What is the most common method for removing sulfur dioxide from flue gas?

The most common method for removing sulfur dioxide from flue gas is through the use of lime, limestone, or sulfuric acid. This process typically involves a treatment known as flue gas desulfurization (FGD), where substances such as lime or limestone react with sulfur dioxide to form a solid product, primarily calcium sulfate. This reaction not only effectively reduces sulfur dioxide emissions but also leads to the generation of useful by-products that can be utilized in various industries, including cement and construction.

In FGD systems, the choice of chemical reactant is crucial as it determines the efficiency of sulfur dioxide removal. Lime and limestone are effective because they are readily available, cost-effective, and can be used in various forms. The overall process enhances environmental compliance by significantly lowering sulfur dioxide levels in emitted gases, which is important for reducing acid rain and improving air quality.

While other methods may attempt to address sulfur compounds in flue gas, the use of lime or limestone remains the most common due to its effectiveness, economic viability, and ability to create useful end products, which can then be utilized in industrial applications. Thus, this method not only addresses environmental concerns but also adds value to the waste material produced during the process.