Pakistan Receives its First Flue Gas Desulfuization (FGD) System

N/Aany%> has equipped AES Pak Gen (Pakistan) with a flue gas desulfurization (FGD) system. The unit reportedly is the first in a large-scale power plant in Pakistan. The FGD system includes the absorber, ancillary equipment, and reagent-handling and preparation systems.

The system removes up to 90% of the SO2 and 50% of the particulate emissions from the Unit 2 forced-circulation, high-sulfur-fuel, oil-fired boiler.

A single, open-spray tower absorber with an integral recycle tank treats the flue gas. Ground limestone is used as reagent and compressed air as forcing oxidant. Limestone slurry is fed into the absorber based on system pH. To minimize scaling and plugging, the recycle tank is sized to provide adequate retention time for limestone dissolution and gypsum crystallization.

Removal of waste slurry from the absorber is by a gravity-fed bleed stream to the absorber drain sump and then, by pumping, to the sludge ponds. Overflow from the gypsum sludge ponds passes to the gypsum sludge filtrate sump and is reused in the FGD system.

Particulate reduction occurs within the absorber, eliminating the need for an additional control device.

The FGD system is taken off line every evening because of low peak requirements. The cost-effective process design limits sparing capacity.

For more information contact Wheelabrator Air Pollution Control Inc. at 441 Smithfield Street, Pittsburg, PA, 15222-2292. Tel: 412-562-7300; Fax: 412-562-7617.