scale up of reactor 5

[bond007engg]

Hi,
I want to know how to scale up reactor : from 0.1 T to 10T of capacity. Please provide formulas and other information for this.

 

[Montemayor]

James:

Let me get this straight. You want to scale up a "reactor" by a factor of 100 times and you are requesting "formulas" for doing this from a bunch of guys that you don't even know.

Besides the above, you haven't even revealed the type of reactor you're talking about - or whether it's continuous or batch, nuclear, or otherwise. Needless to say, the raw materials, products and process conditions haven't even entered into the basic data furnished.

By the nature of your question I can only suppose that you have no experience in doing this. What would you do with any recommendations or answers if you don't know the sources or their veracity? Is this an academic exercise or simply a theoretical question? I'm afraid most of us on the forum can't offer any comments based on the scarcity of basic data and background information. Sorry.

 

[sshep]

Gentlemen,

How does a reply telling someone they are making a foolish post merit a 3 star rating? Unless Mr Montemayor has a ridiculously inflated ego for someone of his experience(which I doubt), he does not need 3 star praise for an obvious response. Montemayor gives loads of useful information which are much better candidates for gratitude. This type of shallow recognition dilutes the value of recognizing truly useful posts, and is contrary to the spirit of the rules of these forums.

best wishes, sshep

p.s. Montemayor, no disrespect intended. Thanks for all your previous help.

 

[Montemayor]

Shep:

Thanks. I wasn't looking for any stars on this; rather, I was probing for more basic data and information. I'm also trying to disprove the existing of a "formula" that will scale up a reactor and allow us to wash our hands of all the necessary research and investigative work that has to be done before approving of such an expensive enterprise.

 

[sshep]

007,

McGraw Hill publishes a book titled "Fundamentals of Chemical Reaction Engineering" which some of my peers used as a school text, and which I have borrowed from time to time. If memory serves there is a short section with a general procedure on how to get from bench scale to production scale, but as Montemayor pointed out there is no set of equations to do this.

The typical scale-up approach combines experimentation and incremental reactor size increases- i.e. bench scale, pilot scale, field test, etc. There is generally too much economic risk to attempt a large scale-up in one shot. Perhaps you could get by in the case of a homogeneous liquid reaction, but for most hetergenous reactions, the number of factors influencing the reaction and reactor design are simply too great to risk it.

Anyway, would love to hear more about the reaction you are attempting.

best wishes, sshep

 

[m777182]

There is a large amount of books about scale up of reactors (or other chemical equipment).The smaller is the scale up factor the better is result, but scale up factors 1000 should be avoided.The main problem is that processes are related to mass and energy transfer and if we reduce the rate of reaction to some power r of a linear dimension and energy transfer to some power q of a linear dimension (usually some characteristic dimension of a reactor) then the ratio of reaction rate to energy transfer cannot be kept constant by changing that particular characteristic linear dimension. If r and q differ much even a scale up factor 10 will not give reliable predictions.
m777182

 

[Eltron]

Hello All,

I'm with Art on this one. I don't think we should be making guesses at the scale-up of a nebulous "reactor" without knowing anything about it. All we will be doing is confusing the matter.

 

[sshep]

Eltron,

I am still getting a kick out of the fact that we award 4 stars for telling someone they are being foolish. Compare this with Montemayor's same day technical reply to Dewar Conversion (thread124-138153) which apparently only merits a single star. I won't feel bad then for giving some recognition to m777182 for quantifying a few reasons for why a 1000:1 scale-up is unwise.

Anyway... best wishes to everyone as always, sshep

 

[Latexman]

sshep,

I think Mr. Montemayor's posts got 4 stars because of the entertainment value. When I read the original post, I wanted to tell James some things that would have gotten deleted, so I didn't. Mr. Montemayor did it in his usual cool, calm, suave style and I appreciate that.

Good luck,
Latexman

 

[chemical67]

hi Montemayor sshep

thanks for suggestion, but i was forgetting to tell specific details.

Actually I worked at hydrogenator plant using Ni catalyst to produce finechemicals. I worked and commissioned Hydrogenator and also successfully taken first trial and we succeed to take out final product. Reactor was 4KL capacity-batch reactor with limped coil. Actually, I have no experience of scale up of reactor. That's why I want to know what are the procedures from laboratory- to pilot plant to main plant. How the things going on? What are the factors to be considered after successfully trial of pilot and laboratory reactor. Please give all the relevant details.

 

[sshep]

Chemical67,

I found an even better reference book in our library:

Title: Chemical Reactor Design, Optimization, and Scaleup
Publisher: McGraw-Hill
Copyright / Pub. Date: © 2002
ISBN: 0-07-137753-0
Electronic ISBN: 1-59124-390-4
No. Pages: 624
Author/Editor: By: Nauman, E. Bruce

This seems a pretty good reference text on the subject of interest.

best wishes, sshep

 

[azertyuiop]

HI All,

I am also busy with a new hydrogenation pilot plant processing refined vegetable oil, with the aim to reduce the iode number by a factor of 10, before further processing downstream.

The reactor system is dimensioned, but I am strugling with the hydrogen and nitrogen gas feed to that reactor. The Nikkel catalisator has to be activated (reduced), and that requires heating up the catalisator to 180°C with a mixture of 10% H2 and 90% N2, then slowly increase the H2 and decrease the N2 concentration, and end the process with a 95% H2 and 5% N2 gas mixture. That gas mixture is being injected into the reactor, after passage into a heat exchanger to bring it to 180°C, from their respective evaporation temperatures starting from liquid bottle phase.

my problems are :
a) H2 and N2 gas temperature in the downstream piping after their respective evaporation, prior injection into the heat exchanger bringing it up to 180°C with thermo oil. I need to determine the delta T needed for that heat exchanger (180°C - (gas temperature)), when considering outside winter temperature equal to minus 10°C (windchill factor not included due to insulation over pipe).

b) is flowcontrol or pressure control the main control system?
H2 flow rate = 18kg/h to be evaporated
N2 flow rate = 1000kg/h to be evaporated

c) how does the gas street to achieve this regulation and gas mixing look like?

d) what type of metal do I use? Copper, steel , SS (I think of using SS304L, my boss' recomendation, so no budget problems)

e) are there turn key suppliers on the market?

f) the suppliers of H2 and N2 aren't forthcoming, and I suspect they want to keep their hands off this pilot plant and it's eventual problems.

any input appreciated.

thanks.

 

[azertyuiop]

HI All,

I am also busy with a new hydrogenation pilot plant processing refined vegetable oil, with the aim to reduce the iode number by a factor of 10, before further processing downstream.

The reactor system is dimensioned, but I am strugling with the hydrogen and nitrogen gas feed to that reactor. The Nikkel catalisator has to be activated (reduced), and that requires heating up the catalisator to 180°C with a mixture of 10% H2 and 90% N2, then slowly increase the H2 and decrease the N2 concentration, and end the process with a 95% H2 and 5% N2 gas mixture. That gas mixture is being injected into the reactor, after passage into a heat exchanger to bring it to 180°C, from their respective evaporation temperatures, starting from liquid bottle phase.

my problems are :
a) H2 and N2 gas temperature in the downstream piping after their respective evaporation, prior injection into the heat exchanger bringing it up to 180°C with thermo oil. I need to determine the delta T needed for that heat exchanger (180°C - (gas temperature)), when considering outside winter temperature equal to minus 10°C (windchill factor not included due to insulation over pipe).

b) is flowcontrol or pressure control the main control system?
H2 flow rate = 18kg/h liquid to be evaporated
N2 flow rate = 1000kg/h liquid to be evaporated

c) how does the gas street to achieve this regulation and gas mixing look like?

d) what type of metal do I use? Copper, steel , SS (I think of using SS304L, my boss' recomendation, so no budget problems)

e) are there turn key suppliers on the market?

f) the suppliers of H2 and N2 aren't forthcoming, and I suspect they want to keep their hands off this pilot plant and it's eventual problems.

any input appreciated.

thanks.