liquefaction

Views:
 
Category: Education
     
 

Presentation Description

No description available.

Comments

Presentation Transcript

PowerPoint Presentation: 

WELCOME

GROUP# 06: 

GROUP# 06 M.HANIF 2010-BT-CHEM-16 M.QASIM TAHIR 2010-BT-CHEM-17 BADAR MUNIR 2010-BT-CHEM-22

LIQUEFACTION: 

LIQUEFACTION Liquefaction is physical conversion process in which we change phase of a solid or a gas to convert into a liquid state. OR A change from one state to another without a change in chemical composition.

INTRODUCTION: 

INTRODUCTION IN CHEMISTRY: The act or process of turning a gas into a liquid. Liquefaction is achieved by compression of vapors by refrigeration or by adiabatic expansion.

IN GEOLOGY: Liquefaction occurs because of the increased pore pressure and reduced effective stress between solid particles generated by the presence of liquid. It is often caused by severe shaking, especially that associated with earth quakes.

LIQUEFACTION TYPES: 

LIQUEFACTION TYPES There are different types of liquefaction. Liquefaction of soil. Liquefaction of coal. Liquefaction of gases.

LIQUIFACTION OF GASES: 

LIQUIFACTION OF GASES In simple word’s: The process of refrigerating a gas to below its critical temperature so that liquid can be formed at some suitable pressure, also below the critical pressure is known as liquefaction.

PowerPoint Presentation: 

Critical Temperature: The critical temperature of a substance is the temperature at and above which vapor of the substance cannot be liquefied, no matter how much pressure is applied. Critical Pressure: The critical pressure of a substance is the pressure required to liquefy a gas at its critical temperature.

HISTORY: 

HISTORY The first scientist to liquefy a substance is a French that produced liquid sulfur  dioxide in 1784. Most gases were not liquefied until the mid-1800s. In 1823 English chemist Michael Faraday liquefy the chlorine.

METHODS FOR LIQUEFACTION OF GAS: 

METHODS FOR LIQUEFACTION OF GAS There are two methods: Linde's method : This process is based upon Joule-Thomson effect which states that “When a gas is allowed to expand adiabatically from a region of high pressure to a region of low pressure, cooling takes place.

PowerPoint Presentation: 

Linde liquefaction process

PowerPoint Presentation: 

2. Claude's method : When a gas expand adiabatically against an external pressure, it does some external work. Since work is done by the molecules at the cost of their kinetic energy, the temperature of the gas falls causing cooling.

.: 

.

Liquefaction of soil: 

Liquefaction of soil Soft marine soils under high waves may undergo a process in which the soil grains become completely free and the water-sediment mixture, as a whole, acts like a fluid! This process is called liquefaction.

Ways of wave liquefaction: 

Ways of wave liquefaction Residual Liquefaction: Liquefaction induced by the buildup of pore pressure, called the Residual Liquefaction. 2. Momentary Liquefaction: Liquefaction induced by the upward-directed pressure gradient, called the Momentary Liquefaction.

PowerPoint Presentation: 

Residual and Momentary Liquefaction

SURFACE RUPTUR: 

SURFACE RUPTUR

What is Air? Dry air is made up of approximately 78% Nitrogen, 21% Oxygen, and 1% Argon, by volume. There are trace amounts of other stuff, like CO2, Neon, and Helium. Air also contains 1% to 4% water vapor as well : 

What is Air? Dry air is made up of approximately 78% Nitrogen, 21% Oxygen, and 1% Argon, by volume. There are trace amounts of other stuff, like CO2, Neon, and Helium. Air also contains 1% to 4% water vapor as well

Liquid air is air that has been cooled to very low temperatures so that it has condensed to a pale blue mobile liquid. To protect it from room temperature, it must be kept in a vacuum flask. Liquid air can absorb heat rapidly and revert to its gaseous state. : 

Liquid air is air that has been cooled to very low temperatures so that it has condensed to a pale blue mobile liquid. To protect it from room temperature, it must be kept in a vacuum flask. Liquid air can absorb heat rapidly and revert to its gaseous state. What is Liquid air?

Ways of liquefaction: 

Ways of liquefaction By heat exchange at constant pressure By an expansion process from which work is obtained By a throttling process

Preparation of liquid air: 

Preparation of liquid air Modern plant for air liquefaction

PowerPoint Presentation: 

The constituents of air were once known as "permanent gases" as they could not be liquefied by compression at room temperature. A compression process will raise the temperature of the gas. This heat is removed by cooling to the ambient temperature in a heat exchanger and then the gas is expanded by venting into a chamber. Due to expansion the temperature becomes low and by counter-flow heat exchange of the expanded air to the pressurized air entering the expander. With sufficient compression, flow, and heat removal eventually droplets of liquid air will form. Principle of production

PowerPoint Presentation: 

Process of manufacturing The most common process for the preparation of liquid air is the two-column linde cycle using the Joule-Thomson effect. Air is fed at high pressure at 60 psi into the lower column, in which it is separated into pure nitrogen and oxygen-rich liquid. The rich liquid and some of the nitrogen are fed as reflux into the upper column, which operates at low pressure at 10 psi, where the final separation into pure nitrogen and oxygen occurs. A raw argon product can be removed from the middle of the upper column for further purification.

DIFFERANCE B/W REFRIGRATION & LIQUEFACTION: 

DIFFERANCE B/W REFRIGRATION & LIQUEFACTION A refrigerator transfers heat energy from a low temperature reservoir to a higher temperature reservoir. Most helium refrigerators transfer heat energy from approximately 4.22K . A liquefier is different from a refrigerator since the objective is to cool a quantity (flow rate) of high (or ambient) temperature fluid to a specified low (or load) temperature.

PowerPoint Presentation: 

. 2. A refrigerator Operate as a closed loop. 3. Circulating same fluid. 4. There is no accumulation. 5. Mass Flow rate is remain same in cycle. 6. A Refrigerator can certainly make liquid coolant. 7. Vapor will return and complete the cycle. . 2. A liquefier is an open system. 3. A liquid is product is removed. 4. Accumulation take place. 5. Mass Flow rate is different in counter current system. 6. Return stream is small then stream cooled. 7. Refrigerant effect of product with drawn has been lost .

Application: 

Application Liquid air is an important source of oxygen in rockets and jet-propelled planes and bombs. The argon is useful as an oxygen-excluding shielding gas in some forms of shielded metal arc welding. Compressed helium is used in airships. Liquid carbon dioxide finds use in soda fountains. Liquid nitrogen is useful in various low-temperature applications, being nonreactive at normal temperatures. During World War Two, Nazi Germany reportedly experimented with a bomb made from liquid air and coal dust.

PowerPoint Presentation: 

Thanks The End