Experimental and numerical investigation of tar destruction under partial oxidation environment

Su, Yi; Luo, Yonghao; Chen, Yi; Wu, Wenzhi; Zhang, Yunliang

doi:10.1016/j.fuproc.2011.03.013

Cited by 58 publications

(49 citation statements)

References 44 publications

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“…Therefore, tar control or removal measures are essential for the successful implementation of gasification technology, in terms of producing clean fuel gas as well as easy control and continuous operation [12,13]. Several methods have been reported [14] to remove tar both physically [15,16] and chemically [4,[16][17][18][19][20][21]. Noncatalytic partial oxidation for vapor-phase reforming is a promising technique that can reduce the amount of tar [4,[21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…Several methods have been reported [14] to remove tar both physically [15,16] and chemically [4,[16][17][18][19][20][21]. Noncatalytic partial oxidation for vapor-phase reforming is a promising technique that can reduce the amount of tar [4,[21][22][23][24]. Su et al [21], who found that oxygen significantly impacts the conversion of tar and non-condensable gases, developed a flow reactor to predict tar destruction under partial oxidation conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Noncatalytic partial oxidation for vapor-phase reforming is a promising technique that can reduce the amount of tar [4,[21][22][23][24]. Su et al [21], who found that oxygen significantly impacts the conversion of tar and non-condensable gases, developed a flow reactor to predict tar destruction under partial oxidation conditions. Indeed, Hosokai et al investigated the gas-phase partial oxidation of nascent volatiles from the rapid pyrolysis of cedar sawdust in two-stage reactor and claimed that the amount of O 2 and the temperature were critical parameters for controlling tar concentrations [4].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetic modeling of non-catalytic partial oxidation of nascent volatiles derived from fast pyrolysis of woody biomass with detailed chemistry

Thimthong

Appari

Tanaka

et al. 2015

Fuel Processing Technology

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The gas-phase partial oxidation (POx) of nascent volatiles (NV) derived from the fast pyrolysis of cedar sawdust at 700 and 800 o C was studied both numerically and experimentally. A detailed chemical kinetic model (DCKM) was applied to simulate the POx in a two-stage reactor: the first stage was designed for fast biomass pyrolysis and the second effected the POx of the NV. Analytical pyrolysis experiments were also conducted to approximate the molecular composition of the NV, which is required input for computations using DCKM. The DCKM was modified by an empirical kinetic model for the decomposition of an ill-defined portion of the NV. The kinetic model coupled with a plug-flow reactor model reproduced the observed trends in the product yields with respect

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetic modeling of non-catalytic partial oxidation of nascent volatiles derived from fast pyrolysis of woody biomass with detailed chemistry

Thimthong

Appari

Tanaka

et al. 2015

Fuel Processing Technology

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“…Moreover, the quantitative method has been improved in analyzing yields of tar, especially one ring aromatics as benzene and toluene, which are not or partly detected in our previous work. 14,20,21 In order to reduce these one ring aromatics mass loss effects in the gravimetric tar preparation process, the collected tar solvent is promptly analyzed by GC/MS before the evaporation procedure of gravimetric tar preparation. Nascent tar represents pyrolysis tar yields in the pyrolysis stage reactor with little secondary reactions in this work, and it is more accurate in simulating the raw pyrolysis tar compounds than model tar species.…”

Section: Introductionmentioning

confidence: 99%

Nascent Biomass Tar Evolution Properties under Homogeneous/Heterogeneous Decomposition Conditions in a Two-Stage Reactor

Luo

et al. 2011

Energy Fuels

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In order to study the mechanism of biomass tar formation and elimination in a two-stage downdraft gasifier, the nascent rice straw pyrolysis tar evolution properties under homogeneous/heterogeneous decomposition conditions have been investigated in a constructed lab-scale two-stage reactor by varying factors as temperature, concentration and reforming agents of CO 2 /H 2 O/O 2 , and char bed heights. The nascent tar was produced in the first stage reactor and then decomposed in the second stage with different reforming agents or char beds. In the first stage, the results showed that nascent pyrolysis tar yields increased with increasing pyrolysis temperature, tar was mainly produced during 200À400°C, and 400À500°C would be a proper pyrolysis temperature range in commercial operation due to little effect on tar yields in higher temperature. In the second stage, it can be observed that nascent biomass tar was converted into polycyclic aromatic hydrocarbons (PAHs) (even soot), thermally stable one ring aromatics, and noncondensable gases in homogeneous conditions with increasing temperature. Different effects were obtained in varying tar species under different homogeneous reforming agents. However, benzene, toluene, styrene, phenol, and naphthalene are the most typical compounds, accounting for 50À75% in total tar concentration at 900°C in all decomposition conditions. Char bed can selectively reduce PAH species remarkably and increase the toluene yields. As for the three reforming agents, steam showed the highest efficiency in tar elimination, while CO 2 and O 2 present will induce OH, H, and O radicals formation, which increases hydrocarbon conversion. The mechanism of tar destruction in a two-stage downdraft gasifier can be concluded as follows: nascent tar yields from the pyrolysis stage will be first reformed into PAHs, thermally stable one ring aromatics and noncondensable gases in the throat region, and then PAHs species are almost completely decomposed by the char bed, which are the main troublesome tar components in syngas, and finally the syngas with low tar was obtained.

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“…This is relatively high when compared to other studies. 11,14,15 If the flow rate of air to the CTC was decreased, the flame would become unstable and extinguish. The flame stability issue would be improved if the supply of tarry gas to the CTC was at a constant rate.…”

Section: Resultsmentioning

confidence: 99%

Destruction of Tar in a Novel Coandă Tar Cracking System

2014

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The main objective of this research program was to develop and test a small-scale system that used a novel Coandăburner for tar destruction through partial oxidation. An experimental rig consisting of a tar injector, in which wood pellets were pyrolyzed, and a Coandătar cracking unit was designed, constructed, and operated to determine the effectiveness of the unit. The experimental program was divided into two phases, so that comparisons of the tar composition with and without treatment could be made. In the first phase, wood pellets were pyrolyzed at a range of temperatures between 500 and 800°C and the pyrolysis products (gas, tar, and char) were analyzed. Increasing the temperature from 500 to 700°C caused an increase in the production of hydrogen, methane, and carbon dioxide. As the pyrolysis temperature increased from 500 to 800°C, there was a decrease in the yield of gravimetric tar in the sampled gas from 67.2 to 15.7 g/nm 3 . This reduction can be attributed to higher pyrolysis temperature, causing an increase in thermal cracking and depolymerization reactions, which, in turn, promotes production of permanent gas species. In the second phase, the gas produced in the first phase was treated in sub-stoichiometric conditions in the Coandătar cracker. When the yield of tar species found in the treated and untreated gases is compared when the pyrolysis temperature of the tar injector was set at 800°C, benzene was reduced by 95%, toluene was reduced by 96%, naphthalene was reduced by 97.7%, and the gravimetric tar yield was reduced by 86.7%. The Coandătar cracker was shown to be effective at significantly reducing the tar content in the product gas. The reduction can be attributed to the high flame temperature (>1000°C) and the addition of oxygen, which leads to the formation of free radicals, causing tar destruction.

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Experimental and numerical investigation of tar destruction under partial oxidation environment

Cited by 58 publications

References 44 publications

Kinetic modeling of non-catalytic partial oxidation of nascent volatiles derived from fast pyrolysis of woody biomass with detailed chemistry

Kinetic modeling of non-catalytic partial oxidation of nascent volatiles derived from fast pyrolysis of woody biomass with detailed chemistry

Nascent Biomass Tar Evolution Properties under Homogeneous/Heterogeneous Decomposition Conditions in a Two-Stage Reactor

Destruction of Tar in a Novel Coandă Tar Cracking System

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