Aspen EDR studies
Aspen EDR studies
(OP)
Hello...
I am running EDR for the first time...I need to heat a heavy stream of crude from 150 to 240 C....Different heating mediums are being considered and one among them is hot oil...I know the hot oil inlet and outlet temperatures...I am estimating the hot oil flowrate required using a simple heat exchanger...I am attaching a picture below..
when I do EDR with that the previously estimated hot oil flowrate...the heavy stream is getting heated to around 256 instead of 240 and the hot oil outlet stream is lesser than the sepcified outlet temperature of 270 C...
What can i do in this case ? Should I reduce the hot oil flowrate estimated and use lesser quantity or reduce the number of tubes ??
I am attaching the screenshots below..
Thanks in advance !!


I am running EDR for the first time...I need to heat a heavy stream of crude from 150 to 240 C....Different heating mediums are being considered and one among them is hot oil...I know the hot oil inlet and outlet temperatures...I am estimating the hot oil flowrate required using a simple heat exchanger...I am attaching a picture below..
when I do EDR with that the previously estimated hot oil flowrate...the heavy stream is getting heated to around 256 instead of 240 and the hot oil outlet stream is lesser than the sepcified outlet temperature of 270 C...
What can i do in this case ? Should I reduce the hot oil flowrate estimated and use lesser quantity or reduce the number of tubes ??
I am attaching the screenshots below..
Thanks in advance !!


RE: Aspen EDR studies
Reducing the hot oil flowrate will lower the outlet temp of the heavy as less heat is carried into the HX to give up to the heavy. Less heat is also given up by the hot oil to the heavy, so hot oil outlet temp will tend to increase.
On the other hand, increasing number of tubes increases heat transfer from hot oil to heavy, which will tend to increase heavy outlet temp and reduce hot oil outlet temp
--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
RE: Aspen EDR studies
Actually I wanted to decrease the number of tubes...not increase them...so which would be a better option ? reducing the hot oil flowrate ?
And I have done the simulation using 1-shell, 2-tube pass...it is showing temperature cross because the outlet temperatures are different from requirement as mentioned in the previous post...whereas for 1-shell, 1-tube pass, there is no temperature cross...is 1-shell, 1-tube pass common in industry ?Can i go for 1-shell, 1-tube pass ?? This is just a preliminary design stage..
Thanks in advance !!
RE: Aspen EDR studies
One tube is not common. Usually there are quite a few tubes to maximize heat transfer surface for a more efficient heat exchange. One or two tubes will not have much surface area and a lot of both fluids will not come in thermal contact, simply running through the equipment for nothing. One or 2 tubes also suggest that a shell and tube exchanger is the wrong type of exchanger to use.
--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
RE: Aspen EDR studies
I will try decreasing both and check !!
RE: Aspen EDR studies
Please let me know how that goes.
--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."
RE: Aspen EDR studies
Coming to pump and piping...actually hot oil is one heating medium we are considering...there are 3 more (steam, electric and feed/product heat integration)...so i think once the heating medium is finalized we have to look pump requirement !! This project is being done by other department , so i dont have many details regarding the whole scheme yet...
Thanks
RE: Aspen EDR studies
-Christine
RE: Aspen EDR studies
that is why I had a doubt if 1-shell, 1-tube pass can be used or not
thank you @christine