Kinetic study of char combustion in a fluidized bed

Brunello, Somchuer; Flour, I.; Maissa, P.; Bruyet, Bernard

doi:10.1016/0016-2361(95)00305-3

Cited by 17 publications

(4 citation statements)

References 2 publications

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“…Some of the earliest gasification studies include those of Ergun [7], where coke gasification was studied extensively and the composition of syngas at various temperatures was obtained. Several studies on the combustion rate of carbon [8], the kinetics of char combustion in a fluidized bed [9], mathematical models for thermal decomposition of coal [10e14] and combustion and gasification kinetics of pyrolysis chars from waste and biomass [15] are presented in literature. All these studies focused on the devolatilization of biomass and change in weight of the initial biomass with temperature.…”

Section: Biomass Gasificationmentioning

confidence: 99%

Design of biomass and natural gas based IGFC using multi-objective optimization

Naraharisetti

Lakshminarayanan

Karimi

2014

Energy

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Section: Biomass Gasificationmentioning

confidence: 99%

Design of biomass and natural gas based IGFC using multi-objective optimization

Naraharisetti

Lakshminarayanan

Karimi

2014

Energy

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“…Common experimental devices used for exploring char combustion include thermogravimetric analysis (TGA) systems, , flame combustors, drop tube furnaces, and fluidized beds. − TGA provides thermogravimetric information with high degrees of automation and measurement resolution. However, the commonly used commercial TGA is actually a fixed-bed apparatus.…”

Section: Introductionmentioning

confidence: 99%

“…Sadhukhan et al used a basket to directly measure the sample weight in a fluidized bed; 23 however, the sample was separated from the silica sand bed material by the basket. Brunello et al obtained information on the combustion kinetics by analyzing the tail gas, 21 which could not validate the influence of backmixing and the signal delay of the tail gas species. Therefore, in the present study, a system featuring a micro-fluidized bed with thermogravimetry−mass spectrometry analyzers (denoted as MFB-TG-MS) was constructed to determine the char combustion kinetics using the on-line sample weight signal and tail gas composition, which could mutually validate the accuracy of the combustion kinetics data.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Biomass Char Combustion Kinetics Using a Micro-Fluidized Bed with Thermogravimetry–Mass Spectrometry

Wu,

Wang,

2023

Energy Fuels

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Assessing the kinetics of biomass char combustion in the fluidized state is crucial for facilitating the thermochemical utilization of biomass energy. In this study, a micro-fluidized bed integrated with thermogravimetry−mass spectrometry (denoted as MFB-TG-MS) was developed to evaluate the combustion kinetics of biomass char in the fluidized state. The constructed device enabled intense heat and mass transfer owing to the fluidization of the bed materials and biomass char samples. On-line sample weight signals and the concentration of tail gas (including O 2 , CO 2 , and CO) were obtained simultaneously in the fluidized state during the experiments. Experimental results indicated that the combustion kinetics of biomass char measured using the MFB-TG-MS system was significantly faster than that determined using a regular TG analyzer. Effects of sample sizes and bed temperatures on char combustion were analyzed. A single-film char combustion model and the Kunii−Levenspiel model were applied to describe the char combustion characteristics in the fluidized reactor. A genetic algorithm was employed to optimize certain combustion kinetic parameters: pre-exponential factor (8.51 m/s), activation energy (35.02 × 10 3 J/mol), and reaction order (0.78). The MFB-TG-MS system reported herein permits effective measurements of the rapid combustion kinetics closer to the intrinsic kinetics inside a fluidized bed reactor.

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“…Numerous studies have highlighted the limitations of thermogravimetric analyzers in maintaining isothermal and kinetically controlled reaction conditions. ,,− Use of a fluidized-bed reactor with rapid heat and mass transfer is the most efficient technique for minimizing diffusion inhibition and controlling the temperature of reactive particles. Fluidized beds have been extensively used to analyze gas–solid reactions. − Hayhurst et al − have performed much valuable research on the kinetics of char combustion using a laboratory-scale fluidized-bed reactor. Xu et al ,− developed a micro fluidized-bed reaction analyzer (MFBRA) that enabled isothermal differential investigation of gas–solid reactions.…”

Section: Introductionmentioning

confidence: 99%

Development of a Multistage in Situ Reaction Analyzer Based on a Micro Fluidized Bed and Its Suitability for Rapid Gas–Solid Reactions

et al. 2016

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An in situ decoupling analytical method was proposed and a multistage in situ reaction analyzer based on a micro fluidized bed (MFB-MIRA) was developed for in situ and on-line analysis of multistage gas−solid reaction processes. The responses of the pipe system to various gas concentration waves were analyzed. The in situ decoupled combustion properties of three coals were investigated using a two-stage reaction procedure involving devolatilization in Ar and combustion in O 2 /Ar. The Peclet number of the pipe flow was as large as 87, indicating approximate plug flow in the MFB-MIRA. A concentration correction model was built to simulate the real gas release process in the micro fluidized-bed reactor. The measurement distortions in the char combustion concentration curves were found negligible, which proved the reliability of using the measured results directly to derive the carbon conversion processes. The MFB-MIRA gives a good mass balance. The combustion reaction orders of the three in situ chars in O 2 were all about 0.9 during the main reaction period and decreased monotonously with increasing carbon conversion after the maximum rate. Calculations of heat and mass transfer during char combustion showed that isothermal reaction conditions were guaranteed and combustion during carbon conversions of 0.3−0.8 were kinetically controlled. This study proves that the MFB-MIRA is suitable for rapid gas−solid reactions.

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Kinetic study of char combustion in a fluidized bed

Cited by 17 publications

References 2 publications

Design of biomass and natural gas based IGFC using multi-objective optimization

Design of biomass and natural gas based IGFC using multi-objective optimization

Evaluation of Biomass Char Combustion Kinetics Using a Micro-Fluidized Bed with Thermogravimetry–Mass Spectrometry

Development of a Multistage in Situ Reaction Analyzer Based on a Micro Fluidized Bed and Its Suitability for Rapid Gas–Solid Reactions

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