| Author | Das, Asit |
| Call Number | AIT Thesis no. ET-89-02 |
| Subject(s) | Fluidized-bed combustion
|
| Note | A thesis submitted in partial fulfillment of the requirements for the
degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | Biomass energy resource, in the developing countries, often
contributes 50-90% of national energy demands and could meet more diverse
energy needs through combustion in generating power and other heating
requirements. Circulating Fluidised Bed (CFB) is an attractive technique
of combustion which proved its special ability to burn a wide variety of
solid biomass fuels.
In the present work, a mathematical model for the steady state
combustion of char in a CFB has been developed taking into account bed
hydrodynamic conditions, chemical reaction rates, combustion mechanism
and conservation of mass. The model is an improvement over the much
simplified combustion model developed by BASU, SETT and GBORDZOE (1987).
The present model, apart from a few other improvements, includes a fairly
recent and an important aspect of solid backmixing i.e. solid flow down
the combustor wall in a film as reported by BOLTON and DAVIDSON (1988).
Variation of bed density along the height of the combustor, as a
consequence to above phenomenon, has also been considered.
The mode l has been used to predict oxygen and carbon concentrations
along the height of the combustor. Since the model allows to consider a
particle size distribution for the feed, it predicts fuel particle size
distribution at the exit of the combustor.
A CFB combustion system has been developed for which a successful
startup procedure has been reported. Results from combustion tests of
charcoal have been compared with model predictions. Experimental results
showed qualitative agreement with the theory.
Combustion test has been carried out with saw dust in order to make
preliminary observations about capability of the CFB combustor to burn a
fuel with characteristic high volatile content. The result shows somewhat
poor efficiency (87.8%) at a low excess air level of 11%. |
| Year | 1989 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Bhattacharya, Sribas C.; |
| Examination Committee(s) | Mora, Jean-Claude;Prida Wibulswas; |
| Scholarship Donor(s) | The Royal Danish Government (DANIDA); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1989 |