Which process is used to remove sulfur oxides from exhaust streams?

Which process is used to remove sulfur oxides from exhaust streams?

• A. Limestone scrubbing
• B. Catalytic cracking
• C. Carbon capture and storage
• D. Cyclone separation

Answer: (A)

Sulfur oxides are cleaned from exhausts by a wet scrubbing process that uses limestone. In a limestone scrubber, exhaust gas is brought into contact with a slurry of calcium carbonate (limestone). The calcium compounds react with the sulfur oxides (SO2, and SO3) to form solid sulfite or sulfate compounds, such as calcium sulfite or calcium sulfate (gypsum). These solids are removed from the system as a waste/byproduct, while the cleaned gas is released. This method is a standard approach for reducing SOx emissions from fossil-fuel combustion and is specifically designed to target sulfur oxides. Other options don’t fit the purpose: catalytic cracking is a refinery process for breaking larger hydrocarbons into lighter ones; carbon capture and storage focuses on CO2 capture rather than sulfur oxides; cyclone separation mainly removes particulates, not gaseous sulfur compounds.

Sulfur oxides are cleaned from exhausts by a wet scrubbing process that uses limestone. In a limestone scrubber, exhaust gas is brought into contact with a slurry of calcium carbonate (limestone). The calcium compounds react with the sulfur oxides (SO2, and SO3) to form solid sulfite or sulfate compounds, such as calcium sulfite or calcium sulfate (gypsum). These solids are removed from the system as a waste/byproduct, while the cleaned gas is released. This method is a standard approach for reducing SOx emissions from fossil-fuel combustion and is specifically designed to target sulfur oxides.

Other options don’t fit the purpose: catalytic cracking is a refinery process for breaking larger hydrocarbons into lighter ones; carbon capture and storage focuses on CO2 capture rather than sulfur oxides; cyclone separation mainly removes particulates, not gaseous sulfur compounds.