Introduction to Cryo technology Branch that talks below -180C Cryogenics Introduction to Cryo technology Branch that talks below -180C

The cooling of materials to extremely low temperatures using highly condensed gases. Cryogenic process A very low-temperature process used for separating substances, such as nitrogen and oxygen in air, that are gases at normal ambient conditions. Foods can also be preserved at very low temperatures using solid carbon dioxide or liquid nitrogen.

Father and Pioneers of Cryo Club World Father :- Dr. Jean Rostand Pioneer:- Prof. Robert CW Ettinger India Father :- Dr. Vasudevan Gnana Gandhi Pioneer:- Dr. V. Gandhi et al.

Chemical Engineers as Cryogenicist We mainly study cryogenics in final year of Bachelor degree programme. In which properties, handling, selection and safety of ‘cryogenic liquids’ is learned. Generally cryogenics for chemical engineers is concerned to liquefy gases like Nitrogen, Oxygen, He, Ar, etc.

We already have studied production of oxygen and nitrogen in IPT (CM-502) by Linde and Kellog’s Process. There are different cycles by which liquefication of gas can be done. Linde Cycle Claude Cycle Cascades It includes high pressure cycle in which more than one compressor is used i.e. gas is expanded twice. A fraction of gas is expanded in a high speed expander but if large amount of liquid is formed in expander the efficiency of the process will be decreased.

Linde - Frankl cycle producing low purity oxygen and nitrogen

Helium by Claude Process

Production of helium by cascade process

Argon liquefaction

Properties of cryogenic fluids Liquid Oxygen Blue coloured due to long-chain molecule O4. Boils at 90.18 K and freezes at 54.4 K. Density = 1141kg/m3. Oxygen is paramagnetic while other cryogenic liquids are non magnetic. Liquid Nitrogen Clear, colourless liquid. Boils at 77.36 K and freezes at 63.2 K Density = 807 kg/m3.

Liquid Fluorine A light yellow liquid. Normal boiling point of 85.24 K. It is one of the most dense cryogenic liq (  1507 kg/m3.) It is highly toxic. Liquid Argon Clear, colourless liquid. Inert and nontoxic. Boils at 87.3 K and freezes at 83.8 K. Liquid Helium Principal component of natural gas. Boils at 1 atm at 111.7 K and freezes at 88.7 K.

Applications of cryogenics Rocket propulsion Electronics High energy physics Space simulation Manufacturing process Recycling of material

References Mukhopadhyaya; Fundamentals of cryogenic Engg; PHI Thomas M, Flynn, Dehher; Cryogenic Engineering; Marcel-Decker, Colorado P, Florida

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