Richard P. Killmeyer

Physical cleaning of high carbon fly ash

An industrial fly ash sample was cleaned by three different processes, which were triboelectrostatic separation, ultrasonic column agglomeration, and column flotation. The unburned carbon concentrates were collected at purities ranging up to 62% at recoveries of 62%. In addition, optical microscopy studies were conducted on the final carbon concentrates to determine the carbon forms (inertinite, isotropic coke and anisotropic coke) collected from these various physical-cleaning processes. The effects of the various cleaning processes on the production of different carbon forms from high carbon fly ashes will be discussed.

Centrifugal float-sink testing of fine coal: An interlaboratory test program

The Pittsburgh Energy Technology Center (PETC) recently completed an interlaboratory test program (ITP) involving eight laboratories that are currently performing washability analyses of coals finer than 500-microns top size using a centrifugal float-sink technique. With current and future development of fine coal cleaning technology, there is a growing need to determine the washability of coals in extremely fine sizes, in some cases as fine as several microns by zero. However, much uncertainty exists about limitations relative to particle size and the viability of centrifugal float-sink procedures in achieving “ideal” specific gravity separations (i.e., the perfect separation of particles according to their density). The objective of this work was to develop an understanding regarding the variables affecting the procedure and initiate a process for obtaining a standard procedure. A Pittsburgh No. 8 coal from Belmont County, Ohio, was ground to four different top sizes: 217, 83, 48, and 14 microns. Two 20...

Centrifugal Dewatering and Reconstitution of Fine Coal: The GranuFlow Process

This paper describes the continuous bench-scale testing of the GranuFlow Process, developed and patented by the Pittsburgh Energy Technology Center (PETC) of the U.S. Department of Energy. Testing was conducted on both high-g force solid-bowl and screen-bowl centrifuges for dewatering and reconstitution of fine-clean-coal slurry at 300 Ib/h (136 kg/hr) in PETC7s Coal Preparation Process Research Facility. In the GranuFlow Process, fine-clean-coal slurry was treated with a bitumen emulsion before dewatering in both centrifuges. In one example, the treated products from a solid-bowl centrifuge appeared to be dry and in a free-flowing granular form, while the untreated products were wet, lumpy, sticky, and difficult to handle. Specifically, test results from the solid-bowl centrifuge indicated that the moisture content, handleability, and dust reduction of the dewatered coal product improved as the addition of emulsion increased from 2 wt% to 8 wt%. The improvement in handleability was most visible for the ...

An Evaluation of a Laboratory Wet-Drum Magnetic Separator for Micronized-Magnetite Recovery

Abstract A series of laboratory-scale tests was conducted by the U.S. Department of Energy to investigate the performance of a conventional wet-drum magnetic separator for separating micronized magnetite (-10 μm) from fine coal (-600 μm). The process variables studied included feed solids concentration, magnetite-to-coal ratio, separator feed rate, and magnetite particle size. Empirical equations were developed relating magnetite recoveries and corresponding purities to the operating conditions of the device

Performance Evaluation of Micronized-Magnetite Cycloning as a Function of Key Operational Variables, Research Report

In 1997, Custom Coals International completed a DOE contract to test the Micro-Mag Process at the continuous bench-scale at DOE’s National Energy Technology Laboratory (NETL). As a follow up to these tests, NETL conducted two series of tests to confirm the Custom Coals results and to expand upon the effects of key operational variables on cyclone performance when using magnetite that is finer than conventional Grade E magnetite. This report details the results of batch tests in which the variables were magnetite size, medium density, cyclone orifice sizes, and inlet pressure. The results show that fairly sharp separations (about 0.060-0.090 Ep) can be achieved on coal as fine as 48 x 500 mesh if magnetite that is only about twice as fine as Grade E is used at higher inlet pressures (greater than 20 psi) with the right combination of cyclone orifice sizes.

Effects of Key Operational Variables on Micronized-Magnetite Cycloning Performance

In 1997, Custom Coals International completed a DOE contract to test the Micro-Mag Process at the continuous bench-scale at DOEs National Energy Technology Laboratory (NETL). As a follow up to these tests, NETL conducted two series of tests to confirm the Custom Coals results and to expand upon the effects of key operational variables on cyclone performance when using magnetite that is finer than conventional Grade E magnetite. This paper highlights the results of batch tests using a 10 cm (4 in) diameter cyclone in which the variables were magnetite size, medium density, cyclone orifice sizes, and inlet pressure. The results show that fairly sharp separations (about 0.06-0.09 E P ) can be achieved on coal as fine as 300×25 micron (48×500 mesh) if magnetite that is only about twice as fine as Grade E is used at higher inlet pressures (greater than 138 kPa [20 psi]) with the right combination of cyclone orifice sizes.

Separation of Fly Ash Carbons by Various Cleaning Processes

An industrial fly ash sample was cleaned by three different processes, which were triboelectrostatic separation, ultrasonic column agglomeration, and column flotation, cleaned an industrial fly ash sample. The unburned carbon concentrates were collected at purities ranging up to 62% at recoveries of 62%. In addition, optical microscopy studies were conducted on the final carbon concentrates to determine the types of carbon (inertinite, isotropic coke and anisotropic coke) collected from these various cleaning processes. The effects of the various cleaning processes on the production of different carbon types from fly ash will be discussed.

A Comparison of Centrifugal Float-Sin k Testing with Alternative Methods for Determining Grade-Yield Curves of Fine Coal

Abstract This paper describes a comparison of centrifugal float-sink testing with two alternative methods for characterizing the beneficiation potential of fine coal. The alternative methods evaluated were release analysis and scanning electron microscope automated image analysis (SEM-AIA). The primary objective of this study was to compare the extent of separation measured (or predicted in the case of SEM-AIA) by each of the three techniques in terms of their respective grade-yield curves. A secondary objective of the study was to compare the separation results of two surface-based fine-coal cleaning processes [selective agglomeration and selective hydrophobic coagulation (SHC)] with the grade-yield curves of the characterization techniques The study revealed that the grade-yield curves derived from the release analysis tests indicated significantly lower mineral matter rejection values for a given yield than those from either centrifugal float-sink testing or SEM-AIA. Grade-yield curves for SEM-AIA show...