Consequence modelling using DNV PHAST - Non stabilized ''black crude oil''

[billdoor]

Hello All !
Can someone show me the best way to simulate consequence effects (JET FIRE/POOL FIRE...) with DNV PHAST in the case of a fluid which is a non-stabilised crude oil categorized as ''black oil'' downstream of wellhead and flowing through flowlines, manifolds, trunklines and so on...
The Use of DNV-phast MC (multicomponent) is limited to a mixture of a maximum of 18 pure components. Our mixture (non-stabilised crude black oil) contains more than 40 pure components.
Your cooperation is very much appreciated.
Thank you

 

[georgeverghese]

Typically this is done by lumping all components C8(say) and larger into C8. If components C8 smaller is more than 18 components, then lump all C7 and larger into C7.

 

[ProSafPlant1]

I used to follow this 2001 table from Shell FRED software, unless I had more specific data, then would group the largest% components similar to georgeverghese reply. The fire modeling results for a specific configuration of pool fire or jet fire don't vary much by specific component of the heavier fractions.

 

[1503-44]

That looks fine for everything except crude oil.
Crudes vary widely. An analysis is absolutely necessary,
Its no longer 2001 - Some "crudes" these days are more gasoil than crude.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[billdoor]

Thank you all for your prompt responses

Thank you Georgeverghese for your prompt response !
By lumping all components C8 and larger into C8, the software will display conservative consequence effects results for jet fire and flash fire but the software will not generate any results for pool fire even if we all know that pool fires are a fact in past crude oil facilities major accidents. Do you have a rule of thumb or a mean to come up with conservative values regarding black crude oil
pool fires consequence effects results in such a case. The black oil composition is displayed below.

My Thanks to ProSafPlant1 and 1503-44 for the table, advices and comments.
1503-44 is absolutely right to say that some "crudes" these days are more gasoil than crude. Below is a rough composition of our black oil:

C1: 37% (MOL)
C2: 13% (MOL)
C3: 09% (MOL)
C4: 05% (MOL)
C5: 04% (MOL)
C6: 03.5% (MOL)
C7: 03.5% (MOL)
C8: 04% (MOL)
C9: 03% (MOL)
C10: 02% (MOL)
C11: 02% (MOL)
C12+: 14% (MOL) / C12+ Estimated Density: 0,86 / C12+ Molecular Weight: 282 / C12+ wt% : 49%

Thank you again !

 

[ProSafPlant1]

Depending on what purpose for the modeling, have you tried the standalone model for pool fire, inputting a specific spill diameter, e.g. storage tank diameter, containment area diameter, or design fire area such as for a fireproofing spec.

Have you tried a different orientation of the leak, e.g. downward to create a pool? If directed upwards at high pressure, it's possible no ground pool with flammable vapour forms.

There used to be a PHAST user group somewhere.

 

[georgeverghese]

It sounds like these consequence results for pool fire you're looking for now are not related to composition, but to some other input parameters in the model you have built - what little I know on this topic is from the few times I ran SHELL - FRED some 20years ago. A lot may have changed since then, and the level of detail you're looking at now was then process safety / technical safety engineer specialist skillset - well beyond me.

 

[1503-44]

Natural gas, natural gasoline and fuel oil?

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[billdoor]

Thank you all for your tips and advices , I appreciate !
You bet it right on the nail ProSafPlant1 ! As we would like to come up with recommenfations regarding equipment spacing and fireproofing spec. I will run the software in the light of your remarks (standalone model for pool fire, downward relase orientation).
Thank you again.

 

[ProSafPlant1]

Billdoor, you might find this plotting of PHAST data for fireproofing interesting:

 

[billdoor]

This will be of a good help.
Thanks a lot ProSafPlant1 !

 

[Rafik5582]

Thank you all for the very informative discussion
ProSafPlant1 could you possibly give me the reference from which SHELL FRED document you got that table from ill very much appreciate it.
Also whe do you guys suggess for the more light type crude oils like the Algerian Brandt.
Have a great day

 

[LittleInch]

Rafik,

you seem to looking at well fluids with that composition. Nearly 65% of it will instantly vapourise if it comes out of the pipe so there's not much left to create a pool fire as the jet fire will be much much bigger.

What the stabilised crude looks like can be quite different to what the well fluids are.

I would almost say what you have there isn't crude oil but more like a wet gas field / gas condensate.

What's the GOR or CGR?

There's always a debate about when is is an oil field with some gas and when is it a gas field with some liquids.

Over time, especially with gas reinjection, the field can actually change from an oil field ion early life to a gas field in later life.

One "oil" field I was working on started at <2000 scf/bbl but then went up to over 20,000.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Rafik5582]

Thank you littleinch for the informative responce i really appreciate it
To put things into contexte, im working on a refinery safety study, these type of studies require consequence modelling of the differente phenomenas that could happen (fires, explosions ..etc.)
so in order to do that i need to model ther different refining products(naphtha, crude oil, kerosene ..etc), having an exact idea of the composition isn't feasible so i was looking for a document that gives a simple and conservatif composition of these products.
ProSafPlant1 gave a very interesting screen shot and im looking for the full document
Thank you again

 

[1503-44]

Ranges of carbon number compounds of the various products
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1689253950/tips/products_carbon_number_range_c5yryf.bmp[/url]
consider the ranges defined by the arrows shown on the composition graph to represent a normal curve of C_no compositions from min to max carbon numbers.
like this

The C_no compounds

~Atttached file shows various chromograph compound compositions for several products

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1689254916/tips/aviation_gasoline_vzaftu.bmp[/url]
is that what you needed?

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."