Is Liquid Nitrogen expensive to produce?

Question

Is Liquid Nitrogen expensive to produce?

Answer 1

It is extremely expensive to produce, from the liquefaction and fractional distillation of clean, dry Air.

1..Equipment to clean and dry the air thoroughly.

2..For the liquefaction process, you will need a compressor capable of producing a pressure of at least 35 atmospheres (Critical Pressure of Air).

3..A refrigeration system to cool to Cryogenic Temperatures (Critical Temperature of air for this is -145°C)

4..The necessary Fractional distillation equipment to separate the Nitrogen from the Liquefied air.

(Many years working with Cryogenic fluids Producing LNG at -165°C).

Higher boiling gases like CO2 and Water vapour ..etc, MUST be completely removed (hence, Clean, Dry Air). These will solidify at cryogenic temperatures causing blockage of equiment in next to no time.

Answer 2

Comercial plants are very large and expensive to set up however once set up the raw materials needed to produce Nitrogen is air and that is free !

Simply compress and refrigerate air to fractionally distill it, as the different gasses in air will liquify at different temperatures and sparate into the component gasses at different temperatures producing 70 % nitrogen 23 % oxygen 2% carbon dioxide.

Answer 3

it is if you don't have access to the materials or are not qualified

Answer 4

If you have the right kind of storage Dewar to receive it into, you can buy it.  There is no way you can do it cheaply on a small scale.

Answer 5

A few years back the industrial cost for LN was comparable to milk (i.e. around $1/gallon) but this is on a bulk basis like if you have a big storage tank serviced by Air Products or Parxair or somebody.  It's relatively cheap in bulk but only because of scale. As others have said the plants required to generate refrigerated liquid N2 from the atmosphere are costly to build and operate.

Answer 6

It is expensive to set up the cooling plant and expensive to run in terms of energy costs. Most labs just buy it in insulated buckets as they need it.

Answer 7

If your not a lab technician or chemical engineer then yes.