This post was written by Mark Mustian.
After some ten years in the making, last week the U.S. Environmental Protection Agency (USEPA) issued a final rule aimed at regulating emissions of hazardous air pollutants from industrial, commercial, and institutional boilers located at major source facilities. A major source facility emits or has the potential to emit 10 or more tons per year (tpy) of any single air toxic or 25 tpy or more of any combination of air toxics. USEPA also finalized a related rule to reduce emissions from industrial, commercial, and institutional boilers located at area source facilities. An area source facility has the potential to emit less than 10 tpy of any single air toxic or less than 25 tpy of any combination of air toxics.
The rules, known as the Boiler Maximum Achievable Control Technology or “Boiler MACT” rules, will affect a significant number of entities. USEPA estimates that there are about 13,800 boilers located at large sources of air pollutants, including refineries, chemical plants, and other industrial facilities. USEPA estimates that there are about 187,000 boilers located at small sources of air pollutants, including universities, hospitals, hotels and commercial buildings that may be covered by these standards.
For key requirements of the Boiler MACT rules and some implications, please click on “continue reading.”
Requirements for Boilers at Major Source Facilities
For boilers located at major source facilities, the following requirements are being implemented:
- For all new and existing natural gas- and refinery gas-fired units, the final rule establishes a work practice standard, instead of numeric emission limits. The operator will be required to perform an annual tune-up for each unit. Units combusting other gases can qualify for work practice standards by demonstrating that they burn “clean fuel,” with contaminant levels similar to natural gas.
- For all new and existing units with a heat input capacity less than 10 million British thermal units per hour (MMBtu/hr), the final rule establishes a work practice standard instead of numeric emission limits. The operator will be required to perform a tune-up for each unit once every 2 years.
- The final rule establishes a work practice standard instead of numeric emission limits for all new and existing “limited use” boilers. The operator will be required to perform a tune-up for each unit once every 2 years. These units are operated less than 10 percent of the year as emergency and backup boilers to supplement process power needs.
- The final rule establishes numeric emission limits for all other existing and new boilers and process heaters located at major sources (including those that burn coal and biomass). The final rule establishes emission limits for:
- Particulate Matter (PM)
- Hydrogen Chloride (HCl)
- Carbon Monoxide (CO)
- The final rule requires monitoring to assure compliance with emission limits. The largest major source boilers must continuously monitor their particle emissions. All units larger than 10 MMBtu/hr must monitor oxygen as a measure of good combustion.
- Existing major source facilities are required to conduct a one-time energy assessment to identify cost-effective energy conservation measures.
Requirements for Boilers at Area Source Facilities
Area source facilities will be required to meet the following:
- For new boilers, the final rule requires the following:
- Coal-fired boilers, with heat input equal or greater than 10 million Btu per hour, are required to meet emission limits for mercury, PM, and CO.
- Biomass and oil-fired boilers, with heat input equal or greater than 10 million Btu per hour, must meet emission limits for PM.
- Boilers with heat input less than 10 million Btu per hour must perform a boiler tune-up every two years.
- For existing boilers the final rule requires the following:
- Coal-fired boilers, with heat input equal or greater than 10 million Btu per hour, are required to meet emission limits for mercury and CO.
- Biomass boilers, oil-fired boilers, and small coal-fired boilers are not required to meet emission limits. They are required to meet a work practice standard or a management practice by performing a boiler tune-up every 2 years. By improving the combustion efficiency of the boiler, fuel usage can be reduced and losses from combustion imperfections can be minimized. Minimizing and optimizing fuel use will reduce emissions of mercury and all other air toxics.
- All area source facilities with large boilers are required to conduct an energy assessment to identify cost-effective energy conservation measures.
What This May Mean: More Gas and Less Coal
The obvious result from these new regulations will be to drive a move away from the use of coal as a fuel supply and to replace coal usage with natural gas. The majority of the existing coal fired boilers in the country will need to be retrofit with new, potentially very costly, air pollution control devices. Facilities which burn natural gas as a fuel can expect to see much lower costs for compliance with the new regulations. Facilities affected by this new rule will need to look closely at their costs for compliance in order to determine the most cost-effective solution for their situation.
Specific industries will also have compliance issues which are not adequately resolved in the current regulation. For example, manufacturers of coke for the iron and steel industry generate excess coke oven gas (COG) from their operations. These gasses are typically burned in a boiler to recover the heat value as opposed to flaring. However, COG may not qualify as a “clean fuel”. It may be necessary for coke plants which burn COG to install new controls on their boilers, even if they do not burn coal.
But Are They Really Final?
These new regulations have generated significant industry interest, and numerous and detailed comments were submitted during the draft period of the regulations. Most industry groups feel that USEPA has significantly underestimated the costs for compliance, and that EPA’s determination of the emission limitations is incorrect from both a technical and statistical basis. USEPA has recognized the continued debate, and has announced that they may reconsider certain portions of the rules and has requested additional comments and data submissions by the affected parties.
The final rules are due to be published in the federal register sometime this month.