Nighttime photo of Geismar biorefinery facility in Geismar, Louisiana against black sky


REG utilizes Bio-Synfining® technology developed and patented by our Synthetic Fuels Division in Tulsa, Oklahoma. The Synthetic Fuels Division was launched in 2014 as part of an acquisition that included the 75 million gallon per year nameplate capacity biorefinery located in Geismar, Louisiana. The Geismar biorefinery produces a high cetane renewable diesel fuel that can be blended with petroleum diesel in all proportions and can be produced to meet arctic cloud point requirements. The process allows our Geismar plant to utilize a wide array of feedstocks including inedible corn oil, used cooking oil, waste vegetable oils, animal fats, greases and vegetable oils to produce a renewable diesel fuel that meets the same requirements as ASTM D975 specification for petroleum diesel.


The Bio-Synfining process, protected by 38 active and pending patents, utilizes a wide variety of feedstocks that are turned into high quality renewable fuels.

The first step in this process is pretreatment — which removes contaminants to create a pure feedstock for the reactor section.

Feedstock is physically and chemically treated to remove physical contaminants 

The pretreated feedstock is charged to a high-pressure reactor system where the renewable molecules are transformed into clean-burning saturated hydrocarbons. High-pressure hydrogen and a patented catalyst configuration are used to affect the chemical transformation by saturating unstable double bonds (hydrogenation), reacting with oxygenates of the fatty acid molecules to form hydrocarbons and water (hydrodeoxygenation), and ​removing sulfur molecules (hydrodesulfurization) ​from the intermediate renewable hydrocarbons.

The intermediate hydrocarbons are very pure paraffins — they are then isomerized to reconfigure the molecules into branched paraffins (isoparaffins) to yield low cloud point clean fuels that are characteristic of the process.

The final step ​in this process is classic refining — the products are distilled into three main products: renewable hydrocarbon diesel, renewable naphtha and renewable liquefied petroleum gas.

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