9 replies to this topic

[Mohsen Khodaee]

Hello every one

I'm studying a cycle which is attached in pdf format. I used HYSYS software to simulate this cycle. This Cycle is used to liquify butane. For refrigeration cycle I use propane. The refrigeration cycle which is shown in black color has a compressor with 3 stage. My goal is to optimize this refrigeration cycle. I want to know if mas flow of every branch is not assumed constant, the actual volume flow of every stage of compressor should consider constant or not? and does anyone know when I should take actual volume constant?  ButaneLiquefaction.pdf   95.18KB   24 downloads

 

For understanding this sketch, a picture of simulating this cycle in HYSYS software has been uploaded: https://uploadfiles.io/a003516

 

Mohsen

Edited by mhsnkhd, 12 July 2016 - 11:08 AM.

[Bobby Strain]

First you should review your flow sketch. This is not the way to set up your refrigeration cycle. So do some more study first.

 

Bobby

[Mohsen Khodaee]

Hi Bobby

Thanks for your comment. This sketch is adopted from a real case study and belong to an Italian company. Can I ask you what's wrong with this refrigeration cycle?

[Mohsen Khodaee]

Here is an explanation about the refrigeration cycle. In this cycle 3 kettle type heat exchanger are used (148-E-101, 148-E-102, 148-E-103). When the stream from expansion valve goes trough these heat exchangers, its gaseous phase continue to the 147-D-101,102,103 and its liquid phase goes down which is not shown in the pdf attachment. It means that for example for 148-E-101 the stream from V-1 is entered to the 148-E-101 and separate in two phase and its gaseous phase goes through the 147-D-103 and its liquid phase goes through the V-2.

 

Mohsen

Edited by mhsnkhd, 12 July 2016 - 10:51 AM.

[Bobby Strain]

When you copy a design, you should first ascertain that is a sound work. Look around some more for a better design. And use the search facility at this site. You can start by looking at the similar topics listed below

 

Bobby

Edited by Bobby Strain, 12 July 2016 - 11:48 AM.

[Mohsen Khodaee]

Hi Bobby

Thanks again. I would like to know what is wrong with this cycle? I mean the design is not clear or the cycle is wrong?

Did you see the picture for HYSYS simulation? https://uploadfiles.io/a003516

[Bobby Strain]

Best to attach your HYSYS PFD to your response. The attachment feature is easy to use.

[Mohsen Khodaee]

Ok dear Bobby. I've attached a picture of PFD for this cycle. My final goal is to optimize this cycle and there are a lot of variables. This cycle is a simplify of a real case. I would like to know that if I should use "adjust" for each stage of compressor to make "actual volume flow or not" constant? And if the answer is yes, then which variable should consider as independent variable that is changing to make actual volume flow constant? Thanks for your help Bobby.

Attached Files

•  Capture.JPG   34.7KB   0 downloads

[Bobby Strain]

edit:

You simulation is the proper flowsheet. But you have too many recycle operations. You need only one at the condenser or compressor discharge. Use adjust operations to achieve the required duty for each exchanger. Plan them carefully. You must include liquid refrigerant bypass valves at each stage except the lowest pressure.

 

Check this.  http://www.peerlessx...cuments/511.pdf

And attach a screen shot of the HYSYS PFD, not the actual simulation file, after you set the flowsheet like the one in the reference. Just get the simulation working first. Once you have it running, you can change some variable(s) without adjust operations. Give it some thought after observing the effect of different variables. This will give you ideas about how to optimize. But you won't really optimize without knowing cost of the installation and utilities for operation. And fit conditions for commercial compressors.  All you will really achieve is learning how to use the simulator for various tasks.

 

Bobby

Edited by Bobby Strain, 12 July 2016 - 02:53 PM.

[Mohsen Khodaee]

Thanks a lot dear Bobby.