Because of low pressure & high temp of coking process (+950 C/1472 F) most of the VCM in green petroleum coke is mostly resid with some lighter components removed.
There was fairly good review of petcoke by API group for EPA which looked at petroleum coke for both Qualitative and Hazard focus for EPA on both green and calacined petcoke.
They confirmed it and Volatile material as non-hazardous (as it appears on all MSDS sheets) and both chemically & physically inert.
API’s PDF makes pretty good reference for lot cases – here was my old link to it :
http://www.epa.gov/hpv/pubs/summaries/ptrlcoke/c12563rr2.pdf
Because the Volatiles in petcoke is resid in nature and formed at high temp – measurments for vapor pressure, boiling point or vapor pressure are not going to produce any
meaningful data at ambient environmental conditions. The VM levels range from 9 to 21% and vary by the type petcoke your talking about : Delayed- Sponge/Shot/Needle, or Fluid/Flexicoke, and if it is green or calcined coke. The residum will be somewhat different due many different crude feedstocks that make up the resid components for the individual refinery & of course the variable operating conditions of temp/pressure/cycletime/coker design & technology employed ……. but when your looking at molecular soup we call resid and poly-methyl-chickenwire components the VCM is fairly uniform.
Regards & hope this helps