A comprehensive experimental procedure for CO2 coal gasification: Is there really a maximum reaction rate?

Gomez, Arturo; Silbermann, Rico; Mahinpey, Nader

doi:10.1016/j.apenergy.2014.02.077

Cited by 50 publications

(25 citation statements)

References 23 publications

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“…Despite this, calculating the maximum reaction rate is still problematic. Indeed, some researchers reported about the nonexistence of the maximum reaction rate and it is just a consequence of dispersion of the gases in the reaction chamber when reacting gases being changed, especially for highly reactive char, and nothing related to char reactivity . In our study, we have experienced this behavior when a high gasification temperature was used, particularly above 820°C, which is completely compatible with the findings of Gomez et al Consequently, despite RPM fitting gives slightly higher R 2 values than SCM, values of the reaction rate constant ( k ) from SCM were utilized to calculate Arrhenius parameters as SCM is simple model and nothing of concern about maximum reaction rate.…”

Section: Resultssupporting

confidence: 91%

Influence of torrefaction after densification on the fuel characteristics and the inherited gasification kinetics of Erianthus arundinaceus energy grass

Qadi

Kobayashi

Takeno

2019

Env Prog and Sustain Energy

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In this study, a mixture of breeding lines of Erianthus arundinaceus energy grass was pretreated prior to gasification. Although biomass torrefaction and subsequent pelletizing of torrefied biomass (TOP process) have been studied in details, the torrefaction of pellets (TAP process) still in its infancy. Therefore, samples prepared by TAP, torrefaction‐only and pelletizing‐only were compared in terms of fuel characteristics and gasification kinetics. Results showed that the mass yield decreased with increasing torrefaction temperature, whereas the higher heating value (HHV) continued to increase with temperature, which can be seen in the evolution of O/C and H/C atomic ratios. Tradeoff between mass yield and HHV points to 250°C as the optimum torrefaction temperature, as mass yield above 76% could be achieved. TAP process was superior not only in terms of producing fuel with higher energy density, but also the gasification reactivity was higher than that of torrefied‐only or densified‐only samples, suggesting TAP is promising to be employed within the gasification process. Yet, conducting TAP under higher torrefaction temperatures may weaken the reactivity due to the more release of potassium during pyrolysis. Lastly, gasification kinetics data revealed that the pretreated samples exhibited slightly higher activation energy.

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Section: Resultssupporting

confidence: 91%

Influence of torrefaction after densification on the fuel characteristics and the inherited gasification kinetics of Erianthus arundinaceus energy grass

Qadi

Kobayashi

Takeno

2019

Env Prog and Sustain Energy

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“…The oak and spruce chars prepared at 800 • C were 106 and 3 times more reactive respectively in 100 % CO 2 atmosphere than the chars in 20 % CO 2 gasification, indicating a major influence of CO 2 concentration on the char reactivity. The decrease in CO 2 concentration leads to the decrease in maximum reaction rate [84,85]. In the present work, the linear correlation between reaction rate and partial pressure could not be established based on the experimental results (Table S -4) and calculations in the supplemental material (equation 3).…”

Section: Discussionmentioning

confidence: 56%

Characterization and reactivity of charcoal from high temperature pyrolysis (800–1600 °C)

Surup

Nielsen

Heidelmann

et al. 2019

Fuel

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This study presents the effect of wood origin and heat treatment temperature on the CO 2 reactivity, nanostructure and carbon chemistry of chars prepared at 800, 1200, and 1600 • C in slow pyrolysis reactors. The structure of charcoal was characterized by transmission electron microscopy, Raman spectroscopy, mercury intrusion porosimetry and N 2 adsorption. The CO 2 reactivity of char was investigated by thermogravimetric analysis. Results showed that spruce and oak chars have similar reactivity at all heat treatment temperatures.The oak char prepared at 1600 • C contained long and flat graphene layers and interplanar distance that is similar to graphite and thus, was more ordered than the spruce char. The TEM analysis showed that charcoal had structural characteristics of non-graphitizing carbon. Thus, increasing heat treatment temperature increases the graphitization of char structure, leading to the reactivity that is nearly similar to that of low reactive metallurgical coke.

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“…Gomez et al. concluded that the maximum reaction rate only depended on gas dispersion and not on the properties of char . Bai et al.…”

Section: Introductionmentioning

confidence: 99%

“…[8] Gomez et al concluded that the maximum reaction rate only depended on gas dispersion and not on the properties of char. [9] Bai et al reported that char prepared under argon was more reactive than that under carbon dioxide. [10] Liu et al studied the reactionso fB inxian chars with CO 2 at 1273-1573 Ku nder atmospheric pressure to determinet he effect of temperature and the structure of chars on the gasification process.…”

Section: Introductionmentioning

confidence: 99%

Influence of Reactant Atmospheres and Temperature on Mechanism of Gasification of Coal Char Derived from Lignite

Wang

Luo

et al. 2016

Energy Tech

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The structural characteristics and reactivity of char derived from lignite were studied to explore the mechanism of char gasification and existence of a maximum reaction rate under an atmosphere of CO2 and H2O in a pressured thermogravimetric analyzer system. Gasification was carried out at temperatures of 1123, 1173, and 1223 K. When the temperature was below 1173 K, the mechanism of char gasification in the mixture of H2O and CO2 proceeded through the separate active sites assumption, whereas if the temperature was higher than 1173 K, it favored common active sites. The reaction rate increased and then decreased during the remaining time, which was in agreement with the total surface area. The existence of a maximum reaction rate depended highly on the surface area: a larger surface area resulted in a higher reaction rate. The total surface in H2O was the largest and the addition of CO2 inhibited the formation of pores. The reaction of char with CO2 mainly took place on the microporous surface first, and then took place on a mesoporous surface, and the reaction of char with H2O took place on both the micro‐ and mesoporous surfaces simultaneously.

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A comprehensive experimental procedure for CO2 coal gasification: Is there really a maximum reaction rate?

Cited by 50 publications

References 23 publications

Influence of torrefaction after densification on the fuel characteristics and the inherited gasification kinetics of Erianthus arundinaceus energy grass

Influence of torrefaction after densification on the fuel characteristics and the inherited gasification kinetics of Erianthus arundinaceus energy grass

Characterization and reactivity of charcoal from high temperature pyrolysis (800–1600 °C)

Influence of Reactant Atmospheres and Temperature on Mechanism of Gasification of Coal Char Derived from Lignite

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A comprehensive experimental procedure for CO2 coal gasification: Is there really a maximum reaction rate?

Cited by 50 publications

References 23 publications

Influence of torrefaction after densification on the fuel characteristics and the inherited gasification kinetics of Erianthus arundinaceus energy grass

Influence of torrefaction after densification on the fuel characteristics and the inherited gasification kinetics of Erianthus arundinaceus energy grass

Characterization and reactivity of charcoal from high temperature pyrolysis (800–1600 °C)

Influence of Reactant Atmospheres and Temperature on Mechanism of Gasification of Coal Char Derived from Lignite

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Characterization and reactivity of charcoal from high temperature pyrolysis (800–1600 °C)