April 01, 2002

by Jim Coyle

Owners/ operators of boilers and internal combustion engines have many questions regarding their responsibilities under Part 227-2, Reasonably Available Control Technology (RACT) for Oxides of Nitrogen (NOx). Specifically, the issues of concern are:

• registration/permit options;
• operating procedures; and
• NOx control requirements.

This article will answer many of these questions. Specific questions may be addressed through the SBEAP’s technical hotline (800) 780-7227.

Do the NOx RACT requirements apply to the same size combustion installations throughout New York state?

Do these emission levels equate to certain size boilers, engines and types of fuel?

Are certain size boilers exempt from both NOx RACT and any permitting requirements?

What are my compliance options if the furnaces at my facility exceed the applicability levels or if the PTE at my facility would classify it as a Major source?

How do I limit my NOx emissions below the applicability threshold?

When should I request a cap from DEC?

Will capping my emissions generate any new requirements?

What if I cannot cap my NOx emissions below the applicability levels?

Do the NOx RACT requirements apply to the same size combustion installations throughout New York state?

No. There are two different applicability levels in the state. In the severe ozone non-attainment area (New York City and the counties of Nassau, Suffolk, Westchester, Rockland, and Lower Orange), the requirements apply to facilities with the potential to emit (PTE) 25 tons/yr or more of NOx. For the rest of the state, the threshold is a PTE of 100 tons/yr or more of NOx.

Please keep in mind that equaling or exceeding these emission levels will classify a facility as Major and will affect the type of permit you must obtain from DEC.

Do these emission levels equate to certain size boilers, engines and types of fuel?

Yes. The following table estimates the boiler/engine capacity (by type of fuel) associated with a PTE for NOx emissions that would trigger the NOx RACT requirements. Facilities whose total boiler or engine heat input capacity equals or exceeds these values must comply with the NOx RACT requirements.

Total Heat Inputs for boilers/engines*

PTE of 25 tons/yr   PTE 100 tons/yr
 (Downstate)     (Upstate)

 Boilers

residual oil  11.4 mmBtu/hr    45.6 mmBtu/hr
distillate oil  40.9 mmBtu/hr    163.9 mmBtu/hr
natural gas  40.9 mmBtu/hr    163.9 mmBtu/hr

Engines

    PTE of 25 tons/yr  PTE 100 tons/yr (Downstate)   (Upstate)

diesel fuel/natural gas   1.68 mmBtu/hr   6.75 mmBtu/hr
  
* “Total” means the sum of all boilers/engines at the facility. These limits are facility-wide.

Keep in mind that these values are associated with your boilers operating around-the-clock and at maximum capacity, which is the definition of PTE.

Are certain size boilers exempt from both NOx RACT and any permitting requirements?

Yes. Downstate, furnaces burning oil or natural gas with a maximum rated heat input capacity less than 10 million Btu/hr are exempt from needing any permit or registration. This value is 20 million Btu/hr or less for furnaces located upstate burning similar fuels. These exempt sources are also below the applicability level for NOx RACT.

If your furnace’s maximum rated heat input is not stated in millions of Btu’s per hour, use the following table to convert it to mmBtu/hr.

Common Conversions to mmBtu/hr

lbs steam/hr x .0014 = ____ mmBtu/hr
boiler horsepower x .0334 = ____ mmBtu/hr
mechanical horsepower x .0025 = ____ mmBtu/hr

With respect to internal combustion engines, the following are exempt:

• natural gas/diesel-fired engines located in the severe non-attainment area (downstate) with a maximum mechanical power rating of less than 225 brake horsepower;
  
  
• natural gas/diesel-fired engines located outside the severe non-attainment area (upstate) with a maximum mechanical power rating of less than 400 brake horsepower;
  
  
• gasoline-powered engines with a maximum mechanical power rating of less than 50 brake horsepower.
  

Any furnace that has the capability to burn either coal or wood and has a maximum heat input of less than 1 mmBtu/hr is exempt from any permit requirements, statewide.

What are my compliance options if the furnaces at my facility exceed the applicability levels or if the PTE at my facility would classify it as a Major source?

There are several compliance options available

• limit your potential to emit to below the NOx RACT applicability levels;
• develop a NOx RACT compliance plan; and/or
• apply for the appropriate permit/registration.

How do I limit my NOx emissions below the applicability threshold?

There are two ways to limit, or “cap,” your emissions:

• Part 201, Permits and Registrations, includes a provision that allows a facility to cap by rule through the Registration process if it can limit its emissions to less than 50% of the applicability thresholds (12.5 tons/yr downstate and 50 tons/yr upstate).
  
  
• Part 201 also includes a provision which allows a facility to limit its emissions by obtaining a State Facility Permit, if its emissions are over the 50% level but less than the applicability level. DEC has developed a General Permit that identifies the applicability requirements that can be utilized for this source category.  See "General Permits for Certain Combustion & Heating Units" article on page 8 of the Spring 1997 issue of the CleanAirNews.

When should I request a cap from DEC?

Part 227-2 required sources to either cap their NOx emissions below the major source threshold or implement the RACT requirements by June 1, 1995. In addition, Part 201 requires major boilers/stationary combustion sources to apply for a Title V permit by June 1997. A Title V Permit is a new type of air permit that all major facilities must obtain, even if they are currently permitted with DEC. DEC has also developed a General Permit for this category of sources (excluding coal/wood-fired units) that identifies the applicable requirements.  See "General Permits for Certain Combustion & Heating Units" article on page 8 of the Spring 1997 issue of the CleanAirNews.

Will capping my emissions generate any new requirements?

Yes. You will be required to maintain records to demonstrate that your fuel usage has remained below the limits specified on your permit or the limits in the capping by rule provision in Part 201, whichever applies. In addition, if you obtain a State Facility Permit, you will be required to certify on a annual basis that you have complied with the limits specified on your permit.

What if I cannot cap my NOx emissions below the applicability levels?

You should immediately develop a NOx RACT compliance plan. This plan should contain the necessary steps (purchase of equipment, installation of equipment, source testing, submittal of permit application) and projected completion dates required to bring the facility into compliance. This plan should be submitted to the appropriate DEC Regional office as soon as possible.

For small boilers (those whose capacity is as less than 50 mmBtu/hr), Part 227-2 requires an annual tune-up. There is a guidance document available from either the SBAP or DEC that includes all of the necessary components of an acceptable tune-up.

Larger boilers (> 50 mm Btu/hr) must install approved low-NOx burners (residual oil units must also utilize 10% flue gas recirculation) and/or meet fuel-specific emission limits, depending on boiler size.

Internal combustion engines must meet either a lean-burn or rich-burn NOx emission limit. The most cost-effective way to meet the emission limit is by retarding the timing on the engine. Any source subject to an emission limit must perform a stack test to demonstrate compliance.

The SBAP can assist you in calculating your current emission levels and determining the applicable requirements. In addition, we can assist in the development of a compliance plan for your facility and help you complete the appropriate permit or registration application.