Engineering development of advanced physical fine coal cleaning for premium fuel applications. Quarterly technical progress report 13, October--December, 1995

The primary goal of this project is the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope includes laboratory research and bench-scale testing on six coals to optimize these processes, followed by the design, construction, and operation of a 2-t/hr process development unit. During Quarter 13 (October--December 1995), testing of the GranuFlow dewatering process indicated a 3--4% reduction in cake moisture for screen-bowl and solid-bowl centrifuge products. The Orimulsion additions were also found to reduce the potential dustiness of the fine coal, as well as improve solids recovery in the screen-bowl centrifuge. Based on these results, Lady Dunn management now plans to use a screen bowl centrifuge to dewater their Microcel{trademark} column froth product. Subtask 3.3 testing, investigating a novel Hydrophobic Dewatering process (HD), continued this quarter. Continuing Subtask 6.4 work, investigating coal-water-slurry formulation, indicated that selective agglomeration products can be formulated into slurries with lower viscosities than advanced flotation products. Subtask 6.5 agglomeration bench-scale testing results indicate that a very fine grind is required to meet the 2 lb ash/MBtu product specification for the Winifrede coal, while the Hiawatha coal requires a grind in the 100- to 150-mesh topsize range. Detailed design work remaining involves the preparation and issuing of the final task report. Utilizing this detailed design, a construction bid package was prepared and submitted to three Colorado based contractors for quotes as part of Task 9