The Diamond Green Diesel plant is located at Valero’s St. Charles refinery site, Norco, Louisiana, US. Image courtesy of Ken Lund.
The Diamond Green Diesel plant is being expanded to produce 675 million gallons of renewable diesel a year.
Darling Ingredients procures and supplies used cooking oil and inedible corn oil as feedstock for the Diamond Green Diesel plant.

The Diamond Green Diesel plant located near Valero Energy’s St. Charles refinery, Norco, Louisiana, US is being expanded to more than double its renewable diesel output.

At 18,000 barrels per day (bpd) capacity, the Diamond Green Diesel plant is currently the biggest renewable diesel production facility in North America.

The £848m ($1.1bn) expansion project is intended to increase the daily output of the plant to 44,000bpd by the end of 2021.

The Diamond Green Diesel facility in Louisiana has been producing renewable diesel from recycled animal fats, used cooking oil and inedible corn oil since 2013.

The renewable diesel plant is owned and operated by Diamond Green Diesel (DGD), a 50:50 joint venture between Valero and Darling Ingredients.

Location and site details

The Diamond Green Diesel plant is located at Valero Energy’s 340,000bpd St Charles oil refinery site that occupies 1,000 acres along the Mississippi River at Norco, Louisiana.

The expansion facility is being developed on a 28-acre site adjacent to the existing renewable diesel plant.

Diamond Green Diesel plant expansion details

The current expansion project was approved by the Diamond Green Diesel joint venture partners in November 2018.

The annual renewable diesel production capacity of the plant was increased from 160 million gallons to 275 million gallons in an earlier expansion which was completed in August 2018.

The current expansion will increase the annual output of the facility by 400 million gallons to 675 million gallons.

The expansion project will also add 60 million gallons per year of renewable naphtha production capacity at the plant.

Processing technology for the Diamond Green Diesel plant

The Diamond Green Diesel plant employs EcofiningTM technology for processing the biomass-based feedstock to produce renewable diesel at its facility.

The EcofiningTM processing technology is jointly developed by Honeywell UOP, a subsidiary of Honeywell International, and Italian oil and gas giant Eni. The Diamond Green Diesel plant is the first plant to use this technology.

In the Ecofining process, the biomass-based feedstock first undergoes hydrogenation to produce paraffins which further pass through an isomerisation reactor to produce renewable diesel.

The renewable diesel produced at the facility is claimed to reduce greenhouse gas emissions by up to 85% when compared with conventional diesel.

Transportation and storage facilities

Diamond Green Diesel (DGD) signed a lease agreement with International-Matex Tank Terminals (IMTT) to use its St Rose terminal in Louisiana in February 2020.

As part of the agreement, IMTT will construct two 8km-long pipelines from the Diamond Green Diesel plant in Norco to the St.Rose terminal and provide 790,000 barrels of storage facilities for biomass feedstock as well as renewable diesel product from the facility.

IMTT is a wholly-owned subsidiary of Macquarie Infrastructure Corporation. The pipelines and the storage facilities are scheduled to be in operation when the Diamond Green Diesel expansion is commissioned in late 2021.

Diamond Green Diesel partnership details

Valero is one of the biggest independent refiners in the world. It operates a total of 15 petroleum refineries and 14 ethanol plants across the US, Canada, and the UK.

Valero has an aggregate refinery throughput capacity of approximately 3.2 million barrels per day (mbpd) while its total ethanol production capacity is estimated to be 1.73 billion gallons a year.

Darling Ingredients specialises in the production of natural ingredients from edible and inedible bio-nutrients. With processing operations in more than 200 locations globally, it supplies natural bio-nutrient residuals for different industries including pharmaceutical, food, pet food, fuel, bioenergy, and fertiliser.

The company also collects used cooking oil and residual bakery products. It operates in three industry segments namely feed ingredients, food ingredients, and fuel ingredients.

The Diamond Green Diesel joint venture leverages Darling Ingredients expertise in feedstock procurement and supply.

Diamond Green Diesel also plans to build another renewable diesel plant at Valero’s Port Arthur refinery in Texas. It started the process of advanced engineering and development cost review in September 2019.

The proposed plant is expected to have an annual production capacity of 400 million gallons of renewable diesel and 40 million gallons of renewable naphtha.

The final investment decision (FID) on the Port Arthur green diesel facility is expected in 2021.

Renewable diesel vs biodiesel

Renewable diesel is distinct from biodiesel in terms of chemical properties as well as the processes applied for its production.

Renewable diesel is similar to petroleum-based diesel in chemical properties. It is produced by catalytic hydrogenation and isomerisation processes. Renewable diesel, also known as hydrogenated vegetable oil, is a drop-in alternative fuel that can replace conventional diesel as a transportation fuel.

The traditional biodiesel comprises fatty acid methyl esters (FAME) that are produced through transesterification of vegetable oils and fats. It can be used as transportation fuel when blended with conventional diesel.

Neste, an oil company based in Finland, is the world’s biggest producer of renewable diesel. The other prominent producers of renewable diesel include Eni and Sweden-based Preem.