The damage of compressed air moisture content is too high and the solution

Compressed air with water can continuous production, brings the serious influence to the enterprise in order to guarantee the normal production and transportation of compressed air, meet the production needs, how to remove the moisture in the compressed air?

Compressed air with water to produce the harm caused

In the manufacturing process of compressed air, the temperature is often go down. Because air compressor at the beginning of the heating temperature is higher, the air moisture evaporation. Heat transfer in pipe flow in the surrounding environment, can make the compressed air to cool down slowly. The lower temperature (ambient air temperature), water vapour in the compressed air condensing the easier it is to happen. When released from outfalls in the use of compressed air, pressure plummeted, volume expansion, the temperature is reduced, can cause further condensing water vapor in the compressed air into water.

Effects of the water in the compressed air is mainly manifested in: condensate oil will be taken on pneumatic equipment, which reduces the equipment efficiency and even damaged. Condensate will accelerate in pipeline valve wear and pneumatic control equipment failure or incorrect operation; Corrosion in the pipeline and equipment, if the water freezes in the low point of the line, pipeline and explosion danger. Such as spraying with compressed air contains water mist, will affect coating adhesion on artifacts, lead to coating failure.

Compressed air with water can be caused by a variety of reasons, both the process design is not reasonable cause, there are also the cause of the improper operation; Both the structure of the device itself, and the technology level of equipment and control components.

High moisture in compressed air directly affects the air pipe and the use of compressed air equipment, how to let air compressor output of compressed air moisture content reached a nadir?

As is known to all, our breathing is the atmosphere contains water, only the moisture content will change because of the weather and environmental reasons. Dry environment is much lower than the water content of the compressed air under high humidity air, the water content of the environment as a factor here. Air compressor’s own gasholder and external storage tanks as compressed air storage device, such as storage is most of the compressed air, but can contain a small amount of water in the compressed air and oil and other substances. Compressed air moisture content high, therefore, one of the reasons is that use how long can discharge air tank in the water at a time. Such as long time no emissions, water stored up too much in the store jar, compressed air moisture content will be increased accordingly.

Compressed air moisture content is too high and one of the most important reason, post-processing equipment, precision oil mist filter, freeze dryer, adsorption dryer, such as drainage device failure. These devices to the main role is to filter the composition such as moisture in the compressed air, oil, make the compressed air becomes pure and without impurities.

Such as pharmaceutical factory, toy factory, the higher requirements for compressed air manufacturers such as what need compressed air for deodorant, disinfection process to use. Back to the air compressor post-processing equipment, the difference is, and did not install the equipment installed under the normal temperature without compressed air post-processing equipment installed the water content of from 20% to 20%, and the post-processing equipment installed after the compressed air moisture content to 0.01% ~ 0.01%. Using good quality equipment, water content down to a lower or achieve high standards of dry compressed air. Such as low requirements for compressed air, air compressor use 10 hours a day on average, suggested that the average every three days or so to discharge a storage tank, the precision of the water in the oil mist filter, which can reduce the water content of compressed air. Such as use 24 hours a day, it is recommended that the emissions once a day; Also can install drainer equipment such as automatic discharge water, air compressor maintenance on a regular basis can also reduce water content!

The compressed air with water and the analysis of the causes of the several solutions

Screw air compressor itself with water removal equipment, generally at the exit of the machine, can be to remove part of the water, into the post-processing equipment in addition to water, oil removal and dust removal filter can remove part of the water, but most mainly by drying equipment drying machine to remove moisture, make through its clean compressed air drying and then sent to the gas pipeline. Many enterprise users using micro thermal regeneration towers adsorption dryer, but use the dryer also can’t ensure that compressed air is no longer have water precipitation, combined with some actual situation under the analyse the compressed air after drying machine in addition to the water is not entirely a variety of reasons and solutions.

1, the cooler of air compressor cooling fin is plugged, dust and other compressed air cooling is not good, dew point pressure, will give post-processing equipment in addition to the water to increase the difficulty and especially in the spring, cooler of air compressor are frequently catkin jam.

Solution: install filters in the air compressor station window sponge, and often to the cooler blowing, ensure good for compressed air cooling; In addition to the normal water guarantee itself.

2, the water removal equipment of screw air compressor fault - steam separator. If air compressor adopts cyclone separator, inside the cyclone separator adding spiral baffle to enhance separation effect (also increases the pressure drop). The shortcomings of the separator is its separation efficiency at the rated capacity is higher, once deviated from its separation efficiency is more bad, cause dew point rise.

Solution: check gas water separator, such as congestion problems timely processing, if found in summer air humidity larger gas water separator undrained, should immediately check processing.

3, process of compressed air consumption, beyond the scope of design, the compressed air in air compressor station and client pressure difference is bigger, lead to high air velocity, compressed air and adsorbent contact time is short, and uneven distribution of inside the dryer, in the central flow concentration, make the middle part of the adsorbent too saturated, adsorbent can not effective after saturated adsorption of moisture in the compressed air, compressed air entrained moisture from the central focus, through the in great quantities, produce "tunneling", causes a large amount of liquid gas. In addition, the compressed air to low voltage side in the process of conveying adsorption type dry too fast, the pressure to reduce rapidly, at the same time lower the temperature is larger, lower than the dew point pressure, the water vapor in the supersaturated state precipitation, winter will soon in the pipeline solidification hanging on the wall of ice, ice thicker, finally the pipe may be blocked.

The solution: to increase the flow of compressed air. The extra added wind instrument technology can be the wind, in the process air drying machine front access wind instrument, valve control, solve the problem of process using compressed air supply is insufficient, at the same time, also solved the compressed air in the dryer adsorption tower "tunneling" problems.

4, adsorption dryer used for activated alumina adsorption material, the filling is not closely will be under the strong impact of compressed air, leading to the friction and collision pulverization, pulverization can make adsorbent gap is more and more big, a lot of compressed air from the void by has not been effective processing, eventually led to the failure of drier and the problems in the field as proof for dust removal filter contains a large amount of liquid water and plasma phenomenon.

Solution: filled with activated alumina closely filled as much as possible, use for a period of time after inspection, the added.

5, compressed air with oil can lead to activated alumina by oil poisoning them. Screw air compressor used in super cooling agents with high thermal conductivity, used for cooling the compressed air, but it do not completely with compressed air separation, makes out the air compressor oil with compressed air, compressed air of the oil will be attached to the surface of activated alumina ceramic ball, jam the wool stoma of activated alumina, lose activated alumina adsorption capacity and the oil poisoning, loss of moisture adsorption function.

Solution: replace the oil separator core on time, after oil removal filter, guarantee the rear air compressor oil and gas separation thoroughly, in addition to the oil filter oil removal is good, in addition, the unit within the super cooling agent shall not be excessive.

6, air humidity is big, the frequency and timing of the drain valve drainage drainage time adjustment, not in time can make more and more water in the filter, the compressed air in the water again.

The solution: timing drain valve discharge frequency and time can be set according to the humidity of the air and experience. Air humidity is big, should increase the discharge frequency, at the same time increase the drainage time, adjust the standard for observing each drainage can just put the water discharge without compressed air. In addition, the transfer line with insulation, steam tracing; At the low point drain valve, regular check, drainage, by this measure can prevent winter freezing tube, and can remove part of the water from compressed air and mitigate the effects of compressed air with water to the user. Analyzes reason of compressed air and water, and take corresponding measures to solve above.

Compressed air moisture formula

In wet air, the weight of 1 kg dry air containing water vapor is called "moisture content, often use d to, said units: g/kg of dry air. Moisture content of the formula is:

D = 622, Ps/(P - Ps)

or

D = 622 · phi Psb/(P - phi Psb)

Type: P - air pressure (Pa), Ps - water vapor partial pressure (Pa), Psb - saturation vapor pressure (Pa), phi - relative humidity (%).

Can be seen from the type, the moisture content d almost as water vapor partial pressure is directly proportional to the Ps, and is inversely proportional to the total air pressure P. D reflects exactly how much the amount of water vapor in the air. Because in a certain area, the atmospheric pressure is basically a fixed value, so the air moisture content is only related to water vapor partial pressure Ps.

As the pressure P increase, saturated moisture content will be reduced in the air. The relative humidity of compressed air phi phi ’and the actual water content’ s determined by the type:

From ’= (Pb, P)/(Pb, P)

or

Rho = phi, ’rho, b (kg/m3)

Type: P P ’- compressed air before and after the absolute pressure (Pa)

Pb Pb ’- before and after compression and the respective temperature saturation vapor pressure (Pa)

Phi - compressed air relative humidity (%) of the phi ’compressed air relative humidity (%)

Rho b - compressed with the temperature corresponding to the saturated vapor density (g/m3)

If phi ’= 100%, the compressed air in the saturated state. The saturated vapor pressure of compressed air:

Pb = phi (Pb · P ’)/P (Pa)

Can be used to determine the type of atmospheric pressure dew point pressure of compressed air dew point and the corresponding conversion relation.