What do Refiners do with Group I Oil

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Jul 4, 2002
Montgomery, AL
Johnny tells us that the major players in oil use Group II or Group II+ exclusively in thier dino now. Even the blends use Group II with Group III/IV in small amounts. Do refiners still have Group I oil to off load somewhere? Where does it go? Are any oil marketers using this group I?
Regarding Group II. Let us not forget that the original purpose of the Hydrocracking process was to enable refineries to process low quality crude and get sufficient recovery to make processing them economically feasible. It was NOT to just make better base oils. The folks who had access to high quality crude had no reason to switch to Hydro processing as solvent refining techniques already yielded very high quality base oils with good recoveries. That said, there are some good characteristics of Group I oils that can compliment the deficiencies of Group II oils. Yes, Group II's, III', have some deficiencies as engine oil lubricants. Just as Group IV (Pao's ) are supplemented with Group V oils (Ester), Mobil's Delvac 1300S as example, is actually a blend of Group II+ and Group I base stocks to fulfill very much the same properties as the PAO/Ester blend in full synthetic engine oil. Group II is extremely stable and as such can have additization suspension/fallout problems and does not have as high a natural detergency level as Group I oils. Group I has excellent natural detergency (like esters) and good additive solubility.. Thus by combining the two in the right proportion, one can achieve an oil with excellent additization hold, excellent cleanliness and all the advantages that Group II+ can yield. Your basic synergism.. Again, very much the same as synthetics are with their combination of PAO and Ester. Why doesn't everyone do it? Some companies do not have the capabilities to use both base stocks and only have one or the other product produced in house.. And then again there really are differences in oils, different manufacturing philosophies, different qualitiy levels, different applications. It is what makes oil so interesting and fun! George [ August 08, 2002, 09:43 PM: Message edited by: GeorgeCLS ]
GeorgeCLS, Thanks for lesson on oil! I had no idea Group I was a good detergent. Is that due to the more volatile short chain molecules? That would explain the higher Noack with those base stocks. I'm sure the idea above would be an oversimplification if correct. JJ
Regarding the short chain molecules (and shape), yes, you are correct! In PAO's case, as with Group II, the super stability is great in one aspect, a negative in another. Early PAO synthetics exhibited exactly the same problems as first generation group II mineral based had, one of which was additive fallout. Enter agressive ester, Group I and bingo, everything stays in solution just fine.. George Morrison, STLE CLS
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