SO_x emissions from a fluidized-bed combustor with and without limestone addition

We consider the effects of operating variables on SO_x emissions in unstaged combustion with a stainless steel combustor that is 2 m high and has a 0.3 m × 0.3 m square cross section. Fluidizing air was supplied through a multihole distributor. The experiments were carried out for fluidizing velocities of 1-2 m/sec, bed temperatures of 830-880°C, 20-40% excess air, and bed particle sizes of 665 μm. SO_x emissions were reduced by over 70% with limestone. The bed temperature had the most significant effect on sulphur retention. Decreases in fluidizing velocity and increases in excess air result in increased SO_x reduction.