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Poc-Scale Testing of an Advanced Fine Coal Dewatering Equipment/Technique

Description: In the last quarterly report, it was noticed that the baseline dewatering data varied significantly. This abnormality was attributed to the use of house vacuum which varied significantly during the testing. This quarter tests were repeated using a portable vacuum pump which provided a constant vacuum of 25 inches of mercury. Using 30 secs cake drying time and 30 secs cake formation time, the high- and low-porosity ceramic leaf filters provided 21.5% and 18.0% filter cake moistures, respectively. The solids loading on the high- and low-porosity filters were 0.8 Kg/m 2 and 0.44 Kg/m 2 , respectively. Addition of 10 g/t of an anionic flocculant lowered the filter cake moisture from 22.0% to 14.0% using the high-porosity filter, and 18.0% to 13.5% using the low-porosity filter. Addition of 15 g/t of a cationic flocculant lowered filter cake moisture from 18.0% to 16.0% using the low-porosity filter. High-porosity filter did not provide any lowering of filter cake moisture, however, the solids loading increased from 1.5 kg/m 2 to 5.8 kg/m 2 at a flocculant dosage of 25 g/t. This high solids loading indicated thicker filter cake which would retain a high moisture. Among the three surfactants studied, only the non-ionic and the cationic were effective in lowering the filter cake moisture. 0.4 kg/t of a non-ionic surfactant (octyl phenoxy polyethoxy ethanol) lowered filter cake moisture from 19.5% to 16.8%; and 1 kg/t of the cationic surfactant CPCL, lowered the filter cake moisture from 19.0% to 15.8%. Addition of 0.4 kg/t of copper ions or 0.3 kg/t of aluminum ions lowered the filter cake moisture from 20.5% to 17.0%, using the low-porosity filter. The high-porosity filter which showed increase solids loading (thicker filter cakes) did not provide any lowering of the filter cake moisture. Low-porosity filter was found to be more effective ...
Date: October 21, 1998
Creator: Parekh, B.K.; Tao, D. & Groppo, J.G.
Partner: UNT Libraries Government Documents Department

ELECTROSTATIC SURFACE STRUCTURES OF COAL AND MINERAL PARTICLES

Description: It is the purpose of this research to study electrostatic charging mechanisms related to electrostatic beneficiation of coal with the goal of improving models of separation and the design of electrostatic separators. Areas addressed in this technical progress report are (a) electrostatic beneficiation of Pittsburgh #8 coal powders as a function of grind size and processing atmosphere; (b) the use of fluorescent micro-spheres to probe the charge distribution on the surfaces of coal particles; (c) the use of electrostatic beneficiation to recover unburned carbon from flyash; (d) the development of research instruments for investigation of charging properties of coal. Pittsburgh #8 powders were beneficiated as a function of grind size and under three atmosphere conditions: fresh ground in air , after 24 hours of air exposure, or under N2 atmosphere. The feed and processed powders were analyzed by a variety of methods including moisture, ash, total sulfur, and pyritic sulfur content. Mass distribution and cumulative charge of the processed powders were also measured. Fresh ground coal performed the best in electrostatic beneficiation. Results are compared with those of similar studies conducted on Pittsburgh #8 powders last year (April 1, 1997 to September 30, 1997). Polystyrene latex spheres were charged and deposited onto coal particles that had been passed through the electrostatic separator and collected onto insulating filters. The observations suggest bipolar charging of individual particles and patches of charge on the particles which may be associated with particular maceral types or with mineral inclusions. A preliminary investigation was performed on eletrostatic separation of unburned carbon particles from flyash. Approximately 25% of the flyash acquired positive charge in the copper tribocharger. This compares with 75% of fresh ground coal. The negatively charged material had a slightly reduced ash content suggesting some enrichment of carbonaceous material. There was also evidence that the ...
Date: December 1, 1998
Partner: UNT Libraries Government Documents Department

POC-Scale Testing of an Advanced Fine Coal Dewatering Equipment/Technique

Description: Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 mm) clean coal. Economical dewatering of an ultra-fine clean coal product to a 20% level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy's program to show that ultra-clean coal could be effectively dewatered to 20% or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 45 months beginning September 30, 1994. This report discusses technical progress made during the quarter from January 1 � March 31, 1998.
Date: August 28, 1998
Creator: Karekh, B. K.; Tao, D. & Groppo, J. G.
Partner: UNT Libraries Government Documents Department

An Advanced Control System For Fine Coal Flotation

Description: A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of ash content. Then, based on the economic and metallurgical performance of the circuit, variables such as collector dosage, frother dosage, and pulp level are adjusted using model-based control algorithms to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the ninth quarter of this project, Task 3 (Model Building and Computer Simulation) and Task 4 (Sensor Testing) were nearly completed, and Task 6 (Equipment Procurement and Installation) was initiated. Previously, data collected from the plant sampling campaign (Task 2) were used to construct a population balance model to describe the steady-state and dynamic behavior of the flotation circuit. The details of this model were presented in the Eighth Quarterly Technical Progress Report. During the past quarter, a flotation circuit simulator was designed and used to evaluate control strategies. As a result of this work, a model-based control strategy has been conceived which will allow manipulated variables to be adjusted in response to disturbances to achieve a target incremental ash value in the last cell of the bank. This will, in effect, maximize yield at an acceptable product quality. During this same period, a video-based ash analyzer was installed on the flotation tailings stream at the Moss No. 3 preparation plant. A preliminary calibration curve was established, and data are continuing to be collected in order to improve the calibration of the analyzer.
Date: August 25, 1998
Creator: Luttrell, G. H. & Adel, G. T.
Partner: UNT Libraries Government Documents Department

Combustion Characterization of Coal Fines Recovered from the Handling Plant

Description: Effect of swirl settings on NO{sub x} for three firing rates were investigated. It was found that the variation of NO{sub x} concentrations with respect to the change in swirl numbers was significant. But, the variation of NO{sub x} Concentration with respect to firing rates was found to be consistent with the increase in firing rates. The flame stability was accessed by the visual observation of the flame with relation to the burner quarl.
Date: October 1, 1996
Creator: Masudi, Houshang; Samudrala, Surender Rao; Chenevert, Lisa; Cornelius, Christopher & Dwivedi, S. N.
Partner: UNT Libraries Government Documents Department

An Advanced Control System for Fine Coal Floatation

Description: A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of ash content. Then, based on the economic and metallurgical performance of the circuit, variables such as collector dosage, frother dosage, and pulp level are adjusted using model-based control algorithms to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the eighth quarter of this project, the analysis of data collected during Task 2 (Sampling and Data Analysis) was completed, and significant progress was made on Task 3 (Model Building and Computer Simulation). Previously, a plant sampling campaign had been conducted at Pittston�s Moss No. 3 preparation plant to provide data for the development of a mathematical process model and a model-based control system. During this campaign, a one-half factorial design experiment, blocked into low and high feed rates, was conducted to investigate the effects of collector, frother, and pulp level on model parameters. In addition, samples were collected during the transient period following each change in the manipulated variables to provide data for confirmation of the dynamic process simulator. A residence time distribution (RTD) test was also conducted to estimate the mean residence time. This is a critical piece of information since no feed flowrate measurement is available, and the mean residence time can be used to estimate the feed flowrate. Feed samples were taken at timed intervals and floated in a laboratory flotation cell to investigate the magnitude of feed property disturbances and their duration.
Date: June 1, 1998
Creator: Luttrell, G. H. & Adel, G. T.
Partner: UNT Libraries Government Documents Department

Task 2.10 - Advanced Sampling and Analysis of Fine Particulates

Description: The objectives of this study are to develop a sampling method to capture the fine particulate and classiyi the particulate according to their size and chemistry. When developing the sampling method, two criteria need to be met: 1) the particulate are randomly dispersed on the sampling media and 2) the sampling media can be put directly into a scanning electron microscope (SEM) for analysis to prevent any alteration of the particulate. Several methods for the sampling and analysis of fine particulate are to be tested. Each sampling test will be analyzed using the FPT technique for collecting the size, shape, and chemical composition of 1500 to 2000 individual fine particulate. The FPT data will be classified using cluster analysis and principal component analysis to provide a classification system for these particles. As reported previously, particulate samples were collected using the advanced hybrid particulate collector (AHPC) on the inlet port of the particulate test combustor (PTC) when the Absaloka coal was burned in early April. The samples were collected at the inlet rather than the outlet port because of the loading that was expected and the temperature at which the PTC was run. Samples at the inlet were expected to see a much greater particulate loading than at the outlet because of the efficiency of the particulate collection device on the PTC. Also, polycarbonate filters cannot withstand temperatures above 230oC for long periods of time; therefore, a quick loading time was required. The samples were briefly scanned and photographed using the SEM to determine the best particulate loading time. The particulate were too close together on the 20- and 30-second polycarbonate filters to be able to analyze individual particles. The particle dispersion on the vitreous carbon substrate appeared to be the best of the four samples. Aerosols were produced from pure ...
Date: January 1, 1998
Creator: McCollor, Donald P. & Eyland, Kurt E.
Partner: UNT Libraries Government Documents Department

Coal log pipeline research at University of Missouri. 3rd quarterly report for 1995, July 1, 1995--September 30, 1995

Description: During this quarter (1/1/95-9/30/95), major progress has been made in the following areas of coal log pipeline research, development and technology transfer: (1) Conceptual design of a test machine based on hydraulic presses to mass-produce 5.4-inch-diameter coal logs for testing in a 6-inch-diameter pipeline has been completed. (2) Conceptual design of a rotary-press machine to produce 1.9-inch-diameter coal logs for testing in a 2-inch-diameter pipeline has also been completed. (3) It has been confirmed through experiments that molds with round-edge exit can make logs as good as those made with tapered exit. (4) Conducted a study to determine the effect of surface condition of mold and lubricants on the quality of coal logs. (5) Completed an evaluation of the effect of fiber (wood pulp) on coal log quality. (6) Prepared an apparatus for testing fast compaction of coal logs -- 2 second per log. (7) Compacted coal logs in a 5.3-inch-diameter mold. (8) Completed a preliminary study to assess vacuum and steam heating systems to enhance coal log production and quality. (9) Changed the small-scale-CLP-demo loop from a once-through system to a recirculating system. (10) Completed revision of CLP economic model and revised the 1993 report.
Date: December 31, 1995
Creator: Liu, H.
Partner: UNT Libraries Government Documents Department

Improvement of storage, handling, and transportability of fine coal. Final report

Description: The Mulled Coal process is a technology which has evolved from a line of investigations which began in the 1970`s. There was a major breakthrough in 1990, and since then, with significant support from DOE-PETC, the technology has progressed from the conceptual stage to a proven laboratory process. It is a simple process which involves the addition of a low cost specifically formulated reagent to wet fine coal by mixing the two in a pug mill. Although the converted material (Mulled Coal) retains some of its original surface moisture, it handles, transports, and stores like dry coal. But, unlike thermally dried fine coal Mulled Coal is not dusty, it will not rewet, and it causes no fugitive dust problems. This project was designed to advance the technology from the status of a process which works well in the laboratory to the status of a technology which is fully ready for commercialization. Project objectives were to: 1. Prove the concept that the technology can be used to produce Mulled Coal of a consistent quality, on a continuous basis, at a convincing rate of production, and at a major preparation plant which produces fine clean coal on a commercial basis. 2. Prove the concept that Mulled Coal, either as a blend with coarser clean coal or as a stand-alone fuel will successfully pass through a representative cross section of conventional coal storage, handling and transportation environments without causing any of the problems normally associated with wet fine coal. 3 Test the design and reliability of Mulled Coal circuit equipment and controls. 4. Test the circuit over a wide range of operating conditions. 5. Project scale-up designs for major equipment components and control circuits. 6. Forecast capital and operating costs for commercial circuits ranging from 25 TPH to 75 TPH. This report describes ...
Date: March 1, 1996
Creator: Maxwell, R.C. Jr. & Jamison, P.R.
Partner: UNT Libraries Government Documents Department

POC-SCALE TESTING OF OIL AGGLOMERATION TECHNIQUES AND EQUIPMENT FOR FINE COAL PROCESSING

Description: This report covers the technical progress achieved from July 01, 1997 to September 30, 1997 on the POC-Scale Testing Agglomeration Techniques and Equipment for Fine Coal Processing project. Experimental procedures and test data for recovery of fine coal from coal fines streams generated at a commercial coal preparation plant are described. Two coal fines streams, namely Sieve Bend Effluent and Cyclone Overflow were investigated. The test results showed that ash was reduced by more than 50% at combustible matter recovery levels exceeding 95%.
Date: January 1, 1998
Partner: UNT Libraries Government Documents Department

Advanced physical coal cleaning to comply with potential air toxic regulations. Quarterly report, 1 March 1995--31 May 1995

Description: Studies have indicated that the potentially hazardous trace elements found in coal have a strong affinity for coal pyrite. Thus, by maximizing the rejection of pyrite, one can minimize the trace element content of a given coal while also reducing sulfur emissions. The pyrite in most Illinois Basin coals, however, is finely disseminated within the coal matrix. Therefore, to remove the pyrite using physical coal cleaning techniques, the pyrite must be liberated by grinding the coal to ultrafine particle sizes. Fortunately, the coals being fed to pulverized coal boilers (PCB) are already ground to a very fine size, i.e., 70% passing 200 mesh. Therefore, this research project will investigate the use of advanced fine coal cleaning technologies for cleaning PCB feed as a compliance strategy. Work in this quarter has focused on the processing of a run-of-mine coal sample collected from Amax Coal Company`s Delta Coal mine using column flotation and an enhanced gravity separator as separate units and in circuitry arrangements. The {minus}60 mesh run-of-mine sample having an ash content of about 22% was cleaned to 6% while achieving a very high energy recovery of about 87% and a sulfur rejection value of 53% in a single stage column flotation operation. Enhanced gravity treatment is believed to be providing excellent total sulfur rejection values, although with inferior ash rejection for the {minus}400 mesh size fraction. The circuitry arrangement with the Falcon concentrator as the primary cleaner followed by the Packed-Column resulted in an excellent ash rejection performance, which out performed the release analysis. Trace element analyses of the samples collected from these tests will be conducted during the next report period.
Date: December 31, 1995
Creator: Honaker, R.Q.; Paul, B.C.; Mohanty, M.K. & Wang, D.
Partner: UNT Libraries Government Documents Department

A study of multistage/multifunction column for fine particle separation. Quarterly technical progress report, January 1, 1996-- March 31, 1996

Description: The overall objective of the proposed research program is to explore the potential application of a new invention involving a multistage column equipped with vortex-inducing loop-flow contactors (hereafter referred to as the multistage column) for fine coal cleaning process. The research work will identify the design parameters and their effects on the performance of the separation process. The results of this study will provide an engineering basis for further development of this technology in coal cleaning and in the general areas of fluid/particle separation. In the last quarter, we investigated the mixing and loop flow (circulation) behaviors around the contactors. In this quarter, the fine coal beneficiation tests were carried out in the multistage column and conventional column.
Date: April 20, 1996
Creator: Chiang, Shiao-Hung
Partner: UNT Libraries Government Documents Department

Improvement of storage, handling, and transportability of fine coal. Quarterly technical progress report No. 4, October 1, 1994--December 31, 1994

Description: The objectives of this project are to demonstrate that: The Mulled Coal process, which has been proven to work on a wide range of wet fine coals at bench scale, will work equally well on a continuous basis, producing consistent quality at a convincing rate of production in a commercial coal preparation plant. The wet product from a fine coal cleaning circuit can be converted to a solid fuel form for ease of handling and cost savings in storage and rail car transportation. A wet fine coal product thus converted to a solid fuel form, can be stored, shipped, and burned with conventional fuel handling, transportation, and combustion systems. During this fourth quarter of the contract period, activities were underway under Tasks 2 and 3. Sufficient characterization of the bench-scale testing and pilot-plant testing results enabled the design and procurement activities to move forward. On that basis, activities in the areas of design and procurement that had been initiated during the previous quarter were conducted and completed.
Date: August 20, 1996
Partner: UNT Libraries Government Documents Department

Improvement of storage, handling, and transportability of fine coal. Quarterly technical progress report No. 7, July 1, 1995--September 30, 1995

Description: The Mulled Coal process was developed as a means of overcoming the adverse handling characteristics of wet fine coal without thermal drying. The process involves the addition of a low cost harmless reagent to wet fine coal using off-the-shelf mixing equipment. Based on laboratory- and bench-scale testing, Mulled Coal can be stored, shipped, and burned without causing any of the plugging, pasting, carryback and freezing problems normally associated with wet coal. The objectives of this project are to demonstrate that: The Mulled Coal process, which has been proven to work on a wide range of wet fine coals at bench scale, will work equally well in a commercial coal preparation plant. The wet product from a fine coal cleaning circuit can be converted to a solid fuel form for ease of handling and cost savings in storage and rail car transportation. A wet fine coal product thus converted to a solid fuel form can be stored, shipped, and burned with conventional fuel handling, transportation, and combustion systems. The Mulled Coal circuit was installed in an empty bay at the Chetopa Preparation Plant. Equipment has been installed to divert a 2.7 tonnes/hr (3 tons/hr) slipstream of the froth concentrate to a dewatering centrifuge. The concentrated wet coal fines from the centrifuge dropped through a chute directly into a surge hopper and feed system for the Mulled Coal circuit. The Mulled Coal product was gravity discharged from the circuit to a truck or product discharge area from which it will be hauled to a stockpile located at the edge of the clean coal stockpile area. During the 3-month operating period, the facility produced 870 tonnes (966 tons) of the Muffed Coal for evaluation in various storage, handling, and transportation equipment and operations. Immediately following the production demonstration, the circuit was disassembled and ...
Date: August 22, 1996
Partner: UNT Libraries Government Documents Department

Improvement of storage, handling, and transportability of fine coal. Quarterly technical progress report No. 5, January 1, 1995--March 31, 1995

Description: The Mulled Coal process was developed as a means of overcoming the adverse handling characteristics of wet fine coal without thermal drying. The process involves the addition of a low cost, harmless reagent to wet fine coal using off-the-shelf mixing equipment. Based on laboratory- and bench-scale testing, Mulled Coal can be stored, shipped, and burned without causing any of the plugging, pasting, carryback and freezing problems normally associated with wet coal. The objectives of this project are to demonstrate that: the Mulled Coal process, which has been proven to work on a wide range of wet fine coals at bench scale, will work equally well on a continuous basis, producing consistent quality at a convincing rate of production in a commercial coal preparation plant; the wet product from a fine coal cleaning circuit can be converted to a solid fuel form for ease of handling and cost savings in storage and rail car transportation; and a wet fine coal product thus converted to a solid fuel form, can be stored, shipped, and burned with conventional fuel handling, transportation, and combustion systems. During this reporting period, virtually all of the technical activities and progress was made in the areas of circuit installation and startup operations. Work in these activity areas are described.
Date: August 21, 1996
Partner: UNT Libraries Government Documents Department

A study of multistage/multifunction column for fine particle seperation

Description: The objective if this program is to explore the potential application of a multistage column equipped with concentric draft- tubes (multistage column) for fine coal cleaning. The aim is to identify design parameters of the separation process. In the last quarter we conducted the gas holdup measurement which is an essential part of the hydrodynamic experiments for establishing a process model for engineering design and scale-up.
Date: September 7, 1997
Creator: Chiang, S.
Partner: UNT Libraries Government Documents Department

Fine coal fractionation using a magnetohydrostatic separation process CRADA 91-003. Final report

Description: The magnetohydrostatic separation (MHS) process uses a magnetic fluid which has the ability to float a submerged particle in a magnetic field. The objective of this project was to develop a technique for laboratory gravity fractionation of coal using MHS.
Date: October 31, 1992
Creator: Cho, Heechan & Killmeyer, R.P.
Partner: UNT Libraries Government Documents Department

Engineering Development of Advanced Physical Fine Coal Cleaning for Premium Fuel Applications: Task 9 - Selective agglomeration Module Testing and Evaluation.

Description: The primary goal of this project was the engineering development of two advanced physical fine coal cleaning processes, column flotation and selective agglomeration, for premium fuel applications. The project scope included laboratory research and bench-scale testing of both processes on six coals to optimize the processes, followed by the design, construction, and operation of a 2 t/hr process development unit (PDU). The project began in October, 1992, and is scheduled for completion by September 1997. This report summarizes the findings of all the selective agglomeration (SA) test work performed with emphasis on the results of the PDU SA Module testing. Two light hydrocarbons, heptane and pentane, were tested as agglomerants in the laboratory research program which investigated two reactor design concepts: a conventional two-stage agglomeration circuit and a unitized reactor that combined the high- and low-shear operations in one vessel. The results were used to design and build a 25 lb/hr bench-scale unit with two-stage agglomeration. The unit also included a steam stripping and condensation circuit for recovery and recycle of heptane. It was tested on six coals to determine the optimum grind and other process conditions that resulted in the recovery of about 99% of the energy while producing low ash (1-2 lb/MBtu) products. The fineness of the grind was the most important variable with the D80 (80% passing size) varying in the 12 to 68 micron range. All the clean coals could be formulated into coal-water-slurry-fuels with acceptable properties. The bench-scale results were used for the conceptual and detailed design of the PDU SA Module which was integrated with the existing grinding and dewatering circuits. The PDU was operated for about 9 months. During the first three months, the shakedown testing was performed to fine tune the operation and control of various equipment. This was followed by parametric ...
Date: September 29, 1997
Creator: Moro, N. & Jha, M. C.
Partner: UNT Libraries Government Documents Department

Combustion characterization of coal-water slurry fuel

Description: As a result of coal cleaning operations, a substantial amount of coal is disposed as waste into the ponds, effecting and endangering the environment. This study includes a technique to recover and utilize the waste coal fines from the preparation plant effluent streams and tailing ponds. Due to the large moisture content of the recovered coal fines, this investigation is focused on the utilization of coal fines in the coal-water slurry fuel. It is our belief that a blend of plant coal and waste coal fines can be used to produce a coal-water slurry fuel with the desired combustion characteristics required by the industry. The coal blend is composed of 85% clean coal and 15% recovered coal fines. The coal-water slurry is prepared at 60% solids with a viscosity less than 500 centipose and 80-90% of solid particles passing through 200 mesh. This paper contains analysis of clean coal, recovered coal fines, and coal-water slurry fuel as well as combustion characteristics.
Date: December 31, 1996
Creator: Masudi, Houshang & Samudrala, S.
Partner: UNT Libraries Government Documents Department

Hydrophobic Dewatering of Fine Coal. Topical report, March 1, 1995-March 31, 1997

Description: Many advanced fine coal cleaning technologies have been developed in recent years under the auspices of the U.S. Department of Energy. However, they are not as widely deployed in industry as originally anticipated. An important reason for this problem is that the cleaned coal product is difficult to dewater because of the large surface area associated with fine particles. Typically, mechanical dewatering, such as vacuum filtration and centrifugation, can reduce the moisture to 20-35% level, while thermal drying is costly. To address this important industrial problem, Virginia Tech has developed a novel dewatering process, in which water is displaced from the surface of fine particulate materials by liquid butane. Since the process is driven by the hydrophobic interaction between coal and liquid butane, it was referred to as hydrophobic dewatering (HD). A fine coal sample with 21.4 pm median size was subjected to a series of bench-scale HD tests. It was a mid-vol bituminous coal obtained from the Microcel flotation columns operating at the Middle Fork coal preparation plant, Virginia. All of the test results showed that the HD process can reduce the moisture to substantially less than 10%. The process is sensitive to the amount of liquid butane used in the process relative to the solids concentration in the feed stream. Neither the intensity nor the time of agitation is critical for the process. Also, the process does not require long time for phase separation. Under optimal operating conditions, the moisture of the fine coal can be reduced to 1% by weight of coal.
Date: December 31, 1997
Creator: Yoon, R.; Sohn, S.; Luttrell, J. & Phillips, D.
Partner: UNT Libraries Government Documents Department

An Advanced Control System for Fine Coal Flotation. Sixth quarter, technical progress report, July 1-September 30, 1997

Description: Over the past thirty years, process control has spread from the chemical industry into the fields of mineral and coal processing. Today, process control computers, combined with improved instrumentation, are capable of effective control in many modem flotation circuits. Unfortunately, the classical methods used in most control strategies have severe limitations when used in froth flotation. For example, the nonlinear nature of the flotation process can cause single-input, single-output lines to battle each other in attempts to achieve a given objective. Other problems experienced in classical control schemes include noisy signals from sensors and the inability to measure certain process variables. For example, factors related to ore type or water chemistry, such as liberation, froth stability, and floatability, cannot be measured by conventional means. The purpose of this project is to demonstrate an advanced control system for fine coal flotation. The demonstration is being carried out at an existing coal preparation plant by a team consisting of Virginia Polytechnic Institute and State University (VPI&SU) as the prime contractor and J.A. Herbst and Associates as a subcontractor. The objectives of this work are: (1) to identify through sampling, analysis, and simulation those variables which can be manipulated to maintain grades, recoveries, and throughput rates at levels set by management; (2) to develop and implement a model-based computer control strategy that continuously adjusts those variables to maximize revenue subject to various metallurgical, economic, and environmental constraints; and (3) to employ a video-based optical analyzer for on-line analysis of ash content in fine coal slurries.
Date: October 27, 1997
Creator: Adel, G. T. & Luttrell, G. H.
Partner: UNT Libraries Government Documents Department

Combustion Characterization of Coal Fines Recovered from the Handling Plant

Description: Data obtained during combustion tests were analyzed for residence time, loss on ignition and carbon conversion efficiency. The residence time data revealed that, as the firing rate decreased the residence time increased. This can be attributed to the increase in the feed rate. The loss on ignition data at three different locations for each firing rate, revealed that the highest percentage of fuel, about 85 percent is burnt during residence time of 0.6 seconds, bottom location. The carbon conversion efficiency were computed from unburned carbon in ash for three firing rates at three different swirl settings. The highest carbon conversion efficiency was found to be 99.58 percent for the firing rate of 669,488 Btu/hr.
Date: April 1, 1996
Creator: Hasudi, H.; Samudrala, S.R.; Chenevert, L. & Tata, K.
Partner: UNT Libraries Government Documents Department

POC-scale testing of an advanced fine coal dewatering equipment/technique

Description: Froth flotation technique is an effective and efficient process for recovering of ultra-fine (minus 74 pm) clean coal. Economical dewatering of an ultra-fine clean-coal product to a 20% level moisture will be an important step in successful implementation of the advanced cleaning processes. This project is a step in the Department of Energy`s program to show that ultra-clean coal could be effectively dewatered to 20% or lower moisture using either conventional or advanced dewatering techniques. The cost-sharing contract effort is for 36 months beginning September 30, 1994. This report discusses technical progress made during the quarter from July 1 - September 30, 1997.
Date: September 1, 1998
Partner: UNT Libraries Government Documents Department

POC-SCALE TESTING OF AN ADVANCED FINE COAL DEWATERING EQUIPMENT/TECHNIQUE

Description: The main objective of the proposed program is to evaluate a novel surface modification technique, which utilizes the synergistic effect of metal ions-surfactant combination, for dewatering of ultra-fine clean coal on a proof-of-concept scale of 1 to 2 tph. The novel surface modification technique developed at the UKCAER will be evaluated using vacuum, centrifuge, and hyperbaric filtration equipment. Dewatering tests will be conducted using the fine clean-coal froth produced by the column flotation units at the Powell Mountain Coal Company, Mayflower Preparation Plant in St. Charles, Virginia. The POC-scale studies will be conducted on two different types of clean coal, namely, high-sulfur and low-sulfur clean coal. The Mayflower Plant processes coals from five different seams, thus the dewatering studies results could be generalized for most of the bituminous coals.
Date: February 3, 1998
Creator: PAREKH, B.K.; TAO, D. & GROPPO, J.G.
Partner: UNT Libraries Government Documents Department