Comparative Analysis of Fluidized and Fixed Beds to Obtain Data on the Char Pellet's Combustion Regime

Ferreira, Tânia; Paiva, João Monney; Pinho, Carlos

doi:10.1615/interjenercleanenv.2020034698

Cited by 6 publications

(5 citation statements)

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“…As previously mentioned, three types of charcoals obtained from the pyrolysis process performed on Pinus pinaster, Acacia dealbata, and Cytisus scoparius pellets were used in these combustion tests. The chars were burned at two different temperatures, 700 and 800 • C, using three different particle sizes-the same average sizes previously used in the fluidized bed and stationary fixed-bed combustion studies conducted by the same team [32]. For Cytisus scoparius chars, tests were also conducted at 750 • C.…”

Section: Resultsmentioning

confidence: 99%

“…Based on this model, Pinho et al [31], in a preliminary theoretical-practical analysis that led to the present study, developed a mathematical model for char combustion in a fixed bed, where kinetic phenomena are considered. By applying this model to the combustion tests in a traveling fixed bed, and based on the kinetic information obtained from fluidized bed combustion experiments conducted by the same research team [32], it was possible to determine the bypass factor, which is the characteristic diffusive parameter of the process.…”

Section: Combustion Modelmentioning

confidence: 99%

“…The kinetic and diffusive parameters, which characterize the combustion reactions of the translational fixed-bed combustion, were obtained based on the knowledge previously acquired in the burning of char loads in fluidized beds and stationary fixed beds. The kinetic information used in this analysis, specifically the heterogeneous reaction rate constant, was obtained from previous work [32].…”

Section: Kinetic and Diffusive Datamentioning

confidence: 99%

“…Xe w = 1.564 × 10 −3 Re 3.5 (6) The obtained values for Sherwood numbers and the utilized heterogeneous reaction rate constant [32] are presented in Tables 3-5 for Pinus, Acacia, and Cytisus, respectively.…”

Section: Kinetic and Diffusive Datamentioning

confidence: 99%

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The Experimental Analysis of Biochar Combustion in a Traveling Grate Furnace

Ferreira,

Paiva,

Pinho

2024

Fire

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The current energy policy targets reducing energy dependence and minimizing pollutant emissions. Therefore, with the growing interest in using biomass as an alternative energy source, conducting scientific studies on its behavior and optimizing the respective conversion systems has become imperative. The present study focuses on investigating the combustion of biochar pellets in a laboratory-scale traveling grate furnace at three different bed temperatures: 700, 750, and 800 °C. The biochars were obtained via the carbonization process of Pinus pinaster, Acacia dealbata, and Cytisus scoparius pellets. The biochar combustion was studied using a moving-bed carbon particle burning model, supported by kinetic information which was obtained via the combustion of the same biochars in a bubbling fluidized bed. The diffusive parameter which was representative of this traveling grate combustion technology was determined, particularly the bed bypass factor. The combustion tests were carried out with the incomplete combustion of the char pellets. In general, the increase in biochar size led to a decrease in the bypass factor. However, the furnace temperature did not influence this parameter.

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Section: Resultsmentioning

confidence: 99%

Section: Combustion Modelmentioning

confidence: 99%

Section: Kinetic and Diffusive Datamentioning

confidence: 99%

Section: Kinetic and Diffusive Datamentioning

confidence: 99%

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The Experimental Analysis of Biochar Combustion in a Traveling Grate Furnace

Ferreira,

Paiva,

Pinho

2024

Fire

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“…Predominantly, kinetic study of gasification has been conducted under a chemically controlled zone at temperatures between 700 o C and 900 o C (Tanner and Bhattacharya, 2016). It is commonly believed that the kinetic parameter calculated from the chemically controlled zone is capable of describing pore diffusion phenomena happened under high-temperature zone (Ferreira et al, 2020;Kim et al, 2014). However, the optimum experimental conditions to determine kinetic pa-…”

Section: Introductionmentioning

confidence: 99%

Effect of Pore Diffusion on the Gasification Characteristics of Coal Char Under Co2 Atmosphere

Shahabuddin

Kibria

Bhattacharya

2021

Inter J Ener Clean Env

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The effect of pore diffusion on kinetic parameters is of particular interest to the current study using coal char under CO2 gasification conditions. A high-temperature entrained-flow gasifier was used for the preparation of char through the rapid pyrolysis process. The kinetic study with the char was then carried at temperatures of 973-1473 K under atmospheric pressure. A prediction of carbon conversion for large particle size (100 µm) is reported from the carbon conversion of small particle size (25 µm) considering the diffusion effect. The effect of diffusion caused by temperatures and particle size was reported through activation energy. The apparent activation energy in the chemically controlled region (973-1173 K) was calculated to be 178 kJ/mol, whereas it was 69 kJ/mol in the pore diffusion zone (1373-1473 K) using smaller particle size. The apparent activation energy using large particle size was found to be 186 and 99 kJ/mol in chemically controlled and pore diffusion zone, respectively. The intrinsic activation energy for both particle sizes was almost similar. A variation between apparent and intrinsic reaction rates was depicted mostly at higher temperatures of over 1273 K. The change in the surface area of char particle was crucial in terms of decreasing reaction rates, which was decreased with the progression of the conversion. The predicted carbon conversion for large particle size was in good agreement with the experimentally measured conversion except for little discrepancies at higher temperatures.

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