Biomass blockages at ethanol refineries

Energy companies have invested a lot in the potential of creating fuel from biomass, the leftover plant material from harvesting corn and other crops. But there's an unexpected problem -- moving the stuff through a pipe.



“If you send a fluid through a pipe, it flows exactly where you want it to go,” says Nathan Gasteyer, a graduate student working under professor Carl Wassgren and assistant professor Marcial Gonzalez.  “But this corn stover is grainy, fibrous material that behaves very differently.”

Corn stover is the material left over from a corn harvest that usually gets discarded: stalks, leaves, husks, and other parts of the plant.  Scientists believe there is great potential in converting this biomass into usable fuel, such as ethanol.  But before it’s processed, it must be moved.  And that’s the bottleneck Nathan’s team is trying to tackle.

“Right now whenever they’re designing equipment, they have to include a door where people can get in there with a stick, or sometimes even a jackhammer, to break up the material when it jams up,” says Nathan.  “70% of the downtime at these refineries is caused by just feeding the material into the facility.”

Solving this problem requires a deep dive into solid mechanics.  “To make it flowable, we first have to determine this material’s properties,” says Nathan.  “Its moisture content, its tensile strength, its rheology [flowing properties], its tribology [friction between particles].  We need a lot of instrumented devices to fully understand the material.”

That’s where Purdue’s Center for Particulate Products and Processes (CP3) comes in. Located in the Flex Lab, CP3 is the most comprehensive academic lab in the country for studying particles, powders, and compacts.

“This is really a solid mechanics researcher’s dream!” laughs Nathan.  “I can put a sample in our material tester and get its compressive strength.  I can run breakage tests.  I can examine the shear strength, which is how much force it takes to get it to flow sideways.  Any regime of measurement, with any size of powder or particle, we can do it here.”

Most of all, Nathan appreciates the combination of pure science and practical application.  “We’re working with a very practical material and a very practical application,” he says, “The numbers we measure in this lab are going right out to the refineries to be used in a real system.  We are a true bridge between raw science and real-world usage.  And it’s the people in this lab that are growing that understanding day by day.”

Learn more about Purdue's work with particles at the Center for Particulate Products and Processes (CP3):

Writer: Jared Pike,, 765-496-0374