Characterizing rate inhibition in steam/hydrogen gasification via analysis of adsorbed hydrogen

Lussier, Michael G.; Zhang, Z.; Miller, Dennis J.

doi:10.1016/s0008-6223(98)00123-7

Cited by 99 publications

(46 citation statements)

References 23 publications

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“…The reason for this is the removal of CO and H 2 by reactions (5) and (6). The presence of H 2 during the gasification of solid fuels is well known to inhibit the reaction rate [20,21]. This inhibiting effect of H 2 has also been shown to strongly affect the conversion of char in the presence of oxygen-carrier particles in a laboratoryscale, fluidized-bed reactor [22].…”

Section: Chemical Looping Combustionmentioning

confidence: 99%

Using Low-Cost Iron-Based Materials as Oxygen Carriers for Chemical Looping Combustion

Jerndal

Leion

Axelsson

et al. 2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Résumé -Utilisation de matériaux bon marché à base de fer comme transporteur d'oxygène dans la combustion en boucle chimique -Pour appliquer la combustion en boucle chimique à des charges solides, il est important d'utiliser des matériaux transporteurs d'oxygène bon marché. En effet, la durée de vie du transporteur d'oxygène risque d'être plus courte sur charge solide que sur charge gazeuse. Ces matériaux doivent également bien convertir le monoxyde de carbone et l'hydrogène résultant de la gasification, tout en étant suffisamment durs pour résister à la fragmentation. Plusieurs matériaux ont montré un potentiel de conversion élevé sur le gaz de synthèse ainsi qu'une résistance mécanique élevée, ce qui permet d'envisager leur utilisation lors des développements futurs de la technologie. Parmi ces matériaux, on trouve des oxydes en copeaux provenant de Sandvik et Scana, et un minerai de fer de LKAB. Tous les matériaux testés ont permis d'atteindre des conversions plus élevées sur gaz de synthèse que le matériau de référence (ilménite) utilisé au cours de l'étude. D'une manière générale, les transporteurs d'oxygène les moins résistants, sans doute les plus poreux, sont les plus réactifs avec le gaz de synthèse. Le taux de conversion du CO obtenu avec ces matériaux est toujours plus élevé qu'avec l'ilménite. Le taux de conversion de l'hydrogène est plus élevé lorsque la durée de réduction augmente. Le matériau Sandvik 2 a permis d'atteindre les taux de conversion les plus importants sur gaz de synthèse et a donc été sélectionné pour des tests sur charge solide. Le taux de conversion sur charge solide avec ce matériau est plus élevé qu'avec l'ilménite. Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 66 (2011) Abstract, No. 2, pp. 235-248 Copyright © 2011, IFP Energies nouvelles DOI: 10.2516/ogst/2010030Chemical Looping -An Alternative Concept for Efficient and Clean Use of Fossil Resources La Boucle Chimique -Un concept alternatif pour un usage propre et efficace des ressources fossiles IFP Energies nouvelles International Conference Rencontres Scientifiques d'IFP Energies nouvellesOil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 66 (2011)

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Section: Chemical Looping Combustionmentioning

confidence: 99%

Using Low-Cost Iron-Based Materials as Oxygen Carriers for Chemical Looping Combustion

Jerndal

Leion

Axelsson

et al. 2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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“…The process has been studied by many researchers to understand the kinetics and mechanisms of both non-catalytic and catalytic reactions using fixed- (Haga and Nishiyama, 1988) and fluidized-bed reactors. H 2 is the main inhibitor in the steam gasification of char (Lussier et al, 1998;Yang and Duan, 1985); the rate of steam gasification in the presence of H 2 is lower by an order of magnitude or more than in its absence. However, recent studies (Hayashi et al, 2000(Hayashi et al, , 2002 have shown that pyrolysis-derived volatiles, including tar, are much stronger inhibitors than H 2 in the steam gasification of char, because of the volatileschar interactions.…”

Section: In Situ Steam Gasification Of Char Gasificationmentioning

confidence: 98%

Toward Low-Temperature Coal Gasification: Experimental and Numerical Studies of Thermochemical Coal Conversion Considering the Interactions between Volatiles and Char Particles

Zhang

Kudo

et al. 2017

KONA

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A novel triple-bed combined circulating fluidized-bed (TB-CFB) coal gasifier, consisting of a downer (pyrolyzer), a bubbling fluidized bed (gasifier), and a riser (combustor) was proposed for realizing low-temperature coal gasification. Several key thermochemical reactions were extracted from those expected in the downer unit: the reforming of refractory tar in both the gas phase and over the char surface, and the steam gasification of the nascent char. This review highlights our recent progress, both experimental and numerical, in studies of thermochemical coal conversion including the various reaction processes, by employing a drop-tube reactor that well approximates the reaction environment in a downer reactor. This discussion can be utilized in designing TBCFBs and optimizing their operation.

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“…Six global chemical reactions were considered in the simulation. Two homogeneous reactions (5)(6) and four heterogeneous reactions (7-10) were considered according to the developed lumped kinetic model, as follows: The boundary conditions for the numerical simulation are shown in the Supplementary Information. In addition, the convergence criteria are set in a transient fashion with a time step of 0.001 s and residuals for continuity less than 10 −4 , energy less than 10 − 6 , and all species less than 10 −6 .…”

Section: Simulation Layoutmentioning

confidence: 99%

“…Tar is an undesirable product of gasification because of various problems associated with condensation, formation of tar aerosols, and polymerization to form more complex structures, which can impede and damage the process equipment, as well as the engines and turbines used in product gas consumption [4]. Also, other volatile materials generated during coal gasification, such as light hydrocarbon gases and hydrogen may strongly inhibit char gasification [5][6][7]. Therefore, the development of technologies and methods for the reduction or removal of tar has received substantial attention in recent years [4,8,9].…”

Section: Introductionmentioning

confidence: 99%

Modeling of gas/particle flow in coal conversion with a drop tube reactor using a lumped kinetic model accounting volatiles–char interaction

Appari

Zhang

et al. 2015

Fuel Processing Technology

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a b s t r a c tCoal conversion including reforming of nascent tar over the char surface in a drop tube reactor (DTR) was studied both experimentally and numerically. Victorian brown coal and char prepared from the same coal were co-fed into an atmospheric DTR. The effects of reaction temperature (973-1173 K), solid hold-up (8.31 × 10 −6 -2.50 × 10 −4 ), residence time (0-4.6 s for gas; 0-0.78 s for solid particles), and steam partial pressure (0-0.05 MPa) on the conversion characteristics were investigated. A 4-lump kinetic model consisting of tar, gases, char, and soot with 6 global reactions was developed based on the experimental results. The lumped kinetic model was integrated with a computational fluid dynamics (CFD) simulation using an Eulerian-Eulerian approach for mixed phase flow to simulate the coal conversion experiments in the DTR. The CFD results for product distribution during coal conversion in the DTR showed reasonable agreement with the experimental results. The CFD approach presented is suitable for use in designing and optimizing a pyrolyzer for a triple-bed combined circulating fluidized-bed coal gasifier, consisting of a downer (pyrolyzer), a bubbling fluidized bed (gasifier), and a riser (combustor).

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Characterizing rate inhibition in steam/hydrogen gasification via analysis of adsorbed hydrogen

Cited by 99 publications

References 23 publications

Using Low-Cost Iron-Based Materials as Oxygen Carriers for Chemical Looping Combustion

Using Low-Cost Iron-Based Materials as Oxygen Carriers for Chemical Looping Combustion

Toward Low-Temperature Coal Gasification: Experimental and Numerical Studies of Thermochemical Coal Conversion Considering the Interactions between Volatiles and Char Particles

Modeling of gas/particle flow in coal conversion with a drop tube reactor using a lumped kinetic model accounting volatiles–char interaction

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