10 replies to this topic

[process_engg]

Hi,

 

I am working a project on condensate splitter which have 6 products LPG, light naphtha, heavy naphtha, Kerosene, heavy distillate, Atmospheric Residue. I have feed assay aslo with me,

 

I want to know how can I choose D86 cut point for thsese product. While searching the literature I found different cut point for same product in different books.

 

What would be the right approach? Is all product for condensate splitter being used for blending?

 

Please guide me.

 

Thanks, Please attach any document if you have related to condensate splitter topic.

 

Regards.

[Napo]

Process-engg,

You need to review about "atmospheric distillation" (topping), with this process you obtain the products that you describe.
Also you need to review the local regulations (standards) for every cut (product).
An old book about the distillation design is Petroleum Distillation Refinery of Watkins.

Napo.

[process_engg]

Hi Napo,

 

Thanks for your reply.

 

I have already gone through multiple text book. I already understood the process but have following doubts:

 

1) different books give different cut point for naphtha D-86?  which cut point should I select

2) I do understand that condensate splitter is a CDU type column only. I want to know in real condensate splitter plant what product they are generating and what product specification they are meeting for saleable product. In my case where we have selected 6 products, what project specification should i select to sale this product after condensate splitter (without having downstream unit)

 

1. LPG

2. Light Naphtha

3. Heavy naphtha

4. Kerosene

5. heavy Distillate

6. Atmospheric Residue

 

Regards,

[Napo]

Process-engg,

You need review the local standards of your country.

For the diesel you can review the ASTM D-975.

Napo.

[gegio1960]

"Condensate is a byproduct of natural gas production and the oil is processed at refining units to produce mainly naphtha, a petrochemical raw material." So, normally the residue product of a condensate splitter is a gasoil (ie cuts 4+5+6).

Would you kindly share the TBP of your condensate?

We can give more help about end point of naphtha if you give us more info. country? destination of naphtha (eg petrochemical, gasoline, further processing)?

good luck!

Edited by gegio1960, 03 August 2017 - 08:21 AM.

[colt16]

This is a very broad question and there is no such thing as a correct D86 temperature.

For the LPG it is straight forward, you want to cut it at C4 (light key) and C5 (heavy key).

For the Light and Heavy Naphtha, it depends on what you do downstream. Are they going to a petrochemical facility? For example, an aromatics production might want the C6-C10 range for the heavy naphtha, this would make the light naphtha C5-C6. Are they going to a Reformer for Gasoline blending? Some would leave out the C6 precursors that make benzene which is not allowed in gasoline these days. Without all these information it is impossible to say what you want.

For the Kerosene, generally you want to cut the D86 as high as possible until the kero freeze is around -47degC. Freeze that is lower than this is not allowed. Still this is not straight forward, because if you have some of the heavy naphtha drop down to the kero, you can also have a heavier D86 (in other words, a wider range). Hence distillation is largely optimized depending on the products you want.

For the Diesel, usually the Cold Flow properties will govern. Similar to kero, you would want to cut the D86 as high as possible until the Cloud Point or Cold Filter plugging point is limiting.

In short, you need to know your OBJECTIVES. That will optimize the column and the required D86 curves.

[Pilesar]

The choice of cut points is an economic decision. Products sell at different prices. The buyer and seller agree on the quality and quantity and price. The refiner determines which molecule goes to which product stream to maximize the total profit. Cut points for the column are not necessarily final product specifications, but a way to divide the molecules into different product streams. Usually, the refiner chooses to maximize the stream that pays the most, but that is not necessarily the solution that makes the most profit when all the product streams are included in the economic analysis.

[rdcrags]

I agree with Pilesar. An economic case study is the way to go.

[process_engg]

The choice of cut points is an economic decision. Products sell at different prices. The buyer and seller agree on the quality and quantity and price. The refiner determines which molecule goes to which product stream to maximize the total profit. Cut points for the column are not necessarily final product specifications, but a way to divide the molecules into different product streams. Usually, the refiner chooses to maximize the stream that pays the most, but that is not necessarily the solution that makes the most profit when all the product streams are included in the economic analysis.

Hi Do you have any specific document related to this topic then please share....!!!

[process_engg]

"Condensate is a byproduct of natural gas production and the oil is processed at refining units to produce mainly naphtha, a petrochemical raw material." So, normally the residue product of a condensate splitter is a gasoil (ie cuts 4+5+6).
Would you kindly share the TBP of your condensate?
We can give more help about end point of naphtha if you give us more info. country? destination of naphtha (eg petrochemical, gasoline, further processing)?
good luck!

Hi Gegio1960,
 
thanks for your rely. I am attaching the TBP curve. and location lets say USA. I want to know how do we select cut point, what approach we select.

 

 

Attached Files

•  TBP.png   23.98KB   1 downloads

[gegio1960]

just for an initial evaluation, looking at your condensate tbp curve, you could roughly obtain the following yields (%wt):

- gas: 2

- LPG: 5

- light naphtha: 8 (85)

- heavy naphtha: 50 (190)

- kero & gasoil: 25 (360)

- residue: 10

the figures in brackets are typical tbp cut points in °C.

you could start a process simulation (with hysys, proII....) with these figures and see the resulting astm d86 curves for the various products.

after that you should improve the simulation by comparing the results with the commercial specs of your final products...

Edited by gegio1960, 08 August 2017 - 08:45 AM.