Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Coal Dewatering Technology Turns Sludge to Powder

10.02.2009
The ultrafine coal particles that are the residue of the coal cleaning process have been discarded into hundreds of impoundments. Now, a dewatering technology developed at Virginia Tech has succeeded in reducing the moisture content of ultrafine coal to less than 20 percent.

Because there has been no economically viable technology to remove water from ultrafine coal slurries, the ultrafine particles that are the residue of the coal cleaning process have been discarded into hundreds of impoundments.

Now, Peter Bethell of Arch Coal Inc. reports that a dewatering technology developed at Virginia Tech has succeeded in reducing the moisture content of ultrafine coal to less than 20 percent, transforming it to a salable product.

With funding from the National Energy Technology Laboratory (NETL), Roe-Hoan Yoon (www.mining.vt.edu/facultystaff/yoon.htm), the Nicholas T. Camicia Professor of Mining and Mineral Engineering at Virginia Tech, and his colleagues have developed a hyperbaric centrifuge that can efficiently dewater coal as fine as talcum powder. Such coal fines presently must be discarded by even the most advanced coal cleaning plants because its moisture content in conventional dewatering systems make it unmarketable.

"The hyperbaric centrifuge is like the spin cycle on a washing machine, with the addition of compressed air," said Yoon. "Combining increased spinning and compressed air has a synergistic effect and cuts the moisture in half compared to conventional technology."

"The results were very favorable," said Bethell, director of coal preparation at Arch. "This is material we would have had to discard; therefore, such success would mean reduced refuse in the environment and improved economic returns for the company. It also goes to energy independence because we are using more of the available resource," said Bethell.

"The Arch results mean a lot for getting the Centribaric TM technology started," said Wally Schultz, executive vice president at Decanter Machine Inc. of Johnson City, Tenn., which built the prototype unit that was used at Mingo Logan Coal Company’s Cardinal Preparation Plant, a subsidiary of Arch Coal. "The prototype unit was trailer mounted and capable of processing approximately 30 gallons per minute of feed slurry," said Schultz, who was onsite for the tests.

Decanter has been in business since the late 1980s and is the industry leader in screen-bowl centrifuge technology. "We view the Centribaric centrifuge as an extension of our product line to further recover fine coal. Previous centrifuges have not used the compressed air component," Schultz said.

"There has been no technology to economically dewater coal fines below 44 microns," said Yoon. "Now this technology can be used in conjunction with the MicrocelTM technology, developed many years ago to remove ash, to re-mine the fine coal discarded to impoundments and to help companies minimize waste generation.

"For me, that is a great accomplishment," said Yoon. "People living in coal mining districts will see fewer and smaller slurry ponds. We have done something for the industry and for the public."

"The whole purpose of cleaning coal is to reduce the ash content so that the users, usually utility companies, don't have to deal with it," said Gerald H. Luttrell (www.mining.vt.edu/facultystaff/luttrell.htm), the Massey Professor of Mining and Mineral Engineering at Virginia Tech. He added that "the lower-ash and lower-moisture coals also produce less CO2 to clean up. They burn more efficiently and thus require less coal to generate a given amount of electricity."

For this reason, Yoon and Luttrell have received $1 million in funding from the U.S. Department of State to also help the Indian coal industry produce a cleaner product (www.vtnews.vt.edu/story.php?relyear=2007&itemno=705). And the Virginia Tech researchers anticipate another project to be funded by Coal India Limited (CIL), the largest coal company in India, with the same a similar objective. The U.S. Department of Energy (DOE) has been negotiating with CIL for this project on behalf of Virginia Tech.

However, plans to install the new technology in the U.S. may be stalled. During the recent economic downturn, the price of coal dropped precipitously, which may be a barrier for immediate installation of commercial-scale units at plants. "But when the market improves, we will probably be able to justify spending the capital to install full-scale units," said Bethell, who has been working with Yoon's group for more than 20 years. "We both have Ph.D.s in similar fields, and I like to make sure that we liaise with academia so that if there is anything new we can consider using it." Bethell was the first to implement the Microcel technology.

Yoon arrived at Virginia Tech in 1979 from Canada. With funding from the U.S. Department of Energy, he and his colleagues, Luttrell and Professor Greg Adel, studied the collision between bubbles and particles in water. This fundamental study led to the development of the Microcel technology, which is used widely in the mining industry and is considered the best for cleaning fine coal. The group has developed many other technologies that are also in commercial use.

Yoon is the founding director of the Center for Advanced Separation Technology (www.cast.org.vt.edu/), a consortium of seven universities including Virginia Tech, West Virginia University, University of Kentucky, Montana Tech, University of Nevada at Reno, New Mexico Tech, and the University of Utah. Its goal is to develop advanced separation technologies as applied to energy resources and environmental control.

In October 2008, Yoon was elected to the National Academy of Engineering — the highest honor in engineering. He earned his Ph.D. in metallurgical engineering from McGill University in 1977. He obtained his bachelor's in mining engineering from Seoul National University in 1967.

DOE officials comment on the innovation here: http://www.fossil.energy.gov/news/techlines/2009/09005-DOE_Project_Yields_Patents.html

Susan Trulove | Newswise Science News
Further information:
http://www.vt.edu

More articles from Process Engineering:

nachricht CeGlaFlex project: wafer-thin, unbreakable and flexible ceramic and glass
25.04.2017 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Additive manufacturing, from macro to nano
11.04.2017 | Laser Zentrum Hannover e.V.

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

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...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

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...

Im Focus: Deep inside Galaxy M87

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...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

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...

Im Focus: Microprocessors based on a layer of just three atoms

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>