Combustion Chemistry

[GCR_VE]

I read par. 3.1 of Technical Reference Guide (v.7) and make many simulations with fuel molecule C25 H42 O6 N2 (cellullose material as in Allfire.in). My input yield of CO is 0,10 kg/kg and for Soot is 0,07 kg/kg (pre-flashover). I have never seen HCN in output.

I have only basic knowledge of chemistry so my wonder is: fuel molecula have many atoms of H and of C, air have 78% of N then I think that reaction can produce enough HCN that non zero values in output can be present.

My idea is only qualitative. 

I am wright or there is some bug in my argumentation ?

I am doing wrong simulations, wrong input ?

 

GCR

[GCR_VE]

I correct my mistake: molecole that I have used for cellulose is: C6 H10 O5. So there no N in material to burn but air have a great quantity of N.

Therefore, the arguments remain the same.

GCR

[Richard Peacock]

This is as expected.  The Nitrogen in air, bonded together as N2, is far more stable and far less reactive than the typical Nitrogen ion in a fuel.  In CFAST, we assume that HCN is only generated from that contained in the burning fuel.  The Nitrogen in the air is simply considered an inert molecule that is accounted for in the overall mass balance, but that does not take part in the simplified combustion reaction in CFAST.

[GCR_VE]

ok, I agree (I read also my old chemistry books).

Now I need to put HCN in Cfast input for FED calcullatio as in ISO 13571. 

I think to use TS input that is a value in kg/kg.

I am not able to make a chemical/statistical analisys of materials in my space (an office building) so I think to use data from cap. 62 and 63 of SFPE Handbook 2016. This book give a lot of numbers, that I have read. 

I have mainly office furniture (wood coated with melamine laminate), papers, books, office chairs with padded seat on plastic construction.  

I think that a value between 50 and 100 ppm (to convert ....) can be not too litlle but not too high.  

Someone have some statistical data for offices in Europe (in Italy) ?

Thank you.

GCR

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