Modeling Biomass Gasification Using Thermodynamic Equilibrium Approach

  • Hua-Jiang Huang
  • Shri RamaswamyEmail author


In this paper, the thermodynamic equilibrium models for biomass gasification applicable to various gasifier types have been developed, with and without considering char. The equilibrium models were then modified closely matching the CH4 only or both CH4 and CO compositions from experimental data. It is shown that the modified model presented here based on thermodynamic equilibrium and taking into account local heat and mass considerations can be used to simulate the performance of a downdraft gasifier. The model can also be used to estimate the equilibrium composition of the syngas. Depending on the gasifier type and internal fluid flow, heat and mass transfer characteristics, with proper modification of the equilibrium model, a simple tool to simulate the operation and performance of varying types of biomass gasifier can be developed.


Biomass Gasification Chemical equilibrium Modeling Downdraft gasifier Syngas 



number of atom H in the biomass formula CH a O b N c S d based on 1 mol of carbon


coefficients of the heat capacity formula


change in coefficient A of a reaction, see formula 17


number of atom O in the biomass formula CH a O b N c S d


coefficients of the heat capacity formula


change in coefficient B of a reaction, similar to formula 17


number of atom N in the biomass formula CH a O b N c S d


coefficients of the heat capacity formula


heat capacity, J/mol·K


change in coefficient C of a reaction, similar to formula 17


number of atom S in the biomass formula CH a O b N c S d


coefficients of the heat capacity formula


change in coefficient D of a reaction, similar to formula 17


stoichiometric coefficient of H2O (liquid) in the overall gasification reaction 1


coefficients of the heat capacity formula


stoichiometric coefficient O2 in the overall gasification reaction 1


stoichiometric coefficient N2 in the overall gasification reaction 1


standard Gibbs free-energy change of a reaction at 298.15 K, J/kmol

\(\Delta G_{fi}^0 \)

Gibbs energy of formation of component i at 298.15 K, J/mol

\(\Delta H_{T_0 }^0 \)

standard heat of reaction at temperature of T 0 (=298.15 K), J/mol


represents the mole numbers of H2, CO, CH4, CO2, H2O(g) and C(s), i = 1,2,…6


equilibrium constant at 298.15 K


equilibrium constants of the three equilibrium reactions 5–7


the total pressure in the reaction system, Pa


ideal gas constant


reference temperature, T 0 = 298.15 K


reaction temperature, K



standard state for property values



The University of Minnesota Initiative for Renewable Energy and the Environment (IREE) is gratefully acknowledged for its financial support.


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Copyright information

© Humana Press 2008

Authors and Affiliations

  1. 1.Department of Bioproducts and Biosystems EngineeringUniversity of MinnesotaSt. PaulUSA

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