PERMIT MEMORANDUM 2002-395-O (M-2) 2

OKLAHOMA DEPARTMENT OF ENVIRONMENTAL QUALITY

AIR QUALITY DIVISION

MEMORANDUM January 3, 2005

TO: Dawson Lasseter, P.E., Chief Engineer, Air Quality

THROUGH: David Schutz, P.E., New Source Permits Section

THROUGH: Ing Yang, P.E., New Source Permits Section

THROUGH: Peer Review

FROM: Kha Mach, E.I., Existing Source Permits Section

SUBJECT: Evaluation of Permit Application No. 2002-395-O (M-2)

Continental Gas, Inc.

Matli Compressor Station

Section 5, Township 16N, Range 11W, IM

Watonga, Blaine County, Oklahoma

Driving Directions: From intersection of State Hwy 33 and State Hwy 8 in Watonga, OK, 3 mi. North, 3 mi. East, ½ mi. North, 1000 ft West into site.

INTRODUCTION

Continental Gas, Inc. (CGI) has requested an operating permit for the air pollutant emitting activities at the Matli Compressor Station. The facility is operating under Permit No. 2002-395-C (M-2) dated June 12, 2003. The facility is classified as a natural gas processing plant (NAIC code 211112, SIC code 1321). The applicant applied for Part 70 operating permit as partial solution from the violation in NOV No. 1339 dated July 14, 2003. There are some minor changes from Permit No. 2002-295-C (M-2) contained in this permit, both in the equipment present at the site and in the methods of calculation of emissions. The TEG dehydration unit, i.e. 0.225 MMBTUH heater (emission points H-1 and V-1) and Kimray 9015PV glycol pump, have been replaced with larger units, i.e. 0.550 MMBTUH heater and Kimray 21015PV. This dehydration unit is not subject to NSPS or NESHAP, and generates a VOC emission increase of less than 5 TPY, so a construction permit modification was not required. Another change is a correction of the calculation used for deriving fugitive VOC emissions, taking a vapor recovery unit into account. Other minor changes include (a) corrections in the Btu content of the fuel gas, (b) a correction in the size of the condensate storage tank, (c) a correction in the flow rate through the EG dehydration unit. None of the changes create a change in the “synthetic minor” source status of the facility

FACILITY DESCRIPTION

The facility is a natural gas gathering compressor station and processing plant, operating 8,760 hours annually. There are two discrete inlet streams entering the compressor station. One stream is a low pressure (50 psig), 1,115-Btu/scf lean gas with 40 ppmv of H2S. The other is a high pressure (800 psig), 1,185-Btu/scf rich sweet gas containing no H2S. The lean gas is compressed with five catalytically controlled compressors. After compression, the gas passes through an H2S treater and TEG dehydration unit before entering the sales line. Condensate removed by the compressor suction scrubbers is piped to the two 210-bbl condensate tanks for temporary storage before being trucked from the site.

The high-pressure rich gas entering the facility proceeds directly to the natural gas liquids (NGLs) extraction plant for processing. The extracted NGLs are stored in pressurized storage tanks before being trucked or pipelined from the site. Contained within the NGL plant is a propane refrigeration compressor (driven by a catalytically controlled Caterpillar G342 compressor engine) and an EG dehydration unit. Following liquids extraction and dehydration, the gas flows into the sales line. The facility emission units are tabulated in Table 1.

Table 1 - Description of the Emission Units

ID #

/ Emission Unit Name/Model / Installation Date
C1 / 800-hp Superior 8G825 Compressor Engine w/CC 1 (SN: 20231) / Sept 1999
C2 / 800-hp Superior 8G825 Compressor Engine w/CC 1 (SN: 18524) / 2003
C3 / 800-hp Superior 8G825 Compressor Engine w/CC 1 (SN: 20170) / Oct 2002
C4 / 1,232-hp Waukesha L7042 GSI Compressor Engine w/CC 1 (SN: 263049) / May 2003
C5 / 877-hp Waukesha L5790 GU Compressor Engine w/CC 1 (SN: 402196) / May 2003
C6 / 225-hp Caterpillar G342 Compressor Engine w/CC 1 (SN: 4B04032) / 2003
SU / Sulfur Treatment Sweetening Unit 2 / After 1984
H1 / 0.550 MMBTUH Glycol Reboiler / Aug. 2003
V1 / Glycol Regenerator Vent with condenser / Aug. 2003
H2 / 0.750 MMBTUH Glycol Reboiler / Sept. 2003
V2 / Glycol Regenerator Vent / Sept. 2003
T1 / 210-bbl Condensate Storage Tank / Sept 1999
T-2 / 210-bbl Condensate Storage Tank / May 2003
T-3 / 400-gallon Methanol Tank 2 / Sept 1999
T-4 / 18,000-gallon Pressurized NGL Storage Tank 2 / 2003
T-5 / 30,000-gallon Pressurized NGL Storage Tank 2 / 2003
T-6 / 300-bbl Emergency tank / Sept. 1999
L1 / Truck Loading / Sept. 1999
L2 / NGL Loading Rack / Mar. 2003
FUG / Process Piping Fugitive Emissions / Sept. 1999

1 w/CC: with catalytic converter.

2 negligible emission.

EMISSIONS

Emissions estimates are based on 8,760 hours per year operation. Emission factors of engines with catalytic converters for NOx, CO and VOC are from manufacturer’s data, tabulated in Table 2. Formaldehyde emission factors for engines are also based on manufacturer’s data with 20% safety factors. Condensate tank emissions are based on EPA “Tanks 4.0.” Flashing losses from condensate tanks was calculated from HYSYS simulation software. The applicant provides the flashing losses results with 20% safety factor. Truck loading emissions are estimated using AP-42 (1/95), Section 5.2. Fugitive emissions are estimated using EPA’s “Protocol for Equipment Leak Emission Estimates” (11/95, EPA-453/R-95-017). The glycol reboiler emissions are based on AP-42 (7/98), Table 1.4-1 and 1.4-2 for commercial boilers. For TEG unit of low pressure gas stream, dehydrator vent emissions are based on GRI-GLYCalc version 4.0 using a recent gas analysis, 3.5 gpm maximum glycol pump rate, a condenser operating at 120 ºF, and 20 MMSCFD gas throughput. For EG unit of high pressure gas stream, dehydrator vent emissions are also based on GRI-GLYCalc version 4.0 using a recent gas analysis, 1.0 gpm maximum glycol pump rate of Milton Roy FR250-144 injection pump, and 8.0 MMSCFD gas throughput.

Table 2 – Emission Factors for Engines

EUs / Engines / NOx
(g/hp-hr) / CO
(g/hp-hr) / VOC
(g/hp-hr) / CH2O
(g/hp-hr)
C1 / White-Superior 8G825 / 2.0 / 2.0 / 1.0 / 0.012
C2 / White-Superior 8G825 / 2.0 / 2.0 / 1.0 / 0.012
C3 / White-Superior 8G825 / 2.0 / 2.0 / 1.0 / 0.012
C4 / Waukesha 7042 GSI / 2.0 / 2.0 / 0.3 / 0.012
C5 / Waukesha L5790 GU / 2.0 / 2.0 / 0.3 / 0.012
C6 / Caterpillar G342 / 2.0 / 2.0 / 1.0 / 0.024

Table 3 - Fugitive Emissions of Gas Stream (Process Piping)

Component
Type / Type of Service / Count / Emission Factors
(lb/hr-component) / %
VOC / Potential Emissions
(lb/hr) / (TPY)
System Valves / Gas / 96 / 0.00992 / 15.90% / -- / 0.66
Flanges / Gas / 130 / 0.00086 / 15.90% / -- / 0.08
Pump Seals / Gas / 2 / 0.0053 / 15.90% / -- / 0.01
Relief Valves / Gas / 24 / 0.01940 / 15.90% / -- / 0.33
Compressor Seals / Gas / 4 / 0.01940 / 15.90% / -- / 0.06
Connectors / Gas / 180 / 0.00044 / 15.90% / -- / 0.06
SUBTOTAL / -- / 1.20

Table 4 - Fugitive Emissions of Condensate/NGL Stream (Process Piping)

Component
Type / Type of Service / Count / Emission Factors
(lb/hr-component) / %
VOC / Potential Emissions /
(lb/hr) / (TPY) /
System Valves / Light Oil / 120 / 0.0055 / 92.41% / -- / 2.67
Flanges / Light Oil / 75 / 0.00024 / 92.41% / -- / 0.07
Pump Seals / Light Oil / 3 / 0.0286 / 92.41% / -- / 0.35
Relief Valves / Light Oil / 10 / 0.0165 / 92.41% / -- / 0.67
Compressor Seals / Light Oil / 2 / 0.0165 / 92.41% / -- / 0.13
Connectors / Light Oil / 150 / 0.00046 / 92.41% / -- / 0.28
SUBTOTAL / -- / 4.17

Table 5 - Facility-Wide Emissions before Modification

ID # / EMISSION UNITS / NOx / CO / VOC
lb/hr / TPY / lb/hr / TPY / lb/hr / TPY
C1 / 800-hp Superior 8G825 Compressor Engine w/CC* / 3.53 / 15.45 / 3.53 / 15.45 / 1.76 / 7.72
C2 / 800-hp Superior 8G825 Compressor Engine w/CC* / 3.53 / 15.45 / 3.53 / 15.45 / 1.76 / 7.72
C3 / 800-hp Superior 8G825 Compressor Engine w/CC* / 3.53 / 15.45 / 3.53 / 15.45 / 1.76 / 7.72
C4 / 1,232-hp Waukesha L7042 GSI Compressor Engine w/CC* / 5.43 / 23.79 / 5.43 / 23.79 / 0.81 / 3.57
C5 / 877-hp Waukesha L5790 GU Compressor Engine w/CC* / 3.87 / 16.94 / 3.87 / 16.94 / 0.58 / 2.54
C6 / 225-hp Caterpillar G342 Compressor Engine w/CC* / 0.99 / 4.35 / 0.99 / 4.35 / 0.50 / 2.17
H1 / 0.225 MMBTUH Reboiler / 0.02 / 0.09 / 0.02 / 0.08 / <0.01 / <0.01
H2 / 0.750 MMBTUH Reboiler / 0.06 / 0.28 / 0.05 / 0.24 / <0.01 / 0.02
V1 / Dehydration Overhead Vent / --- / --- / --- / --- / 0.67 / 3.06
V2 / Dehydration Overhead Vent / --- / --- / --- / --- / 0.26 / 1.14
T1, T2 / (2) 210-bbl Condensate Storage Tanks / --- / --- / --- / --- / --- / 9.46
L1 / Loading Fugitives / --- / --- / --- / --- / --- / 0.50
L2 / Truck Loading, NGL / --- / --- / --- / --- / --- / 17.97
FUG / Process Piping Fugitives / --- / --- / --- / --- / --- / 5.02
Totals / 20.96 / 91.80 / 20.95 / 91.75 / 8.12 / 68.62

* w/CC: with catalytic converter.

Table 6 - Facility-Wide Emissions after Modification

ID # / EMISSION UNITS / NOx / CO / VOC
lb/hr / TPY / lb/hr / TPY / lb/hr / TPY
C1 / 800-hp Superior 8G825 Compressor Engine w/CC* / 3.53 / 15.45 / 3.53 / 15.45 / 1.76 / 7.72
C2 / 800-hp Superior 8G825 Compressor Engine w/CC* / 3.53 / 15.45 / 3.53 / 15.45 / 1.76 / 7.72
C3 / 800-hp Superior 8G825 Compressor Engine w/CC* / 3.53 / 15.45 / 3.53 / 15.45 / 1.76 / 7.72
C4 / 1,232-hp Waukesha L7042 GSI Compressor Engine w/CC* / 5.43 / 23.79 / 5.43 / 23.79 / 0.81 / 3.57
C5 / 877-hp Waukesha L5790 GU Compressor Engine w/CC* / 3.87 / 16.94 / 3.87 / 16.94 / 0.58 / 2.54
C6 / 225-hp Caterpillar G342 Compressor Engine w/CC* / 0.99 / 4.35 / 0.99 / 4.35 / 0.50 / 2.17
H1 / 0.550 MMBTUH Reboiler / 0.05 / 0.22 / 0.04 / 0.19 / 0.01 / 0.01
H2 / 0.750 MMBTUH Reboiler / 0.06 / 0.28 / 0.05 / 0.24 / 0.01 / 0.02
V1 / Dehydration Overhead Vent / --- / --- / --- / --- / 1.28 / 5.59
V2 / Dehydration Overhead Vent / --- / --- / --- / --- / 0.26 / 1.14
T1, T2 / (2) 210-bbl Condensate Storage Tanks ** / --- / --- / --- / --- / --- / 10.39
L1 / Truck Loading, Condensate / --- / --- / --- / --- / --- / 1.12
L2 / Truck Loading, NGL / --- / --- / --- / --- / --- / 6.02
FUG / Process Piping Fugitives / --- / --- / --- / --- / --- / 5.37
Totals / 20.99 / 91.93 / 20.97 / 91.86 / 8.73 / 61.10
Net Change in Emissions / 0.03 / 0.13 / 0.02 / 0.11 / 0.61 / -7.52

* w/CC: with catalytic converter.

** 4.18 TPY flash emission from HYSYS with 20 bbl/day condensate throughput.

Brake-specific fuel consumption for each 800-hp Superior engine is listed at 7,750 BTU/hp-hr at 900 RPM for a fuel consumption of 5,827 SCFH. Air emissions from each engine are discharged through a stack 0.83-foot in diameter, 18 feet above grade, at a rate of 4,461 ACFM at 1,340oF.

Brake-specific fuel consumption for the 1,232-hp Waukesha L7042 GSI engine is listed at 7,581 BTU/hp-hr at 1,000 RPM for a fuel consumption of 9,340 SCFH. Air emissions from engine are discharged through a stack 1-foot in diameter, 18 feet above grade, at a rate of 5,377 ACFM at 1,055oF.

Brake-specific fuel consumption for the 877-hp Waukesha L5790 GU engine is listed at 7,723 BTU/hp-hr at 1,200 RPM for a fuel consumption of 6,773 SCFH. Air emissions from engine are discharged through a stack 0.83-foot in diameter, 18 feet above grade, at a rate of 4,203 ACFM at 1,048oF.

Brake-specific fuel consumption for the 225-hp Caterpillar G342 engine is listed at 7,098 BTU/hp-hr at 1,200 RPM for a fuel consumption of 1,597 SCFH. Air emissions from engine are discharged through a stack 0.67-foot in diameter, 14 feet above grade, at a rate of 851 ACFM at 1,170oF.

The internal combustion engines have emissions of toxic air contaminants, the most significant being formaldehyde, a Category A air toxic with de minimis levels of 0.57 lbs/hr and 0.60 TPY, and a MAAC of 12 µg/m3 (24-hr average). Controlled emissions of formaldehyde were calculated using the manufacturer’s data plus 20% safety factor (0.012 gr/hp-hr for Superior and Waukesha engines, and 0.024 gr/hp-hr for the Caterpillar engine). A HAP oxidation efficiency of 85% was estimated for the 3-way catalytic converter in use on all the engines. Table 7 below lists estimated formaldehyde emissions for the compressor engines. Total formaldehyde emissions are below the de minimis levels.

Table 7 - Formaldehyde Emissions

ID #

/

Sources

/

Formaldehyde

lbs/hr / TPY
C1 / 800-hp Superior 8G825 1,2 / 0.02 / 0.09
C2 / 800-hp Superior 8G825 1,2 / 0.02 / 0.09
C3 / 800-hp Superior 8G825 1,2 / 0.02 / 0.09
C4 / 1,232-hp Waukesha L7042 GSI 1,2 / 0.03 / 0.14
C5 / 877-hp Waukesha L5790 GU 1,2 / 0.02 / 0.10
C6 / 225-hp Caterpillar G342 1,2 / 0.01 / 0.05
Total / 0.12 / 0.56

1 with air-to-fuel ratio controller

2 with catalytic converter

Dehydration units using glycol desiccants will emit benzene, toluene, ethyl benzene, xylenes and n-hexane (BTEX) from the glycol reboiler vapor stack. These compounds are regulated as toxic air contaminants. OAC 252:100-41-40 provides classifications of air toxics; according to these classifications, Benzene is a Category A toxic, while the others are Category C toxics. The applicant performed a gas analysis for the concentration of BTEX for the TEG glycol dehydrator on September 30, 2003 and for the EG glycol dehydrator on October 21, 2003. The emissions were calculated using GLYCalc 4.0 for the concentration of BTEX from the glycol dehydrator, based on (1) for the TEG unit, a maximum gas throughput of 20 MMSCFD, a maximum glycol circulation rate of 3.5 gpm, and above 97% control efficiency of the condenser, and (2) for the EG unit without control, a maximum gas throughput of 8 MMSCFD, a maximum glycol circulation rate of 1 gpm. The following table lists air toxics emissions.