Heat Transfer for Condensing Styrene 1

[RJB32482]

Hello Everyone,
I am trying to see if our current cooling system is capable of condensing styrene vapors from our reactor during sampling and charging styrene if we add another exchanger. We currently have a 50% propylene glycol solution going through the shell side of the 7 condensers on 7 reactors. We want to add one on an 8th reactor. I believe testing was done to see the mass flowrate of styrene during each of the conditions (charging and sampling). I can see from literature the cooling capacity of the chiller system (cools the glycol after it goes through the exchangers).

How can I check if adding another exchanger will be too much for our cooling system. The reactor is at ambient during charging and about 90C during sampling. Would I just need to calculate heat needed to be taken away to cool styrene to its boiling point then the heat of vaporization of the syrene vapor for one exchanger, times it by 8, then see if our chiller unit can handle cooling the glycol enough? Maybe also look at how adding the temperature changes in the glycol after heat transfer in the condensers?

Thanks.

 

[Yorkman]

Some of the checks to make first at full design styrene production for 7 condensers would be : Are you at full capacity (heat rejection) at the cooling tower or air cooled condenser now, can your glycol pumps handle the pressure drop of another condenser or do you add another pump, is your chiller running at full amperage now?
If you have room to "expand" then you will need to find: The design mass flow of the styrene, the specific heat of styrene as a gas if the gas is super-heated, how many degrees it's superheated, the specific heat of styrene as a liquid if you intend to sub-cool the product, you will need to know the desired [Δ]T of the sub-cooled liquid, and finally (I think) the latent heat of condensation/vaporization at design pressure. That will get you pretty close for determining your BTU/Hr or Kw/hr heat load.

I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int./JCI

 

[djack77494]

I think you're approaching this problem in a more difficult manner than necessary. If you can determine the flowrate of glycol to one or all of your condensers, and if you have the corresponding inlet and outlet temperatures, then you can calculate the actual current duty you are getting from your chiller(s). Multiply by 8/7 and you'll see what you need if you add another reactor. Is your current cooling system rated for this? If so, check the hydraulic capability and you're home free. If not, I'd suggest a call to the supplier of the cooling system.
Doug

 

[Yorkman]

AUUHHHH, Come on Doug your taking all the fun out of it!!

I'm not a real engineer, but I play one on T.V.
A.J. Gest, York Int./JCI

 

[djack77494]

Sorry, but isn't that what engineering is all about?? :-|)

 

[leejs]

I think djak77494's reply is applicable.
There exist factors like heat transfer limitation and heat loss difficult to be determined, the calculation based on your shell side rather than tube side would be much more correct and practical. If your current condensing system is found not to be enough, you may upgrade your circulation pump(to increase the flowrate of coolant) or expand your cooling system(to decrease the temperature of coolant). Or you may change your coolant material.