Two gases often used in their liquid forms are nitrogen and helium. Liquid nitrogen is used in many cryogenic cooling systems. Liquid nitrogen is a valuable coolant because of its low boiling point, inexpensive price, and low toxicity. It is popular as a cost-effective way to cool down a chemical reaction, to temperatures below -40°C and facilitate faster reactions with complete temperature control.
Benefits of using a Liquid Nitrogen Heat Exchangers are:
- These engineered systems provide an economical solution for
direct, semi-direct or indirect cooling methods.
- No matter what the reaction level is, the reaction temperature
can be controlled by balancing, increasing or decreasing the flow of
- With few moving parts and simple temperature controllers, the
systems are reliable and easy to maintain.
- The power of liquid nitrogen as a refrigerant, coupled with
uniformity of the exchange fluid, ensures perfect chemical reaction
- Indirect cooling can also be achieved by cooling a circulated
heat transfer fluid within a liquid nitrogen cooled exchanger.
- Liquid nitrogen can be delivered directly to the site and can be
re-used in other plant processes to improve overall process
- Liquid nitrogen is capable of changing temperature many times
faster than a mechanical refrigerated cooling system. Faster
temperature change decreases total test time thereby increasing
testing efficiency and saving money.
- Liquid nitrogen exchanger require considerably less space than a
mechanically refrigerated chamber because of absence of large
compressors and condensers.
- There are no adverse environmental effects from discharging the nitrogen gas into the environment, however, other cooling refrigerants contain CFCs that contribute heavily to ozone layer depletion.