Cryogenic Grinding
Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
computer science crazy
Super Moderator
******

Posts: 3,048
Joined: Dec 2008
#1
20-09-2008, 10:51 PM


Cryogenic grinding permits heat-sensitive, thermoplastic, and elastic materials to be economically ground to very small particle sizes. The cryogenic process actually embrittle a material prior to size reduction and controls heat buildup in the grinding equipment. The result is high product quality and system productivity.
Cryogenic grinding involves cooling a material below its embitterment 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
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..
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
Reply
ajukrishnan
Moderator
*****

Posts: 213
Joined: Dec 2009
#2
14-12-2009, 08:48 PM

A seminar and presentation report pdf for the above topic can be found at:
tkichina6780-sou/6780-3/58.pdf
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
Reply
seminar topics
Active In SP
**

Posts: 559
Joined: Mar 2010
#3
21-03-2010, 02:08 PM

please read topicideashow-to-cryogenic-grinding--5420 for Cryogenic Grinding technical information and seminar and presentation report
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
Reply
seminar class
Active In SP
**

Posts: 5,361
Joined: Feb 2011
#4
24-02-2011, 11:30 AM

PRESENTED BY:
Ankit Kr. Methi


.docx   Cryogenic grinding.docx (Size: 1,017.17 KB / Downloads: 245)
ABSTRACT
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.
Cryogenic Grinding is also use 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
INTRODUCTION
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.
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 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.
Reply
seminar addict
Super Moderator
******

Posts: 6,592
Joined: Jul 2011
#5
11-02-2012, 01:20 PM

to get information about the topic cryogenic grinding full report ,ppt and related topic refer the link bellow

topicideashow-to-cryogenic-grinding--108

topicideashow-to-cryogenic-grinding--2990

topicideashow-to-cryogenic-grinding

topicideashow-to-cryogenic-grinding-technology

topicideashow-to-cryogenic-grinding--5420?pid=33690#pid33690

topicideashow-to-cryogenic-grinding?pid=37866
Reply
seminar flower
Super Moderator
******

Posts: 10,120
Joined: Apr 2012
#6
02-10-2012, 03:19 PM

Cryogenic Grinding


.doc   Cryogenic.doc (Size: 131.5 KB / Downloads: 16)

Introduction

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.

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.

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.

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.

PROBLEMS WITH CONVENTION GRINDING

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.

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.

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.

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.

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 project and implimentationing studs fit between the similar project and implimentationing 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.
Reply

Important Note..!

If you are not satisfied with above reply ,..Please

ASK HERE

So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page

Quick Reply
Message
Type your reply to this message here.


Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  grinding wheel selection ppt jaseelati 0 143 06-02-2015, 03:14 PM
Last Post: jaseelati
  cryogenic rocket engine ppt jaseelati 0 278 13-01-2015, 01:40 PM
Last Post: jaseelati
  Seminar Report on CRYOGENIC ENGINE IN ROCKET PROPULSION seminar projects maker 0 3,294 26-09-2013, 04:44 PM
Last Post: seminar projects maker
  The Effects of Cold and Cryogenic Treatments on the Machinability Report seminar projects maker 0 363 13-09-2013, 04:51 PM
Last Post: seminar projects maker
  Grinding Attachments For Lathe Report study tips 0 671 05-03-2013, 01:13 PM
Last Post: study tips
  ELECTROCHEMICAL GRINDING ppt project girl 0 726 08-01-2013, 12:11 PM
Last Post: project girl
  GRINDING MACHINES seminar tips 0 379 19-12-2012, 02:49 PM
Last Post: seminar tips
  MILLING-GRINDING-DRILLING AND SLOTTING ATTACHMENT ppt seminar flower 1 1,536 03-12-2012, 11:32 AM
Last Post: seminar tips
  Cryogenic grinding: an independent voice project girl 0 411 29-11-2012, 04:21 PM
Last Post: project girl
  Electro chemical grinding seminar tips 0 460 15-11-2012, 06:13 PM
Last Post: seminar tips