What is Dry Ice?

Dry Ice?

Even though the two words may seem mutually exclusive, it is exactly what makes dry ice special. As opposed to normal ice, dry ice is not made by freezing water, but out of pure carbon dioxide (CO₂). The CO₂ is pumped into a piston where it is subsequently compressed with a pressure of 180bar. The application of the pressure causes the carbon dioxide to change its physical state from liquid to solid as it cools down to a temperature of -78,5°C (-109.3°F). This extreme cold makes dry ice dangerous to handle without an appropriate protection due to burns caused by freezing. When the carbon dioxide reaches its solid state, it can be forms into pellets, nuggets or blocks. Because it does not consist of water, the “melting process” – sublimation – takes place without any residue, as the dry ice changes directly from its solid to gaseous state.

Dry ice is truly a versatile and well-rounded product. Given a temperature as low as -78^oC, it can be used as an extremely helpful cooling agent or for dry ice blasting in industries.

Its rising popularity has also entered into private households as more and more customers rely on dry ice for cooling. From camping trips to catering, dry ice in a well-isolated container can keep your food and beverages cold up to several days.

Did You Know...

Dry ice was not invented. In the early 1830s, its unique properties have been discovered, and eventually commercialized in the 1920s.
In the early 20th century, dry ice was used as a cooling agent in private households, long before electricity was available.
Dry ice is non-polar, with a dipole moment of zero. The density of dry ice varies, but usually ranges between about 1.4 and 1.6 g/cm3 (87 and 100 lb/cu ft). It has a very low thermal and electrical conductivity.
Dry ice doesn’t melt, it sublimes. That means it changes from its solid state straight to gaseous.
It is the same chemical that makes soda fizzy.
Dry ice is non-toxic, but the surface is too cold to be touched without protective gloves.
Dry ice is gaining popularity in molecular cuisine – the consumption speaks for itself!
Various medical fields start to recognise the significance of dry ice: be it cold caps for chemotherapy or different cryogenic applications in cosmetics.

Dry Ice Safety Guidelines

Handling and Storage of Dry Ice

Dry ice converts into carbon dioxide gas. In a confined space, the CO2 level will rise too high and displace oxygen, creating a suffocation hazard.
Never handle dry ice with your bare hands. Always wear thermal gloves to reduce the risk of thermal burns to the skin.
Store and use dry ice with adequate ventilation.
Do not store dry ice in an airtight container. When dry ice sublimates to carbon dioxide, the gas pressure greatly expands. This expansion will cause the airtight container to expand and possibly explode.
Keep dry ice away from children.
Do not put dry ice in the mouth.

Transport

Avoid transporting dry ice in the trunk or passenger compartment of a vehicle; it should only be transported when fully separated from the driver and passengers. If it is unavoidable, the load shall be well insulated and secured, and there should be adequate ventilation. If at any point when dry ice is present and you begin to feel unwell, experience rapid breathing or cyanosis, you must leave the area immediately and seek help. This could indicate that you have inhaled too much carbon dioxide and not enough oxygen.

How Dry Ice Blasting Works

Dry ice blasting is a technological novelty used for cleaning surfaces that are otherwise too complicated to do so. The method is similar to sand or glass bead blasting, in that it cleans surfaces when blasted with high air pressure. However, that is all there is to the similarity: dry ice blasting is non-abrasive, which means the pollutant is not being scraped off. Instead, the low temperature cools the surfaces down, causing the pollutant to shock freeze and eventually being blasted off by the pressurised air stream. The remaining dry ice subsequently sublimates and leaves no residue; the pollutant can now be swept off.

Image courtesy of Cold Jet Deutschland GmbH.

Advantages of Dry Ice Blasting over Other Cleaning Methods

Dry ice is a non-abrasive, non-flammable blasting medium.
By foregoing secondary chemical cleaning agents, there are no additional requirements from the Department of Environment.
Machines do not have to cool down before being cleaned, almost no disassembling required.
The cleaning process doesn’t involve water, therefore sensitive machine parts can be cleaned without difficulty.
Dry ice is food-safe and sterile, and therefore approved for usage in the food industry as well as medical field.
The cleaning process is notably eco-friendly, as no additional carbon dioxide is released into the atmosphere.
This method is exceedingly time-saving and thus minimizes production downtime.
Dry ice blasting is strongly recommended when cleaning small holes, joints, and other places that are difficult to reach.