Why Heat Reactivated Desiccant Dryers Should Be Paired with High Temperature Dust Filters
Posted on November 22nd, 2021
If you are manufacturing or installing a heat reactivated desiccant dryer, you should also consider installing a specialized dust filter capable of handling higher-than-normal temperatures. Heat reactivated desiccant dryers can run a risk of producing temperature spikes during tower changeover.
Over time, these spikes can damage or reduce the life of standard dust filters. Additionally, in the event of a control system failure, heat reactivated dryers may allow high temperatures to pass downstream, potentially damaging normal dust filters. By pairing a high temperature dust filter to the dryer’s outlet, you can protect your system and company from the consequences of high temperature spikes or surges.
Heat reactivated dryers can also accelerate desiccant aging, resulting in increased downstream particulate loads. The dust filter must remain in serviceable condition to ensure that desiccant dust does not pass downstream.
How Does a Heat Reactivated Desiccant Dryer Work?
Heat reactivated desiccant dryers use the process of adsorption to remove moisture from a compressed air system. Like a heatless desiccant dryer, the adsorption process directs the airflow over a desiccant bed. However, heat reactivated dryers apply heat to the purge air during regeneration as the air passes through the off-stream desiccant bed to remove the accumulated moisture more efficiently.
Heat reactivated dryers can significantly decrease the amount of purge loss required to regenerate the desiccant beds compared to heatless regenerative dryers. However, the increase in adsorption efficiency is partially offset by the cost of the electricity to run the heater. Nevertheless, older systems that struggle for capacity can see increased efficiency with a heat reactivated dryer because the purge loss of a heat reactivated desiccant dryer is typically at least half of a heatless regenerative dryers.
What is a High Temperature Desiccant Dust Filter?
The average compressed air filter is not constructed with materials suitable for elevated temperatures. Standard compressed air dust filters are only designed for 120˚C (248˚F). A high temperature desiccant dust filter is designed with materials appropriate to allow it to be installed on a heat reactivated desiccant dryer’s outlet.
The dust filter is specially manufactured to withstand temperatures up to 232˚C (450˚F). While it is not typical for the compressed air to reach 232˚C, control system failures are possible and can be catastrophic. Therefore, installing a high temperature desiccant dust filter is usually a small price to pay for peace of mind that damage would be minimized in the rare event of a failure.
The Risks of Not Pairing a Heat Reactivated Desiccant Dryer with a High Temperature Desiccant Dust Filter
Most of the time, the outlet temperature from a heat reactivated desiccant dryer should not be excessive, but malfunctions are possible and can cause severe liabilities, including:
- Filter housings melting or exploding
- Compressed air contamination
- Damage to other compressed air treatment equipment
- Damage to end product
A regular filter housing cannot withstand excessive heat, especially over long periods. Not using a high temperature dust filter on the dryer’s outlet risks the housing failing due to the increased temperature. Anytime a housing fails, the compressed air’s quality is compromised, impacting the entire system and potentially even the end product. Therefore, a housing that can withstand system temperatures as high as 450˚F is ideal and provides extra insurance against possible liabilities.
The Walker Filtration High Temperature Dust Filter
Every compressed air system is unique, but some factors remain the same. When picking the best dust filter range to pair with your system, it is crucial to ensure adequate pressure and temperature ratings, a wide range of connection sizes and high-quality filter elements. Typically, high temperature filters are provided in either carbon or stainless steel. The material does not affect performance, so that an aluminium version can be a more cost-effective option.
At Walker Filtration, we always recommend our customers equip their heat reactivated compressed air dryers with a high temperature dust filter. We want to ensure you have not only the driest air but also the cleanest. Our high temperature desiccant dust filter is a one-of-a-kind product. Not only is the housing the only one that offers cost savings by being made of aluminium, but our team can work with you to create custom-built solutions that fit seamlessly into your dryer package.