HYSYS Topping unit distillation crude
HYSYS Topping unit distillation crude
(OP)
Hello everyone:
I simulate topping unit where in current operating conditions. After reconstituting the oil improve the simulate data. But I do not matches the pour point of diesel.
The pour point (API 1974) is -8 ° C and should be 0 ° C.
Urgent need that this simulation is as real as possible because I have design a simple vacuum flasher to recover the diesel that is lost as reduced crude.
Attached is my simulation.
Hopefully someone can help me, my mind is somewhat blocked.
The product specifications are as follows:
Naphta:
API:65,2
Kerosene:
API: 46,8
Flash Point °C: 42
Freeze Point °C: -50,2
Diesel:
API: 38,2
Flash Point °C: 79.
I simulate topping unit where in current operating conditions. After reconstituting the oil improve the simulate data. But I do not matches the pour point of diesel.
The pour point (API 1974) is -8 ° C and should be 0 ° C.
Urgent need that this simulation is as real as possible because I have design a simple vacuum flasher to recover the diesel that is lost as reduced crude.
Attached is my simulation.
Hopefully someone can help me, my mind is somewhat blocked.
The product specifications are as follows:
Naphta:
API:65,2
Kerosene:
API: 46,8
Flash Point °C: 42
Freeze Point °C: -50,2
Diesel:
API: 38,2
Flash Point °C: 79.





RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
The only way to have good data passes from the lab.
Some lab data can be managed for interpolation and "narrow" extrapolation by means of a good CAM (Crude Assay Management) software.
Good luck
RE: HYSYS Topping unit distillation crude
If you know properties for each fraction, and if you know blending formulas, you could try to set up your own calculator routines in the simulator to estimate these.
RE: HYSYS Topping unit distillation crude
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
At the top and bottom temperature are out of range (a little..)
Calculate the freeze point of kerosene and adjusted to reality (-48°C from -50°C). But, not if my simulated diesel resembles the real diesel.
Shipping excel with a comparison D86 real v.s D86 from Hysys.
I have no experience simulating crude distillation it is part of my thesis
any suggestions are welcome.
If someone could check my simulation really appreciate it
Thank you very much
RE: HYSYS Topping unit distillation crude
1) Insufficient/incomplete characterization of crude oil - plug more data from Crude Assay in the Oil Manager;
2) Software deficiencies (as mentioned above) - can be somewhat combated against if you can fulfill the item No.1;
3) Insufficient separation between Diesel and Reduced Crude - try adding more trays between the Diesel draw-off tray and the flash zone, increase heater temperature, add more stripping steam.
When posting simulation models please save them as XML files so they can be opened in earlier versions of Aspen.
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
But before we can design the "Torre de repaso" i need an a good simulation of actual situation the topping.
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
Regards
RE: HYSYS Topping unit distillation crude
Are you simulating an actual, existing column, or this is a project/student work? I find it hard to believe that there is a CDU column anywhere in the world with such draw-off arrangements.
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
Believe it or not it works well here lol.
Do you need data to help me?
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
Your model shows 11 trays only which is FAR too less for any CDU column.
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
Reflux Return: 1
Kero Draw: 7
Diesel Draw: low the Packing Bed, 17 tray.
Zona Flash: Mellapack, (18-19-20)
Crude Feed: up tray 21 (20)
Stripping Reduced Crude: 21-22-23-24
(page 1)
RE: HYSYS Topping unit distillation crude
Wash zone seems to be equivalent to 4 theoretical trays and assume the P/A packing equal to 3 theoretical trays. Then rerun the model.
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
Many thank you very much.....hopefully converges me
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
Another thing is the way you mixed the column feed - it doesn't look good. You have generated the feed by re-mixing of all the products (which is in principle OK) but then you added almost 50% of the flow, coming as another Crude oil stream. Why is that so?
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
Only I have the characterization of two raw(I could not get more because they must ask at an external laboratory).
These crudes are:
CRUDO X
CRUDO Y
CRUDO X, its 35% of feed and CRUDO Y its 1% of feed. Of these crude i have a TBP, API and viscosity.
What I did was reconstitute the remaining 64% of feed.
The yield od the products its:
Naphta: 20%
Kero: 15%
Diesel: 20%
Reduced Crude: 45%
Then the flows are approximate:
CRUDO X: 849 m3/d
CRUDO Y: 24
NAPHTA: 310.6
KERO: 232.95
DIESEL:310.6
REDUCED CRUDE: 698.85
I request ASTM D86 of the oil fed to the plant (mixture of many things) and add it to food with flow 0 m3/d.
What would you??
Regards
RE: HYSYS Topping unit distillation crude
A useful tip: never specify properties and yields of a product at the same time. In simple words, if you want to produce e.g. 30 m3/h of Diesel, don't specify 95% D86 or Pour Point of Diesel if you have specified the flow/yield already. Property is a direct function of draw-off rate so if you are forcing software to match both criteria, it will likely fail to converge.
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
Then keep the characterization as is.
RE: HYSYS Topping unit distillation crude
H E L P
RE: HYSYS Topping unit distillation crude
I think your column cannot converge because of inability to perform T-P flashes. You can see that from the phase envelope - it is a single straight line (like a pure component). This needs to be fixed.
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
Has you a reference picture as it should be that curve?
Regards
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
There needs to be a clear 2-phase region in the phase envelope. See examples for different types of oil/fluids: http://www.fekete.com/SAN/WebHelp/FeketeHarmony/Ha... and https://www.metu.edu.tr/~kok/pete110/PETE110_CHAPT...
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
CRUDO X: 50% date: TBP - API - Viscosity
CRUDO Y: 50%: TBP - API - Viscosity
a total 2650 m3/d (april average).
The result is far from the actual (Cold properties product - T Condenser - T tope - T bottom - D86 HYSYS v.s Lab)
Which is the reason this BIG difference? A master phase envelope? Do not generate the bubble point line, i don´t know why.
can you advise me?
Regards
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
- I've changed the fluid package model to SRK. It yields more accurate results sometimes. Now the crude oil phase envelope looks more realistic.
- I managed to obtain desired product properties (speaking of D86). Targeting IBP or FBP can lead to larger errors. That is why 5%, 10%, 90%, and 95% D86 are more commonly used.
- By matching properties, there aren't many degrees of freedom to play with the flows/yields. Naphtha cut point is determined by the tower top temperature, so if you want to match the cut point (lets use 90% D86), then you have to leave the simulator to calculate the flow. There is more room to play with Diesel and Kero, but ultimately the combined yield of these two products will be more or less constant if you have fixed the product properties.
- Diesel stream has a very low flash point. Is there any stripping steam at all? A good practice is to leave steam control valves on manual, not on automatic - especially if meters are not calibrated regularly.
This is certainly more closer to reality but hard to say whether it is decently away from reality, or not. I would have to see the plant and look into operating parameters myself. Also, remember that for producing a quality model not only the feed should be characterized properly, but also the instruments and meters around the column need to be zeroed and calibrated. What they are showing currently does not necessarily need to be true.
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
I worked all day in the simulation,followind your advice. Finally arrive at more realistic results (envelope phase and operating parameters).
These are the actual data:
PRODUCTION m3/d
NAFTA: 570
KERO: 450
DIESEL: 520
CRUDO REDUCIDO: 1110
FEED TO PLANT: 2650
PROPERTIES:
NAFTA KEROSENE DIESEL
63.36 °API 47 °API 38.08 °API
ASTM D86 °C Flash point 41°C Flash Point 79 °C
0% 38 Freeze Point -51 °C Pour Point -6 °C
10% 69 ASTM D86 °C ASTM D86 °C
50% 101 0% 147 0% 179.3
90% 129 10% 165 10% 225
100% 161 50% 192 50% 274
90% 230 90% 316.3
100% 256 100% 340
In EXCEL attached plant data.
I have 3 simulation with different convergence and tray distribution.
My problem is that I have result in very light products (sim 17-sim 18) and very heavy products (sim 19, especially naphtha)
I need to prioritize a realistic result for diesel and naphtha, because i need simulate a splitter of nafta and a vacuum column to recover diesel from reduced crude.
I'm stuck in the simulation of topping, please help.
By the way do you have information to simulate HYSYS a vacuum tower? Because I have no idea how to do it(....for now). I never simulate a vacuum tower.
Hopefully you can help, I owe you a beer.
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
NAFTA KEROSENE DIESEL
63.36 °API 47 °API 38.08 °API
ASTM D86 °C Flash point 41°C Flash Point 79 °C
0% 38 Freeze Point -51 °C Pour Point -6 °C
10% 69 ASTM D86 °C ASTM D86 °C
50% 101 0% 147 0% 179.3
90% 129 10% 165 10% 225
100% 161 50% 192 50% 274
90% 230 90% 316.3
100% 256 100% 340
Sorry for this
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
If you have obtained decently accurate simulation model (in terms of product yields and properties), that's a pretty good start. I would not bother with cold properties if you managed to match the yields and distillation cuts. Hysys isn't so good in predicting cold properties, as mentioned by others in this thread.
As for the vacuum distillation simulation, remember to use Brown K10 or Esso K thermodynamic package. I think there should be a simulation template/sample on Vacuum distillation in Hysys files - you can start from there. I am attaching one paper of oil characterization, and below is the link for Aspen property packages.
Good luck.
http://sites.poli.usp.br/d/pqi2408/bestpracticesop...
Dejan IVANOVIC
Process Engineer, MSChE
RE: HYSYS Topping unit distillation crude
paulinabarrientos.s@gmail.com
RE: HYSYS Topping unit distillation crude
I´m tunning my simulation and I originated a question. Is there a problem if the number of theoretical trays exceeds the number of actual tray??
Regards
RE: HYSYS Topping unit distillation crude
good luck
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
RE: HYSYS Topping unit distillation crude
According to their work experiences, what are the requirements of REDUCED CRUDE to be treated in a SIMPLE VACCUM FLASHER?? (heavy metals,sulfur,etc etc etc...any requirement that you know.
Thank you very much for your attention
RE: HYSYS Topping unit distillation crude
Here is Aspen/ Hysys for future related questions- put such a thread either in this or that forum.
http://www.eng-tips.com/threadminder.cfm?pid=137
http://www.eng-tips.com/threadminder.cfm?pid=1529
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