Innovations in Biodiesel Technology

New biodiesel process technologies continue to emerge, promising optimization of production through greater efficiencies and lower costs.
By Ron Kotrba | January 06, 2020

Crown Iron Works
As a trusted advisor to the world’s leading multinational oilseed, animal feed and alternative energy processing companies serving more than 3,000 customers per year for systems, equipment and aftermarket support, few companies have the depth of experience in oilseed and biodiesel process design, customized engineering and construction as Crown Iron Works. The global Minnesota-based firm has built 50 biodiesel plants around the world. Like any good engineering company, Crown continues to refine its biodiesel process technology, evidenced by the advent of its recent process upgrade: Advanced Catalyst Reduction and Economization.

“This innovation came from two fronts,” says Kris Knudson, Crown’s vice president of global sales and marketing. “With Crown being primarily an engineering company, one core value is continuous improvement. That’s part of an engineer’s DNA—optimizing ways to run plants, achieving lowest operating costs and highest efficiencies. Secondly, we work with our customers to identify and meet their needs.”

Biodiesel markets are competitive, and operating costs are “a big deal,” Knudson says, adding that one of the biggest costs for consumables in biodiesel production is catalyst. “That is what ACRE targets directly,” he says.

The ACRE upgrade employs a third transesterification reactor to provide greater residence time and achieve stoichiometric reaction. “We’re maximizing the catalyst and reusing it to its full potential,” Knudson says. “We do this through a blending system and extra residence time to get the most use of the catalyst without waste.” The design also reduces acid usage because with less alkaline chemistry comes less acid for neutralization.

In addition to catalyst reduction, ACRE is energy-efficient, lowering steam and energy costs for biodiesel producers. Economizers and heat exchangers are utilized to take advantage of excess process heat, reducing the amount of new steam introduced. Likewise, the same is true for cooling. “We maximize process streams to interchange, economize and cool without having to use as much cooling-tower water, which is an expensive utility,” Knudson says.

Crown’s biodiesel design uses decanters instead of centrifuges for phase separation. “Our philosophy is to make a user-friendly, robust design,” Knudson says. “Mechanical separation requires greater electricity use and there is inherent downtime for maintenance. Decanters use residence time and gravity to create separation. It’s very simple and robust, not much can go wrong. It can handle small disruptions in incoming feedstock. And decanters don’t require energy. Mechanical separators have high energy costs—they use big motors that require electricity and have more moving parts, which means more scheduled and emergency downtime. Also, changes in feedstock are instantaneously pronounced in centrifuges. We’re impartial on this, as we are not a separator or centrifuge supplier. We can provide a centrifuge-based design if asked. We analyze all the options, but we believe gravity decanters are typically the best system for our customers.”

The ACRE upgrade can be installed in Crown-designed, decanter-based processes or competitor-designed biodiesel plants with centrifuges. “We can do either,” Knudson says. “Our aftermarket team can assess competitor plants and model ACRE integration in non-Crown designs.” Crown has also made a strong commitment to its Aftermarket Parts and Field Services. “This is one of the biggest growth areas for our business,” Knudson says. “We’re really proud of our talented team. Customers may not have the specific subject-matter expertise, but they can call us and we’ll deploy our field services team to troubleshoot, assess and offer solutions.”

Between catalyst reduction and economization, biodiesel producers installing ACRE can expect to achieve multiple cents per gallon in savings, depending on region, plant design and consumable costs. “The primary savings is catalyst reduction,” Knudson says. “It can vary. Not all plants are the same. Some may have more opportunities to economize while others may have already gone through those efforts.” He adds that a 30 MMgy plant can expect to achieve a 40 percent reduction in catalyst use, resulting in approximately $2,000 a day in savings.

Four commercial installations of ACRE have been installed in multiple geographies running multiple feedstocks, and Crown is currently selling this innovation in its new designs. Its fifth ACRE system is being installed in a greenfield build in Brazil—Crown’s largest biodiesel plant to date at 1,100 tons a day (roughly 120 MMgy). Knudson says ACRE typically provides biodiesel producers a two-year ROI.

In September, Crown opened its new, 68,000 square-foot, $12 million Global Headquarters and Innovation Center in Blaine, Minnesota. The new facility includes both classroom-style and hands-on training rooms and a 15,000 square-foot pilot plant. “Crown has a strong focus on training,” Knudson says. “At our new Innovation Center, we can provide university-style classroom training. We can comfortably bring in 50 customers, and we have all the AV and IT set-up for presentations, break out discussions and group work. Then we can move from the classroom to our hands-on training center.” The center includes cutaways and skids of key equipment so customers can understand how the machinery works and the components involved.

The pilot plant includes smaller versions of the equipment Crown sells, control rooms mirroring those in production facilities, and a lab next door. “We are definitely excited to partner with our customers on training,” Knudson says. “With this pilot capability, we can bring in our customers’ specific feedstocks and provide them great confidence in what they can expect on the backend. For example, soybeans from Minnesota are different than those from Brazil, and those nuances mean a lot to our customers.”

While ACRE is one of Crown’s latest innovations, it isn’t the company’s only one. It will soon unveil a new pretreatment system for renewable diesel. “We are tapping into our toolbox to repurpose and reuse our decades of knowledge and experience around edible oil refining and biodiesel processing to create a robust pretreatment system for renewable diesel,” Knudson says. “The focus is contaminant removal to reliably extend catalyst life of the hydrotreater unit.”

Knudson says ACRE is the result of Crown’s commitment to its customers’ success. “With our mindset of continuous improvement and our connection to market needs, we are there for our customers,” he says.

Plasma Blue
Plasma is a complex state in which free electrons and positive ions coexist in matter when sufficient energy is introduced. Science often refers to plasma as the fourth state of matter, but Tom Slunecka, CEO of the Minnesota Soybean Research & Promotion Council, refers to it as the next big wave in biodiesel process technology.

“This is a piece of disruptive technology that will forever change the way biodiesel is viewed,” Slunecka says, referring to a liquid phase plasma discharge technology MSR&PC is backing. MSR&PC was introduced to the breakthrough four years ago, shortly after the organization implemented a review process for new technologies that could benefit Minnesota soybean farmers. “We implemented a stage-gate process to make sure our investments are not being misused,” Slunecka says. “The goal is to fail early and cheaply. We push the technology hard early on to make sure we’re on solid ground. If it survives, we continue to fund it.”

The plasma technology focuses entirely on the main processing step in biodiesel production—transesterification—and operates well, according to Slenecka, with the same quality feedstock suitable for standard base conversion, regardless of its origin. Integration of a 5’x7’ skid-mounted, low-capex unit into an existing biodiesel facility would provide an additional 1.5 MMgy of production capacity with little to no changes to pretreatment or posttreatment systems.

Using low-amperage, high-frequency electricity, the continuous flow technology momentarily turns the liquid mixture into plasma. “Typically matter goes from liquid to gas to plasma,” Slunecka says, “but unless it’s happening so fast we can’t detect it, we’re going directly from liquid to a plasma state.” The phase change happens in milliseconds. “What makes this so unique is it’s continuous flow,” he says. “In scientific literature we see this done from a pulse standpoint, but not continuous flow.”

A familiar mixture of oil, alcohol and catalyst is run through the plasma unit, but with several key differences. The reactor creates an excited molecular state for the mixture, which results in improved conductivity between the elements. “This excited state allows us to use a lower-cost catalyst that translates into reduced costs per gallon,” Slunecka says. He wouldn’t reveal what the lower-cost catalyst is but says it’s a byproduct of a large industrial process and is widely available globally.

“Supply constraint is not an issue,” he says. “It’s all part of the magic sauce. Furthermore, depending on the cost of natural gas vs. electricity in a given region, energy costs are lowered too. The same is true for the carbon-intensity (CI) score.” In markets like California, up to four cents a gallon can be monetized through a lower CI rating.

Several other key benefits are inherent in the technology. It requires less process heat since the reactor can perform conversion at any temperature, according to Slunecka. The small physical footprint and modular design mean biodiesel producers can scale production up incrementally, without requiring vast floor space for process tanks. “We think these units will help plants through bottlenecking issues in transesterification,” Slunecka says. “All they need is T-lines before and after the reactors, and most of those already exist. Then they can add new capacity without any major changes to the plant, other than some electrical requirements to bring power to where the reactors are placed. That’s it—T-lines, electric power and some software changes to the PLC.” Slunecka says PLC work has recently begun and, once completed, will be fully integrable into existing systems at plants. “It’ll be software that plants recognize,” he says. There’ll be a PLC on the plasma unit, but that will be more for redundancy.” Capex is also low compared to other technologies a plant might consider, Slunecka says. “Based on operating gallons and 5 to 8 cents lower production costs, the equipment has a 15- to 18-month payoff,” he says.

Perhaps one of MSR&PC’s most celebrated characteristics of the liquid phase plasma discharge technology is its easy integration into ethanol plants and ability to use ethanol for transesterification of distillers corn oil. “That can be a gamechanger for ethanol producer customers that want to add biodiesel processing,” Slunecka says. “When ethanol is used, the glycerin no longer carries methanol and thus can be used as a feed additive to their distillers grains. Also, ethanol is more difficult than methanol in biodiesel production, and water is a major part of that, but this system can handle more water than most transesterification processes. That’s one advantage. Another is scale. Typically, ethanol plants don’t want to deal with biodiesel on such a large scale, which is often needed to be cost-effective. By dramatically reducing capex, we think our plasma biodiesel reactors are a viable option for ethanol producers.”

MSR&PC launched a company, Plasma Technology Holdings LLC, which has exclusive license to the liquid phase plasma discharge patents from the University of Minnesota, whose researchers originally developed the underlying technology. Applications for U.S. and international patents are in place. Plasma Blue LLC has also been organized for commercializing the technology in the bioenergy field.

Using a slipstream of soybean oil from its small, specialty crush facility, MSR&PC will install a liquid phase plasma discharge processing unit at its new Soy Innovation Campus in Crookston, Minnesota, which is expected to break ground in July.

A great milestone in biodiesel history was achieved 10 years ago. In 2010, Biodiesel Amsterdam BV came online with its large-scale multifeedstock plant that was designed, engineered and built by BDI-BioEnergy International. This wasn’t BDI’s first multifeedstock plant that could process 100 percent waste oils and fats, but it was the Austrian biodiesel process technology provider’s largest at that time—100,000 tons per year (30 MMgy)—and would become the reference subsequent designs would follow.

Christine Riedl, technical sales manager for BDI, was responsible for engineering the facility. She arrived in Amsterdam in June 2010 to oversee mechanical construction of the project. Months later, during commissioning, the region was plagued with its coldest winter in five years, she says.

“The temperature was so low that the cooling tower was freezing up,” says Riedl, reminiscing about the challenges. “We called our headquarters and told them we needed more support on-site. We are so well-organized that, two days later, we had more BDI staff in Amsterdam supporting the commissioning.” It was a “cool” solution, she says—pun likely intended.

BDI’s multifeedstock technology is based on years of knowledge captured in voluminous databases of various feedstock properties, and reaction experience converting that same suite of feedstocks into quality biodiesel. The provenance of this reference plant erected in Amsterdam in 2010 links back to BDI’s first used cooking oil biodiesel plant, built in Austria in 1994 under Vogel & Noot—the company at which BDI founder Wilhelm Hammer worked and from which he bought the biodiesel-related patents needed to launch BDI in 1996. Other large-scale biodiesel plants built by BDI over the ensuing years were considered multifeedstock, including a 30 MMgy facility owned by Uniol AS in Fredrikstad, Norway, which opened in June 2009. But back then, in the early days of commercializing multifeedstock technology for the biodiesel industry, the term meant something different than it does today—in large part thanks to BDI’s work.

“The Norway plant is designed mainly for virgin oils, and only a minority of the feedstock can be waste oils or animal fats,” says Hermann Stockinger, vice president of global sales at BDI. “The Amsterdam plant can process 100 percent waste oils and fats.”

It’s no surprise that nearly 15 years after its founding, BDI went on to engineer and construct such a true multifeedstock plant using various concoctions of wastes. “From waste to value” has long been the company mantra. In those early days, Helmut Gossler, also a founder of BDI and former Vogel & Noot technician who helped groom Hammer on the technical side of the business; Michael Koncar, the founder of longtime BDI partner company VTU; and Martin Mittelbach of the University of Graz, considered by many to be the godfather of biodiesel; were brought in to foster this mission of building from the ground up an industry whose future would, unbeknownst to them at the time, come more and more to rely on this slogan—from waste to value.

“During their first management meeting in the mid-’90s, they already committed to sustainability, and to focus on waste-based feedstocks for biodiesel,” Riedl says. “It was a great milestone, such a commitment to the worst of the worst waste materials.”

The basic elements of BDI’s multifeedstock technology include physical and chemical feedstock pretreatment; acid esterification; a two-step, potassium-based alkaline transesterification; washing; distillation; and, of course, an optimized PCS—the brains of the system upon which all those decades of data are enacted.

Naturally, every plant is unique in one way or another, depending on the customer’s requirements, but they all—for the most part—share those basic tenants. “For example,” says Riedl, illustrating how each plant design can be unique despite having a base model to reference, “we’ve developed seven different esterification processes. Some customers want continuous vs. batch processing. Others don’t want to use sulfuric acid.” Each iteration is a technological accomplishment, with these advancements eventually culminating in RepCat.

“This has big advantages because it is a fully continuous process, and more importantly, it uses no settling processes,” Riedl says. “Due to this, we can produce biodiesel and glycerin in the same line.”

The intermingled biodiesel and glycerin are run through distillation and, afterwards, the distilled products separate much easier due to the binding interlayers between the products being stripped and left in the column bottoms. “After distillation, they separate with no problem,” Riedl says.

While times change and Biodiesel Amsterdam is now owned by U.K.-based Argent Energy, BDI continues to innovate. A patent is soon expected to be granted on a technique to either improve existing distillation systems or implement new units to drastically reduce sulfur from low-quality greases to 10 ppm.

Early on, during development of its multifeedstock technology, Riedl says some of the big companies using virgin oils for biodiesel laughed at the idea of using waste. “Afterwards,” she says, “as our design became established and we could show new customers our latest facilities and how they were working, selling the idea became much easier. But in the beginning, it was hard work. Such reference plants are our most important tool for selling.”

One important part of the company’s success, Riedl says, is a stable staff of committed employees. “The average length of employment for our staff is greater than 10 years,” Riedl says. “The longest is more than 20 years. Also, we are a big company, but we are still small enough to be flexible. The phrase, ‘That doesn’t work’—this does not exist in our vocabulary.”

Surface area is critical for fast, complete chemical reactions. When novel fiber reactor technology to drastically increase surface area is combined with that same approach to pretreat feedstock in a small, skid-mounted unit, the outcome is a remarkable new approach to biodiesel manufacturing. Add a midstream water-wash step and the result is Visionary Fiber Technologies Inc.’s Fiber Reactor Technology.

The idea was initially developed by a retired professor from Texas State University to investigate how the mass transfer characteristics of transesterification could be enhanced by greater surface area. The concept is to pack thousands of hair-width strands of stainless-steel fibers in a reactor to create thin ribbons of interstitial space within which reaction occurs. VFT, through its affiliates, now owns this patent portfolio and has global rights for commercializing this technology.

Andrew Horvath, VFT’s chief operating officer, says the first step is to flood the fiber reactor separator with water, alcohol and caustic. “A reservoir of this aqueous solution is on top of the reactor, so the tips of the fibers are always wetted,” he says. “From underneath we inject the organic phase.” Surface tension binds the aqueous solution to the fibers as oil pushes the fluid through the interstitial space, Horvath explains. “As the oil moves down, neutralization of the free fatty acids (FFA) occurs, turning them into soap,” he says. “The soap migrates to the bottom with the aqueous phase.” This step can reduce FFA content of distillers corn oil (DCO) from 15 percent to less than 0.5 percent. After FFA removal, the oil is sent to the second reactor for water-washing. The clean oil now flows into the third reactor for transesterification via VFT’s technology.

Horvath says VFT’s skids are perfect for ethanol producers seeking to co-locate biodiesel production on-site. One reason is the ability to use ethanol instead of methanol in transesterification. “When other technologies use ethanol, it creates more problems than solutions,” Horvath says. “The physics in our technology allows producers to leverage what ethanol can do for them.”

Ethanol plants have mole sieves, evaporation and distillation systems to break the azeotrope and recover water-free ethanol from product streams. Unlike others wishing to use ethanol for biodiesel manufacturing, ethanol producers can avoid tax implications with denaturant-free ethanol since it’s made on-site. Furthermore, the footprint is small: One skid is 5’x5’x10’. Three of these in a series are estimated to produce 5 MMgy or more of biodiesel from DCO, also produced on-site. In addition, the carotenoid-rich FFA stream stripped from the DCO feedstock can be added to the distillers grains for a nutrient-rich, higher-priced variety. Fuel performance of fatty acid ethyl esters (FAEE) is better than fatty acid methyl esters, Horvath says. “It has higher cetane, better cold flow and pourability characteristics,” he says. In addition, VFT’s biodiesel production skids have inherently low capex costs, ranging from 50 cents to $2 per gallon installed capacity depending on size and existing infrastructure, Horvath says, adding that the low-temperature, low-pressure process employs little energy—meaning lower variable production costs. Finally, he says FAEE produced via VFT’s skids have a low carbon-intensity score, which producers can parlay into cash in markets like California.

VFT has been working closely with industry players and has high hopes for deploying its technology in biodiesel production. “Its application in the biodiesel industry, specifically with ethanol plants becoming true biorefineries, is a beautiful thing,” Horvath says.

SI Group
As new biodiesel processes and feedstocks are commercialized, the resulting fuels must be coupled with the right additive chemistries for optimal performance. Enter SI Group. Acquired by SK Capital Partners and combined with Addivant in 2018, the new SI Group brings more than 100 years of excellence in manufacturing, intelligent expansion and global security of supply. Headquartered in Schenectady, New York, SI Group operates more than 30 manufacturing facilities on five continents with approximately $2 billion in annual sales and more than 3,000 employees.

SI Group’s Ethanox brand of antioxidant stabilizers have been in the market for 40 years. “We offer a wide array of chemical types and mixtures thereof to address the necessary performance,” says Kyle Elgert, senior marketing and new business development manager for SI Group’s fuels and lubricant additives division. “Biodiesel is unique. There’s no one catalyst, process or feedstock used, so fuel properties and performance attributes differ. We offer a variety of antioxidants under the Ethanox brand, from generic, broad-reaching products that work on a number of biodiesels and blends to more tailor-made options for treating a specific type of biodiesel.”

Oxidation impacts fuel stability, and this destabilization causes gum and deposit formation in fuel, harming storage and performance capabilities. “All fuel types are susceptible to oxidation,” Elgert says, “but biodiesel is particularly prone due to its chemical makeup. If left untreated, these deposits can impact how the fuel is meant to perform in an engine, often resulting in increased emissions and decreased fuel economy.” SI Group’s Ethanox antioxidants are designed to meet and exceed these challenges.

As biodiesel oxidizes, free-radical peroxides form. “These peroxides can lead to deposit formation disrupting engine operability or they can cause issues inside of storage tanks,” Elgert says.

“Antioxidants are designed to bind to the free radicals mitigating the effects early in the process before they cause widespread issues. It’s important to select an antioxidant capable of responding quickly and effectively before a situation arises. For a proactive approach, maintenance dosage of antioxidants ensures the fuel will be capable of performing as expected.”

SI Group works with its customers on a variety of fronts, from product testing to identifying performance outputs they seek to gain for the markets they are in—domestically or internationally. “We take the right chemistries in our portfolio and meet the tailored needs of our customers,” Elgert says. 

With its full suite of Ethanox-brand antioxidants, one might think SI Group could rest on its laurels—but this isn’t the case. “Our scientists are continuing to ensure our chemistry is the latest and greatest for an ever-changing fuel slate,” Elgert says. “SI Group remains enthusiastic in our mission to come out with next-generation antioxidants to do more and go further.” This enthusiasm, however, is not tied solely to antioxidants. “SI Group anticipates a full suite of performance chemicals to handle the opportunities that an evolving fuel slate and biofuels markets offer,” Elgert says.

 “We’ve been in the market for a number of years and we’re hungry to grow, and to understand the challenges this industry faces,” Elgert adds. “We look forward to working with individuals to combat those challenges.”

Biodiesel Production Technology Summit
A new conference dedicated to biodiesel and renewable diesel processing, the Biodiesel Production Technology Summit, will take place in Minneapolis June 15-17, 2020. Organized by BBI International and produced by Biodiesel Magazine, the event is a new forum designed for biodiesel and renewable diesel producers to learn about cutting-edge process technologies, new techniques and equipment to optimize existing production, and efficiencies to save money while increasing throughput and fuel quality.

The Biodiesel Production Technology Summit will feature premium content from technology providers, equipment vendors, consultants, engineers and producers to advance discussion while fostering an environment of collaboration and networking through captivating presentations and fruitful conversation, all with a single purpose—to further the biomass-based diesel sector beyond its current limitations.

From frontend pretreatment to backend quality measures and everything in between, this premiere event covers the technology gamut, leaving producers with practical solutions to their needs.
Presentations and discussions will focus on key areas of biodiesel and renewable diesel production, such as:

• Plant Upgrades

• Optimization (Debottlenecking & Efficiency Improvements)

• Retrofits

• Pretreatment (Esterification, Feedstock Cleaning, Dewaxing, Degumming, Fatty Acid Stripping, Filtration, Centrifuging, Etc.)

• Processing Equipment (Pumps, Valves,Tanks, Reactors, Filters, Boilers, Heat Exchangers, Centrifuges, Instrumentation, Etc.)

• Process Technologies—Biodiesel & Renewable Diesel

• Biodiesel & Renewable Diesel Catalysts (Acid, Base, Enzyme, Fixed-bed, Solid, Heterogeneous, Homogeneous, Regenerative, Recyclable, Metal, Hydrotreating, Etc.)

• Plant Automation & Process Control Systems

• Process Analysis

• Posttreatment (Fuel Washing, Polishing, Filtration, Centrifuging, Distillation, Methanol Recovery, Neutralization, Soap-splitting, CSFT, HVO Isomerization, Etc.)

• Adsorbents & Resins

• Fuel Quality Analysis

• Plant Services (Engineering, Consulting, Cleaning, Maintenance, Etc.)

• Glycerin Upscaling Technologies

• Biodiesel Upscaling to Alternative, Non-fuel Products

• Project Development—Biodiesel

• Project Development—Renewable Diesel

• Design/Build Innovations

• And more

For more than 15 years, Biodiesel Magazine has diligently covered the evolving biodiesel industry.

From the early days of soybean oil-centric conversions to the introduction of multifeedstock approaches, new quality controls, advanced process technologies, optimization techniques and the proliferation of renewable diesel production, Biodiesel Magazine was there. Now, the industry-leading trade publication is tapping into its extensive background in this market and the relationships it has developed to produce the Biodiesel Production Technology Summit, a valuable experience for stakeholders in the biomass-based diesel space.

“This has long been a dream of mine—to develop, organize and produce an event focused on biodiesel and renewable diesel process technologies and production,” says Ron Kotrba, editor of Biodiesel Magazine and program director for the Biodiesel Production Technology Summit. “So many different, fascinating techniques exist to produce biodiesel, along with a number of different approaches to produce more efficiently and cost-effectively. And with the relatively recent expansion of renewable diesel production domestically and internationally, it will be great to invite these producers, some of which are also biodiesel manufacturers, and technology providers into the discussion because our goal is all the same—to make biomass-based diesel mainstream so society can benefit from all it offers.”

Last January, Kotrba, who has been writing for Biodiesel Magazine since 2005 and editing the publication for more than 10 years, won the National Biodiesel Board’s “Eye on Biodiesel” Influence award.

John Nelson, vice president of marketing and sales for BBI International, says given the political uncertainty surrounding the Renewable Fuel Standard and biodiesel tax credit, timing could not be more appropriate for a new conference that focuses on low-cost biomass-based diesel production and efficiency. “In a business where pennies per gallon can mean the difference between success and failure, we think people want to hear about ways to make their fuel better and cheaper,” Nelson says.

Co-located with the International Fuel Ethanol Workshop & Expo, the Biodiesel Production Technology Summit conveniently harnesses the full potential of the integrated biofuels industries while providing focus on processing methods with tangible results for biomass-based diesel producers. The three-day slate of co-located events in Minneapolis will be the world’s largest gathering of biofuel producers.

Registration for the Biodiesel Production Technology Summit is free of charge for all employees of biodiesel and renewable diesel production facilities, from operators and maintenance personnel to board members, executives and owners.

Presentation ideas are being accepted now through Feb. 14. To submit an abstract, visit

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