4 replies to this topic

[manish malviya]

We have a cryogenic oxygen plant and designed flow rate is 31500 nm3/hr.I want to know how to calculate the moisture contents in the compressed air.

and also i want to know how to calculate the capacity of MSA bed.

[Art Montemayor]

If you are a student, I doubt you have an air separation plant.  However, you might have an assigned problem.  Please be clear and accurate; state your query correctly.

 

Do you want to find the moisture content in the feed air so that you can calculate the required adsorbent process to remove the moisture?  What is "MSA".  Don't use acronyms without defining what they represent.

[P.K.Rao]

You can determine moisture content in compressed air by dew point.

[shan]

You will be able to determine you air water content  (lb H2O/lb Dry Air) per amine temperature and relative humidity per Psychrometric Chart.

[thorium90]

Alternatively, you can use steam tables to find the saturation pressure of water for the inlet temperature of the air, multiply that by the relative humidity to get the moisture partial pressure, multiply by atmospheric pressure to get mole fraction.

Find isotherm data for the adsorbent, mmol/cm3 amount adsorbed by mmol/cm3 amount in concentration. If it is to be temperature swing adsorption, find the curve with different temperatures. This curve will tell you how much will be adsorbed and how much will be removed during regeneration, which is essentially the difference between the two curves. There are also sizing equations for residence time etc, using information from the breakthrough curve. Might be helpful to read some books on adsorption columns.