Proper Sampling and Analysis of CO2 Pressurized Gas Tanks for Contamination Testing

When handling pressurized CO2 gas tanks, proper sampling and testing procedures are critical to ensure the quality and safety of the CO2. This article will guide you through the process of taking a sample from a CO2 pressurized gas tank and what tests you might request from a lab to test for contamination. We will also cover an alternative, less expensive method for sampling.

Procedures for Sampling CO2 Pressurized Gas Tanks

To take a sample from a CO2 pressurized gas tank for the purpose of contamination testing, you will need the following equipment:

Tubing A clean tray A clean sample bottle Type 1 demineralized water

Less Expensive Sampling Method:

Fill the clean tray with water and the sample bottle with Type 1 water to the top. Invert the bottle while it is in the tray to ensure there is no air in it. Connect the CO2 tank to the tubing and begin purging the tubing of air by opening the CO2 tank valve a little. While it is purging, place the open end of the tubing in the tray full of water and continue to purge the tube of air. Submerge the tubing in the bottle filled with water and allow the CO2 to enter the bottle, displacing the water. Remove the hose from the bottle now filled only with CO2 and cap the bottle with an airtight stopper while still underwater. After sealing the bottle tightly, you can remove it from the water. The lab will be able to get the CO2 out even at atmospheric pressure.

Alternative Sampling Method:

Gas Regulator Double Stopcock Sampling Tube Pressure Tube Vacuum Pump Fit the gas regulator on the pressurized CO2. Connect the pressure tube one end to the vacuum pump and the other end to the sampling tube. Open one end of the stopcock to release the CO2 gas into the sampling tube and note the pressure at which it is measured. Close the stopcock and detach the sampling tube, then send it to the laboratory for analysis. If the analytical lab offers a service component, they will handle the sampling for you. Simply hire them and request a package service for gas analysis.

Testing for Contamination

The choice of contaminants to test for will depend on the intended use of the CO2 and the possible sources of contamination. For instance, if the CO2 is to be used for making dry ice for general freezing, the acceptable levels of contamination are much higher than those required for carbonating beverages or other forms of human consumption. You can determine the contaminants to test for based on customer requirements or industry standards.

Included Tests:

Gas Chromatography: A common test used for detecting specific contaminants in CO2. This technique can detect impurities in trace amounts, ensuring the CO2 meets the required standards. Mass Spectrometry: This method is highly sensitive and can identify and quantify even the smallest amounts of contaminants. It is particularly useful for detecting trace contaminants.

If you know the volume and pressure required for the sample, locate a suitable clean pressure vessel with the appropriate pressure rating. Install a throttling valve and a pressure gauge, ensuring a fitting suitable for the sample bottle. Pull a good vacuum, fill the vessel with gas, and vent it to the atmosphere several times to remove any remaining contaminants. Finally, fill the vessel to the requested pressure and close the sample bottle valve. Package the vessel well and deliver it to the lab for analysis.

Conclusion

Proper sampling and testing of CO2 pressurized gas tanks are crucial for ensuring the purity and safety of the CO2. Whether you use a lesser-cost method or a more advanced setup, the goal remains the same: to detect and eliminate any contaminants that could affect the CO2's intended use. By following the procedures outlined in this article, you can ensure that your CO2 is of the highest quality and meets all relevant safety and quality standards.