PERMIT MEMORANDUM 2003-379-TVR 14
DRAFT
OKLAHOMA DEPARTMENT OF ENVIRONMENTAL QUALITY
AIR QUALITY DIVISION
MEMORANDUM June 10, 2005
TO: Dawson Lasseter, P.E., Chief Engineer, Air Quality Division
THROUGH: David Schutz, P.E., New Source Permit Section
Ing Yang, P.E., New Source Permit Section
THROUGH: Peer Review
FROM: Doug Meese, P.E., New Source Permit Section
SUBJECT: Evaluation of Permit Application No. 2003-379-TVR
Northern Natural Gas Company
Woodward County No. 2 Compressor Station
Section 19-T21N-R20W, Woodward County
Directions: From Woodward, 9.25 miles south on 8th Street
SECTION I. FACILITY DESCRIPTION
The facility has four stationary internal combustion engines in compressor service, a 400-barrel condensate tank, two methanol tanks, several auxiliary tanks, sumps and a barrel for lube oil, used oil and oily water. The applicant states that the facility operates under SIC 4922. The site is a dual-stage compressor station. Gas is received through a suction line, liquids are knocked out by separators, and gas is routed to four compressor units (EU IDs ENG1, ENG2, ENG3, and ENG4). Other equipment at the site includes: a parts washer, storage and loading tanks with less than 10,000-gallon capacities, an air compressor, a pump, and a space heater.
The facility was originally constructed in 1972 and three of the four engines on site are considered “grandfathered” because they were constructed prior to April 1, 1979. The fourth engine installed in 1981 operated for a time under Permit No. 81-073-O which did not include emission limits. However, a permit was not required for this engine due to a policy exemption in effect at that time. Since the facility emits more than 100 TPY of a regulated pollutant, it is subject to Title V permitting requirements and ODEQ regulations. Emission units (EUs) have been arranged into Emission Unit Groups (EUGs) in the following outline.
There is only one operating scenario for the facility. For this scenario, field-grade natural gas is the primary fuel for the engines which are operated continuously.
SECTION II. EQUIPMENT
EUG 1 Grandfathered Internal Combustion EnginesEU / Point / Make/Model / Hp / Serial # / Const. Date
1 / P-ENG1 / Waukesha L3711GHC / 418 / 48502 / 1972
2 / P-ENG2 / Waukesha L3711GHC / 418 / 48503 / 1972
3 / P-ENG3 / Waukesha H2475G / 208 / 52437 / 1977
EUG 2 Internal Combustion Engine
EU / Point / Make/Model / Hp / Serial # / Const. Date
4 / P-ENG4 / Waukesha F2895G / 339 / 337325 / 1981
EUG 3 Tanks
EU / Formerly / Point / Contents /
Barrels
/ Gallons / Const. Date1 / 7 / P-Tank1 / Condensate / 400 / 16,800 / 1978
2 / 5 / P-Tank2 / Methanol / 143 / 6000 / 1992
3 / 6 / P-Tank3 / Methanol / 12 / 500 / 1992 est.
4 / 10 / P-Tank4 / Lube Oil / 48 / 2,000 / 1979
5 / 11 / P-Tank5 / Antifreeze / 12 / 500 / 1992
6 / 9 / P-Tank6 / Used Oil / 12 / 500 / 1992
7 / -- / P-Barrel7 / Used Oil / -- / 55 / 1992 est.
8 / -- / P-Tank8 / Oily Water / 12 / 500 / 1992 est.
9 / -- / P-Sump9 / Oily Water / -- / 90 / 1992 est.
10 / -- / P-Sump10 / Used Oil / -- / 90 / 1992 est.
EUG 4 Fugitives
EU / Type of Equipment / Estimated Number
E-FUG / Valves / 65
“ / Relief Valves / 17
“ / Flanges / 324
“ / Pump Seals / 0
“ /
Compressors
/ 4SECTION III. EMISSIONS
Criteria Pollutants
All four engines are 4-stroke, rich burn. Emissions for the engines are based on continuous operation and manufacturer’s emission data for NOx for units 1 and 2. CO and VOC emissions for all units and NOx emissions from unit 3 are based on AP-42, Table 3.2-1. Emissions of NOx and CO from unit 4 are based on portable engine analyzer emissions testing conducted on this engine. SO2 emissions are negligible due to burning natural gas. All PM is assumed to be PM10. Since emissions of SO2 and PM10 are insignificant, they are not shown in the following table.
EUG 1 & EUG 2 Engine EmissionsEU / NOx / CO / VOC
lb/hr / TPY / lb/hr / TPY / lb/hr / TPY
1* / 8.91 / 39.02 / 7.66 / 33.56 / 0.13 / 0.55
2* / 8.91 / 39.02 / 7.66 / 33.56 / 0.13 / 0.55
3* / 4.41 / 19.32 / 3.79 / 16.61 / 0.06 / 0.27
4** / 9.53 / 41.73 / 7.73 / 33.84 / 0.10 / 0.42
TOTAL / 31.76 / 139.09 / 26.84 / 117.57 / 0.42 / 1.79
* Emissions from these engines are based on AP-42, Table 3.2-1, factors of 10.0, 8.6, and 0.14 g/hp-hr for NOx, CO, and NMHC respectively.
** Emissions from this engine are based on results of portable engine analyzer testing conducted on September 15, 1998 and increased by 30% .
Other VOC emissions result from tanks (the condensate tank and others), piping components fugitives (EU ID E-FUG), and blow-down emissions from the compressors.
EUG 3 Tank Emissions*EU / Point / Capacity / NOx / CO / VOC
Gallons / lb/hr / TPY / lb/hr / TPY / lb/hr / TPY
1 / P-Tank1 / 16,800 / Condensate / --- / --- / --- / --- / 0.31 / 1.34
2 / P-Tank2 / 6,000 / Methanol / --- / --- / --- / --- / 0.01 / 0.09
3 / P-Tank3 /
500
/Methanol
/ --- / --- / --- / --- / ---4 /
P-Tank4
/ 2,000 / Lube Oil / --- / --- / --- / --- / <0.01 / <0.015 / P-Tank5 / 500 / Antifreeze / --- / --- / --- / --- / <0.01 / <0.01
6 / P-Tank6 / 500 / Used Oil / --- / --- / --- / ---
7 / P-Barrel7 / 55 / Used Oil / --- / --- / --- / ---
8 / P-Tank8 / 500 / Oily Water / --- / --- / --- / ---
9 / P-Sump9 / 90 / Oily Water / --- / --- / --- / ---
10 / P-Sump10 / 90 / Used Oil / --- / --- / --- / ---
11 / Loading / --- / Condensate / --- / --- / --- / --- / --- / 0.22
TOTALS / --- / --- / --- / 0.32 / 1.65
* Each of the tanks has insignificant emissions due to low vapor pressure of the contents, capacity, and/or limited throughput. (See Section IV Insignificant Activities)
Estimated VOC emissions (above) of 1.34 TPY for the condensate tank were calculated using the E&P Tank v2.0 program. Flash, working and breathing emissions are all included in this number.
EUG 4 Fugitive VOC Emissions*Equipment /
Count**
/ % VOC C3+ / E. Factor / lb/hr /TPY
Valves: / 60 / 21.57 / 0.00992 / 0.13 / 0.564 / 100.00 / 0.00551 / 0.03 / 0.12
Flanges: / 318 / 21.57 / 0.00086 / 0.06 / 0.26
6 / 100.00 / 0.00024 / 0.00 / 0.01
Relief Valves: / 17 / 21.57 / 0.01940 / 0.07 / 0.31
Pump Seals: / 0 / 100.00 / 0.00529 / 0.00 / 0.00
Compressors: / 4 / 21.57 / 0.01940 / 0.02 / 0.08
Total Fugitive Emissions / 0.31 / 1.34
* Emissions were calculated based on percent VOC in the stream.
** Component count estimated
Emissions are based on oil and gas production facilities gas factors from EPA’s 1995 Protocol for Equipment Leak Emission Estimates (EPA-453/R-95-017). Since there are no federal or state regulations that limit the emissions of VOC from piping components because of the date of construction (1972), these emissions are provided for information purposes only.
Facility Total EmissionsEUG /
Equipment
/ NOx / CO / VOClb/hr / TPY / lb/hr / TPY / lb/hr / TPY
1 & 2 / Engines / 31.76 / 139.09 / 26.84 / 117.57 / 0.42 / 1.79
3 / Tanks / --- / --- / --- / --- / 0.32 / 1.65
4 / Fugitives / --- / --- / --- / --- / 0.31 / 1.34
Totals / 31.76 / 139.09 / 26.84 / 117.57 / 1.05 / 4.78
Toxics and HAPs
AP-42, Section 3.2 lists speciated organic compound emission factors for 4-cycle rich burn natural gas stationary engines. The primary toxic emission of concern is formaldehyde, a Category A air toxic with de minimis levels of 0.57 lbs/hr and 0.60 TPY, and a MAAC of 12 ug/m3. Formaldehyde emissions were calculated using the 4SLB factor of 0.0205 lbs/MMBTU from AP-42 (7/00) and manufacturers data for heat input for each engine. Total formaldehyde emissions are above the de minimis levels for Category A toxics. Ambient impacts of formaldehyde were calculated using EPA’s “SCREEN3” air dispersion model. Conservative stack parameters were used: 8 inches stack diameter, 1,679 acfm flow rate, 1,048oF, and 10 feet above grade. Total maximum 24-hr impact of the engines is calculated to be 4.42 ug/m3 at a distance of 54 meters. Compared to the 12 ug/m3 MAAC, the facility is in compliance. A BACT analysis was not required since all engines were installed prior to 3/9/87. Since there is no dehydrator at this facility only toxic and HAP emissions from the engines are considered.
EUG-1 & EUG 2 Toxic/HAP EmissionsEmission /
Acetaldehyde
/ Acrolein / Benzene / Formaldehyde / Methanol / Total HAPsUnit / TPY / TPY / TPY / TPY / TPY / TPY
ENG-1 / 0.05 / 0.04 / 0.03 / 0.34 / 0.05 / 0.54
ENG-2 / 0.05 / 0.04 / 0.03 / 0.34 / 0.05 / 0.54
ENG-3 / 0.02 / 0.02 / 0.01 / 0.16 / 0.02 / 0.26
ENG-4 / 0.05 / 0.04 / 0.03 / 0.34 / 0.05 / 0.54
TOTALS / 0.16 / 0.13 / 0.09 / 1.18 / 0.18 / 1.86
Emission factors for these 4SRB engines are from AP-42, Table 3.2-3 (7/00).
Total Facility Toxic EmissionsToxic/HAP / CAS / Toxic / HAP / De Minimis / Emissions
No. / Category / Y/N / lb/hr / TPY / lb/hr / TPY
Formaldehyde / 50000 / A / Y / 0.57 / 0.60 / 0.27 / 1.18
Methanol / 67561 / C / Y / 5.60 / 6.00 / 0.04 / 0.18
Acetaldehyde / 75070 / B / Y / 1.10 / 1.20 / 0.04 / 0.16
Acrolein / 107028 / A / Y / 0.57 / 0.60 / 0.03 / 0.13
Benzene / 71432 / A / Y / 0.57 / 0.60 / 0.02 / 0.09
Totals (All are HAPs) / 0.40 / 1.74
Only emissions of Formaldehyde are significant and above de minimis levels.
SECTION IV. INSIGNIFICANT ACTIVITIES
The insignificant activities identified and justified in the application are duplicated. Appropriate record keeping of activities indicated below with “*” is specified in the Specific Conditions.
1. * Stationary reciprocating engines burning natural gas, gasoline, aircraft fuels, or diesel fuel for which are either used exclusively for emergency power generation or for peaking power service not exceeding 500 hours/year.
2. Space heaters, boilers and emergency flares less than or equal to 5 MMBTU/hr heat input (commercial natural gas). Space heaters are in use at this facility but all are less than 5 MMBTUH. There are four natural gas-fired heaters used for heating offices and water at the facility located on site: a 60 MBTUH heater, two 110 MBTUH heaters , and a 55 MBTUH heater.
3. Emissions from stationary internal combustion engines rated less than 50 hp output. The facility’s equipment includes an air compressor (15-hp) and a spray washer (8-hp) powered by internal combustion engines.
4. * Storage tanks with less than or equal to 10,000 gallons capacity that store volatile organic liquids with a true vapor pressure less than or equal 1.0 psi at maximum storage temperature. Several tanks, barrels and sumps at this facility store such miscellaneous materials including lube oil, used oil, and antifreeze. These tanks have capacities less than 10,000 gallons and the vapor pressures of the materials stored are less than 1.0 psi.
5. Gasoline, diesel fuel, aircraft fuel, and fuel oil handling facilities, equipment, and storage tanks except those subject to New Source Performance Standards and standards in OAC 252:100-37-15, 39-30, 39-41, and 39-48, or with a capacity greater than 400 gallons.
6. Emissions from condensate storage tanks with a design capacity of 10,000 gallons or less in ozone attainment areas. The condensate tank at this facility has a capacity of 16,800 gallons which is larger than the exempted range.
7. * Emissions from crude oil and condensate storage tanks with a capacity of less than or equal to 420,000 gallons that store crude oil and condensate prior to custody transfer. The condensate tank (Tank-1) stores condensate prior to custody transfer.
8. * Emissions from storage tanks constructed with a capacity less than 39,894 gallons which store VOC with a vapor pressure less than 1.5 psia at maximum storage temperature. Tanks storing antifreeze, lube oil, used oil and oily water have capacities less than 39,894 gallons and store products having a vapor pressure less than 1.5 psia.
9. Cold degreasing operations utilizing solvents that are denser than air. A parts washer is on site, but uses a solvent with a vapor density heavier than air. A covered 30-gallon parts washer is located on site.
10. Site restoration and/or bioremediation activities of <5 years expected duration. A well and an electric vacuum pump are located on site for site remediation. All recovered hydrocarbons and vapors are routed into a drum of activated carbon.
11. Surface coating and degreasing operations which do not exceed a combined total usage of more than 60 gallons/month of coatings, thinners, clean-up solvents, and degreasing solvents at any one emission unit. None on site currently, but may be in the future.
12. Exhaust systems for chemical, paint, and /or solvent storage rooms or cabinets, including hazardous waste satellite (accumulation) areas. One storage room/cabinet is located on site.
13. Hand wiping and spraying of solvents from containers with less than 1 liter capacity used for spot cleaning and/or degreasing in ozone attainment areas. Routine maintenance on compressor engines might require use of a degreasing solvent sprayed from containers with less than a 1 liter capacity.
14. * Activities (except trivial activities) that have the potential to emit no more than 5 TPY (actual) of any criteria pollutant. The fugitive emissions and the methanol storage tanks fall under this category each having less than 5 TPY of actual VOC emissions.