US Chevron Starts Up New Salt-based Alkylation Unit From Honeywell

US Chevron Starts Up New Salt-based Alkylation Unit From Honeywell

HOUSTON (ICIS)--Chevron started up a revamped alkylation unit that relies on Honeywell UOP's process technology based on a salt instead of hydrofluoric acid (HF), the companies said on Tuesday.

The revamped unit is at the company's refinery in Salt Lake City, Utah. Chevron and Honeywell did not disclose the capacity or the cost.

Alkylation units use isobutane and olefins to produce alkylate, a high-octane gasoline blendstock.

Chevron chose to revamp the alkylation unit at Salt Lake City because it would provide the company with a test to see if it could successfully retrofit an existing plant, said Mike Coyle, president of Chevron Manufacturing. Plus, the project would reduce risk at the refinery by eliminating the use of hydrofluoric acid.

Hydrofluoric acid has been at the centre of many refinery fires and accidents over the years. An explosion at a refinery in Philadelphia was caused by a ruptured pipe that released more than 5,000 lb (2,300 kg) of the acid. Over the years, hydrofluoric acid has attracted the criticism of a labour union and the attention of environmental groups.

Some refineries have used sulphuric acid instead. But Honeywell's process technology, called ISOALKY, does not rely on any acid for a catalyst. Instead, it uses a non-aqueous liquid salt. This removes the risks involved with handling large amounts of acid.

As a result, the process technology does not require any special personal protective equipment (PPE) beyond what is standard for refineries, the companies said.

The process technology should benefit from the trends that are causing demand for alkylate to grow faster than that for gasoline.

Countries around the world are adopting stricter sulphur regulations for gasoline. The process that refiners use to remove sulphur from gasoline lowers its octane rating. Alkylate has almost no sulphur, and its high octane rating offsets the reduction caused by the removal process.

"Alkylate is probably the most highly sought-after blendstock that people are looking for today," said Bryan Glover, CEO of Honeywell UOP. He expects new alkylation units will be build in China, other parts of Asia Pacific, Africa and even Latin America. Gasoline demand is still rising in these parts of the world.

Already, Sinochem Hongrun Petrochemicals will use ISOALKY at its complex in China, according to Honeywell.

Revamps could take place in North America and Europe among refiners that want to expand, update or modernise existing alkylation units, Glover said.

A lot of these units were built several years ago, which limits the ability of refiners to expand them without replacing the existing process technology, he said. By expanding alkylation capacity, refiners that export gasoline can produce material that can meet the stricter fuel standards being adopted around the world, he said.

Revamp projects can incorporate elements from existing acid-based alkylation units, such as feed treating, product separation and product treatment units for propane and butane. New units include the reactor, catalyst regeneration unit and a product separation unit for alkylate.

The ISOALKY has other advantages over acid-based process technology according to Honeywell. It is better at handling propylene and C5 olefins. It can even use ethylene as a feedstock.

Mike Hockey
Director of External Communication, PMT