Patent ID: 8226754

Claim:
A flue gas desulfurization (FGD) system for retrofitting on an existing coal-fired boiler, for scrubbing the raw flue gas generated by said boiler; comprising: (a) an inlet means connected for receiving from said boiler the raw flue gas to be scrubbed; (b) an outlet means connected to receive scrubbed flue gas and direct it for discharge; (c) an absorber connected between said inlet and outlet means for receiving the flue gas from said inlet means and removing SO 2 for subsequent discharge; (d) said absorber including a horizontal cocurrent scrubber section for contacting the flue gas with scrubbing reagents contained in a droplet dispersed slurry or solution; (e) means for cocurrently flowing said flue gas and droplet dispersed reagent slurry or liquid through said absorber while generating a pressure rise across said absorber; (f) said absorber including a spray zone for introducing said droplet dispersed slurry of scrubbing reagents; (g) said spray zone including cocurrent spray nozzles at said spray zone and one or more spray headers for delivering said slurry to said nozzles, for injecting said slurry at a higher velocity of flow than the bulk flow velocity at said zone of said flue gas, thereby contributing to the said pressure rise across said absorber; and (h) wherein said absorber includes a quench header upstream of the spray zone to wash the spray header in proximity to the quench header, to avoid solids buildup at wet-dry interfaces located on the said spray header and the inlet means.