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

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

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

Task 3.0 - Advanced Power Systems Subtask 3.18 - Ash Behavior in Power Systems

Ash behavior in power systems can have a significant impact on the design and performance of advanced power systems. The Energy & Environmental Research Center (EERC) has focused significant effort on ash behavior in conventional power systems that can be applied to advanced power systems. This initiative focuses on filling gaps in the understanding of fundamental mechanisms of ash behavior that has relevance to commercial application and marketable products. This program develops methods and means to better understand and mitigate adverse coal ash behavior in power systems and can act to relieve the U.S. reliance on diminishing recoverable oil resources, especially those resources that are not domestically available and are fairly uncertain

Year 2 Biomass Utilization: Final Technical Report

This Energy & Environmental Research Center (EERC) Year 2 Biomass Utilization Final Technical Report summarizes multiple projects in biopower or bioenergy, transportation biofuels, and bioproducts. A prototype of a novel advanced power system, termed the high-temperature air furnace (HITAF), was tested for performance while converting biomass and coal blends to energy. Three biomass fuels--wood residue or hog fuel, corn stover, and switchgrass--and Wyoming subbituminous coal were acquired for combustion tests in the 3-million-Btu/hr system. Blend levels were 20% biomass--80% coal on a heat basis. Hog fuel was prepared for the upcoming combustion test by air-drying and processing through a hammer mill and screen. A K-Tron biomass feeder capable of operating in both gravimetric and volumetric modes was selected as the HITAF feed system. Two oxide dispersion-strengthened (ODS) alloys that would be used in the HITAF high-temperature heat exchanger were tested for slag corrosion rates. An alumina layer formed on one particular alloy, which was more corrosion-resistant than a chromia layer that formed on the other alloy. Research activities were completed in the development of an atmospheric pressure, fluidized-bed pyrolysis-type system called the controlled spontaneous reactor (CSR), which is used to process and condition biomass. Tree trimmings were physically and chemically altered by the CSR process, resulting in a fuel that was very suitable for feeding into a coal combustion or gasification system with little or no feed system modifications required. Experimental procedures were successful for producing hydrogen from biomass using the bacteria Thermotoga, a deep-ocean thermal vent organism. Analytical procedures for hydrogen were evaluated, a gas chromatography (GC) method was derived for measuring hydrogen yields, and adaptation culturing and protocols for mutagenesis were initiated to better develop strains that can use biomass cellulose. Fly ash derived from cofiring coal with waste paper, sunflower hulls, and wood waste showed a broad spectrum of chemical and physical characteristics, according to American Society for Testing and Materials (ASTM) C618 procedures. Higher-than-normal levels of magnesium, sodium, and potassium oxide were observed for the biomass-coal fly ash, which may impact utilization in cement replacement in concrete under ASTM requirements. Other niche markets for biomass-derived fly ash were explored. Research was conducted to develop/optimize a catalytic partial oxidation-based concept for a simple, low-cost fuel processor (reformer). Work progressed to evaluate the effects of temperature and denaturant on ethanol catalytic partial oxidation. A catalyst was isolated that had a yield of 24 mole percent, with catalyst coking limited to less than 15% over a period of 2 hours. In biodiesel research, conversion of vegetable oils to biodiesel using an alternative alkaline catalyst was demonstrated without the need for subsequent water washing. In work related to biorefinery technologies, a continuous-flow reactor was used to react ethanol with lactic acid prepared from an ammonium lactate concentrate produced in fermentations conducted at the EERC. Good yields of ester were obtained even though the concentration of lactic acid in the feed was low with respect to the amount of water present. Esterification gave lower yields of ester, owing to the lowered lactic acid content of the feed. All lactic acid fermentation from amylose hydrolysate test trials was completed. Management activities included a decision to extend several projects to December 31, 2003, because of delays in receiving biomass feedstocks for testing and acquisition of commercial matching funds. In strategic studies, methods for producing acetate esters for high-value fibers, fuel additives, solvents, and chemical intermediates were discussed with several commercial entities. Commercial industries have an interest in efficient biomass gasification designs but are waiting for economic incentives. Utility, biorefinery, pulp and paper, or other industries are interested in lignin as a potential fuel or feedstock but need more information on properties