Nelson, Jr., David D.

DOE OSTI2018

Methods and apparatus for measuring small leaks from carbon dioxide sequestration facilities

In one embodiment, a CO.sub.2 leak detection instrument detects leaks from a site (e.g., a CO.sub.2 sequestration facility) using rapid concentration measurements of CO.sub.2, O.sub.2 and optionally water concentration that are achieved, for example, using laser spectroscopy (e.g. direct absorption laser spectroscopy). Water vapor in the sample gas may not be removed, or only partially removed. The sample gas may be collected using a multiplexed inlet assembly from a plurality of locations. CO.sub.2 and O.sub.2 concentrations may be corrected based on the water concentration. A resulting dataset of the CO.sub.2 and O.sub.2 concentrations is analyzed over time intervals to detect any changes in CO.sub.2 concentration that are not anti-correlated with O.sub.2 concentration, and to identify a potential CO.sub.2 leak in response thereto. The analysis may include determining eddy covariance flux measurements of sub-surface potential carbon.

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DOE OSTI2016

Techniques for active passivation

In one embodiment, active (continuous or intermittent) passivation may be employed to prevent interaction of sticky molecules with interfaces inside of an instrument (e.g., an infrared absorption spectrometer) and thereby improve response time. A passivation species may be continuously or intermittently applied to an inlet of the instrument while a sample gas stream is being applied. The passivation species may have a highly polar functional group that strongly binds to either water or polar groups of the interfaces, and once bound presents a non-polar group to the gas phase in order to prevent further binding of polar molecules. The instrument may be actively used to detect the sticky molecules while the passivation species is being applied.

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