Walter W. Hellmuth

Refinery octane blend modelling using principal components regression of gas chromatography data

Abstract The use of capillary gas chromatography (g.c.) coupled with principal components regression (PCR) is shown to be an effective predictive tool for determining the octane values of gasolines blended from a wide variety of refinery streams. The linear combination of fuel stream g.c. data to give calculated blended fuel gas chromatograms and their associated octanes offers much promise for refinery blending optimization.

An easy sealing MAS rotor insert for liquids, gels, and air-sensitive solid samples

Recent attempts to seal MAS rotors for obtaining CP/MAS spectra of air-sensitive materials and/or liquids and gels have involved either heat sealing glass inserts (1, 2) or machining Kel-F inserts that require heat fusing a machined cap to the rotor top (3). Heat sealing of glass inserts presents problems when volatile solvents are used due to the proximity of the heat source to the sample (3). While easily machinable, the Kel-F inserts are not easily formed and sealing using a hot rod on the insert cap may not be complete. We report the design and use of a glass MAS rotor insert that uses an epoxy sealant, not heat sealing, and can be obtained commercially to fit a variety of rotor designs. Figure 1 shows that the Pyrex MAS rotor insert (Part No. SK-2 133, Wilmad Glass Co.) for the double-bearing Kel-F (Chemagnetics Inc.) rotors used in a M-100s 13C