HollyFrontier Corporation
Cheyenne, WY, U.S.

HollyFrontier Cheyenne Renewable Diesel Project

HollyFrontier (now HF Sinclair) chose Fluor to modify its Cheyenne Refinery to process refined, bleached and deodorized soybean oil for renewable diesel production. Fluor executed front end engineering and design (FEED), detailed engineering and procurement services on the project. A creative and collaborative execution approach helped safely achieve a six-month schedule reduction from the base case scenario, enabling the client to accelerate time to market.

Client's Challenge

HollyFrontier is an independent petroleum refiner and marketer that produces high-value light products such as gasoline, diesel fuel, jet fuel and other specialty products. Consistent with its commitment to being environmentally responsible and establishing sustainable practices, HollyFrontier had expanded its focus on producing renewable diesel and was repurposing its 86-year-old petroleum refinery in Cheyenne, Wyoming to produce approximately 90 million gallons per year of renewable diesel.

With the plant offline for the revamp, the team supporting the HollyFrontier project reached out to Fluor to help deliver a condensed engineering and project execution approach to safely minimize facility downtime. The plant produced its last barrel of crude in August 2020, and the conversion to renewable diesel production was completed in 2021.

Fluor's Solution

Fluor's scope included feasibility, FEED and detailed engineering for the inside battery limits (ISBL) facilities. Fluor acted as agent for the client in procuring all ISBL materials, services and equipment. Fluor also performed the pre-FEED studies for the hydrogen plant.

Two existing refinery units were revamped to produce R100 diesel, a distillate hydrotreater (DHT) and a naphtha hydrotreater (NHT). The combined units are referred to as the renewable diesel unit (RDU). The DHT converts the soybean oil to n-paraffins via olefin saturation and hydrodeoxygenation, while the NHT isomerizes the n-paraffins in a sweet catalyst environment to improve cold flow properties. Some equipment from other units was also integrated into the RDU.

The client and Fluor aligned early on the optimal balance in schedule reduction, quality requirements and capital investment. Developing high-quality deliverables that could be adapted for late changes was deemed the best approach to support safe and efficient construction while maintaining the accelerated schedule and supporting the client's economic model.


Fluor executed the FEED, detailed engineering and procurement services in an accelerated nine-month schedule, meeting the client's milestones to support the mechanical completion date. The Fluor team received several accolades from the client regarding its technical expertise, innovative thinking and strong collaboration. Fluor completed its scope on the project in 2021.