A mineralogical study of the Harmon lignite bed, Bullion Creek Formation (Paleocene), Bowman County, North Dakota

Study of the Harmon lignite bed at the Gascoyne Mine in Bowman County, North Dakota showed that most of the minerals in the coal lithobodies were detrital in origin and that variable ash deposition during combustion may be caused by variations in types and quantities of mineral phases. The Harmon bed is part of the Bullion Creek Formation (Paleocene). Objectives of this study included: to develop scanning electron microscope/microprobe techniques for the study of minerals in coal; to determine the origins of the mineral phases; to postulate a depositional environment for the Harmon lignite; and to ascertain whether variable ash deposition behavior of the Gascoyne lignite is related to mineral content. Scanning electron microscopy and electron microprobe analysis was used to identify and determine the abundance of minerals in the lignite. The average mineral content in weight percent was 44% quartz, 31% illite, 13% kaolinite, 5% montmorillonite, 5% pyrite, and 2% gypsum. The amount of mineral matter as discrete phases, not organically bound inorganic constituents, varied directly with total ash. The Blue Pit has a higher inorganic content than the White Pit because of a greater amount of quartz and clays in the B seam. This result demonstrates the lateral variability in inorganic content in the Gascoyne lignite. Minerals also varied in vertical distribution. Quartz and clay minerals were more abundant in lithologic layers that were adjacent to clay silt partings, overburden, and underclay. Quartz, illite, and kaolinite are primarily detrital in origin. Framboidal pyrite and possibly some kaolinite and phosphate minerals formed authigenically during early peat stages. Massive pyrite, gypsum, barite, celestite, siderite, and jarosite were probably epigenetic products which formed after seam compaction and coalification. The present mineral content of the Harmon lignite is probably the result of the characteristics of the depositional environment. Authigenic processes during early peat stages or after compaction and coalification had a minor influence on the current mineral content. The Harmon lignite was probably deposited as part of a lacustrine depositional environment. Periodic transgression and regression of the freshwater body would explain best the types of minerals observed and their distributions. Variations in ash deposition behavior within the Gascoyne Mine may be caused by the variation in types and quantities of discrete mineral phases

Advanced SEM Techniques to Characterize Coal Minerals

Research at the University of North Dakota Energy and Environmental Research Center (EERC) has focused on methods to characterize the inorganic components in coals. Because the scanning electron microscope and electron probe microanalysis system (SEM/EPMA) provide both morphologic and chemical information, the SEM/EPMA system is well-suited to the characterization of discrete minerals in coal. Computer-controlled scanning electron microscopy (CCSEM), along with simultaneous automated digital image collection, is one means of gaining more detailed insight into coal mineralogy. Computer-stored images of coal surfaces already analyzed for minerals using CCSEM can be reanalyzed to discern mineral morphologies and coal-to-mineral associations. Limitations may exist when using just CCSEM to characterize chemically and physically complex clay minerals without complimentary data on the association of the minerals to the coal organic matrix. Mineralogic investigations of San Miguel and Beulah lignites and Upper Freeport bituminous coal using CCSEM and automated digital image collection are given with a particular reference to the clay minerals present. Total mineral quantities generated for the three coals were in good agreement with total ash content, provided that organically bound constituents were taken into account for the lignites. Classification of the more complex aluminosilicate minerals was aided by the use of distribution plots of Si/Al ratios and concentrations of ion exchangeable cations derived from the CCSEM analysis. Morphologic analysis of stored SEM images proved to be helpful in characterizing kaolinite group minerals

VALIDATION OF FIRESIDE PERFORMANCE INDICES: FOULING/CORROSION EVALUATION OF MDF PARTICLEBOARD AND BLENDS WITH WHEAT STRAW BOARD

Sauder Woodworking currently fires a large portion of all wood wastes in a boiler producing process steam. It is investigating using particleboard made from wheat straw in its manufacturing process and is concerned with the effects of the inorganics on its boiler. Wheat straw board contains higher ash contents and increased levels of potassium, creating concern over fouling characteristics in Sauder's tight boiler design. In addition, the wheat straw board contains high concentrations of chlorine, which may affect boiler tube corrosion when fired in combination with the particleboard wastes currently generated. Sauder has engaged the services of the Energy & Environmental Research Center (EERC) at the University of North Dakota to investigate the potential detrimental effects of firing blends containing wheat straw on boiler tube fouling and corrosion. Additional funding for this project was provided through the U.S. Department of Energy Jointly Sponsored Research Program (DOE JSRP) project ''Validation of Fireside Performance Indices'' to validate, improve, and expand the PCQUEST (Predictive Coal Quality Effects Screening Tool) program. The PCQUEST fuel database is constantly expanding and adding new fuels, for which the algorithms may need refinement and additional verification in order to accurately predict index values. A key focus is on performing advanced and conventional fuel analyses and adding these analyses to the PCQUEST database. Such fuels include coals of all ranks and origins, upgraded coals, petroleum coke, biomass and biomass-coal blends, and waste materials blended with coal. Since there are differences in the chemical and mineral form of the inorganic content in biomass and substantial differences in organic matrix characteristics, analysis and characterization methods developed for coal fuels may not be applicable. The project was seen to provide an excellent opportunity to test and improve the ability of PCQUEST to handle nontypical soil and biomass minerals

Task 3.0: Advanced power systems. Semi-annual report, April 1--June 30, 1993

A variety of activities are incorporated into the Advanced Power Systems program. Tasks included are (1) fuel utilization properties, (2) pressurized combustion, (3) catalytic gasification, and (4) hot-gas cleanup. ATRAN is stochastic and combines initial coal inorganics in a random manner in order to predict the resulting fly ash particle size and composition. ASHPERT, is an expert system yielding a first-order estimate of fly ash size and composition. Both models are designed to emulate pulverized-coal combustion. Input data required include identity, chemistry, size, quantity, and mineral-to-coal associations. The pressurized combustion task has focused on the construction of a versatile reactor system to simulate pressurized fluidized-bed combustion. Both castable and monolithic refractories have been investigated in determining slag prevention under a variety of conditions. Catalytic gasification coupled with a molten carbonate fuel cell offers an extremely efficient and environmentally sound power generating system using coal. Work with an Illinois No. 6 bituminous coal has not been successful. Continued efforts will focus on using the more reactive low-rank coals to try to achieve this goal. Hot-gas cleanup is the critical issue in many of the proposed advanced power system operations on coal. The key to successful ash removal is an understanding of the properties of the ash to be collected as well as the interactions of this material with the barrier itself. The knowledge base under development will assist in assessing many of these barrier material issues for a variety of coal ashes

JV 58-Effects of Biomass Combustion on SCR Catalyst

A portable slipstream selective catalytic reduction (SCR) reactor was installed at a biomass cofired utility boiler to examine the rates and mechanisms of catalyst deactivation when exposed to biomass combustion products. The catalyst was found to deactivate at a much faster rate than typically found in a coal-fired boiler, although this may have been the result of high ash loading rather than a general property of biomass combustion. Deactivation was mainly the result of alkali and alkaline-earth sulfate formation and growth in catalyst pores, apparently caused by alkaline-earth ash deposition on or near the pore sites. The high proportion of biomass in the fuel contributed to elevated levels of alkali and alkaline-earth material in the ash when compared to coal ash, and these higher levels provided more opportunity for sulfate formation. Based on laboratory tests, neither catalyst material nor ammonia contributed measurably to ash mass gains via sulfation. A model constructed using both field and laboratory data was able to predict catalyst deactivation of catalysts under subbituminous coal firing but performed poorly at predicting catalyst deactivation under cofiring conditions. Because of the typically higher-than coal levels of alkali and alkaline-earth elements present in biomass fuels that are available for sulfation at typical SCR temperatures, the use of SCR technology and biomass cofiring needs to be carefully evaluated prior to implementation

EERC Center for Biomass Utilization 2006

The Center for Biomass Utilization (CBUî) 2006 project at the Energy & Environmental Research Center (EERC) consisted of three tasks related to applied fundamental research focused on converting biomass feedstocks to energy, liquid transportation fuels, and chemicals. Task 1, entitled Thermochemical Conversion of Biomass to Syngas and Chemical Feedstocks, involved three activities. Task 2, entitled Crop Oil Biorefinery Process Development, involved four activities. Task 3, entitled Management, Education, and Outreach, focused on overall project management and providing educational outreach related to biomass technologies through workshops and conferences

EERC Center for Biomass Utilization 2005

Biomass utilization is one solution to our nation’s addiction to oil and fossil fuels. What is needed now is applied fundamental research that will cause economic technology development for the utilization of the diverse biomass resources in the United States. This Energy & Environmental Research Center (EERC) applied fundamental research project contributes to the development of economical biomass utilization for energy, transportation fuels, and marketable chemicals using biorefinery methods that include thermochemical and fermentation processes. The fundamental and basic applied research supports the broad scientific objectives of the U.S. Department of Energy (DOE) Biomass Program, especially in the area of developing alternative renewable biofuels, sustainable bioenergy, technologies that reduce greenhouse gas emissions, and environmental remediation. Its deliverables include 1) identifying and understanding environmental consequences of energy production from biomass, including the impacts on greenhouse gas production, carbon emission abatement, and utilization of waste biomass residues and 2) developing biology-based solutions that address DOE and national needs related to waste cleanup, hydrogen production from renewable biomass, biological and chemical processes for energy and fuel production, and environmental stewardship. This project serves the public purpose of encouraging good environmental stewardship by developing biomass-refining technologies that can dramatically increase domestic energy production to counter current trends of rising dependence upon petroleum imports. Decreasing the nation’s reliance on foreign oil and energy will enhance national security, the economy of rural communities, and future competitiveness. Although renewable energy has many forms, such as wind and solar, biomass is the only renewable energy source that can be governed through agricultural methods and that has an energy density that can realistically compete with, or even replace, petroleum and other fossil fuels in the near future. It is a primary domestic, sustainable, renewable energy resource that can supply liquid transportation fuels, chemicals, and energy that are currently produced from fossil sources, and it is a sustainable resource for a hydrogen-based economy in the future

Trace metal transformation in gasification

The Energy & Environmental Research Center (EERC) is carrying out an investigation that will provide methods to predict the fate of selected trace elements in integrated gasification combined cycle (IGCC) and integrated gasification fuel cell (IGFC) systems to aid in the development of methods to control the emission of trace elements determined to be air toxics. The goal of this project is to identify the effects of critical chemical and physical transformations associated with trace element behavior in IGCC and IGFC systems. The trace elements included in this project are arsenic, chromium, cadmium, mercury, nickel, selenium, and lead. The research seeks to identify and fill, experimentally and/or theoretically, data gaps that currently exist on the fate and composition of trace elements. The specific objectives are to 1) review the existing literature to identify the type and quantity of trace elements from coal gasification systems, 2) perform laboratory-scale experimentation and computer modeling to enable prediction of trace element emissions, and 3) identify methods to control trace element emissions

The range and level of impurities in CO2 streams from different carbon capture sources

For CO2 capture and storage deployment, the impact of impurities in the gas or dense phase CO2 stream arising from fossil fuel power plants, or large scale industrial emitters, is of fundamental importance to the safe and economic transportation and storage of the captured CO2. This paper reviews the range and level of impurities expected from the main capture technologies used with fossil-fuelled power plants in addition to other CO2 emission-intensive industries. Analysis is presented with respect to the range of impurities present in CO2 streams captured using pre-combustion, post-combustion and oxy-fuel technologies, in addition to an assessment of the different parameters affecting the CO2 mixture composition. This includes modes of operation of the power plant, and different technologies for the reduction and removal of problematic components such as water and acid gases (SOx/NOx). A literature review of data demonstrates that the purity of CO2 product gases from carbon capture sources is highly dependent upon the type of technology used. This paper also addresses the CO2 purification technologies available for the removal of CO2 impurities from raw oxy-fuel flue gas, such as Hg and non-condensable compounds. CO2 purities of over 99% are achievable using post-combustion capture technologies with low levels of the main impurities of N2, Ar and O2. However, CO2 capture from oxy-fuel combustion and integrated gasification combined cycle power plants will need to take into consideration the removal of non-condensables, acid gas species, and other contaminants. The actual level of CO2 purity required will be dictated by a combination of transport and storage requirements, and process economics

Sulfur trioxide formation/emissions in coal‐fired air‐ and oxy‐fuel combustion processes: a review

In oxy‐fuel combustion, fuel is burned using oxygen together with recycled flue gas, which is needed to control the combustion temperature. This leads to higher concentrations of sulfur dioxide and sulfur trioxide in the recycled gas, which can result in the formation of sulfuric acid and enhanced corrosion. Current experimental data on SO3 formation, reaction mechanisms, and mathematical modelling have indicated significant differences in SO3 formation between air‐ and oxy‐fuel combustion for both the wet and dry flue gas recycle options. This paper provides an extensive review of sulfur trioxide formation in air‐ and oxy‐fuel combustion environments, with an emphasis on coal‐fired systems. The first part summarizes recent findings on oxy‐fuel combustion experiments, as they affect sulfur trioxide formation. In the second part, the review focuses on sulfur trioxide formation mechanisms, and the influence of catalysis on sulfur trioxide formation. Finally, the current methods for measuring sulfur trioxide concentration are also reviewed along with the major difficulties associated with those measurements using data available from both bench‐ and pilot‐scale units