7 replies to this topic

[fifi]

Hi everyone,
Please can anyone advise how to simulate side draw as a feed to the column in Hysys, as when you try to connect the side draw as Feed, it doesnt read the stream properties and the whole column gets unconverged.
Actually this is a general issue, if you want to feed back a stream in the Proecss, how it should be done as Hysys does not recognise that stream and losses all stream data from the starting point as soon as you put a stream back in the system and also shows some 'Inconsistency message' cheers

[abhi_agrawa]

Fifi,

I think that you need to use the recycle block for this.

abhishek

[joerd]

If you have a pumparound (which it sounds like) you need to use the pumparound page of the distillation column dialog. Also check out the manual, it is pretty comprehensive.

[Padmakar Katre]

Dear,
Please could give some further highlights on what is the actual issue. As its not clear as it's a Pump around or something else. One thing keep in mind to Run any column all the feeds to the columns should be converged streams and all required data input should be given to the column. Please let us know the purpose of that stream which you are withdrawing as a side cut from the column andputting it back to the column. Does that stream get further treated and then sent back to the column please its not clear. Waiting for further clarifications from your side.

[fifi]

Hello,

Actually I have a distillation column and the overhead stream is to be condensed, pumped and some %age of the pumped liquid is to be sent back to the column as Top feed stream. As to converge the column all the feed streams to the column must be already converged, I can not converge the column if I dont specify the pump discharge stream. and by specifying the pump discharge stream, it shows inconsistency message in the stream and can not converge...
so anyone can please guide how to simulate the column overhead that is sent back to the column as reflux stream after condensation???

Thanx

[joerd]

What you have is a straightforward distillation column. When you place the distillation column on the Hysys PFD, the system sets everything up for you. You only have to attach the net product streams and duty streams, specify the condenser type (partial, full reflux, partial reflux), and specify the column pressures. Hysys will then create a distillation column that includes the reboiler and the overhead system automatically. This is the easiest way to get quick and robust convergence, and is well described in the Hysys Operations manual.
You can see what Hysys created by going into the Column environment, then you see the tray stack, a kettle reboiler, and an overhead separator with a duty stream, which represents the condenser, reflux drum and pump.
If you want to model the overhead system in detail, a convenient way is to export the overhead vapor stream to the main flowsheet, and then create a cooler, separator, and pump. The exchanger should have the same duty as the column top duty stream, and the product streams should be the same as the column product streams.

[fifi]

Thanks

What you have is a straightforward distillation column. When you place the distillation column on the Hysys PFD, the system sets everything up for you. You only have to attach the net product streams and duty streams, specify the condenser type (partial, full reflux, partial reflux), and specify the column pressures. Hysys will then create a distillation column that includes the reboiler and the overhead system automatically. This is the easiest way to get quick and robust convergence, and is well described in the Hysys Operations manual.
You can see what Hysys created by going into the Column environment, then you see the tray stack, a kettle reboiler, and an overhead separator with a duty stream, which represents the condenser, reflux drum and pump.
If you want to model the overhead system in detail, a convenient way is to export the overhead vapor stream to the main flowsheet, and then create a cooler, separator, and pump. The exchanger should have the same duty as the column top duty stream, and the product streams should be the same as the column product streams.

[NGL Licensor]

Thanks



Salam,

Fifi, did you manage to converge? Believe above posts provide the solutions

If not, send me the stream composition and will take it step by step

Regards,
A.King

What you have is a straightforward distillation column. When you place the distillation column on the Hysys PFD, the system sets everything up for you. You only have to attach the net product streams and duty streams, specify the condenser type (partial, full reflux, partial reflux), and specify the column pressures. Hysys will then create a distillation column that includes the reboiler and the overhead system automatically. This is the easiest way to get quick and robust convergence, and is well described in the Hysys Operations manual.
You can see what Hysys created by going into the Column environment, then you see the tray stack, a kettle reboiler, and an overhead separator with a duty stream, which represents the condenser, reflux drum and pump.
If you want to model the overhead system in detail, a convenient way is to export the overhead vapor stream to the main flowsheet, and then create a cooler, separator, and pump. The exchanger should have the same duty as the column top duty stream, and the product streams should be the same as the column product streams.