A Bubbling Fluidized Bed Combustion System for Forest Residues

Abstract

The main objective of the project was to develop or adapt a combustion technology that would permit a stable operation of a boiler fed with a combustible with a high level (50%) of humidity. The size of the unit was determined by the heating demand of a lacto-serum plant. Computer simulations and small scale laboratory experiments were used to design a fluidized bed, then fluid flow and heat transfer calculations were carried out to verifiy the heat balance (or energy balance) of an existing fixed boiler to be converted into à fluidized bed one. A grid involving 130 nozzles with 6 equally distributed holes (10 mm) was designed. The intake has a 23.37 mm I.D. It has been in operation for more than a year now and operation results are presented. It was found that the key aspect of the combustion process in such boilers is the homogeneity of the fluidized bed and the temperature control. We are now working on a way to broaden the range of type of wood and humidity levels.