Making Drier Coal

One way to burn coal with fewer emissions, less waste and lower maintenance costs is to reduce the amount of moisture in it prior to firing. This is particularly true for the low-grade lignite coal found in North Dakota, where the moisture content typically ranges between 25 and 40 percent. In the past several weeks, two companies in the state have moved to the forefront of coal drying technology applications.

Great River Energy

The Bismarck Tribune reported over the weekend that the coal drying project at Great River Energy's Coal Creek Station near Underwood went online in December after years of design and development. According to the article, the dryers remove approximately 25% of the moisture from the lignite that fires the plant.

Great River has applied for patents on the technology, so details provided by the Tribune are sketchy. The eight dryers reportedly are housed inside a nine-story strucure that was added on to the existing plant and use approximately 300 degrees of heat from the plant for the drying process. Conveyors are used to take the coal to the dryers and then to the firing units.

Part of the project's cost was covered by a Department of Energy grant. Great River Energy has been working closely with the DOE for nearly a decade on the project. The two entities published the results of their initial research in 2006.

GTL Energy

Meanwhile, a shipment of lignite from New Zealand was due to arrive this month at the newly-constructed coal drying plant located west of Dickinson. The plant, operated by Australian-based GTL Energy, aims to reduce lignite water content to 10 percent using a process called benefication and is the first commercial-scale project of its kind.

GTL hopes to process about 240,000 tons of lignite annually at full capacity, although its unclear at this point where the coal will come from. The New Zealand shipment is intended only to test the plant's performance in order to determine if a similar plant would be economically feasible in New Zealand.

The GTL facility originally was constructed as part of a larger plan that included a lignite coal mine and a 500 MW coal-fired electric generating plant. The plans for the latter two were dropped in August 2007, however, after objections were raised based on the project's proximity to the nearby Theodore Roosevelt National Park.

The developer of the power plant, Great Northern Power Development, then announced in January 2008 that it was going to build a coal gasification plant at the site. These plans were then changed to a coal-to-hydrogen plant in July 2009, a move supported by the North Dakota Industrial Commission which has committed $10 million in state funds to the project. A construction permit application for the plant and the coal mine has not yet been filed with the state, however, and strong environmental objections are likely to be raised when it is.

An update is likely when GTL announces more details on the New Zealand coal shipment.