by Tamara Scully
Two recent informational webinars highlighted exactly how much oilseed research has been happening in the Northeast. Vermont’s Bioenergy Initiative co-sponsored a Cornell Small Farms webinar featuring biofuel production at Roger Rainville’s Borderview Farm in Alburgh, VT. University of Vermont Agriculture Extension Engineer Chris Callahan recently joined Penn State’s Doug Schaufler, Research Associate, Ag Bio Engineering, in presenting another webinar, focusing on oilseed production and processing. Researchers at both universities have been working together on several projects involving oilseed crops.
Oilseeds include canola, soybean, sunflower, flax and lesser known crops such as camelina, and mustard. Extracting the oil via pressing the seeds also leaves behind meal, which can be utilized as livestock feed, as well as a natural fertilizer and weed control agent. It can be burned in pellet stoves, making oilseed crops fully functional as an alternative energy source.
“The neighbors really like the sunflowers when they are growing,” Roger Rainville said. While that may be a fringe benefit, the downside is that the birds are partial to sunflower seeds, too, and “can take the whole crop out.”
Rainville is looking at varying planting dates to see if early or late planting can affect just how much bird pressure the crop receives. Another issue is powdery mildew. Rotating the crops every year, and using a four year field rotation can help prevent powdery mildew problems, he said.
Rainville has been growing and pressing sunflower seed on his former dairy farm, and processing it into biodiesel and animal feed for on-farm use since 2005. While he has grown and used canola, “the harvesting time with sunflowers” works out better for his farm’s needs, he explained.
Rainville altered a combine with a inexpensive fix — using 2 by 4s and plastic to fashion a V-shaped prong attached beneath the combine — to better harvest the seedheads, as a grain head did not work well. He now has “very little field loss.”
The harvested seeds are put into a 60 ton dry bin, where a blower underneath blows air to cool and dry them. Because sunflowers are very flammable, heat drying does not work. Harvested at 16 percent moisture, the sunflower seeds need to be stored at about 10 percent moisture, Rainville said, to prevent fermentation. Canola has to be harvested at an even higher moisture level to prevent pod shattering, but requires storage moisture levels of 9 percent.
Seeds are cleaned with a rotary seed cleaner. Rainville uses 100 year old Clipper Cleaner Fan Mills. Unlike canola, whose seeds are uniform in size, sunflower seeds are variable, and the screens need to be changed to clean seeds of different sizes.
Dried sunflower seeds go into 1-ton bags. They will pick up moisture form the air, and inexpensive aerators, designed for grain bins, are used to prevent this. He has never lost more than 10 percent of the seed.
Oil is extracted from the seeds using pressure. The presses consist of a hopper to receive the seed, an electric motor to run the press, and a heater to increase the temperature of the seeds during pressing. The pressure crushes the seeds, releasing the oil. One ton of sunflower seed is 38 percent oil and 62 percent meal when processed, Callahan said.
Penn State and the University of Vermont jointly evaluated six different presses, and recorded the yields of oil at varying pressing speeds. The most oil was yielded at less-than-capacity speeds, somewhere in the mid-range.
Rainville runs his American-made oil press 24 hours/day. This processes 800 pounds of seed each day. Rainville has other presses on the farm, and says they are “all basically the same concept.”
He devotes 20 percent of his crop acreage to oilseed production, and makes enough oil to fuel all of his farm equipment. Interestingly, Rainville noted that when horses were used in the fields, hay for feed required the same 20 percent of the cropland.
“Often biofuels are spoken of as biodiesel or vegetable oil, and the two are used interchangeably,” but they are not the same,” Schaufler said. “Straight vegetable oil is just that. If you take animal fats or vegetable oils, and put them through transesterfication, you end up with biodiesel.”
While straight vegetable oil (SVO) can be utilized for fuel, it may require some modifications, as it is too thick in cold temperatures. Starting or shutting down the engine means using a petro-diesel fuel mix, due to the viscosity of the vegetable oil. Sunflower oil needs to be degummed before being used as fuel, while canola does not. Soybean oil may not be a good choice, as it deposits more solids than other vegetable oils.
“Vegetable oil is going to burn a bit differently, particularly at low loads or engine speeds,” Schaufler said.
Penn State has run two pieces of diesel equipment — a front loader and a tractor — on SVO for over 1,000 hours each. The front end loader was started and stopped a lot for brief tasks, and never really warmed up, so required almost as much diesel fuel use as vegetable oil use. The front loader, on the other hand, used 3,428 gallons of SVO, and only 628 gallon of diesel fuel during 1,370 hours of use.
Biodiesel, refined from SVO, requires several steps. Water may need to be removed. The oil undergoes filtering to remove sediment, and a transesterfication reaction requires a catalyst in the form of lye — typically sodium or potassium hydroxide — to cause a reaction whereby added alcohol reacts with the vegetable oil, forming biodiesel.
After the conversion, the alcohol — typical methanol — is recovered in a distillation process. Glycerin, a by-product, settles out of the fuel and is removed, and the fuel is cleaned. The fuel needs to pass a quality specification to qualify as biodiesel, appropriate for use in unmodified diesel engines.
At Borderview Farm, an automated 50 gallon biodiesel processing system is used. The ingredients — lye and methanol — are added to oil which has been heated, and transesterfication occurs. Next, sawdust is used to absorb any lye left in the fuel, while water and methanol are absorbed with pellets. The by-product of glycerin is stored in 250 gallon totes.
“What to do with our glycerin is still an issue,” Rainville said. “Transportation to the few places that will buy it is prohibitive.”
Sodium or potassium hydroxide, glycerin and oilseed meal are all by-products of the biodiesel production process. Sodium hydroxide is being studied as a feed additive for cattle. Studies are now being done to determine how glycerin can best be utilized. One option, being studied by the University of Wisconsin, is as a feed ingredient. One pound of glycerin has the same energy as three pounds of corn, Rainville said.
The oilseed meal is also used as an economical cattle feed. And, if it goes moldy, it can be burned in a pellet stove. According to Rainvill, the meal provides more than 1,000 BTUs of energy above what is generated by hardwood pellets.
The cost of growing and processing biodiesel on-farm varies, Callahan said, based on acreage, cultural practices and crop grown. The University of Vermont offers a cost and profit calculator specifically geared towards biodiesel production.
“It’s fairly inexpensive to do,” Rainville said, encouraging anyone interested in biodiesel processing to consider doing so.
Small scale oilseed production in the Northeast
by Tamara Scully