New Technology Reduces Carbon Emissions from Natural Gas Compression and Production Facilities

Abstract Natural gas compression contributes significantly to greenhouse gas (GHG) emissions, emitting nearly 10% of the total carbon dioxide equivalent per year from the Oil & Gas industry sub-sector1. The most common method of reducing GHG emissions from compression currently involves converting to electric drive2. Electric drive is not a preferred fuel source with most compressor operators because it can be expensive, difficult to acquire at field sites, and it can place new demands on existing power supply grids. A new chemical-free process has been developed with a small footprint to capture exhaust from natural gas drive compressors and supporting gas-fueled production equipment. The process separates carbon dioxide (CO2) and nitrogen from exhaust allowing the CO2 to be discharged at high pressure for transport, sequestration, or enhanced oil recovery (EOR). GHG emissions are significantly lowered from compression while permitting operators to maintain their preferred natural gas fuel source. The patented process3 treats high volumes of exhaust, up to 70 million scf/D, containing CO2, nitrogen, and water. It incorporates innovative technology for carbon capture including a unique rotary separator design to remove water and centrifugally separate CO2 from exhaust gas. Advanced moving wall compressors and moving wall expanders have been developed to regulate system pressures and temperatures to values necessary for separation and discharge of supercritical CO2. The system is mounted on a small skid allowing for easy placement at typical production and midstream sites. Technical and economic results of the system are presented, demonstrating that high-quality carbon dioxide is captured, separated, and pressurized for disposal or commercial use without the use of large equipment. This paper presents details of the process with initial test results and how it can be used on thousands of oil and gas production, midstream, and transmission sites. The exhaust gas stream is processed after lowering the temperature, then water is removed, and CO2 is separated from nitrogen without chemicals. The design lowers GHG emissions from all internal combustion engines, turbines. and supporting production equipment. The CO2 produced from this technology can be greater than 99% pure and meets IRS guidelines using 45Q tax credits for carbon sequestration.4 The oil and gas industry has a long history removing CO2 from gas streams.5 The novel technology presented incorporates new and practical solutions for oil and gas operators to reduce their GHG Scope 1 and Scope 2 emissions while maintaining their preferred natural gas fuel source at their midstream, transport, and production sites.