Research HighlightsFinding Another New Use for Soybean Oil is a Blast
By Carol Brown
A Missouri researcher is conducting a study with a bang for a new way of using soybean oil.
Phillip Mulligan is a professor in mechanical and aerospace engineering at University of Missouri Science and Technology in Rolla — and he’s an explosives expert. Mulligan is leading a research project using soybean oil as a replacement for diesel fuel in the manufacture of explosives.
In the three-year project funded by the Missouri Soybean Merchandising Council, Mulligan has created a new product to replace Ammonium Nitrate Fuel Oil, known in the explosive industry as ANFO. He calls the product ANSOY, which uses a soybean oil-based fuel, and it comes with several benefits. The ANSOY performs very similar to ANFO, he says. The products are comparable in size and performance, but the soybean oil is considered biodegradable.
“In regions around the world where there has been a lot of blasting, the diesel fuel has caused a hazard to their environment,” says Mulligan. “The soil near their quarries is considered contaminated and needs to be treated because of the diesel fuel contamination. In the United States, mining operations take costly measures to minimize diesel fuel contamination and a biodegradable fuel option could go a long way to reducing their containment and reclamation costs.”
ANSOY has another performance advantage over ANFO. After an explosive blast using ammonium nitrate, nitrous oxide gas is formed and can produce a noxious red cloud if there is a high enough concentration of the gas, Mulligan says, but with the ANSOY product, the poisonous gases are reduced.
After a blast, both ANFO and ANSOY produce particles that settle out of the air and onto the ground. However, the ongoing study indicates the ANSOY particles are larger, so they settle faster, reducing how far the post-detonation gases travel from the blast.
In addition to environmental benefits, there are economic benefits as well — good news for soybean growers.
“The mining industry is the biggest consumer of explosives in the United States, using three and a half billion pounds of explosives every year,” Mulligan comments. “The primary explosive used is ANFO. If the industry switched to a soybean oil-based explosive, it could mean about 30.5 million gallons of soybean oil could be used annually.”
Mulligan also has run the numbers on cost comparisons between diesel fuel and soy oil. Over the last 13 years, using the lowest price between the two, the mining explosives industry could have saved nearly $364 million by using soy-based explosives.
The environmental and cost benefits show positives for using soy-based explosives. But what about performance? Mulligan says that ANSOY performs as well as the ANFO.
“Without getting too technical, what makes a difference in performance is the diameter of the explosive and its confinement — whether it’s encased in steel or rock,” he says. “We find with ANSOY, we need a slightly larger drill hole (2 inches compared to 1.5 inches), but its energy output is slightly higher than ANFO. The ratios of fuel used to make the explosives are close to one-to-one.”
Mulligan and his students are working on the next phase in this final year of the research project, which is to make ANSOY into an emulsified explosive so it can be water resistant, a necessary component for the mining industry. The original makeup of ANFO and ANSOY consists of small beads or pearls. They are adding a gel to the ANSOY, making a consistency like toothpaste, to create the emulsification.
“In a rock quarry, for example, drillers will go in a week ahead and drill some 100 holes for the explosives. Then it rains and those holes collect water. Neither ANFO nor ANSOY can be used, as they will dissolve in the water-filled holes,” Mulligan explains. “That’s where the water-resistant emulsified explosive can be used.”
Mulligan identifies with both explosives and soybeans. He grew up on a farm in Iowa, where his family grows corn, soybeans and raises pigs. He also experienced mining firsthand as his grandparents leased some of their land to a quarry.
“I got to help at the quarry doing some drilling and helping to load the holes,” Mulligan says. “I recorded the shots on my VHS camcorder and would watch them in slow motion, which got me interested in pursuing this as a career.”
Mulligan can tie his rural roots to his career, which could be advantageous for both the mining and the agriculture industries. As his soybean oil-based explosives are developed, soybean farmers can benefit from this new market and the explosives industry can further reduce the environmental side effects of petroleum-based products.
Published: May 23, 2022
This project was funded by the soybean checkoff. To find research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.