Investigation of the flash pyrolysis of some coals

Desypris, John; Murdoch, Patricia; Williams, Alan

doi:10.1016/0016-2361(82)90307-6

Cited by 51 publications

(10 citation statements)

References 17 publications

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“…Moreover, the ratio V’/VM, where V’ represents the experimental volatile matter yield, excluding tar and hydrocarbons other than methane, and VM stands for the proximate volatile matter content, is about 0.90. This value is in agreement with previous works that were obtained from fluidized reactor experiments …”

Section: Resultssupporting

confidence: 94%

“…Total devolatilization of coal can be represented by the following overall single‐reaction model:

Coal \to {bold-italicy}_{dev} V + true(1 - {bold-italicy}_{dev} true) S

where V equals total volatile yield and S equals char. The assumed first‐order rate can be expressed as follows in Equation :

\frac{bold-italicd true(y_{bold-italicdev} true)}{bold-italicdt} = r_{bold-italicdev} = k_{0, bold-italicdev} e^{- \frac{E_{d e v}}{bold-italicRT}} true(1 - y_{bold-italicdev} true); y_{bold-italicdev} = \frac{w_{0} - boldw true(t true)}{w_{0} - w_{\infty}}

where

y_{d e v}

represents the yield of devolatilization up to time t, and

w_{0}, w true(t true), w_{\infty}

stand for the initial, the instantaneous, and the final weight of coal, respectively.…”

Section: Kinetic Modellingmentioning

confidence: 99%

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Coal pyrolysis and gasification in a fluidized bed thermogravimetric analyzer

Samih

Chaouki

2018

Can J Chem Eng

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The kinetics and modelling of coal gasification were studied in the newly developed fluidized bed thermogravimetric analyzer. The total weight loss obtained from the fluidized bed reactor and the total gas product are in general agreement. The presented model for the micro‐fluidized bed reactor encompasses the kinetics of coal pyrolysis as well as the gasification reactions. For coal pyrolysis, the resulting activation energies for the individual gases were 34.7 to 59.8 kcal/mol. These values are 19 to 21 % lower than those found in the literature for similar coals. This decrease of the activation energies of the endothermic pyrolysis reactions is attributed to a gradient of temperature of 185 to 209 °C. The obtained activation energy for the CO shift reaction is 46.6 kcal/mol, increasing by 20 % from the one used in the literature. This increase of the activation energy of such a mildly exothermic reaction represents an equivalent of 170 °C gradient of temperature. The effects of temperature on the yield and the composition of the gas product are studied. Experimental results and equilibrium data are also compared. The model shows reasonably good agreement with the experimental results, except for the water gas shift reaction.

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Section: Resultssupporting

confidence: 94%

“…Total devolatilization of coal can be represented by the following overall single‐reaction model:

Coal \to {bold-italicy}_{dev} V + true(1 - {bold-italicy}_{dev} true) S

where V equals total volatile yield and S equals char. The assumed first‐order rate can be expressed as follows in Equation :

\frac{bold-italicd true(y_{bold-italicdev} true)}{bold-italicdt} = r_{bold-italicdev} = k_{0, bold-italicdev} e^{- \frac{E_{d e v}}{bold-italicRT}} true(1 - y_{bold-italicdev} true); y_{bold-italicdev} = \frac{w_{0} - boldw true(t true)}{w_{0} - w_{\infty}}

where

y_{d e v}

represents the yield of devolatilization up to time t, and

w_{0}, w true(t true), w_{\infty}

stand for the initial, the instantaneous, and the final weight of coal, respectively.…”

Section: Kinetic Modellingmentioning

confidence: 99%

Coal pyrolysis and gasification in a fluidized bed thermogravimetric analyzer

Samih

Chaouki

2018

Can J Chem Eng

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“…These values agree with the results of high temperature pyrolysis of coal fines which give R-factor of 0.75-1.36 (Anthony and Howard, 1976). They may also be compared with the values of 1.1-1.5 reported by Desypris et al (1982) …”

Section: Phenomenasupporting

confidence: 90%

Devolatilization and combustion of large coal particles in a fluidized bed

1990

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Devolatihdtion and combustion of large particles of Eastern Canadian coals (Evans and Minto), 5-50 mm dia., were studied in a bench-scale atmospheric fluidized bed reactor at 1023-1 173 K with 0.5 mm sand particles as the bed material. The devolatilization time, mass loss history, changes in proximate volatiles content and C/H mass ratio, and temperature history at the centre of the particle during devolatilization were determined. The mass loss during devolatilization is correlated with the proximate volatiles content of the parent coal. The devolatilization time is correlated with the initial particle diameter by a power-law relation with an exponent of 1.54-1.64. The results show insignificant effect of superficial velocity on devolatilization.On a CtudiC la dtvolatilisation et la combustion de larges particules de charbon de I'Est du Canada (Evans et Minto), dc 5 a 50 mm de diamktre, dans un reacteur B lit fluidis6 atmospherique de laboratoire, 2i des tempkratures de 1023 a I173 K et avec des particules de sable de 0,5 rnm de diamhre comme matCriau du lit. On a determine le temps de devolatilisation, l'histoire de la perte de masse, les changements dans la teneur des volatils voisins et le bilan massique C/H ainsi que I'histoire de la temperature au centre de la particule durant la dbvolatilisation. La perte de charge durant la dkvolatilisdtion est corrClCe ? i la teneur des volatils voisins d'un chdrbon apparentk. Le temps de dtvolatilisation est corrCIC au diamktre initial des particules par une relation de loi de puissance avec un exposant de 134-I ,64. Les rtsultats montrent un effet non significatif de la vitesse superficielle sur la devolatilisation.

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“…These observations comply with the fact that biomass fuel contains more volatiles and has higher reactivity to pyrolyze. Furthermore, the results are in general agreement with the finding of Desypris et al 15 who tested pyrolysis of a kind of 44 lm coal in a 15 mm i.d. fluidized bed reactor.…”

Section: Pyrolysis Of Coal In Mfbrasupporting

confidence: 93%

Kinetics and mechanism of solid reactions in a micro fluidized bed reactor

Yue

Liu

et al. 2010

AIChE Journal

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A novel gas-solid Micro Fluidized Bed Reaction Analyzer (MFBRA) was developed to deduce reaction rates and kinetic parameters through measuring time-dependent composition changes of evolved gases from the reactions. Application of the MFBRA to the decomposition of CaCO 3 powder resulted in an apparent activation energy of 142.73 kJ/mol and a pre-exponential factor of 399,777 s À1. This apparent activation energy was much lower than the thermogravimetry-measured value of 184.31 kJ/mol, demonstrating a quicker reaction in the MFBRA. This was further verified by CuO reduction in CO, as accelerated by the fast diffusion and high heating rate in the MFBRA. Measurement of pyrolysis of coal and biomass in MFBRA found that the reaction process was completed in about 10 s, a time much shorter than the literaturereported values in larger fluidized bed reactors. By monitoring the release of gas species from reactions at different temperatures, the MFBRA also allowed deeper insight into the mechanism of pyrolysis reactions. V

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Investigation of the flash pyrolysis of some coals

Cited by 51 publications

References 17 publications

Coal pyrolysis and gasification in a fluidized bed thermogravimetric analyzer

Coal pyrolysis and gasification in a fluidized bed thermogravimetric analyzer

Devolatilization and combustion of large coal particles in a fluidized bed

Kinetics and mechanism of solid reactions in a micro fluidized bed reactor

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