Dessicant Specifications

[Wizard74]

Hi,

I'm in the process of procuring an air drying dessicant.
The dessicant is housed in two towers which is sequenced to alternate to dry the incoming compressed air.
The dessicant used is activated alumina.

My process requirements:
Airflow: 1000 m3/hr
Incoming dew point: 29 degC (tropical atmospheric)
Target dew point: -30 degC

I wish to ask if there is a typical performance data (of the dessicant material) the vendor should have / I should ask, to ensure that dessicant material performs to requirements.

Thanks in advance.

 

[Montemayor]

Wizard74 (Chemical):

You're going about this the wrong way.

Your adsorption dryer was designed to operate with a specific adsorbent by the designer/fabricator of your unit. This adsorbent was picked taking in consideration a variety of factors:

1) the outlet dewpoint required;
2) the process temperature and pressure;
3) the nature of the gas being dryed;
4) the length of the drying time (cycle);
5) the type of regeneration being applied, the max. regen temperature, and the regen gas used;

There are other parameters, but the above suffice to explain to you that you may not be free to select the adsorbent that you like, prefer, or being sold by others.

I would advise you to stick with your dryer's fabricator/designer and use what he has prescribed for your application. If you desire a change in outlet dewpoint, for example, consult with him as well on a possible adsorbent upgrade. However, be prepared to make other changes as well - such as cycle times, regen temperatures, and regen gas rates.

I know that there are common situations (like instrument air) where you can vary the adsorbent and not make a significant change in the operating conditions and results. However, I have had to assume that you are describing a process dryer that is critical in your plant and I must assume you would not take a risk nor would like to experiment with your investment.


Art Montemayor
Spring, TX

 

[TomOC]

You can ask for typical performance data (of the dessicant material) from activated alumina vendors. Specifically you should ask for isotherms, to ensure that dessicant material performs to requirements.