An analysis of scaling on the inside wall of the Circulating Fluidised Beds Flue Gas Desulphurization (CFB-FGD) absorber and its mechanism was carried out. It was found that deposition and agglomeration mainly occurred in a circular high humidity area which was 4 to 5 meters above from the nozzles. Such factors affecting the deposition were studied

including system running conditions

tower makeup

nozzle size

in-tower flow and temperature profiles. The composition of the deposited materials was analysed. It was found that both the composition and the forming mechanism of scaling were far different from the wet FGD

and that scaling was caused mainly by wet ash which was easy to adhere to the wall

and secondly by CaCO3 which reflected the important role of CO2 in the scaling process. Finally

approaches to prevent scaling were proposed.For example，a specially designed multi-piped venturi scrubber was installed in order to increase the vertical velocity of the particles.