Air dryers are frequently utilized to support daily operations in manufacturing facilities. They are also used in a variety of naval applications. No matter what kind of air compressor you have, air dryers are a must. The basic purpose of an air dryer is to remove moisture from the air. There is a lot of moisture produced by air compressors, and although some of it can be evacuated, it cannot be totally eliminated. Water is difficult to remove because it frequently lingers as an aerosol or mist.
Air Dryers are important for maintaining a dry atmosphere. Too much moisture in the air is not good for many industrial facilities. Many instruments and machines require dry air to function, and too much moisture in the air makes machines inefficient. In food industries, moist air encourages bacterial growth, and this can increase the risk of food contamination. Air compressors are also vital for preventing the corrosion of metallic components as they remove moisture from air, thus contributing to the longevity of industrial machinery.
Compressed air dryers are devices that take compressed air and extract water vapor from it. As the air cools downstream, condensation occurs because air compression concentrates water vapor.
A compressed air dryer keeps moisture from condensing by decreasing the pressure dew point below the temperature to which airlines are exposed. The pressure dew point, measured at 100 pounds per square inch gauge, is the temperature at which moisture begins to condense at a certain pressure. The lower the dew point, the more dry the air. If you want to eliminate corrosion in the air system pipes, choose a pressure dew point of -20 degrees Fahrenheit or lower.
When it comes to compressed air dryer types, there are several to choose from, and you need to be clear about your own requirements before you dive into studying the dryer specs. In many cases, an industrial facility needs multiple types of dyers. Asking the following questions can greatly help in making a more accurate choice:
• For what purpose you will use the compressed dyer
• What are the air temperature requirements?
• How much dew point pressure is suitable?
• In what environment will the air compressor function?
• At what frequency will the air compressor be operated?
Once you have a clear answer to these you will feel much more confident in making the right choice.
Desiccant dryers are known by a variety of names, such as regen dryers, pressure swing dryers, and twin tower dryers. The sucking up of moisture is done by solid desiccants like silica gel, molecular sieves, or alumina.
Desiccant dryers protect control and instrumentation systems, moisture-sensitive processes, and laboratory equipment. They're effective in applications that require the highest dew point performance, which might range from -40 to -100 degrees Fahrenheit. This low dew point prevents airline freezing even in the most severe weather conditions. Desiccant dryers should also be utilized in settings where flow rates exceed 100 standard cubic feet per minute (SCFM). There are three options for reviving the desiccant bed.
Heatless dryers use compressed air to raise the atmospheric temperature enough to dry the desiccant. Heatless dryers are safer since they do not use high temperatures or voltages. Moreover, f you have a limited budget, these dryers match well with small systems of 2000 SCFM. However, for larger systems, these dryers become quite costly. The usage life of dessicant is at least 10-15 years.
For a more powerful dessicant dryers in the range of 500-3000 SCFM internal heating dryer is the better choice. They use a different mechanism for drying out which involves the use of electrical resistance to dry out the dessicant. Since they use a complex mechanism they cost significantly more than heatless dryers. The usage life of dessicant in internal heating dryers is also shorter and the dessicant should be replaced within three to five years.
For a dew point range of 20 to 60 degrees Farenheit membrane dryers are ideal. The drying efficiency of the membrane depends on pressure controls and flow rate. The advantage of this dryer is that they operate silently as they have no moving parts. Moreover the maintenance cost of these dryers is also low and only the replacement of a pre-filter cartridge twice a year is required. These dryers hit a dew point range of 35 degree Fahrenheit to 52 degree Fahrenheit.
Having a compressed air dryer that is hassle-free and easy to maintain is can be really useful if you prefer less hassle. Point of use dryers deliver just that as they are capable of a dew point range of -40 degrees to 100 degrees Fahrenheit. They can also run for long duration of 12000 hours between dessicant replacement. For maintenance the re-filter cartridge replacement is enough.
Refrigerated dryers are the most popular type of dryer. They work by condensing water in a heat exchanger, cooling the air sufficiently to condense the entrained moisture, and removing it from the air supply. The cold, segregated air is then reheated and removed from the system.
Refrigerant dryers maintain a steady dew point range of 38 to 50 degrees Fahrenheit despite fluctuations in inlet temperature. They cannot achieve dew points below freezing. When using such a dryer in a polluted area, it is best to use a water-cooled condenser.
Refrigated dryers are ideal for intensive usage and can operate continually at full capacity. So using them at a low frequency can actually damage them. For lower usage equirement cycle type refrigated dryers are a more suitable choice as they use less power and are energy efficient.
Deliquescent dryers employ tablets to attract moisture before dissolving them. They create a dew point range of 40 to 80 degrees Fahrenheit, which is precisely proportional to the input-air temperature, as they lower the dew point by a predetermined amount below the inlet temperature. Operating costs are exactly proportionate to air consumption, with no desiccant required when there is no air demand. However, deliquescent dryers must be refilled with deliquescent tablets on a daily basis. Such dryers are not as frequently used.
Assess the maximum capacity of the air compression system as the air dryer should match your requirements. Calculating capacity consists of multiplying air compression horsepower dryer spec by the number four. It can also be determined by checking SCFM at 100 PSIG.
Another dryer spec to look at before purchasing it is operating pressure. The lowest pressure rating for dryer starts from 100 PSIG and with every 100 increase in PSIG, the capacity is reduced. As a rule as the pressure increases the workload on compression system also falls.
You should also consider the minimum and maximum operational air inlet temperatures for your system when determining the dew point requirements. The ideal dryer type will meet those requirements by operating efficiently at a dew point temperature lower than the lowest ambient temperature to which the compressed air system may be exposed. To determine the required dew point temperature, subtract 20 degrees from the lowest air temperature. While chilled dryers are adequate for most applications, essential applications needing minimal moisture in the air line may necessitate a desiccant dryer.
By knowing your system's minimum and maximum operational ambient air temperatures, you should be able to pick between a low-temperature dryer and a high-temperature dryer. Ambient temperatures above 100 degrees Fahrenheit may surpass your dryer's maximum inlet temperature. Consider larger or high-temperature driers, which can handle higher ambient temperatures in the summer months.
The ideal pressure dew point for your air system is lower than the lowest ambient temperature in your facility. If not, moisture will condensate in the air lines. Consider if air lines are exposed to external temperatures throughout the summer and winter, or if they are routed through air-conditioned areas.
Lastly, after you have studied the specs make sure to do a review check of the brand you are buying from as there can be a significant difference in quality between various dryer brands.
