Fluidised Bed Combustion of a Liquid Fuel: A Modelling Interpretation for Micro-Explosions

The present paper deals with the combustion of liquid fuels in bubbling fluidized bed. The focus is on micro-explosions that were observed in the intermediate temperature range 873-1023 K at a frequency in the range 2.4-3.8 Hz. A simplified model for the combustion of a rising fuel-bubble was purposely developed. It applies to a single non-premixed bubble that can undergo coalescence with other bed bubbles. A mechanistic approach is also adopted to relate the frequency of micro explosions to the frequency by which relatively well-premixed bubbles approach the bed surface. Even with large simplifications, the model is able to explain the temperature dependence of the micro-explosive behaviour as well as to provide a reasonable estimate for the micro-explosion frequency. The number of coalescences experienced by the endogenous bubble during its residence time is less than one with reference to the experimental conditions reported in the paper. The accordance between the experimental frequency of micro-explosions obtained when burning a commercial bio-diesel and the frequency of coalescence-free bubbles reaching the bed surface is rather good.

MICCIO Francesco;  FERRANTE Lorenzo; 

2007-02-12

ELSEVIER SCIENCE INC

JRC33310

https://publications.jrc.ec.europa.eu/repository/handle/JRC33310,   

10.1016/j.proci.2006.07.129,