Thursday, December 6, 2018

Useful Facts About Cryogenic Gases

By Laura Williams


Gases that have been liquefied and kept at exceedingly low temperatures in their liquescent state are known as cryogenic liquids. Other names that are used to denote these substances include deeply refrigerated gases, cryogenic liquefied gasses and refrigerated liquefied gases. Vaporized cryogenic liquids normally form cryogenic gases. In commercial and industrial settings, these elements have a lot of uses.

In one case, these gasses are used because of their low temperature properties. For instance, very low temperatures in the gases are used to contract components in machinery to allow them to form tight joints with other components. Another application is that freezing gasses makes it possible to transport it in extremely large quantities. For instance, between 690 and 850 liters of the gas only forms a single liter of the liquid, which can then be transported with much ease.

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.

Blockages in vessels, equipment and pipes due to humidity and moisture freezing inside the pipe are normally caused by cryogens. The cold quality of cryogens results in the freezing. Apparatus such as stop valves, safety valves, instrument lines and pressure gauges may cease to function correctly due to ice formation. This could lead to a major safety accident or hazard if not corrected.

Cryogens are known for causing catastrophic failure or rupturing of equipment and containers. The rupture is caused by a buildup of pressure caused by vaporization of cryogenic liquid. The liquid vaporizes as it absorbs thermal energy from the surrounding, causing a buildup of pressure.




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