This document is a seminar report on cryogenic grinding submitted by Himanshu Tiwari to fulfill requirements for a Bachelor of Technology degree. Cryogenic grinding uses very low temperatures produced by liquid nitrogen to embrittle materials, making them easier to grind into smaller particles. Experimental studies showed cryogenic grinding of herbs resulted in 15.6% average increase in active constituents compared to normal grinding methods. Cryogenic grinding has applications in processing materials like steel, plastics, adhesives, spices and explosives due to advantages like reduced wear on equipment and ability to grind difficult composite materials.

1. UMA NATH SINGH INSTITUTE OF ENGINEERING & TECHNOLOGY
VEER BAHADUR SINGH PURVANCHAL UNIVERSITY JAUNPUR
A partial fulfillment of the degree
Of
BACHELOR OF TECHNOLOGY
SEMINAR REPORT
ON
“CRYOGENIC GRINDING”
SESSION - 2015-16
DEPARTMENT OF MECHANICAL ENGINEERING
SUBMITTED TO:- SUBMITTED BY:-
ER. APARNA SINGH GAUR HIMANSHU TIWARI
(ASSISTANT PROFESSOR) ROLL NO:- 213422
ER. DEEP PRAKASH SINGH B.TECH 3RD
YEAR 5TH
SEM
(ASSISTANT PROFESSOR)
(DEPTT. OF M.E).

2. U. N. S. I. E. T. V. B. S. P. U. JAUNPUR
CERTIFICATE
This is certify that the report work entitled “Cryogenic Grinding’’
submitted in partial fulfilment of the requirement for the degree of
bachelor of technology in “ MECHANICAL ENGINEERING” is a
bonafide seminar work carried out by Mr. Himanshu Tiwari under my
supervision and guidance .
Date- ………..
Place-…………
Er. Aparna Singh Gaur
( Assistant Professor)

3. CONTENT
CERTIFICATE i
ACKNOWLEDGEMENT 1
ABSTRACT 2
1. INTRODUCTION 3-4
2. APPLICATION OF CRYOGENICS 5
3. CRYOGENIC GRINDING PROCESS 6-8
4. CRYOGENIC GRINDING TECHNOLOGY 10-11
5. ADVANTAGE OF CRYOGENIC GRINDING 12
6. APPLICATION OF CRYOGENIC GRINDING 13
6.1. CRYOGRINDING OF STEEL 13
6.2. THERMOPLASTIC 13
6.3. THERMOSETS 13
6.4. ADHESIVE AND WAXES 13-14
6.5. EXPLOSIVES 14
6.6. SPICES 14
7. PROBLEM WITH CONVENTIONAL GRINDING 15
8. ADVANTAGES OF CRYOGRINDING WITH LIQUID
NITROGEN 16-17
9. WORKING OF CRYOGRINDING PLANT 18-19
10. RESULT OF EXPERIMENTAL STUDIES WITH
PEPPER 20
11. FUTURE PROSPECTS 21
12. REFERENCE 22

4. LIST OF FIGURE
1. RAPID EMBRITLEMENT OF TOUGH MATERIAL 7
2. CRYOGENIC GRINDING SYSTEM 8
3. TYPICAL CRYOGENIC GRINDING SYSTEM 9
4. SCHEMETIC PRESENTATION OF CRYGENIC GRINDER 11
5. DIFFERENCE BETWEEN CONVENTINAL AND CRYOGRINDING 17
6. CRYOGENIC GRINDING PLANT 19
7. GRAPHICAL REPRESENTATION OF CRYOGRINDING RESULT 19

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Acknowledgement
Every seminar big or small is successful largely due to the effort of a number of
wonderful people who have always given their valuable advice or lent a helping hand. I
sincerely appreciate the inspiration; support and guidance of all those people who have
been instrumental in making this project a success.
I wish to express sense of gratitude to my guide to Er. Aparna Singh Gaur, Er.
Deep Prakash Singh and Er. Awadhesh Kumar Mechanical Engineering Department.
Uma Nath Singh Institute of Engineering & Technology, Veer Bahadur Singh Purvanchal
University, Jaunpur, to give me guidance at every moment during my entire thesis and
giving valuable suggestions. He gives me unfailing inspiration and whole hearted co-
operation in caring out my seminar work. His continuous encouragement at each of work
and effort to push the work through are grateful acknowledged.
I am also very grateful to my classmates, for their huge co-operation and valuable
suggestion from time to time during my entire seminar work. I also extend my gratitude
to all members of the department without whose support at various stages this report will
not be materialized.
Last but not the least I wish to thanks my friends of B. Tech. 5th
semester and seniors
who helped me directly or indirectly in the successful completion of this work.
Date: ____________ HIMANSHU TIWARI
Place: ____________

6. 2 | P a g e
ABSTRACT
The term "Cryogenics" originates from Greek word which means creation or
production by means of cold. As prices for energy and raw materials rise and concern for
the environment makes safe waste disposal difficult and Costly, resource recovery
becomes a vital matter for today's business. Cryogenic grinding technology can
efficiently grind most tough materials and can also facilitate Cryogenic recycling of tough
composite materials and multi component scrap. The heart of this technology is the
CRYO-GRIND SYSTEM. It employs a cryogenic process to embrittle and grind
materials to achieve consistent particle size for a wide range of products. The cryogenic
process also has a unique capability for recycling difficult to separate composite
materials.
Cryogenic grinding is a method of powdering herbs at sub-zero temperatures
ranging from 0 to minus 70°F. The herbs are frozen with liquid nitrogen as they are being
ground. This process does not damage or alter the chemical composition of the plant in
any way. Normal grinding processes which do not use a cooling system can reach up to
200°F. These high temperatures can reduce volatile components and heat-sensitive
constituents in herbs. The cryogenic grinding process starts with air-dried herbs, rather
than freeze-dried herbs.
Solid materials are ground or pulverized by way of hammer mills, attrition mills,
granulators or other equipment. A smaller particle size is usually needed to enhance the
further processing of the solid, as in mixing with other materials. A finer particle also
helps in melting of rubber and plastics for molding. However, many materials are either
very soft or very tough at room temperatures. By cooling to cryogenic temperatures with
liquid nitrogen, these may be embrittled and easily fractured into small particles.

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1. INTRODUCTION
The science and technology of deep refrigeration processing occurring at temperatures
lower than about 150 k. is the field of cryogenics. The name cryogenics is evolved from
Greek word ‘kryos’ meaning icy cold. Phenomena that occurs at cryogenic temperatures
include liquefaction and solidification of ambient gases; loss of ductility and
embrittlement of some structural materials such as carbon steel; increase in thermal
conductivity to a maximum value, followed by further decrease in temperature.
Cryogenics is the low temperature (150 K) refrigeration.
It explains the properties of cryogens used and their principles. Storage methods
and handling techniques are covered. Cryogenics are applied in different fields of
production, transportation, medicine, aerospace, physics research etc. Rocket propulsion
is imparting force to a flying vehicle such as missile or spacecraft. Different types of
rockets and their parts are explained. Cryogenics has future applications in many fields
like superconductivity and propulsion fields. Cryogenics is being applied to variety of
research areas; a few of which are: food processing and refrigeration, space craft life
supporting system, space simulation, microbiology, medicine, surgery, electronics, data
processing and metal working. Rocket propulsion is the process of imparting a force to
flying vehicle such as a missile, by momentum of ejected matter.
The matter, called propellant, is stored in the vehicle and ejected at high velocity.
In chemical rocket, the propellants are chemical compounds that undergo a chemical
combustion reaction releasing the energy for thermodynamically accelerating and
ejecting the gaseous reaction products at high velocities. Chemical rocket propulsion is
thus differential from other types of rocket propulsion which use nuclear, solar or
electrical energy as their power source and which may use mechanism other than
adiabatic expansion of a gas for achieving high ejection velocities.
A scientifically controlled study using four herbs was conducted at Frontier Herbs in
the Fall of 1996, comparing cryogenic grinding methods with normal grinding methods.
The herbs tested included feverfew, goldenseal, valerian and echinacea. In all cases the
cryogenically ground herb contained greater amounts of the constituents tested. Feverfew

8. 4 | P a g e
herb showed the greatest difference, with the cryogenically ground herb containing
21.8% higher levels of parthenolide, the primary active constituent. Valerian root showed
an 18.7% increase in valerenic acid when cryogenically ground. Goldenseal root showed
a 16.4% increase in berberine and 10.7% increase in hydrastine. Lastly, Echinacea
purpurea root showed a 12.1% increase in total phenolic content in the cryogenically
ground root. Test results were obtained by HPLC (high performance liquid
chromatography) methods.
Cryogenic grinding was shown to significantly affect active constituent levels
in herbs. Test results showed an average increase of 15.6% in constituents tested in four
medicinal herbs when they were ground cryogenically. The range was 10.7% to 21.8%,
indicating that some herbs are affected more than others by the temperatures at which
they're ground.

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2. APPLICATION OF CRYOGENICS
The major areas in which cryogenics find its applications are : -
1. Gas Industry – in air separation. The volume of production of nitrogen and Oxygen by
cryogenic separation of air is the important of the separation of air, refrigeration and
separation. In the separation column, the difference in the boiling points of the
constituents of air is used to separate them out.
2. As the source of gas. For example, the breathing oxygen needed for the pilots of the
fighter aircraft is supplied by vaporizing liquid oxygen on board. In this way is a weight
reduction of 65% and space reduction of 85%.
3. In space research – as rocket propellant and for space simulation. The most important
advantage of cryogenic fuels is that these have very high specific impulse when compared
to other fuels (specific impulse is kgs of thrust produced per kg of propellant per sec).
The value is approximately 500 for cryogenic fuels whereas it is about 250 for alcohol
oxygen mixture.
4. In biology – for preservation and in treatment of diseases.
5. In food industry – for food handling and processing
6. In electronics – both semiconductor and superconductor electronics for better signal to
noise ratio speed etc
7. In miscellaneous applications such as cryogenic grinding , freezing pipelines for repairs,
shrink fitting, fire fighting, etc
8. In medicine – Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy (MRS),
Magneto Cardio Graphy (MCG), etc.
9. In nuclear and high – energy physics
10. Metal fabrication

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3. CRYOGENIC GRINDING PROCESS
Since almost all materials embrittle when exposed to cold temperatures,
cryogenic size reduction utilizes the cold energy available from liquid nitrogen to cool,
embrittle and inert materials prior to and or during the grinding process. All materials
which due to their specific properties at ambient temperatures are elastic, have low
melting points, contain volatile or oily substances, have low combustion temperatures
and are sensitive to oxygen, are ideal candidates for cryogenic size reduction.
Physical properties of liquid nitrogen is produced by the separation of air into
its components in an air separation plant and is distributed in vacuum insulated transport
vessels to the end user where it is stored in a vacuum insulated storage vessel till it is
used. At atmospheric pressure liquid nitrogen is at a temperature of –320 deg F and
possesses a latent energy content of 94 BTU/LB resulting in a total cooling energy content
of 179.6 BTU/LB. Nitrogen is anon-flammable, non toxic and inert gas which makes up
78.09% of the air we breathe. It has the characteristics of an inert gas, except at highly
elevated temperatures, and does not form any compound under normal temperatures and
pressure. Drawn from the liquid phase, nitrogen generally has a purity of 99.998 % with
a dew point less than – 100 deg F and is very dry.

11. 7 | P a g e
FIG:- Rapid embritlement of tough materials
Liquid Nitrogen at 77.6 K is used to embrittle a material prior to size
reduction. Once brittle the material is much easier to grind. When CRYO-GRIND system
is used to recycle composite or multi component materials, two separate phenomena
occur. First, since each component generally would have a different coefficient of thermal
contraction, high thermal stresses are created at the interface between the components
due to rapid cryogenic cooling. Second, because each component material embrittles at
different temperatures, it allows selective embritlement, which further enhances
separation effectiveness. The most brittle components will undergo greater size
reduction. Through careful control of thermal stress and embritlement with operating
temperature, cleaner separation and recovery of individual components are achieved.
Nylon
PP
Thermoplastics
PU,PE
Powder Coating
PVC
Colour
Concentrate
Thermo sets
polyester epoxy
Rubber
Elastomers
Silicon,
Natural
Rubber
Finer particle size
M
A
T
E
R
A
L
T
O
U
G
H
N
E
S
S

12. 8 | P a g e
Cryogenic Grinding System
When using the system, measurable and repeatable results are obtained for lab
or productions calculations. Mills range in size from 7-1/2 HP to 200 HP. With our
cryogenic grinding unit an understanding develops with interaction of equipment
components and operating parameters. Factors such as consistent feed rate, precise
temperature measurement, mill operating parameters and pressure control are critical to
the evaluation of cryogenic grinding and cryogenic grinding systems.
Fig:- Cryogenic Grinding System

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Fig:- typical cryogenic grinding system

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4. CRYOGENIC GRINDING TECHNOLOGY
For pulverizing many materials, cryogenic grinding technology increases
productivity and lowers power costs. Many elastic or "soft" materials are very difficult to
pulverize, requiring long cycle times and high energy consumption. This combination
decreased productivity and increased costs unnecessarily. Cryogenic grinding involves
cooling a material below its embrittlement temperature with a cryogenic fluid, typically
liquid nitrogen or, in certain applications, carbon dioxide. After cooling, the material is
fed into an impact mill where it is reduced in size primarily by brittle fracture. This
process has several benefits:
 Ability to process relatively "soft" or elastic materials that cannot otherwise
be ground
 Increased throughput
 Reduced power consumption
 Smaller size particles
 Minimal loss of volatile components
 Lower capital investment
Probably the greatest benefit provided by cryogenic grinding is the ability to
grind "soft" or elastic materials that otherwise could not be ground, or could be ground
only with long cycle times and high energy use. By embrittling the material, fine
powder or crumb can be obtained easily and with a minimum expenditure of energy.
Because embrittled material grinds easily, the throughput for a given mill is
substantially increased and less power is used per pound of material ground.
Cryogenic grinding also reduces the material to particle sizes difficult or
impossible to attain with ambient temperature grinding. The dry, cold, inert atmosphere
in which the grinding occurs minimizes reaction with the material and reduces the loss
of volatile components. When processing composite materials, cryogenic grinding
usually makes it easy to separate the various materials.
Cryogenic grinding is used for grinding spices, thermoplastics, elastomers,
color concentrates, and similar materials. It is also used to recover a variety of scrap
materials, such as factory scrap rubber and scrap tires, and to separate the components
in composite materials.

15. 11 | P a g e
Fig:- schematic presentation of cryogenic grinder

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5. ADVANTAGES OF CRYOGENIC GRINDING
 Smaller particles
 More uniform particle size distribution
 Efficient process
 Process cooling/temperature control
 Inertness
 Trial Facilities
 Can grind smaller rubber particles down to below 200 micron
 Regular particle size
 Efficient process by introducing minimum nitrogen and maximum throughput
 Improved surface morphology
 Increased throughput
 Low capacity motors required
 Reduced power consumption
 Smaller size particles
 Minimal loss of volatile components
 Improves the aroma by minimizing the loss of essential oils when compared
 with grinding at normal temperature
 Approx. 2 - 3 times higher grinding capacity

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6. APPLICATIONS OF CRYOGENIC GRINDING
6.1 CryoGrinding of steel
The large amount of thermal energy generated during machining and grinding
at high speed and feed rate raises the temperature at the cutting zones excessively. This
elevated temperature level under large cutting stresses accelerates plastic deformation
and wear of cutting edges leading to increased cutting forces and premature tool failure.
Cooling with conventional cutting fluids in the form of jet or mist is unable to solve the
problem. In such cases cryogenic cooling by agents like liquid nitrogen will improve the
situation. In the case of cryogenic grinding, the liquid nitrogen from a reservoir under air
pressure comes out a jet from a nozzle to the spot where cooling is desired. The jet
impinges on the work surface at the grinding point from a suitable distance and angle.
The amount of temperature reduction due to cryocooling will increase the grinding depth.
Because of the extreme cooling action, the life of the grinding wheels will be increased.
6.2 Thermoplastics
To which Nylon, PVC, Polyethylene, and polypropylene belong are commonly used
in powdered form, for but not limited to, a variety of applications such as adhesives,
powdered coatings, fillers, resins and plastics sintering and molding. These powders
generally can only be produced in high production rates and fine particle sizes utilizing
cryogenic size reduction.
6.3 Thermo sets
To which natural and synthetic rubbers belong are important recyclable materials.
Under cryogenic size reduction these materials can economically and at high production
rates be ground into fine powders, used as filler, be recycled.
6.4 Adhesives & Waxes
These materials at ambient temperature are generally pliable and sticky and when
ground would form excessive deposits in the mill building up heat, increasing energy
requirement and eventually shutting down the size reduction process. Under cryogenic

18. 14 | P a g e
temperatures these products become brittle and can be pulverized with much less energy
and without forming deposits.
6.5 Explosives
Explosives explode when their ignition temperature, in the presence of oxygen, is
achieved. Cryogenic size reduction performs two tasks when grinding explosives; it
reduces the temperature of the material well below its ignition temperature and removes
the oxygen from the system thereby eliminating the possibility of combustion. The
product to be ground is filled into the volumetric screw feeder where it is metered at a
specific rate into the cryogenic pre-cooler. In the cryogenic pre-cooler liquid nitrogen is
injected and combines with the product thereby cooling and embrittling the product. The
product is then transported, along with the cold gas generated by the evaporation of the
liquid nitrogen, to the grinding mill where it is pulverized. The pulverized product then
goes through a classifier where it is separated into various particle sizes and packaged.
Should oversize material exist this can be fed back into the volumetric feeder and recycled
into the system. The cold gas from the mill is recycled through the filter or bag-house and
makeup air back into the mill. Excessive cold gas is vented out. In addition the cold dry
nitrogen gas keeps both the classifier and bag-house free of moisture and inert, preventing
the possibility of dust explosions and buildup of product.
6.6 Spices
Spices like Pepper, cinnamon, chilly, Ginger, Cumin seed, Nutmeg, Glove etc., have
a characteristic taste and aroma. These characteristic qualities are essential in them to
have their value as ‘spice’. These qualities exist in them due to the presence of etheric
oils within. The etheric oils have their boiling points ranging down to 50o
C. During
conventional grinding, due to the heat produced by friction, the temperature of ground
spices shoots up to about 90o
C, where by most of the etheric oils oil off resulting in
inferior quality of the ground product. This inferior quality is evident by the reduced taste
and aroma.

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7. PROBLEMS WITH CONVENTION GRINDING
7.1 Loss of etheric oil
The applied energy gets dissipated in the form of heat (>99%) and hence the
temperature in the grinding zone rises to more than 90oC resulting in loss of etheric oils
whose boiling point vary from 50oC to 320oC. This results in the inferior quality of the
ground product.
7.2 Clogging and gumming of the mill
Spices like nutmeg, clove, cinnamon, etc.., contain high level of fat while
capsicum, chilli, etc, contain high moisture content. These cause clogging and gumming
of mill thus affecting the throughput and quality of the ground product. High moisture
content materials often stick to the parts of the mill.
7.3 Oxidation and related degradation:
Due to intimate cyclone effect of the air in the vicinity of grinding zone,
aromatic substances in materials oxidize and become rancid. In addition the formation of
fresh and exposed surfaces due to grinding, accelerates the process of oxidation.

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TRADITIONAL V/S CRYOGENIC GRINDING
8 ADVANTAGES OF CRYOGRINDING WITH LIQUID
NITROGEN
8.1 Higher retention of etheric oils
Due to lower operating temperatures, the etheric oils will be retained in the
product almost to the original level. Hence the ground product will obviously be better in
taste and aroma, with the improved value as ‘spice’.
8.2 Prevention of oxidation and rancidity
The heat developed during grinding will be absorbed by liquid nitrogen which in
turn will be converted to vapour. These vapours expel any air in the mill and produce an
inert atmosphere during grinding. This eliminates the possibility of oxidation. To add to
this, an inexpensive, dry and inert atmosphere for storage and package of ground product
is created.
8.3 Increased throughput and power saving
Due to usage of liquid nitrogen, the raw material becomes brittle. This in turn keeps
the oil and moisture content in the crystallized condition during grinding and avoids
clogging. At the same time when the material is brittle, less power is required to crush.
Thus cooling with liquid nitrogen increases the throughput due to reduction in specific
energy requirement.
8.4 Finer particle size
CryoGrinding results in finer particle sizes of the ground spices. This eliminates
speckling problems and reduces the settling rate of spice powders in liquid preparation.
8.5 Reduction in microbial load
By cooling with liquid nitrogen, some bacteria’s which some others may
become dormant. Thus, when the ground product is warmed to the room temperature (in
the inert atmosphere of nitrogen) one expects considerable reduction in microbial load.

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8.6 Possibility of fine grinding of difficult spices
By use of low temperatures, the raw materials become brittle which causes fibers to
shatter. Thus fibrous spices like ginger can be ground easily to finer particle size. High
oil content spices like nutmeg can be ground easily. CryoGrinding can be employed for
grinding green spices like chilies with no pre-drying and also with the retention of its
original colour.
Fig:- difference between conventional and cryogenic grinding

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9. WORKING OF CRYOGRINDING PLANT
The spice to be ground is cleaned manually and fed in to the hopper. From the
outlet of the hopper the spice enters in to the vibratory feeder, which is positioned with a
small inclination towards the entry of the helical screw conveyor. The vibratory feeder
has a provision to control the feed rate.
The helical screw conveyor has a total length of a metre where the fed material
travels horizontally to the grinding mill. The screw conveyor is driven by a 0.75 KW
drive with reduction gear and inverter control. Liquid nitrogen from a storage container
is sprayed into the screw conveyor. The time of stay of spice in the conveyor can be
adjusted by varying the speed of the drives. A censor monitors the temperature of the
ground spice and the liquid nitrogen spray is optimized using automatic feed back control.
The grinding mill is driven by a 5.5 KW, 3 – phase,50 Hz motor. The mill is
connected with the motor by a flat belt between the motor pulley and the mill pulley.
Inside the mill, stud disc is mounted on the shaft. The circularly projecting studs fit
between the similar projecting studs from the rear of the front door. The spice to be
ground gets locked between the studs of the rotating disc and studs of the stationary disc.
When the mill is running, the spice gets crushed between the studs and comes out through
an optional sieve as a ground product.
To the bottom of the mill a collecting bin is housed where the ground product
gets collected. The bottom of this tapering collecting bin, a rotary valve is mounted which
is driven by a 0.37 KW motor. The rotary valve has 8 compartments mounted radially in
the same plane. The product, which comes out of the rotary valve, is lifted to the storage
container by the Hapman Helix conveyor. This is driven by a 0.37 KW motor. The
vaporized nitrogen from the mill is sucked by a centrifugal blower and through the filter
assembly if fed back to the mill.

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CRYOGRINDING PLANT
Fig :- graphical representation of cryogrinding result

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10. RESULTS OF EXPERIMENTAL STUDIES WITH PEPPER
Experimental studies were carried out on the samples under different conditions:
10.1 Volatile oil content and flavor components
The pepper contains the oil-bearing cells mainly in the skin and towards the
tip of the cortex. When the pepper is ground these cells are broken and volatile oils and
flavour components evaporate causing aroma. In CryoGrinding higher percentage of oils
and flavor components are retained when compared with conventionally ground products.
The comparison is shown below.
SL.
NO.
COMPONENTS
CRYOGROUND
(%)
CONVENTIONAL
GROUND (%)
1. Moisture 13.00 11.00
2. Volatile Oil 2.61 1.15
3.
Flavour compounds
(relative
concentration) -
Pining
Limonene
1.40
8.30
0.29
1.18
10.2 Throughput of the Mill
For a constant current of 6A, the throughput of the mill by CryoGrinding was
50 Kg/hour (at-50oC), which was 2.25 times than that of conventional grinding producing
a throughput of 22 Kg/hour. This analysis clearly illustrates a throughput of 225 kg/hour
(against the rated throughput of 100 kg/hour by conventional method at room
temperature) could be easily be attained by CryoGrinding by suitable modification of the
screw cooler and by vibratory feeder.

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11. FUTURE PROSPECTS
 As the cost of raw materials and energy is increasing day by day, it is very necessary to
use optimum quantity and at the same time getting the required quality.
 By using CryoGrinding technology these aspects can be met efficiently. By using this we
can also recycle tough and composite materials. It has many significant advantages over
conventional grinding. This also leads to value addition to the product.
 CryoGrinding is economically viable, if liquid nitrogen costs are not formidable. By
adopting CryoGrinding technology the leading spice industries of our country will earn
considerable foreign exchange by exporting more value added processed spices, in place
of exporting whole spices.
 The technique can be easily extended to processing of PVC and industrial waste plastics
in view of recycling of non-biodegradable materials.

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12. REFERENCE
 Mc Graw Hill Encyclopedia of science & technology: 7th Edition VOL-4
 Proceeding of the 18th
International Cryogenic Engineering Conference (Edited by
K.G. Narayankhedhar, Narosa Publishing House)
 www.csa.fnal.gov Cold Facts (The quarterly magazine of the Cryogenic
Society of America).