cryogenic grinding

[summer project pal]

Cryogenic Grinding

Presented by,
CYRIL GEORGE
Roll No:14
S7 ME

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Introduction
GRINDING PROCESS USING THE PRICIPLE OF CRYOGENICS.
USED FOR GRINDING RUBBER,PLASTICS,SPICES.
USES LIQUID NITROGEN AS CROGENIC FLUID.
MILL OPERATION WITH LIQUID NITROGEN CAUSES FEED MATERIAL TO BECOME BRITTLE.
PROVIDES DIMENSIONAL STABILITY AND INCREASED WEAR RESISTANCE.
PARTICLE CAN BE GROUND BELOW 400 MICRON PARTICLE SIZE.

Properties of Liquid Nitrogen

Molecular Weight : 28.01

Boiling Point @ 1 atm : -195.8°C, 77oK

Freezing Point @ 1 atm : -210.0°C, 63oK

Critical Temperature : -146.9°C

Critical Pressure : 33.5 atm
Properties of Liquid Nitrogen
Minimum effective temperature for some common refrigerants.
Grinding processes using liquid nitrogen


Working
Containers
Factors affect liquid nitrogen consumption in cryogenic grinding
Cryogenic grinding of Herbs
Cryogenic grinding plant for Spices
Cryogenic grinding plant for thermoplastics
Other applications
Pin Mill for Cryogenic Ultrafine Grinding
Advantages
Disadvantages
Grinding inorganic materials especially with large particle sizes is not economical.

Conclusion
Mill operation with liquid nitrogen causes the feed material to become brittle.
The specific precrushing energy is reduced meaning that the mill achieves high levels of grinding performance.
Additionally the cryogenic mode prevents grinding losses and thermal damage to the feed material that would otherwise be caused by the volatisation or overheating
of constituent ingredients.
The inert gas atmosphere provides a high degree of
safety when grinding flammable and potentially explosive products.
THANK YOU