Industrial Boilers

Retrofitting Options for Boiler MACT Compliance

Industrial boilers are in a unique regulatory situation where they have an extremely short time to comply with the recently published Industrial Boiler MACT Standard. Due to the high potential capital costs and downtime required for full system replacement, wet electrostatic precipitators (WESPs) are a good solution for retrofitting or adding as a polishing step to existing air pollution control systems.

The EPA’s new strict emission limits for industrial boilers will require extensive retrofitting of existing systems and costs will vary significantly based on fuel type, boiler size, existing air pollution control conditions, and the additional control efficiencies required for continued compliance.

The rules increase regulatory focus on their acid gas emissions and fine particulate PM2.5. To meet compliance, existing air pollution control systems can be retrofitted with polishing systems to target pollutants such as sulfur oxides, hydrogen chloride, hydrogen fluoride, and mercury.

Industrial Boiler

AirPol’s installations are robust and have demonstrated long-term compliance with Federal Maximum Achievable Control Technologies (MACT) and Best Available Control Technologies (BACT) Standards.

Wet acid control systems use an alkali compound to increase the pH of the recycle liquid. Acid gas removal rates are based on factors like type, quantity, and reactivity of sorbent, and retention time.

WESPs have a unique design benefit of being able to grab the very fine particulates from the airstream, which makes it an ideal polishing step in an air pollution control system to meet the Industrial Boiler MACT Standards. WESPs use charged rods to create a field that pulls particulate from dirty flue gases and to water that is continuously flushed through the system. The energy demand and pressure drops across WESPs are relatively low, which makes retrofits and add-on final control installations cost-effective