Desiccant Air Dryers 3

[ProcessRookie]

Does anyone know of any good design guides for designing desiccant air dryers?

We are doing some pipework repair around an instrument air dryer and I am looking at the job from the process point of view.

My main aim is to size the regeneration inlet orifice required. To do this I need to understand how the dryer was designed. The problem is the unit is very old and there is no vendor or design information on it, I am just going off of PSV set pressures and TI readings. I know that it is an alumina desiccant adsorption medium which is used, that steam heating is provided for the regeneration process and that the outlet pressure for regeneration is atmospheric.

Any help much appreciated.

 

[Montemayor]

ProcessRookie (Chemical)

Your query is how to arrive at the required flow rate of regeneration gas required to carry out the regeneration of one of the adsorbent beds in your air dryer unit. Am I correct?

In order to do that, you have to identify the following:
• The size of the adsorbent bed, lbs;
• The amount of steel subjected to heating up the equipment while regenerating the bed;
• The type of regeneration cycle;
• The regeneration gas used;
• The heat up cycle time available for heating up the bed.

I did this many times in my career and to show you how I did it, step-by-step, I am attaching a copy of the calculations I saved of one project I did a long time ago (46 years). This should suffice to show you one way to do it. You’ll be using steam instead of an electric heating element, but that should not be a problem. You have to calculate the weight of all the steel heated up, but again that should not be a problem.

I hope this helps you out.

 

[ProcessRookie]

Montemayor, thanks you very much. Very helpful.