11 replies to this topic

[Saidar]

Hello,

The project/simulation is done is Hysys.

I need help with an assignment that I received a while ago. Basically 5 crude assays were given, with their costs per barrel, and the products that needs to be produced, and the selling price of the products (see attaced for the assignment).

Using mass balances and solver in excel I came up with the ideal mixture(optimized for maximum profit) for 90% pure streams and 100% pure streams, 2 of the 5 crudes was selected, with volume flows of:

90% Conversion
Forcados: 570 414 barrels/day
Qua Iboe: 429 586 barrels/day

100% Conversion

Forcados: 546 284 barrels/day
Qua Iboe: 453 715 barrels/day

As I don't know yet how pure I will get the streams, I took the average of the 90% and 100% conversion for the crude stream.

Now, the difficult part that I'm struggling with is seperating the crude stream into the required products using a distillation column.

There are 5 products that need to be produced, along with the light and heavy components that cannot be sold. Altogether the distillation column needs to have 7 outlet streams. Thus 7 specifications is needed.

I have tried many times to simulate the column with the component flows (defining the component flows for each outlet stream, calculated theoretically), but the column will not solve in any way.

I need some advice regarding how to approach this problem, and how to design the column, how to column should look like, and what variables I should specify.

Any info on how to design a refinery in Hysys would be appreciated.

Please read the attached assignment if you need any additional info.

Thanks!

Attached Files

•  HYSYS+Projek+CEMI+322+2010.doc   92KB   147 downloads

Edited by Saidar, 31 August 2010 - 10:22 AM.

[Zauberberg]

Saidar,

The topic you have raised is too complex to be answered in the forum. It encompasses Crude tower design, various optimization techniques and, the most of all - how it should be executed for the real plant while not becoming a ridiculously expensive design/optimization solution, just because it results in marginal profit increase at the expense of huge additional costs.

At first, I would suggest you to take a look into the Hysys example showing CDU. Unless you are at least a little bit familiar with this subject, it will be an extremely hard task. Multiple draw-off towers are the most difficult to design and operate, although certainly not impossible. If you have time and opportunity, grab the books from Watkins (Petroleum refinery distillation) and Jones (Elements of petroleum processing). Some of the books from IFP can assist you as well.

Secondly, we cannot give you any comments on the model because you haven't uploaded it. There are many things you should pay attention at: crude characterization, the configuration of column (side draws, pumparounds etc.), side strippers, Naphtha fractionation.

There are several posts related to CDU design, troubleshooting, and optimization, in the ChE Forums. I remember a few of them because I had participated in those quality discussions we had. You can try exploring the forum history and look for similar threads. I'm sure you will find a lot of answers on your questions.

[Saidar]

Saidar,

The topic you have raised is too complex to be answered in the forum. It encompasses Crude tower design, various optimization techniques and, the most of all - how it should be executed for the real plant while not becoming a ridiculously expensive design/optimization solution, just because it results in marginal profit increase at the expense of huge additional costs.

At first, I would suggest you to take a look into the Hysys example showing CDU. Unless you are at least a little bit familiar with this subject, it will be an extremely hard task. Multiple draw-off towers are the most difficult to design and operate, although certainly not impossible. If you have time and opportunity, grab the books from Watkins (Petroleum refinery distillation) and Jones (Elements of petroleum processing). Some of the books from IFP can assist you as well.

Secondly, we cannot give you any comments on the model because you haven't uploaded it. There are many things you should pay attention at: crude characterization, the configuration of column (side draws, pumparounds etc.), side strippers, Naphtha fractionation.

There are several posts related to CDU design, troubleshooting, and optimization, in the ChE Forums. I remember a few of them because I had participated in those quality discussions we had. You can try exploring the forum history and look for similar threads. I'm sure you will find a lot of answers on your questions.

Hey,

Thanks for your reply... Yes I know this is very difficult project, I posted this question here out of desperation from my part hehe...

I don't really have a Hysys model at the moment because I don't know where to start with the distillation column. My knowledge in this field is basic at best. I know there is a column template in Hysys but it is way too confusing to modify it.

But thanks I will take a look on the forum and see if I can get some info on where to start.

Regards

[milenkom]

Saidar,

The topic you have raised is too complex to be answered in the forum. It encompasses Crude tower design, various optimization techniques and, the most of all - how it should be executed for the real plant while not becoming a ridiculously expensive design/optimization solution, just because it results in marginal profit increase at the expense of huge additional costs.

At first, I would suggest you to take a look into the Hysys example showing CDU. Unless you are at least a little bit familiar with this subject, it will be an extremely hard task. Multiple draw-off towers are the most difficult to design and operate, although certainly not impossible. If you have time and opportunity, grab the books from Watkins (Petroleum refinery distillation) and Jones (Elements of petroleum processing). Some of the books from IFP can assist you as well.

Secondly, we cannot give you any comments on the model because you haven't uploaded it. There are many things you should pay attention at: crude characterization, the configuration of column (side draws, pumparounds etc.), side strippers, Naphtha fractionation.

There are several posts related to CDU design, troubleshooting, and optimization, in the ChE Forums. I remember a few of them because I had participated in those quality discussions we had. You can try exploring the forum history and look for similar threads. I'm sure you will find a lot of answers on your questions.

Hey,

Thanks for your reply... Yes I know this is very difficult project, I posted this question here out of desperation from my part hehe...

I don't really have a Hysys model at the moment because I don't know where to start with the distillation column. My knowledge in this field is basic at best. I know there is a column template in Hysys but it is way too confusing to modify it.

But thanks I will take a look on the forum and see if I can get some info on where to start.

Regards

Hmmm I remember seing somewhere on internet, detailed simulation of crude oil distillation in Aspen and Hysys as well if I'm not mistaken. It might be usefull to go through that first and that try again at your simulation. I'll have a look if I can find something on net. I remember I found that area interesting as I myself have never done this example. But it showed detailed approach on how to define assay in Aspen. I might try that one myself in the near future as soon as I will have some spare time.

Edited by milenkom, 31 August 2010 - 05:04 PM.

[milenkom]

Actuall I found the file on my flash drive. It's simple process of oil distillation, which gives you step by step explanation of petroleum distillation in Aspen Plus (Crude fractionation example).
Bad news is this for Aspen Plus. For me this generally wouldn't be a problem since whatever I can do in Aspen, I would probably know how to repeat in Hysys as well. Hope it helps, I'll have a look whether there's anything available for Hysys as well.

Attached Files

•  AspenTech-Petroleum.pdf   1.27MB   401 downloads

Edited by milenkom, 31 August 2010 - 05:26 PM.

[milenkom]

There's also one example of designing Crude Oil Tower in Hysys in attached documents. It's in separate chapter detailing design of crude fractionation train including pumparound streams as well as draw off towers.  TutAppsHY3.pdf   5.24MB   375 downloads

[Saidar]

There's also one example of designing Crude Oil Tower in Hysys in attached documents. It's in separate chapter detailing design of crude fractionation train including pumparound streams as well as draw off towers.  TutAppsHY3.pdf   5.24MB   375 downloads

Milenkom, you are the best! Thanks! I will work through those tutorials and see what I can come up with. Also I have found this diagram of a typical crude tower in a book that I'm going to work off... (see attachment)

Again everyone thanks for your help

Attached Files

•  Crude Tower.jpg   213.26KB   85 downloads

Edited by Saidar, 01 September 2010 - 05:52 AM.

[Saidar]

There's also one example of designing Crude Oil Tower in Hysys in attached documents. It's in separate chapter detailing design of crude fractionation train including pumparound streams as well as draw off towers.  TutAppsHY3.pdf   5.24MB   375 downloads

Hey, the Hysys tutorial document is corrupted can you please upload it again ?

Thanks!

[milenkom]

It takes quite a while to upload it from site, maybe that was the cause for corruption. I'm giving you direct link instead.

http://archivos.labc.../TutAppsHY3.pdf

Best of luck

Milenkom

Edited by milenkom, 01 September 2010 - 01:04 PM.

[Padmakar Katre]

Hello,

The project/simulation is done is Hysys.

I need help with an assignment that I received a while ago. Basically 5 crude assays were given, with their costs per barrel, and the products that needs to be produced, and the selling price of the products (see attaced for the assignment).

Using mass balances and solver in excel I came up with the ideal mixture(optimized for maximum profit) for 90% pure streams and 100% pure streams, 2 of the 5 crudes was selected, with volume flows of:

90% Conversion
Forcados: 570 414 barrels/day
Qua Iboe: 429 586 barrels/day

100% Conversion

Forcados: 546 284 barrels/day
Qua Iboe: 453 715 barrels/day

As I don't know yet how pure I will get the streams, I took the average of the 90% and 100% conversion for the crude stream.

Now, the difficult part that I'm struggling with is seperating the crude stream into the required products using a distillation column.

There are 5 products that need to be produced, along with the light and heavy components that cannot be sold. Altogether the distillation column needs to have 7 outlet streams. Thus 7 specifications is needed.

I have tried many times to simulate the column with the component flows (defining the component flows for each outlet stream, calculated theoretically), but the column will not solve in any way.

I need some advice regarding how to approach this problem, and how to design the column, how to column should look like, and what variables I should specify.

Any info on how to design a refinery in Hysys would be appreciated.

Please read the attached assignment if you need any additional info.

Thanks!

Dear,
From your problem statement it seems the problem related to Aspen-PIMS i.e. the refinery configuration through Linear Programming and Hysys will come into picture in the later stage.

[Saidar]

Ok I have come very far with this project, at the moment my main problem is my reflux ratio. I'm struggling to get it below 35. Any idea how to lower the reflux ratio of a tower ?

[ahsan waqar]

hello saidar...
I am a student of final year chemical engg. We have to done a group project to apply our knowledge what we have learnt. Our supervisior has assigned us a design case of CRUDE DISTILLATION UNIT.
Do me a favour, provide me your distillation column designing calculations, so we can easily understand the path and approach from your solved manuals.
I will feel lucky to get some hope full rply from you...