Regenerative desiccant dryers are designed to provide standard dew points of -20 °C (-25° F), -40° C/F or -70 °C (-100 °F), but that comes at a cost of purge air that will need to be utilized and accounted for within a compressed air system. There are various types of regeneration when it comes to desiccant dryers and it all depends on the amount of purge air used during the process. Higher purge will require a larger compressor, therefore resulting in increased power consumption and higher life cycle cost.
Heatless desiccant dryers require 16-25% of purge air and are considered to be most cost effective, but least efficient. When considering a heatless desiccant dryer, make sure to account for the extra purge air when sizing your air compressor. This calculation is required to sufficiently provide the required compressed air for the facility’s needs as well as the purge air necessary for the drying process.
Heated purge air desiccant dryers utilize either internal or external heaters to account for part of the bead drying process. This type of a desiccant dryer reduces the amount of purge air that is required for the tower regeneration process down to less than 10%. Due to its design and ability to cut down the purge air required in the process, this dryer requires a higher initial investment as compared to a heatless desiccant dryer, but offers a significant energy efficiency during its life cycle.
In externally heated desiccant dryers, the external purge air is heated to a higher temperature and introduced to the desiccant beads to aid with the drying and regenerating process. This type of a process utilizes on average 0-4% of purge air, making it one of the more efficient desiccant dryers. In order to eliminate the need for purge air in an externally heated desiccant dryer, a blower can be used, which would circulate the heated air throughout the desiccant bed. Due to its efficiency gains, the blower heat desiccant dryers tend to be most expensive option, but once again offer best return on your investment from the energy consumption standpoint over the lifecycle of the unit.
In conclusion, the need for a refrigerated or desiccant dryer will be mainly dependent on the specific air quality requirements for a given process. Dryers play a vital role in achieving clean and dry air that is less likely to compromise your operations and result in costly shut down or possible contamination of your product. Investing in a proper drying system now can result in substantial savings over the lifetime of the equipment and provide satisfactory products and results for your customers.
Post time: May-13-2022