Experimental Investigation of Tar Conversion under Inert and Partial Oxidation Conditions in a Continuous Reactor

Wu, Wenzhi; Luo, Yonghao; Chen, Yi; Su, Yi; Zhang, Yunliang; Zhao, Shanhui; Wang, Yun

doi:10.1021/ef200297s

Cited by 21 publications

(18 citation statements)

References 18 publications

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“…The increase in methane as the pyrolysis temperature increased can be attributed to the decomposition of methoxyl groups. 11 Hydrogen is generated by the dehydrogenation of char, tar, and hydrocarbons. Table 2 shows the effect of the temperature on the key tar species present in the collected tar.…”

Section: Resultsmentioning

confidence: 99%

“…Increasing the temperature at which thermal cracking is performed results in an increase to the heating value of the gas, which is an important characteristic to consider when evaluating the overall energy efficiency of the process. 11 Anis and Zainal 8 determined that the temperate range for tar cracking is between 700 and 1250°C. For effective decomposition, additional means are required, such as increasing the gas residence time, directly contacting the gas with an independently heated surface, or adding oxygen or steam.…”

Section: Introductionmentioning

confidence: 99%

“…High temperatures influence internal tar stability, allowing for conversion into other species; however, the energy required to reach the required temperatures is a detriment to the overall efficiency. Increasing the temperature at which thermal cracking is performed results in an increase to the heating value of the gas, which is an important characteristic to consider when evaluating the overall energy efficiency of the process . Anis and Zainal determined that the temperate range for tar cracking is between 700 and 1250 °C.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Destruction of Tar in a Novel Coandă Tar Cracking System

2014

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“…Cresol is to represent nearly approaching heavy tar and naphthalene to represent light tar [10]. Tar will experience reforming when entering the combustion and gasification zones to form H 2 and CO through the reaction of steam reforming and dry reforming [11]:…”

Section: Methodsmentioning

confidence: 99%

Thermodynamic Model for Updraft Gasifier with External Recirculation of Pyrolysis Gas

Vidian

Surjosatyo

Nugroho

2016

Journal of Combustion

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Most of the thermodynamic modeling of gasification for updraft gasifier uses one process of decomposition (decomposition of fuel). In the present study, a thermodynamic model which uses two processes of decomposition (decomposition of fuel and char) is used. The model is implemented in modification of updraft gasifier with external recirculation of pyrolysis gas to the combustion zone and the gas flowing out from the side stream (reduction zone) in the updraft gasifier. The goal of the model obtains the influences of amount of recirculation pyrolysis gas fraction to combustion zone on combustible gas and tar. The significant results of modification updraft are that the increases amount of recirculation of pyrolysis gas will increase the composition of H2and reduce the composition of tar; then the composition of CO and CH4is dependent on equivalence ratio. The results of the model for combustible gas composition are compared with previous study.

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“…Studies on lignin pyrolysis demonstrate that tar compounds undergo a progressive alteration and conversion with temperature. − An initial volatile product, generally termed “primary tar”, is first released at temperatures between 400 and 600 °C. This primary tar is a complex mixture of highly substituted oxygen-containing compounds.…”

Section: Introductionmentioning

confidence: 99%

Lumped Kinetics for Biomass Tar Cracking Using 4-Propylguaiacol as a Model Compound

Ledesma

Mullery

et al. 2015

Ind. Eng. Chem. Res.

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Lumped kinetics for the vapor-phase cracking of 4-propylguaiacol, a model compound representative of components found in primary tar derived from lignin, has been investigated. Analysis of the products from pyrolysis experiments in a laminar-flow reactor at temperatures between 300 and 900 °C and a residence time of 1 s revealed that the products can be lumped into three compound classes: oxygen-containing compounds, single- and multiring aromatic hydrocarbons, and permanent gases. Temperature was found to have a marked effect in governing the overall product composition. The oxygen-containing compounds peaked in yield between 500 and 700 °C. The aromatic hydrocarbons and permanent gases dominated the product composition above 600 °C, especially at 900 °C, the highest temperature investigated. A lumped kinetic model with three irreversible first-order reactions was developed to model the experimental data. This model was extended to one with eight first-order irreversible reactions. Optimized reaction-rate parameters for each reaction in both models were determined by fitting the experimental data using a plug-flow reactor model.

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Experimental Investigation of Tar Conversion under Inert and Partial Oxidation Conditions in a Continuous Reactor

Cited by 21 publications

References 18 publications

Destruction of Tar in a Novel Coandă Tar Cracking System

Destruction of Tar in a Novel Coandă Tar Cracking System

Thermodynamic Model for Updraft Gasifier with External Recirculation of Pyrolysis Gas

Lumped Kinetics for Biomass Tar Cracking Using 4-Propylguaiacol as a Model Compound

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