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Bulk Residence Time In Naphtha Cracking


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#1 mehul

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Posted 19 October 2018 - 12:25 AM

I have notice during simulation of Pyrolysis Furnace in Petrosim and VMG sim with increasing of bulk residence time , yield of Ethylene increase is it possible?



#2 Bobby Strain

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Posted 19 October 2018 - 09:09 AM

No.



#3 mehul

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Posted 19 October 2018 - 01:12 PM

Thanks for Replying , then what is the problems with the modeling.?? 



#4 Bobby Strain

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Posted 19 October 2018 - 02:07 PM

For models that are even close to reality you must pay a hefty price. Like TechnipFMC's Spiro.

 

Bobby



#5 mehul

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Posted 21 October 2018 - 01:02 AM

I Have Checked in Spyro same things Happened.

Residence time 0.287969

Summary wt% 
H2 0.943047
CH4 15.785
C2H2 0.32585
C2H4 27.786
C2H6 3.727
MAC 0.331634
PPD 0.221013
C3H6 13.879
Residence time s 0.255565
H2 0.926958
CH4 15.345
C2H2 0.324114
C2H4 27.6
C2H6 3.703
MAC 0.335917
PPD 0.223868
C3H6 14.315


#6 Bobby Strain

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Posted 21 October 2018 - 09:38 AM

You appear to be modelling an old furnace. And without further information, I agree with the results you present. This is very low severity operation, and not a modern furnace. Typical ethylene yield from naphtha is above 35 wt%.



#7 mehul

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Posted 21 October 2018 - 11:56 AM

Thanks For Your Response , Yes I further check my model and reconfigure its Radiant tube geometry and now it is exactly match i.e if i reduced residence time , mass % of ethylene Yield Increased

 

Residence time   0.3347                  0.3745
Property Mass Flows Mass Flows
Unit                   tonne/hr                    tonne/hr
Hydrogen 0.126494216        0.124871432
Nitrogen 0                    0
CO                                  0                    0
Oxygen          0                    0
Methane              2.339436892          2.264064622                                 P/E                     P/E
Ethylene              4.433405143          4.306722525                           0.490548091    0.528358875
Ethane                 0.553673784          0.559572123
CO2                              0                           0
H2S                               0                           0
Propene                 2.174798431 2.275495069
Propane                 0.04841153           0.051967224
i-Butane 0.008699009 0.009955046
i-Butene 0.273057638     0.291197418
1-Butene 0.14084377 0.152214155
13-Butadiene 0.550685279 0.552482937
n-Butane 0.011446496 0.013477239
tr2-Butene 0.060344688 0.064331101

Edited by mehul, 21 October 2018 - 12:09 PM.


#8 KHANFA

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Posted 24 August 2023 - 01:27 AM

Hi All,

need help to calculate the ultimate yield of ethylene without using Spyro or Coilsim?

 

Any help will be must appreciated.



#9 Pilesar

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Posted 24 August 2023 - 10:01 PM

See if you can find yield curves in the manuals from the furnace manufacturer. You might can interpolate gas cracking curves with good results. Naphtha cracking predictions will be difficult to get accurately.



#10 shvet1

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Posted 24 August 2023 - 11:35 PM

Is it a new installation or existing one? Pilot testing is implementing for such issues. You should contact a proven R&D center.



#11 KHANFA

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Posted 30 August 2023 - 07:03 AM

Is it a new installation or existing one? Pilot testing is implementing for such issues. You should contact a proven R&D center.

its a existing ethylene cracker, can share some literature if possible 



#12 KHANFA

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Posted 30 August 2023 - 07:04 AM

See if you can find yield curves in the manuals from the furnace manufacturer. You might can interpolate gas cracking curves with good results. Naphtha cracking predictions will be difficult to get accurately.

i was able to find the curves but they are qualitative & does not shows the COT correlation with conversion in wt% or mol%. 



#13 shvet1

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Posted 30 August 2023 - 07:24 AM

 

Is it a new installation or existing one? Pilot testing is implementing for such issues. You should contact a proven R&D center.

its a existing ethylene cracker, can share some literature if possible 

 

 

There was a pilot unit to test the feed of steam cracker at a process plant I had been working on. The same for other similar process units, e.g. propylene ammoxidation to acrylonitrile. There was a local R&D center for such issues.

 

For info - Any modern high capacity process other than very well known like crude oil distillation is science-intensive and require R&D some degree of before industrial implementation is applied. Otherwise a minor change/deviation from planned consumption/yield/quality entails a huge loss of operating profit. A couple days in successful operation of a steam cracker will bring more money than any R&D center is able to spend during a couple of years.
 
As per industry practice it is cheaper to conduct experiments/studies in lab scale than in industry one.

Edited by shvet1, 30 August 2023 - 07:28 AM.


#14 KHANFA

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Posted 31 August 2023 - 01:10 AM

 

 

Is it a new installation or existing one? Pilot testing is implementing for such issues. You should contact a proven R&D center.

its a existing ethylene cracker, can share some literature if possible 

 

 

There was a pilot unit to test the feed of steam cracker at a process plant I had been working on. The same for other similar process units, e.g. propylene ammoxidation to acrylonitrile. There was a local R&D center for such issues.

 

For info - Any modern high capacity process other than very well known like crude oil distillation is science-intensive and require R&D some degree of before industrial implementation is applied. Otherwise a minor change/deviation from planned consumption/yield/quality entails a huge loss of operating profit. A couple days in successful operation of a steam cracker will bring more money than any R&D center is able to spend during a couple of years.
 
As per industry practice it is cheaper to conduct experiments/studies in lab scale than in industry one.

 

Thanks for your feedback.






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