The rate of air humidity is one of the determining conditions at the factories of such industries as construction, chemical, food, pharmaceutical industry, mechanical engineering and many others. The degree of humidity can largely determine the quality of the manufactured products and materials. Also, often maintaining a certain level of humidity becomes a factor in increasing or decreasing costs. An apparatus such as an adsorption dryer is used to regulate this parameter.
Typically, such a device is used in various enterprises to maintain the desired level of humidity in the production of hygroscopic raw materials, wood, textiles, for long-term storage of grain.
Description of the device
According to its structure, the desiccant of the adsorption type looks like two columns or towers installed perpendicularly on the bed or supports. Both rows of the device are filled with adsorbent and equipped with electronic control with a display, through which you can set different modes of operation of the desiccant. At the outlet and inlet of the adsorption device mounted compressed air filters.
Principle of operation
The feature of the operation of the installation is as follows. Compressed air enters one of the columns, which is contained in the adsorption dryer, and the adsorbent (it fills the tower) absorbs all excess moisture. The dried air goes further along the pneumatic lines to the consumer.
Often, such a device works on a timer, and after a certain period (on average, it is 4 hours), the tower, through which the compressed air penetrates, switches to the function of removing moisture from the adsorbent. When the first column enters the regeneration, the second one overlaps and begins to pass air through it. Then the cycle repeats.
Cold Recovery Adsorption Devices
The principle of their operation is to delay the moisture in the outer layers of the seeds of the adsorbent and its further removal to the outside by cleaning it with a portion of the already dried air. Such an adsorption dryer has several advantages in comparison with hot regeneration equipment: simplicity of structure and low power consumption.
The downside is the loss of compressed air during the resumption of the adsorbent, which is up to 15% of the finished gas mass. This factor should be considered for the correct choice of compressor. That is, the required productivity should be selected taking into account the fact that part of the dry air will be spent on ensuring the functioning of the apparatus.
Installations with hot closed adsorbent regeneration
To restore it, a portion of dry air is taken, heated with the help of heating installations installed in it. A part of the dried gas is also taken in to cool the element. Such an adsorption compressed air dryer has neither a vacuum pump nor a blower. It is used when, for some reason, it is impossible to apply air, and in other unusual cases. The waste of compressed gas is about 5%.
Desiccants with hot outdoor renewal of the adsorbent
The air for regeneration is drawn from the atmosphere by means of a blower, which creates a slight excess pressure, and is heated by external heating components before entering the adsorber. After cooling, air is similarly taken to cool it, but after cooling is completed, a portion of dried compressed gas is applied, which creates losses that are approximately 2-2.5%.
Closed Circuit Devices
Such an adsorption air dryer uses to regenerate the adsorbent heat generated during compression of atmospheric gas by the compressor. To regenerate the element, compressed air is taken from the condenser of the final stage of compression, which as a result is cooled in the built-in water regenerator and sent for dehumidification.
To cool the adsorbent, compressed gas is taken, which then returns to the compressed air system. Cooling and heating are carried out at current pressure. The costs of compacted air and the expenditure of electricity for the functioning of a dehumidifier of this variety are absent.
Equipment with a warm recovery under vacuum
An adsorption dryer of this type for the regeneration of the adsorbent takes the air, which is sucked into the element through a pressure less than atmospheric with the aid of a vacuum pump through the external heating parts. Features of vacuum drainage make it possible to use only air for cooling. Loss of compressed gas with the use of installations of this type is not detected.