Mathematical modelling of straw combustion in a moving bed combustor: A two dimensional approach

Miljković, Biljana; Pešenjanski, Ivan; Vićević, Marija

doi:10.1016/j.fuel.2012.08.017

Cited by 25 publications

(18 citation statements)

References 18 publications

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“…As already noted in the Introduction, today's models tend to capture as many phenomena as possible, which inevitably leads to complexities. A 2-D model of straw combustion presented in [8] demonstrated that modelling can provide information about aspects such as temperature profile of the fuel bed, combustion rate and the produced chemical species which would not be available otherwise. But such a model requires the use of high-speed computer in order to obtain acceptable results in a short time.…”

Section: Discussionmentioning

confidence: 99%

“…An overview of various models for the combustion of biomass at the mechanical grate is given in [12]. A moving grate [6][7][8] is a typical example of combustion in a fixed bed (the grate carries a bed through the combustion chamber, while the bed does not move). In contrast, other mechanized grates (ibid,) cause displacement in the fuel bed.…”

Section: Introductionmentioning

confidence: 99%

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Mathematical modeling of lignite combustion in a bed: A one-dimensional approach

Miljković

Pešenjanski

2016

THERM SCI

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Thermal plant design and choice of suitable technology requires the understanding of the fuel thermo-chemical properties. The reactions that consist of different phases may be approached in two ways. One is to determine the kinetics of each individual reaction and its interaction with the environment. The other method is to use an integrated approach, when, based on the results, the summary formula for the behavior of combustible matter is obtained. This is an empirical approach. Despite possible objections, particularly regarding its accuracy, the narrow range of applicability etc., the attractiveness of this procedure is evident due to direct results, simplicity and far lower costs to the experiment. That is the reason why this paper focuses on determining the kinetic parameters of the integrated model of group reactions that are part of the combustion of lignite at low temperatures. The paper develops a simple mathematical model of the combustion process for lignite in bed which is then confirmed by modeling the experimental results.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mathematical modeling of lignite combustion in a bed: A one-dimensional approach

Miljković

Pešenjanski

2016

THERM SCI

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“…(1) -(6) and initial and boundary conditions for differential Eq. (8), are required to complete the system of equations.…”

Section: Numerical Solutionmentioning

confidence: 99%

“…Miljković et al [8] developed an original numerical model for the surface combustion of straw in a moving bed and relevant equations solved using original programme realised in C++ to simulate heterogeneous characteristics of the burning process. The model provides information concerning temperature front propagation, reaction front rate and remaining gas species composition in bed.…”

Section: Introductionmentioning

confidence: 99%

Modeling for Pyrolysis of Solid Biomass

Miljković

Nikolovski

Mitrović

et al. 2019

Period. Polytech. Chem. Eng.

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In comparison to coal, biomass is characterized by a higher content of volatile matter. It is a renewable source of energy which has many advantages from an ecological point of view. Understanding the physical phenomena of pyrolysis and representing them with a mathematical model is the primary step in the design of pyrolysis reactors. In the present study, an existing mathematical model is used to describe the pyrolysis of a single solid particle of biomass. It couples the heat transfer equations with the chemical kinetics equations.A finite difference method is used for solving the heat transfer equation and the two-step pyrolysis kinetics equations. The model equation is solved for a slab particle of equivalent dimension 0.001 m and temperature ranging from 300 to 923 K. An original numerical model for the pyrolysis of wood chips is proposed and relevant equations solved using original program realized in MATLAB.To check the validity of the numerical results, experimental results of pyrolysis of woody biomass in laboratory facility was used.The samples were heated over a range of temperature from 300 to 923 K with three different heating rates of 21, 32 and 55 K/min, and the weight loss was measured. The simulation results as well as the results obtained from thermal decomposition process indicate that the temperature peaks at maximum weight loss rate change with the increase in heating rate. The experimental results showed that the simulation results are in good agreement and can be successfully used to understand the degradation mechanism of solid reaction.

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“…The work suggested that the effective heat conductivity of the bed, the straw heat capacity and the bed packing have the most influence on the quality of the model predictions. A twodimensional, steady model of straw combustion presented in Miljkovic et al [9] demonstrated that modeling can provide information like a temperature profile of the fuel bed, a combustion rate and the produced chemical species which would not otherwise be available. Girgis and Hallett [10] used a mathematical model and experiments to analyze combustion in an overfeed packed bed.…”

Section: Introductionmentioning

confidence: 99%