Title:
A One-Dimensional Transient Fuel Conversion Model for Grate Combustion Optimisation
Author(s):
Martinez-Garcia, J, Nussbaumer, T.
Document(s):
Paper
Abstract:
A one dimensional transient model for simulating the conversion of solid biomass fuel in grate boilers is presented. The model considers drying, pyrolysis, and char oxidation, gas flow through the pore space of the bed, conductive, convective and radiative heat transfer, and reduction of the bed volume. It allows to study the influence of fuel properties (moisture, ash, composition, particle size, bed porosity, solid density) and operating parameters (excess air ratio, temperature). The applicability of the model is described by a 1.2 MW grate boiler operated at optimised conditions in a reference case. When the fuel humidity is increased, the original parameter settings result in an undesired combustion regime due to the increase of fuel bed volume and time for fuel drying. Consequently, unburnt carbon results in the grate ash. Model runs with adopted parameter settings reveal that ideal conditions on the grate can be recovered by pre-heating of the primary air, or by reducing the boiler capacity, or by utilisation of fuel with smaller particle size. Based on this example, the model shows to be a useful tool to predict the influence of parameters on the fuel conversion and is applicable for combustion design and development of control strategies.
Keywords:
fuel properties, modelling, grate combustion, modeling
Topic:
R&D on Biomass Conversion Technologies for Heating, Electricity and Chemicals
Subtopic:
Solid biofuel combustion for small and medium scale applications
Event:
21st European Biomass Conference and Exhibition
Session:
2DV.3.61
Pages:
1213 - 1219
ISBN:
978-88-89407-53-0
Paper DOI:
10.5071/21stEUBCE2013-2DV.3.61
Price:
FREE
