removing water from co2 stream 1

[offonoff]

I have a co2 gas stream to be captured and stored. 400 psi and below room temp. Water must be removed first. We are thinking 1/4" stainless into a filter with an adsorbant into 1/4" carbon steel pipe. Any suggestions about filter manufacturers or filtration strategies?

so many good ideas around this forum. thanks

 

[zdas04]

There are any number of PSA units (pressure swing adsorbtion) units on the market, the big drawback is that with pressure alone you can't evolve all the water out in a reasonable regen time.

It is more common to use TSA (temperature swing adsorbtion) units to cook the water out of the beds. This requires adding considerable heat (call it 6500 BTU/lbm of water) that has to be carefully applied (i.e., if you try to do it with immersion heaters you'll melt your adsorbant near the heater and not get any heat to the rest of the bed. The only time I've seen this done successfully was in an air plant that used hot rocks to store most of the heat between regen cycles, a lot of warm moist air was vented, but so what?

You can get a long ways toward "dry" with a membrane unit, but you have to be willing to accept a significant waste stream.

You didn't talk about the volume of gas being processed so I don't have any idea what size problem the regeneration would be.

David

 

[Montemayor]

offonoff:

What you are proposing in concept is done everyday industrially - and commercially. It is a piece of cake. Practically all bulk CO2 sold world-wide (& there are probably thousands of tons sold daily) is processed, stored, transported and distributed as a liquid at about 250-300 psig and -8 oF (saturated). To do that, it is dryed in the gaseous state to approximately 1 ppm of water moisture using solid adsorbent (usually Activated Alumina - Molecular Sieves are an over-kill here).

If you are talking about using 1/4" tubing, you are either "experimenting", new at this, or have a very, very small laboratory setup for a very small CO2 flow rate. If it is the latter, you probably have problems in compressing a very small volume of CO2. If you tell us ALL of the basic data you have, perhaps (as David infers) we can help you further. Otherwise, all we can do is guess.

 

[offonoff]

I am new at this, "experimenting", and have a small laboratory setup. all three. My concept is probably pretty naive, so its best you hear the whole system.

This is the co2 reclamation section of a liquid co2 solvent process. liquid CO2 at 900-1000 psi dissolves hydrocarbons out of a substrate and then is expanded in a chamber to gas at 400 psi, dropping the dissolved liquids. The flow rate is low to prevent rapid cooling of the reaction chamber.

The expansion chamber is held at room temperature by a water bath, and a connected tank is held at low temp (0C) by a refrigeration unit. the temperature of this tank determines the pressure in the system (the vapor pressure of co2 at that temp) ideally. filters will cause pressure difference.

The pipe connecting the expansion chamber to the liquefaction tank should filter (mostly water) from the gas stream. An unreasonably high ammount of water per batch cycle would be several pounds. probably would be more like ounces (the material washed will be dry), but better to over size and not have to regen every batch.

I believe i will not have to compress the co2, and that a refrigeration unit will cause the liquefaction.

 

[dcasto]

without size and water specification I can't recommend much. But at large volumes and to meet pipeline CO2 specifications, a TEG dehydration system will work.