Intrinsic gasification kinetics of coal chars generated in a high-pressure, high-temperature flow reactor

Vijayaragavan Krishnamoorthy, Nandakumar Krishnamurthy, Sarma V. Pisupati

Research output: Contribution to journalArticle

Abstract

An understanding of the intrinsic gasification rates of chars generated at high temperatures and elevated pressures is crucial for the design and optimization of gasifiers. Therefore, a widely used Pittsburgh No. 8 coal was partially gasified in a CO2/N2 atmosphere at 1300 °C at a range of pressures (3.4, 6.2, 11.3, 15.5, and 21.7 bar) in a high-pressure, high-temperature flow reactor to generate char. The intrinsic reaction rate of those chars with CO2 was obtained using a high-pressure thermogravimetric analyzer. The kinetic parameters were obtained using an nth-order model. The results show that the intrinsic reaction rate was less affected by the char generation pressure, while the apparent reaction rate was primarily dependent on the surface area evolution during the gasification process. The apparent reactivity reached a maximum for the char generated at 6.2 bar and decreased with further increases in pressure. Among the kinetic parameters, the activation energies were not affected over the range of char generation pressures (3.4–21.7 bar), while the pre-exponential factors were within similar orders of magnitude. The order of reaction was determined by varying the CO2 partial pressure. The order of reaction decreased with increasing char generation pressure and closely followed the surface area at that conversion in most cases.

Original languageEnglish (US)
Article number122028
JournalChemical Engineering Journal
Volume375
DOIs
StatePublished - Nov 1 2019

Fingerprint

Coal
Gasification
coal
kinetics
Kinetics
reaction rate
Reaction rates
Temperature
surface area
Kinetic parameters
partial pressure
activation energy
reactor
gasification
Partial pressure
atmosphere
Activation energy

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

Cite this

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abstract = "An understanding of the intrinsic gasification rates of chars generated at high temperatures and elevated pressures is crucial for the design and optimization of gasifiers. Therefore, a widely used Pittsburgh No. 8 coal was partially gasified in a CO2/N2 atmosphere at 1300 °C at a range of pressures (3.4, 6.2, 11.3, 15.5, and 21.7 bar) in a high-pressure, high-temperature flow reactor to generate char. The intrinsic reaction rate of those chars with CO2 was obtained using a high-pressure thermogravimetric analyzer. The kinetic parameters were obtained using an nth-order model. The results show that the intrinsic reaction rate was less affected by the char generation pressure, while the apparent reaction rate was primarily dependent on the surface area evolution during the gasification process. The apparent reactivity reached a maximum for the char generated at 6.2 bar and decreased with further increases in pressure. Among the kinetic parameters, the activation energies were not affected over the range of char generation pressures (3.4–21.7 bar), while the pre-exponential factors were within similar orders of magnitude. The order of reaction was determined by varying the CO2 partial pressure. The order of reaction decreased with increasing char generation pressure and closely followed the surface area at that conversion in most cases.",
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Intrinsic gasification kinetics of coal chars generated in a high-pressure, high-temperature flow reactor. / Krishnamoorthy, Vijayaragavan; Krishnamurthy, Nandakumar; Pisupati, Sarma V.

In: Chemical Engineering Journal, Vol. 375, 122028, 01.11.2019.

Research output: Contribution to journalArticle

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