Raw material
1. Carbon dioxide
Process
1. Carbon dioxide is liquefied by compressing and cooling.
2. The liquid carbon dioxide is held under pressure and kept refrigerated so that it remains in liquid state.
2. The liquid carbon dioxide is held under pressure and kept refrigerated so that it remains in liquid state.
3. Liquid carbon dioxide is released into dry ice press. When the liquid moves from a highly-pressurized environment to atmospheric pressure, it expands and evaporates at high speeds causing the liquid to cool to its freezing point which is −78.3°C. A nozzle puts the liquid into the top block of a dry ice press. This press includes a large block at the top that can exert extreme pressure on the product that is brought into it. When the liquid carbon dioxide hits the block of the dry ice press, it immediately solidifies. The carbon dioxide now resembles snow.
4. This snow is compressed into a block of dry ice.
Product
Dry ice (also referred to as "Cardice" or "card ice" - the solid form of carbon dioxide)
Used for/in
Preserving food; flash freezing food, laboratory biological samples, and carbonated beverages; making ice-cream; arresting and preventing insect activity in closed containers of grains and grain products; fog machines; freezing and removing warts; bait to trap mosquitoes, bedbugs, and other insects due to their attraction to carbon dioxide; plumbing (plumbers use an equipment that forces pressurized liquid CO2 into a jacket around a pipe and the dry ice formed causes the water to freeze, forming an ice plug allowing them to perform repairs without turning off the water mains)
Production facility
Kwinana, WA
Export
Port Moresby, Papua New Guinea
The process you manufacture dry ice is most interesting.
ReplyDeleteMy comments:
1. Could you also include the temperature of liquid carbon dioxide?
2. It is most interesting to note that liquid carbon dioxide at some -ve deg Celsius could solidifies at room temperature! One would expect only after liquid carbon dioxide is subjected to further cooling it would solidify! Could you explain this phenomena?
I have previously made an error in my process which I only realise after reading your comment. I left out a step and have now rectified it. Thank you for the comment.
ReplyDeleteAn interesting point to note is that carbon dioxide has no liquid state at pressures below 5.1 standard atmospheres (520 kPa). At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below −78 °C and the solid sublimes directly to a gas above −78 °C. In its solid state, carbon dioxide is commonly called dry ice.
The phenomenon that "carbon dioxide solidifies at room temperature" is that it was previously kept in a highly-pressurized environment and is then released to atmospheric pressure. It expands and evaporates at high speeds causing the liquid to cool to its freezing point which is −78.3°C.
The statement "it immediately solidifies since it is now at room temperature" is misleading. I have now corrected the sentence.
ReplyDelete