The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
L. Lin - One of the best experts on this subject based on the ideXlab platform.
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A novel dual-Screw coal Feeder for production of low sulfur fuel
1993Co-Authors: L. Lin, Soon-jai Khang, Tim C. KeenerAbstract:In this project, the following tasks have been performed: (1) Setting up the Dual-Screw Feeder reactor. (2) Determination of the pyrolysis product and the sulfur distribution in char, tar and gas based on experimental data. (3) Study of the devolatilization and the desulfurization kinetics and obtaining the basic kinetic parameters. (4) Study of the sulfur removal efficiency of lime pellets fed into the outer tube of the dual-Screw Feeder reactor. (5) Study of the effect of the coal particle size on pyrolysis and desulfurization. (6) Study of the coal pyrolysis using a TGA (Thermal Gravimetric Analyzer). (7) Study of the coal desulfurization using a tube oven. (8) Setting up a combustor. (9) Study of the combustion characteristics of the pyrolysis products from the dual-Screw Feeder reactor. (10) Process simulation of the dual-Screw Feeder reactor. The experimental results of devolatilization and desulfurization of an Ohio {number_sign}8 coal demonstrate that an increasing the temperature in mild coal pyrolysis leads to the increase of both the devolatilization yield and the desulfurization yield. Under the experimental conditions, mainly the organic sulfur releases in the form of H{sub 2}S. Both the devolatilization and the desulfurization processes can be described by using the first-order-reaction model whichmore » gives the activation energy values for pyrolysis and desulfurization of 170,021 kJ/mol and 78,783 kJ/mol, indicating the sulfur is easier to release than volatiles. The outer Screw region of CaO pellets also demonstrated almost a complete removal of hydrogen sulfide from volatiles. At a temperature of 475{degree}C and a residence time of 6 minutes, 73.1% of the organic sulfur was removed in the Screw Feeder reactor. The investigation of the combustion characteristics of the pyrolysis products showed a negligible reduction of the total heating value of the char and volatile products.« less
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A novel coal Feeder for production of low sulfur fuel. Quarterly technical progress report, October 1, 1992--January 1, 1993
1993Co-Authors: Soon-jai Khang, Tim C. Keener, L. LinAbstract:A dual-Screw Feeder was designed and constructed for desulfurization of coal. The Feeder consists mainly of two concentric Screw tubes, the inner tube acting as a coal pyrolyzer and the outer tube acting as a desulfurizer with hot calcined lime pellets or other renewable sorbent pellets. Two basic processes are involved in the development of this reactor: the mild pyrolysis of coal and the reaction of H{sub 2}S with calcium based sorbent. It combines the coal pyrolysis and the sulfur removal processes in one reactor. The objective of this project is to study the feasibility of an advanced concept of desulfurization inthe coal Feeder. In this quarter, the following tasks have been performed: (1) Measurement of volatile yield at different temperature by using TGA, (2) Elemental analysis of the char products from the pyrolysisprocess in the Screw Feeder, and (3) Improvement of the sampling system of the combustor. The following preliminary conclusions have been confirmed: (1) In the pyrolysis process, the volatile yield of Ohio No. 8 coal significantly increases between 300--500{degrees}C. (2) As devolatilization yield increases, desulfurization yield also increases. (3) The denitrification of Ohio No. 8 coal in the dual-Screw Feeder increases as the temperature and/or residence timemore » increases.« less
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A novel coal Feeder for production of low sulfur fuel. Quarterly technical process report, October 1, 1991--January 1, 1992
1991Co-Authors: L. Lin, S.j. Khang, Tim C. KeenerAbstract:In this project, a dual-Screw Feeder was designed for desulfurization of coal. The key parts of this reactor are two Screw tubes which are used to feed coal and calcined lime particles separately, the inner tube acting as a coal pyrolyzer and the outer tube acting as a desulfurizer with hot calcined lime pellets or other renewable sorbent pellets. The objective of this project is to study the feasibility of an advanced concept of desulfurization in the coal Feeder. (VC)
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A novel coal Feeder for production of low sulfur fuel. Quarterly technical progress report, December 1, 1989--April 1, 1990
1990Co-Authors: Soon-jai Khang, Tim C. Keener, L. LinAbstract:A dual-Screw Feeder was designed and tested for desulfurization of coal. The key parts of this reactor are two Screw tubes which independently feed coal and calcined lime, the inner tube acting as a coal pyrolizer and the outer tube acting as a desulfurizer with hot calcined lime pellets or other renewable sorbent pellets. The objective of this project is to study the feasibility of this advanced concept of desulfurization using the coal Feeder. In this quarter, the following tasks have been performed: (1) Analytical measurements of the organic sulfur content in the feed coal and the product char, (2) setting up the combustor which is physically attached to the Feeder system and will be used to study the combustion characteristics of char and volatiles produced from the pyrolysis process. The following preliminary conclusions have been obtained: (1) A 73.1% of the organic sulfur in Ohio {number_sign}8 coal was removed in the dual-Screw Feeder reactor at a temperature of 475{degrees}C with the residence time of 6 min. (2) The combustor works stably and the operating temperature of the combustor can be adjusted by controlling the char feed rate and the air flowrate. 2 tabs.
Justin Fernandez - One of the best experts on this subject based on the ideXlab platform.
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effect of Screw design on hopper drawdown of spherical particles in a horizontal Screw Feeder
Chemical Engineering Science, 2011Co-Authors: Paul W. Cleary, Justin Fernandez, William McbrideAbstract:Abstract Screw Feeders are used to remove material from hoppers and bins at a controlled rate. The evenness of the flow in the bin depends on the drawdown pattern, which in turn depends on the Screw and hopper design, shape of the particles and wall friction effects. A key design requirement is to ensure that a progressive increase in the Screws volumetric capacity is achieved along the entire length of the hopper's opening so as to produce even drawdown. If this is not achieved then compositional variations in the outgoing stream and other operational problems (such as caking) can be created. Screw designs to date have been generally based on analytical models and at times the predicted flow pattern is not achieved. In this study, the Discrete Element Method (DEM) is used to predict particle transport in a horizontal Screw Feeder system for a range of conventional Screw designs including a variable Screw pitch, variable Screw flight outside diameters and variable core diameters. The influence of Screw choice on the particle mass flow rate, the evenness of particle drawdown from the hopper, power consumption, Screw wear and wall friction variations are all investigated. Important features captured by DEM that are not accounted for by the analytic model and which vary strongly between competing Screw designs, include the particle circulation in the hopper, shearing of the particle bed in the trough just outside the Screw and the spatially varying particle force along the hopper which leads to non-uniform drawdown and to the existence of large stagnant or slow moving zones. The Screw design and consequent flow patterns also strongly affect the power draw with variations up to a factor of three and Screw wear with large changes in their distribution and magnitude. Finally, the surface frictional properties of the Screw are shown to strongly influence the rate of bed compaction within and along the Screw leading to strong variation in mass flow rate, uniformity of drawdown and power draw.
Jürgen Hesser - One of the best experts on this subject based on the ideXlab platform.
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Discrete element method (DEM) simulation and validation of a Screw Feeder system
Powder Technology, 2016Co-Authors: Daniela Kretz, S. Callau-monje, M. Hitschler, A. Hien, Matthias Raedle, Jürgen HesserAbstract:A computational particle flow simulation of a Feeder which transports bulk material through a horizontal cylinder by a turning Screw is presented. The objective is hereby the simulation-assisted support of system design. Such systems are used in industry to either create packages of material which have a very accurately determined mass or to produce a continuous flow of the used bulk material. The well known and common problems in practical applications are the missing stability of material flux over time, throughput changes with product quality drifts and a lack in design know how based on theoretical solutions. Therefore a simulation tool is realized by Blender software (v 2.68) to foster straight forward and goal oriented Screw and apparatus design. The geometrical and physical properties of the system are adjusted to a real Feeder system on which the experimental measurements are performed. Simulation parameters like wall friction, internal shear forces and angle of repose are fitted to the real experimental data. Absolute deviations are smaller than 8. %. We demonstrate that a simplified particle simulation tool is able to predict properties of a real machine that progresses bulk material with different types of Screws. The mass flow rate in simulation differs from the experimental mass flow rate less than 10. % for different Screw types and angular velocities of the Screw. Qualitative properties like the inflow and outflow behavior of the bulk are compared and the conformity is verified. It is shown that quite a simple particle simulation tool is able to verify and predict properties of a machine that progresses bulk material with different types of Screws. The simulation tool allows the modeling of all relevant machine parts without expensive real manufacturing and to test their characteristics.
Tim C. Keener - One of the best experts on this subject based on the ideXlab platform.
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A novel dual-Screw coal Feeder for production of low sulfur fuel
1993Co-Authors: L. Lin, Soon-jai Khang, Tim C. KeenerAbstract:In this project, the following tasks have been performed: (1) Setting up the Dual-Screw Feeder reactor. (2) Determination of the pyrolysis product and the sulfur distribution in char, tar and gas based on experimental data. (3) Study of the devolatilization and the desulfurization kinetics and obtaining the basic kinetic parameters. (4) Study of the sulfur removal efficiency of lime pellets fed into the outer tube of the dual-Screw Feeder reactor. (5) Study of the effect of the coal particle size on pyrolysis and desulfurization. (6) Study of the coal pyrolysis using a TGA (Thermal Gravimetric Analyzer). (7) Study of the coal desulfurization using a tube oven. (8) Setting up a combustor. (9) Study of the combustion characteristics of the pyrolysis products from the dual-Screw Feeder reactor. (10) Process simulation of the dual-Screw Feeder reactor. The experimental results of devolatilization and desulfurization of an Ohio {number_sign}8 coal demonstrate that an increasing the temperature in mild coal pyrolysis leads to the increase of both the devolatilization yield and the desulfurization yield. Under the experimental conditions, mainly the organic sulfur releases in the form of H{sub 2}S. Both the devolatilization and the desulfurization processes can be described by using the first-order-reaction model whichmore » gives the activation energy values for pyrolysis and desulfurization of 170,021 kJ/mol and 78,783 kJ/mol, indicating the sulfur is easier to release than volatiles. The outer Screw region of CaO pellets also demonstrated almost a complete removal of hydrogen sulfide from volatiles. At a temperature of 475{degree}C and a residence time of 6 minutes, 73.1% of the organic sulfur was removed in the Screw Feeder reactor. The investigation of the combustion characteristics of the pyrolysis products showed a negligible reduction of the total heating value of the char and volatile products.« less
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A novel coal Feeder for production of low sulfur fuel. Quarterly technical progress report, October 1, 1992--January 1, 1993
1993Co-Authors: Soon-jai Khang, Tim C. Keener, L. LinAbstract:A dual-Screw Feeder was designed and constructed for desulfurization of coal. The Feeder consists mainly of two concentric Screw tubes, the inner tube acting as a coal pyrolyzer and the outer tube acting as a desulfurizer with hot calcined lime pellets or other renewable sorbent pellets. Two basic processes are involved in the development of this reactor: the mild pyrolysis of coal and the reaction of H{sub 2}S with calcium based sorbent. It combines the coal pyrolysis and the sulfur removal processes in one reactor. The objective of this project is to study the feasibility of an advanced concept of desulfurization inthe coal Feeder. In this quarter, the following tasks have been performed: (1) Measurement of volatile yield at different temperature by using TGA, (2) Elemental analysis of the char products from the pyrolysisprocess in the Screw Feeder, and (3) Improvement of the sampling system of the combustor. The following preliminary conclusions have been confirmed: (1) In the pyrolysis process, the volatile yield of Ohio No. 8 coal significantly increases between 300--500{degrees}C. (2) As devolatilization yield increases, desulfurization yield also increases. (3) The denitrification of Ohio No. 8 coal in the dual-Screw Feeder increases as the temperature and/or residence timemore » increases.« less
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A novel coal Feeder for production of low sulfur fuel. Quarterly technical process report, October 1, 1991--January 1, 1992
1991Co-Authors: L. Lin, S.j. Khang, Tim C. KeenerAbstract:In this project, a dual-Screw Feeder was designed for desulfurization of coal. The key parts of this reactor are two Screw tubes which are used to feed coal and calcined lime particles separately, the inner tube acting as a coal pyrolyzer and the outer tube acting as a desulfurizer with hot calcined lime pellets or other renewable sorbent pellets. The objective of this project is to study the feasibility of an advanced concept of desulfurization in the coal Feeder. (VC)
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A novel coal Feeder for production of low sulfur fuel. Quarterly technical progress report, December 1, 1989--April 1, 1990
1990Co-Authors: Soon-jai Khang, Tim C. Keener, L. LinAbstract:A dual-Screw Feeder was designed and tested for desulfurization of coal. The key parts of this reactor are two Screw tubes which independently feed coal and calcined lime, the inner tube acting as a coal pyrolizer and the outer tube acting as a desulfurizer with hot calcined lime pellets or other renewable sorbent pellets. The objective of this project is to study the feasibility of this advanced concept of desulfurization using the coal Feeder. In this quarter, the following tasks have been performed: (1) Analytical measurements of the organic sulfur content in the feed coal and the product char, (2) setting up the combustor which is physically attached to the Feeder system and will be used to study the combustion characteristics of char and volatiles produced from the pyrolysis process. The following preliminary conclusions have been obtained: (1) A 73.1% of the organic sulfur in Ohio {number_sign}8 coal was removed in the dual-Screw Feeder reactor at a temperature of 475{degrees}C with the residence time of 6 min. (2) The combustor works stably and the operating temperature of the combustor can be adjusted by controlling the char feed rate and the air flowrate. 2 tabs.
William Mcbride - One of the best experts on this subject based on the ideXlab platform.
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effect of Screw design on hopper drawdown of spherical particles in a horizontal Screw Feeder
Chemical Engineering Science, 2011Co-Authors: Paul W. Cleary, Justin Fernandez, William McbrideAbstract:Abstract Screw Feeders are used to remove material from hoppers and bins at a controlled rate. The evenness of the flow in the bin depends on the drawdown pattern, which in turn depends on the Screw and hopper design, shape of the particles and wall friction effects. A key design requirement is to ensure that a progressive increase in the Screws volumetric capacity is achieved along the entire length of the hopper's opening so as to produce even drawdown. If this is not achieved then compositional variations in the outgoing stream and other operational problems (such as caking) can be created. Screw designs to date have been generally based on analytical models and at times the predicted flow pattern is not achieved. In this study, the Discrete Element Method (DEM) is used to predict particle transport in a horizontal Screw Feeder system for a range of conventional Screw designs including a variable Screw pitch, variable Screw flight outside diameters and variable core diameters. The influence of Screw choice on the particle mass flow rate, the evenness of particle drawdown from the hopper, power consumption, Screw wear and wall friction variations are all investigated. Important features captured by DEM that are not accounted for by the analytic model and which vary strongly between competing Screw designs, include the particle circulation in the hopper, shearing of the particle bed in the trough just outside the Screw and the spatially varying particle force along the hopper which leads to non-uniform drawdown and to the existence of large stagnant or slow moving zones. The Screw design and consequent flow patterns also strongly affect the power draw with variations up to a factor of three and Screw wear with large changes in their distribution and magnitude. Finally, the surface frictional properties of the Screw are shown to strongly influence the rate of bed compaction within and along the Screw leading to strong variation in mass flow rate, uniformity of drawdown and power draw.
