Virginia Tech set to clean up

The US Department of Energy (DOE) has awarded a US$7.9 million contract to Virginia Tech’s Centre for Coal and Minerals Processing (CCMP) to demonstrate the commercial potential of new coal production techniques.

Although companies have mined coal on a large scale since the Industrial Revolution, they still must discard a significant portion of the coal fines generated during the mining operations due to the difficulty in cleaning and handling.

The DOE estimates that more than 2.5 billion discarded tons of fine coal sits in various sites around the US.

The contract is said to provide for industry to test two different processes that may solve this environmental problem.

The technologies, developed by minerals engineers at Virginia Tech, will be tested at four locations, including one of the largest coal preparation plants in the US, owned by CONSOL Energy.

‘Our dewatering technology allows coal companies to recover coal from waste products. We kill two birds with one stone,’ said Roe-Hoan Yoon, Virginia Tech mining and minerals engineering (MinE) professor and CCMP director. ‘The process recovers valuable coal from waste and, at the same time, eliminates fine coal impoundments that are a significant environmental concern.’

Processing fine coal is the most difficult and costly part of producing the solid fuel, said Yoon.

Impurities such as sulphur and other mineral matter are removed from the coal by washing it in water. However, the cost of separating water from the fine coal particles made during processing is said to be too high. Consequently, many coal producers are forced to discard the fines to impoundments and recover only the coarse coal.

Virginia Tech’s new technologies will now allow coal companies to remove the water from fine coal efficiently, and to recover high-quality solid fuels from the waste streams.

‘The costs of implementing the new technologies are low,’ Yoon said, ‘and their commercial application will not entail environmental problems.’

Yoon’s prediction of a low cost for implementation is based on case studies performed by his research centre during the Phase I portion of this work, also funded by the DOE.

One Phase I case study conducted on a Virginia coal company showed that it could increase its revenue by $3.4 million a year using the new technology by removing only one third of the water left in the fine coal. If one half of the water is removed, then the figure jumps to $4.6 million.

The new funding award to Virginia Tech is a continuation of the DOE’s Solid Fuels and Feedstocks Grand Challenge program.

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