【Q&A Question 055】February 24, 2017
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This post was last edited by 955559 on 2017-7-21 22:00 [Q&A Question No. 055] 2017.02.24 Why does compressed gas need to be cooled and separated? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) When a gas is compressed, its temperature inevitably rises; therefore, before it enters the next stage of compression, it must be cooled in a cooler to a temperature close to that at which it was drawn in. The functions of this cooling process are as follows: 1. To reduce the amount of work required for compressing the gas in the next stage, thereby lowering the compressor’s power consumption; 2. To cause oil mist and water vapor in the gas to condense, so that they can be removed in a separator; 3. To prevent the temperature of the gas after compression from becoming too high (above the flash point of the lubricating oil), thus ensuring proper lubrication of the compressor. The gas discharged from the compressor’s cylinders often contains water mist and oil mist, which condense into water droplets and oil droplets after cooling. To prevent these liquid droplets from reaching the next stage of the cylinder, it is necessary to separate them promptly. Petrochemical Zone—“Creative Ideas for Energy Savings” event: http://bbs.hcbbs.com/thread-1666758-1-1.html The New Normal Cup—voting for the top 10 members of HaiChuan in 2016 is now underway; vote for the member you care about the most (please cast your valuable vote for the members in the Petrochemical Zone). http://bbs.hcbbs.com/thread-1667649-1-1.html Summary post of Q&A questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657793-1-1.html Summary post of daily questions for 2017 (updates available now). http://bbs.hcbbs.com/thread-1657794-1-1.html Summary post of Q&A questions from 2016 (all updates completed). http://bbs.hcbbs.com/thread-1597792-1-1.html Third round of selection for outstanding management members of HaiChuan. http://bbs.hcbbs.com/thread-1655902-1-1.html Petrochemical Zone—“Creative Ideas for Energy Savings” event: http://bbs.hcbbs.com/thread-1666758-1-1.html Xiaomi phones are up for grabs. Summary post collecting chemical industry technical materials from the “Petrochemical Section”. http://bbs.hcbbs.com/thread-1654603-1-1.html Many prizes are waiting for you (Source: HaiChuan Chemical Forum)
①Reduce the work required to compress the gas in the next stage, thereby lowering the compressor’s power consumption； ②To make the entire compression process approach isothermal compression ； ③Cause the oil mist and water vapor in the gas to condense, and remove them in the separator ； ④It prevents the temperature of the gas from rising too high after compression at the next stage (so that it does not exceed the flash point of the lubricating oil), meets the performance requirements of the equipment, reduces equipment failures caused by high temperatures, and ensures proper lubrication of the compressor. The gas discharged from the compressor’s cylinders often contains water mist and oil mist, which condense into water droplets and oil droplets after cooling. To prevent these droplets from reaching the next stage of the cylinder, they must be separated promptly
During the compression of the gas in each stage, friction between the gas molecules generates heat, with the temperature reaching levels between 120 and 150 degrees; therefore, cooling is necessary. Separation mainly occurs because phase-change water is generated during the transition from high temperature to low temperature, so it is necessary to remove the moisture. Otherwise, it can cause water hammer at the later stage, leading to damage to the machine.
As the gas is compressed, the water vapor contained within it is also compressed, resulting in the compressed gas having a relatively high atmospheric dew point. When compressed gas enters a pipe at a lower temperature downstream, condensation occurs. Excessive water in compressed gas, whether in liquid or vapor form, can cause various problems for the user during operation. This includes freezing the outdoor air pipelines, which accelerates equipment corrosion and causes product contamination.
1. When a gas is compressed, its temperature necessarily rises; therefore, before it enters the next stage of compression, it must be cooled in a cooler to a temperature close to that at which it was drawn in. The purpose of this is: ① to make the entire compression process as close as possible to an isothermal compression, thereby reducing the work required for compression in the next stage and decreasing the compressor’s power consumption； ②It prevents the temperature of the gas after compression at the next stage from becoming too high (so as not to exceed the flash point of the lubricating oil), meets the performance requirements of the equipment, reduces equipment failures caused by high temperatures, and ensures proper lubrication of the compressor ； ③The gas discharged from the compressor’s cylinders often contains water mist and oil mist, which condense into water droplets and oil droplets after cooling. To prevent these droplets from reaching the next stage of the cylinder, they must be separated promptly. 2. Separation involves removing these cooled and condensed oil droplets and water droplets in a separator to achieve gas-liquid separation
V/T is a constant; when the temperature is high, fluid enters the storage tank. After cooling, the pressure drops. Therefore, it is necessary to maintain the required operating pressure in order to prevent the air compressor from starting frequently, and cooling is essential for this purpose
When gas is compressed, its temperature inevitably rises; therefore, before it enters the next stage of compression, it must be cooled in a cooler to a temperature close to that at which it was drawn in. The functions of this cooling process are as follows: ① To make the entire compression process as close as possible to an isothermal compression, thereby reducing the work required for compression in the next stage and lowering the compressor’s power consumption； ②It prevents the temperature of the gas after compression at the next stage from becoming too high (so as not to exceed the flash point of the lubricating oil), meets the performance requirements of the equipment, reduces equipment failures caused by high temperatures, and ensures proper lubrication of the compressor ； ③The gas discharged from the compressor’s cylinders often contains water mist and oil mist, which condense into water droplets and oil droplets after cooling. To prevent these droplets from reaching the next stage of the cylinder, they must be separated promptly. Separation involves removing these cooled and condensed oil droplets and water droplets in a separator to achieve gas-liquid separation
When gas is compressed, its temperature inevitably rises; therefore, it must be cooled to a temperature close to that at which it was drawn in before entering the next stage of compression. The functions of cooling are as follows: 1. To reduce the amount of work required for compression in the next stage, thereby lowering the compressor’s power consumption; 2. To cause oil mist and water vapor in the gas to condense, so that they can be removed in a separator; 3. To prevent the temperature of the gas after compression from rising too high (above the flash point of the lubricating oil), thus ensuring proper lubrication of the compressor. The gas discharged from the compressor’s cylinders often contains water mist and oil mist, which condense into water droplets and oil droplets after cooling. To prevent these liquid droplets from reaching the next stage of the cylinder, it is necessary to separate them promptly.
The gas discharged from the compressor cylinders often contains oil (as the cylinders are lubricated with oil) and water vapor, which form condensed droplets after intermediate cooling.
Gas releases heat when compressed, so cooling is necessary. High pressure and low temperature facilitate the separation of gas and liquid phases, hence liquid separation is required
When gas is compressed, its temperature inevitably rises; therefore, it must be cooled to a temperature close to that at which it was drawn in before entering the next stage of compression. The functions of cooling are as follows: 1. To reduce the amount of work required for compression in the next stage, thereby lowering the compressor’s power consumption; 2. To cause oil mist and water vapor in the gas to condense, so that they can be removed in a separator; 3. To prevent the temperature of the gas after compression from rising too high (above the flash point of the lubricating oil), thus ensuring proper lubrication of the compressor. The gas discharged from the compressor’s cylinders often contains water mist and oil mist, which condense into water droplets and oil droplets after cooling. To prevent these liquid droplets from reaching the next stage of the cylinder, it is necessary to separate them promptly.