Q487. Under onshore natural gas processing where would you report vent emissions? We have a membrane plant (sweet gas so no acid gas removal) where we remove CO2 and vent. Should this be reported under flare as unlit?

A487. If a membrane unit is used to remove CO2 from natural gas containing concentrations of hydrogen sulfide or carbon dioxide that exceed the concentrations specified for commercially saleable nature gas, then emissions must be calculated and reported as specified in §98.233 (d), as this process meets the definition of acid gas removal unit in §98.238.  Please see EPA-HQ-OAR-2009-0923-1298-18 in the Response To Comments (1719 - 1720) http://www.epa.gov/ghgreporting/documents/pdf/2010/Subpart-W_RTC_part2.pdf for further details on the definitions of sweet and sour gas.