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05620 Dense medium cyclone separation of fine particles part 2. The effect of medium composition on dense medium cyclone performance
01
Solid fuels (preparation)
95105607 Studlrs of reduction and reductlvo alkylation of coals In the potassium/llquld ammonla system. 1. The Influence of demlnrrallzatlon on the course of reduction and rrductlvr alkylatlon of coals Wachowska, H. and Kozlowski, M. Fuel Seu. 1995, 74, (9). 1319-1327. Five Polish coals of different rank were sttbjecicd to the reactions of reduction and reductive alkylation in the system potassiumfliquid ammonia. The influence of demineralization on the course of these processes as well as on the amount and kind of the reaction oroducts was analvsed. Formation of a certain amount of impurities contaming mainly alky&mmonium iodides was detected during reductive alkylation. Reductive butylation was found to be more effective than reductive ethylation, which is determined mainly by the energy of dissociation of the iodine-alkyl group bond in the applied alkvlation agents. A relationshiu between the kind of substituents introduced into &al and solubility of the reaction products in methylene chloride and n-pentane is discussed. 95105606 Studles of reduction and rrductlve alkylatlon of coals In the potasslum/llquld ammonla system. 2. Characterlzatlon of coal extracts Wachowska, H. and Kozlowski, M. Fuel, Sep. 1995, 74, (9), 1328-1332. The products of reduction and reductive alkylation of five demineralized coals run in a system of potassium/Iiquid ammonia were subject to extraction of methylene chloride and n-pentane. The paper reports infrared and nuclear magnetic resonance (n.m.r.) characteristtcs of the extracts and the results of their elemental analysis and molecular weight determination. Analysis of n.m.r. spectra of the extracts permitted- determination of changes in their structural parameters from which inference is drawn about chemical transformation occurring in coals upon reduction and reductive alkylation. 95105609 A systematic neutron actlvatlon analysis of peat from Burundi Ntahokaja, W. and Zikovsky, L. J. Radioanal. Nucl. Chem., 1995, 199, (6), 431-441. The mean concentrations of a number of elements, and trace elements in Burundi peat were determined by neutron activation analysis. The peat of Burundi contained approximately the same concentrations of elements as the peats in other countries, but is enriched in Br and depleted in Ca, K, Mn. Sr. and Yb. 95l65616 Thermal analysis of anthracites, meta-anthracites, and graphltes Amarskii, E. G. and Vyalov, V. I. Khim. Tverd. Topl. (Moscow), 1995, (2), 89-95. (In Russian) A number of regionally metamorphosed anthracites and meta-anthracites and graphites, which were formed-by contact metamorphism of coal, were studied bv DTG and DTA. Reports that it is possible to differentiate these two groups by thermal analysis and to- determine their formation temperatures.
951056i 6 Comparlson of costs for dlfferrnt levels of coal cleaning for coal preparation plants In Poland Blaschke, W. et al., Coal Preparation, 1995, 16, (l), 103-114. The choice of preparation technology depends on different factors, resulting in different preparation costs. In order to determine the dependence of the preparation costs upon the complexity of cleaning technology, preparation plants are classified by complexity of preparation (technological models). In Poland. nrenaration olants can be classified into four tvoes. For two chosen preparation’plants, which are representatives of diffe&t technological models, the costs of cleaning different coal sizes are presented. The calculation for the aalyzed variants were carried out based on discounted costs in order to unify the method of calculation. The principles, methodology and the results of the calculations are the subject of the paper.
95lQ5617 Conslderatlons based on the mathematical model for the optlmal control of the coal dresslng by jlgglng %13;;la.A. L. and Tiberiu, V. Modell. Meas. Control C, 1995, 48, (4), Describes a modelling study of coal washing. The aim of the study is a mathematical model which takes into account the stratification pattern of the material in the process.
95105616 Coprocesslng of coal/bitumen and hydrogen donor ability of coal Sasaki, M. and Yoshida, T. Nippon Enerugi Gahkaishi, 1995, 74, (S), 288-295. (In Japanese) Discusses the hydrogen donating properties of coal, the relation between hydrogen donatmg property and chemical structure of coal, and hydrogen transfer in coprocessing.
95105619 Dense medium cyclone separation of flno partlclss Part 1. The effect of medlum split ratio on dense medium cyclone performance He, Y. B. and Laskowski, J. S. Coal Preparation, 1995, 16, (l), l-25. Among dense medium cyclone operating variables, the medium split ratio is identified as the fundamental operating variable. It is most directly related to dense medium cyclone performance; other operatin variables influence the dense medium cyclone performance by changing ta e medium split ratio. At medium split ratios below one, the separation efficiency deteriorates drastically due to the short-circuitin of the feed. Increasing the medium split ratio improves the separation ef p!. rctency. At medium split ratios above 4.0. the imurovement in dense medium cvclone oerformance is insignificant, ‘while the adverse effects of plugging ‘and roping become more pronounced. The cutpoint shift also increases with the medium split ratio. It is recommended that the medium split ratio be close to the overflow to underflow product ratio.
Preparation 95105611 The analysis of the dynamic regime of a coal concentration process Susana,A. Modell. Meas. Control C, 1995, 50, (2), 47-49. Describes a modelling study of coal washing. 95lO5612 Apparatus for drying and grading coal with hot air Sato, T. et al., (Assigned to) Shinnippon Seitetsu KK JAP. Pat. JP.O7,11,270, Jan. 1995. 95105613 Change In the properties of brown-coal brlquets wlth addltlon of hydrolytic llgnln durlng storage Saranchuk, V. I. et al., Khim. Tverd. Topl. (Moscow), 1995, (l), 25-29. (In Russian) Discusses the minimal changes in briquettes quality during storage for br:rrxtes containing 20% lignin. The briquettes can be stored for up to 6 95tO5614 Characterlzatlon of the Ca-Fe-S-W-0 system as a final product of hlgh temperature coal brlquet sulfur capture Lin, G. et al., Huanjing Kexue, 1994, 15, (3) 15-17. (In Chinese) The ash from burning a coal brtquette with a Si or Fe additive to capture sulphur was characterized by X-ray powder diffraction and X-ray fluorescent specrometry, giving the same chemical composition as that derived from elemental analysis data. 95165615 Coal condltlonlng process Winterhoff, M. A. (Assigned to) Chemical Dewatering Technology Inc.,
US Pat. 5,402,894, Apr. 1995. The process is used for improving the efficiency of coal dewaterina and
deashing using complexing ageniS such as sod&m luconate in alkaline solution to form soluble comoounds with cations sue 6 as Al”. Fe”. Mn”. and Ca**.The formation of these compounds reduces the adsorption’an$or desorbs clay slimes from the surface of coal.
464
Fuel and Energy Abstracts November 1995
95165620 Dense medium cyclone separation of fine particles Part 2. The effect of medium composltlon on dense medium cyclone performance He, Y. B. and Laskowski, J. S. Coal Preparation, 1995, 16, (l), 27-49. The effect of medium composition on dense medium cyclone performance is investigated. It is found that a change in composition affects medium stability and rheology, and may lead to different responses in separation efficiencv and cutooint shift. The final result deoends on whether the medium itability 0; rheology is the dominant facto;, and also on the feed particle size. An ideal medium composition is found to be one with a biomodal particle size distribution. Such a medium exhibits low viscosity and improved stability. Optimum dense medium cyclone performance is achieved with the magnetite dense medium characterized by a biomodal particle size distribution when the medium contains approximately 25% fine and 75% coarse magnetite.
95165621 Differential adhesion of hydrophobic bacteria onto coal and associated minerals Raichur,A. M. et al., Coal Preparation, 1995, 16, (1) 51-63. The selective adhesion of hydrophobic Mycobacterium phlei to coal particles is responsible for flocculation of fine coal from its associated ash formin minerals. The driving force for the differential adhesion is the hydropRobic interactions between the surface of the organism through its constituents such as fatty acids and coal particles. The effect of Mycobacterium phlei on surface hydrophobicity, surface charge and mechanism of adhesion on coal and associated minerals are controlled by several factors including hydrophobicity and surface and solution chemistry of the system. Adhesion measurements indicate that maximum adhesion occurs below the iso-electric point (IEP) of the coal particles. While massive adhesion of Mycobacteriumphlei is observed on coal, only negligible amount of Mycobacterium phlei attached to pyrite and quartz.
Solid fuels (preparation)
95105607 Studlrs of reduction and reductlvo alkylation of coals In the potassium/llquld ammonla system. 1. The Influence of demlnrrallzatlon on the course of reduction and rrductlvr alkylatlon of coals Wachowska, H. and Kozlowski, M. Fuel Seu. 1995, 74, (9). 1319-1327. Five Polish coals of different rank were sttbjecicd to the reactions of reduction and reductive alkylation in the system potassiumfliquid ammonia. The influence of demineralization on the course of these processes as well as on the amount and kind of the reaction oroducts was analvsed. Formation of a certain amount of impurities contaming mainly alky&mmonium iodides was detected during reductive alkylation. Reductive butylation was found to be more effective than reductive ethylation, which is determined mainly by the energy of dissociation of the iodine-alkyl group bond in the applied alkvlation agents. A relationshiu between the kind of substituents introduced into &al and solubility of the reaction products in methylene chloride and n-pentane is discussed. 95105606 Studles of reduction and rrductlve alkylatlon of coals In the potasslum/llquld ammonla system. 2. Characterlzatlon of coal extracts Wachowska, H. and Kozlowski, M. Fuel, Sep. 1995, 74, (9), 1328-1332. The products of reduction and reductive alkylation of five demineralized coals run in a system of potassium/Iiquid ammonia were subject to extraction of methylene chloride and n-pentane. The paper reports infrared and nuclear magnetic resonance (n.m.r.) characteristtcs of the extracts and the results of their elemental analysis and molecular weight determination. Analysis of n.m.r. spectra of the extracts permitted- determination of changes in their structural parameters from which inference is drawn about chemical transformation occurring in coals upon reduction and reductive alkylation. 95105609 A systematic neutron actlvatlon analysis of peat from Burundi Ntahokaja, W. and Zikovsky, L. J. Radioanal. Nucl. Chem., 1995, 199, (6), 431-441. The mean concentrations of a number of elements, and trace elements in Burundi peat were determined by neutron activation analysis. The peat of Burundi contained approximately the same concentrations of elements as the peats in other countries, but is enriched in Br and depleted in Ca, K, Mn. Sr. and Yb. 95l65616 Thermal analysis of anthracites, meta-anthracites, and graphltes Amarskii, E. G. and Vyalov, V. I. Khim. Tverd. Topl. (Moscow), 1995, (2), 89-95. (In Russian) A number of regionally metamorphosed anthracites and meta-anthracites and graphites, which were formed-by contact metamorphism of coal, were studied bv DTG and DTA. Reports that it is possible to differentiate these two groups by thermal analysis and to- determine their formation temperatures.
951056i 6 Comparlson of costs for dlfferrnt levels of coal cleaning for coal preparation plants In Poland Blaschke, W. et al., Coal Preparation, 1995, 16, (l), 103-114. The choice of preparation technology depends on different factors, resulting in different preparation costs. In order to determine the dependence of the preparation costs upon the complexity of cleaning technology, preparation plants are classified by complexity of preparation (technological models). In Poland. nrenaration olants can be classified into four tvoes. For two chosen preparation’plants, which are representatives of diffe&t technological models, the costs of cleaning different coal sizes are presented. The calculation for the aalyzed variants were carried out based on discounted costs in order to unify the method of calculation. The principles, methodology and the results of the calculations are the subject of the paper.
95lQ5617 Conslderatlons based on the mathematical model for the optlmal control of the coal dresslng by jlgglng %13;;la.A. L. and Tiberiu, V. Modell. Meas. Control C, 1995, 48, (4), Describes a modelling study of coal washing. The aim of the study is a mathematical model which takes into account the stratification pattern of the material in the process.
95105616 Coprocesslng of coal/bitumen and hydrogen donor ability of coal Sasaki, M. and Yoshida, T. Nippon Enerugi Gahkaishi, 1995, 74, (S), 288-295. (In Japanese) Discusses the hydrogen donating properties of coal, the relation between hydrogen donatmg property and chemical structure of coal, and hydrogen transfer in coprocessing.
95105619 Dense medium cyclone separation of flno partlclss Part 1. The effect of medlum split ratio on dense medium cyclone performance He, Y. B. and Laskowski, J. S. Coal Preparation, 1995, 16, (l), l-25. Among dense medium cyclone operating variables, the medium split ratio is identified as the fundamental operating variable. It is most directly related to dense medium cyclone performance; other operatin variables influence the dense medium cyclone performance by changing ta e medium split ratio. At medium split ratios below one, the separation efficiency deteriorates drastically due to the short-circuitin of the feed. Increasing the medium split ratio improves the separation ef p!. rctency. At medium split ratios above 4.0. the imurovement in dense medium cvclone oerformance is insignificant, ‘while the adverse effects of plugging ‘and roping become more pronounced. The cutpoint shift also increases with the medium split ratio. It is recommended that the medium split ratio be close to the overflow to underflow product ratio.
Preparation 95105611 The analysis of the dynamic regime of a coal concentration process Susana,A. Modell. Meas. Control C, 1995, 50, (2), 47-49. Describes a modelling study of coal washing. 95lO5612 Apparatus for drying and grading coal with hot air Sato, T. et al., (Assigned to) Shinnippon Seitetsu KK JAP. Pat. JP.O7,11,270, Jan. 1995. 95105613 Change In the properties of brown-coal brlquets wlth addltlon of hydrolytic llgnln durlng storage Saranchuk, V. I. et al., Khim. Tverd. Topl. (Moscow), 1995, (l), 25-29. (In Russian) Discusses the minimal changes in briquettes quality during storage for br:rrxtes containing 20% lignin. The briquettes can be stored for up to 6 95tO5614 Characterlzatlon of the Ca-Fe-S-W-0 system as a final product of hlgh temperature coal brlquet sulfur capture Lin, G. et al., Huanjing Kexue, 1994, 15, (3) 15-17. (In Chinese) The ash from burning a coal brtquette with a Si or Fe additive to capture sulphur was characterized by X-ray powder diffraction and X-ray fluorescent specrometry, giving the same chemical composition as that derived from elemental analysis data. 95165615 Coal condltlonlng process Winterhoff, M. A. (Assigned to) Chemical Dewatering Technology Inc.,
US Pat. 5,402,894, Apr. 1995. The process is used for improving the efficiency of coal dewaterina and
deashing using complexing ageniS such as sod&m luconate in alkaline solution to form soluble comoounds with cations sue 6 as Al”. Fe”. Mn”. and Ca**.The formation of these compounds reduces the adsorption’an$or desorbs clay slimes from the surface of coal.
464
Fuel and Energy Abstracts November 1995
95165620 Dense medium cyclone separation of fine particles Part 2. The effect of medium composltlon on dense medium cyclone performance He, Y. B. and Laskowski, J. S. Coal Preparation, 1995, 16, (l), 27-49. The effect of medium composition on dense medium cyclone performance is investigated. It is found that a change in composition affects medium stability and rheology, and may lead to different responses in separation efficiencv and cutooint shift. The final result deoends on whether the medium itability 0; rheology is the dominant facto;, and also on the feed particle size. An ideal medium composition is found to be one with a biomodal particle size distribution. Such a medium exhibits low viscosity and improved stability. Optimum dense medium cyclone performance is achieved with the magnetite dense medium characterized by a biomodal particle size distribution when the medium contains approximately 25% fine and 75% coarse magnetite.
95165621 Differential adhesion of hydrophobic bacteria onto coal and associated minerals Raichur,A. M. et al., Coal Preparation, 1995, 16, (1) 51-63. The selective adhesion of hydrophobic Mycobacterium phlei to coal particles is responsible for flocculation of fine coal from its associated ash formin minerals. The driving force for the differential adhesion is the hydropRobic interactions between the surface of the organism through its constituents such as fatty acids and coal particles. The effect of Mycobacterium phlei on surface hydrophobicity, surface charge and mechanism of adhesion on coal and associated minerals are controlled by several factors including hydrophobicity and surface and solution chemistry of the system. Adhesion measurements indicate that maximum adhesion occurs below the iso-electric point (IEP) of the coal particles. While massive adhesion of Mycobacteriumphlei is observed on coal, only negligible amount of Mycobacterium phlei attached to pyrite and quartz.