Competitive or additive behavior for H 2 O and CO 2 gasification of coal char? Exploration via simplistic atomistic simulation

Yongbo Du, Chang'an Wang, Haihui Xin, Defu Che, Jonathan P. Mathews

Research output: Contribution to journalArticle

Abstract

Here, a large-scale char atomistic structure (41,438 carbon atoms) and simple simulation approaches explored char gasification behavior for H 2 O and CO 2 — comparing their mixture with one gas being passive (non-reactive) and the dual reactive mixture. Reactivity was captured through simplistic atomistic simulations via an automated sequence of gas diffusion, close-contact determination for gas (es) to reactive edge sites, then “reaction” via atom deletion. The higher reactivity of H 2 O was captured by a reaction probability function. For the reactive mixture (where both gases are reactive), the char consumption rate was 14% higher than with H 2 O alone, but lower (∼80%) than the sum of the individual gases (where only one gas is reactive), demonstrating competitive behavior. The H 2 O out competed the CO 2 molecules and contributed ∼83% to the char consumption — with the reaction rate being similar to that of H 2 O independently. The pore size development for individual gases also differed with H 2 O favoring development in the smaller pore sizes in comparison to CO 2 . With fewer gas molecules (using 10% to capture a lower pressure), the competitive behavior was muted and became much closer to additive behavior. These simple simulations are consistent with the emerging rationalization of contributing factors to char gasification.

Original languageEnglish (US)
Pages (from-to)226-237
Number of pages12
JournalCarbon
Volume141
DOIs
StatePublished - Jan 1 2019

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Coal
Carbon Monoxide
Gasification
Gases
Pore size
Atoms
Molecules
Diffusion in gases
Contacts (fluid mechanics)
Reaction rates
Carbon

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)

Cite this

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title = "Competitive or additive behavior for H 2 O and CO 2 gasification of coal char? Exploration via simplistic atomistic simulation",
abstract = "Here, a large-scale char atomistic structure (41,438 carbon atoms) and simple simulation approaches explored char gasification behavior for H 2 O and CO 2 — comparing their mixture with one gas being passive (non-reactive) and the dual reactive mixture. Reactivity was captured through simplistic atomistic simulations via an automated sequence of gas diffusion, close-contact determination for gas (es) to reactive edge sites, then “reaction” via atom deletion. The higher reactivity of H 2 O was captured by a reaction probability function. For the reactive mixture (where both gases are reactive), the char consumption rate was 14{\%} higher than with H 2 O alone, but lower (∼80{\%}) than the sum of the individual gases (where only one gas is reactive), demonstrating competitive behavior. The H 2 O out competed the CO 2 molecules and contributed ∼83{\%} to the char consumption — with the reaction rate being similar to that of H 2 O independently. The pore size development for individual gases also differed with H 2 O favoring development in the smaller pore sizes in comparison to CO 2 . With fewer gas molecules (using 10{\%} to capture a lower pressure), the competitive behavior was muted and became much closer to additive behavior. These simple simulations are consistent with the emerging rationalization of contributing factors to char gasification.",
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Competitive or additive behavior for H 2 O and CO 2 gasification of coal char? Exploration via simplistic atomistic simulation . / Du, Yongbo; Wang, Chang'an; Xin, Haihui; Che, Defu; Mathews, Jonathan P.

In: Carbon, Vol. 141, 01.01.2019, p. 226-237.

Research output: Contribution to journalArticle

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AU - Mathews, Jonathan P.

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