The report gives results of a full-size demonstration of the magnesia wet-scrubbing system for flue gas desulfurization (FGD) on a coal-fired utility boiler. The system was designed to desulfurize half the flue gas from a 190-MW rated capacity generating unit firing 3.5% sulfur coal. The FGD installation was equipped with a first-stage wet scrubber for particle emissions control, followed by the magnesia unit. The FGD system was able to remove 90% of the inlet SO2 over 2800 hours of operation logged at the generating station. Its particle control capability was also demonstrated by reducing particle emissions to less than 0.01 gr/scf with the unit operated in series with an electrostatic precipitator. A test program, using only the wet-scrubbing unit for particle emissions control, achieved a collection efficiency of 99.6%. Magnesia was regenerated and recycled successfully. The SO2 produced during regeneration was used to manufacture commercial grade sulfuric acid which was marketed. Correlations were developed to determine SO2 removal for varying boiler loads and fuel sulfur content, and to control regeneration of acceptable alkali. Several other studies of the process technology and process chemistry were undertaken as part of the work.

Prepared under contract no. 68-02-1870, program element no. EHB528. "March 1977." "EPA 600-7-77-018." Cover title. Includes bibliographical references.