The upstream oil and gas sector faces new and more demanding, Environmental Protection Agency (EPA) regulations due to growing greenhouse gas (GHG) concerns. Regulations governing many areas of oil and gas industry require GHG emissions reduction and reporting. The statutes often require the use of vapor recovery units or combustion devices (flares).
40 CFR Part 98, Subpart W – Oil and Gas Systems
The EPA requires GHG reporting of emissions to the atmosphere from flares and vents from onshore and offshore petroleum and natural gas producers. Each flare must report carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) emissions and each vent must report CO2 and CH4 emissions. One method of determining these emissions is the simple use of a continuous flow meter in the line going to the vent or flare.
CFR 40 Part 60 Subpart OOOO – Stationary Sources
The Clean Air Act authorizes the EPA to develop technology-based standards for specific categories of stationary sources. These are New Source Performance Standards (NSPS) and are in 40 CFR Part 60. CFR 40 Part 60 Subpart OOOO are performance standards for stationary sources that are new, reconstructed or modified after August 23, 2011, for crude oil and natural gas production, transmission and distribution facilities. This section requires reduction of GHG emissions at wells, storage tanks, and compressor stations through the use of a vapor recovery system (VRU) or a combustion control device (flare). One method to ensure that the flow rate to the VRU or flare is within the manufacturer’s operating range is by measuring the gas flow with a thermal mass flow meter.
More information is available in Sage Metering’s white paper, “Flare Gas and 40 CFR 60 Quad O: Storage Vessels Deadline.”
There are multiple applications in a gas compressor station where thermal mass flow meters can be utilized. These include measuring the flow to the engine, flow rate from dry seals and during blowdown. Compressor station applications are covered in detail in our Sage Application Brief, Natural Gas Compressor Station Flow Control
Thermal Mass Flow Meters
In these situations a thermal mass flow meter will meet the requirements and have the following benefits:
- Direct mass flow measurement without need for pressure and temperature correction
- Insertion probe simplifies installation
- High rangeability with ability to detect flows at very low velocities
- Factory calibrated – no need for field calibration
- Includes a simple method to verify the meter is within calibration