—In many industrial processes hot gas is cooled
down before it has been sent to atmosphere. The flue gas is a gas
mixture that mainly consists of oxygen, carbon dioxide, water
vapor and nitrogen. Additional it may contain sulphur dioxide,
nitrogen dio oxide and other marginal species. It usually also
contains dust and ashes. While the oxygen content is very much
lowered compared to that of ambient air, the content of carbon
dioxide can reach a volume fraction of up to twenty five percent.
Especially at the modern waste incineration plants the content
of water vapor can go up to a few percent.
In this work computational fluid dynamic model is formed
for flue gas cooler that are attached in series for 20 kW Oxy
fired Bubbling fluidized bed Combustor Using Coal and
Biomass. The model is based on the Lagraingian approach and
Discrete Particle Model. The model is solved using commercial
Software Ansys Fluent. The geometrical domain is formed in
Solid Works. The simulations were performed in Ansys Fluent
commercial software. The maximum air flow rate used for this
simulation is 80 kg per hour. The flue gas enters on the side of
gas cooler and few particles are entrained in gas cooler. The flue
gas is the sucked by ID fan. The flue gas is cooled with the help
of 0.5 HP water circulation pump. The pump circulates the
water through 0.5 inch pipe line. In order to cool the flue gas
down cold water a flow rate of 10-12 litre per minute and
temperature of 293 K is supplied. The velocity, temperature and
pressure contours are plotted. The results are also calculated
for different types of fuels. The various types of biomass and
coal are used in fluidized bed. This leads to variation of ash
particles size in flue gas. The particle size in fuel causes the
variation in size of ash in flue gas which in turn affects the
performance of flue gas cooler. The effect of variation in size of
particles on exit flue gas temperature is also investigated.
—Flue gas cooler, discrete particle model, flow
rate, lagrangian approach.
Ravi Inder Singh is with Birla Institute of Technology and Science-Pilani,
Pilani Campus Jhunjhunu, Rajasthan, 333031, India, 00911596515096
Cite: Ravi Inder Singh, "CFD Modeling of Flue Gas Cooler of Oxy Fired Bubbling Fluidized Bed Combustor Using Coal and Biomass," International Journal of Environmental Science and Development vol. 8, no. 4, pp. 236-240, 2017.