Final answer:
Reducing sulfur oxides in flue gas is effectively done by scrubbing it with lime or limestone, which transforms sulfur compounds into less harmful substances.
Step-by-step explanation:
One proven method of reducing the sulfur oxides in flue gas is to: scrub the flue gas with lime or limestone. The process works by first blowing calcium carbonate into the combustion chamber, which decomposes to calcium oxide (lime) and carbon dioxide. The lime then reacts with the sulfur dioxide forming calcium sulfite. A suspension of lime is further injected to form a slurry, which removes the calcium sulfite and any remaining unreacted sulfur dioxide. This scrubbing method effectively reduces SO2 emissions and its conversion to acid rain, which has detrimental environmental effects.