Catalytic upgrading of gaseous tars over zeolite catalysts during coal pyrolysis

Yan, Lunjing; Kong, Xiaojun; Zhao, Ruifang; Li, Fan; Xie, Kui

doi:10.1016/j.fuproc.2015.05.030

Cited by 81 publications

(52 citation statements)

References 26 publications

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“…The content of 3‐ and 4‐ring aromatics in the upgraded tar decrease as shown in Figure e. It is suggested that 3‐ and 4‐ring aromatics go through ring‐opening reaction during tar cracking, and then combined by the active hydrogen and hydroxyl groups generated by the steam dissociation to generate benzenes, phenols and naphthalenes.…”

Section: Resultsmentioning

confidence: 99%

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts

Cao

Wang

et al. 2020

ChemistrySelect

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In-situ upgrading of coal pyrolysis tar with steam catalytic cracking (SCC) is a promising technique to improve tar quality. In this study, Ni/Al 2 O 3 catalysts with different Ni contents were used for in-situ SCC of coal pyrolysis tar at 650°C. The results showed that Ni/Al 2 O 3 catalysts can enhance the water conversion and light tar yield. Both SCC and tar catalytic cracking can occur simultaneously over Ni/Al 2 O 3 , and the free radicals produced by tar catalytic cracking can be stabilized by active species generated from SCC to avoid excessive cracking of tar and improve light tar yield. 4Ni/Al 2 O 3 (4 wt. % Ni) exhibits the best performance, contributing to the highest water conversion of 4.74 wt. % and light tar yield of 11.90 wt. %, respectively.Correspondingly, the content of light fraction (boiling point less than 360°C) in tar sample increases from 48.0 wt. % to 67.0 wt. %, and the average molecular weight decreases from 353 amu to 253 amu over 4Ni/Al 2 O 3 . This is consistent with the increase of benzenes, phenols and naphthalenes and the decrease of long-chain aliphatic hydrocarbons, 3-and 4-ring aromatics in upgraded tar. In addition, the higher ratio of uncondensed aromatic protons to condensed aromatic protons in upgraded tar reveals the fact that 4Ni/Al 2 O 3 can promote ring-opening reaction of PAHs, which can well interpret the tar upgrading process.

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Section: Resultsmentioning

confidence: 99%

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts

Cao

Wang

et al. 2020

ChemistrySelect

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“…Bakar et al evaluated rice husk for improving the hydrocarbons and light phenols in bio‐oil with the catalytic influence of HZSM‐5 zeolite 32 . Yan et al reported the upgrading of light arenes to BTX and the increase in light arenes to 130% over USY zeolite, and Kong et al observed gaseous tar upgrading on different zeolites (Y‐type) to obtain high yields of benzene, toluene, ethylbenzene, xylene, and naphthalene (BTEXN) 24,25 …”

Section: Introductionmentioning

confidence: 99%

“…Previous studies focused mostly on the gaseous tar upgrading, mostly explaining the variations of particular aromatic compounds, for example, BTX and BTEXN 21,23,25 . Nevertheless, these studies rarely described the reduction of CO 2 gas yield and the conversion of heavy coal tar to light coal tars according to the range of their boiling points.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies have examined the effectiveness of zeolite catalysts (HZSM-5, USY, and SBA-15) in the catalytic cracking of coals. 21,[23][24][25] HZSM-5 has the strongest Brønsted acid sites that promote the aromatization reaction to convert hydrocarbon materials to BTX. [26][27][28] Chareonpanich et al examined the catalytic pyrolysis of Millmerran coal using metal-loaded zeolite catalysts.…”

mentioning

confidence: 99%

“…24,25 Previous studies focused mostly on the gaseous tar upgrading, mostly explaining the variations of particular aromatic compounds, for example, BTX and BTEXN. 21,23,25 Nevertheless, these studies rarely described the reduction of CO 2 gas yield and the conversion of heavy coal tar to light coal tars according to the range of their boiling points. This study examined the effects of HZSM-5 and Mg/HZSM-5 catalysts on the yields, gas component yields, and conversion of heavy coal tar compounds at various pyrolysis temperatures.…”

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confidence: 99%

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Ex‐situ catalytic fast pyrolysis of low‐rank coal over HZSM ‐5 and modified Mg/ HZSM ‐5 catalysts

Amin

Ahmed

et al. 2021

Intl J of Energy Research

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Summary Catalytic effects in fast pyrolysis of low‐rank coal and coal tar conversion were investigated in a two‐stage fixed‐bed reactor over HZSM‐5 zeolite and Mg/HZSM‐5. Mg/HZSM‐5 caused the lower total tar yield and the higher non‐condensable gas yield but the fraction of light tar (boiling point below 360°C) increased to allow a slightly higher total yield of light tar. It also exhibited good catalytic activity and increased the species of light tar than HZSM‐5 zeolite. The light tar fraction was increased from 45 to 74.6 wt% than without catalyst (66%) at the pyrolysis temperature of 600°C. Ex‐situ catalytic fast pyrolysis over Mg/HZSM‐5 also lowered the contents of element N and S in the resulting coal tars by 29% and 15% respectively. The corresponding increase in the content of element H and molar ratio of H to C of the resulting coal tars was reported as 17% and 13% respectively. The addition of Mg into HZSM‐5 increased the ability of the catalyst for inhibiting coke deposition.

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Lignite pyrolysis with subsequent refining of volatile products in separately heated catalytic reactor

et al. 2019

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Catalytic upgrading of gaseous tars over zeolite catalysts during coal pyrolysis

Cited by 81 publications

References 26 publications

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts

Ex‐situ catalytic fast pyrolysis of low‐rank coal over HZSM ‐5 and modified Mg/ HZSM ‐5 catalysts

Lignite pyrolysis with subsequent refining of volatile products in separately heated catalytic reactor

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Catalytic upgrading of gaseous tars over zeolite catalysts during coal pyrolysis

Cited by 81 publications

References 26 publications

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al2O3 Catalysts

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al2O3 Catalysts

Ex‐situ catalytic fast pyrolysis of low‐rank coal over HZSM ‐5 and modified Mg/ HZSM ‐5 catalysts

Lignite pyrolysis with subsequent refining of volatile products in separately heated catalytic reactor

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In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts

In‐Situ Upgrading of Coal Pyrolysis Tar with Steam Catalytic Cracking over Ni/Al₂O₃ Catalysts