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Carbon Dioxide Cleaning Process

Dry ice blast cleaning is a process in which particles of solid carbon dioxide, commonly known as dry ice, are propelled at high velocity to impact and clean a surface. Upon impact, the CO2 particles return to their natural state as carbon dioxide gas, thus disappearing as they clean. Although it is often compared to sand blasting, bead blasting, or soda blasting, dry ice actually clean differently. Traditional abrasive blasting methods clean through a chiseling action, much like using an ice pick, but often take away part of the substrate as well. Dry ice, on the other hand, might better be compared to a spatula as it lifts away the contaminant without damaging the targeted surface.

Step #1

Energy Transfer - With dry ice blasting, dry ice pellets are propelled out of the blasting gun at supersonic speed and impact the surface. The energy transfer knocks off the contaminant without abrasion. The force of this impact is the primary means of cleaning.

Step #2

Micro-Thermal Shock - The cold temperature during dry ice blasting of the dry ice pellets hitting the contaminant creates a micro-thermal shock (caused by the dry ice temperature of -79º C) between the surface contaminant and the substrate. Cracking and delaminating of the contaminant occurs furthering the elimination process.

Step #3

Gas Pressure - The final phase of dry ice blasting has the dry ice pellet explode on impact, and as the pellet warms it converts to a harmless CO2 gas which expands rapidly underneath the contaminant surface. This forces off the contaminant from behind. The contaminant is then relocated, typically falling to the ground. Since the dry ice evaporates, only the contaminant is left for disposal.

Benefits of CO₂ Cleaning

• Superior clean: fewer cleaning cycles means less downtime
• Machines can be cleaned in place: dry ice blasting is a dry process and requires no disassemble/reassembly which means much less downtime
• Quicker clean: Less resources, more runtime, and lower cost
• Non-abrasive, nonflammable, and non-conductive: dry ice blasting won't damage most substrates and can be used safely on electrical components
• No secondary waste clean-up: this not only saves additional clean-up labor and expense, but also means temporary containment areas could possibly be reused.
• Can get into tight spaces other methods can not
• Environmentally friendly: meets USDA, FDA and EPA guidelines
• Operator safety: no exposure to chemicals or grit media
• Operator efficiency: not as labor intensive as traditional cleaning methods
• Clean enough for the food industry, strong enough for everything else

Safety Notes

1. Environmental emissions
2. Cryogenic exposure Nozzle stream and CO₂ pellets are extremely cold @-80C. Direct contact with skin will result in superficial “cold” burns
3. Carbon dioxide exposure and oxygen replacement
4. Normal breathing air contains approximately 0.03 % CO2 Building codes require air exchanges/sensors when CO₂ level exceed 1000ppm (normal is 350ppm) Concentration of CO₂ should be maintained below 0.1%.  

Related

• Flushing & Vacuum Process
• Hydrolasing Cleaning Process