heat exchanger evaluation 1

[engr45]

i am facing problem during evaluation of heat exchanger at crude distillation unit.during UD calculation of heat exchangers major prblem is to calculate specific heat of curde oil and different fractions with respect to operating temp and pressures..how can calculate specific heat and accurately avaluate heat exchangers performance..could i have to use any software?

 

[Homayun]

You make a fairly easy evaluation by using the basic Heat Transfer formula Q=A.U.LMTD

By measuring the inlet/outlet temperature on both sides you can calculate the LMTD. Further you can also estimate the Duty (Q). Then you can establish your AU value. This will be done for the base operation.

Then for the new operation, you will certainly have a new Q and a new LMTD from your simulations. THen you can calculate how much the new AU value is. IF the new AU value is by far greater than the Base UA, then your exchanger is undersized. If it's lower, the chance is that your exchanger will be performing wel.

Note: If you wanna be conservative, you may wanna debit your new UA value let's say by 10% or so.

But there are also some software like HTRI that can be used to evaluate an exchanger, but you must have some experiece in that first. It's not a very easy tool to use.

 

[engr45]

any artical about heat exchanger evaluation of any calculation reference which may lead to perfect results

 

[TD2K]

The API data book and the TEMA data books have correlations and typical values for heat capacity, viscosity, thermal conductivity, density, etc for hydrocarbons. Do you have access to those?

 

[unclesyd]

All you ever wanted to know about heat exchanger/transfer and more from Wolverine Tube.

http://www.wlv.com/products/thermal-management-databooks.html