Options for improving packed bed performance when in turndown

[Thiophilus]

For those still populating this NG:

I have a packed catalyst bed that is treating a gas (rhetorically).
The bed is in turndown (much lower flow than design), and performance
is suffering. I would like to take steps to improve the performance.

Okay, one thing I could do is load a catalyst with smaller particle
size. That would result in a higher pressure drop. With a higher
pressure drop, I'm thinking there will be better plug flow (less
channeling), and that should give better results.

On the other hand, I could put in a catalyst with LARGER particle
size. That would give me a higher Reynolds number, which means more
turbulence in the bed. And more turbulence means better mass transfer
and better performance.

Which alternative is right? Does it depend? On what? Where can I learn
more about flow regimen in packed beds in gas service?

Th

[dlzc]

Both of us... Might want to ask on sci.chem... a few more there.

Post by Thiophilus
I have a packed catalyst bed that is treating
a gas (rhetorically). The bed is in turndown
(much lower flow than design), and performance
is suffering. I would like to take steps to
improve the performance.

Install huge dunage.

Post by Thiophilus
Okay, one thing I could do is load a catalyst
with smaller particle size. That would result
in a higher pressure drop.

No, it wouldn't.

Post by Thiophilus
With a higher pressure drop, I'm thinking there
will be better plug flow (less channeling), and
that should give better results.

No, it won't.

Post by Thiophilus
On the other hand, I could put in a catalyst
with LARGER particle size. That would give me a
higher Reynolds number, which means more
turbulence in the bed. And more turbulence means
better mass transfer and better performance.

A better idea, but you might worsen wall effects.

Post by Thiophilus
Which alternative is right? Does it depend?
On what? Where can I learn more about flow
regimen in packed beds in gas service?

Recommend (if possible) blowing outlet gas back to inlet, to get the flow rate up.

David A. Smith

[Thiophilus]

X-posting to sci.chem...

Post by dlzc
Both of us... Might want to ask on sci.chem... a few more there.

Post by Thiophilus
I have a packed catalyst bed that is treating
a gas (rhetorically). The bed is in turndown
(much lower flow than design), and performance
is suffering. I would like to take steps to
improve the performance.

Install huge dunage.

Post by Thiophilus
Okay, one thing I could do is load a catalyst
with smaller particle size. That would result
in a higher pressure drop.

No, it wouldn't.

Post by Thiophilus
With a higher pressure drop, I'm thinking there
will be better plug flow (less channeling), and
that should give better results.

No, it won't.

Post by Thiophilus
On the other hand, I could put in a catalyst
with LARGER particle size. That would give me a
higher Reynolds number, which means more
turbulence in the bed. And more turbulence means
better mass transfer and better performance.

A better idea, but you might worsen wall effects.

Post by Thiophilus
Which alternative is right? Does it depend?
On what? Where can I learn more about flow
regimen in packed beds in gas service?

Recommend (if possible) blowing outlet gas back to inlet, to get the flow rate up.
David A. Smith

[Thiophilus]

Post by dlzc
Both of us... Might want to ask on sci.chem... a few more there.

Post by Thiophilus
I have a packed catalyst bed that is treating
a gas (rhetorically). The bed is in turndown
(much lower flow than design), and performance
is suffering. I would like to take steps to
improve the performance.

Install huge dunage.

Could you elaborate?

Th