United States Environmental Protection Agency, Regi on 9

Air Division

Technical Support Document

for

EPA’s Notice of Proposed Rulemaking

for the

California State Implementation Plan

San Joaquin Valley Unified Air Pollution Control Di strict’s

Rule 4352, Solid Fuel Fired Boilers, Steam Generato rs and Process Heaters

Prepared by: Idalia Perez

October 2009- 2

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San Joaquin Valley Unified Air Pollution Control Di strict (SJVAPCD)

Submitted Rule SJVAPCD Rule 4352, Solid Fuel Fired Boilers, Steam Generators and Process Heaters

• Adopted: May 18, 2006

• Submitted: October 5, 2006

• Determined complete: October 24, 2006 EPA published a proposal and direct final approval of this rule on May 30, 2007 (72 FR 29886). We received adverse comments and consequently withd rew the direct final approval (72 FR 41450).

Previous Rule Submittals There are no outstanding submittals of Rule 4352.

SIP-Approved Rule

• Adopted: October 19, 1995

• Approved by EPA: February 11, 1999 (64 FR 6803)

Rule Summary
Rule 4352 limits NOx and CO emissions from solid fu el fired boilers, steam generators and process heaters. The facilities in SJVAPCD that ar e subject to Rule 4352 burn a variety of fuels including biomass, agricultural waste, wood waste, coal, tire derived fuel, petroleum coke and municipal solid waste (MSW). The submitted rule re visions include:

• More stringent applicability threshold: the revised rule applies to solid fuel-fired boilers, steam generators, or process heaters located at sou rces that have potential NOx or VOC emissions of at least 10 tons per year (tpy), which is lower than the applicability threshold of 50 tpy in the SIP rule.

• More stringent NOx emission limits for units firing biomass and other non-MWS solid fuels, in Section 5.1.

• Alternative requirements for start-up and shutdown operations in Section 5.3.

• New provisions authorizing the APCO, ARB, and EPA t o approve an owner/operator’s request (accompanied by appropriate justification) for an increased emission limit for a unit operated at less than 50 percent of rated heat input, in Section 5.4.

• Various minor clarifications.

Sources and Rule Requirements The following are the uncontrolled NOx emissions fr om this source category, according to the 1994 ACT for ICI boilers (see Guidance Document #5, Table 2-2): Fuel Boiler Type Uncontrolled NOx (lb/MMBtu) Approximate

ppm at 3% O 2 Coal Fluidized bed combustor (FBC) 0.14 – 0.60 109 – 466

Wood > 70 MMBtu/hr 0.17 – 0.30 124 – 218

MSW Mass burn 0.40 300- 3

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The following are the levels to which NOx emissions may be controlled for units with Selective Non-Catalytic Reduction (SNCR with ammonia injectio n), according to the 1994 ACT for ICI boilers (see Guidance Document #5, Tables 2-6): Fuel Boiler Type Controlled NOx (lb/MMBtu) Approximate

ppm at 3% O 2 Coal FBC 0.04 – 0.09 29 – 65

Wood FBC 0.03 – 0.20 23 – 155

MSW Stoker and mass burn 0.07 – 0.31 52 – 232

Effective January 1, 2007, Rule 4352 limits NOx emi ssions from MSW-fired units to 200 ppm at
12% CO 2 (about 266 ppm at 3% O 2 ) and NOx emissions from units fired by all other s olid fuels, including biomass, to 115 ppm at 3% O 2 . Both the SIP rule and the revised rule require t hat the NOx emission limits be averaged over 24 hours.

SJVAPCD provided EPA with a list of permitted units subject to Rule 4352 (Attachment #6). This list identifies one facility subject to the em ission limits for MSW in Rule 4352, and 13 facilities burning coal, coke, biomass or other fue ls that are subject to the emission limits for all
other solid fuels. This list also indicates that a ll of these units have installed and are operating SNCR equipment.

Effect on Emissions SJVAPCD’s staff report (Attachment #3) does not cla im emission reductions from implementation of these rule revisions, as all unit s subject to Rule 4352 already comply with the NOx emission limits that became effective locally o n January 1, 2007.

Rule Evaluation Criteria Generally, SIP rules must be enforceable (see §110( a) of the Clean Air Act, hereafter CAA); must require Reasonably Available Control Technolog y (RACT) for major sources of NOx in nonattainment areas (see CAA §182(b)(2) and (f)); m ust not interfere with applicable requirements, including requirements concerning att ainment (see CAA §110(l)); and must not relax existing requirements in effect prior to enac tment of the 1990 CAA amendments (see §193).

SJVAPCD regulates an extreme nonattainment area for the 1-hour ozone standard and a serious nonattainment area for the 8-hour ozone standard (4 0 CFR 81), so submitted Rule 4352 must fulfill RACT requirements. Rule 4352 must also requ ire the use of advanced control technologies to control NOx emissions from this source category (see CAA §182(e)(3)).

Guidance and policy documents that we used to defin e enforceability and RACT requirements include the following:

1. Issues Relating to VOC Regulation, Cutpoints, Defic iencies, and Deviations (the "Blue Book"), US EPA, OAQPS (May 25, 1988).

2. Guidance Document for Correcting Common VOC and Oth er Rule Deficiencies , EPA Region IX (August 21, 2001, the “Little Bluebook”).- 4

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3. State Implementation Plans; General Preamble for th e Implementation of Title I of the Clean Air Act Amendments of 1990, 57 FR 13498 (April 16, 1992); 57 FR 18070 (April 28, 1992).
4. State Implementation Plans; Nitrogen Oxides Supplem ent to the General Preamble; Clean Air Act Amendments of 1990 Implementation of Title I; Proposed Rule, 57 FR 55620, November 25, 1992 (the NOx Supplement).
5. Determination of Reasonably Available Control Techn ology and Best Available Retrofit Control Technology for Industrial, Institutional, a nd Commercial Boilers, Steam Generators, and Process Heaters , CARB (July 18, 1991). http://www.arb.ca.gov/ractbarc/boilers.pdf

6. Alternative Control Techniques Document-- NOx Emiss ions from Industrial/Commercial/Institutional (ICI) Boilers

, US EPA 453/R-94-022 (March 1994). http://www.epa.gov/ttn/catc/dir1/icboiler.pdf

7. Alternative Control Techniques Document-- NOx Emiss ions from Utility Boilers , US EPA 453/R-94-023 (March 1994). http://www.epa.gov/ttn/catc/dir1/utboiler.pdf

SJVAPCD is currently designated attainment for PM 10 (40 CFR 81.305). Accordingly, SJVAPCD is not subject to the requirement to implem ent BACM for PM 10 and PM 10 precursors in CAA § 189(b) and (e). Therefore, we are not eval uating Rule 4352 for compliance with BACM requirements.

Discussion of Enforceability and Relaxation Criteri a We believe the submitted rule revisions adequately fulfill most of the relevant criteria identified above. Specifically:

• Recordkeeping and other compliance provisions in th e rule ensure that the requirements are adequately enforceable.

• The change in the applicability threshold from 50 t py to 10 tpy significantly expands the rule’s applicability.

• Inclusion of more stringent NOx emission limits mak e the submitted rule more stringent than the version previously approved into the SIP, so the submitted rule does not relax the SIP and complies with CAA §110(l) and §193.

Discussion of Advanced Control Technology Section 182(e)(3) of the Act requires that SIPs for extreme ozone nonattainment areas contain provisions requiring that each new, modified, and e xisting electric utility and industrial and commercial boiler that emits more than 25 tpy of NO x either: (1) burn as its primary fuel a clean fuel (natural gas, methanol, or ethanol, or a comparably low polluting fuel), or (2) use advanced control technology (such as catalytic cont rol technology or other comparably effective control methods) to reduce NOx emissions. We believe the term "catalytic control technology" was intended generally to refer to sele ctive catalytic reduction (SCR).

Rule 4352 applies to commercial and industrial boil ers (in addition to other types of emission units) at facilities that potentially emit 10 tpy o r more of NOx, which includes all boilers that emit more than 25 tpy of NOx. All of the NOx emiss ion limits in the revised rule effectively require operation of Selective Noncatalytic Reducti on (SNCR) control systems. We believe SNCR is "comparably effective" to SCR for the affec ted sources as discussed below, and thus- 5

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fulfills Section 182(e)(3) requirements for these a ffected sources. SNCR also appears to achieve NOx emission reductions comparable to combu stion of clean fuels at these types of
boilers.

According to information in the RACT/BACT/LAER Clea ringhouse, recent Prevention of Significant Deterioration (PSD) permits contain emi ssion limits for coal-fired boilers ranging from 0.067 lbs/MMBtu (for large coal-fired boilers with SCR and low-NOx burner technology) to 0.1 lbs/MMBtu (for medium-sized coal-fired boile rs with SNCR). These limits reflect Best Available Control Technology (BACT) determinations under the PSD program. According to the 1994 ACT for ICI boilers (see Guidance Document #5, Tables 2-6), wood-fired watertube
boilers with SCR can achieve NOx emissions of 0.22 lb/MMBtu. The 1994 ACT does not
contain emission levels for wood-fired FBC boilers with SCR but states that this type of unit with SNCR can achieve NOx emission limits ranging f rom 0.03 to 0.20 lb/MMBtu.

Our review of these emission ranges indicates that although emission rates can vary according to fuel type and boiler size, generally SNCR contro ls are comparably effective to SCR for boilers firing wood (biomass), MSW, and many other types of solid fuels. As a general matter, SNCR is also comparably effective to SCR control fo r circulating fluidized bed coal-fired boilers of less than 50 MW electric generation capa city. For coal-fired boilers, we have focused our review on circulating fluidized bed boi lers of less than 50 MW generation capacity because all existing coal-fired boilers in SJV are of this type and below this size. The emission levels achieved by SNCR control systems are also ge nerally comparable to the uncontrolled NOx emissions from boilers firing clean fuels such as natural gas, which may range from 0.07 to 0.45 lb/MMBtu (see Guidance Document #5, Table 2 -2). SNCR control systems consistently achieve up to 80% NOx emission reducti ons and are compatible with almost all solid fuel-fired boiler operations, while other con trols may in some cases be sensitive to catalyst poisoning and other technical constraints. As to boilers that emit above 25 tpy of NOx, we note as a practical matter that only existing bo ilers in SJV are likely to be constrained by the NOx emission limits in Rule 4352, as all new boiler s that potentially emit above 25 tpy and all major modifications at existing boilers will also b e subject to the more stringent control technology requirements of the Nonattainment New So urce Review (NNSR) or PSD permit programs. The requirements of Rule 4352 are genera lly applicable to this source category and do not supplant any more stringent control requirem ents that apply on a case-by-case basis under the NNSR or PSD permit programs.

Discussion of RACT Criteria On April 16, 2009, SJVAPCD adopted its “2009 RACT S IP” to demonstrate that RACT is implemented for all appropriate activities (see Att achment #5 for relevant pages). In summary,
SJVAPCD found that Rule 4352 met or exceeded the an alogous NSPS, and found no applicable CTG, NESHAP or MACT standards. The document also c ompared Rule 4352 to analogous rules in other large California nonattainment areas including South Coast, Bay Area, Sacramento and Ventura. These rules contain a 40 ppm limit for non-gaseous fuels. Sacramento Rule 411 includes a 70 ppm limit at 12% CO 2 (about 100 ppm at 3% O 2 ) for biomass fuels. SJVAPCD states that these limits are more stringent than Ru le 4352, but have not been demonstrated for
solid fuel-fired units because there are no boilers in the Sacramento area that fire solid fuels.- 6

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Furthermore, SJVAPCD states that the 40 ppm limit f or non-gaseous fuels in ARB’s RACT/BARCT guidelines was never intended for applic ation to solid fuel-fired units.

We concur with SJVAPCD’s conclusion that Rule 4352 implements RACT for units fired with biomass fuels for reasons including:

• The relevant Rule 4352 requirements are more string ent than both 1994 ACT documents listed above. ACT documents provide technical info rmation on available controls and are often used to help define RACT.

• No facilities in Sacramento currently operate boile rs that meet the 70 ppm limit for biomass-fired units in Rule 411, so this limit has not been shown to be technologically feasible. (Email from Jorge de Guzman at Sacramento Metropolitan AQMD to Roger Kohn at EPA on September 10, 2009).

• We have no information indicating that the 40 ppm l imit for non-gaseous fuels in other districts’ rules has been demonstrated to be genera lly technologically feasible for biomass
fuel-fired units.

• According to Attachment #6, all permitted units sub ject to Rule 4352 are equipped with SNCR. We believe SNCR technology generally achieves a RACT level of control for this source category as it is effective at reducing NOx emission and is, to our knowledge, the only technique that is currently widely available f or this source category.

We do not believe, however, that SJVAPCD has adequa tely demonstrated that the Rule 4352 NOx emission limits for units fired with MSW (appro ximately 266 ppm at 3% O 2 ) and for units fired with coal/coke and other solid fuels (i.e., solid fuels other than MSW and biomass) (115 ppm at 3% O 2 ) achieves a RACT level of control for these source categories, for reasons including:

• The 1994 ACT for ICI boilers (Guidance Document #5) indicates that lower NOx emissions should be reasonably achievable with SNCR controls that existing units subject to Rule 4352 currently have installed.

• SJVACPD does not provide sufficient information to demonstrate that the emission ranges present in the 1994 ACT for ICI boilers are not reasonably achievable or other
information to demonstrate that Rule 4352 satisfies RACT requirements.

• Source test data for the one existing MSW facility in the San Joaquin Valley suggests that emission limits lower than required by Rule 4352 ar e reasonably achievable (see Attachment #7). In 1994, units 1 and 2 tested at a n average of 139 ppm and 129 ppm at
12% CO 2 . In 2009, they tested at an average of 146 ppm and 143 ppm at 12% CO 2 . It is not clear why a limit close to those ranges, consis tent with the 1994 ACT is not appropriate for RACT.

• Emission limits for permitted coal-burning faciliti es in Attachment #6 suggest that limits lower than contained Rule 4352 are reasonably achie vable. Specifically, Attachment #6 identifies only one existing facility with a permit emission limit above 0.1 lb/MMBtu (approximately 75 ppm at 3% O 2 ).

• For coal fired units, the ACT also states that unit s with ammonia injection should be able to achieve lower emissions than the 115 ppm at 3% O 2

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• While we believe that SNCR may represent RACT for t hese sources, and the NOx limits in the existing rule effectively require SNCR, we n onetheless believe it is appropriate to- 7

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require more stringent emission limits in Rule 4352 to ensure that facilities maintain good operating and maintenance practices consistent with CAA RACT requirements.

Rule Deficiency

• SJVAPCD has not demonstrated that the emission limi ts for units firing MSW fuels or other non-biomass solid fuels implement RACT. The NOx emission limits for these source categories in Rule 4352 should be lowered to ensure implementation of RACT. Alternatively, SJVAPCD may submit additional inform ation to demonstrate that lower emission limits are not reasonably achievable.

Suggested Rule Improvement EPA recommends that the SJVAPCD make the following improvements in the next revision of
Rule 4352:

1. The term flame stabilization period in Section 2.0 should be clearly defined in the Ru le.

2. Section 5.4.2 should indicate that source test info rmation at the reduced load should be included in a request for increased emission limits for units operating at less than 50% of the rated heat input.

3. The term normal operations in Section 6.3.2 should be clearly defined in the Rule or the Rule should state that it must be defined in the pe rmit to operate.

4. The Rule does not specify required controls for dir ect PM2.5 emissions. These should be added in subsequent revisions of the Rule.

Recommendation EPA staff recommends limited approval and limited d isapproval of SJVAPCD’s submitted rule 4352 for incorporation into the San Joaquin Valley portion of the California SIP.

Attachments
1. Submitted Rule 4352 (Clean Copy, Adopted May 18, 20 06)
2. Submitted Rule 4352 (Strikeout Copy, Adopted May 18 , 2006)
3. Staff Report (Adopted May 18, 2006)
4. SIP-approved version of Rule 4352 (Adopted October 19, 1995)
5. SJVAPCD RACT Demonstration for Ozone SIP, pages 4-6 1 – 4-68 (Adopted April 16, 2009)

6. List of Solid Fired units in SJVAPCD

7. Source Test Report summaries for MSW facility