How to maintain the same concentration when space velocity changes?

[KEYWORD]

When I set CO at 500 ppm with 300,000 GHSV, I can get a very close concentration (495-510ppm). However, after space velocity decreases to 200,000 GHSV, CO concentration goes down to 450 ppm. Theoretically, it should maintain the same concentration. Do somebody know what cause this problem and how to fix it? Thanks!  Jim

[AnalogKid2DigitalMan]

Use a smaller reactor? I have no clue 🙂

Jim:

This is a LabVIEW programming language forum, you may find someone familiar with what you are talking about, there are people from all disciplines that visit here.

But you would have a better chance on a forum more related to your query.

Good look!

-AK2DM

[KEYWORD]

Thanks for your reply! I tried to get an answer from searching, but I failed to get any similar questions.  My reactor has 0.67" diameter and its height is 28". The sample is 0.75 high. I don't know if this information is enough for you. If not, please feel free to let me know. I really appreciate your help.

[SchamWow]

GHSV is equivalent to reactant gas flow rate divided by reactor volume.

This means if GHSV is changing and your reactor volume is constant, the reactant gas flow rate will be changing.  This also means that our ppm value will change.  I don't think there is a way that you can keep the ppm value constant unless you measure for a different amount of time.

[KEYWORD]

There is a program called GHSV sweep in the program control mode. This means ppm should be constant when space velocity is sweeped from high velocity to low velocity. PPM should be controlled by the program. However, when I ran this program, I ALWAYS saw ppm changes. I wonder what caused this problem. Thanks you all for any discussion. Jim