Corn Oil Extraction: it's all in the data
This article featured in the July/August 2019 edition of the Biofuels International Magazine. biofuels-news.com/
The story behind Trucent’s updated program started with a basic question, says Jennifer Aurandt-Pilgrim, director of technical services. “Our clients were asking us, ‘Why does our corn oil performance change from day to day, or when we change an enzyme, what’s going on?’” When she looked for papers and published data to find some answers, she couldn’t find any. “So we set out to make our own database for corn oil extraction.”
The Trucent team started collecting samples from its 30 dry grind ethanol plants and quickly uncovered another issue. “We found the analytical tools being used were not very good,” she explains. They weren’t getting the total oil number from the different matrices at corn ethanol plants: whole stillage, thin stillage, wet cake, syrup. “So we developed our own analytical techniques.”
A statistical analysis of the data collected over five years identified several key performance indicators that affect corn oil extraction, such as thin stillage hold time and the temperature at the centrifuge. Using those insights, Trucent began working closely with 18 plants to optimize corn oil extraction, working with the entire plant to enhance operating parameters and chemistry.
That led to the next project: to evaluate available emulsion-breaking chemistry. “All of our plants asked, ‘can we optimize the emulsion breaking chemistry’? So, our lab developed a method where we can screen different chemistries at lab scale, instead of having to do it at the plant scale where you have to meet feed regulations.”
When the new screening method was ready, Trucent worked with Croda’s patented chemistries, which outperformed polysorbate-based emulsion breakers. “The sample from Croda worked really well,” Aurandt-Pilgrim says. “We knew certain characteristics of the stillage are inhibiting and activating the chemistries function.
We worked with Croda to optimize the emulsion breaker in response to these results. In the end we designed an emulsion breaker specifically for dry-grind ethanol plants, tweaking the chemistry-based upon feedback from our screening method.”
As a brand new, patented non-polysorbate based chemistry, GRAS (generally regarded as safe) evaluation followed. Croda holds the patent and Trucent has exclusive marketing rights. This summer, Trucent began rolling out the distillers corn oil (DCO) emulsion breaker, trademarking it Ascent. Not only is it the first emulsion breaker specifically designed for DCO extraction, Aurandt-Pilgrim points out, it is also made at Croda’s Delaware facility that uses corn ethanol, and not petroleum, for the creation of the reactant chemistry.
Initial plant trials indicate Ascent delivers a significant reduction in chemistry dosage – on average 50%. Plant trials showed an improvement in DCO yields, with one plant, one that wasn’t getting good results from polysorbate chemistry, seeing a strong one-gallon-per-minute yield gain.
With such promising trials, Aurandt-Pilgrim is excited to see the first corn oil totes go out to clients this summer. “We’re going to roll it out slowly to make sure it’s working well, and to be able to optimize if needed,” she says. “Also, the chemistry is brand new and we have to do a deliberate scale-up of the product.”
In addition to the new chemistry, Trucent’s data project fostered other technology improvements. Based on what was learned about factors inhibiting and helping extraction, the company introduced the COSS SL, its optimized high-speed disc stack centrifuge. “We changed a few parameters, disc spacing, the way we wash it and pretreatment components of the machine to optimize,” Aurandt-Pilgrim says.
One data finding resulted in a new technology for DCO syrup conditioning, the TruShield-SC. “We found a strong correlation with particles over 600 microns and lower oil production and higher viscosity,” she says. The new mechanical screen removes larger particles from the syrup, increasing DCO yield by 6% or better, decreasing viscosity, and decreasing emulsion-breaking chemistry usage.
With the new chemistry, enhanced mechanical systems, and its three-year-old service program, Trucent has achieved its goal of a holistic offering to the ethanol industry. “Our clients were asking for one phone call for help with corn oil extraction,” Aurandt-Pilgrim says. “Instead of calling the centrifuge guy and the chemistry guy, they can call us. We can optimize their centrifuge and their chemistry, based on what we see. Using our proprietary analytical techniques, we can tell them how to extract more oil by telling them where they are losing oil, and look for efficiencies at the whole stillage decanter and the corn oil centrifuge.”
“The big push in the industry is to capture as much oil as possible,” Aurandt-Pilgrim says. “It’s an easy way to make more money.” The current average value of dried distillers grains with solubles (DDGS), generally reported in dollars per ton, amounts to $0.065 (€0.058) per pound, compared to DCO valued at $0.27 (€0.24) per pound. The difference in value more than makes up for the reduction in DDGS poundage when removing the oil.
“I think in the past four months, the number of phone calls I receive has tripled,” she reports. “Plants are realizing they are leaving money on the table when they leave that corn oil in the DDGS. They want to get as much oil as possible, saying our feed tag is no limit. We still have the international feed tag that plants want to respect, but most plants now are realizing that they can take a discount on DDGS, extract more oil and still get increased revenue.”