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Chevron's ISO Processes

October 01, 2012
Jean Van Rensselar
Tip or Best Practice

Chevron’s ISO Processes 4

Chevron invented modern hydrocracking more than 40 years ago. Chevron’s all-hydroprocessing, iso-technology selectively concentrates and changes the molecular structure of wax into desirable isoparaffins. This allows refiners to maximize product yields and maximize product qualities. Chevron’s 3-step, iso-hydroprocessing route includes: ISOCRACKING, TM ISODEWAXING, TM and ISOFINISHING.TM

Chevron’s proprietary hydrocracking process, ISOCRACKING, improves VI by chemically converting low VI components to higher VI basestock. Unlike older solvent refining processes that produce raffinate5 and a highly aromatic, low-value extract, the byproducts of ISOCRACKING include valuable fuels such as gasoline and diesel. For feedstock, ISOCRACKING creates higher VI components and preserves more molecules in the basestock boiling range that solvent refining. This gives refiners the flexibility to produce a higher basestock yield for a specific VI or a higher product VI at an equivalent yield level. ISOCRACKING allows refiners to maximize feedstock flexibility and product performance.

ISODEWAXING (To Reduce Pour Point)
Chevron’s ISODEWAXING technology was commercialized in 1993. Unlike solvent dewaxing, which removes the wax, ISODEWAXING catalytically changes the molecular structure of the wax into isoparaffins. This results in high VI, low pour points and superior resistance to oxidation. It also preserves the basestock’s waxy-ness and produces higher product VI and/or higher yields than other dewaxing processes. ISODEWAXING accommodates a broader range of feeds, which can be processed into a broader range of products. Additionally, it can process feeds with close to 100% wax in a single process (without recycling unconverted wax). Refiners using ISODEWAXING produce basestock with a VI ranging from 95 to 140 and beyond. Pour points range from low (-9 C to -15 C) to ultra-low (<-40 C).

ISOFINISHING (To Improve Oxidation Stability and Color)
ISOFINISHING, which can be used as a stand-alone process, rounds out Chevron’s proprietary hydrofinishing technologies. In 1984 the company introduced hydrofinishing that uses noble-metal catalysts rather than base-metal catalysts. Noble-metal catalysts provide higher activity at lower temperatures than base-metal catalysts. This produces higher quality basestock. The higher activity allows refiners to operate smaller reactors at lower pressures for improved efficiencies. The color of the resulting basestock is also superior.

4. From http://www.chevron.com/products/sitelets/refiningtechnology/lube_tech3b.aspx
5. Raffinate is material that results from chemical or mechanical process after a desired chemical or material is removed. 


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