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.

more »

... lly 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. Index Terms-Flue gas cooler, discrete particle model, flow rate, lagrangian approach.