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Operating Condition For Asphalt Production (Bitumen)

asphalt bitumen vacuum column vdc stripping steam viscosity ductility penetration

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#1 xpizarrov

xpizarrov

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Posted 19 April 2019 - 09:46 PM

Hi all!

 

I work as a crude unit process engineer. In our refinery, we are currently facing some problems in the asphalt (bitumen) production. As we are not an asphalt-dedicated refinery, we run time-fixed asphalt campaigns modifying the operating conditions of the vacuum distillation column (VDC). 

 

The adjustments are based on experience and something does not deliver the expected results. We set the vacuum fire-heater outlet temperature, stripping steam and some internal reflux in the slop wax section trying to reach 3 main asphalt properties (viscosity, penetration and ductility).

 

I could not find information regarding the relationship of these operating conditions and the properties mentioned above. So, would you be so kind to share information / experiences related this issue?

 

Many thanks in advance!!

 

 



#2 PingPong

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Posted 20 April 2019 - 06:47 AM

Is there no Bitumen Blowing Unit ?

 

If the desired asphalt properties must be delivered by the VDU alone, then there are several factors that would influence the required heater outlet temperature:

 

- the crude mix to the CDU,

- the TBP cutpoint of the AR from the CDU

- the operating pressure in the VDU

- the outlet pressure of the VDU heater

- steam quantity to heater and/or transfer line

- stripping steam to VDC bottom

 

There is no universal relationship between VDU heater outlet temperature and VR properties.

Obviously the crude(s) processed in the CDU/VDU have a big impact on VR properties.

 

I suggest you monitor the VR viscosity during asphalt operation and adjust operating parameters as required.



#3 xpizarrov

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Posted 20 April 2019 - 05:25 PM

Thanks PingPong!

 

We do adjustments to get an specific VR viscosity and we understand that penetration goes in the opposite way. However, we haven't figured out in which direction the ductility goes...



#4 Elaeslami

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Posted 08 November 2020 - 03:47 AM

As far as I know, higher rate of penetration in bitumen means lower viscosity. A bitumen with higher penetration index is softer and less viscose. For instance, the viscosity of bitumen grade VG 10 in the refinery is 800 poises, and its penetration is 80-100.

 

Attached File  Penetration-test-bitumen-procedure.jpg   43.39KB   0 downloads

 

Just like penetration and viscosity, ductility is an indicator of bitumen’s hardness. A bitumen sample that is less ductile will be hard and brittle. With an increase in viscosity, the ductility will decrease. For example, the ductility of VG 10 bitumen is normally 75 CM, but ductility for VG 40 bitumen is 25 CM.

 

Attached File  ductility1-1024x576.png   248.85KB   0 downloads

 

For a general understanding of bitumen production and details about operation, you can see this video about refined or petroleum bitumen as well. I hope it might help.

 

 

 






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