engleski

Application of thermodynamic equilibrium modelling to a pilot-scale updraft gasifier

The development of renewable energy resources recorded a significant growth due to climate changes caused by the combustion of fossil fuels. Conversion of biomass into the gas suitable for further exploitation is recognized as a valuable energy resource because of the wide distribution and availability of raw materials. Biomass gasification is the thermochemical process of partial combustion in the oxygen-free environment with a final product of hydrogen-enriched syngas. In the produced syngas, tar is also formed and, consequently, the syngas heating value is decreased. Lately, a huge research effort has been directed towards reducing tars and increasing syngas purity. The development of mathematical models for describing the physical and chemical behaviour of the gasification process as a complementary approach to experiments is mandatory. The simplest modelling approach recognized as an efficient tool for predicting the biomass gasification behaviour is based on the so-called Thermodynamic Equilibrium Model (TEM). The model is based upon the assumption that the reacting species are left for an infinite amount of time, which means that the results may vary considerably from a real-life scenario. TEM models are not computationally demanding, while the reasonable accuracy of predicting the gasification process at the quasi-stationary state could be achieved. In this work, two types of TEM models (stoichiometric and non-stoichiometric) were applied to a pilot-scale updraft biomass gasifier. Both models were validated against literature experimental data, and the obtained results provided detailed insights into the advantages and drawbacks of each model. Following validation, the models were used to analyse the influence of the operating conditions on gasification performace.

Biomass gasification, Thermodynamic equilibrium model, updraft fixed bed reactor

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