System and method for impurity detection in beverage grade gases
A system and method for determining impurities in a beverage grade gas such as CO 2 or N 2 relies on a coupling of FTIR analysis and UV fluorescence detection. Conversion of reduced sulphur present in some impurities to SO 2 can be conducted using a furnace. In some cases, CO 2 % also is determined.
1. A system for measuring impurities in a beverage grade gas, the system comprising:
a spectrometer including a gas cell for detecting an absorbance spectrum of the gas in the gas cell, wherein the gas cell is configured for pressures higher than two atmospheres; and
a sulfur analyzer including an oxidizing furnace for converting reduced sulfur present in the gas to SO 2 and a UV fluorescence apparatus for determining total SO 2 amounts in the sample.
2. The system of claim 1 , wherein the gas cell is a multiple path type cell.
3. The system of claim 1 , further comprising a computer for collecting, analyzing and/or reporting data from the spectrometer and the sulfur analyzer.
4. The system of claim 1 , further comprising software for collecting, analyzing and/or reporting data.
5. The system of claim 1 , further comprising calibration information for pure CO 2 and/or one or more impurity for the spectrometer.
6. The system of claim 1 , wherein the spectrometer is provided with a mercury cadmium telluride detector.
7. A method for analyzing a beverage grade gas, the method comprising:
directing a first portion of a gas sample to a gas cell;
measuring impurities present in the gas cell with a spectrometer at pressures higher than two atmospheres;
directing a second portion of the gas sample to an oxidizing furnace;
converting reduced sulfur present in the second portion to SO 2 ; and
measuring a total SO 2 in the second portion of the gas sample.
8. The method of claim 7 , wherein the total SO 2 is the sum of SO 2 initially present in the second portion of the gas sample and SO 2 converted from reduced sulfur.
9. The method of claim 7 , wherein total SO 2 measured in the second portion of the gas is compared with SO 2 measured by spectrometer in the first portion of the gas sample to determine a TRS amount.
10. The method of claim 7 , wherein data obtained for impurities in the first portion of the gas sample are compared with calibration data.
11. The method of claim 7 , wherein a CO 2 % in the first portion of the gas sample is determined by spectrometer and compared to calibration information.
12. The method of claim 7 , wherein the impurities are selected from the group consisting of SO 2 , total sulfur, NH 3 , CO, NO, NO 2 , H 2 O, HCN, CS 2 , hydrogen cyanide hydrogen cyanide, methanol, moisture, acetaldehyde, methane, total hydrocarbons, benzene and total aromatic hydrocarbons.
13. The method of claim 7 , wherein the gas sample is obtained from a location in a plant.
14. The method of claim 7 , wherein the beverage grade gas is CO 2 or N 2 .
15. The method of claim 7 , wherein total SO 2 is measured by UV fluorescence or by FTIR spectrometry.
16. A system for measuring impurities in a beverage grade gas, the system comprising:
a spectrometer, wherein a gas cell of the spectrometer is configured for pressures higher than two atmospheres;
an oxidizing furnace for converting reduced sulfur present in a sample to SO 2 ; and a manifold for directing the SO 2 from the oxidizing furnace to the spectrometer.
17. The system of claim 16 , wherein the spectrometer includes a gas cell.
18. The system of claim 17 , wherein the gas cell is a multiple pass type cell.
19. The system of claim 17 , wherein the gas cell is a flow through gas cell.
20. The system of claim 1 , wherein the gas cell is constructed from welded stainless steel.