Development of an Advanced Fine Coal Suspension Dewatering Process

  • Parekh, Bhupendra (PI)
  • Tao, Dongping (CoI)

Grants and Contracts Details

Description

With the advancement in fine coal cleaning technology, recovery of fine coal (minus 28 mesh) has become an attractive route for the U.S. coal industry. The clean coal recovered using the advanced flotation technology i.e. column flotation, contains on average 20% solids and 80% water, with an average particle size of 35 microns. It is difficult to dewater this fine clean coal slurry to about 20% moisture level using the conventional dewatering techniques. The finer the particle, the larger the surface area and thus, it retains large amounts of moisture on the surface. The coal industry has shown some reluctance in using the advanced coal recovery techniques, because of unavailability of an economical dewatering technique which can provide a product containing less than 20% moisture. U.S.DOE and Industry has identified the dewatering of coal fines as a high priority problem. For the last ten years, the University of Kentucky has been involved in developing and evaluating methods to help solving the fine coal slurry dewatering problem. This proposal describes the concept of a newly developed mechanical dewatering process which has shown potential in providing a low moisture product. The goal of the proposed program is to evaluate a novel two stage dewatering process developed at the University of Kentucky. It involves the utilization of two forces, namely, vacuum and pressure for dewatering of fine coal slurries. It was observed that a filter cake formed under vacuum has a porous structure with capillaries containing free water. When this porous cake is subjected to pressure for a short time, the free water present in the filter cake flows out. Laboratory studies have shown that depending on the coal type a filter cake containing about 10% moisture could be obtained using the two-stage filtration technique. It was also noted that applying intermittent breaks in vacuum force during cake formation, which disturbed the cake structure, helped in removing moisture from the filter cakes. In response to the Energy Efficiency Renewable Energy (EERE)-Industrial Technologies Program (ITP) Mining Industry of the Future Grand Challenge Technology Concept for Mining Industry call for proposals in the area of Energy Efficient Alternatives to Current Technologies in Beneficiation and Processing, the proposed project is submitted as a step to the grand challenge with Phase I activities. The proposed program will conduct dewatering tests of at least two different fine coal slurries obtained from the industrial partner's coal preparation plants. It is anticipated that through this process significant energy savings will be achieved for the U.S. coal industry.
StatusFinished
Effective start/end date7/1/054/30/08

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