That dual-stream, single-pass harvesting system was developed by Stuart Birrell, an Iowa State associate professor of agricultural and biosystems engineering, and graduate students Mark Dilts and Ben Schlesser. They're working to design, build and test machinery that will harvest corn stover -- the stalks, cobs and leaves -- when farmers bring in their grain. The stover could be the source of plant fiber that feeds the next generation of ethanol plants.
The researchers ran their latest version of a stover harvester through about 50 acres of corn near Ames this fall. Birrell recently showed some video of the tests on his office computer and explained how the system works.
The researchers are developing stover attachments that can be used on standard combines. The result would be an additional cost to farmers of about $10,000 to $15,000 instead of the six figures it would take for a separate combine to harvest stover. The attachments would also allow farmers to harvest grain and stover with one pass through a field.
The system the researchers have come up with includes a modified row crop header and corn reel attached to the front of the combine and a chopper and blower attached to the back.
The header and reel feed leaves and stalks into the combine so the biomass can be harvested before it touches the ground and is contaminated with soil. The chopper cuts stover into 2-inch pieces. And the blower throws the chopped stover into a wagon.
Although tests with the prototype machine have been successful, Birrell said there is more development work to do:
Harvest capacity. The stover harvesting equipment is capable of speeds equal to a normal grain harvest when less than 50 percent of the stover is collected. When all of a field's stover is collected, harvest speeds are about half of a normal grain harvest. Birrell said that would be unacceptable to farmers. And so he's working to get the speed to at least 80 percent of a normal grain harvest -- no matter how much stover is collected. That would allow farmers to decide how much stover they want to harvest without significantly affecting the time it takes to harvest their fields.
Transportation. Birrell said researchers need to figure out how to pack the harvested stover so it can be economically transported. He said stover comes off the combine at a density of about 3 to 4 pounds per cubic foot; it needs to be about 10 to 12 pounds per cubic foot for efficient trucking.
Storage. Birrell said researchers need to figure out how huge quantities of biomass can be stored. He said the U.S. Department of Energy has estimated a biorefinery would need at least 2,000 tons of biomass per day. A year's supply would cover 100 acres with 25 feet of biomass.
Fertility. Birrell said researchers need to determine how much stover can be removed from fields while still returning sufficient organic matter to the soil and protecting the soil from winter erosion.
Birrell's stover harvesting research has been supported by a three-year, $180,000 grant from the U.S. Department of Agriculture and the U.S. Department of Energy and a two-year, $50,000 grant from Deere & Company of Moline, Ill.
Birrell said development of a stover harvesting system has been constrained by a lack of research funding.
"Significant resources have been dedicated to the process of converting cellulose into ethanol," he said. "But very little has gone into answering how do you get a supply of stover from the field to the biorefinery. This will be critical to the success of the bioeconomy."
Stuart Birrell | EurekAlert!
New data unearths pesticide peril in beehives
21.04.2017 | Cornell University
New rice fights off drought
04.04.2017 | RIKEN
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
25.04.2017 | Physics and Astronomy
25.04.2017 | Materials Sciences
25.04.2017 | Life Sciences