Patent ID: 7776298

Claim:
A method for the separation of the pollutants, dust, HF, HCl, SO 2 , SO 3 , heavy metals, heavy-metal compounds, polyhalogenated hydrocarbons and polycyclic hydrocarbons from combustion flue gases containing such pollutants by a process comprising treating the pollutant-containing combustion flue gases with a sorbent in a circulating fluidized bed comprising a reactor, a separator and a return line, wherein the pollutant-laden sorbent is separated off from a gas/solid suspension in the separator and in part recycled to the reactor via the return line and in part discharged, wherein the recycled sorbent is introduced upstream of the reactor, via the return line, separately from the fresh sorbent, wherein the sorbent is a mixture of Ca(OH) 2 , at least one naturally occurring zeolite, and a carbon-containing substance, wherein the sorbent has a mean particle size d 50 of 2 to 50 μm, the process is carried out at 120 to 180° C. in the presence of steam wherein water is added in a lower part of the reactor in the form of drops having a diameter of <40 μm, the reactor is operated at a gas velocity of 2 to 10 m/s, and a mean residence time of the solids particles in a single pass of 1 to 10 seconds, wherein the gas/solid suspension present in the reactor has a mean suspension density of 1 to 10 kg of solid/Nm 3 flue gas, wherein the separation of the loaded sorbent in the separator is carried out by filtration, wherein the process is operated at a solids circulation rate of 10-100, and the loaded sorbent located in the return line and a fresh sorbent are each fluidized and transported by adding a part-stream of the cleaned combustion flue gases or adding pre-warmed air, wherein the operating conditions in the circulating fluidized bed are kept constant in the event of a change in the amount of combustion flue gases to be cleaned (partial load operation) by adding a part-stream of the cleaned combustion flue gases.