On July 1, 2022, the Oklahoma Department of Environmental Quality (OKDEQ) issued and updated the General Permit for Oil and Gas Facilities (GP-OGF). The GP OGF and required application form (DEQ Form #100-306) was updated to meet current EPA criteria for enforceability and to give more flexibility for permittees.
A copy of the permit, application forms and a Statement of Basis is available on the General Permits webpage.
The permit authorizes construction and/or operation of an oil and gas facility with potential to emit (PTE) emission less than 100 ton/year (tpy) of any regulated air pollutant in an attainment area and less than 10 tpy of any single hazardous air pollutant (HAP) or less than 2 5 tpy of any combination of HAPs.
Facilities eligible for the coverage include:
- New facilities
- Existing facilities currently operating under a minor source air permit.
Ineligible facilities for coverage by the GP-OGF include
- Affected sources requiring a Part 70 (Title V) operating permit
- Certain facilities handling gas containing H2S
- Engines or other combustion units using selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR)
- Facilities located in nonattainment areas
- Facilities requiring specific emissions cap or unit specific limits not covered by the permit.
- Facilities requesting control efficiencies above the level allowed by the permit.
All facilities constructed or operating under the previous GP-OGF are subject to and must comply with this updated GP-OGF within 24-months of July 1, 2022.
To obtain coverage of the new GP-OGF before the end of the 24-month period, operators must submit a Notice of Modification (NOM). At this time, facilities covered by the existing OG-OGF permit will be automatically covered by the new GP-OGF permit on July 1, 2024 – provided the facility meets all permit requirements.
The permitting process for new facilities requires submission of separate, completed Notice of Intent (NOI) to Construct and NOI to Operate forms.
A NOM can also be used to add emission sources or changes to emissions for the facility.
Flares and Enclosed Combustion Devices
Requirements for flares and enclosed combustion devices (ECD) include:
- Default vapor control efficiency of equal to or less than 98%. Facility must obtain an individual air permit to use a control efficiency greater than 98%.
- Flares must meet 40 CFR §60.18 requirements for minimum heating value and maximum flare tip velocities.
- Operate with a flame present at all times by having a continuous pilot flame or an automatic ignition system.
- Monitor presence of a pilot flame using thermocouple or equivalent device to detect the presence of a flame.
- Maintain records of the pilot flame not operating.
To ensure the facility using the GP-OGF has federally enforceable limits (and so avoids NSPS OOOOa controls) for the storage tanks, the permit requires the following listed below.
The permit requires that individual storage tanks (produced water, crude oil and condensate) limit VOC emission to 5.9 tons/year based on a 12-month running total.
The permit incorporates NSPS OOOOa requirements for averaging facility-wide throughputs across tanks at a facility (after November 16, 2020). This requires:
- Tanks must be manifolded with piping so that all vapors are shared among the tanks’ headspaces.
- Use a closed vent system designed, operated and maintained to route vapors to process or a control device.
- Control device must control VOCs by at least 95%.
Tank emission calculations must account for breathing, working and flash gas losses based on ODKEQ guidance documents.
Also, the permit sets the maximum capture efficiency for a control device at 98%. Below is an example of how to apply a capture efficiency with the emission controls using a fare.
Uncontrolled: 100 tpy VOC
Capture efficiency for vapors: 98%
Flare control efficiency: 95%
Combustion emissions: (100 tpy VOC)(0.98)((1-0.95) = 4.9 tpy VOC
Vented emissions: (100 tpy VOC)(1-0.98) = 2 tpy VOC
Total Emissions = 4.9 tpy + 2 tpy = 6.9 tpy
Options for controlling storage tanks include enclosed combustion devices (ECD) and flares.
Vapor Recovery Systems
The permit does not put an efficiency limit on vapor recovery units (VRU) that recover storage tank vapors and sends the natural gas back to the system or a pipeline. The OKDEQ treats VRUs as process equipment if it sends the gas back to the system or pipeline. Even though VRUs are treated as process equipment, a permittee is required to calculate storage tank emissions based on a collection efficiency equal to or less than 98% for VRU systems.
Cimarron has unparallel expertise in vapor capture for storage tanks using VRUs. Our models can handle flowrates less than 50 MSCFD to over 1500 MSCFD. Using a VRU avoids emissions associated with venting to the atmosphere and flaring natural gas.
Glycol Dehydration Units
To calculate glycol dehydration unit emissions, the permit lists GRI-GLYCalc Ver. 4.0 or later, a process simulator or the Atmospheric Rich/Lean (ARL) Method to calculate emissions for VOCs and hazardous air pollutants (HAPs). NOTE: The ARL method does not estimate methane emissions and is not suitable for glycol dehydration units without a flash separator and not suitable if stripping gas is used.
Allowable control efficiencies for glycol dehydration units include:
- Condenser plus combustion in enclosed combustion device (ECD): <=95% (if meet (90% for condenser and have igniter/pilot for ECD)
- Condenser maximum allowed control efficiency: <=90% for VOCs and HAPs.
- Vapor recovery/recycled/recompressed and sent to system or pipeline: <=100% for VOCs and HAPs.
- Route still column vapors to reboiler or heater burner: <=50%.
- Route still column vapor to reboiler/burner flame zone/firebox when firing and delivered to an in-stack igniter when firebox not burning: <=95%.
- Condenser plus combustion in reboiler/heater firebox: <=95% (if meet (90% for condenser)
New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAPS)
The permit includes, by reference, applicable oil and gas facility New Source Performance Standards (NSPS). These include NSPS K, Ka, Kb, GG, IIII, JJJJ, KKK, LLL, OOOO, OOOOa.
Also, applicable National Emission Standards for Hazardous Air Pollutants (NESHAPS) are included by reference include HH, HHH, ZZZZ
Internal Combustion Engines
The current OG-GPF requires OKDEQ testing of all engines. The following are current testing requirements.
- Engines greater than 250 horsepower (hp) must conduct an initial performance test within 180 days of beginning operation. This applies to uncontrolled and controlled engines.
- Controlled engines greater than 250 horsepower (hp) must conduct semiannual performance test using EPA methods or using a test that meets the OKDEQ’s “Portable Analyzer Guidance.”
- Emergency use engines and engines that are less than or equal to 250 hp are exempt from OKDEQ State stack testing requirements.
Engines that have stack testing and emission limitations according to NSPS JJJJ and IIII and NESHAPS ZZZZ must still comply with these regulations.
Four-stroke, rich-burn (4SRB) engines using nonselective catalytic reduction (NSCR) catalyst must be equipped with an Air to Fuel Ratio Controller (AFRC). The ARFC oxygen sensor must be replaced every 2200 operating hours or less.
The previous GP-OGF required uncontrolled engines at a true minor source and controlled engines to be periodically tested on a quarterly basis.
Operators can submit a NOM to obtain coverage under the new OP-GPF permit and use the new emission testing requirements.
Maintenance, Startup and Shutdown (MSS)
The general permit requires the permittee to estimate VOC emissions from any MSS activity and include those emissions in calculating compliance with the facility-wide emissions cap for VOC. Some MSS emissions, such as blowdowns, can be estimated using mass balance equations, volume of gas vented, the number of events, and percent VOC.
Many operators choose to operate backup and redundant emission controls to handle MSS. This includes use a VRU to control storage tank vapors and an ECD to control storage tank vapors if the VRU is out of service. Also, a low pressure ECD may be used for routine controls (storage tanks, dehydration units) and a high pressure ECD to control facility or pipeline blowdown emissions.
Summary and Conclusions
The new GP-OGF air permit applies to oil and gas production facilities. Facilities must comply with the new permit by July 1, 2024. Existing facilities covered by the “old” GP-OGF can submit a Notice of Modification (NOM) to obtain coverage prior to July 1, 2024. New oil and facilities that meet requirements of the GP-OGF should submit a complete Notice of Intent to Construct application form.
The new GP-OGF includes:
- Specific limitation on emission control efficiencies.
- Requirements for averaging emissions for storage tanks and calculating tank emissions on a rolling 12-month total.
- Required emission control capture efficiencies.
- Stack testing that is required less frequently.
- Maintenance, Startup and Shutdown (MSS) VOC estimates are required.
Cimarron solutions to assist with compliance with the new flaring and venting rules include:
- Retrofit flares and enclosed combustors with automatic igniters, pilot systems and alarm systems for flare pilot/ignitor malfunction.
- Automated alarm system technology (SyteLink360TM)
- Installation of vent and flare gas meters
- Measurement of vent gas from storage tanks using our IQR Teams.
- Fugitive leak detection and repair monitoring
- Vapor recovery units (VRU)
- Vapor recovery towers (VRT)
- Flares and enclosed combustors
Cimarron – Who We Are
Cimarron’s overall goal is to reduce greenhouse gas emissions for all industries as we work with our clients to create a cleaner environment.
The company engineers and manufactures environmental, production and process equipment for the upstream, midstream and downstream energy industries, as well as environmental control solutions for biogas at wastewater facilities, digester tanks and landfills.
Cimarron offers our customers the know-how and environmental expertise to meet the environmental standards of today and tomorrow. Cimarron is committed to bring value to the Energy industry and their shareholders based on our financial strength, experienced personnel, and engineering capabilities.
As a company, we thrive every day to make a difference through innovation (e.g. ESG), customer focus, and operational efficiency. In addition to being present in all major regions in the US, Cimarron serves more than 45 countries around the world, ranging from offshore to desert. From key operational centers in the United States, Italy and the United Arab Emirates, Cimarron offers ongoing service and support through its own field service personnel and strategic third-party partners, creating a cleaner environment for our customers and their shareholders.
Since its founding in the mid-1970’s in Oklahoma, the company’s product offering has expanded from production equipment to include the largest line of environmental solutions that capture or incinerate fugitive vapors. With the acquisitions of HY-BON/EDI in 2019 and AEREON (including Jordan Technologies) in 2020, Cimarron has added strong brands, products, and services to its portfolio.