Title: Reactor residence time analysis with CFD

Authors: Federico Ghirelli, Sven Hermansson, Henrik Thunman, Bo Leckner

Addresses: Department of Energy and Environment, Chalmers University of Technology, Gothenburg, Sweden. ' Department of Energy and Environment, Chalmers University of Technology, Gothenburg, Sweden. ' Department of Energy and Environment, Chalmers University of Technology, Gothenburg, Sweden. ' Department of Energy and Environment, Chalmers University of Technology, Gothenburg, Sweden

Abstract: The residence time of the fluid in a reactor can be analysed with at least three different computational methods: (a) Eulerian simulation of the residence time measurements; (b) solution of the Eulerian transport equation for residence time; (c) Lagrangian particle tracking. Methods (a) and (c) are compared with analytical and experimental data from a pilot lagoon for validation, and the superiority of the Eulerian approach is demonstrated. Method (b), which has been validated in earlier studies, is applied to study the flow in the secondary combustion chamber of a biomass grate furnace. An inefficiently exploited zone of the furnace is identified, and a change in operating conditions, aimed at improving the reactor utilisation, is discussed.

Keywords: fluid age; biomass combustion; pulse experiment; secondary air injection; furnace modelling; plug flow; reactor quality; flow analysis; CFD solution analysis; computational fluid dynamics; residence time analysis.

DOI: 10.1504/PCFD.2006.010033

Progress in Computational Fluid Dynamics, An International Journal, 2006 Vol.6 No.4/5, pp.241 - 247

Published online: 09 Jun 2006 *

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