A good reference I have is 'Guide to Petroleum Product Blending'. It covers predicting many different properties of hydrocarbons when blending them. Octane is one of them and they include the effect of methanol and ethanol.
Two gasolinhe components rarely blend in a linear fashion. The reference that TD2K suggests will likely describe the bonus or debit that you get when two materials are blended.
If everything blended linearly, there wouldn't be a need for products such as WKBlend.
We are just now working on a change from MTBE to ETBE production, and we actually have a problem concerning EtOH in the product. It isn't in octane number, but in vapor pressure of the blend. Due to not fully understood interaction in the blend, its vapor pressure is lower than linear calculation suggests.
Keep this in mind when trying EtOH as blending component. Also remember that EtOH is hydrophilic, which is the cause many standards limit EtOH in Fuel Blends. Would absorb too much water for use as transportation fuel, especially when stored over time.
Bob,
I am pretty sure of this, as i have cross checked with Simsci and actual(physical operations in refinery). Well, this was done with all components of similar kinds of HC.
I am not sure whether Ethanol plus gasoline will behave in unexpected way than I discussed.
This is important to note that this is about RONC prediction.
I am sure that MON cannot be calculated in the way I described.
I would be delighted to now your opinion/comments on this and lokk forward to it.
Pro II will no doubt give an estimate of RON, but I'm not sure if it should be relied upon for an actual blending model. I'd tend to use ProII to identify an opportunity, then use actual test-run data to confirm if the opportunity really exists.
I also believe that you are correct when you state that certain components will blend linearly for RON...perhaps ones with the same type of molecular structure (makes sense to me). Most refinery streams have different PONA's though, so I wouldn't expect this to be a general rule.
Keep in mind that my hair is a lot greyer since I last worked as a blending Engineer...my memory could be getting weak.
Last weekend I downloaded a pretty comprehensive study report from Google titled 'Fuel specifications and fuel property issues and their potential impact on the use of ethanol as a transportation fuel' by Downstream Alternatives Inc. Perhaps may help you. If can't locate email me at steve@langleyventures.co.za and I'll forward pdf file to you - about 1.2MB.
