By Marc Karell, P.E., CEM, Principal, Climate Change & Environmental Services, LLC
Virtually all states that have nonattainment areas for ozone have passed a rule called nitrogen oxide (NOx) Reasonably Achievable Control Technology (RACT). NOx is a precursor for ground-level ozone formation. With many regions in the country still not in attainment with the National Ambient Air Quality Standard for ozone approaching 4 decades, several states have or are considering toughening this rule to reduce NOx emissions. In New York, the NOx RACT rule, found in 6NYCRR Part 227-2, was amended in 2010. All significantly-sized combustion sources must meet these "reasonable" standards, defined as standards that are technologically achievable and not overly expensive.
The revised rule in New York (which will go into effect on July 1, 2014) contains new NOx emission limits for different fuels for different-sized boilers, any boiler with a maximum heat input of 25 mmBtu/hr or greater. Any boiler below that level must undergo a formal annual tune-up. The revised NOx RACT rule contains more stringent NOx emission limits, particularly for the combustion of coal and of No. 6 fuel oil. A New York State DEC official told me that the standards were based on successfully meeting these standards elsewhere. However, a number of boiler and burner vendors have told me that their equipment either simply cannot meet the new NOx emission limits or, at least, they would not guarantee their equipment meeting these limits. This is particularly telling as equipment vendors are usually optimistic that their units can meet emission standards to promote sales. If they are admitting that their equipment cannot, then it may be believable that the limits may be extraordinarily difficult to meet. Therefore, while likely unintentional, NOx RACT could be construed as being used to virtually eliminate the use of coal and No. 6 fuel oil altogether in the state. Could this be a trend in other areas or jurisdictions - developing environmental standards so stringent that they legislate out a particular operational practice, fuel or equipment?
What is a facility to do? First, one must recognize that this rule must be addressed promptly. Even a deadline date several years down the road gives little time to waste because of the time necessary to strategize, design, order, install and test new equipment. In New York, the time is now. If a facility operates boilers combusting coal and/or No. 6 oil, it needs to review any old stack tests to determine how the units have performed in the past. It is likely that emissions measured would not meet the future limits. Simply saying that you will "clean the tubes" or otherwise tune-up your units will probably not achieve compliance. And as you saw above, even installing more modern burners will likely not achieve compliance either. So what are your choices? De-rating boilers such that they would be exempt from emission limits could work - if this gives your facility the proper operating flexibility. Proof of de-rating by some type of physical fuel flow restriction, such as a plate or nozzle, may be necessary. Another possibility is fuel switching to a different "cleaner" fuel and burner upgrades to attain that emission standard. Fuel switching will also cause decreases in emissions of other pollutants and CO2, a greenhouse gas. Finally, remember that most NOx RACT rules allow the facility to submit an economic analysis that may determine that technology to meet the emission standard is not economically feasible and should be exempt.
CCES can help your facility in any state assess the NOx emissions of your boilers and strategize cost-effective options to lower them to comply with future regulations.
Reprinted with permission by CCES.
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