Useful Facts About Cryogenic Gases

By Laura Williams


Cryogenic liquids refer to gasses that have been liquefied and stored in their liquid state at extremely low temperatures. There are other names that are used to refer to these substances, which include cryogenic liquefied gasses, refrigerated liquefied gases, and deeply refrigerated gases. Cryogenic gases are usually formed from cryogenic liquids that have been vaporized. These substances have very many applications in industrial and commercial settings.

The low temperature properties of these gasses makes them very useful in a wide range of applications. For example, very low temperatures in the gases are applied in contracting components for machinery. This is done to enable components to form very tight joints with each other. The other application is that frozen gasses take up much less space making it easier to transport large amounts easily. For example, one liter of the liquid is only formed by around 690 to 850 liters of the gas. This can be ferried much easily.

The typical boing point of these gasses is below -150 degree Celsius. However, there are a few exceptions to this rule. For instance, even though nitrous oxide and carbon dioxide boil at much higher temperatures, they are still considered as cryogens. Nitrous Oxide boils at -88.5 degrees Celsius while carbon dioxide boils at -78.5 degrees Celsius. Many other cryogens boil at much lower temperatures, with helium boiling at -269 degrees.

Cryogens are important and hazardous to animal and human life. This is because they have various properties that make them dangerous. For example, these gasses generate severe cold burns as soon as they come in contact with bare skin or eyes. This is due to low temperatures. The tissue will immediately get damaged when a person comes in contact with uninsulated equipment or pipes applied in storage or transportation of cryogens.

The damage to the tissue that is experienced is similar to that caused by a hot source. In case of the skin or eyes being sprayed with a stream of the gas, immediate freezing will occur. For that reason, it is very important to wear proper protective gear when handling these substances. One is required to wear protective clothing and gloves to avoid the adverse effects that the gasses have on the body.

The bad effect of cryogens also occurs on plastic, steel and certain kinds of rubber. These materials become brittle when exposed to cryogens, rendering them vulnerable to failure when subjected to the least amount of pressure. On the other hand, some materials are allowed to preserve their ductility since they do not experience brittle transition when subjected to low temperatures. Aluminum, brass, stainless steel, copper and certain plastics are such materials.

Cryogens usually cause blockages in pipes, vessels, and equipment as a result of freezing of moisture and humidity inside. The freezing results from the cold nature of cryogens. As a result of the formation of ice, instrument lines, stop valves, pressure gauges, and safety valves among other apparatus may stop to operate correctly. If not corrected, this could cause a major safety hazard or accident.

Rupturing of containers and equipment or catastrophic failure are problems known to originate from cryogens. Vaporization of cryogenic liquid generates a buildup of pressure which causes the rupture. As the liquid absorbs thermal energy within its surrounding, it vaporizes, causing a huge pressure buildup.




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