By Jon Scharingson, Renewable Energy Group, Inc.
At first blush, distillation may not be a topic that piques your interest, or maybe you think you already know enough about it from petroleum refining.
Regardless, you would be wise to pay attention to what is shared in this article. Distilled biodiesel has the potential to make a material difference for your business. That’s primarily because of the benefits of a distilled product, but also because it’s a relatively new method of biodiesel purification, and knowing about it can give you a leg up on the competition.
The following are three key advantages of distilled biodiesel:
- Superior cold-weather performance
- Greater feedstock flexibility, which can ease supply and price issues and allow for lower carbon intensity (CI) scores
- Increased purity and easier to blend
We’ll dive into each advantage in more detail below, but first, let’s review the distillation process.
What Is Distillation?
Distillation is the process of purifying a liquid using evaporation and condensation. Whether it’s fuel, alcohol or water, the goal is to get certain molecules out of the product to purify it. You may be familiar with this in petroleum refining, where crude oil is heated to cause sets of molecules to evaporate from the liquid oil. These are the cuts that, when recondensed, result in propane, gasoline, diesel and heavier fuel oils.
With biodiesel, distillation involves creating conditions that turn fatty acid methyl esters (FAME)—the molecules that make up biodiesel—from a liquid to a gas so they can be removed. Then the product is converted back to a liquid in a more purified form. Left behind in the distillation bottoms are minor components that can contribute to filter plugging.
How Distillation Is Different
You may be wondering how distillation differs from how biodiesel is usually purified. The most common traditional method is known as cold filtration. For example, Renewable Energy Group (REG) has a patented cold filtration process in which crude methyl esters are chilled to a certain temperature. A filter aid is added, and between that and the chilling process, minor components are removed.
To be clear, cold filtration is still a good way to purify biodiesel, but distillation has some additional advantages. Those advantages were listed above, and now we’ll explore them further.
Superior Cold-Weather Performance
First is cold-weather performance. Cloud point is one of the most commonly heard terms in the biodiesel industry. Far too often we hear from people who believe it is the only thing that matters when using biodiesel in the cold, and that vegetable-oil-based biodiesel is better because it has a low cloud point. Distillation shows why that notion is wrong.
This goes back to the great job distillation does to remove filter-plugging minor components, such as steryl glucosides. With those components taken out of the product, distilled biodiesel can outperform an undistilled product, even at a higher cloud point.
The ability to create high-quality biodiesel from a variety of feedstocks—feedstock flexibility, as we call it at REG—has two primary advantages. One is it can provide more nimbleness in the commodity markets. If a particular feedstock is experiencing price or supply fluctuations, we can turn to another feedstock and know that our end product will still meet ASTM and customer specifications. This, of course, is good for our customers too.
Another advantage of feedstock flexibility is the ability to make biodiesel from feedstocks such as animal fat, used cooking oil and inedible corn oil, which can allow for lower CI scores. Some of the feedstocks with favorable CI scores can result in biodiesel with a higher cloud point, but with cloud point being less of an issue with a distilled product, users can get a fuel with lower CI that also performs well in cold weather.
Carbon intensity is important because it helps companies meet their sustainability goals. And, if you are doing in business on the West Coast in California or Oregon, it is critical due to those states’ low-carbon fuel standard policies.
The removal of minor components in distillation has one more benefit: it helps create the purest form of biodiesel. The enhanced purity also helps distilled biodiesel blend more easily with petroleum diesel.
Cold-weather performance, feedstock flexibility and purity—simply stated, those are three significant reasons to try distilled biodiesel.
Jon Scharingson oversees the sales and marketing efforts for Renewable Energy Group, Inc. (REG), a leading biodiesel producer. Contact Jon at Jon.Scharingson@REGI.com, or for more information about REG, visit REGI.com. To learn more about this subject, read this white paper.