New Scrubber Design for Wet FGD Applications

摘要

European countries have made significant progress in reducing pollutant emissions,rnparticularly sulphur dioxide (SO2) emissions. This is clearly the result of the implementationrnof new environmental policies and regulations, the changes in the level and focus ofrneconomic activities, the selection of low-sulphur fuels and the application of Flue GasrnDesulphurisation (FGD) technology.rnWet scrubbers, especially the limestone/gypsum processes, are the most widely used FGDrntechnology for SO2 control. The configuration of wet limestone/gypsum scrubbers (with insiturnoxidation) can be generally classified into spray towers, packed towers, two-loop conceptrnor turbulent bed reactor. In the past years, ALSTOM has focussed on the improvement of thernturbulent bed reactor configuration and some results are presented in this paper.rnIn the turbulent bed reactor, the flue gas is forced to pass through a cross-flow absorptionrnslurry bed via holes in a sieve tray while limestone slurry is fed into the reactor and air, forrnoxidation and for driving the slurry circulation, is blown into the slurry.rnALSTOM's new wet scrubber – FLOWPAC – has resulted in an improved design with thernability to displace large masses of slurry using relatively modest amounts of pressurised air.rnIn addition to high liquid-to-gas ratio, the FLOWPAC system eliminates the need for recyclernpumps and integrates the oxidation process, thereby minimising operating difficulties as wellrnas power consumption. The new design enables a high flexibility in absorption performancernwith immediate controllability of the SO2 removal rate. FLOWPAC ensures wide fuelrnflexibility for power plant operators while achieving environmental compliance.