2 replies to this topic

[prohackerav]

Dear all,

 

I am a student trying to design a small sized packed column using molecular sieves for the drying of air. The basic requirement of the design is to achieve a controlled atmosphere with less than 50ppm concentration of water vapour in a slightly pressurised chamber (of approx 1000cm3 volume) where we can do water sensitive synthesis in a laboratory scale. Please help me out with pointers on where to start and how to design the same. There is no requirement of using 2 columns consecutively for regeneration purposes. One column is sufficient but has to work for longer time spans in adsorption cycle.

 

Point me out in the right direction on where and how to start and also what kind of sieves to use. The air will be vaccumed first and purged with N2 for creating an inert atmosphere so the stream would mostly consist of Nitrogen and trace amounts of air constituents.

 

Hoping for a reply soon.

 

[breizh]

hi ,

 

a few documents to support your work .

You may find additional resources in this forum using the search engine .

 

Hope this is helping you.

Breizh

 

[Art Montemayor]

You ask to be pointed out in the right direction.  The following are my points:

• The basic, applicable information on how to design an adsorption vessel for drying a gas is furnished by Breizh.  Read and study it thoroughly and you will find it sufficient to do your assignment.
• Your communications skills need a lot of improvement.  The scope of work and basic data you furnish don’t give a clear and accurate description of what you think you are to do.
• You state you are “trying” to design an adsorption unit.  What is the real story?  Have you been assigned to do it?  Or are you “trying” to see if you can do it?  Be specific.
• You want to achieve a "controlled atmosphere".  This is of no basic interest and has no data for designing an adsorption unit.  The main point here is: what is the moist gas feed rate to the adsorber - and is it a steady, continuous flow?  Your description of what is needed is confusing.
• You state the chamber will be initially vacuumed and filled nitrogen.  So what?  What does that have to do with the need for an adsorber?  Is it moist nitrogen that will be sent to the adsorber? - or is it moist air?  If air (as you state), how and where does it get wetted?  what role does the nitrogen play?
• Is this a batch operation?  Or is it continuous?
• What is the moist feed (nitrogen or air?) feed rate and what is its moisture content.
• An adsorption process does not produce a given, specific continuous product water content.  It produces a dry gaseous product that has a water content “not to exceed” a maximum value.  That value is usually much less than what you need.
• In order to give you more information on where to start and how to design an adsorption column our members need SPECIFIC basic data: Is the operation batch?  What is the flows of wet feed gas and its moisture content?  Do you need to regenerate or is the operation only for one time only?