Browsing by Author "Kiesel, Richard F"
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Item Green Ball Characterization(University of Minnesota Duluth, 2005-09-13) Kiesel, Richard FThe objective of this research project was to correlate the physical quality of green balls with their behavior in the elastic region of the deformation curve under load. An understanding of the parameters that are key to the production of these quality standards will help to improve the quality of their products. Green ball quality is accepted by the industry as one of these key parameters. A procedure to further characterize green balls and develop a relationship to current quality assessment procedures will provide insight to the physical attributes and integrity of the green balls. A digital force gauge and compression test stand interlocked with PC based software was used to collect data and develop the relationship with the deformation of the green ball. Data on both wet and dried green balls were collected on varied bentonite additions and green ball moisture concentrations. The slope of the deformation curve, in the elastic region, was studied with regards to the green ball drop number, moisture content, wet strength and dry strength. The deformation behavior of the green balls is indirectly proportional to the slope of the deformation curve. As the elasticity of the green ball increases, the dry drop number, wet drop number and dry compressive strength is reduced. Although no significantly strong relationships are present, it is believed that the relationships to green ball quality, by collecting sufficient data over a period of time, can be significant.Item Influence of High Intensity Mixing on Green Ball and Fired Pellet Properties(University of Minnesota Duluth, 2011-11) Kiesel, Richard FFor the Minnesota Taconite Industry to compete in today’s global economy, pellet quality must meet or exceed the standards being set by its competitors. Green ball quality is accepted by the industry as one of the key parameters influencing fired pellet quality and bentonite binders have been established as the industry standard for North American mines. Previous studies have shown that the opportunity exists to use high intensive mixing of binder and concentrate to reduce additive rates and enhance quality. Historically these units were cost prohibitive for retrofit in the taconite operations, however the economic models have changed. The type of mixing intensity required and the parameters influenced must be identified to complete cost benefit models and properly size apparatuses for further economic consideration. The objective of this project is to compare the benefits of intensive mixing with typical standard mixing procedures using the physical and metallurgical quality of both green balls and fired pellets as guidelines.Item Iron Ore Green Ball Porosity Measurements(University of Minnesota Duluth, 2005-09-13) Kiesel, Richard FThe objective of this research project is to investigate the potential for mercury porosimetry to measure and characterize pore characteristics for iron ore green balls and fired pellets. Pellet porosity is significant to the diffusion of oxygen during the oxidation and reducing gases through fired pellets and therefore critical to both physical and metallurgical quality.Item Next Generation Metallic Iron Nodule Technology in Electric Arc Steelmaking – Phase II(University of Minnesota Duluth, 2010) Fosnacht, Donald R; Iwasaki, Iwao; Kiesel, Richard F; Englund, David J; Hendrickson, David W; Bleifuss, Rodney LItem Pellet Fines Removal System(University of Minnesota Duluth, 2005-09-13) Kiesel, Richard FThe primary objective of this research project was to test a portable, larger scale version of the prototype NRRI Fines Removal System, previously developed at the Coleraine Minerals Research Laboratory, at a fired pellet feed rate of 150-250 LTPH or higher at Minnesota Taconite operations.Item Use of Improved Densification Conditions for Producing High Fuel Content Products from Biomass Processed by Torrefaction, Hydrothermal Carbonization, and Various Densification Methodologies: Final Report(University of Minnesota Duluth, 2018-03-31) Fosnacht, Donald R; Hagen, Timothy S; Young, Matthew; Carden, Kendall; Kiesel, Richard FThe Natural Resources Research Institute is engaged in work to develop demonstration-level production of solid biofuel densified products that can be stored outside, have high bulk densities for ease of logistical transport, have good handling characteristics that minimize dust generation, possess grindability that is like coal used in power plants, and have fuel contents that match or exceed sub-bituminous coal levels. During the work, two pretreatment technologies have been investigated for concentrating the energy content of raw biomass. These include: torrefaction using an indirectly fired rotary kiln process at the demonstration level and hydrothermal carbonization at the bench and pilot scale. The Institute has also collaborated with Syngas technologies on a pilot-scale moving bed, directly heated steambased process at the pilot scale and next year will install this technology at the demonstration scale. A key factor in showing the full technical feasibility of using the pretreated materials is to demonstrate that the produced particulate fuel products can be densified to a level that allows good logistical and handling practices to be routinely attained. It has been found that hydrothermally carbonized processed materials can be agglomerated using a variety of densification devices including pelleting and briquetting in a repeatable and practical manner using commercial densification equipment with and without the use of binders. However, torrefied materials have proven to be much more difficult to densify using a variety of densification equipment, especially as the degree of torrefaction increases. Uniformly torrefied materials at high energy level appear to be especially difficult to densify but have the attributes of high fuel value and good grindability, with very little residual fiber content compared to less-torrefied material or steam-exploded biomass. Therefore, the work undertaken and explained in the following discussion has been conducted and shows that highly torrefied materials can be satisfactorily densified to produce high-energy-content products that have good physical properties, possess acceptable moisture resistance, low ash, sulfur and mercury content, and have bulk densities that can lead to improved logistics. The densification practices involve optimizing overall process conditions on an integrated systems basis and include moisture level, densification pressure, mix preparation pressure, and the use of appropriate binders when required. The densification system that seems to show the greatest promise for the highly torrefied materials is briquetting. Work will continue in examining other densification options and in improving the conditions used and discussed in this report.Item Use of Improved Densification Conditions for Producing High Fuel Content Products from Biomass Processed by Torrefaction, Hydrothermal Carbonization, and Various Densification Methodologies: Final Report(University of Minnesota Duluth, 2018-03-31) Fosnacht, Donald R; Hagen, Timothy S; Young, Matthew; Carden, Kendall; Kiesel, Richard FThe Natural Resources Research Institute is engaged in work to develop demonstration-level production of solid biofuel densified products that can be stored outside, have high bulk densities for ease of logistical transport, have good handling characteristics that minimize dust generation, possess grindability that is like coal used in power plants, and have fuel contents that match or exceed sub-bituminous coal levels. During the work, two pretreatment technologies have been investigated for concentrating the energy content of raw biomass. These include: torrefaction using an indirectly fired rotary kiln process at the demonstration level and hydrothermal carbonization at the bench and pilot scale. The Institute has also collaborated with Syngas technologies on a pilot-scale moving bed, directly heated steam-based process at the pilot scale and next year will install this technology at the demonstration scale. A key factor in showing the full technical feasibility of using the pretreated materials is to demonstrate that the produced particulate fuel products can be densified to a level that allows good logistical and handling practices to be routinely attained. It has been found that hydrothermally carbonized processed materials can be agglomerated using a variety of densification devices including pelleting and briquetting in a repeatable and practical manner using commercial densification equipment with and without the use of binders. However, torrefied materials have proven to be much more difficult to densify using a variety of densification equipment, especially as the degree of torrefaction increases. Uniformly torrefied materials at high energy level appear to be especially difficult to densify but have the attributes of high fuel value and good grindability, with very little residual fiber content compared to less-torrefied material or steam-exploded biomass. Therefore, the work undertaken and explained in the following discussion has been conducted and shows that highly torrefied materials can be satisfactorily densified to produce high-energy-content products that have good physical properties, possess acceptable moisture resistance, low ash, sulfur and mercury content, and have bulk densities that can lead to improved logistics. The densification practices involve optimizing overall process conditions on an integrated systems basis and include moisture level, densification pressure, mix preparation pressure, and the use of appropriate binders when required. The densification system that seems to show the greatest promise for the highly torrefied materials is briquetting. Work will continue in examining other densification options and in improving the conditions used and discussed in this report.