Fabricating a Future for Biodiesel

by Ron Kotrba (Biobased Diesel Daily) With prices for cleaner feedstocks through the roof, Tactical Fabrication and Smisson-Mathis Energy have forged an all-inclusive, turnkey model for biodiesel production based on the least desirable and lowest-cost materials. After years of development, they are now ready to roll it out to the world.

One might consider Frankie Mathis, owner of Tactical Fabrication LLC, a soothsayer of sorts. Sure, he is a successful business owner with decades of metal-fabrication experience. More recently, in the past 10 years, Mathis has delved head first into designing, engineering and building biodiesel plants and the processes that make them work. But years ago, he saw what few others could foresee and began developing a business model around that vision. Now, he and his crews at Tactical Fabrication and Smisson-Mathis Energy are ready for the world to take notice.

In 2015, when Mathis began the early feedstock-investigation work that would eventually culminate in SME Dublin LLC—a 5-million-gallon-per-year (mgy) biodiesel facility in Dublin, Georgia, owned by Smisson-Mathis Energy, a joint venture between Tactical Fabrication and The Smisson Group of Macon, Georgia—he did so with two of the dirtiest, least desirable, most problematic and lowest-cost materials in mind: brown grease from restaurant grease traps; and FOG, or fats, oils and greases from sewage and wastewater-treatment plants. Used cooking oil prices might have been high then, but no one could have foreseen the rapid growth in renewable diesel and sustainable aviation fuel (SAF) projects coming years later, and the extreme demand on “cleaner” feedstocks and the upward pricing pressure that comes along with it. Now, with cash bids for soybean oil surpassing 90 cents a pound, inedible tallow at 80 cents and choice white grease at 75 cents—making the feedstock costs alone for a gallon of biobased diesel from these three materials range from $5.60 to nearly $7 a gallon—this groundwork Mathis laid years ago to produce on-spec fuel from materials some outfits still have to pay to get rid of was nothing short of brilliant.

Mathis and his teams at Tactical Fabrication and Smisson-Mathis Energy have developed an alpha-omega strategic model to roll out to industry that encompasses feedstock origination, collection, cleanup, plant staffing, processing, and selling. This is the definition of a turnkey operation.

He says those from whom SME Dublin gets its brown grease do not collect grease to sell. Rather, they collect it for land applications or landfills. “Those are the collectors we are working with, which gets us very near zero cost for the feedstock. For instance, in Dublin, every drop collected was land-applied in Georgia.”

It began with a pilot project that involved developing the best way to harvest the grease directly from the wastewater-treatment plants. Enter its FOG Harvester.

Using commercially available equipment, the FOG Harvester separates the water, solids and oils on site so the water can remain at the treatment plant, the solids can be used for anaerobic digestion, and the oils are suitable for biodiesel production.

“We have a great relationship with Novozymes, it’s not exclusive but we are a preferred engineering partner,” Munk (Bo Munk, a technical consultant for Tactical Fabrication and SME Dublin) says. “We know how to make their enzymes work with brown grease. It’s extremely important for us to use our experience to tweak the reactor function with brown grease. It’s not rocket science, but once you get it, you have to be able to do it again and again. The enzymes are robust, but you need to understand the enzymatic process. There are good and bad sides. It’s very different than traditional biodiesel processing. Brown grease is very high in free fatty acids (FFA), which is different than working with glycerides.”

With very little glycerin bound up in glycerides, the end result yields very little free glycerin. “Maybe a half a percent, but we’re not looking to harvest that,” Munk says.

The enzymes convert 95 percent of the FFA into methyl esters, so SME Dublin uses Purolite resins to react the remaining 5 percent FFA into biodiesel on the back end of the process. “We do that rather than caustic washing it out and creating a loss,” Mathis says. READ MORE