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02612 Swelling of a German brown coal in acetone-water and methanol-water mixtures
01
Solid fuels (preparation)
Role of carboxyl groups in the disintegration 97lO2598 brown coal briquettes by water sorption
of
Ozaki. J.-i. CI nl. Fuel Protuc,. Techrrol.. 1997, 50. (I). 57-6X. By means of water sorption on model briquettes made from acid-washed, and heat-treated coals, the cation-exchanged. water vapour-conditioned. role of carboxyl groups in the disintegration of hrown coal briquettes was investigated. Cracks were observed on the surfaces of briquettes with initial sorption rates of >0.06 g-H20/g coal-minimum The results from acidwashed and cation-exchanged coals revealed that the carboxylate cations act as hydration sites to promote the disintegration. whereas carboxyl groups act as hydrogen bonding sites to prevent it. A negative correlation between r,,,, and the amount of carboxyl groups present demonstrated the effectiveness of carboxyl groups in preventing the disintegration. Heattreated coals showed a rapid decrease in r,“, up to 2OO”C, in which there is no significant change in the carhoxyl group content. This was explained in terms of swelling suppression.
97/02599 products
Scanning electron microscopy analysis from different comminution methods
of coal
Zhu, Q. et al. Fluidlfnr?. Sep. J.. 1996, 9, (3). 181-184. Products resulting from the comminution of four coals possessing different hardness, sulfur content, and mineral-matter distribution were analysed in this study. Physical property analyses and mineral liberation studies were conducted. The physical properties were studied using a scanning electron microscope (SEM) and SEM-IPS image analysis system. Mineral matter, pyrite. and carbonaceous material were identified, and the area fraction of each was determined from the backscattered electron images. The shape difference of coal particles from various comminution processes are described using a circular shape factor. The paper analyses the results of these laboratory studies.
97102600 tion plants
Screen dewatering
of coal-clay
waste from prepara-
Schemer. B. J. Coal Prep., lY96, 17, (l-2), 39-46. The author presents a flocculation-screening technique to dewater coal-clay waste, developed by the Bureau of Mines at Tuscaloosa Research Center. The technique involves flocculation of the waste stream with polyethylene oxide and dewatering of the resulting floes on a static screen. Test results are described from pilot plant and field testing of four different wastes. Coal dewatering is also discussed in general, with the effect of particle size on dewatering efficiency.
Separation
97102601 flotation
of coal particles
from Soma fly ash by
Bayat, 0. and Toraman, 0. Y. Changing Scopes Miner. Process., Proc. Int. Miner. f’mcess. Symp., 6th. 1996, 469-473. Edited by Kemal, M. B.. Rotterdam, Neth. Fly ash flotation from the Soma Power Plant gave a 65.06%burnable unburned carbon fraction with 37.56% ash at pH 6.0, 30’C and 6.24 lit concentration of kerosene + pine oil. The consumption of the reagents was comparatively high in all experiments and the process economy for operation on a technical scale may be unsatisfactory. Experiments should therefore be carried out using various reagent types to improve the process economy.
97102602 structure
Solid state 13C CPIMAS-study after rapid heating
Kawashima. H. et al. Japanese). Changes in coal structure NMR after heat-treatment flow. The author suggests and THFS with heating plasticity.
Shigen
fo
Kar~kyo,
1996,
of changes 5,
(6),
in coal
397-402.
(In
of Akabira coal were examined by solid state 13C at 3 Kimin or 100 Kimin at 723 K under nitrogen that the increase witnessed in molecular mobility rate may have been due to enhanced thermal
Solubilization of an Australian brown coal oxidized 97102603 with hydrogen peroxide in conventionally used solvents at room temperature Mae, K. et rrl. Prepr. Pap. Am. Chem. SW., Div. Fuel Chem.. 1997, 42, (1). 176-l 80. The oxidization of an Australian brown coal took place with hydrogen peroxide at 60°C for 2 h. Subsequently, extraction with alcohol-based binary solvents at room temperature was undertaken, to give a maximum extract yield of >80 wt7c.
97102604 ecologically
Status of foreign R&D clean coal technologies
programs
in the
area
of
Vyskubenko, Y. A. 1~1,.Akad. Nauk, Energ., 1996, (S), 1l-30 (In Russian) The current status of technlogical and R&D for decreased emissions from coal-fired power stations in the USA is evaluated. These include clean combustion, flue gas treatment, and coal treatment.
216
Fuel and Energy Abstracts
July 1997
97102605 Studies on the use of perchloroethylene medium for the removal of pyrites from coal
as a heavy
Theme. T. L. rf crl. Proc.-Annu. fnt. Pitfshurgh Cool Cm/:. IYYh, l3.(2). 1030-I 035. Perchloroethylene (PCE) has shown promise for USC as a heavy medium tor the removal of pyrites from fine coal. Mixtures of PCE and kerosene arc investigated here to determine their effectiveness for coal cleaning. Floati sink experiments are undertaken for different medium densities obtained by varying the proportions of PCE and kerosene. Data taken from a long tube sampling apparatus is used to evaluate the mixtures. The data support\ scale-up predictions for a plant apparatus. 97102606
Study on factors
affecting
microbial
solubilization
of lignite. Tong, W. ef al. Mcrtan Zhrrarrhr~~. 1996, 19, (3), 63-68. (In Chinese) Zalainuoer and Pingzhuang lignites were subjected to soluhization tests. carried out with Polyporus versicolor and Candida ML-13. The conversion of microbial soluhilization of lignites was shown to he affected by the incubation conditions, such as the component of incubation medium. the amount of inoculum, and solubilization methods.
97102607 Study thermogravimetry
on
multistage
hydropyrolysis
of coal
by
Li, W. and Li. B. Run&o Huuxue X~tehuo, IYYh. 24. (6). 480-4X4 (In Chinese) Xianfeng lignite. Datong bituminous coal and Yanzhou high sulfur coal were subjected to multi-stage hydropyrolysis and the results were investigated. The results show that the conversion of coal at high heating rate in multi-stage hydropyrolysis is higher than that at constantly~ slow heating rate. The multi-stage hydropyrolysis process is an ideal deaulfurization method for pro-combustion utilization. The sulfur removal of Yanzhou coal can reach 90%.
97102608 Supercritical mineral coal
fluid extraction
of a high-ash
Brazilian
Rocha, S. R. P. et ul. Process Tech&. Proc.. 1906. I2 (High Pressure Chemical Engtneering), 185%IYO. Experiments were carried out to determine the effects of extraction temperature, solvent density and addition of co-solvents on the conversion, liquid yield and the characteristics of the extracts and residues from SCFE with toluene of a high-ash Brazilian mineral coal. investigated. The experiments were performed in a semi-hatch. laboratory-scale unit at 593-673 K and up to 1 I5 MPa.
97102609 Surface changes in coals after oxidation. photoelectron spectroscopy studies
1. X-ray
Grzybek, T. and Kreiner, K. Langmuir, lY97, 13, (S) YOY-Yl2. The effect of liquid-phase oxidation on the surface structure of coal\ was studied by XPS. The surface composition changes. together with the content ratio of N/C, prove the applicability of the two-component model to describe the structure of coal. The mobile phase contains sulfur but no nitrogen compounds. Detailed discussion of the formation of oxygencontaining surface groups is facilitated by the analysis of the C( Is) peak shape.
97102610 Surface sorption studies
changes
in coals
after
oxidation.
2. Hz0
Grzyhek, T. et al. Langmuir. 1997, 13, (5), 1123-l 127. Quantitative characterization of the effects of oxidation on the surface of coal based on water sorption measurements were undertaken. Two coals of different rank were examined before and after oxidation with H202 and KMnO+ A theoretical model describing sorption equilibrium, as the effect of adsorption in submicropores and absorption in the elastic phase of coal. was applied to evaluate structural and energetic parameters of the sorption systems. A noticeable increase in the adsorption capacity of the studied coals followed oxidation and absorption was virtually unaffected by it. This is due to creation of new oxygen-containing surface groups on the coal surface, as was shown by XPS measurements. Results showed a significant increase in the adsorption energy, together with much smaller changes in water molecule concentration on the coal surface. This suggests an increase in the number of double bonds between adsorbed water molecules and oxygen-containing surface groups.
97102611 Surface improve dewatering
chemical
control
of
ultra-fine
coal
to
Groppo, J. G. and Parekh, B. K. Coul Prep. (Gor-don & Brmch), lYY6, 17, (l-2), 103-116. A combination of metal ions and surfactants were used in conventional vacuum filtration to lower the filter cake moisture of ultra-fine coal to 20%. The moisture reduction results from the formation of hydrophobic microaggregates which facilitates dewatering.
97102612 Swelling of a German and methanol-water mixtures
brown coal in acetone-water
Jones, J. C. er al. Fuel, 1997, 76, (7), 567-573. The coal swelling that arose when German brown coal samples were treated with acetone-water and methanol-water mixtures of different compositions was measured. These mixtures have higher solubility parameters than
01
binary organic solvent mixtures commonly used in such experiments. By matching coal and solvent solubility parameters swelling is maximized. The experiment takes note, however, of supplementary effects, including those accompanying the entry of solvent into the coal pores.
Thermal and catalytic coprocessing of Illinois No 6. coal with model and commingled waste plastics Luo, M. and Curtis. C. W. Fuel Process. Techno!., 1996, 49. (I-3). 91-l 17.
97102613
Under typical direct liquefaction reaction conditions, co-processing waste plastics with coal was investigated using slurry phase MO and Fe hydrogenation catalysts. Reactions were performed with individual model polymers, including polyisoprene, polystyrene, and high- and low-density polyethylene (HDPE, LDPE), and with coal alone in the presence and absence of a hydrogen donor solvent and catalysts at 400°C and 5.6 MPa initial Hz pressure. Polyisoprene and polystyrene liquefied readily under these conditions; however, neither HDPE nor LDPE liquefied much with these catalysts or conditions. Catalytic reactions using carbon black, minerals, and fluid catalytic cracking catalysts were performed with HDPE and LDPE to evaluate their effect on conversion. Co-processing reactions of LDPE and coal and commingled plastics and coal were subsequently performed with four fluid catalytic cracking catalysts and a zeolite HZSM-5. HZSM-5 was the most effective catalyst for converting both co-processing \yrtemu, although it produced more gaseous products than the tluid carnlvtic cracking catalysts. The co-processing reactions with commingled plastics and coal resulted in a lower conversion and less hexane-soluhle materials than the LDPE co-processing system.
Treatment
97102614
of coal before supplying
in coke oven
Yokomizo. M. et al. Jpn. Kokai Tokkyo Koho JP 09 31.470 [97 31.4701 (Cl. CIOBS7/10), 4 Feb 1997, Appl. 951177,420, 13 Jul 1995. h pp. (In Japanese) After drying, the coal is separated into coarse powder and fine powder in a process associated with the retention of the separation ratio by controlling water content in the dried coal measured at the output of drying apparatus. The fine powder is then mixed with an additive, kneaded, and blended with the coarse powder to give a product for charging into coke oven. Dust dispersion is prevented in this coal during carbonization.
97102615 separations
Use of a magnetic
fluid-based
process
for
coal
Fofana. M. and Klima. M. S. Miner. M&d/. Process., 1997, 14. (1). 35-40. The paper examines the use of a laboratory-scale magnetic fluid-based separator for coal separations. A Frantz laboratory magnetic separator was modified by fabricating new pole pieces of the appropriate geometry to provide the proper magnetic field gradients. Two Plexiglas separation chamhera were designed to fit between the pole pieces. A commercially available water-based ferromagnetic fluid was used as the separating medium and the separating density was changed by varying the current intensity of the electromagnet coil. Both hatch and continuous sepns. were made using 0.5’) x 0.50 mm and 0.18 x 0.15.mm coal. Good agreement was ohservcd between the washability results and those obtained from washing with organic liquids. The exception was the ash fraction with specific gravity 1.3, which was consistently higher in the magnetic fluid separation.
Transport,
Storage
Calculation of the air flow rate for ventilation of of underground storage bunkers A. I. ef al. Bezop. Tr. Promzti. 1996, (ll), 23-25. (In Russian)
Bohrov, Discusses coal mine ventilation.
97102617 Coal log pipeline design and economics Liu, H. BHR Group Conf. Ser. Pd., 1996, 20, (Slurry Handling and Pipeline Transport, Hydrotransport 13) 779-791. Coal in cylinder form is transported hydraulically through a pipe in a typical future commercial coal log pipeline (CLP) system. It consists of an inlet subsystem at a coal mine, a pipeline (including pumps and fittings), and an outlet suhsvstem located either at a large power plant or at an interchange for reloading the transported coal logs on a barge. train, truck, or conveyor belt. Information is given on the key elements of each sub-system, including design, operation, and economics. A comparison is made between the economics of CLP were and coal slurry pipeline, unit train, and truck. From this comparison, the market of CLP was established and described, and the advantages and state of development of CLP were discussed.
Factors
influencing
increased beyond that required to produce a stoichiometric volatiles-air mixture. The experimental results also showed that, as its particle size decreases, less rock dust is required to inert an explosion.
97102619
Fiber glass reinforced
plastic pipes for coal mines
Golyshkin, S. P. et al. (igol’ l/X-r.. 1996. (3), 39. (In Russian) Fibre glass reinforced plastic pipe construction for sprinkling, water pumping out, feeding compressed air, etc. for coal mines is detailed. The technical characteristics of the tube and butt joint are given.
97102620
Fire in a coal handling
plant
Lambrecht, V. VGB Kmftwerk~trch.. lY9h. 76. (12). 101)6-100X. (In German) An investigation into the causes of a fire in the coal handling unit of a power station. Measures with regard to early warning of fire and firefighting are proposed.
97102621 Improvement of transportability of raw coal ultramicro powders in metallurgical furnaces or combustion furnace Ono, R. et al. Jpn.. Kokai Tokkyo Koho JP 09 20,905 [97 20,905) (Cl. C2lB5/00), 21 Jan 1997, Appl. 95ilh9.821, 5 Jul lY95, IO pp. (In Japanese) Improvement of transportability of dry raw coal of average HGI (hardgrove grinding index) >30 is attained by adhering transportahilityimproving agents containing solid compounds with average particle diameter <5 m on the coal surfaces. The solid compounds may he selected from 0x0 acid salts, nitrides, silicides, and carbides of metals, and clay minerals. Operation of metallurgical furnaces. such as blast furnaces. and combustion furnaces using the agents are studled.
97102622 Influence of binder and wall lubrication on compacting coal logs for hydraulic transport Li, Y. et ul. Proc. Anm. Int. Pittsburgh Coal Conf., 1996. 13, (2), 840-845. Firstly, coal logs were compacted by adding different levels of hinder to a bituminous coal in a steel mould with or without wall lubrication. After ejecting from the mould, the coal logs were immersed in water under 500 psi pressure for one hour. Log expansion due to water absorption was measured. With increasing binder concentrations. the expansion reduced significantly. The coal logs were then circulated through a recirculating pipe, The abrasion or wear of the coal logs was determined by measuring the weight loss as a function of circulating cycles through the pipe. It was found to increase with decreasing hinder concentrations. In the second part of the study, the effects of lubricating mould surface using two different solid lubricants were evaluated in term5 of force transmission. friction force. and wear resistance. For binderless coal logs, wall lubrication using calcium stearate or molybdenum disulfide did not improve wear resistance. whereas when binder was used, wall lubrication using calcium stearate Increased the force transmission hut did not significantly improve the coal log quality significantly. The molybdenum disulfide, however, lubricated mould increased the force transmission as well as reduced the coal log wear.
97/02623 Joseph Conrad and the spontaneous of coal. Part 1 Walters, A. D. Coal Prep., 1996, 17, (3-3), 147-165
97102616 chambers
97102616 explosions
Solid fuels (transport, storage)
the suppression
of coal dust
Dastidar. A. G. el a/. Furl, 1997. 76, 7), hh3-h70. The influences of ignition energy, coal dust concentration and particle size of rock dust on suppression of coal dust explosions were examined. Laboratory-scale tests were undertaken in a Siwek 20 L spherIcal explosion chamber. When using high ignition energies, excessively high amounts of rock dust were required due to a phenomenon known as overdriving the explosion. Results showed that tests with an ignition source >S kJ may overestimate the amount of rock dust required to inert an explosion. The amount of rock dust required decreased as coal dust concentration
combustion
In the early part of his career in marine transportation, Joseph Conrad obtained considerable experience in the early part of his career in the marine transportation of coal. During this period in the late 19th century spontaneous combustion of coal at sea had hecome an cxtremcly serious problem. This paper discusses the theory and practical implications of coal self heating. and using analysiq data from the late 19th century and combining it with three modern predictive equations developed by Barve and Mahadevan (Indian Institute of Technology), Moxon and Richardson (BH-Australia). and Smith and Lazzara (US Bureau of Mines). demonstrates that the coal carried by the Palestine was extremely prone to self heating, further aggravated by the conditions of the voyage.
97102624 Joseph Conrad and the spontaneous of coal. Part 2 Walters, A. D. Coal Prep.. 1906, 17. (3-4). 167-183.
combustiori
Technical and historical comments have heen added to Conrad’s description of the development of spontaneous combustion in a coal cargo at sea and his knowledge of the parameters concerned with the self heating of coal are examined. The findings of the Singapore Court of Inquiry into the sinking are reviewed and placed in the context of the technical awareness of that time.
97102625 dimensional
Oxidation rates of coals spontaneous heating
as measured
from
one-
Chen, X. D. and Stott, J. B. Cnmh~lsricrn a& Flume. 1997. 100. (4). 57X5Xh. Several New Zealand coals were examined to study their oxidation rates for temperatures below 100°C Extensive oxygen analyses during one-dimensional spontaneous heating, using an adiabatic (2 m long) column filled with 1IO kg of crushed coal particles, yielded oxidation rate% Experimental technique and a variety of complications Ied to scatter in the kinetic plots. This work demonstrates the difficulty of relating adiabatic laboratory experiments to the spontaneous heating and ignition of pile5 of stored coal.
Fuel and Energy Abstracts
July 1997
217
Solid fuels (preparation)
Role of carboxyl groups in the disintegration 97lO2598 brown coal briquettes by water sorption
of
Ozaki. J.-i. CI nl. Fuel Protuc,. Techrrol.. 1997, 50. (I). 57-6X. By means of water sorption on model briquettes made from acid-washed, and heat-treated coals, the cation-exchanged. water vapour-conditioned. role of carboxyl groups in the disintegration of hrown coal briquettes was investigated. Cracks were observed on the surfaces of briquettes with initial sorption rates of >0.06 g-H20/g coal-minimum The results from acidwashed and cation-exchanged coals revealed that the carboxylate cations act as hydration sites to promote the disintegration. whereas carboxyl groups act as hydrogen bonding sites to prevent it. A negative correlation between r,,,, and the amount of carboxyl groups present demonstrated the effectiveness of carboxyl groups in preventing the disintegration. Heattreated coals showed a rapid decrease in r,“, up to 2OO”C, in which there is no significant change in the carhoxyl group content. This was explained in terms of swelling suppression.
97/02599 products
Scanning electron microscopy analysis from different comminution methods
of coal
Zhu, Q. et al. Fluidlfnr?. Sep. J.. 1996, 9, (3). 181-184. Products resulting from the comminution of four coals possessing different hardness, sulfur content, and mineral-matter distribution were analysed in this study. Physical property analyses and mineral liberation studies were conducted. The physical properties were studied using a scanning electron microscope (SEM) and SEM-IPS image analysis system. Mineral matter, pyrite. and carbonaceous material were identified, and the area fraction of each was determined from the backscattered electron images. The shape difference of coal particles from various comminution processes are described using a circular shape factor. The paper analyses the results of these laboratory studies.
97102600 tion plants
Screen dewatering
of coal-clay
waste from prepara-
Schemer. B. J. Coal Prep., lY96, 17, (l-2), 39-46. The author presents a flocculation-screening technique to dewater coal-clay waste, developed by the Bureau of Mines at Tuscaloosa Research Center. The technique involves flocculation of the waste stream with polyethylene oxide and dewatering of the resulting floes on a static screen. Test results are described from pilot plant and field testing of four different wastes. Coal dewatering is also discussed in general, with the effect of particle size on dewatering efficiency.
Separation
97102601 flotation
of coal particles
from Soma fly ash by
Bayat, 0. and Toraman, 0. Y. Changing Scopes Miner. Process., Proc. Int. Miner. f’mcess. Symp., 6th. 1996, 469-473. Edited by Kemal, M. B.. Rotterdam, Neth. Fly ash flotation from the Soma Power Plant gave a 65.06%burnable unburned carbon fraction with 37.56% ash at pH 6.0, 30’C and 6.24 lit concentration of kerosene + pine oil. The consumption of the reagents was comparatively high in all experiments and the process economy for operation on a technical scale may be unsatisfactory. Experiments should therefore be carried out using various reagent types to improve the process economy.
97102602 structure
Solid state 13C CPIMAS-study after rapid heating
Kawashima. H. et al. Japanese). Changes in coal structure NMR after heat-treatment flow. The author suggests and THFS with heating plasticity.
Shigen
fo
Kar~kyo,
1996,
of changes 5,
(6),
in coal
397-402.
(In
of Akabira coal were examined by solid state 13C at 3 Kimin or 100 Kimin at 723 K under nitrogen that the increase witnessed in molecular mobility rate may have been due to enhanced thermal
Solubilization of an Australian brown coal oxidized 97102603 with hydrogen peroxide in conventionally used solvents at room temperature Mae, K. et rrl. Prepr. Pap. Am. Chem. SW., Div. Fuel Chem.. 1997, 42, (1). 176-l 80. The oxidization of an Australian brown coal took place with hydrogen peroxide at 60°C for 2 h. Subsequently, extraction with alcohol-based binary solvents at room temperature was undertaken, to give a maximum extract yield of >80 wt7c.
97102604 ecologically
Status of foreign R&D clean coal technologies
programs
in the
area
of
Vyskubenko, Y. A. 1~1,.Akad. Nauk, Energ., 1996, (S), 1l-30 (In Russian) The current status of technlogical and R&D for decreased emissions from coal-fired power stations in the USA is evaluated. These include clean combustion, flue gas treatment, and coal treatment.
216
Fuel and Energy Abstracts
July 1997
97102605 Studies on the use of perchloroethylene medium for the removal of pyrites from coal
as a heavy
Theme. T. L. rf crl. Proc.-Annu. fnt. Pitfshurgh Cool Cm/:. IYYh, l3.(2). 1030-I 035. Perchloroethylene (PCE) has shown promise for USC as a heavy medium tor the removal of pyrites from fine coal. Mixtures of PCE and kerosene arc investigated here to determine their effectiveness for coal cleaning. Floati sink experiments are undertaken for different medium densities obtained by varying the proportions of PCE and kerosene. Data taken from a long tube sampling apparatus is used to evaluate the mixtures. The data support\ scale-up predictions for a plant apparatus. 97102606
Study on factors
affecting
microbial
solubilization
of lignite. Tong, W. ef al. Mcrtan Zhrrarrhr~~. 1996, 19, (3), 63-68. (In Chinese) Zalainuoer and Pingzhuang lignites were subjected to soluhization tests. carried out with Polyporus versicolor and Candida ML-13. The conversion of microbial soluhilization of lignites was shown to he affected by the incubation conditions, such as the component of incubation medium. the amount of inoculum, and solubilization methods.
97102607 Study thermogravimetry
on
multistage
hydropyrolysis
of coal
by
Li, W. and Li. B. Run&o Huuxue X~tehuo, IYYh. 24. (6). 480-4X4 (In Chinese) Xianfeng lignite. Datong bituminous coal and Yanzhou high sulfur coal were subjected to multi-stage hydropyrolysis and the results were investigated. The results show that the conversion of coal at high heating rate in multi-stage hydropyrolysis is higher than that at constantly~ slow heating rate. The multi-stage hydropyrolysis process is an ideal deaulfurization method for pro-combustion utilization. The sulfur removal of Yanzhou coal can reach 90%.
97102608 Supercritical mineral coal
fluid extraction
of a high-ash
Brazilian
Rocha, S. R. P. et ul. Process Tech&. Proc.. 1906. I2 (High Pressure Chemical Engtneering), 185%IYO. Experiments were carried out to determine the effects of extraction temperature, solvent density and addition of co-solvents on the conversion, liquid yield and the characteristics of the extracts and residues from SCFE with toluene of a high-ash Brazilian mineral coal. investigated. The experiments were performed in a semi-hatch. laboratory-scale unit at 593-673 K and up to 1 I5 MPa.
97102609 Surface changes in coals after oxidation. photoelectron spectroscopy studies
1. X-ray
Grzybek, T. and Kreiner, K. Langmuir, lY97, 13, (S) YOY-Yl2. The effect of liquid-phase oxidation on the surface structure of coal\ was studied by XPS. The surface composition changes. together with the content ratio of N/C, prove the applicability of the two-component model to describe the structure of coal. The mobile phase contains sulfur but no nitrogen compounds. Detailed discussion of the formation of oxygencontaining surface groups is facilitated by the analysis of the C( Is) peak shape.
97102610 Surface sorption studies
changes
in coals
after
oxidation.
2. Hz0
Grzyhek, T. et al. Langmuir. 1997, 13, (5), 1123-l 127. Quantitative characterization of the effects of oxidation on the surface of coal based on water sorption measurements were undertaken. Two coals of different rank were examined before and after oxidation with H202 and KMnO+ A theoretical model describing sorption equilibrium, as the effect of adsorption in submicropores and absorption in the elastic phase of coal. was applied to evaluate structural and energetic parameters of the sorption systems. A noticeable increase in the adsorption capacity of the studied coals followed oxidation and absorption was virtually unaffected by it. This is due to creation of new oxygen-containing surface groups on the coal surface, as was shown by XPS measurements. Results showed a significant increase in the adsorption energy, together with much smaller changes in water molecule concentration on the coal surface. This suggests an increase in the number of double bonds between adsorbed water molecules and oxygen-containing surface groups.
97102611 Surface improve dewatering
chemical
control
of
ultra-fine
coal
to
Groppo, J. G. and Parekh, B. K. Coul Prep. (Gor-don & Brmch), lYY6, 17, (l-2), 103-116. A combination of metal ions and surfactants were used in conventional vacuum filtration to lower the filter cake moisture of ultra-fine coal to 20%. The moisture reduction results from the formation of hydrophobic microaggregates which facilitates dewatering.
97102612 Swelling of a German and methanol-water mixtures
brown coal in acetone-water
Jones, J. C. er al. Fuel, 1997, 76, (7), 567-573. The coal swelling that arose when German brown coal samples were treated with acetone-water and methanol-water mixtures of different compositions was measured. These mixtures have higher solubility parameters than
01
binary organic solvent mixtures commonly used in such experiments. By matching coal and solvent solubility parameters swelling is maximized. The experiment takes note, however, of supplementary effects, including those accompanying the entry of solvent into the coal pores.
Thermal and catalytic coprocessing of Illinois No 6. coal with model and commingled waste plastics Luo, M. and Curtis. C. W. Fuel Process. Techno!., 1996, 49. (I-3). 91-l 17.
97102613
Under typical direct liquefaction reaction conditions, co-processing waste plastics with coal was investigated using slurry phase MO and Fe hydrogenation catalysts. Reactions were performed with individual model polymers, including polyisoprene, polystyrene, and high- and low-density polyethylene (HDPE, LDPE), and with coal alone in the presence and absence of a hydrogen donor solvent and catalysts at 400°C and 5.6 MPa initial Hz pressure. Polyisoprene and polystyrene liquefied readily under these conditions; however, neither HDPE nor LDPE liquefied much with these catalysts or conditions. Catalytic reactions using carbon black, minerals, and fluid catalytic cracking catalysts were performed with HDPE and LDPE to evaluate their effect on conversion. Co-processing reactions of LDPE and coal and commingled plastics and coal were subsequently performed with four fluid catalytic cracking catalysts and a zeolite HZSM-5. HZSM-5 was the most effective catalyst for converting both co-processing \yrtemu, although it produced more gaseous products than the tluid carnlvtic cracking catalysts. The co-processing reactions with commingled plastics and coal resulted in a lower conversion and less hexane-soluhle materials than the LDPE co-processing system.
Treatment
97102614
of coal before supplying
in coke oven
Yokomizo. M. et al. Jpn. Kokai Tokkyo Koho JP 09 31.470 [97 31.4701 (Cl. CIOBS7/10), 4 Feb 1997, Appl. 951177,420, 13 Jul 1995. h pp. (In Japanese) After drying, the coal is separated into coarse powder and fine powder in a process associated with the retention of the separation ratio by controlling water content in the dried coal measured at the output of drying apparatus. The fine powder is then mixed with an additive, kneaded, and blended with the coarse powder to give a product for charging into coke oven. Dust dispersion is prevented in this coal during carbonization.
97102615 separations
Use of a magnetic
fluid-based
process
for
coal
Fofana. M. and Klima. M. S. Miner. M&d/. Process., 1997, 14. (1). 35-40. The paper examines the use of a laboratory-scale magnetic fluid-based separator for coal separations. A Frantz laboratory magnetic separator was modified by fabricating new pole pieces of the appropriate geometry to provide the proper magnetic field gradients. Two Plexiglas separation chamhera were designed to fit between the pole pieces. A commercially available water-based ferromagnetic fluid was used as the separating medium and the separating density was changed by varying the current intensity of the electromagnet coil. Both hatch and continuous sepns. were made using 0.5’) x 0.50 mm and 0.18 x 0.15.mm coal. Good agreement was ohservcd between the washability results and those obtained from washing with organic liquids. The exception was the ash fraction with specific gravity 1.3, which was consistently higher in the magnetic fluid separation.
Transport,
Storage
Calculation of the air flow rate for ventilation of of underground storage bunkers A. I. ef al. Bezop. Tr. Promzti. 1996, (ll), 23-25. (In Russian)
Bohrov, Discusses coal mine ventilation.
97102617 Coal log pipeline design and economics Liu, H. BHR Group Conf. Ser. Pd., 1996, 20, (Slurry Handling and Pipeline Transport, Hydrotransport 13) 779-791. Coal in cylinder form is transported hydraulically through a pipe in a typical future commercial coal log pipeline (CLP) system. It consists of an inlet subsystem at a coal mine, a pipeline (including pumps and fittings), and an outlet suhsvstem located either at a large power plant or at an interchange for reloading the transported coal logs on a barge. train, truck, or conveyor belt. Information is given on the key elements of each sub-system, including design, operation, and economics. A comparison is made between the economics of CLP were and coal slurry pipeline, unit train, and truck. From this comparison, the market of CLP was established and described, and the advantages and state of development of CLP were discussed.
Factors
influencing
increased beyond that required to produce a stoichiometric volatiles-air mixture. The experimental results also showed that, as its particle size decreases, less rock dust is required to inert an explosion.
97102619
Fiber glass reinforced
plastic pipes for coal mines
Golyshkin, S. P. et al. (igol’ l/X-r.. 1996. (3), 39. (In Russian) Fibre glass reinforced plastic pipe construction for sprinkling, water pumping out, feeding compressed air, etc. for coal mines is detailed. The technical characteristics of the tube and butt joint are given.
97102620
Fire in a coal handling
plant
Lambrecht, V. VGB Kmftwerk~trch.. lY9h. 76. (12). 101)6-100X. (In German) An investigation into the causes of a fire in the coal handling unit of a power station. Measures with regard to early warning of fire and firefighting are proposed.
97102621 Improvement of transportability of raw coal ultramicro powders in metallurgical furnaces or combustion furnace Ono, R. et al. Jpn.. Kokai Tokkyo Koho JP 09 20,905 [97 20,905) (Cl. C2lB5/00), 21 Jan 1997, Appl. 95ilh9.821, 5 Jul lY95, IO pp. (In Japanese) Improvement of transportability of dry raw coal of average HGI (hardgrove grinding index) >30 is attained by adhering transportahilityimproving agents containing solid compounds with average particle diameter <5 m on the coal surfaces. The solid compounds may he selected from 0x0 acid salts, nitrides, silicides, and carbides of metals, and clay minerals. Operation of metallurgical furnaces. such as blast furnaces. and combustion furnaces using the agents are studled.
97102622 Influence of binder and wall lubrication on compacting coal logs for hydraulic transport Li, Y. et ul. Proc. Anm. Int. Pittsburgh Coal Conf., 1996. 13, (2), 840-845. Firstly, coal logs were compacted by adding different levels of hinder to a bituminous coal in a steel mould with or without wall lubrication. After ejecting from the mould, the coal logs were immersed in water under 500 psi pressure for one hour. Log expansion due to water absorption was measured. With increasing binder concentrations. the expansion reduced significantly. The coal logs were then circulated through a recirculating pipe, The abrasion or wear of the coal logs was determined by measuring the weight loss as a function of circulating cycles through the pipe. It was found to increase with decreasing hinder concentrations. In the second part of the study, the effects of lubricating mould surface using two different solid lubricants were evaluated in term5 of force transmission. friction force. and wear resistance. For binderless coal logs, wall lubrication using calcium stearate or molybdenum disulfide did not improve wear resistance. whereas when binder was used, wall lubrication using calcium stearate Increased the force transmission hut did not significantly improve the coal log quality significantly. The molybdenum disulfide, however, lubricated mould increased the force transmission as well as reduced the coal log wear.
97/02623 Joseph Conrad and the spontaneous of coal. Part 1 Walters, A. D. Coal Prep., 1996, 17, (3-3), 147-165
97102616 chambers
97102616 explosions
Solid fuels (transport, storage)
the suppression
of coal dust
Dastidar. A. G. el a/. Furl, 1997. 76, 7), hh3-h70. The influences of ignition energy, coal dust concentration and particle size of rock dust on suppression of coal dust explosions were examined. Laboratory-scale tests were undertaken in a Siwek 20 L spherIcal explosion chamber. When using high ignition energies, excessively high amounts of rock dust were required due to a phenomenon known as overdriving the explosion. Results showed that tests with an ignition source >S kJ may overestimate the amount of rock dust required to inert an explosion. The amount of rock dust required decreased as coal dust concentration
combustion
In the early part of his career in marine transportation, Joseph Conrad obtained considerable experience in the early part of his career in the marine transportation of coal. During this period in the late 19th century spontaneous combustion of coal at sea had hecome an cxtremcly serious problem. This paper discusses the theory and practical implications of coal self heating. and using analysiq data from the late 19th century and combining it with three modern predictive equations developed by Barve and Mahadevan (Indian Institute of Technology), Moxon and Richardson (BH-Australia). and Smith and Lazzara (US Bureau of Mines). demonstrates that the coal carried by the Palestine was extremely prone to self heating, further aggravated by the conditions of the voyage.
97102624 Joseph Conrad and the spontaneous of coal. Part 2 Walters, A. D. Coal Prep.. 1906, 17. (3-4). 167-183.
combustiori
Technical and historical comments have heen added to Conrad’s description of the development of spontaneous combustion in a coal cargo at sea and his knowledge of the parameters concerned with the self heating of coal are examined. The findings of the Singapore Court of Inquiry into the sinking are reviewed and placed in the context of the technical awareness of that time.
97102625 dimensional
Oxidation rates of coals spontaneous heating
as measured
from
one-
Chen, X. D. and Stott, J. B. Cnmh~lsricrn a& Flume. 1997. 100. (4). 57X5Xh. Several New Zealand coals were examined to study their oxidation rates for temperatures below 100°C Extensive oxygen analyses during one-dimensional spontaneous heating, using an adiabatic (2 m long) column filled with 1IO kg of crushed coal particles, yielded oxidation rate% Experimental technique and a variety of complications Ied to scatter in the kinetic plots. This work demonstrates the difficulty of relating adiabatic laboratory experiments to the spontaneous heating and ignition of pile5 of stored coal.
Fuel and Energy Abstracts
July 1997
217