The character and quality of process oils depends on how they are manufactured. In general, there are two manufacturing processes, the original solvent extraction process and modern hydroprocessing technology. The modern, all-hydroprocessing technology is more effective at lowering aromatic content, and the hydrocarbons remaining in the oil are much more stable than those in process oils produced using solvent extraction.

New all-hydroprocessing technology improves the quality of process oils. At its Richmond, California, refinery, Chevron operates the first all-hydroprocessing facility in the world for the manufacture of base oils and process oils. In hydroprocessing, undesirable components are converted to desirable and more stable molecular structures via saturation, ring opening and heteroatom removal. In hydrofinishing, the final stage of hydroprocessing, any remaining aromatics are hydrogenated, further improving oxidation stability and color. The result is Paramount and ParaLux – chemically pure, practically water-white, paraffinic process oils with exceptional color stability.

Today, performance specifications are being rewritten to reflect the superior properties of oils which have been all-hydroprocessed.