In-line Catalytic Purification of Carbon Dioxide Used in Precision Cleaning Applications

The use of carbon dioxide (CO2) in precision cleaning applications requires a high-purity feed stream of CO2, which can add considerable cost to the overall process. The ability to purchase and clean a lower grade of CO2 would represent a significant cost savings. In this study, an in-line catalytic purification system was employed to clean two low-purity grades of CO2 to very low contaminant levels at flow rates relevant for full-scale precision cleaning applications (3.63 kg/h or 8 lb/h). A “food” grade of CO2 had an unpurified contaminant concentration of 4.0 ng/g, and a “bone dry” grade had an unpurified contaminant concentration of 4.9 ng/g. After catalytic purification, the food grade contaminant concentration was reduced to 0.14 ng/g (a 97% reduction), and the bone dry grade contaminant concentration was reduced to 0.26 ng/g (a 95% reduction).