Process and Apparatus For Treating Flue Gas From Sintering Plants

Process for treating flue gas from sintering plants, in which dry additive consisting at least of adsorbent and recirculated material and if appropriate additionally reagent, such as lime or lime hydrate, is added by the entrained-flow process to the flue gas from a sintering plant in a flue-gas duct, and the additive is then separated out of the flue gas by fabric filters and at least partially recirculated, wherein additive is introduced in the opposite direction to the direction of flow of the flue gas, specifically upstream and/or downstream of a gas conditioner, recirculated material, on the one hand, and fresh adsorbent and if appropriate reagent, on the other hand, being introduced at different locations, and fresh adsorbent and/or reagent being introduced before recirculated material.

Process according to claim 1, wherein the addictive is introduced into the flue gas with a relative velocity of at least 30 m/s.

Process according to claim 1, wherein the flue gas is cooled and/or humidified in a controlled way by injection or atomization of water into the flue gas stream independently of the addition of additive.

Process according to claim 3, wherein the water is introduced with a defined maximum drop size.

Process according to claim 3, wherein the maximum drop diameter is less than 200 μm.

Process according to claim 1, wherein additive, at least in a defined cross section of the flue gas duct, is introduced at a plurality of locations distributed over the cross section.

Process according to claim 1, wherein additive is introduced at a plurality of locations along the direction of flow of the flue gas.

Process according to claim 1, wherein additive is introduced via at least one lance.

Process according to claim 1, wherein the flue gas is cooled and/or humidified in a controlled manner by injection or atomization of suspension or solution, such as a suspension of lime hydrate in water, into the flue gas stream in the gas conditioner.

Process according to claim 1, wherein adsorbent is introduced as a function of the level of the condensable organic compounds and/or the heavy metals.

Process according to claim 1, wherein reagent is introduced and/or the flue gas is cooled and/or humidified as a function of the level of the acidic constituents in the flue gas.

Apparatus according to claim 12, wherein in at least one defined cross section of the flue gas duct, openings of a feed device are arranged at a plurality of locations distributed over the cross section.

Apparatus according to claim 12, wherein the feed device has at least one lance for introducing the additive.

Apparatus according to claim 12, wherein a feed supplying water, suspension or solution with a defined maximum drop size is provided in the gas conditioner.

Apparatus according to claim 15, wherein a control unit is provided, by which the quantities of water, suspension or solution, the quantity of recirculated material and the quantity of fresh additive can be controlled independently of one another, specifically as a function of the condition of the untreated and/or purified flue gas.