Gustav Quint at AFRY works as a process engineer, using new technology that makes a difference for the future.

That’s according to Gustav Quint, a process engineer here at AFRY. In the spring of 2024, St1 inaugurated its new biorefinery in Gothenburg – a project Gustav was involved in from start to finish. But what does it really mean to build a new facility while incorporating new technology for a greener society?

Can you describe your role?

As a process engineer, I usually get involved in the early stages of a project, which gives me a great opportunity to influence the final design. The process engineer needs to understand the function of the plant—what needs to be produced, separated, or stored—and determine the necessary temperatures and pressures and how they should be controlled. We calculate process parameters for the equipment, such as the pressure increase in a pump or the heat transfer area required in a heat exchanger. Then, other specialists make it a reality, like piping and automation engineers who create models for all the pipes and control systems for the control valves and transmitters. In the end, it’s a close collaboration with the operations team at the finished plant.

Greener raw materials in the oil industry – what does that mean?

In practical terms, there are differences in handling vegetable oils compared to fossil oil. For example, green raw materials need to be kept warm to prevent solidifying, and they are often more corrosive, requiring more expensive materials for pipes and equipment. A major challenge is to design the entire value chain to source good and affordable green raw materials.

When we talk about vegetable oils, what types of raw materials can be used and what happens in the process?

Most fats found in nature can be used to make fuels, but it’s most suitable to use those that don't compete with food production. For instance, used cooking oils (like frying oil) or slaughterhouse waste work very well, as does tall oil, which is a byproduct of paper pulp manufacturing. These often need to be pretreated in a pretreatment plant to ensure impurities that could otherwise damage the main process are removed from the oil. This means you need to design a process to remove metals, chlorides, and similar substances to get a cleaner and finer oil to feed into the main process units. In the subsequent steps, the pretreated vegetable oil is converted into branched hydrocarbons.

Why are branched hydrocarbons important?

Fats consist mostly of triglycerides and fatty acids, which are poor fuels because they are corrosive and can easily clog engines. When treated with hydrogen, the three long chains of the triglycerides break apart, and the acidic ends of the fatty acid molecules are converted primarily into water. What remains are long, straight, non-corrosive hydrocarbons that burn well but unfortunately still solidify easily. Therefore, the oil needs further treatment in what's called an isomerization reactor. Here, the straight hydrocarbons are shortened and branched to produce diesel and jet fuel with good cold properties, similar to the common fossil versions. In the end, the oil consists of a mixture of different carbon chains that need to be separated into their respective product types: gasoline, jet fuel, and diesel. Once we've done that, we have a finished fuel!

How is residual waste handled in the process?

Several byproducts are formed when the vegetable oil processes. About 10% becomes water, and light hydrocarbons and dirty gases containing carbon dioxide, carbon monoxide, and hydrogen sulfide are also produced. The light hydrocarbons can be used as fuel in the process or as a product in the form of LPG. The water and dirty gases, however, need to be treated in different plants before they are clean enough to be released.

Why is this transition happening now?

The basic technology of hydrogen treatment has been around for a while, but high raw material and production costs compared to fossil fuels have slowed the development. Now, the market is shifting more toward green solutions, and there are legal requirements for more renewable fuel, which is causing the market to grow. As it has grown, the technology has developed, been refined, and adapted to the new raw materials (e.g. vegetable oil).

Do you see other areas for development for more renewable fuel?

Absolutely. There are raw materials beyond vegetable oil to utilize – for example, forest residues and byproducts, where pyrolysis oil from sawdust can be used in biofuel production. There is great potential in taking residual streams from paper and timber production to a biorefinery, but to my knowledge, it's not yet done on a large scale. This is apart from tall oil, which has already been used for diesel production for more than a decade.

Can you briefly describe the project for St1 and their new production plant?

The project for St1's new plant consists of an investment in several smaller plants and a main plant for the production of fossil-free fuels like HVO (hydrogenated vegetable oils), a renewable transport fuel that can be blended with or replace diesel. These fuels have significantly lower carbon footprint than fossil fuels. In St1's new plant, called the GPU (Green Production Unit), the pretreated vegetable oil is taken in and refined before it can be extracted as fossil-free diesel and jet fuel. At the same time, some other components for gasoline and LPG can also be extracted.

Why is a project like St1's new biorefinery so important for the transition to a more sustainable society?

It's quite simple – we need to reduce our carbon dioxide emissions, and biofuels are a step toward success. It's an important piece of a larger puzzle that can contribute to reducing emissions in parts of the transport sector, such as air travel, which are difficult to fully electrify.

How do you view the development within the industry?

In the five years I've been working, I feel the development has been strong. The entire process industry is being pushed forward by the green wave because there is so much to do in our industry to transition to a more sustainable sector. My team has worked on many projects in renewable fuels, but also in other sectors of the chemical industry where there are renewable aspects.

One example is jet fuel, where there is great development potential because the EU will start regulating the amount of renewable fuel that must be blended into jet fuel within the next ten years. This will expand the green market even more and create many new opportunities in the fuel industry.

In Sweden, we have much of what's needed in terms of renewable energy—the forest with its biomass, and more. I think if society wants to, society can solve it. We have better conditions in Sweden than in many other places. I’m optimistic about the future.