Guidelines To Manage Hazardous Liquid Nitrogen

By Author: Julian Booth
Total Articles: 10
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Nitrogen is a non-toxic, odorless, colorless and non-flammable element. Liquid nitrogen is its liquefied form existing at a very low temperature and commercially produced by fractional distillation of liquid air. It is best used for cryogenic applications that range from freezing & transport of food products, cryopreservation of biological samples to cryotherapy to remove skin lesions and as coolant for superconductors, vacuum pumps etc.
However, liquid nitrogen can be hazardous if not taken care. It can cause severe frostbite upon contact with living tissue. Or another dangerous outcome can be asphyxiation which results when greater amount of nitrogen gets mixed up with the air and reduces relative amount of oxygen. This can cause difficulty in breathing especially in confined spaces like laboratory. Hence, liquid nitrogen requires great care while handling and should be stored in proper containers.

There are two kinds of nitrogen containers based on the state of nitrogen that needs to be stored. Compressed gas cylinders are used to store gaseous nitrogen while for its liquid form, its liquid nitrogen containers. ...
... These liquid nitrogen tanks can hold the liquid nitrogen at an adequate pressure to sustain a particular required temperature. To store and transport this chemical safely, liquid nitrogen containers are best option as they are rugged vessels that can sustain physical damage or high temperature to some extent.

Another type of liquid nitrogen container is cryogenic dewar. Cryogenic dewars are specialized vacuum flask whose boiling points are significantly lower as compared to room temperature. All liquid nitrogen dewars have a double-walled, vacuum vessel with multi-layer insulation to maintain high vacuum between the layers. This assembly provides thermal insulation which reduces the rate of content boiling away. They can also resist pressure and impact.

Though cryogenic dewars are more stable than liquid nitrogen containers, they must be handled with extreme care. The empty ones can also be unsafe as they still have a lot of pressure inside.

Julian Booth is an expert provider of cryogenic dewars and liquid nitrogen dewars.