In the oil and gas industry, greenhouse gases (GHGs) and volatile organic compounds (VOCs) are inevitably released into the environment during operations and maintenance despite best efforts. However, the impact can be minimized using a wide variety of emissions control technologies and techniques. For example, leak detection and repair equipment are employed to ensure “fugitive” emissions from valves, seals, and other connections can be monitored and corrected.
Recovery and combustion systems make up another important part of emissions control systems. At wellheads, pressure and volume controls may require the venting or flaring of hydrocarbon vapors. Storage tanks for hydrocarbon liquids may emit pollutants during operations due to material flow and daytime heating. Pneumatic pumps and controllers throughout natural gas processing systems may eventually vent gases. In most cases, vapor recovery or combustion systems can be built inline to add some measure of control over emissions. Additionally, low- or no-bleed pneumatic controllers can be installed to further reduce emissions at lines and pumps.
Gas pipelines are another source of emissions, particularly during testing and in-line inspections involving a technique called pipeline blowdown. Pipeline blowdown is used to reduce or vent off gas pressure in the pipeline. Some companies and organizations are developing alternative testing and inspection tools that don’t require blowdowns, reducing methane pollution. Alternatives to venting during inspection and service include temporarily rerouting or incinerating the gas or capturing and using the gas to fuel nearby work equipment.
In some cases the technology and techniques of emissions control in refineries and other industry facilities are driven by changing regulations. In May 2014, the U.S. Environmental Protection Agency (EPA) announced emissions requirements on refineries will be tightened, particularly those along “fenceline communities.” The changes are forcing U.S. operators to upgrade emissions control systems to monitor additional chemicals like benzene and modernize other such systems in storage tanks and certain oil heating units. Other research in 2014 suggests additional methane pollution controls will also eventually be required, especially in shale drilling areas.