Manoj K. Mohanty

Performance Optimization of the FGX Dry Separator for Cleaning High-Sulfur Coal

The main goal of the present study was not only to deshale (remove pure rock) raw coal extracted from Illinois mines but also to assess the maximum ash separation efficiency and sulfur rejection achievable using the FGX Dry Separator for cleaning raw coals of varying cleaning characteristics. A Model FGX-1 Dry Separator with feed throughput capacity of 10 tph was extensively tested at the Illinois Coal Development Park using multiple coal samples having distinctly different cleaning characteristics. Statistically designed experimental programs were conducted to indentify critical process variables and to optimize FGX Dry Separator performance by systematic adjustments of critical process variable parameters. The coal-cleaning performance of the FGX Dry Separator was evaluated for the particle size range of 4.75–63.5 mm in most cases, although FGX Dry Separator feed consisted of nominal 7minus;63.5 mm run-of-mine coals. Deck vibration frequency, longitudinal deck angle, feeder frequency, and baffle plate height were identified as critical process variables for the FGX Dry Separator. The best cleaning performance obtained from the FGX Dry Separator was described by specific gravity of separation (SG50) and probable error (Ep) values of 1.98 and 0.17, respectively. For a relatively easy-to-clean coal (having a Cleaning Index of 0.72), only about 0.42% of the clean coal (i.e., 1.6 float fraction) present in the feed was lost to the tailings stream. For a relatively difficult-to-clean coal (having a Cleaning Index of 0.53), about 0.98% of the clean coal present in the feed was lost to the tailings stream. The positive impact of having fine materials in the FGX feed stream was also noted in this study. A modified log-logistic partition model was developed using experimental data reported in literature and validated using new experimental data generated in this study. The results showed that this model could be effectively used to predict the FGX Dry Separator coal-cleaning performance.

Bioelectrochemical treatment of acid mine drainage (AMD) from an abandoned coal mine under aerobic condition

In this study, a bioelectrochemical system (BES) was used to treat acid mine drainage (AMD) from an abandoned coal mine in the cathode chamber under aerobic condition. Activated sludge from a local wastewater treatment plant was used in the anode chamber of the BES to supply electrons to the treatment. After 7days, the pH of the cathode solution enhanced from 2.5 to 7.3. More than 99% of Al, Fe and Pb were removed, and removal rates of 93%, 91%, 89% and 69% were achieved for Cd, Zn, Mn and Co respectively with biocathode. Energy-dispersive X-ray spectroscopy (EDS) study revealed the deposition of the various types of metals on the cathode surface, and some metals were detected in the precipitates of the cathode chamber. The bacteria for AMD treatment was identified to be Serratia spp. using 16s rRNA gene amplification and sequencing. Scanning electron microscopy showed attached growth of the bacteria on the cathode. The bioelectrochemical treatment of the AMD was also compared with the biological treatment in a continuously stirred batch reactor (CSBR).

Evaluation of a New Fine Coal Cleaning Circuit Consisting of a Stack Sizer and a Falcon Enhanced Gravity Concentrator

A single-deck full-scale Stack Sizer in conjunction with a Falcon Concentrator having a feed handling capacity up to 5 tph was used to demonstrate a new fine coal cleaning circuit especially for high-sulfur coal in this study. The experimental program was conducted to treat a slip stream from the feed to the raw coal cyclones operating in a coal preparation plant in the Midwestern United States. High-efficiency size separation achieved is described by an imperfection value of 0.21 and ultrafine bypass of 4.72% at a d50c of 77 micron. A reasonably low 1.74 specific gravity of separation was achieved by the Falcon Concentrator along with a probable error (Ep) value of 0.13 for cleaning nominally 1-mm × 75-micron coal. For a hypothetical fine coal cleaning circuit treating 100 tph of raw coal, the estimated total cost per ton of feed coal for the traditional fine coal cleaning circuit and the proposed new circuit are

Performance Optimization of a Coal Preparation Plant Using Genetic Algorithms

4.93 and

Techno-Economic Analysis of Coal Preparation Plant Design Using Siu-Sim Simulator

5.89, respectively. However, the authors believe that the significant reduction in sulfur penalty due to better pyrite rejection achievable with the proposed circuit may offset the higher cost of cleaning high-sulfur coal.

Optimization of the dewatering performance of a Steel belt filter

A coal preparation plant typically has multiple cleaning circuits based on size of coal particles. The traditional way of optimizing the plant output and meeting the product constraints such as ash, sulfur and moisture content is to equalize the average product quality from each circuit. The present study includes multiple incremental product quality approach to optimize the clean coal recovery while satisfying the product constraints. The plant output was optimized at the given constraints of 7.5% ash and 1.3% sulfur. It was observed that utilizing incremental product quality process gives 2.13% higher yield which can generate additional revenue of

A Theoretical Approach to Coal Flotation Washability Correlation

4,260,000 per annum than that obtained by using the equal average product quality approach in this particular case. This paper introduces a novel approach for optimizing plant output using Genetic Algorithms (GA) while satisfying the multiple quality constraints. The same plant product constraints were used for GA based analysis. The results showed that using GA as an optimization process gives 2.23% higher yield that will result in additional revenue generation of

Improving Fine Coal Cleaning Performance by High-Efficiency Particle Size Classification

4,460,000 per annum than average product quality approach. The GA serves as an alternative process to optimize the coal processing plant yield with multiple quality constraints.Copyright

Development and Demonstration of an Automation and Control System for Coal Spirals

A new coal preparation plant simulator has been developed to select the most profitable cleaning circuit-configuration based on a comprehensive techno-economic analysis of the feed coal characteristics, equipment performance, capital and operating costs, depreciation, taxes, and net present value (NPV). The resulting flowsheet not only gives the maximum clean coal yield while simultaneously satisfying the product quality and quantity constraints but also generates the maximum revenue within the plant life. The simulator also identifies the optimum operating conditions for individual cleaning circuits. Two sets of feed washability data were used to demonstrate the various features and utilizations of the new simulator. For each set of washability data, maximum yield, after-installation capital cost, operating cost, cost per ton of clean coal, cost per ton of raw coal, and NPV were calculated for the flowsheet used in the plant. The results were compared with the real-life plant operations with respect to product yield, ash content, sulfur content, heating value, and moisture content. The solutions were also compared with those obtained by the constant incremental product ash approach.

STEEL BELT FILTER: A SUITABLE TECHNOLOGY FOR DEWATERING FINE CLEAN COAL AND TAILINGS

The main goal of this study was to investigate the suitability of a newly developed fine particle dewatering technology, known as steel belt filter (SBF), for dewatering fine clean coal. The unique feature of this new technology is the combined use of both vacuum (suction force) and pressure (mechanical squeeze) for achieving the desired solid-liquid separation. A continuously operating SBF prototype unit having a belt width of 0.6 m was tested at the Illinois Coal Development Park. A factorial experimental design using the response surface methodology was conducted to optimize the dewatering performance of the SBF prototype unit. The clean coal slurry sample used as the dewatering feed was a combined spiral and flotation product with a mean particle size of 400 micron and an ash content of 19.2%. A solid recovery of greater than 99% was achieved by using a small dosage of an anionic flocculant. The minimum surface moisture content achieved by SBF dewatering was nearly 18.5%, whereas the mass product throughput capacity was 0.92 ton per hour (t/h) for a 0.6 wide SBF.