About 99 existing kraft pulp mills would be subject to EPA’s proposed amendments to its New Source Performance Standards (NSPS) for air emissions.  The proposal applies to emissions from discrete sources within a mill, specifically digester systems, brown stock washer systems, evaporator systems, condensate stripper systems, recovery furnaces, smelt dissolving tanks (SDTs), and lime kilns.

The NSPS for kraft pulp mills (40 CFR Part 60, Subpart BB) were promulgated in 1978 and last reviewed in 1986.  Primarily, the proposal would amend the NSPS emissions limit for particulate matter (PM). 

According to the EPA, the PM limit would be equivalent to the new source PM limits in the National Emissions Standards for Hazardous Air Pollutants (NESHAP) for chemical recovery combustion sources at kraft, soda, sulfite, and stand-alone semi-chemical pulp mills (40 CFR Part 63, Subpart MM), to which sources in the current proposal are already subject.  In other words, the proposed amendments will not result in additional emissions reductions.  Rather, says the EPA, the amendments would provide consistency for meeting the NSPS requirements and associated NESHAPS while achieving currently projected emissions reductions. 

New mills not anticipated
If made final, the amendments would apply to any mill for which construction, reconstruction, or modification is commenced after May 23, 2013.  The EPA does not anticipate that any new mills will be constructed.  However, based on historical data, the EPA estimates that 19 emissions units (8 recovery furnaces, 8 SDTs, and 3 lime kilns) at 10 kraft pulp mills will be constructed, modified, or reconstructed between 2013 and 2018 at a cost of $390,000 per year. 

PM limit
The proposed requirements, which would be included in a new subpart–40 CFR Part 60, Subpart BBa–are as follows:

• Reduce the NSPS PM limit for new and reconstructed recovery furnaces from 0.044 grains per dry standard cubic foot (gr/dscf) to the new source PM limit of 0.015 gr/dscf found in Subpart MM NESHAP.
• Reduce the opacity limit for recovery furnaces from 35 percent to 20 percent and reduce the monitoring allowance from 6 percent to 2 percent of the 6-minute opacity averages.
• Maintain the current NSPS total reduced sulfur (TRS) limits for recovery furnaces (5 parts per million of dry volume [ppmdv] for straight, 25 ppmdv for cross) and restrict the 1 percent monitoring allowance for TRS emissions to 30 ppmdv or less.  Previously, there was no TRS limit for these periods.
• Reduce the NSPS PM limit for new and reconstructed SDTs associated with new or reconstructed recovery furnaces from 0.2 lb/ton black liquor solids (BLS) to the new source PM limit of 0.12 lb/ton BLS in the Subpart MM NESHAP.
• Reduce the NSPS PM limit for modified lime kilns from 0.066 gr/dscf for gas-fired kilns and 0.13 gr/dscf for liquid-fired kilns to the existing source limit of 0.064 gr/dscf found in the Subpart MM NESHAP (for all fuels) and reduce the NSPS PM limit for new and reconstructed lime kilns from 0.066 gr/dscf for gas-fired kilns and 0.13 gr/dscf for liquid-fired kilns to the new source limit of 0.010 gr/dscf found in the Subpart MM NESHAP.

Also in Subpart BBa

In addition, the EPA is proposing that the following emissions limits for sources included in Subpart BBa for which construction, modification, or reconstruction is commenced on or after May 23, 2013,  be the same as those currently in Subpart BB:

• Maintain the current NSPS PM limit of  0.044 gr/dscf for modified recovery furnaces.
• Maintain the current NSPS TRS limit for SDTs at 0.033 lb/ton BLS.
• Maintain the current NSPS PM limit of 0.2 lb/ton BLS for modified and new and reconstructed SDTs not associated with a new or reconstructed recovery furnace.

Testing and monitoring

The proposed rule includes additional testing requirements and updated monitoring, recordkeeping, and reporting requirements for affected sources to ensure that control systems are properly maintained over time, ensure continuous compliance with standards, and improve data accessibility for the EPA, states, tribal governments, and communities.
Finally, the proposal would remove the exemption for periods of start-up and shutdown, resulting in a standard that applies at all times, says the EPA.

The proposal was published in the May 23, 2013, FR.