Control of Molecular Composition of Tar by Secondary Reaction in Fluidized-Bed Pyrolysis of a Subbituminous Coal

Hayashi Jun-Ichiro, Tsutomu Kawakami, Tomohiro Taniguchi, Katsuki Kusakabe, Shigeharu Morooka, Morio Yumura

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Changes in the molecular structure of tar are investigated in a fluidized-bed reactor divided into two regions: a dense bed for the primary reaction and a freeboard for the secondary reaction in the gas phase. The temperature in the dense bed is kept at 600 °C and that in the freeboard is varied in the range of 600–900 °C. A pulverized subbituminous coal (C = 76 wt %) is continuously fed into the dense bed, and tar is recovered at the reactor outlet. The tar is separated by solvent extraction into preasphaltene and asphaltene. The asphaltene is further classified by column chromatography into saturates, aromatics, phenolic ethers, nitrogen-containing compounds, and hydroxylic compounds. The aromatics are fractionated by HPLC on the basis of the number of double bonds per molecule (db) into dicyclic (5 db), dicyclic (6 db), tricyclic (7 db), tetracyclic (8 db), tetracyclic (9 db), pentacyclic (10 db), and pentacyclic and greater (+11 db) PAHs (polycyclic aromatic hydrocarbons). Each homologue is characterized by FIMS and 1H NMR to determine molar yield, number-based distribution of aliphatic carbons per molecule, and number-based distribution of α-, β-, and γ-carbons per molecule. At freeboard temperatures of 600–700 °C, detachment of aliphatic substituents proceeds with bond cleavage at aryl-α positions rather than α-β and remote positions. Decomposition of α-methyl groups is not observed below 700 °C. At a freeboard temperature of 600 °C, PAHs with three to four aliphatic carbons per molecule are most abundant, and the mole fraction of unsubstituted PAHs is only ca. 5% for each homologue. At 900 °C, however, the fraction of unsubstituted PAHs is more than 50%. The structural distribution in pyrolysis products is thus controlled by changing the freeboard temperature.

Original languageEnglish
Pages (from-to)57-66
Number of pages10
JournalEnergy and Fuels
Volume7
Issue number1
DOIs
Publication statusPublished - Jan 1 1993

Fingerprint

Tars
Coal
Polycyclic Aromatic Hydrocarbons
Tar
Polycyclic aromatic hydrocarbons
Fluidized beds
Pyrolysis
Molecules
Carbon
Chemical analysis
Temperature
Column chromatography
Ethers
Solvent extraction
Molecular structure
Nitrogen
Gases
Nuclear magnetic resonance
Decomposition
asphaltene

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology

Cite this

Control of Molecular Composition of Tar by Secondary Reaction in Fluidized-Bed Pyrolysis of a Subbituminous Coal. / Jun-Ichiro, Hayashi; Kawakami, Tsutomu; Taniguchi, Tomohiro; Kusakabe, Katsuki; Morooka, Shigeharu; Yumura, Morio.

In: Energy and Fuels, Vol. 7, No. 1, 01.01.1993, p. 57-66.

Research output: Contribution to journalArticle

Jun-Ichiro, Hayashi ; Kawakami, Tsutomu ; Taniguchi, Tomohiro ; Kusakabe, Katsuki ; Morooka, Shigeharu ; Yumura, Morio. / Control of Molecular Composition of Tar by Secondary Reaction in Fluidized-Bed Pyrolysis of a Subbituminous Coal. In: Energy and Fuels. 1993 ; Vol. 7, No. 1. pp. 57-66.
@article{be910565e12344da81169425b85835b2,
title = "Control of Molecular Composition of Tar by Secondary Reaction in Fluidized-Bed Pyrolysis of a Subbituminous Coal",
abstract = "Changes in the molecular structure of tar are investigated in a fluidized-bed reactor divided into two regions: a dense bed for the primary reaction and a freeboard for the secondary reaction in the gas phase. The temperature in the dense bed is kept at 600 °C and that in the freeboard is varied in the range of 600–900 °C. A pulverized subbituminous coal (C = 76 wt {\%}) is continuously fed into the dense bed, and tar is recovered at the reactor outlet. The tar is separated by solvent extraction into preasphaltene and asphaltene. The asphaltene is further classified by column chromatography into saturates, aromatics, phenolic ethers, nitrogen-containing compounds, and hydroxylic compounds. The aromatics are fractionated by HPLC on the basis of the number of double bonds per molecule (db) into dicyclic (5 db), dicyclic (6 db), tricyclic (7 db), tetracyclic (8 db), tetracyclic (9 db), pentacyclic (10 db), and pentacyclic and greater (+11 db) PAHs (polycyclic aromatic hydrocarbons). Each homologue is characterized by FIMS and 1H NMR to determine molar yield, number-based distribution of aliphatic carbons per molecule, and number-based distribution of α-, β-, and γ-carbons per molecule. At freeboard temperatures of 600–700 °C, detachment of aliphatic substituents proceeds with bond cleavage at aryl-α positions rather than α-β and remote positions. Decomposition of α-methyl groups is not observed below 700 °C. At a freeboard temperature of 600 °C, PAHs with three to four aliphatic carbons per molecule are most abundant, and the mole fraction of unsubstituted PAHs is only ca. 5{\%} for each homologue. At 900 °C, however, the fraction of unsubstituted PAHs is more than 50{\%}. The structural distribution in pyrolysis products is thus controlled by changing the freeboard temperature.",
author = "Hayashi Jun-Ichiro and Tsutomu Kawakami and Tomohiro Taniguchi and Katsuki Kusakabe and Shigeharu Morooka and Morio Yumura",
year = "1993",
month = "1",
day = "1",
doi = "10.1021/ef00037a011",
language = "English",
volume = "7",
pages = "57--66",
journal = "Energy & Fuels",
issn = "0887-0624",
publisher = "American Chemical Society",
number = "1",

}

TY - JOUR

T1 - Control of Molecular Composition of Tar by Secondary Reaction in Fluidized-Bed Pyrolysis of a Subbituminous Coal

AU - Jun-Ichiro, Hayashi

AU - Kawakami, Tsutomu

AU - Taniguchi, Tomohiro

AU - Kusakabe, Katsuki

AU - Morooka, Shigeharu

AU - Yumura, Morio

PY - 1993/1/1

Y1 - 1993/1/1

N2 - Changes in the molecular structure of tar are investigated in a fluidized-bed reactor divided into two regions: a dense bed for the primary reaction and a freeboard for the secondary reaction in the gas phase. The temperature in the dense bed is kept at 600 °C and that in the freeboard is varied in the range of 600–900 °C. A pulverized subbituminous coal (C = 76 wt %) is continuously fed into the dense bed, and tar is recovered at the reactor outlet. The tar is separated by solvent extraction into preasphaltene and asphaltene. The asphaltene is further classified by column chromatography into saturates, aromatics, phenolic ethers, nitrogen-containing compounds, and hydroxylic compounds. The aromatics are fractionated by HPLC on the basis of the number of double bonds per molecule (db) into dicyclic (5 db), dicyclic (6 db), tricyclic (7 db), tetracyclic (8 db), tetracyclic (9 db), pentacyclic (10 db), and pentacyclic and greater (+11 db) PAHs (polycyclic aromatic hydrocarbons). Each homologue is characterized by FIMS and 1H NMR to determine molar yield, number-based distribution of aliphatic carbons per molecule, and number-based distribution of α-, β-, and γ-carbons per molecule. At freeboard temperatures of 600–700 °C, detachment of aliphatic substituents proceeds with bond cleavage at aryl-α positions rather than α-β and remote positions. Decomposition of α-methyl groups is not observed below 700 °C. At a freeboard temperature of 600 °C, PAHs with three to four aliphatic carbons per molecule are most abundant, and the mole fraction of unsubstituted PAHs is only ca. 5% for each homologue. At 900 °C, however, the fraction of unsubstituted PAHs is more than 50%. The structural distribution in pyrolysis products is thus controlled by changing the freeboard temperature.

AB - Changes in the molecular structure of tar are investigated in a fluidized-bed reactor divided into two regions: a dense bed for the primary reaction and a freeboard for the secondary reaction in the gas phase. The temperature in the dense bed is kept at 600 °C and that in the freeboard is varied in the range of 600–900 °C. A pulverized subbituminous coal (C = 76 wt %) is continuously fed into the dense bed, and tar is recovered at the reactor outlet. The tar is separated by solvent extraction into preasphaltene and asphaltene. The asphaltene is further classified by column chromatography into saturates, aromatics, phenolic ethers, nitrogen-containing compounds, and hydroxylic compounds. The aromatics are fractionated by HPLC on the basis of the number of double bonds per molecule (db) into dicyclic (5 db), dicyclic (6 db), tricyclic (7 db), tetracyclic (8 db), tetracyclic (9 db), pentacyclic (10 db), and pentacyclic and greater (+11 db) PAHs (polycyclic aromatic hydrocarbons). Each homologue is characterized by FIMS and 1H NMR to determine molar yield, number-based distribution of aliphatic carbons per molecule, and number-based distribution of α-, β-, and γ-carbons per molecule. At freeboard temperatures of 600–700 °C, detachment of aliphatic substituents proceeds with bond cleavage at aryl-α positions rather than α-β and remote positions. Decomposition of α-methyl groups is not observed below 700 °C. At a freeboard temperature of 600 °C, PAHs with three to four aliphatic carbons per molecule are most abundant, and the mole fraction of unsubstituted PAHs is only ca. 5% for each homologue. At 900 °C, however, the fraction of unsubstituted PAHs is more than 50%. The structural distribution in pyrolysis products is thus controlled by changing the freeboard temperature.

UR - http://www.scopus.com/inward/record.url?scp=0027152317&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027152317&partnerID=8YFLogxK

U2 - 10.1021/ef00037a011

DO - 10.1021/ef00037a011

M3 - Article

VL - 7

SP - 57

EP - 66

JO - Energy & Fuels

JF - Energy & Fuels

SN - 0887-0624

IS - 1

ER -