Whether the end product is biodiesel, renewable diesel (RD), or sustainable aviation fuel (SAF), feedstock pretreatment is a critical to the economic, efficient and reliable operation of a biofuel plant. As compared to traditionally used, higher-quality biodiesel feedstocks, the momentous RD and SAF markets are largely targeting waste feedstocks, the impurities in which require more complex pretreatment processes to meet quality requirements. While Austria-based BDI-BioEnergy International GmbH is well known for its Repeatable Catalyst, or RepCAT technology, the company’s BDI Advanced PreTreatment process is another result of 25 years of experience and thorough understanding of the processing of oils and fats, allowing producers the ability to test and process a wide range of feedstocks—with support every step of the way.

Feedstock Flexibility
In a high-level explanation, BDI’s flexible and modular pretreatment system utilizes a Tricanter process, followed by drying and advanced adsorption, especially designed for waste feedstock. The latter step is critical to an efficient process, says Manfred Baumgartner, BDI director of biofuels technology, and BDI will assist customers in selecting the most suitable adsorption medium, currently of which there are a range of different types on the market.

As BDI’s pretreatment system is suitable for the processing of fresh vegetable oils, waste oils and fats, it provides an advantage that will well-equip producers in the evolving and increasingly competitive feedstock landscape, according to Baumgartner. “The biofuel industry is seeing a change in feedstock coprocessing—a trend from vegetable oil to waste oils is happening right now,” he says. Mainly high-quality feedstocks have been used in the past, and though they are still being used for coprocessing, waste oils are becoming highly sought after. With the global market and resulting feedstock demand quickly growing, Baumgartner believes that feedstocks will become much scarcer in the future. Therefore, the ability to process a variety of waste oils and low-quality raw materials will become an even more important benefit to biofuel producers—and BDI-built plants already have the capability to do so. “These plants are specially designed for waste oils,” Baumgartner says. “A flexible pretreatment process configuration is essential to address all impurities, and in particular, this applies when different types of feedstock are processed in the same production line. We build them flexibly, so that all precautions have been taken for these challenges down the road.”

One of those challenges, for example, may be processing rendered animal fats with high polyethylene (PE) particle concentrations, which cannot be removed through traditional pretreatment methods. “This easily results in capacity problems,” Baumgartner says. He tells Biodiesel Magazine that BDI has developed a patent-pending, smart PE removal process that is installed upstream of the prepurification unit, and operates without filtration. In cases where feedstocks without PE particles are processed, the unit can be bypassed, according to Baumgartner. If required, other units can be added downstream, for example—to reduce or convert free fatty acids.

As for a recent example of a pretreatment plant BDI has delivered, repeat customer Crimson Renewable Energy L.P., in Bakersfield, California, underwent commissioning in 2020. The 40,000-ton plant pretreats waste oils and fats for processing into biodiesel.

R&D, Customer Support
Baumgartner emphasizes BDI’s ability to react quickly to assist customers in testing new feedstocks. The company prides itself on its customer service, providing reliable support during the lifetime of the plant, from feedstock evaluation in the lab, to startup of the plant to post-commissioning, working with them to optimize production, whether it’s a pretreatment or biodiesel plant. And support is available 24/7 via a hotline.

Research and development, a cornerstone of the company’s business model,  has paved the way for the technological developments BDI has achieved to date—and there is much more in store, according to Baumgartner. “We have conducted intensive research with a special focus on further reducing phosphorous and metals in poor-quality oils and lowering residual concentrations, as well as reduction of organic chlorine compounds,” he adds.  “We have achieved positive results and are at a breakthrough point. This solution will be a significant advantage for BDI customers in the near future, and it will soon be ready for the market.”