Gaseous emissions from char particle combustion in a fluidized bed. (Senior Division).
There is a global need for the energy generated by coal combustion.
Coal combustion accounts for 52 percent of the total electricity
generated in the U.S. The great demand for coal stems from its
efficiency at such a low cost. Though economical, one problem with the
combustion of coal is that it emits gases that are harmful to the
environment and ecosystem. Among these are [N.sub.2]0 and N[O.sub.x],
which are produced during coal combustion. The goal is to find a way to
still bum coal for energy but reduce harmful emissions at the same time.
A relatively new way to combust coal is in a fluidized bed. While this
method has many beneficial effects, there are also some problems that
arise with this technology. This experiment focuses on the combustion of
char, rather than coal, in a fluidized bed. A char particle is a coal
particle that has been cleansed of its volatile organic compounds (VOCs)
through a process called coking. Char is used because it gives better
laboratory results than raw coal and is cleaner and safer to use. The
optimal conditions for maximum efficiency and minimal emissions have
been determined from the experimental data by altering the bed
temperature, the coal type, and the oxygen concentration. It was
discovered that the fluidized bed in the laboratory should operate
arguably at 600[degrees] C with an oxygen concentration of 10%. Since no
coal type was better than the other, no conclusions were made on that
investigation except that a high quality coal would be more favorable.
The results of this research provide a basis for which a company could
set up large scale fluidized bed combustion power plants that are in
compliance with the government standards for gaseous emissions.
Andrew M Coughlin and Virginia B Eakin Laramie High School, Laramie