The EPA on Wednesday, May 27, proposed a supplemental action to the proposed amendments to the new source performance standards for coal preparation and processing plants published on April 28, 2008. The 2008 proposal, among other things, proposed to revise the particulate matter and opacity standards for thermal dryers, pneumatic coal cleaning equipment, and coal handling equipment located at coal preparation and processing plants. This supplemental action proposes to revise the particulate matter emissions and opacity limits included in the original proposal for thermal dryers, pneumatic coal-cleaning equipment, and coal handling equipment. It also proposes to expand the applicability of the thermal dryer standards so that the proposed standards for thermal dryers would apply to both direct contact and indirect contact thermal dryers drying all coal ranks and pneumatic coal-cleaning equipment cleaning all coal ranks.

In addition, the EPA proposes to establish an SO₂ emission limit and a combined NO_X and CO emissions limit for thermal dryers. The agency is proposing to amend the definition of coal for purposes of subpart Y to include petroleum coke and coal refuse. Finally, it proposes to establish work practice standards to control coal dust emissions from open storage piles and roadways associated with coal preparation and processing plants.

Comments must be received on or before July 13, 2009.

Background

On April 28, 2008 (73 FR 22901), in the wake of a massive and environmental destructive spill of coke and coal refuse, the EPA proposed amendments to the New Source Performance Standards (NSPS) for coal preparation and processing plants (40 CFR part 60, subpart Y). The Federal Register action for that original proposal included additional background information on the coal preparation NSPS. That information is not repeated in this action. The EPA said it received numerous comments in response to the April 2008 proposal. After reviewing those comments and considering additional data, the agency decided to publish this supplemental proposal which contains proposed emission limits and monitoring requirements that differ from those in the original action and proposes to apply those requirements to additional affected facilities.

Summary of proposed amendments

The EPA is proposing to establish emissions standards for both direct contact and indirect thermal dryers, and pneumatic coal-cleaning equipment that process all coal ranks. The agency is also proposing to establish work practice standards to control coal dust emissions from open storage piles and roadways associated with coal preparation and processing plants. In addition, the agency is proposing to establish an SO₂ emission limit and a combined NO_X and CO emissions limit for thermal dryers. Finally, the EPA is proposing particulate matter (PM) emission limits, opacity limits and monitoring requirements that differ from those included in the April 2008 proposal. For all standards proposed in the April 2008 proposed rule, this supplemental proposal will not change the applicability date for determining whether a source constitutes a "new source" subject to the final version of such standards. All standards originally included in the April 2008 proposed rule, regardless of whether the level of the standard is modified in this supplemental proposal or in an eventual final rule, apply to sources constructed, modified, or reconstructed after April 28, 2008.

Standards, such as the SO₂ and combined NO_X and CO standards, proposed for the first time in this supplemental proposal, apply to all sources constructed, modified, or reconstructed after May 27, 2009.

Affected facilities

The existing NSPS for coal preparation and processing plants in 40 CFR part 60, subpart Y establishes emission limits for the following affected facilities located at coal preparation and processing plants which process more than 181 megagrams (Mg) (200 tons) of coal per day:

• Thermal dryers
• Pneumatic coal-cleaning equipment (air tables)
• Coal processing and conveying equipment (including breakers and crushers)
• Coal storage systems
• Transfer and loading systems.

The terms "thermal dryer" and "pneumatic coal-cleaning equipment" are defined to include only facilities that process bituminous coal and "coal storage system" is defined to exclude open storage piles.

The EPA noted that several commenters suggested that standards should also be developed for indirect thermal dryers, thermal dryers drying all coal ranks, open storage piles, and coal dust associated with roadways associated with coal preparation and processing plants. Commenters said the EPA's original rationale for limiting the applicability for thermal dryers was a lack of emissions data and thermal dryers, and pneumatic coal-cleaning equipment processing non-bituminous coals did not exist and that these reasons are no longer valid. Commenters said indirect thermal dryers and direct contact thermal dryers "upgrading" subbituminous and lignite will become more common in the future. Even though power plant emissions might be decreased, if emissions standards are not established on the pre-combustion process, they argued, there is no environmental benefit and potential net degradation to air quality from coal "upgrading."

For open storage piles and roadways, commenters pointed out that both are significant sources of PM emissions for which control technology is available. One commenter pointed out that enclosures, wind fences and other barriers, and wet or chemical suppression are available control technologies. Potential controls for coal road dust include tire or truck wash systems, sweeper trucks, and wet suppression.

Based on its review of public comments and subsequent analysis, the EPA is proposing to amend the definition of thermal dryer for units constructed after May 27, 2009 to include both direct and indirect dryers drying all coal ranks. The agency is also proposing to amend the definition of pneumatic coal-cleaning equipment for units constructed after May 27, 2009 to include pneumatic coal-cleaning equipment cleaning all coal ranks. In addition, the agency is proposing to establish work practice standards that apply to open storage piles and roads associated with a coal preparation plant constructed after May 27, 2009.

PM and opacity limits for thermal dryers

In the April 2008 proposed rule, the agency proposed a PM standard of 0.046 grams per dry standard cubic meter (g/dscm) (0.020 grains per dry standard cubic foot (gr/dscf)), and proposed to retain the existing 1976 rule's opacity limit of less than 20 percent for thermal dryers constructed, modified or reconstructed after April 28, 2008. The EPA received comments that the PM limit would be prohibitively expensive for modified and reconstructed units to achieve, but that the limit should be lower for new units and should be based on the use of a fabric filter (baghouse).

The agency is now proposing to revise its April 2008 proposal regarding PM and opacity standards for thermal dryers to separate standards for new, reconstructed and modified units. The agency is proposing to revise the limits for new units constructed after April 28, 2008, to 0.023 g/dscm (0.010 gr/dscf) of PM and an opacity limit of less than 10 percent. (PE: Emphasis ours)

For units reconstructed after April 28, 2008, the EPA is proposing to revise the PM limit to 0.045 g/dscm (0.020 gr/dscf) and proposing to maintain the existing 1976 rule's opacity limit of less than 20 percent. For units modified after April 28, 2008, the agency is proposing to maintain the existing 1976 rule's PM limit of 0.070 g/dscm (0.031 gr/dscf) and the existing 1976 rule's opacity limit of less than 20 percent.

SO2, NOx, and CO emission limits for thermal dryers

The existing NSPS does not limit emissions of SO₂, NO_X, or CO from coal preparation facilities, and in the April 2008 proposed rule, the EPA did not propose to add limits for these pollutants. A commenter suggested that standards should be established for each pollutant because thermal dryers emit these pollutants and can cause or contribute significantly to air pollution which may reasonably be anticipated to endanger public health or welfare. The commenter also said using AP-42 emission factors, a 2,000 ton/hr coal thermal dryer would emit 12,000 tons/yr SO₂ and 1,400 tons/yr NO_X, and because cost-effective controls exist the EPA should base requirements on the use of those controls.

For owners/operators of thermal dryers constructed, modified or reconstructed after May 27, 2009, the EPA is proposing to add the following emissions limits: for new, reconstructed, and modified units, an SO₂ limit of 85 nanograms per Joule (ng/J) (0.20 pounds per million British thermal units (lb/MMBtu)), or 50-percent reduction of potential SO₂ emissions and no more than 520 ng/J; for new units, a combined NO_X and CO limit of 280 ng/J (0.65 lb/ MMBtu); for reconstructed units and modified units, a combined NO_X and CO limit of 430 ng/J (1.0 lb/MMBtu).

PM and opacity limits for pneumatic coal-cleaning equipment, coal processing and conveying equipment, coal storage systems, and transfer and loading systems

The original 1976 rulemaking treated each coal processing and conveying equipment, coal storage systems, and transfer and loading systems operation as a separate affected facility. However, it grouped them together for the purpose of establishing a single emissions standard. This was done, according to the EPA, because all of the affected facilities could use similar control devices and achieve comparable emissions rates. The agency believes that this is still an appropriate approach, explaining, "while each operation is a separate affected facility, all are either fugitive sources or point sources of PM and similar control equipment can be used on each affected facility resulting in comparable emissions. If additional data is submitted during the comment period that justifies different opacity limits for different coal handling operations, we will consider that approach in the final rule."

The agency concluded it is not appropriate to require coal handling equipment processing subbituminous and lignite coals be vented to a control device. In addition, after further analysis, the agency proposed to revise the PM emission limits for pneumatic coal-cleaning equipment and mechanically vented coal handling equipment processing all coal ranks constructed, modified or reconstructed after April 28, 2008, to 0.023 g/dscm (0.010 gr/dscf). In addition, the agency proposed to revise the opacity standard to no greater than 5 percent for all pneumatic coal-cleaning equipment, coal processing and conveying equipment, coal storage systems, and transfer and loading systems that commenced construction, reconstruction, or modification after April 28, 2008.

Links

• For more information, find the entire Federal Register notice (pdf)