The EPA requires facilities emitting 25,000 metric tons of CO2e annually to report annual GHG emissions per EPA mandate 40 CFR Part 98. Subpart W pertains to all aspects of the natural gas industry, including offshore production, onshore production, onshore gas processing, transmission, underground storage, liquefied natural gas (LNG) storage, LNG import and export, and natural gas distribution.
Several applications range from high flows for the blown-down vent stack to the very low flow rates found in compressor seal leakage. Many of the emission sources are venting and fugitive emissions. The EPA estimates that fugitive and vented greenhouse gas emissions in petroleum and natural gas facilities are the second-largest source of human-made methane emissions in the United States. While some GHG sources can be estimated or modeled, many different sources make calculating GHG emissions very complex. Over the long term, direct measurement of the GHG emissions will be more straightforward, requiring much less time and workforce than performing all the necessary calculations. Also, obtaining an exact measurement of the natural gas leakage loss will provide the operator with valuable information to increase their performance.
SAGE thermal flow meters are ideally suited for directly measuring GHG emissions. The very low flow rates in small pipe sizes can easily be measured using SAGE’s flow body designs, ranging from ¼ inch to four inches. The higher flows in the larger pipe sizes can easily be handled with the insertion probe. The high turndown capabilities and the excellent resolution provide the most accurate flow measurements over a broad range of flow rates. Particularly important is the in-situ calibration verification, which permits the user to verify that the meter is operating correctly. The ability to perform this test without removing the pipe’s flow meter is of the utmost importance to the user.
With the EPA now requiring emitters to report annual GHG emissions, flow meters are being scrutinized to find the best ways to measure and report data. Mass flow meters are becoming the preferred choice to monitor and measure GHG emissions. One of the primary advantages of thermal mass flow meters (over volumetric meters) is that the meter measures mass flow. The SAGE products are state-of-the-art, as Sage was the first to market a digitally-driven sensor, a graphic display, and onsite calibration verification. The SAGE meter is the only TMFM that provides a convenient, in-situ, and in-line calibration check that assures the flow meter retains the original NIST traceable calibration and is accurate.