Cryogenics - Introduction and Applications

Cryogenics  

Cryo - very cold (frost)
genics - to produce

• Cryogenics is the science and technology associated with generation of low temperature below 123 K.
• The branch of physics and engineering that involve the study of very low temperatures, how to produce them, and how material behave at those temperatures.

History

The development of cryogenics as a low temperature science is a direct result of attempts by 19th century scientists to liquefy the permanent gases.

One of these scientists Michael Farady, had succeeded by 1845 in liquefying most of the gases. His procedure consisted of cooling the gas by immersion in a bath of ether and dry ice and then pressurizing the gas until it is liquified.

The successful liquefaction of Oxygen was announced by physicist Louis Paul in 1877.

Milestones in history of cryogenic technology -

1845 - Liquefaction by Farady

1848 - Absolute Zero by Lord Kelvin

1877 - Cailletet & Pictet liquefied oxygen

1883 - Liquefied Nitrogen

1892 - Dewar developed a cryogenic vessel (use of silvering and vaccum in double walled glass vessels)

1895 - Linde and Hampson build air liquefiers with recuperative heat exchangers

1898 - Dewar Liquefied hydrogen 

1902 - Claude establish Air Liquid 

1907 - Linde establish first liquefaction plant in America

1908 - Kamerlingh Onnes - liquefies helium

1908 - Becquerel - freezes seeds and single cells

1911 - Onnes discovered superconductivity

1926 - Goddard fires the first cryogenic engine

1933 - Adbatic Demagnetization by Giaque 

1934 - Kapitza developed first expansion engine for Helium

1947 - Collins Cryostat developed

1958 - Multilayer cryogenic insulation developed

1966 - Helium dilution refrigrator was developed by Hall

Applications of cryogenics -

1. Electric power transmission in big cities
2. Frozen food and food preservation
3. Blood banking
4. In manufacturing process - cryogenic cooling is used to cool the tool tip at the time of machining. It increases the tool life.
5. In preservation of semen and biological specimen
6. Production of dry ice i.e solid carbon dioxide
7. Liquefaction of gases
8. Cryogenic engines for space applications
9. Alternative fuel for transport - cryogenic fuel
10. Cooling of supercomputers
11. Space propellants
12. In surgery 

Space Applications 

• Rocket Propulsion
• Cooling of Infra-Red (IR) Sensor
• Space simulation

Mechanical Applications

• Magnetic Separation
• Heat treatment
• Recycling

Gas Industry

• Liquefaction
• Separation
• Storage

Superconductivity

• NMR, MRI (Nuclear Magnetic Resonance, Magnetic Resonance Imaging)
• Maglev Locomotion
• Transformers and Generators

High Energy Physics

• CERN (European Organisation for Nuclear Research)
• ITER (International Thermonuclear Experimental Reactor)

Space Applications -

Rocket Propulsion

1. Cryogenic engines are powered by cryogenic propellants
2. Liquid hydrogen is used as a fuel to propel the rocket
3. Liquid oxygen is used as an oxidizer

Cooling of Infra-Red (IR) Sensors

1. Cooling of IR detectors, Telescopes, cold probes etc. are some of the major applications of cryogenics
2. Development of miniature and small cryo coolers for satellites for an improved accuracy and reliability of earth observation.

Space Simulation

1. Space simulation chambers are realistic environment for spacecraft. The cold space is simulated at cryogenic temperatures by use of LN2
2. The levels of vacuum required in space simulation chambers are very high. This is achieved by the use of cryo pumps and turbo molecular pumps.

Mechanical Applications

Magnetic Separation

Magnetic separation technique is used in variety of applications like enhancing the brightness of Kaolin, improving the quality of ultra high purity quartz etc.

Heat Treatment

The lives of the tools, die castings and their dies, forgings, jigs and fixtures etc. increase when subjected to cryogenic heat treatment.

Recycling

Cryogenic recycling turns the scrap into raw material by subjecting it to cryogenic temperatures.

This is mostly used for PVC rubbers

Gas Industry 

1. The transportation of gases across the world is done in liquid state. This is done by storing the liquid at cryogenic temperature.
2. Cryogens like LOX, LH2 are used in rocket propulsion.
3. Liquid Nitrogen is used as pre coolant in most of the cryogenic systems.
4. Nitrogen and Argon are primarily used to provide an inert atmosphere in chemical, metallurgical and welding industries

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