Imagine what compressed air is used for and write a short essay

Compressed air is the second largest power energy source after electricity, and it is a process gas source with a variety of purposes, and its application range covers petroleum, chemical industry, metallurgy, electric power, machinery, light industry, textile, automobile manufacturing, electronics, food, medicine, biochemistry, national defense, scientific research and other industries and departments. Less desirable is that compressed air contains a considerable number of impurities, mainly: solid particulates - in a typical large urban environment, there are about 140 million particles per cubic meter of atmosphere, of which about 80% are less than 2 m in size, and the air compressor suction filter is powerless to eliminate.

In addition, the air compressor system will also continuously produce abrasive chips, rust residue and oil carbide, which will accelerate the wear of gas-using equipment and lead to seal failure; Moisture - the relative humidity in the atmosphere is generally as high as 65%, after compression and condensation, it becomes moist saturated air, and entrainment of a large number of liquid water droplets, they are the root cause of corrosion of equipment, pipes and valves, and ice in winter will also block the small hole channels in the pneumatic system. It is important to note that even in pure saturated air separated from the net, condensate will still be condensate as the temperature decreases, and for every 10 decreases, the saturated water content will decrease by 50%, i.e. half of the water vapor will be converted into liquid water droplets (see Table 1).

Therefore, it is necessary to use a multi-stage separation filter device or pretreat the compressed air into dry air with a certain relative humidity in the compressed air system; Oil--Lubricating oil can be used to lubricate, seal and cool the air compressor at high speed and high temperature, but it pollutes the compressed air. Although the oil content of the compressed air is reduced, the oil content of the compressed air is reduced, the corrosion of the internal and pipeline systems of the machine, and the increase of the oil content of the air compressor during the running-in period, wear period and load reduction period. This is undoubtedly a threat to automated production lines that pursue high reliability.

It should also be emphasized that the oil brought from the compressor to the system is not beneficial under any circumstances. Because after many times of high-temperature oxidation and condensation emulsification, the performance of the oil has been greatly reduced, and it is acidic, which not only does not play a lubricating role for the follow-up equipment, but will destroy the normal lubrication; Microorganisms – Contamination by bacteria and bacteriophages in pharmaceutical, bioengineering, food manufacturing and packaging processes cannot be ignored.

With the rapid development of the national economy, compressors are widely used in the industry. Compressors are known as "general purpose machinery" because of their versatility. According to the different characteristics of the use of compressed gas, it can be divided into the following types:

1. Compressed air as power:

For driving all kinds of pneumatic machinery, the exhaust pressure of pneumatic tools is 7 8 kg square centimeters; It is used for control instruments and automation devices, and the pressure is about 6 kg square centimeter; The vehicle is automatic, the doors and windows open and close, the pressure is 2 4 kg square centimeters; agitation in the pharmaceutical industry, in the winemaking industry, with a pressure of 4 kg cm²; The weft blowing pressure in the air-jet loom is 1 2 kg square centimeter; The starting pressure of medium and large diesel engines is 25 60 kg square centimeters; fracturing of oil wells with a pressure of 150 kg cm²; "Quadratic" oil production, the pressure is about 50 kg square centimeter; The pressure of high-pressure blasting coal mining is about 800 kg square centimeter; It is powered by pressurized compressed air in the defense industry; The sinking and floating of submarines, the firing and driving of torpedoes, and the salvage of wrecks are all powered by compressed air at different pressures.

2. Compressed gas is used for refrigeration and gas separation

The gas is compressed, cooled, expanded and liquefied for artificial refrigeration (refrigeration, air conditioning, etc.) such as ammonia or freon compressors. Its compression pressure is mostly 8 12 kg square centimeters, and this type of compressor is usually called a "chiller" or "ice machine". In addition, if the liquefied gas is a mixture, each component can be separated separately in the separation device to obtain various gases that can be read by qualified lip reading.

For example, pure oxygen, pure nitrogen, and pure xenon, krypton, argon, helium and other rare gases can be obtained after air liquefaction and separation.

3. Compressed gas is used for synthesis and polymerization;

In the chemical industry, gases are compressed to high pressures, which are often beneficial for synthesis and polymerization. For example, nitrogen and hydrogen to ammonia, hydrogen and carbon dioxide to methanol, carbon dioxide and ammonia to urea, etc. In the chemical industry, for example, high-pressure polyethylene has a pressure of 1500 to 3200 kg square centimeter.

4. It is difficult to compress gas for hydrorefining of oil

In the petroleum industry, hydrogen is heated by artificial methods, and reacted with oil after pressurization, which can crack the recombinant components of hydrocarbons into light components of hydrocarbons, such as the lightening of heavy oil, hydrorefining of lubricating oil, etc.

5. Gas delivery

The compressor used to transport gas in the pipeline determines its pressure depending on the length of the pipeline. When sending remote gas, the pressure can reach 30 kg square centimeter. The bottling pressure for chlorine is 10 15 kg sq cm and the CO2 bottling pressure is 50 kg 60 sq cm.

Compressed air is very versatile. Pumping compressed air into the tires of cars and bicycles not only supports the weight of the car body and all objects on the car, but also makes the driver and cyclist feel stable and comfortable. Cars, walls and furniture can be painted with paint mixed with compressed air in cans.

Spraying unclean masonry buildings with compressed air can wipe off the dirt on the surface of the masonry. In addition, compressed air is used in many places such as hovercraft, nail guns, control of car door switches, construction, medical care, etc.

Defend against alien attacks with compressed air.

There are bicycles powered by compressed air in foreign countries.