How is renewable diesel (HVO) made?

Renewable diesel can be produced through hydrotreating, gasification, pyrolysis, and other biochemical and thermochemical technologies. It is primarily produced through hydrotreating as described below.

Hydrotreating process

Feedstock collection

Renewable diesel is made from entirely renewable and sustainable feedstocks such as vegetable oils (e.g., soybean, canola, palm), animal fats, used cooking oils, and other waste oils.

Pre-treatment

The feedstocks undergo a pre-treatment process to remove impurities like water, metals, and particulates that could interfere with the hydrotreating process.

Hydrotreating

Hydrotreating takes place in a high-pressure and high-temperature environment usually within a refinery’s hydro-processing unit.

Hydrogenation: The feedstock is mixed with hydrogen and exposed to a catalyst, which facilitates the breaking down of triglycerides and fatty acids into simpler molecules.

Deoxygenation: Oxygen atoms are removed from the feedstock molecules in the form of water (H2O) or carbon dioxide (CO2).

Hydrocracking and Isomerization: Larger molecules are cracked into smaller, diesel-range hydrocarbons, and the molecular structure is adjusted (isomerized) to enhance the fuel properties.

Separation and purification

The product of the hydrotreating process contains hydrocarbons, water, and gases which are separated using distillation and other separation techniques.

The purified hydrocarbon product is then further refined to meet the required specifications for diesel fuel.

Blending and additives

The final product may be blended with additives to improve performance characteristics, such as cetane number, lubricity, and cold flow properties.

Quality control

The produced HVO undergoes rigorous quality control testing to ensure it meets all the necessary standards and specifications for diesel fuel.

The hydrotreating process allows renewable diesel (HVO) to be chemically identical to conventional diesel, providing a cleaner-burning fuel that can be used in existing diesel engines without modification.