Recent changes to 251: Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Daniel Medeiros — Tue, 21 Jul 2020 15:43:15 -0000

I've tried your simulation with Nested Loops VLLE and it worked right away.

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Rizwan Al-Rahman — Tue, 21 Jul 2020 15:39:38 -0000

Hello

Thank you in advance Daniel for your help. I seem to be getting stuck at the very begining of my process which is separation. I have oil, gas and water coming in to a separator. For this three phase separator, I am expecting to have some flow rate on the heavy liquid stream. But it shows "0" on the mass flow. I have been trying different flash algorithms but it is not working. Can you please assist and tell me what I am doing wrong? Attached is the file I was working with.

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Daniel Medeiros — Mon, 18 May 2020 22:32:29 -0000

If you're not intereset on mutual water/HC solubility, you can use the Immiscible VLLE flash algorithm, setting Water as the immiscible compound. That's what I do in my projects, similar to yours.

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Daniel Medeiros — Mon, 18 May 2020 21:14:06 -0000

Also, by definition, if you use the VLE algorithm, you will not see two liquid phases at the separator outlet.

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Daniel Medeiros — Mon, 18 May 2020 21:09:50 -0000

In the upcoming v6 release, although the mass flow balance is correct, the streams do not leave the separator in the saturation state. It seems that the VLLE flash result is not 100% correct. Also, the PR EOS has difficulties on calculating the compressibility factors for the liquid phases at the specified conditions, hence the inconsistencies. I've noticed that you did not defined a value for the missing interaction parameters, which is not an issue on HYSYS. That could probably help.

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Sameer Ningoo — Thu, 05 Dec 2019 14:08:35 -0000

I am sorry for typo- with HYSYS the HC Liq condensate flow is 2890kg/hr and water flow is 3152kg/hr.

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Daniel Medeiros — Thu, 05 Dec 2019 12:48:55 -0000

THE HYSYS output gives a HC liq condensate flow of 3152kg/hr and water flow of 3152kg/hr.

the mass flows are the same for both streams in HYSYS?

#251 Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Sameer Ningoo — Thu, 05 Dec 2019 11:27:29 -0000

Description has changed:

Diff:

--- old
+++ new
@@ -1,4 +1,4 @@
-1.The gas-liq separator gives different flows of the HC liquid and water when run with VLE and with VLLE Flash algortihm for the same amount of inlet wet gas flow (51948kg/h)
+1. The gas-liq separator gives different flows of the HC liquid and water when run with VLE and with VLLE Flash algortihm for the same amount of inlet wet gas flow (51948kg/h)
 with VLE - the HC liq  condensate flow is 10978 kg/hr (water flow is 0k/hr)
 but with VLLE- the water flow is 389 kg/hr and Condensate flow is 2985kg/hr 
 THE HYSYS output gives a HC liq condensate  flow of 3152kg/hr and water flow of 3152kg/hr.

Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Sameer Ningoo — Thu, 05 Dec 2019 11:26:53 -0000

1.The gas-liq separator gives different flows of the HC liquid and water when run with VLE and with VLLE Flash algortihm for the same amount of inlet wet gas flow (51948kg/h)
with VLE - the HC liq condensate flow is 10978 kg/hr (water flow is 0k/hr)
but with VLLE- the water flow is 389 kg/hr and Condensate flow is 2985kg/hr
THE HYSYS output gives a HC liq condensate flow of 3152kg/hr and water flow of 3152kg/hr.

With VLLE- the Separation gives a heat output of 1238KW? The input wet gas temp is 85--but the HC liq. condensate and water temp is 75C and output gas is 82C. Also the output gas has mixed phases and is not saturated. All input and output streams of separatro should have same temp like in HYSYS
With VLE Flash algoritm- the Separation gives the same heat output of 1238KW. The The input wet gas temp is 85--but the HC liq. condensate and water temp is 61C and output gas is 88C. Also the output gas has mixed phases(0.96 vapour). All input and putput streams of separatro should have same temp.

Have atached the DWSIM file.

Wet Gas separation: Different outputs with VLE and VLLE Flash algos.

Sameer Ningoo — Thu, 05 Dec 2019 11:26:53 -0000

Ticket 251 has been modified: Wet Gas separation: Different outputs with VLE and VLLE Flash algos.
Edited By: Sameer Ningoo (samningoo)
Description updated:
--- description-old

+++ description-new

@@ -1,4 +1,4 @@

-1.The gas-liq separator gives different flows of the HC liquid and water when run with VLE and with VLLE Flash algortihm for the same amount of inlet wet gas flow (51948kg/h)
+1. The gas-liq separator gives different flows of the HC liquid and water when run with VLE and with VLLE Flash algortihm for the same amount of inlet wet gas flow (51948kg/h)
with VLE - the HC liq condensate flow is 10978 kg/hr (water flow is 0k/hr)
but with VLLE- the water flow is 389 kg/hr and Condensate flow is 2985kg/hr
THE HYSYS output gives a HC liq condensate flow of 3152kg/hr and water flow of 3152kg/hr.