Dry ice blasting (sometimes referred to as CO2 blasting) is a relatively recent cleaning method that use solid CO2 pellets. It is largely employed in a range of industrial applications. The pellets sublimate (change from a solid blast pellet to a vapour (CO2)) and leave no residue. For a variety of reasons, the procedure is preferable to sandblasting, glass bead blasting, and other forms of cleaning processes.
Dry ice cleaning is increasingly becoming the preferred technique of cleaning, both for environmental and production reasons. Industry has had to reduce waste as a result of stringent environmental restrictions. Furthermore, many people are becoming more aware of the worldwide environmental effect of their manufacturing methods. However, the huge performance increases from dry ice blasting amplify these advantages: little or no production downtime, high-quality clean, and little equipment damage.
What Is Dry Ice and How Does It Work?
Dry ice pellets are manufactured by expanding liquid carbon dioxide (CO2) at ambient pressure to make snow from a pressurised storage tank. The snow is then compacted into hard pellets using a die.
Dry ice (CO2) particles are driven to supersonic speeds and strike and clean a surface during the dry ice blasting process. Compressed air accelerates the particles, exactly like other blasting methods. Dry ice blasting may be broken down into three phases.
Energy Transfer is the first step.
Dry ice pellets are launched at supersonic speeds from the blasting gun and contact the surface. The pollutant is knocked off without abrasion by the energy transfer. The major way of cleansing is the power of the hit.
Micro-Thermal Shock is the second step.
The cold temperature of the dry ice pellets striking the contamination causes a micro-thermal shock between the surface contaminant and the substrate (induced by the dry ice temperature of -109F). The contaminant cracks and delaminates, speeding up the removal process.
The next step is to check the gas pressure.
The dry ice particle explodes on impact in the last step, and as it heats, it transforms to a harmless CO2 gas that expands rapidly beneath the contaminated surface. This pushes the contaminant backwards. After that, the pollutant is moved, usually to the ground. Only the contamination remains once the dry ice has evaporated.
Specifications of Operation
A few considerations must be considered while using dry ice blast cleaning equipment. Though dry ice is highly safe to use, basic safety precautions must be observed, such as wearing hand, eye, and ear protection. First and foremost, the procedure is noisy, and hearing protection should be used. Second, dry ice has a temperature of -109 degrees Fahrenheit. When dealing with it, gloves should always be used. Third, a mask is advised for eye and nose protection in dusty locations. Otherwise, regular eye and ear protection, as with sand blasting or pressure cleaning, would suffice. Fourth, the gun should never be directed at another person, since this might result in significant damage.
Blasting in a confined space is also safe if sufficient ventilation is used. Because CO2 is 40 percent heavier than air, exhaust fans must be placed at or near ground level when blasting in a confined space. Existing ventilation in an open shop setting is sufficient to avoid excessive CO2 accumulation.
Furthermore, while many applications using this type of equipment only require 80 to 100 psi and 120 to 150 CFM, a study of your system air would be required to evaluate if your facility has the requisite capacity to run the equipment at the levels required for your applications.
Dry Ice Blasting vs. Conventional Methods
Consider the following for a quick comparison of dry ice cleaning to other standard cleaning methods:
Dry ice blasting does not produce trash, is non-abrasive, non-toxic, and non-electrically conductive.
- Sandblasting, glass beads, and corn cob are abrasive and create a large amount of debris for disposal.
- Pressure washing is conductive to electricity.
- Solvents pollute the environment, are poisonous, and may conduct electricity.
The Advantages of Dry Ice Blasting
The advantages of CO2 blasting may be divided into six categories. Following each benefit, the following points are discussed:
The first benefit is that cleaning in-place reduces downtime.
Typical cleaning techniques need disassembling equipment and transporting it to a designated place for cleaning. With dry ice blasting, this is not the case. In most cases, equipment may be cleaned on-site and while hot. As a result, numerous time-consuming and labor-intensive procedures that were previously necessary with conventional technologies like sand blasting may be removed, including:
- Take a break
- Equipment transportation to and from a designated cleaning area
- Disassembly and re-assembly
- Time to reheat
- Dry ice blasting may cut cleaning time in half, from days to hours.
Benefit #2 – More thorough and faster cleaning
When compared to scrubbing with abrasive pads or wire brushes, dry ice blasting provides a superior cleaning while saving time. It is possible to save a lot of money on labour. Furthermore, the CO2 blasting process cleans nooks that are difficult to reach by hand. As a consequence, equipment operates more effectively, and possible leaks are identified, potentially avoiding significant system breakdowns.
Elimination of Equipment Damage (Benefit #3)
Sandblasting, for example, has an aggressive and abrasive impact on the surface. They can actually remove a portion of the surface, drastically altering the surface structure. Dry ice is non-abrasive and does not alter the structure of a surface. It removes the impurities. Second, because equipment can now be cleaned in place, there is no risk of harm from transporting it to and from a specific cleaning location.
Benefit #4 – Solvent Reduction or Elimination
When employing CO2 pellets, no solvents are utilised. Certain businesses may require this in order to comply with environmental rules or increase worker safety. There are no concerns about toxicity.
Reductions in Waste Disposal (Benefit #5)
Other cleaning processes, such as solvents, sand blasting, or other ways, turn the cleaning agent into a secondary contamination that must be disposed of with the initial contaminate as hazardous waste. The only waste generated by dry ice blasting is the contamination itself, because the CO2 pellet vaporises upon contact. By alone, this can lead to considerable waste reduction.
Increased Safety (Benefit #6)
CO2 blasting pellets are non-toxic and non-hazardous, which benefits the environment, your personnel, and your manufacturing facility:
- There is no secondary waste.
- Environmentally friendly
- Employees are safe
- End-products are safe