Current Situation:
Infrequent spot checking with steel cylinders (commonly referred to as “bombs”), poor sampling methods, inaccurate and imprecise lab analysis, and a general lack of data, has created the impression that North American natural gas is “mercury free.”
However, volcanoes produce mercury and weathering of volcanic rocks contaminate oil and gas reservoirs with mercury. North America has been volcanically active throughout Earth’s history, and there exists no recognized geological or biological process that would preferentially remove mercury from only one continent.
Ohio Lumex collected samples of raw natural gas from drill sites in the Permian Basin of Texas using sorbent traps. We analyzed the sorbent traps in our NELAP accredited laboratory with a Zeeman Atomic Absorption Spectrometer. We measured mercury levels up to 2000 nanograms/m3 (0.240 ppbv). Mercury is present at significant concentrations in Permian Basin natural gas reservoirs.
Why Upstream Gas Producers Should Care:
- Mercury corrodes brazed aluminum heat exchangers used in the liquefaction process. Manufacturers recommend limiting the mercury concentration to < 100 nanograms/m3 (0.012 ppbv).
- Mercury contaminates heavier fractions (ethane C2 and propane C3) in natural gas fractionalization plants.
Recommended Action:
Test to confirm concentrations associated with the spatial and temporal variability of mercury in natural gas reservoirs. Current industry standards recommend complete removal of mercury for aluminum heat exchangers to the lowest routinely detectable level, to ensure adequate equipment performance and protection.
Solution if Mercury is Found:
- Install Mercury Removal Unit (MRU) from a reliable provider, including CLS Industrial Purification and Axens.
- Install On-Line Ohio Lumex Mercury Analyzer (AMNG-EXP) to continuously monitor input or output of the MRU.
Ohio Lumex is the worldwide leader in mercury measurement and analysis.
