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Compressed air treatment equipment is often referred to as refrigerated dryer, compressed air filters, air storage tanks. As we all know, the air compressed by the screw air compressor can not be used directly, because it contains a lot of moisture, oil and other pollutants, so it is generally matched with compressed air treatment equipment, and its role is to filter the impurities in the compressed air. If the compressed air is used directly without air treatment equipment, the following hazards will occur:1, solid impurities: impurities less than 2μm in diameter, can not be filtered out. The unit will also constantly produce dust, rust slag and oil carbide, will accelerate the wear of gas equipment, leading to seal failure;2, moisture: compressed air contains a lot of moisture, will rust equipment, pipes and valves. Under the condition of low temperature in winter, it is easy to freeze and block the orifice passage in pneumatic system. Even if the separation of clean pure saturated air, with the reduction of temperature, there will still be condensed water analysis report.3. Oil: the oil in the compressed air mainly comes from lubricating oil. During the operation of the unit, part of the lubricating oil will enter the compressed air and make it polluted. Although the use of oil-free machine reduces the oil content in the compressed air of screw air compressor, it also produces side effects such as reduced life of wearing parts, corrosion of the machine internal and pipeline system, which is undoubtedly a threat to the pursuit of high reliability of automatic production line and gas equipment. To sum up, we can see the importance of post-processing equipment. So how to choose the rightCompressed air treatment equipment is often referred to as refrigerated dryer, compressed air filters, gas storage tanks. As we all know, the gas compressed by the screw air compressor can not be used directly, because it contains a lot of moisture, oil and other pollutants, so it is generally matched with post-processing equipment, and its role is to filter the impurities in the compressed air. If the compressed gas is used directly without post-treatment equipment, the following hazards will occur:?Compressed air dryer: the dryer removes moisture and oil from the air compressor. At present, there are two kinds of compressed air dryers on the market: adsorption and refrigerated type. For general manufacturing enterprises, it is OK to choose refrigerated dryer, but for some enterprises with high requirements on the dryness of compressed gas, it is recommended to choose adsorption dryer.Air storage tank: the main function of gas storage tank is buffer, cooling, water, oil. When the air passes through the tank, the high-speed airflow hits the tank wall to produce confluence, which makes the temperature drop rapidly in the tank and liquefied a large amount of water vapor, thus removing a large amount of water and oil. The gas storage tank can be purchased by regular manufacturers.The role of the compressed air filter: compressed air in addition to water, oil, and dust and a variety of odor components, with physical methods to remove these compressed air pollutants equipment called filter. The higher the general series, the higher the filtration accuracy. It can be configured according to the level of compressed air quality requirements of the screw air compressor.

Applicable to the occasions of adsorption dryer: compressed air water grade is divided into 6 levels, of which 1~3 pressure dew point are below -20℃, must use adsorption dryer to achieve. Its typical applications include photographic film, microelectronic chip (level 1, -70℃), precision spraying (Level 2, -40℃), powdery product delivery (level 3, -20℃), etc. Although some occasions to the dew point of compressed air is not very strict, but gas pipeline through below 0 ℃ environment and external thermal insulation material, no in order to prevent the transmission of residual moisture in the compressed air in the pipe frozen, it must make its dew point pressure is lower than environment can achieve low temperature, this is also adsorption of compressed air dryer shall apply in addition to water treatment. The air dew point processed by the adsorption dryer can cover the treatment effect of the freeze dryer, so in principle all occasions using the freeze dryer can be replaced by the dryer, but the other way around is not ok. Because the energy consumption of the freeze dryer is much lower than that of the adsorption dryer, it is definitely not economical to replace the freeze dryer with the adsorption dryer.Selection of regeneration mode: dew point of finished product and regeneration energy consumption are two major factors that must be considered when choosing adsorption dryer. Generally speaking, both can not be taken into account, that is, to obtain low dew point compressed air, it must pay more energy consumption. According to the adsorption theory, the basic form of adsorption dryer only has two kinds of thermal regeneration and thermal regeneration. No heat regenerative dryer because on the basis of pressure swing adsorption, used the short cycle of work, by its handling of the compressed air dew point both in depth and stability is better than a heat regenerative dryer, and renewable energy has been very close to the theory of the bottom line, so since there is no heat regenerative adsorption dryer, heat regenerative dryer will have a tendency to exit the application.Selection of adsorbent: activated alumina and molecular sieve are commonly used adsorbent adsorption dryer. Both of these adsorbents have strong adsorption capacity for water vapor. Activated alumina also has a lot of excellent physical and chemical properties, so in most occasions is the choice of adsorption dryer. Especially in the case of no thermal regeneration, activated alumina is almost the natural choice for obtaining compressed air at the pressure dew point of -40℃. However, the adsorption capacity of the adsorbent in low moisture environment is far less than molecular sieve, so molecular sieve will be very useful in obtaining extremely dry compressed air (pressure dew point below -60℃). But the mechanical strength and anti-droplet performance of molecular sieve is not ideal, so it is often combined with alumina to obtain a better effect. It is not the best way to choose molecular sieve as desiccant in all occasions.Selection of combined dryer: a freeze-drying base preprocessing in the upstream of adsorption dryer is a good process design to obtain extremely low dew point compressed air and reduce the regenerator. It is generally believed that the savings in energy costs over the lifetime of this combined application will more than offset the increased initial investment in equipment. When the operation quality of compressed air system is higher, the cascade arrangement can be selected. The rigid assembly of two different types of drying equipment together to form a so-called "modular dryer" is not necessary in most cases. A good air source system should not only provide better working conditions for each equipment in the system to play its greater effectiveness, but also take into account the convenience of daily maintenance and troubleshooting of equipment. From both points of view, the split cascade seems to be better than the "combined dryer".

Maintenance of compressed air treatment equipment1. Daily maintenance: after use every day, it is necessary to check the oil level, exhaust temperature, exhaust pressure and other aspects of the screw air compressor to see if there is any abnormality. If the oil level is too low, it is necessary to add lubricating oil in time. In addition, you also need to check whether the machine has abnormal sound.2, regular maintenance: routine maintenance can prevent in the future, in addition to the use of a period of time to do regular maintenance is also indispensable. Regular and appropriate inspection and replacement of maintenance accessories, can be - air compressor with good quality operation. Generally, an inspection should be done after 300 hours of operation, and the frequency of inspection should be determined according to the use situation. Check accessories and cables regularly, replace immediately if damaged. In addition, keep the filter clean can avoid a lot of equipment failure, unclean filter will reduce the performance of the compressor and the service life of the compressor. Clean the filter in time, keep the machine clean and dry, not stained with oil, so as to give full play to its performance.3, standard voltage: the safe use of air compressor is the premise of air compressor maintenance, especially for voltage, should be strictly in accordance with the voltage, frequency and rated load of air compressor calibration, compressed air post-processing equipment, so that the effect will be --, and the user will be safer for the machine. Pay attention to keep the power supply voltage consistent with the voltage identified on the nameplate of the air compressor, too high may cause personal accidents and damage to the air compressor, too low will also cause the start -- or even damage the motor.4. Use environment: the ambient temperature of the air compressor should be kept at 5-40 ℃. The compressed air post-processing equipment in Shanghai can not be placed in a place without shelter, and do not work in a place where liquid gas and volatile gas are stored. Keep your environment clean and tidy to avoid accidents. When the air compressor is not in use, the air in the storage tank should be discharged, the sewage in the storage tank should be discharged, and stored in a dry environment.5. Regular sewage discharge: Air compressor works in places with more dust particles for a long time, which is easy to produce dirt. Therefore, the sewage in the air compressor storage tank should be discharged clean in time. It is recommended to discharge it at least once a week, which can be determined according to the working environment.6, habits; For example, when you go off work, you do not need to use the air compressor, and you should cut off the power supply in time. If the air compressor equipment fails, do not operate blindly. The air compressor maintenance personnel or the old master of air compressor maintenance should operate under the guidance of the operation. Before operation, the air compressor mechanical and electrical source should also be disconnected.

How to maintain compressed air adsorption dryer Compressed air adsorption dryer is an important equipment for users to provide clean compressed air. It has various types, which can be divided into heatless adsorption dryer, heated adsorption dryer,blower heated adsorption dryer,heat of  compression adsorption dryer and so on.When the compressed air adsorption dryer is first used or stopped for a long time, it should pay attention to the following points:1.  at the early stage of use, the adsorbent (mostly alumina) is still in natural wet condition, and it needs to gradually establish adsorption activity through repeated "regeneration purge";2.  After using the compressed air adsorption dryer for a period of time, under the effect of alternating pressure, the bulk density (filling tightness) of the adsorbent may increase, and the adsorbent needs to be increased according to the situation;3. The muffler is one of the vulnerable parts in the compressed air adsorption dryer. It should be protected regularly and can be used to remove all kinds of impurities attached to the surface by low-pressure gas blowback4. for the heating dryer, the opening of the throttle valve should be adjusted according to the discharge temperature of the gas instead of the inlet temperature;5.  Whether the filter equipment is complete affects the long-term operation and exhaust quality of the compressed air adsorption dryer;6. Users should use according to the nameplate rules of compressed air adsorption dryer, and all parameters should be within the scope of additional permission;7.  to adjust the throttle valve opening according to the dew point condition, so that the gas consumption to reach smaller.

The oil content of the air in the intake tower should be controlled below 0.01PPM. In view of the fact that some oil-free air compressors cannot be truly oil-free, it is necessary to install an oil-removing filter at the air inlet of the dryer in order to prevent the accumulation of trace oil in the adsorption bed (such accumulation is very fast).The adsorption dryer shall be used under the condition of rated temperature and pressure. When the inlet air temperature is higher than or the inlet air pressure is lower than the rated value, the capacity shall be modified.When the adsorption dryer and piston air compressor are used together, the stabilized air storage tank should be set in front to eliminate the high-speed impact of pulsating air flow on the adsorbent;When there is a freeze dryer in front, the connection between the adsorption dryer and the freeze dryer should be installed separately as far as possible as long as the site permits, in order to reduce the air pressure drop, improve the ventilation conditions of the freeze dryer and facilitate daily maintenance and repair; When the gas supply is sufficient, the regenerative dryer without heat can be listed as the first choice, and its dew point is lower and more stable.

The consumable parts of desiccant dryers are adsorbent, valve and muffler. As the industrial main body of the dryer, the adsorbent is subjected to the frequent impact of pressure, water vapor and heat in most of the time, which is easy to be broken mechanically and contaminated by the medium, so that the performance of the adsorbent is degraded. Since the activated alumina after replace silica gel as select adsorbent, all sorts of performance are greatly improved, especially the compressive strength and resistance to liquid water soaking performance reached a high level, as long as it doesn't appear operating factors, such as "renewable energy deficiency" by activated alumina, the compressed air dew point stability reached to 40 ℃ in technology, and life can be more than 2 to 3 years.Control valve is easy to damage parts in adsorption dryer. Frequent switching and long-term exposure to water and adsorbent stripping are important reasons for valve damage.Muffler is more prone to failure of the components, its main form is muffler exhaust channel blockage. Once the muffler failure (blockage), the damage to the machine is fatal, will lead to adsorbent regeneration performance decline, premature aging. Therefore, silencer is the focus of daily maintenance of desiccant dryer.

The general working principle of adsorption dryer is very simple: moist air flows through hypersonic materials (usually silica gel, molecular sieve, activated alumina), here to be dried. Water vapor is transferred from moist compressed air to hygroscopic materials or "adsorbents". This process saturates the adsorbent with water, so the adsorbent must be periodically regenerated to restore its drying capacity. There are four different methods of desiccant regeneration, which determine the type of adsorption dryer. 1. Pressure swing adsorption regeneration dryer (also called no heat regeneration adsorption dryer) : this dryer  is suitable for small air flow. The regeneration process requires the help of expanded compressed air. The dryer consumes 15 to 20% of the rated air at a working pressure of 7bar.2. Heating regenerative adsorption dryer: the dryer uses an electric heater to heat the expanded compressed air, so the required air consumption is limited to 8%. This dryer saves 25% energy compared to no heat regenerative dryer.3. Blower regeneration adsorption dryer: the surrounding air blows through the electric heater and contacts with the wet adsorbent, so that the adsorbent regeneration. This type of dryer does not use compressed air to regenerate adsorbent, so energy consumption is more than 40% energy saving than no heat regenerative dryer.4. Compression heat regeneration adsorption dryer: the adsorbent in the compression heat regeneration dryer is regenerated by using compression heat. The regenerative heat is not eliminated from the rear cooler, but is used to regenerate the adsorbent. This type of dryer can provide a pressure dew point of -20 ° C without any energy input. Lower pressure dew points can also be obtained by adding additional heaters.Therefore, the blower regeneration adsorption dryer and compression heat regeneration adsorption dryer, also known as zero gas consumption adsorption dryer. Because compared with traditional adsorption dryers, these two types of dryers do not use compressed air to regenerate adsorbent, energy consumption is more energy saving than non-thermal micro-thermal regenerative dryers.