Chevron’s Salt Lake City refinery starts up ISOALKY unit

Chevron Corp. has completed the conversion of an existing 4,500-b/d hydrofluoric acid (HF) alkylation unit at its 58,000-b/d refinery in Salt Lake City, Utah, into the world’s first commercial scale alkylation unit based on ionic liquids alkylation technology licensed by Honeywell International Inc.’s UOP LLC (OGJ Online, Feb. 8, 2017; Oct. 4, 2016).

With commissioning and startup now completed, the unit is now equipped with the Chevron USA Inc.-developed ISOALKY alkylation technology, which uses a nonaqueous liquid salt, or ionic liquid, instead of HF or sulfuric acids as a liquid alkylation catalyst to produce a high-octane alkylate blending component that helps lower environmental impacts of gasoline, Chevron and UOP said on Apr. 13.

Alongside providing increased operating efficiency and feedstock flexibility, the ISOALKY retrofit also has enabled increased capacity in the unit, Chevron and UOP confirmed in an Apr. 12 press briefing on the sidelines of American Fuel & Petrochemical Manufacturers’ 2021 annual meeting.

Suitable for existing unit retrofits or new units, the proven technology also affords refiners process safety, performance, and economic advantages compared to conventional liquid acid alkylation technologies, as ionic liquids have strong acid properties that allow them to produce alkylate without the volatility of conventional acids, providing for simpler handling procedures requiring only standard personal protective equipment, UOP said.

Additionally, ionic liquids are regenerated on-site, eliminating any need for road or marine transportation for offsite regeneration and polymer byproduct handling.

Available for commercial licensing to help refiners meet rising global demand for cleaner-burning fuels at a lower cost and with simplified handling requirements, a series of ISOALKY technology unit revamps already is under way in North America, with additional units scheduled for startup in China as well, Chevron and UOP said.

While cost of the Salt Lake City unit retrofit remains confidential per Chevron policy, the operator said on Apr. 12 project cost is comparable to a unit revamp of any type. While it does require an investment, the payoff—including the boost in unit capacity, feedstock flexibility, and savings resulting from less complex handling procedures—more than justifies the capital expenditure.

Participants from Chevron and UOP on the Salt Lake City project and ongoing ISOALKY implementations at other sites added that project cost also remains highly region-dependent based on variables such as availability of materials, workforce, and logistics.    

While the companies disclosed no further details regarding specific North American and Chinese operators currently implementing ISOALKY technology, UOP previously confirmed a contract award from Sinochem Group affiliate Sinochem Hongrun Petrochemical Co. Ltd. for licensing of the technology at the operator’s 100,410-b/d refining and petrochemical complex in the Binhai Economic-Technological Development Area of Weifang City, Shandong Province, China (OGJ Online, Apr. 25, 2019).