Various industrial processes such as burning fossil fuels and refining gasoline produce sulfur dioxide as a byproduct. You can’t simply release sulfur dioxide into the atmosphere as these toxins are dangerous to humans, animals, plants, and the environment. As we’ve previously mentioned, when inhaled, sulfur dioxide can cause multiple ailments, especially among the very young, the elderly, and those with respiratory conditions. The EPA regulates sulfur dioxide to limit emissions. To remove sulfur dioxide from flue gas emissions, many plant managers implement a flue gas desulfurization (FGD) system.
The FGD process
You can mitigate harmful flue emissions using several methods, but the two most common processes include wet and dry lime scrubbing. To apply wet scrubbing, you mix lime with water and spray it into the flue gas scrubber. The solution reacts with the acids found in the flue and precipitates them to the bottom as wet calcium sulfate you can then properly dispose of. For dry scrubbing, you inject lime into the flue where it can absorb the acids and then you remove the exhaust cylinders at the bottom of the flue. Both methods are highly effective for removing harmful acidic gases; however, wet scrubbing is more efficient and more expensive than dry scrubbing. Often, you want to choose your approach based on how much sulfur dioxide you’re dealing with. Regardless of your approach, keep in mind corrosion is very common in FGD systems.
All the materials present in an FGD system are highly corrosive. Everything from the lime slurry to the acidic gases can cause corrosion as well as serious wear and tear on your tanks and piping systems. Uniform corrosion, which occurs when acids condensate, is often the result of the scrubbing solutions. In addition, the wet lime slurry is abrasive in nature which can degrade metals in the system, leaving them at greater risk for deterioration. Further, “FGD purge waters pose unique challenges because they are rich in pollutants such as heavy metals, mercury, and selenium, and they can be highly corrosive with high levels of dissolved solids and halide concentrations.” How can you better protect an important and necessary investment such as an FGD system?
Outside of careful FGD system design, one of the best ways to prevent corrosion is to install secondary containment rubber liners in your system. Rubber liners are a smart and cost-effective addition that provide a second layer of protection. There’s no avoiding such highly corrosive and abrasive materials because they’re inherent to the FGD process. Vulcanized rubber liners are specifically designed to seal your pipes and tanks, removing contact with harsh materials and reducing potential damage to the system overall. Thus, durable rubber liners can help uphold the FGD system’s integrity, protecting your investment and enhancing its longevity.