High Temp on Shell of Shell and Tube Condenser

[RJB32482]

Hello,
We are having troubles with our of our condensing units on a polystyrene batch reactor. This unit condenses styrene vapors while charging the reactor with styrene and also venting at 90C when sampling. Shell side is a 50/50 glycol/water solution and tube side is the process vapor (styrene). Currently, we are having issues with a high temperature on the outlet of the glycol shell. The flow through the shell is good, but temperature is not. So I am not thinking any issues with the shell side of the condenser.

But my thought is that if the tubes were plugged, that your temperature in the glycol would decrease (less heat transfer area = less heat transfered to shell side = less temperature change). Any thoughts on that?

Glycol chiller unit also supplies 11 other reactors and no issues with those temperatures while venting to those condensers. Same process in those reactors as with this problem child.

Thanks in advance.

 

[dcasto]

I'd think that you have a polymer build up on the tube side cause an insulation effect.

 

[MikeHalloran]

The high shell effluent temperature suggests that the glycol flow is not 'good'; how are you measuring it?



Mike Halloran
Pembroke Pines, FL, USA

 

[djack77494]

You need to properly troubleshoot your exchanger's operation. As far as possible, try to determine SS & TS inlet and outlet temperatures and flowrates. If your process parameters meet your expectations except for the duty (outlet temperatures), than you are likely experiencing some sort of fouling. (In your service, I would think polymerization on your tubes' outer surfaces to be a distinct possibility). If one of your flowrates is off, you may have a physical obstruction or some sort of unexpected hydraulic losses. It should be easy to get the temperatures you need; flowrates may be more difficult to come by, but I'd think you could come up with a way to at least estimate the glycol flow. Final determination of the problem may require disassembling and inspecting the exchanger. Good luck, Doug.

 

[sshep]

As Mike pointed out the glycol coolant flow isn't good, or you are condensing more styrene than you think. These are about the only real possibilities (as opposed to bad measurements). This conclusion is directly from the energy balance irrespective of any pluggage. With respect to pluggage, only a glycol side restriction makes any sense.

This will be easy to solve if you get the data djack asks for.

best wishes,
sshep