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Hysys - Configuration Of Distillation Column


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#1 alexandremt90

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Posted 22 September 2013 - 06:57 PM

Hello, everyone.

 

Does anyone know how, and if that would be possible, to use the inlet stream of a distillation column as the cold fluid of the condenser, i.e., the inlet stream would be pre-heated in the condenser before entering the column.

 

I tried to enter the column enviroment, but when I tried to replace the condenser by a heat exchanger, the following error appeared:

 

"Heat Exchanger is only supported when using Modified HYSIM I/O method within column sub-flowsheets"

 

Thanks!

 

 



#2 Padmakar Katre

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Posted 23 September 2013 - 03:26 AM

Hello,

This is typical configuration in refinery. Crude Main Fractionater overhead exchanges heat with crude feed (desalter upstream preheat network). Usual configuration is column feed-bottom at reasonable heat is available with bottom product. Configuration proposed by you is also not new and not impossible to have if it makes economic sense by doing so.

 

Now modeling this in Hysys is also possible. There are multiple ways you can reproduce the exact column configuration.

1. Use Modified I/O algorithm which supports mixer/splitter/vessels/heater/cooler/shell&tube heat exchanger/compressor/pump/valve operations.

2. Delete the condenser in column environment and replace with heat exchanger, make changes in necessary connections i.e. dis-connect the column feed and connect it to hx and then to column.

3. Make sure the column feed is a converged stream i.e. initially you can specify either of temperature/duty/vapor fraction for column feed stream

4. Based on the calculated duty, the column overhead vapor will receive the same duty. You can optimize with feasible approach and run the column.

 

Make the decision based on economic feasibility of the scheme.

Just a suggestion, search heat pump in Google and understand the concept. You can apply same concept here also i.e. compress the column overhead (usual routine is column overhead to a suction drum to De-entrain liquid droplets if any but in this case simulator gives you perfect vapors with no liquid droplets carried) and send those to feed-ovhd exchanger.

Good luck



#3 Fletch

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Posted 23 September 2013 - 11:34 PM

Another way to model it in HYSYS, within the column enivornment you can create a copy of an internal stream which is then exported to the main flow sheet, this then links the data from the column environment to the main flow sheet for you to use.

So you would make an "internal stream" of the stream to the condenser, hit export.

You now have a copy of the actual stream to the condenser which you can then put against your feed product in the exchanger.
You then set the outlet temperature of your condenser to that of your vapour product and you have modelled the condenser outside of the column.

You will likely need to slip in a recycle between your exported stream and the heat exchanger to allow it to solve.



#4 Padmakar Katre

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Posted 24 September 2013 - 12:12 AM

Hello,

I can tell you minimum 10 different ways to model here, but rather making you understand it will lead to confusions. Hysys is a wonderful simulator with too many options, only requirement is one needs to be an advance modeller. I have suggested only one option in previous post which I understand is easiest one.

Another easiest way is to link the energy stream of condenser to feed-ovhd exchanger and iterate with an Adjust operation. 



#5 alexandremt90

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Posted 24 September 2013 - 09:36 PM

Thank you all for the answers!

 

I succeeded to do this by using Modified I/O algorithm! I just wasn't finding where I could activate it, but now it's okay and my simulation converged. :)

 

It's nice to know that there a lot of other options too.



#6 Pallavi Kumari

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Posted 22 January 2015 - 09:08 PM

Hello,

This is typical configuration in refinery. Crude Main Fractionater overhead exchanges heat with crude feed (desalter upstream preheat network). Usual configuration is column feed-bottom at reasonable heat is available with bottom product. Configuration proposed by you is also not new and not impossible to have if it makes economic sense by doing so.

 

Now modeling this in Hysys is also possible. There are multiple ways you can reproduce the exact column configuration.

1. Use Modified I/O algorithm which supports mixer/splitter/vessels/heater/cooler/shell&tube heat exchanger/compressor/pump/valve operations.

2. Delete the condenser in column environment and replace with heat exchanger, make changes in necessary connections i.e. dis-connect the column feed and connect it to hx and then to column.

3. Make sure the column feed is a converged stream i.e. initially you can specify either of temperature/duty/vapor fraction for column feed stream

4. Based on the calculated duty, the column overhead vapor will receive the same duty. You can optimize with feasible approach and run the column.

 

Make the decision based on economic feasibility of the scheme.

Just a suggestion, search heat pump in Google and understand the concept. You can apply same concept here also i.e. compress the column overhead (usual routine is column overhead to a suction drum to De-entrain liquid droplets if any but in this case simulator gives you perfect vapors with no liquid droplets carried) and send those to feed-ovhd exchanger.

Good luck

Hi,

 

In your reply you have said that using Modified I/O algorithm mixer/splitter/vessels/heater/cooler/shell&tube heat exchanger/compressor/ pump/valve operations can be incorporated within column environment itself. I have ASPEN HYSYS7.3 and i able to find all unit in object palette of Modified I/O algorithm except compressor. Does this algorithm provide way to put compressor within column environment. Are there any other way to do the same. 

 

Thanks :)



#7 pavanayi

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Posted 23 January 2015 - 10:02 AM

Pallavi,

 

Why do you require a compressor model within a column environment? Why not just do it outside as the usual practice?

The more equipment you add within the column environment, the slower the solution converges. 



#8 sukanta87

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Posted 10 October 2015 - 12:40 AM

Hi,

 

Would you tell me where to find the modified I/O method or algorithm option in Hysys? Am using Hysys 7.2.

 

Regards



#9 sukanta87

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Posted 10 October 2015 - 12:51 AM

1. Click On the column so column property view window will be displayed
2. In the Parameters page click on the Solver button.
3. And from the Solver Methods option select Modified-Hysim Inside-Out option from dropdown list.
And then enter into the Column Envirnment.

 

Thanks Padmakar. I got it from one of your post.






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