofilm Model

2022

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The aim of this work is to propose a methodology to obtain an effectiveness factor for biofilm in a microbial electrolysis cell (MEC) system and use it to reduce a partial differential equation (PDE) biofilm MEC model to an ordinary differential equation (ODE) MEC model. The biofilm mass balances of the different species are considered. In addition, it is considered that all the involved microorganisms are attached to the anodic biological film. Three effectiveness factors are obtained from partial differential equations describing the spatial distributions of potential and substrate in the biofilm. Then, a model reduction is carried out using the global mass balances of the different species in the system. The reduced model with three uncertain but bounded effectiveness factors is evaluated numerically and analyzed in the sense of stability and parametric sensibility to demonstrate its applicability. The reduced ODE model is compared with a validated model taken from the literature, and the results are in good agreement. The biofilm effectiveness factor in MEC systems can be extended to the reduction of PDE models to obtain ODE models that are commonly used in optimization and control problems.

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Sensitivity and Bifurcation Analysis of a Differential-Algebraic Equation Model for a Microbial Electrolysis Cell

Cited by 10 publications

References 38 publications

A Reduced Model for Microbial Electrolysis Cells

A Reduced Model for Microbial Electrolysis Cells

Competitive Exclusion in a DAE Model for Microbial Electrolysis Cells

A Catalytic Effectiveness Factor for a Microbial Electrolysis Cell Biofilm Model

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