Efficient diagnosis of grate-fired biomass boilers by a simplified CFD-based approach

Rezeau, Adeline; Díez, Luis I.; Royo, Javier; Díaz-Ramírez, Maryori C.

doi:10.1016/j.fuproc.2017.11.024

Cited by 22 publications

(11 citation statements)

References 32 publications

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“…The turbulence model used is the realizable k-ε model, which is commonly used in biomass combustion system simulations [23,25,26]. The radiation model chosen is the discrete ordinates model, which has been modified to take into account the contribution of the solid phase [45].…”

Section: Gas Phasementioning

confidence: 99%

“…Eulerian models have a lower computational cost than Lagrangian models, being a more comprehensive approach than one-dimensional models [23]. These models usually consider two zones, the bed, defined as a porous zone where the solid and gas phases coexist, and the freeboard, set as a simple fluid, allowing dynamic coupling between both phases [25][26][27][28][29]. Eulerian models have been successfully used to simulate systems under different air/oxy-fuel conditions [28] and on different scales, from small experimental plants [27], to medium- [25] and large-scale systems [26,29].…”

Section: Introductionmentioning

confidence: 99%

“…These models usually consider two zones, the bed, defined as a porous zone where the solid and gas phases coexist, and the freeboard, set as a simple fluid, allowing dynamic coupling between both phases [25][26][27][28][29]. Eulerian models have been successfully used to simulate systems under different air/oxy-fuel conditions [28] and on different scales, from small experimental plants [27], to medium- [25] and large-scale systems [26,29]. Although these models do not treat the fuel bed as individual particles, physics algorithms can be implemented to simulate the movements and compaction of the solid fuel inside the systems [30,31].…”

Section: Introductionmentioning

confidence: 99%

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CFD Simulation of an Internally Cooled Biomass Fixed-Bed Combustion Plant

et al. 2021

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The reduction of bed temperature in fixed-bed biomass combustion is an effective measure to lower pollutant emissions. Air staging and bed cooling solutions are active strategies to decrease the fuel bed temperature. This work presents a CFD study of a biomass fixed-bed combustion plant that is equipped with an internal cooling bed system. Eight different cases are calculated to analyze the effect of the total airflow, air staging ratios and bed cooling system on biomass combustion. The findings are validated against experimental data from the literature. The results show good accordance between the numerical results and the experimental data. The primary airflow rate has the biggest influence on the bed’s maximum temperatures. The internal bed cooling system is able to achieve an average bed temperature reduction of 21%, slowing the biomass thermal conversion processes. Bed cooling techniques can be combined with air staging and primary airflow reduction to reduce bed temperatures in order to reduce pollutant emissions and other undesirable phenomena, such as fouling or slagging.

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Section: Gas Phasementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CFD Simulation of an Internally Cooled Biomass Fixed-Bed Combustion Plant

et al. 2021

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“…To forecast the effects of such a co-combustion process, for example, the emission of CO 2 , CO, NO x , SO 2 , as well as the content of combustible parts in solid products (in slag and ash), the temperature of the obtained flue gases, and the thermal efficiency of the process, we apply process characteristics [1][2][3][4][5]. They are used as analytical functional relationships between the parameters defining each of the mentioned effects and the quantities controlling the process, for example, the amount of fuels (share of waste), their composition, excess air for combustion, and the method of their supply to the process [1].…”

Section: Introductionmentioning

confidence: 99%

Application of Data Validation and Reconciliation to Improve Measurement Results in the Determination Process of Emission Characteristics in Co-Combustion of Sewage Sludge with Coal

Kozioł

2021

Sustainability

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One of the actions popularized worldwide to reduce the consumption of fossil fuels is the combustion of renewable fuels and the co-combustion of both of these fuels. To properly implement combustion and co-combustion processes in power-generation installations, operational characteristics, including emission characteristics are required. To determine these characteristics, tests must be conducted, within the scope of which, for individual operating stages of the installation’s work, the readings collected from a relatively large number of control and measurement instruments should be taken into account. All these instruments have different levels of accuracy, which, among other factors, bring about lower adequacy of the characteristics determined on the basis of these measurements. The objective of this study is to present possible adaptations of data validation and reconciliation methods to increase the adequacy of emission characteristics for the process of co-combustion of fuels. The methodology is discussed based on the example of studies on the co-combustion process of sewage sludge with coal in a grate furnace. The aforementioned characteristics were determined based on measurement tests of gaseous emissions of flue gas components. The tests were carried out for various preset operational conditions of the process, such as the thickness of fuel layer on the grate, the share of sludge in the fuel, the humidity of the sludge, the theoretical ratio of excess air to combustion, and the distribution of air stream during the process. The research object is described and detailed research results concerning two exemplary measurement tests are given, as well as the most important results referring to the whole research. The performed calculations indicate the necessity to take into account often significant corrections, which can amount to about 10% of the measured value.

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“…He was focused on an analysis of temperature, velocity, and species field of exhaust gas within a boiler, which provided to the optimization of the burning process. Moving grate biomass boilers models realized in two different scales (250 kW and 4 MW) were analyzed by Rezeau et al [20] and Bermúdez et al [21] in terms of composition and temperature distribution of flue gas. Klason et al [22] analyzed a radiation heat transfer process in two various scales (10 kW and 50 MW) during biomass burning in fixed bed furnaces.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Analysis of Heat Transfer for Solid Fuels Combustion in Fixed Bed Conditions

Judt

2020

Energies

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The paper concerns the analysis of the heat transfer process that occurred during solid fuel burning in fixed bed conditions. The subject of the analysis is a cylindrical combustion chamber with an output of 12 kW heating power equipped with a retort burner for hard coal and biomass combustion. During the research, a numerical and experimental study is performed. The analysis is prepared for various heat load of the combustion chamber, which allowed for the reconstruction of real working conditions for heating devices working with solid fuels combustion. The temperature distribution obtained by the experimental way is compared with results of the numerical modeling. Local distribution of principal heat transfer magnitudes like a heat flux density and a heat transfer coefficient that occurred on the sidewall of the combustion chamber is analyzed. The analysis showed, that the participation of convection and radiation in the overall heat transfer process has resulted from the heat load of the heating device. Research results may be used for improving an analytical approach of design process taking place for domestic and industrial combustion chambers.

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Efficient diagnosis of grate-fired biomass boilers by a simplified CFD-based approach

Cited by 22 publications

References 32 publications

CFD Simulation of an Internally Cooled Biomass Fixed-Bed Combustion Plant

CFD Simulation of an Internally Cooled Biomass Fixed-Bed Combustion Plant

Application of Data Validation and Reconciliation to Improve Measurement Results in the Determination Process of Emission Characteristics in Co-Combustion of Sewage Sludge with Coal

Numerical and Experimental Analysis of Heat Transfer for Solid Fuels Combustion in Fixed Bed Conditions

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