The continuous self stirred tank reactor: measurement of the cracking kinetics of biomass pyrolysis vapours

Baumlin, Sébastien; Broust, François; Ferrer, Monique; Meunier, Nicolas; Marty, Éric; Lédé, Jacques

doi:10.1016/j.ces.2004.07.057

Cited by 41 publications

(40 citation statements)

References 18 publications

(79 reference statements)

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“…The experiments show that for the same type of wood [26], the bio-oils yields (around 65%) do not significantly depend on the imposed values of 8 (between 0.85 and 0.08 MW m −2 ). Such yields are also similar in pyrolysis experiments performed in a simple hot walls tubular reactor (where values of φ may be estimated around 0.04 MW m −2 [26,38]). These results bring evidence that 8 is not a sensible parameter for FP characterization.…”

Section: Heat Flux Densitysupporting

confidence: 73%

“…For example, it is possible from Ref. [38] to estimate a vapor partial pressure of about 10 −2 atm, which is much lower than the pressure in vacuum reactors (around 0.15 atm).…”

Section: Effects Of Pressure and Dilutionmentioning

confidence: 98%

“…But the reactor controls also the extent of secondary reactions that should be minimized before the bio-oil condensation steps. These reactions include homogeneous gas phase and/or heterogenous solids (char, catalysts)/vapors crackings [26,38,56].…”

Section: Brief Overview Of Problems Connected To the Reactormentioning

confidence: 99%

“…It can, however, appear surprising that higher bio-oil yields (60-70%) can be obtained under atmospheric pressure in other devices where biomass is simply heated inside a hot walls tubular reactor fed by a high flow of inert gas [38,48]. In this last case, the mean heat transfer coefficient (convection+radiation) estimated around 50 Wm −2 K −1 [26] is still lower than in vacuum experiments.…”

Section: Effects Of Pressure and Dilutionmentioning

confidence: 99%

“…Actually, the search of optimal conditions for preventing the secondary reactions needs the optimization (minimization) of both vapor phase temperature and residence time, on the basis of reliable cracking kinetics models. Considering the only simplified case of homogeneous reactions, the kinetic constants measurements as well as the determination of reliable kinetic pathways have given rise to a substantial number of studies [38,57]. In the very simplified assumption of a simple firstorder reaction, the results show that kinetic constants may vary inside at least 2 orders of magnitudes.…”

Section: Brief Overview Of Problems Connected To the Reactormentioning

confidence: 99%

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Characterization of biomass fast pyrolysis

Lédé

Authier

2011

Biomass Conv. Bioref.

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The literature shows that different possible criteria are used for defining biomass fast pyrolysis. On the basis of a simplified modeling of a cellulose (biomass model compound) particle pyrolysis, the present paper points out that the most often considered parameters (i.e., temperature and heating rate) are inappropriate. They are very difficult to define and measure, and according to their definitions, important errors can be made (kinetic measurements and reactor scaling up). Other possible parameters are also examined such as particle initial size, available heat flux density, heat transfer coefficient, and products elimination efficiency. In order to be able to compare different experimental conditions on a similar basis, it is shown that at the biomass sample level, fast pyrolysis is favoured (enhancement of bio-oil fractions) if two necessary conditions are simultaneously fulfilled. They include high external heat transfer coefficient and efficient products removal.

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Section: Heat Flux Densitysupporting

confidence: 73%

“…For example, it is possible from Ref. [38] to estimate a vapor partial pressure of about 10 −2 atm, which is much lower than the pressure in vacuum reactors (around 0.15 atm).…”

Section: Effects Of Pressure and Dilutionmentioning

confidence: 98%

Section: Brief Overview Of Problems Connected To the Reactormentioning

confidence: 99%

Section: Effects Of Pressure and Dilutionmentioning

confidence: 99%

Section: Brief Overview Of Problems Connected To the Reactormentioning

confidence: 99%

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Characterization of biomass fast pyrolysis

Lédé

Authier

2011

Biomass Conv. Bioref.

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show abstract

Bibliography

2016

Thermochemical Conversion of Biomass for the Production of Energy and Chemicals

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Heterogeneous and homogeneous reactions of pyrolysis vapors from pine wood

Hoekstra¹,

Westerhof²,

Brilman³

et al. 2011

AIChE Journal

122

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in Wiley Online Library (wileyonlinelibrary.com).To maximize oil yields in the fast pyrolysis of biomass it is generally accepted that vapors need to be rapidly quenched. The influence of the heterogeneous and homogeneous vapor-phase reactions on yields and oil composition were studied using a fluidized-bed reactor. Even high concentrations of mineral low char (till 55 vol %) appeared not to be catalytically active. However, the presence of minerals, either in biomass or added, does influence the yields, especially by the occurrence of vapor-phase charring/polymerization reactions. Contradictory, in the absence of minerals, homogeneous vapor-phase cracking reactions were dominant over polymerization/charring reactions (400-550 C, 1-15 s). With increasing vapor residence time, the oil yield reached an asymptotic value, which decreased with temperature. At a vapor temperature of 400 C no decrease in oil yield was observed, but dedicated analysis showed that homogeneous vapor to vapor reactions had occurred. a Sigma-Aldrich, P9333, purity [ 99.0%, b Sigma-Aldrich S7795, purity [ 99.0%, c Sigma-Aldrich 23653-412 K 2 CO 3 , purity ¼ 99.0%

show abstract

The continuous self stirred tank reactor: measurement of the cracking kinetics of biomass pyrolysis vapours

Cited by 41 publications

References 18 publications

Characterization of biomass fast pyrolysis

Characterization of biomass fast pyrolysis

Bibliography

Heterogeneous and homogeneous reactions of pyrolysis vapors from pine wood

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