INFORMATION RELATIVE TO
THE DRAFT TITLE V OPERATING PERMIT
February 22, 2013

FOR:
Transcontinental Gas Pipe Line Company LLC, Station 77
Highway 535 North
Seminary, MS 39479    

FACILITY DESCRIPTION
Transcontinental Gas Pipeline Company LLC, Station 77 is an existing natural gas compressor station and natural gas storage facility in Seminary, Mississippi (Covington County).  The facility handles 4.93 million standard cubic feet per day of natural gas.  The facility consist of four (4) natural gas compressor engines, one (1) natural gas emergency generator, one (1) indirect heater, six (6) water bath heaters, five (5) glycol dehydration reboiler units, two (2) natural gas starters, and eight (8) flares. The permit actions are to renew the Title V Permit and modify the Title V Permit as a significant modification, which will not trigger a Prevention of Significant of Deterioration (PSD) Review.

TITLE V PROGRAM APPLICABILITY BASIS
Transcontinental Gas Pipeline Company LLC, Station 77 is a major source as defined by Title V of the Federal Clean Air Act due to its potential to emit more than 100 tons per year of each of the following criteria air pollutants: nitrogen oxides (NOx), carbon monoxide (CO), and its potential to emit more than 10 tons per year of the hazardous air pollutant formaldehyde.

GREENHOUSE GAS (GHG) APPLICABILITY
The facility’s potential-to-emit for CO2e (non-biogenic only) is 155,271 tons/year; therefore, the facility is a major source of GHGs.  Total CO2e emissions (both non-biogenic and biogenic) are 155,271 tpy.  Because there are no applicable federal standards for GHGs and no PSD or PSD-avoidance permits have been issued for GHGs, there are no specific GHG requirements in this Title V permit.

LEGAL AND FACTUAL BASIS FOR DRAFT PERMIT CONDITIONS

The State and Federally-enforceable conditions of Title V Operating Permits are based upon the requirements of the State of Mississippi Air Emissions Operating Permit Regulations for the Purposes of Title V of the Federal Clean Air Act (APC-S-6), and applicable requirements effective upon the date of permit issuance.  Applicable requirement means all of the following as they apply to emissions units in a Title V source:

1.	any standard or other requirement set forth in the State Implementation Plan (SIP) approved or promulgated by EPA through rulemaking under Title I of the Federal Clean Air Act (Federal Act) including the following:

a.	most of the State of Mississippi Air Emission Regulations for the Prevention, Abatement, and Control of Air Contaminants (APC-S-1) ,
b.	the State of Mississippi Regulations for the Prevention of Air Pollution Emergency Episodes (APC-S-3),
c.	the State of Mississippi Regulations for the Prevention of Significant Deterioration of Air Quality (APC-S-5), and 40 CFR Part 52.21 by reference, and
d.	the provisions of the State of Mississippi Permit Regulations for the Construction and/or Operation of Air Emissions Equipment (APC-S-2), relating to construction permits and synthetic minor operating permits;

2.	any term or condition of any construction permits issued pursuant to Mississippi regulations approved or promulgated through rulemaking under Title I;

3.	any standard or other requirement under Section 111 of the Federal Act, including Section 111(d) which includes Title 40, Part 60 of the Code of Federal Regulations (40 CFR Part 60) and relevant sections of APC-S-1;

4.	any standard or other requirement under Section 112 of the Federal Act, including relevant sections of APC-S-1 and 40 CFR Parts 61, 63, and 68;

5.	any standard or other requirement of the acid rain program under Title IV of the Federal Act or the regulations promulgated thereunder, including the State of Mississippi Acid Rain Program Permit Regulations for Purposes of Title IV of the Federal Clean Air Act (APC-S-7)  adopted November 17, 1994, and 40 CFR Parts 72, 73, 75, 77, and 78;

6.	any requirements established pursuant to Section 504(b) or Section 114(a)(3) of the Federal Act;

7.	any standard or other requirement governing solid waste incineration under Section 129 of the Federal Act;

8.	any standard or other requirement for consumer and commercial products under Section 183(e) of the Federal Act;

9.	any standard or other requirement for tank vessels under Section 183(f) of the Federal Act;

10.	any standard or other requirement of the program to control air pollution from outer continental shelf sources under Section 328 of the Federal Act;

11.	any standard or other requirement of the regulations promulgated to protect stratospheric ozone under Title VI of the Federal Act;

12.	any national ambient air quality standard or increment or visibility requirement under part C of Title I of the Federal Act.

Each State and Federally-enforceable condition of the draft Title V Operating Permit references the specific relevant requirements of APC-S-6 or the applicable requirement upon which it is based. Any condition of the draft Title V permit that is enforceable by the State but is not Federally-enforceable is identified in the draft Title V permit as such.

CAM APPLICABILITY
There is no control equipment associated with any of the emission units subject to an emission standard at this facility, therefore, Compliance Assurance Monitoring does not apply to Transcontinental Gas Pipeline Company LLC, Station 77.

MACT APPLICABILITY

MACT Subpart HHH – National Emission Standards for Hazardous Air Pollutants from Natural Gas Transmission and Storage Facilities was promulgated on June 17, 1999.  The facility has five emission points subject to this MACT.  They are AA-008, AA-010, AA-013, AA-015, and AA-017.  A final rule was issued on August 16, 2012 to revise 40 CFR 63 Subpart HHH which removes the previous 0.90 megagrams of benzene per year exemption threshold requiring applicable small dehydration units to comply with the standard.  Units that meet the definition of a small glycol dehydration unit located at a major source of HAP that commenced construction before August 23, 2011, must achieve compliance no later than October 15, 2015

MACT Subpart ZZZZ – National Emission Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines (RICE) was promulgated on June 15, 2004.  Since the facility has stationary reciprocating internal combustion engines and it is major for HAPs, the MACT standard will apply.  There are a total of four reciprocating internal combustion engines and two emergency generators located at the site.  Emission Points AA-001 though AA-003, are existing 2 Stroke Lean Burn engines.  Existing 2 SLB engines do not need to comply with any of the requirements of the General Provisions [40 CFR 63.6665], and existing 2 SLB engines do not need to comply with the emission limitations in Tables 1a and 2a of this subpart or operating limitations in Tables 1b and 2b of this subpart [40 CFR 63.6600(c)].  The compliance date for an existing stationary RICE is set for June 15, 2007.  Beginning that compliance date, Emission Point AA-004 will be designated as a 4 Stroke Rich Burn Emergency Natural Gas-Fired Compressor Engine.  Emergency stationary RICE do not need to comply with the emission limitations in Tables 1a and 2a of this subpart or operating limitations in Tables 1b and 2b of this subpart, nor do Emergency stationary RICE need to comply with any of the requirements of the General Provisions [40 CFR 63.6665].  Condition 5.B.8 and 5.C.6 have been placed in the permit to address this change.  This condition requires the hours of operation and reason for operation to be recorded and reported.  
For Emission Point AA-021, the permittee must reduce CO emissions by 93%.

There is one 100 HP natural gas fired emergency air compressor engine that is an insignificant activity that are subject to MACT ZZZZ. The permittee shall comply with the work practice standards in 40 CFR 63.6595(a)(1) Table 2c by October 19, 2013. 
MACT Subpart DDDDD - National Emissions Standards for Hazardous Air Pollutants for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and Process Heaters was promulgated on September 13, 2004.  The facility has twelve units heaters and reboilers that are subject to this MACT.  The units are AA-005 through AA-010 and AA-012 through AA-017.  A final rule was issued on January 31, 2013 to revise 40 CFR 63 Subpart DDDDD.  Applicability of this recently revised regulation is being evaluated and permitee shall comply with the updated requirements of 40 CFR 63 Subpart DDDDD by the applicable compliance deadlines.

NSPS Subpart JJJJ- New Source Performance Standards for Stationary Spark Ignition Internal 
Combustion Engines was promulgated January 18, 2009.  For Emission Point AA-021, the 
permittee is subject to the requirements of this Subpart. The permittee shall comply with the 
standards in 40 CFR 60.4233.

SPECIFIC APPLICABLE REQUIREMENTS

Transcontinental Gas Pipe Line Company, Seminary Station 77 has requested a significant modification to the Title V permit to add up to eight (8) flares with each flare not to exceed 10MMScf/day of gas flared. This modification is related to the December 26, 2010 event at the facility.

On December 26, 2010, Transco detected a pressure drop in Cavern 3. Since that time, Transco has been involved in an emergency response which has resulted in the removal of natural gas from several of the storage caverns and from the subsurface strata via production to the pipeline, venting to the atmosphere, and flaring, as detailed in reports to MDEQ. These activities have been conducted under the oversight of the Mississippi Department of Environmental Quality, as formalized in Agreed Order 6033 11 dated October 5, 2011. At present, there are four flares connected to monitoring wells at the facility, although only the flare connected to Well MW237SD is actually flaring. Additional flares may be needed if additional pockets of subsurface gas are encountered which have sufficient volume and pressure for flaring. Current
estimates show up to 350 million standard cubic feet (MMscf) of natural gas is in the caprock above the salt dome and up to 30 MMscf of natural gas in the more shallow strata. Regardless of these preliminary estimates, Transco proposes to flare, to the extent practicable, any subsurface natural gas, as necessary, but at a rate not to exceed 342MMscf per calendar year. The flares shall operate at flare gas high heat value of at least 300 But/scf. In addition the state H2S standard of one (1) grain per 100 standard cubic feet (gr/100 scf) is applicable.

The facility is an existing major source as defined by “Mississippi Regulations for the Prevention of Significant Deterioration (PSD) of Air Quality”, APC-S-5.  The project will result in increased emissions of Nitrogen Oxides (NOx), Carbon Monoxide (CO), Particulate Matter (PM), Sulfur Dioxide (SO2), Hydrogen Sulfide (H2S), Greenhouse Gases (GHG), and Volatile Organic Compounds (VOC) less than the PSD significant rates.  Below are the potential emission summary for the flaring:

Pollutant	Potential Emissions (tons/yr)	Major Modification Emission Rate (tons/yr)	Emission as Percentage of Major Modification Emission Rate	
NOx	12.0	40	30%	
CO	64.8	100	65%	
PMtotal	0.0062	25	<1%	
SO2	16.0	40	40%	
VOC	3.33	40	8%	
H2S	0.17	10	2%	
GHG	25,542	75,000	34%	

Transcontinental Gas Pipe Line Company, Seminary Station 77 is requesting to increase operating hours from 5,500 hrs/yr to 8760 hrs/yr for the glycol dehydrator units (AA-008, AA-010, AA-013, AA-015, and AA-017). This change will not trigger PSD permitting since the total potential emission increase associated with the change does not exceed PSD significant emission rate thresholds for any of the affected pollutants.

Transcontinental Gas Pipe Line Company, Seminary Station 77 was issued a Prevention of Significant Deterioration Construction Permit on May 28, 2009 to construct for a 4,735 HP natural gas internal combustion compressor engine and two (2) natural gas starters for the engines.  This new compressor unit would provide additional horsepower needed to increase the injection rate of natural gas into underground caverns for storage and withdrawal and increase utilization of the existing equipment at the facility that would result in an actual increase in emissions (debottlenecking). The project will result in increased emissions of Nitrogen Oxides (NOx), Carbon Monoxide (CO), and Volatile Organic Compounds (VOC) greater than the PSD significant rates.  The permit included a Best Available Control Analysis and included these limits in the permit.

EMISSION LIMITS	
Emission Point No.	Pollutant	Draft Permit Emission Limits	Monitoring Requirements	
AA-024	Operational Restriction	The permittee shall not exceed flare rate of 342 MMSCF/yr of recovered natural gas. The permittee shall maintain flare gas high heat value of at least 300 BTU/scf	The permittee shall submit certification of construction/installation. The certification for the new flares shall include: 1) when a flare is constructed; and 2) the flare is capable of complying with the standards and limitations in this permit. For the new flares, the permittee shall maintain documentation of flare specifications on site. For the flares at the site, the permittee shall submit five (5) days in advance of when a flare is moved at the site, except that in emergency such notification shall be submitted within two (2) business days after the installation . The notification shall contain a description of where the flare was and where is going, and why the flare is being moved. 

The permittee shall measure and record daily: 1) the  volumetric flow rate of the recovered natural gas of each flare; 2) the start, end, and duration of each flare event for each flare.
The permittee shall keep records of maintenance performed on the flares.

	
	
AA-024	H2S	The permittee shall not cause or permit the emissions for any gas stream which contains hydrogen sulfide in excess of one (1) grain per 100 standard cubic feet (gr/100 scf). 
	The permittee shall conduct monthly recovered natural gas    analysis including hydrogen sulfide concentration, heating value (Btu content).	
AA-021	NOx	0.5 g/hp-hr, not to exceed 5.21 lb/hr and 22.84 tons/yr	The permittee shall stack test for NOx and CO within 180 days of startup	
	CO	0.055 g/hp-hr, not to exceed 0.57 lb/hr and 2.51 tons/yr		
	VOC	0.12 g/hp-hr, not to exceed 1.24 lb/hr and 5.41 tons/yr		
AA-021	PM/PM10	1.59 tons/yr	The permittee shall stack test for PM/PM10 .  The emission factor derived from the stack test shall be used to calculate and record the PM/PM10 emissions on a 12 month rolling average.  This report shall be submitted semi-annually. 	
AA-021	Operational Restriction	Shall only operate engine with oxidation catalyst 	
The permittee shall report any deviations from the emission limitation or any occurrences where the compressor engines operated without the oxidation catalyst.  This report shall include the time, date, reason for the deviation, and corrective actions or preventive measures taken.  The report shall be submitted with five (5) days of the time the deviation began.

During the stack test for CO, the permittee shall monitor the inlet and outlet temperature of the catalyst bed.  The unit shall operate at maximum production during this test and engine operating load data shall be collected during the test.  	
AA-001 through AA-003, AA-007, AA-009, AA-012, AA-014, AA-016, AA-024	PM	E=0.8808*I-0.1667	Monitor and record fuel type, sulfur content and heating value of fuel used	
AA-004, AA-005, AA-008, AA-010, AA-013, AA-015, AA-017	PM	0.6 lbs/MMBTU		
AA-001 through AA-017	SO2	4.8 lbs/MMBTU		
AA-001 through AA-010, AA-012 through AA-017	Fuel Restriction	Combustion of Natural Gas only		
 AA-008, AA-010, AA-013, AA-015, AA-017	Benzene	Operation of the vapor recovery system.	Determine and record actual annual average benzene emissions. Inspection and maintenance of control equipment.
Record the date, start time, and duration of any failure of the control equipment and/or bypass of the vapor recovery unit.	
AA-004	Operational Restriction	500 hours per 12 month rolling total	Monitor and record emergency and non-emergency use operating hours on a monthly basis and a 12 month rolling total basis.  The record should include the type of emergency, if it is an emergency situation and any other reason for operation.	

The facility’s emission points listed in the permit are natural gas fired.  These emission points are subject to the state standards for PM, SO2 and Opacity.  Since these units use natural gas, the margin of compliance is so large that no associated monitoring or reporting was placed in the permit.  The facility will have to maintain records of the type and quality of fuels used to demonstrate the fuel type used.