Problems With Waste Heat Reboiler 1

[Concepts12]

We have two Waste Heat reboilers in parallel in which the effluent gas from the turbines are used to heat up the TEG and water mixture in the ratio 75:25 respectively. The readings obtained showed that the flow rate of the TEG mixture out of the Reboiler is greater that the flow rate into the Reboiler.
The reboilers are run on TEG flowrates less than that designed.
What problems can be causing these problems given that there are no leaks in the reboiler.
Also what are the complication associated with running a reboiler under its design tube flow rate.
Any help extended will be greatly appreciated.

 

[sshep]

Hey Concepts12,

This doesn't sound like a reboiler in the context that anyone in this forum will recognize, rather it sounds like just a heat exchanger with hot gas on one side and cold liquid on the other.

98% sure one of your flows is reading wrong, to find which one you need to do an energy balance on the gas side.

For a liquid with no phase change there is no reason to fear the lower flow lower provided that it will not exit too hot- i.e. you could get it so low as to boil, etc. Reduced heat transfer as a result of low velocity is probably not a concern- the heat requirement is also lower and so you have proportionately greater area and LMTD.

best wishes,
sshep

 

[JLSeagull]

If the gas flow transmitters are not corrected for temperature and pressure the flow rate will appear higher for the same flow at the higher temperature than at the lower temperature.

 

[Concepts12]

The piece of equipment is actually a heat exchanger to be correct.

Thanks sshep and JLSeagull.