Dewaxing Process by Chevron Lummus Global LLC

Application: Selectively convert feedstock’s waxy molecules by isomerization in the presence of ISODEWAXING Catalysts. The high-quality products can meet stringent cold flow properties and viscosity index (VI) requirements for Group II or Group III baseoils.

Description: ISODEWAXING Catalysts are very special catalysts that convert feedstocks with waxy molecules (containing long, paraffinic chains) into two or three main branch isomers that have low-pour points. The product also has low aromatics content. Typical feeds are: raffinates, slack wax, foots oil, hydrotreated VGO, hydrotreated DAO and unconverted oil from hydrocracking.

As shown in the simplified flow diagram, waxy feedstocks are mixed with recycle hydrogen and fresh makeup hydrogen, heated and charged to a reactor containing ISODEWAXING Catalyst (1). The effluent will have a much lower pour point and, depending on the operating severity, the aromatics content is reduced by 50– 80% in the dewaxing reactor.

In a typical configuration, the effluent from a dewaxing reactor is cooled down and sent to a finishing reactor (2) where the remaining single ring and multiple ring aromatics are further saturated by the ISOFINISHING Catalysts. The effluent is flashed in high-pressure and lowpressure separators (3, 4). Small amounts of light products are recovered in a fractionation system (5).

Yields: The base oil yields strongly depend on the feedstocks. For a typical low wax content feedstock, the base oil yield can be 90–95%. Higher wax feed will have a little lower base oil yield.

Licensor: Chevron Lummus Global LLC.