An ARI professor helps a Midwestern coal company with mineral deposit problems that affects its coal.

Dr. John Pohl, an ARI professor of mechanical and mining and mineral engineering, has worked to determine why the coal at the Midwestern company is creating deposits and to recommend solutions.

The problem lies with the coal itself—specific train loads of coal have produced slagging and fouling deposits, Pohl said.  Slag, a molten deposit of minerals that occurs in the radiant section of the boiler usually above the flame, and fouling, a sintered deposit of minerals usually occurs in the cooler convective pass of the boiler, are types of deposits that have caused several operability problems for the utility.

Slag and fouling deposits decrease the efficiency of the boiler by reducing heat transfers, increasing air fan pressure and creating deposits that may damage water tubes in the boiler and clog the disposal hopper.

Deposits produced from coal reduce the availability of the boiler, or the amount of time the boiler is able to operate at a desired load, thus decreasing output. The problem also decreases efficiency, or thermal energy input transferred to output or steam.

After examining the problem, Pohl has determined three solutions. The first, which is a temporary solution that is usually not accepted by the utility, is to simply reduce the load of coal being fired each day. The second solution is to blend the deposition coal with other coal free of deposits. And, the third solution is to introduce a mineral additive to the boiler.

The additive solution is the most probable answer, Pohl said. By adding vermiculite, a member of the phyllosilicate group of minerals, resembling mica in appearance with flakes of material, the chemical and physical nature of the deposit changes. The deposit it weakened and the melting point is increased, thus lessening the problems caused when difficult deposits form.

For more information about this project, and mining and mineral engineering, as well as mechanical engineering, please contact Dr. John Pohl at jpohl@vt.edu

The molten end of slag deposits are created when individual particles melt and dissolve into uniform molten mixtures.

The First Annual Virginia Tech at Northern Virginia Research Exposition was well attended by ARI faculty and students.

ARI faculty and students displayed 21 of the over 50 displayed research posters, Thursday, April 17, 2003 at the Northern Virginia Graduate Center in Falls Church.

The program began with a welcome from NVC Director, Karen Akers.  Speakers included Mark McNamee, university provost and vice president of academic affairs; James Bohland, executive director of northern Virginia programs; Michael J. Martin, executive vice president Virginia Tech Intellectual Properties, Inc.; and Nick Stone, director of education, International Institute for Information Technology (IIIT).

As the opening speaker, Bohland welcomed new faculty and students as well expressing appreciation for the Expo. He said he believed the Expo was part of a link helping the main campus in Blacksburg to better understand extended campuses in the Northern Virginia area.

Also expressing gratitude for the event, McNamee said the event was a special combination of efforts provided by students, faculty and administration to combine education and research.

He said Virginia Tech would have to “think beyond Blacksburg” to compete in an international arena and to operate in a global environment.  He also explained the university strives to prepare students to become leaders and critical thinkers in their respective fields.

The concluding two speakers, Martin and Stone, expressed views on the value of protecting intellectual research and the importance of cooperation among researchers.

Following the program, visitors and VT affiliates were invited to view research projects presented in the form of posters.

For a photo gallery of the event, please visit: http://www.ari.vt.edu/nvcXpo.htm