21-03-2010, 01:53 PM
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1. INTRODUCTION
The science and technology of deep refrigeration processing occurring at temperature lower than about 150 k. is the field of cryogenics. The name cryogenics is evolved from Greek word ËœCryosâ„¢ 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.
The origin of cryogenics as a scientific discipline coincided with the discovery by nineteenth-century scientists that the permanent gases can be liquefied at exceedingly low temperatures. Consequently, the term "cryogenic" applies to temperatures from approximately -100°C (-148°F) down to absolute zero (the coldest point a material could reach). In 1848, English physicist William Thomson (later known as Lord Kelvin; 1824“1907) pointed out the possibility of having a material in which particles had ceased all forms of motion.
The absence of all forms of motion would result in a complete absence of heat and temperature. Thomson defined that condition as absolute zero.
2. HISTROY
Cryogenics developed in the nineteenth century as a result of efforts by scientists to liquefy the permanent gases. One of the most successful of these scientists was English physicist Michael Faraday (1791“1867). By 1845, Faraday had managed to liquefy most permanent gases then known to exist. His procedure consisted of cooling the gas by immersion in a bath of ether and dry ice and then pressurizing the gas until it liquefied.
Six gases, however, resisted every attempt at liquefaction and were known at the time as permanent gases. They were oxygen, hydrogen, nitrogen, carbon monoxide, methane, and nitric oxide. The noble gasesâ€helium, neon, argon, krypton, and xenonâ€were yet to be discovered. Of the known permanent gases, oxygen and nitrogen (the primary constituents of air), received the most attention.
For many years investigators labored to liquefy air. Finally, in 1877, Louis Cailletet (1832“1913) in France and Raoul Pictet (1846“1929) in Switzerland succeeded in producing the first droplets of liquid air. Then, in 1883, the first measurable quantity of liquid oxygen was produced by S. F. von Wroblewski (1845“1888) at the University of Krakow. Oxygen was found to liquefy at 90 K, and nitrogen at 77 K.
Following the liquefaction of air, a race to liquefy hydrogen ensued. James Dewar (1842“1923), a Scottish chemist, succeeded in 1898. He found the boiling point of hydrogen to be a frosty 20 K. In the same year, Dewar succeeded in freezing hydrogen, thus reaching the lowest temperature achieved to that time, 14 K. Along the way, argon was discovered (1894) as an impurity in liquid nitrogen. Somewhat later, krypton and xenon were discovered (1898) during the fractional distillation of liquid argon. (Fractional distillation is accomplished by liquefying a mixture of gases, each of which has a different boiling point. When the mixture is evaporated, the gas with the highest boiling point evaporates first, followed by the gas with the second highest boiling point, and so on.)
Each of the newly discovered gases condensed at temperatures higher than the boiling point of hydrogen but lower than 173 K. The last element to be liquefied was helium gas. First discovered in 1868 in the spectrum of the Sun and later on Earth (1885), helium has the lowest boiling point of any known substance. In 1908, Dutch physicist Heike Kamerlingh Onnes (1853“1926) finally succeeded in liquefying helium at a temperature of 4.2 K.
2.1 Words to Know:
Absolute zero: The lowest temperature possible at which all molecular motion ceases. It is equal to -273°C (-459°F).
Kelvin temperature scale: A temperature scale based on absolute zero with a unit, called the Kelvin, having the same size as a Celsius degree.
Superconductivity: The ability of a material to conduct electricity without resistance. An electrical current in a superconductive ring will flow indefinitely if a low temperature (about -260°C) is maintained.
3. METHODS OF PRODUCING CRYOGENIC TEMPERATURES
Cryogenic conditions are produced by one of four basic techniques:
1. Heat conduction,
2. Evaporative cooling,
3. Cooling by rapid expansion (the Joule-Thomson effect), and
4. Adiabatic demagnetization.
The first two are well known in terms of everyday experience. The third is less well known but is commonly used in ordinary refrigeration and air conditioning units, as well as in cryogenic applications. The fourth process is used primarily in cryogenic applications and provides a means of approaching absolute zero.
3.1 HEAT CONDUCTION TECHNIQUE:
Heat conduction is a relatively simple concept to understand. When two bodies are in contact, heat flows from the body with the higher temperature to the body with a lower temperature. Conduction can occur between any and all forms of matter, whether gas, liquid, or solid. It is essential in the production of cryogenic temperatures and environments. For example, samples may be cooled to cryogenic temperatures by immersing them directly in a cryogenic liquid or by placing them in an atmosphere cooled by cryogenic refrigeration. In either case, the sample cools by conduction (or transfer) of heat to its colder surroundings.
CRYOTUBES:
Cryotubes used to store strains of bacteria at low temperature. Bacteria are placed in little holes in the beads inside the tubes and then stored in liquid nitrogen.
3.2 EVOPARATIVE COOLING TECHNIQUE:
The second process for producing cryogenic conditions is evaporative cooling. Humans are familiar with this process because it is a mechanism by which our bodies lose heat. Atoms and molecules in the gaseous state are moving faster than atoms and molecules in the liquid state. Add heat energy to the particles in a liquid and they will become gaseous. Liquid perspiration on human skin behaves in this way. Perspiration absorbs body heat, becomes a gas, and evaporates from the skin. As a result of that heat loss, the body cools down.
Cryogens and Their Boiling Points
In cryogenics, a container of liquid is allowed to evaporate. Heat from within the liquid is used to convert particles at the surface of the liquid to gas. The gas is then pumped away. More heat from the liquid converts another surface layer of particles to the gaseous state, which is also pumped away. The longer this process continues, the more heat is removed from the liquid and the lower its temperature drops. Once some given temperature is reached, pumping continues at a reduced level in order to maintain the lower temperature. This method can be used to reduce the temperature of any liquid. For example, it can be used to reduce the temperature of liquid nitrogen to its freezing point or to lower the temperature of liquid helium to approximately 1 K.
3.3 COOLING BY RAPID EXPANSION (JOULES THOMSON EFFECT):
A third process makes use of the Joule-Thomson effect, which was discovered by English physicist James Prescott Joule (1818“1889), and William Thomson, Lord Kelvin, in 1852. The Joule-Thomson effect depends on the relationship of volume (bulk or mass), pressure, and temperature in a gas. Change any one of these three variables, and at least one of the other two (or both) will also change. Joule and Thomson found, for example, that allowing a gas to expand very rapidly causes its temperature to drop dramatically. Reducing the pressure on a gas accomplishes the same effect.
To cool a gas using the Joule-Thomson effect, the gas is first pumped into a container under high pressure. The container is fitted with a valve with a very small opening. When the valve is opened, the gas escapes from the container and expands quickly. At the same time, its temperature drops. The first great success for the Joule-Thomson effect in cryogenics was achieved by Kamerlingh Onnes in 1908 when he liquefied helium.
The Joule-Thomson effect is an important part of our lives today, even though we may not be aware of it. Ordinary household refrigerators and air conditioners operate on this principle. First, a gas is pressurized and cooled to an intermediate temperature by contact with a colder gas or liquid. Then, the gas is expanded, and its temperature drops still further. The heat needed to keep this cycle operating comes from the inside of the refrigerator or the interior of a room, producing the desired cooling effect.
3.4 ADIABATIC DEMAGNETIZATION TECHNIQUE:
The fourth process for producing cryogenic temperatures uses a phenomenon known as adiabatic demagnetization. Adiabatic demagnetization makes use of special substances known as paramagnetic salts. A paramagnetic salt consists of a very large collection of particles that act like tiny (atom-sized) magnets. Normally these magnetic particles are spread out in all possible directions. As a result, the salt itself is not magnetic. That condition changes when the salt is placed between the poles of a magnet. The magnetic field of the magnet causes all the tiny magnetic particles in the salt to line up in the same direction. The salt becomes magnetic, too.
At this exact moment, however, suppose that the external magnet is taken away and the paramagnetic salt is placed within a liquid. Almost immediately, the tiny magnetic particles within the salt return to their random, every-which-way condition. To make this change, however, the particles require an input of energy. In this example, the energy is taken from the liquid into which the salt was placed. As the liquid gives up energy to the paramagnetic salt, its temperature drops.
Adiabatic demagnetization has been used to produce some of the coldest temperatures ever observedâ€within a few thousandths of a degree Kelvin of absolute zero. A related process involving the magnetization and demagnetization of atomic nuclei is known as nuclear demagnetization. With nuclear demagnetization, temperatures within a few millionths of a degree of absolute zero have been reached.
4. APPLICATIONS
4.1 INDUSTRIAL APPLICATIONS:
Cryogenic treatment works on Reamers (carbide or HSS), Tool Bits, Tool Punches (carbide or HSS), Carbide Drills, Carbide Cutters, Milling Cutters, Files, Shaping Equipment, Scissors, Razors, Clippers, Knives, Band Saw Blades, Saw Blades, Reciprocating Blades, Saber Saw, Steel Woodworking and Form Tooling, Cutting Tools and Dies. In all cases, this treatment will result a stronger and more wear resistant metal.
4.2 AUTOMOTIVE APPLICATIONS:
Imagine a racer and crew who would normally tear down their engine after every race or two, suddenly discovering a process that would allow them to safely go up to 30 races or more without a major rebuild. Cryogenic treatment of automotive parts can certainly help make this a reality.
Cryogenics works with almost all metal engine parts. Pistons, rings, rockers, push rods, connecting rods, valves, the crank and camshaft and even the block itself. Together, a treated engine can last substantially longer in terms of wear than any other process could achieve. Even parts like brake rotors, drums, and brake pads can benefit from cryogenic treatment. Really, almost any part that is normally subject to wear can benefit. Just imagine what cryogenic treatment would do for the parts in your family vehicle!
4.3 MEDICL APPPLICATIONS:
Cryogenics has also been used by the medical industry. Surgical tools used by doctors, surgeons, dentists, and other specialistâ„¢s can all benefit from the increased wear resistance of the treatment. Surgical tools, like many other industrial tools, are expensive to replace, so cryogenic treatment can really pay off.
In addition, many surgical implants are also treated. This helps prevent the part from wearing, it increases the tensile and bending strength of the part, as well as reducing the likelihood of micro fracturing. Cryogenics really is a healthy choice for the medical field.
4.4 SPACE APPLICATIONS:
Cryogenic liquids are also used in the space program. For example, cryogenic materials are used to propel rockets into space. A tank of liquid hydrogen provides the fuel to be burned and a second tank of liquid oxygen is provided for combustion. Another space application of cryogenics is the use of liquid helium to cool orbiting infrared telescopes. Infrared telescopes detect objects in space not from the light they give off but from the infrared radiation (heat) they emit. However, the operation of the telescope itself also gives off heat. What can be done to prevent the instrument from being blinded by its own heat to the infrared radiation from stars The answer is to cool parts of the telescope with liquid helium. At the temperature of liquid helium (1.8 K) the telescope can easily pick up infrared radiation of the stars, whose temperature is about 3 K.
5. ADVANTAGES AND DISADVANTAGES
ADVANTAGES:
Cryogenics can produce large quantities of high purity (parts per billion contaminations) nitrogen. Some processes like the humid-air expansion process have a yield of about 40%-60% per pass, which allows you produce large quantities of nitrogen efficiently. Other processes, like the waste expansion, have a yield of about 25-40% per pass.
Cryogenic processes do not have economics of scale, i.e., expansion or reduction of product quantity requirements generally does not necessitate new equipment.
DISADVANTAGES:
Cryogenic processes in general have very large capital cost, due mostly to the cost of compressors and turbines. The high pressure requirements and the recovery of refrigeration energy explain the need for this equipment. Cryogenic separation requires the use of not only the compressors and turbines, but also numerous heat exchangers, insulators, and a distillation column; all of which add to the high costs of the process.
6. CONCLUSION
In this seminar report titled CRYOGENICS having the methods to produce the cryogenics temperatures and many advantages which are used for industries, automotives, medical field, space crafts, etc...This seminar report has given me more experience and knowledge on the cold generation and helped me to understand what cryogenics is, how it is produced, where it has been used and what is the use of cryogenics.
1. INTRODUCTION
The science and technology of deep refrigeration processing occurring at temperature lower than about 150 k. is the field of cryogenics. The name cryogenics is evolved from Greek word ËœCryosâ„¢ 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.
The origin of cryogenics as a scientific discipline coincided with the discovery by nineteenth-century scientists that the permanent gases can be liquefied at exceedingly low temperatures. Consequently, the term "cryogenic" applies to temperatures from approximately -100°C (-148°F) down to absolute zero (the coldest point a material could reach). In 1848, English physicist William Thomson (later known as Lord Kelvin; 1824“1907) pointed out the possibility of having a material in which particles had ceased all forms of motion.
The absence of all forms of motion would result in a complete absence of heat and temperature. Thomson defined that condition as absolute zero.
2. HISTROY
Cryogenics developed in the nineteenth century as a result of efforts by scientists to liquefy the permanent gases. One of the most successful of these scientists was English physicist Michael Faraday (1791“1867). By 1845, Faraday had managed to liquefy most permanent gases then known to exist. His procedure consisted of cooling the gas by immersion in a bath of ether and dry ice and then pressurizing the gas until it liquefied.
Six gases, however, resisted every attempt at liquefaction and were known at the time as permanent gases. They were oxygen, hydrogen, nitrogen, carbon monoxide, methane, and nitric oxide. The noble gasesâ€helium, neon, argon, krypton, and xenonâ€were yet to be discovered. Of the known permanent gases, oxygen and nitrogen (the primary constituents of air), received the most attention.
For many years investigators labored to liquefy air. Finally, in 1877, Louis Cailletet (1832“1913) in France and Raoul Pictet (1846“1929) in Switzerland succeeded in producing the first droplets of liquid air. Then, in 1883, the first measurable quantity of liquid oxygen was produced by S. F. von Wroblewski (1845“1888) at the University of Krakow. Oxygen was found to liquefy at 90 K, and nitrogen at 77 K.
Following the liquefaction of air, a race to liquefy hydrogen ensued. James Dewar (1842“1923), a Scottish chemist, succeeded in 1898. He found the boiling point of hydrogen to be a frosty 20 K. In the same year, Dewar succeeded in freezing hydrogen, thus reaching the lowest temperature achieved to that time, 14 K. Along the way, argon was discovered (1894) as an impurity in liquid nitrogen. Somewhat later, krypton and xenon were discovered (1898) during the fractional distillation of liquid argon. (Fractional distillation is accomplished by liquefying a mixture of gases, each of which has a different boiling point. When the mixture is evaporated, the gas with the highest boiling point evaporates first, followed by the gas with the second highest boiling point, and so on.)
Each of the newly discovered gases condensed at temperatures higher than the boiling point of hydrogen but lower than 173 K. The last element to be liquefied was helium gas. First discovered in 1868 in the spectrum of the Sun and later on Earth (1885), helium has the lowest boiling point of any known substance. In 1908, Dutch physicist Heike Kamerlingh Onnes (1853“1926) finally succeeded in liquefying helium at a temperature of 4.2 K.
2.1 Words to Know:
Absolute zero: The lowest temperature possible at which all molecular motion ceases. It is equal to -273°C (-459°F).
Kelvin temperature scale: A temperature scale based on absolute zero with a unit, called the Kelvin, having the same size as a Celsius degree.
Superconductivity: The ability of a material to conduct electricity without resistance. An electrical current in a superconductive ring will flow indefinitely if a low temperature (about -260°C) is maintained.
3. METHODS OF PRODUCING CRYOGENIC TEMPERATURES
Cryogenic conditions are produced by one of four basic techniques:
1. Heat conduction,
2. Evaporative cooling,
3. Cooling by rapid expansion (the Joule-Thomson effect), and
4. Adiabatic demagnetization.
The first two are well known in terms of everyday experience. The third is less well known but is commonly used in ordinary refrigeration and air conditioning units, as well as in cryogenic applications. The fourth process is used primarily in cryogenic applications and provides a means of approaching absolute zero.
3.1 HEAT CONDUCTION TECHNIQUE:
Heat conduction is a relatively simple concept to understand. When two bodies are in contact, heat flows from the body with the higher temperature to the body with a lower temperature. Conduction can occur between any and all forms of matter, whether gas, liquid, or solid. It is essential in the production of cryogenic temperatures and environments. For example, samples may be cooled to cryogenic temperatures by immersing them directly in a cryogenic liquid or by placing them in an atmosphere cooled by cryogenic refrigeration. In either case, the sample cools by conduction (or transfer) of heat to its colder surroundings.
CRYOTUBES:
Cryotubes used to store strains of bacteria at low temperature. Bacteria are placed in little holes in the beads inside the tubes and then stored in liquid nitrogen.
3.2 EVOPARATIVE COOLING TECHNIQUE:
The second process for producing cryogenic conditions is evaporative cooling. Humans are familiar with this process because it is a mechanism by which our bodies lose heat. Atoms and molecules in the gaseous state are moving faster than atoms and molecules in the liquid state. Add heat energy to the particles in a liquid and they will become gaseous. Liquid perspiration on human skin behaves in this way. Perspiration absorbs body heat, becomes a gas, and evaporates from the skin. As a result of that heat loss, the body cools down.
Cryogens and Their Boiling Points
In cryogenics, a container of liquid is allowed to evaporate. Heat from within the liquid is used to convert particles at the surface of the liquid to gas. The gas is then pumped away. More heat from the liquid converts another surface layer of particles to the gaseous state, which is also pumped away. The longer this process continues, the more heat is removed from the liquid and the lower its temperature drops. Once some given temperature is reached, pumping continues at a reduced level in order to maintain the lower temperature. This method can be used to reduce the temperature of any liquid. For example, it can be used to reduce the temperature of liquid nitrogen to its freezing point or to lower the temperature of liquid helium to approximately 1 K.
3.3 COOLING BY RAPID EXPANSION (JOULES THOMSON EFFECT):
A third process makes use of the Joule-Thomson effect, which was discovered by English physicist James Prescott Joule (1818“1889), and William Thomson, Lord Kelvin, in 1852. The Joule-Thomson effect depends on the relationship of volume (bulk or mass), pressure, and temperature in a gas. Change any one of these three variables, and at least one of the other two (or both) will also change. Joule and Thomson found, for example, that allowing a gas to expand very rapidly causes its temperature to drop dramatically. Reducing the pressure on a gas accomplishes the same effect.
To cool a gas using the Joule-Thomson effect, the gas is first pumped into a container under high pressure. The container is fitted with a valve with a very small opening. When the valve is opened, the gas escapes from the container and expands quickly. At the same time, its temperature drops. The first great success for the Joule-Thomson effect in cryogenics was achieved by Kamerlingh Onnes in 1908 when he liquefied helium.
The Joule-Thomson effect is an important part of our lives today, even though we may not be aware of it. Ordinary household refrigerators and air conditioners operate on this principle. First, a gas is pressurized and cooled to an intermediate temperature by contact with a colder gas or liquid. Then, the gas is expanded, and its temperature drops still further. The heat needed to keep this cycle operating comes from the inside of the refrigerator or the interior of a room, producing the desired cooling effect.
3.4 ADIABATIC DEMAGNETIZATION TECHNIQUE:
The fourth process for producing cryogenic temperatures uses a phenomenon known as adiabatic demagnetization. Adiabatic demagnetization makes use of special substances known as paramagnetic salts. A paramagnetic salt consists of a very large collection of particles that act like tiny (atom-sized) magnets. Normally these magnetic particles are spread out in all possible directions. As a result, the salt itself is not magnetic. That condition changes when the salt is placed between the poles of a magnet. The magnetic field of the magnet causes all the tiny magnetic particles in the salt to line up in the same direction. The salt becomes magnetic, too.
At this exact moment, however, suppose that the external magnet is taken away and the paramagnetic salt is placed within a liquid. Almost immediately, the tiny magnetic particles within the salt return to their random, every-which-way condition. To make this change, however, the particles require an input of energy. In this example, the energy is taken from the liquid into which the salt was placed. As the liquid gives up energy to the paramagnetic salt, its temperature drops.
Adiabatic demagnetization has been used to produce some of the coldest temperatures ever observedâ€within a few thousandths of a degree Kelvin of absolute zero. A related process involving the magnetization and demagnetization of atomic nuclei is known as nuclear demagnetization. With nuclear demagnetization, temperatures within a few millionths of a degree of absolute zero have been reached.
4. APPLICATIONS
4.1 INDUSTRIAL APPLICATIONS:
Cryogenic treatment works on Reamers (carbide or HSS), Tool Bits, Tool Punches (carbide or HSS), Carbide Drills, Carbide Cutters, Milling Cutters, Files, Shaping Equipment, Scissors, Razors, Clippers, Knives, Band Saw Blades, Saw Blades, Reciprocating Blades, Saber Saw, Steel Woodworking and Form Tooling, Cutting Tools and Dies. In all cases, this treatment will result a stronger and more wear resistant metal.
4.2 AUTOMOTIVE APPLICATIONS:
Imagine a racer and crew who would normally tear down their engine after every race or two, suddenly discovering a process that would allow them to safely go up to 30 races or more without a major rebuild. Cryogenic treatment of automotive parts can certainly help make this a reality.
Cryogenics works with almost all metal engine parts. Pistons, rings, rockers, push rods, connecting rods, valves, the crank and camshaft and even the block itself. Together, a treated engine can last substantially longer in terms of wear than any other process could achieve. Even parts like brake rotors, drums, and brake pads can benefit from cryogenic treatment. Really, almost any part that is normally subject to wear can benefit. Just imagine what cryogenic treatment would do for the parts in your family vehicle!
4.3 MEDICL APPPLICATIONS:
Cryogenics has also been used by the medical industry. Surgical tools used by doctors, surgeons, dentists, and other specialistâ„¢s can all benefit from the increased wear resistance of the treatment. Surgical tools, like many other industrial tools, are expensive to replace, so cryogenic treatment can really pay off.
In addition, many surgical implants are also treated. This helps prevent the part from wearing, it increases the tensile and bending strength of the part, as well as reducing the likelihood of micro fracturing. Cryogenics really is a healthy choice for the medical field.
4.4 SPACE APPLICATIONS:
Cryogenic liquids are also used in the space program. For example, cryogenic materials are used to propel rockets into space. A tank of liquid hydrogen provides the fuel to be burned and a second tank of liquid oxygen is provided for combustion. Another space application of cryogenics is the use of liquid helium to cool orbiting infrared telescopes. Infrared telescopes detect objects in space not from the light they give off but from the infrared radiation (heat) they emit. However, the operation of the telescope itself also gives off heat. What can be done to prevent the instrument from being blinded by its own heat to the infrared radiation from stars The answer is to cool parts of the telescope with liquid helium. At the temperature of liquid helium (1.8 K) the telescope can easily pick up infrared radiation of the stars, whose temperature is about 3 K.
5. ADVANTAGES AND DISADVANTAGES
ADVANTAGES:
Cryogenics can produce large quantities of high purity (parts per billion contaminations) nitrogen. Some processes like the humid-air expansion process have a yield of about 40%-60% per pass, which allows you produce large quantities of nitrogen efficiently. Other processes, like the waste expansion, have a yield of about 25-40% per pass.
Cryogenic processes do not have economics of scale, i.e., expansion or reduction of product quantity requirements generally does not necessitate new equipment.
DISADVANTAGES:
Cryogenic processes in general have very large capital cost, due mostly to the cost of compressors and turbines. The high pressure requirements and the recovery of refrigeration energy explain the need for this equipment. Cryogenic separation requires the use of not only the compressors and turbines, but also numerous heat exchangers, insulators, and a distillation column; all of which add to the high costs of the process.
6. CONCLUSION
In this seminar report titled CRYOGENICS having the methods to produce the cryogenics temperatures and many advantages which are used for industries, automotives, medical field, space crafts, etc...This seminar report has given me more experience and knowledge on the cold generation and helped me to understand what cryogenics is, how it is produced, where it has been used and what is the use of cryogenics.
