Premium Fuel Production From Mining and Timber Waste Using Advanced Separation and Pelletizing Technologies

Grants and Contracts Details

Description

Due in part to the third lowest energy costs in the United States, the Commonwealth of Kentucky has a concentration of high energy consuming industries. The reason for the low energy costs is the close proximity of the utilities to the coal producing regions of the state, whose coal production is the nation's third largest. According to the Office of Industrial Technologies in the U.S. Department of Energy (USDOE), the Mining and Wood & Timber industries are two of seven industries that have been identified as consuming the greatest amount of energy and both are major producers in Kentucky. The Timber industry is the largest of any state east of the Mississippi River with a production of nearly 300 million feet boards of lumber annually. Both industries produce a considerable amount of waste material that contains a significant amount of energy. It is estimated that the coal operations current dispose 3 million tons annually of minus 100-mesh high energy (12,000 Btu/lb) coal due to cleaning, dewatering and handleability concerns. Despite the ability to use the sawdust waste from lumber production as a industrial fuel, the eastern Kentucky producers are forced to store approximately 100,000 tons on the surface of the lumber operations due to modest heat values (3000 - 6000 Btu/Ib), high transportation costs and long haulage distances to industrial sites. The goal of the proposed project is to develop a premium fuel from the waste materials created from the production of coal and lumber. The fine coal obtained from coal refuse ponds will be cleaned using advanced separation technologies and then dewatered to lower moisture levels than currently realized by adding wood fibers utilizing an enhanced dewatering technique. The clean coal and sawdust will be combined at a ratio of about 90-to-1O and reconstituted (extruded or briquettes) to form a utility fuel that can be easily handled through the transportation process. The close proximity of the two industries within the state minimizes transportation costs. In fact, a lumber operator and a coal mining company having adjacent properties are two of the cooperating partners in the proposed project. The project will be a joint effort between the Kentucky Division of Energy, the University of Kentucky, two coal mining companies and two lumber companies. The Kentucky Forrest Industries Association and an energy producer will also provide technical advise during the 2-year duration of the proposed project. In addition to improving the separation efficiency of fine coal recovery processes, the project proposes to evaluate and optimize the use of sawdust during the upgrading of fine coal. Preliminary studies have shown that the addition of sawdust and other wood fibers could reduce the moisture content of a dewatered filter cake by an absolute 6 percentage points while also enhancing the strength of the briquettes formed from an agglomeration process. Various wood types and their aging effects will be investigated in an effort to understand the fundamental aspects of both the dewatering and briquetting process. The binder represents a significant cost in the briquetting process for coal and it is believed that the quantity can be reduced by the sawdust addition. However, to further enhance the economics, the concept of using all or a portion of the binder amount to substitute for the chemicals used during cleaning and dewatering will be explored. A previous study revealed that a tall oil derivative is an effective binder agent and tall oil is a well-known additive in froth flotation, which is a commonly employed process for recovering fine coal. After completion of the project tasks, a detailed economic evaluation of the total process will be conducted. If proven favorable, the process will produce a fuel having an energy value of around 9000 - 10,000 Btu/lb from material that is currently disposed in refuse ponds and landfills. The state would realize an annual energy recovery of 842 billion Btu from sawdust while 69,600 billion Btu would be obtained from the fine coal currently being disposed. Based on an average cost of 1.20 $/MMBtu, the total increased revenue would be $84.5 million annually. Potential also exists for significant energy recovery from active or abandoned refuse ponds. In addition to the energy gains, the use of wood as an energy source effectively reduces CO2 emissions. Negative environmental aspects of surface disposal of sawdust and the increased life of current refuse pond impoundments represent significant positive benefits resulting from the successful completion of the proposed project.
StatusFinished
Effective start/end date7/1/026/30/05

Funding

  • KY Natural Resources Environmental Protection Cabinet: $501,730.00

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