Augmented raman analysis using absolute raman
AssigneeEndress+Hauser Optical Analysis, Inc.
InventorsJoseph B. Slater, Marc Winter, Oliver Link
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Abstract
A method for determining an amount of a Raman-invisible gas in a multi-component gas stream includes performing a first and second absolute Raman analysis on the gas stream. A decrease in the absolute Raman bands from the first analysis to the second analysis is attributed to an increase of the Raman-invisible gas in the gas stream. The amount of the Raman-invisible gas is calculated from the difference between the first and second sets of Raman bands. The calculation of the Raman-invisible gas is verified via a measurement and a calculation of a secondary property of the gas stream such as the thermal conductivity of the gas stream or the density of the gas stream.
Claims6
A method for determining an amount of a Raman-invisible gas in a sample gas stream, the method comprising:
- providing a Raman spectroscopic device, including a Raman laser;
- performing a Raman analysis of a calibration gas stream, wherein the Raman analysis of the calibration gas stream includes measuring a pressure and a temperature of the calibration gas stream;
- determining a first set of absolute Raman bands from the Raman analysis of the calibration gas stream, wherein the first set of absolute Raman bands correlate to Raman-visible gases within the calibration gas steam;
- calculating, using the first set of absolute Raman bands, first amounts of each Raman-visible gas present in the calibration gas stream;
- waiting a first time period;
- performing a Raman analysis of the sample gas stream, wherein the Raman analysis of the sample gas stream includes measuring a pressure and a temperature of the sample gas stream;
- determining a second set of absolute Raman bands from the Raman analysis of the sample gas stream, wherein the second set of absolute Raman bands correlate to the Raman-visible gases within the sample gas stream;
- calculating, using the second set of absolute Raman bands, second amounts of each Raman-visible gas present in the sample gas stream;
- comparing the amount of each Raman-visible gas in the sample gas stream to the respective amount of each Raman-visible gas in the calibration gas stream;
- attributing decreases in the amounts of the Raman-visible gases in the sample gas stream to a displacement of the Raman-visible gases in the sample gas stream by a Raman-invisible gas in the sample gas stream;
- and
- calculating the amount of the Raman-invisible gas in the sample gas stream using the decreases in the amounts of the Raman-visible gases in the sample gas stream.
Dependencies are inferred from the claim text.