1 reply to this topic

[mb2011]

Hello Everyone,

 

I want to put forward an idea to my company i am working for (as an intern)

 

right now a gas/liquid reaction is taking place in an agitated vessel. Due to confidentiality, I cant give any info abt materials involved. Except that the reaction could be said as fast.

To avoid contaminant by a series reaction, liquid quantity is deliberately kept large(3-4times), this means a lot of energy used to heat up the batch is wasted/not fully utilised to produce.

 

I want to use a Plug Flow Reactor, to make process continous and save significant energy without product contamination, but not sure how would be the conversion like?

most Importantly is it possible to attain a large amount of surface area for sufficient gas/liquid mass transfer in the first place?

 

Since very little resource about gas/liquid reaction in PFR is available and experience in this field is something i don't have access to, I just thought to write in this forum and hope someone would enlighten me from his/her experience. 

 

Any insight in this matter would be highly appreciated.

 

Best Regards

mb

[Saml]

Congratulations. You have a restless mind. But in this case you are most likely wrong.

 

Let me tell you a story. I like to tell stories. My very first boss asked me "what is the right thing to think when you see a PFD or a P&ID", I just stared at him. "It can be done better, he told me. Because it was done in another time, with another technology available, other market condition, other tools for calculation, orther costs, other a lot of etcéteras. So, everytime you see a process think: it can be done better".

 

Now, the hard part. When you go out of college, no matter if you are a gold medal student, you know only the academics. So your "can be done  better" ideas will be shot down in milliseconds. You will have probably 50 of these ideas that an older engineer will explain you why it is not a so good idea. The 51st, you will hit. And you will remember it for the rest of your career.

 

When you go more experienced your hit/reject ratio will go to 1:5 or 1:10, but only because you don't speek about all the others you thought about, made a quick numbers and decided that it had no future. If you count these, the ratio is still 1 in 50.

 

That is why I think you are almost likely wrong, just a matter of possibilities. But  keep thinking this way. Even if you get to nowhere you will learn. Remember the Edison's phrase: "I have not failed. I've just found 10,000 ways that won't work"

 

In this particular case, It seems that you have an excess of liquid reactant to avoid side reactions because the product further reacts with the gas to form a third compound. It is right?. If so, what make you think that in a plug flow reactor these same reactions would not occur, or that you will not need the same excess of liquid.

 

Your best option is to discuss this idea with a older engineer. As a recent graduate you should not feel ashamed if he/she shows the weak points of you proposal. Good chances are that he/she will explain you why your idea is not workable.

 

It is impossible for anyone here to help you about this, because nobody knows what it is, what the kinetic is, the heat of reaction, if the reaction is limited by kinetics or by mass transfer, what is "fast" (it is fast as a detonation, as an acid base neutralization, it takes a few seconds or it takes 5 minutes), what are the additional steps for product separation, what is the separation method, the scale of the plant, the flexibility of the facility (it is a single product all the time? it is a multiproduct?), etc

 

 

 

 

 

 

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Edited by Saml, 14 June 2017 - 05:23 PM.