Modelling super-equilibrium in biomass gasification with the constrained Gibbs energy method

Petteri Kangas (Corresponding Author), Ilkka Hannula, Pertti Koukkari, M Hupa

Research output: Contribution to journalArticleScientificpeer-review

19 Citations (Scopus)

Abstract

The biomass gasification process is modelled by utilising constrained thermodynamic equilibrium. The formation of char, tar, ammonia and light hydrocarbons and related syngas composition were described by extending the conventional chemical system with additional immaterial constraints and by defining process-dependent values for these constraints. Six different model structures were evaluated from global thermodynamic equilibrium to fully constrained local equilibrium. When models were validated against gasification setups, it was not necessary to fully constrain the system, as sufficient results were obtained by implementing constraints for char, tar, ammonia, CH4 formation as well as for the amount of carbon in light hydrocarbons. The method was shown to be versatile when it was validated against other gasification setups: by altering the models defining the constraints a new gasification conditions could be simulated. A clear benefit of the proposed method is that the gasification process can be resolved as a restricted partial equilibrium with a single calculation step. Another benefit is that chemical reactions, gasification enthalpy and the states of the system are estimated concurrently.
Original languageEnglish
Pages (from-to)86-94
Number of pages9
JournalFuel
Volume129
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Fingerprint

Gibbs free energy
Gasification
Biomass
Tars
Tar
Hydrocarbons
Ammonia
Thermodynamics
Model structures
Chemical reactions
Enthalpy
Carbon
Chemical analysis

Keywords

  • Biofuels
  • computational methods
  • constrained Gibbs energy
  • thermodynamics

Cite this

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title = "Modelling super-equilibrium in biomass gasification with the constrained Gibbs energy method",
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Modelling super-equilibrium in biomass gasification with the constrained Gibbs energy method. / Kangas, Petteri (Corresponding Author); Hannula, Ilkka; Koukkari, Pertti; Hupa, M.

In: Fuel, Vol. 129, 2014, p. 86-94.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Modelling super-equilibrium in biomass gasification with the constrained Gibbs energy method

AU - Kangas, Petteri

AU - Hannula, Ilkka

AU - Koukkari, Pertti

AU - Hupa, M

PY - 2014

Y1 - 2014

N2 - The biomass gasification process is modelled by utilising constrained thermodynamic equilibrium. The formation of char, tar, ammonia and light hydrocarbons and related syngas composition were described by extending the conventional chemical system with additional immaterial constraints and by defining process-dependent values for these constraints. Six different model structures were evaluated from global thermodynamic equilibrium to fully constrained local equilibrium. When models were validated against gasification setups, it was not necessary to fully constrain the system, as sufficient results were obtained by implementing constraints for char, tar, ammonia, CH4 formation as well as for the amount of carbon in light hydrocarbons. The method was shown to be versatile when it was validated against other gasification setups: by altering the models defining the constraints a new gasification conditions could be simulated. A clear benefit of the proposed method is that the gasification process can be resolved as a restricted partial equilibrium with a single calculation step. Another benefit is that chemical reactions, gasification enthalpy and the states of the system are estimated concurrently.

AB - The biomass gasification process is modelled by utilising constrained thermodynamic equilibrium. The formation of char, tar, ammonia and light hydrocarbons and related syngas composition were described by extending the conventional chemical system with additional immaterial constraints and by defining process-dependent values for these constraints. Six different model structures were evaluated from global thermodynamic equilibrium to fully constrained local equilibrium. When models were validated against gasification setups, it was not necessary to fully constrain the system, as sufficient results were obtained by implementing constraints for char, tar, ammonia, CH4 formation as well as for the amount of carbon in light hydrocarbons. The method was shown to be versatile when it was validated against other gasification setups: by altering the models defining the constraints a new gasification conditions could be simulated. A clear benefit of the proposed method is that the gasification process can be resolved as a restricted partial equilibrium with a single calculation step. Another benefit is that chemical reactions, gasification enthalpy and the states of the system are estimated concurrently.

KW - Biofuels

KW - computational methods

KW - constrained Gibbs energy

KW - thermodynamics

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DO - 10.1016/j.fuel.2014.03.034

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SN - 0016-2361

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