Heat exchanger duty in upset case
Heat exchanger duty in upset case
(OP)
I have a heat exchanger with a PSV on the cold side. My scenario is control valve failure on the hot side sending more hot fluid via the exchanger than is quoted on the data sheet.
Is there a simple way for me to estimate worst case heat transfer rate to the cold side for this scenario?
Thanks.
Is there a simple way for me to estimate worst case heat transfer rate to the cold side for this scenario?
Thanks.





RE: Heat exchanger duty in upset case
1) Use heat exchanger software (e.g. HTRI or Aspen EDR), option "rating" for the exchanger with known geometry and fluid properties/flowrates. The software will estimate outlet temperatures for both fluids and hence the new duty point.
2) Calculate how much the overall heat transfer coefficient increases (as compared to the base case) when one side of the exchanger sees higher flow. Although the LMTD will also change in this case, the increase of the overall U should give you some estimation - a figure at least being in the same order of magnitude as the real one.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Heat exchanger duty in upset case
that' really amazing !
RE: Heat exchanger duty in upset case
Dejan IVANOVIC
Process Engineer, MSChE
RE: Heat exchanger duty in upset case
I've never seen an abnormal heat input case for an exchanger like you are describing... usually we only consider isolation of the cold side with continued heat input, which we would do a PRO/II rigorous exchanger model to estimate duty.