Abstract: An apparatus for the cleaning of flue gases containing ash and sulfur dioxide produced by burning sulfur-containing coal in the combustion chamber of a circulating fluidized-bed firing system includes a system for delivering a particulate SO2 sorbent into the combustion chamber. A feed system feeds a mixture of the ash, the SO2 sorbent/SO2 reaction product, and unreacted SO2 sorbent from the combustion chamber to a mixing unit. A liquid supply system supplies water or an aqueous sodium-containing solution to the mixing unit, whereby the unreacted SO2 sorbent is converted into a hydration product. A discharge system returns the ash, the reaction product, and the hydration product from the mixing unit into the combustion chamber, where the hydration product is reactivated into an SO2 sorbent at a combustion temperature of 700° to 950° C.

Abstract: An apparatus for the cleaning of flue gases containing ash and sulfur dioxide produced by burning sulfur-containing coal in the combustion chamber of a circulating fluidized-bed firing system includes a system for delivering a particulate SO2 sorbent into the combustion chamber. A feed system feeds a mixture of the ash, the SO2 sorbent/SO2 reaction product, and unreacted SO2 sorbent from the combustion chamber to a mixing unit. A liquid supply system supplies water or an aqueous sodium-containing solution to the mixing unit, whereby the unreacted SO2 sorbent is converted into a hydration product. A discharge system returns the ash, the reaction product, and the hydration product from the mixing unit into the combustion chamber, where the hydration product is reactivated into an SO2 sorbent at a combustion temperature of 700° to 950° C.

Abstract: A process for cleaning flue gases containing ash and sulfur dioxide produced by burning sulfur-containing coal in the combustion chamber of a circulating fluidized-bed firing system includes delivering a particulate SO2 sorbent into the combustion chamber. A mixture including portions of the ash, the reaction product produced in the reaction of the SO2 sorbent with the sulfur dioxide, and unreacted SO2 sorbent is fed from the combustion chamber to a mixing unit. In the mixing unit, water or an aqueous sodium-containing solution is mixed with this mixture and the unreacted SO2 sorbent is converted into a hydration product (for example Ca(OH)2) at a reaction temperature of 60° to 100° and at atmospheric pressure. The ash, the reaction product, and the hydration product is returned from the mixing unit into the combustion chamber, and the hydration product is reactivated to an SO2 sorbent at a combustion-chamber temperature of 700° to 950° C.

Abstract: A process for cleaning flue gases containing ash and sulfur dioxide produced by burning sulfur-containing coal in the combustion chamber of a circulating fluidized-bed firing system includes delivering a particulate SO2 sorbent into the combustion chamber. A mixture including portions of the ash, the reaction product produced in the reaction of the SO2 sorbent with the sulfur dioxide, and unreacted SO2 sorbent is fed from the combustion chamber to a mixing unit. In the mixing unit, water or an aqueous sodium-containing solution is mixed with this mixture and the unreacted SO2 sorbent is converted into a hydration product at a reaction temperature of 60° to 100° and at atmospheric pressure. The ash, the reaction product, and the hydration product is returned from the mixing unit into the combustion chamber, and the hydration product is reactivated to an SO2 sorbent at a combustion-chamber temperature of 700° to 950° C.

Abstract: A process for circulating solid particles within a fluidization chamber, in which is formed a circulating fluidized bed comprising a dense lower zone (A) with a high concentration of particles, above which is located a dilute zone (B) containing particles carried along by the rising stream of a gas towards the upper part of the chamber (1), the latter opening into a circuit (4) for discharging the gases and particles, incorporating a device (41) for recovering the particles carried along, which is connected to the chamber (1) by means of a circuit (45) for recycling the recovered particles. In the upper part (12) of the fluidization chamber, the circulation speed of the cases is reduced before their discharge, so as to produce above the dilute zone (B) an upper zone (C) with a higher concentration of particles, in which some (35) of the particles escape from the stream of gas and fall in a shower along the side wall of the chamber, at the same time forming a descending annular film (34).