Featured Research

from universities, journals, and other organizations

Energy wasted grinding switchgrass smaller to improve flowability

Date:
April 12, 2010
Source:
Purdue University
Summary:
Biofuels processors who mill switchgrass into fine bits to help its flowability should be able to save time, energy and money by not doing so, a new study shows.

Biofuels processors who mill switchgrass into fine bits to help its flowability should be able to save time, energy and money by not doing so, a Purdue University study shows.

Related Articles


Switchgrass can be used in a number of biofuel applications, but moving it -- especially feeding it into boilers -- can be problematic, said Klein Ileleji, an assistant professor of agricultural and biological engineering. While corn and soybeans are round and spherical, switchgrass is shaped more like matchsticks, causing pieces to interlock and disrupt its ability to flow. Those blockages cost time and can be dangerous for those tasked with breaking the clog, he said.

"In any facility -- in a power plant or in a processing facility -- when you have a blockage, it's a processing nightmare," said Ileleji, whose findings are in the current issue of the journal Transactions of the ASABE.

Ileleji compared circularity, roundness and aspect ratio for corn, soybean and switchgrass that had been hammermilled to three different sizes. Aspect ratio, which has the greatest effect on the ability of switchgrass to flow, is the ratio of a switchgrass particle's length to its width.

Conventional wisdom held that grinding switchgrass into smaller pieces would bring its aspect ratio closer to that of corn and soybeans, which have ratios close to 1 and no problems with flowability.

"Switchgrass is not a good flowable feedstock. You would think grinding it smaller would help," Ileleji said. "But grinding does not necessarily change the morphological characteristics in switchgrass that are important for flow."

Ileleji's testing showed that hammermilling -- one of the most common grinding techniques, which beats and breaks biomass until it is small enough to pass through screens -- breaks switchgrass in a way that keeps its aspect ratio about the same no matter the size. Unless the switchgrass is milled into a powder, those high aspect ratios would keep causing switchgrass to interlock and clog in bulk flow.

Ileleji said processors could save money with the information because they can stop hammermilling switchgrass when it fits through a 6.4 mm screen, the largest Ileleji tested.

"Grinding consumes a lot of energy. It is one of the highest energy costs in a processing facility," Ileleji said. "It's better to grind switchgrass through a 6.4 mm screen than to use more energy to grind through a smaller screen expecting that its handling characteristics would be improved dramatically."

Ileleji said he would study flow behavior of switchgrass through hoppers to try to find ways to keep it from creating blockages. Duke Energy and the Purdue Energy Center funded his research, which is part of his doctoral student Cedric Ogden's research on the flow mechanics of switchgrass bulk solid in hoppers under gravity discharge.


Story Source:

The above story is based on materials provided by Purdue University. Note: Materials may be edited for content and length.


Cite This Page:

Purdue University. "Energy wasted grinding switchgrass smaller to improve flowability." ScienceDaily. ScienceDaily, 12 April 2010. <www.sciencedaily.com/releases/2010/04/100412172837.htm>.
Purdue University. (2010, April 12). Energy wasted grinding switchgrass smaller to improve flowability. ScienceDaily. Retrieved March 6, 2015 from www.sciencedaily.com/releases/2010/04/100412172837.htm
Purdue University. "Energy wasted grinding switchgrass smaller to improve flowability." ScienceDaily. www.sciencedaily.com/releases/2010/04/100412172837.htm (accessed March 6, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Friday, March 6, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

'Extinct' Bird Isn't Extinct At All, Scientists Find

'Extinct' Bird Isn't Extinct At All, Scientists Find

Buzz60 (Mar. 6, 2015) — Scientists rediscover a bird thought to be extinct, so we may be able to cross it off the "Gone For Good" list. Sean Dowling (@seandowlingtv) has more details. Video provided by Buzz60
Powered by NewsLook.com
China's Toxic Truth Goes Viral

China's Toxic Truth Goes Viral

Reuters - Business Video Online (Mar. 6, 2015) — Pollution in China has gone viral with a documentary highlighting the problems caused by major industries. But awareness may not be enough to clean up dirty producers. Jane Lanhee Lee reports. Video provided by Reuters
Powered by NewsLook.com
Lack of Snow Pushes Alaska Sled Dog Race North

Lack of Snow Pushes Alaska Sled Dog Race North

AP (Mar. 6, 2015) — A shortage of snow has forced Alaska&apos;s Iditarod Trail Sled Dog Race to move 300 miles north to Fairbanks. The ceremonial start through downtown Anchorage will take place this weekend, using snow stockpiled earlier this winter. (March 6) Video provided by AP
Powered by NewsLook.com
Why Were El Niño Predictions So Far Off Base?

Why Were El Niño Predictions So Far Off Base?

Newsy (Mar. 5, 2015) — Weather agencies say an El Niño event is officially underway, but they called for it months ago and warned it would be way stronger than it is. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins