The evolution and formation of tar species in a downdraft gasifier: numerical modelling and experimental validation

Salem, A. M., Zaini, I. N., Paul, M. C. and Yang, W. (2019) The evolution and formation of tar species in a downdraft gasifier: numerical modelling and experimental validation. Biomass and Bioenergy, 130, 105377. (doi: 10.1016/j.biombioe.2019.105377)

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Gasification is one of the most important methods for converting biomass to syngas currently used in energy production. However, tar content in syngas limits its direct use and thus requires additional removal techniques. The modelling of tar formation, conversion and destruction along a gasifier could give a wider understanding of the process and subsequently help in tar elimination and reduction. However, tar complexity, which contains hundreds of species, makes the modelling process hard and computationally intensive, because the chemistry of the formation and the combustion of many species have not yet been fully studied. In this work, a detailed kinetic model for the evolution and formation of tar from downdraft gasifiers, for the first-time, was built. The model incorporates four main tar species (benzene, naphthalene, toluene, and phenol) with a total of eighteen different kinetic reactions implemented in the code for every zone. Experimental work was carried out to initially validate the results of the kinetic code and found a good agreement. Further experiments were conducted at three different equivalence ratios (ERs) and at three different temperatures (800, 900, and 1100 °C). Sensitivity analysis was then carried out by the kinetic code to optimise the working parameters of a downdraft gasifier that led to a higher calorific value of syngas. The results reveal that a tar evolution model is more accurate for wood biomass materials and that using ER around 0.3, and moisture content levels lower than 10% lead to the production of higher value syngas with lower tar amounts.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Paul, Professor Manosh and Salem, Ahmed Morsy Mostafa
Authors: Salem, A. M., Zaini, I. N., Paul, M. C., and Yang, W.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
Journal Name:Biomass and Bioenergy
ISSN (Online):1873-2909
Published Online:25 September 2019
Copyright Holders:Copyright © 2019 Elsevier Ltd.
First Published:First published in Biomass and Bioenergy 130:105377
Publisher Policy:Reproduced under a Creative Commons license

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
301784Next Generation Advanced Gasification TechnologyManosh PaulRoyal Academy of Engineering (RAE)LTSRF1718\14\45ENG - Systems Power & Energy