2 replies to this topic

[zhitingchong]

Hi, 

 

So I am supposed to replicate a certain simulation in HYSYS based on a given literature.

So these are the literature PFD 

 

Stream Entering the column(at Stage 11) : 
Molar Flow Rate : 178.1 kmol/h

Pressure : 5.8 bar

Temperature: 103 Degree C

Stage Number: 20

 

 

 

 

And the stream compositions which I am supposed to replicate

 

 

Stream 6 (liquid overhead) : 
Molar Flow Rate : 116.4 kmol/h

Pressure : 6.5 bar

Temperature: 45 Degree C

Vapour Fraction: 0.0

Composition: Mainly Butane, Butene and Propane

 

Stream 7 (vapour overhead): 
Molar Flow Rate : 3 kmol/h

Pressure : 5 bar

Temperature: 45 Degree C

Vapour Fraction : 1.0

Composition : Pure Propane

 

Stream 8 (bottoms): 
Molar Flow Rate : 58.65 kmol/h

Pressure : 5.8 bar

Temperature: 151 Degree C

Vapour Fraction : 0

Composition :Mainly  Hexenes and Heptenes

 

 

 

 

 

 

Below I have tried following the PFD distillation column specifications below is my distillation column settings

 

 

Stream Entering the column(at Stage 11) : 
Molar Flow Rate : 178.1 kmol/h

Pressure : 5.8 bar

Temperature: 103 Degree C

Stage Number: 20

Reboiler Pressure: 5.8 bar
Condenser Pressure: 5.5 bar

Reflux Ratio: 3

Distillate Rate : 116.4 kmol

Vapour Overhead Rate : 3kmol

 

 

But yet I couldnt get the propane component to go into the vapour overhead (Stream 7) instead it went into the liquid overhead (stream 6).

 

The molar flow rates of propane specifically 

 

Stream 6: 3.35 kmol/hr    Stream 7: 0.21 kmol/hr

 

Do advice, what am I doing wrong. What settings can I change to achieve the proper propane seperation?

Edited by zhitingchong, 08 November 2017 - 11:36 PM.

[serra]

I would suggest to post these questions in Student's forum,

 

you have a 20 trays column with a single feed (on tray 11) a reboiler (stream 8) and a partial condenser (streams 6,7),

the procedure has to solve two additional vars (reboiler duty and condenser duty),

you know flows (specified) : which are your spec's ?

Before to proceed you may wish to read some good text discussing the basis of distillation model,

 

it shouldn't depend from simulator,

(nowadays most software include variants of both Russell's Inside-Outside and Newton procedures)

but from your capability to define the correct inputs (thermodynamic models, column spec's)

 

you may use Aspen, Chemcad, VMGSim etc. (I use Prode Properties) to obtain similar results,

 

I can't say more considering that you do not provide all the details of your problem,

however, you can, for example specify a component's fraction so that procedure varies reflux (temperatures and V/L flows) or select different models for fugacity, H ....

Edited by serra, 09 November 2017 - 04:27 AM.

[Padmakar Katre]

Hi, 

 

So I am supposed to replicate a certain simulation in HYSYS based on a given literature.

So these are the literature PFD 

 

Stream Entering the column(at Stage 11) : 
Molar Flow Rate : 178.1 kmol/h

Pressure : 5.8 bar

Temperature: 103 Degree C

Stage Number: 20

 

 

 

 

And the stream compositions which I am supposed to replicate

 

 

Stream 6 (liquid overhead) : 
Molar Flow Rate : 116.4 kmol/h

Pressure : 6.5 bar

Temperature: 45 Degree C

Vapour Fraction: 0.0

Composition: Mainly Butane, Butene and Propane

 

Stream 7 (vapour overhead): 
Molar Flow Rate : 3 kmol/h

Pressure : 5 bar

Temperature: 45 Degree C

Vapour Fraction : 1.0

Composition : Pure Propane

 

Stream 8 (bottoms): 
Molar Flow Rate : 58.65 kmol/h

Pressure : 5.8 bar

Temperature: 151 Degree C

Vapour Fraction : 0

Composition :Mainly  Hexenes and Heptenes

 

 

 

 

 

 

Below I have tried following the PFD distillation column specifications below is my distillation column settings

 

 

Stream Entering the column(at Stage 11) : 
Molar Flow Rate : 178.1 kmol/h

Pressure : 5.8 bar

Temperature: 103 Degree C

Stage Number: 20

Reboiler Pressure: 5.8 bar
Condenser Pressure: 5.5 bar

Reflux Ratio: 3

Distillate Rate : 116.4 kmol

Vapour Overhead Rate : 3kmol

 

 

But yet I couldnt get the propane component to go into the vapour overhead (Stream 7) instead it went into the liquid overhead (stream 6).

 

The molar flow rates of propane specifically 

 

Stream 6: 3.35 kmol/hr    Stream 7: 0.21 kmol/hr

 

Do advice, what am I doing wrong. What settings can I change to achieve the proper propane seperation?

 

Pls share Hysys simulation file for members to look what needs to be corrected.