The Alchemy of Biofuels: How an Additional Step Makes the Process Cheaper, Cleaner, and More Flexible

We all know it: The world urgently needs sustainable fuels to curb climate change. But the raw materials for these fuels are often a problem. Many of the available waste products such as used cooking oils, animal fats, or other residues are low-quality, heavily contaminated, and difficult to process. They are full of impurities that would cripple traditional production facilities.

So how can we efficiently transform these contaminated raw materials into high-quality fuels like renewable diesel and sustainable aviation fuel (SAF)? An innovative technology called Sulzer BioFlux™ pretreatment offers some surprising and, at first glance, seemingly contradictory solutions to this problem. Here are four facts that show how today's waste becomes tomorrow's fuel.

1.Fuel from the “Unusable”: The Art of Super-Cleaning

Many fats, oils, and greases (FOGs) are simply unusable for conventional fuel production. They are too heavily contaminated with impurities such as metals, phosphorus, and chlorides. Conventional methods fail to meet these requirements.

Here lies the first surprise: BioFlux™ technology utilizes a thermal pretreatment that can clean even the most challenging raw materials. An extreme example is Category 1 tallow, an animal fat considered particularly contaminated. The results are impressive. In tests, impurities were drastically reduced:

•       Metals: -99%

•       Phosphorus: -99%

•       Chlorides: -99.9%

Why is this so important? This is a true game-changer, as it unlocks a vast, previously untapped source of raw materials. Materials previously considered problematic waste are becoming a valuable resource for the energy transition, transforming a disposal problem into an opportunity for value creation.

2.Less is more: How a clever intermediate step makes the process cheaper

Normally, one would assume that every additional step in an industrial process increases costs and complexity. The BioFlux™ pretreatment proves the exact opposite. Although it is an additional process step, it makes the entire subsequent process significantly more efficient and cost-effective.

The reason lies in the chemistry: The pretreatment is not just cleaning, but thermal cracking. In this process, the complex fat molecules are broken down and chemically modified by heat. This step already does much of the heavy lifting, such as removing up to 50% of the oxygen from the molecules. The result is that the subsequent refining step (the so-called hydrotreating, a process in which hydrogen is used under high pressure to remove impurities and stabilize the molecules for fuel) has to do much less work. The decisive proof: Hydrogen consumption – one of the most expensive factors in biofuel production – is reduced by up to 50%. A comparison with conventional physical refining reveals the full extent of the benefits:

•       Lower investment costs: The investment costs for a BioFlux™ pretreatment plant are less than half those of conventional physical refining.

•       Lower operating costs: When pretreatment is integrated into the entire BioFlux™ system, operating costs and carbon intensity is reduced by 25%.

This defies conventional logic: An additional, intelligent step at the beginning makes the overall system leaner, cheaper, and more environmentally friendly.

3.Diesel or kerosene? Simply switch.

The fuel market is dynamic. Sometimes the demand for diesel is higher, sometimes for jet fuel. Producers must be flexible to be economically successful. The BioFlux™ platform is specifically designed for this purpose and can produce two main products: renewable diesel (also known as HVO) and sustainable aviation fuel (SAF).

Its key feature is its flexibility. By easily adjusting operating conditions and catalysts in the second process step (isomerization, where the molecular structure is rearranged to achieve either diesel or kerosene properties), the plant can flexibly switch between maximizing diesel and kerosene production.

This flexibility is a crucial economic advantage, enabling manufacturers to respond quickly and efficiently to the respective markets.

Discover how BioFlux™ can transform your renewable fuel operations contact Sulzer Chemtech today to learn more about this innovative technology.