Kurt E. Eylands

Mercury capture on coal combustion fly ash

Abstract A study was performed at the Energy and Environmental Research Center (EERC) to test the hypotheses that (1) different carbon types contained in coal combustion fly ash have variable sorption capabilities relative to mercury and (2) the inorganic fraction of coal combustion fly ash may sorb mercury through mechanisms distinct from sorption by carbon in the ash. The purpose of this study was to conduct laboratory experiments to better understand the phenomenon of mercury sorption on coal combustion fly ash. Tests were conducted on the laboratory scale using samples generated from both commercial-scale utility boilers and pilot-scale combustion equipment at the EERC. Selected samples represented ash from various coal sources, of varying loss-on-ignition (LOI) content, and exhibiting different combinations of carbon types. Results indicate a direct correlation between carbon content and mercury partitioning among individual ash samples. The direct relationship between carbon content and mercury-sorbing capacity of the bulk ash samples demonstrated in the loading experiments is not reflected by the low- and high-carbon fraction data. The mercury-sorbing capacity of the inorganic fraction is extremely low with respect to carbon present in the ash. There are likely to be significant differences between the mercury-sorbing capacities of these various carbon forms. The mercury-sorbing capacity of ash studied in this research was highly temperature dependent. Additional work is needed on experimental design to evaluate the loading of high-carbon ash samples with particular attention to the phenomenon of sorptive capacity regeneration, which should be further investigated.

Heat of hydration of fly ash as a predictive tool

A test procedure based on heat of hydration was developed to assess more accurately the reactivity and behaviour of fly ash for utilization. The technique uses a Dewar flask or a modified oxygen bomb calorimeter to determine the temperature change and rate of change after the addition of water to fly ash. X-ray diffraction is performed on the hydrated material after the hydration test to follow mineralogical changes due to the hydration process. A study of coal ash samples is under way to determine whether correlations exist between the temperature change and results from empirical tests, such as those of the ASTM, used to determine properties of ash for engineering applications. A protocol has been developed for an improved classification scheme for coal ash.

Comparison of the pyrometamorphism of clayey rocks during underground coal gasification and firing of structural ceramics

Abstract Underground coal gasification (UCG), an unconventional technique of coal utilization, is associated with large-scale firing of rocks adjacent to the coal seam. A significant fraction of these rocks are argillaceous and have a composition comparable to mixes of raw material utilized in brickmaking, and in the manufacturing of lightweight aggregates which employes a bloating and expansion fabrication mechanism.

An Assessment of Residues from Duct Injection Demonstration Sites

The duct injection retrofit process for flue gas cleanup of sulfur dioxide emissions has been demonstrated at several sites in the United States through a series of U.S. Department of Energy research projects. As a subcontractor on one of the projects, the University of North Dakota Energy & Environmental Research Center performed a comprehensive characterization of four residues from three demonstration sites. The characterization task objective was to facilitate understanding of materials handling and to identify potential disposal and utilization options for these high-volume coal utilization solid residues. Characterization included evaluation of the physical and engineering properties, chemical composition, mineralogy, and leaching potential. Chemical characterization results provided interesting and valuable information from the standpoint of the bulk chemistry and phase assemblages, as well as potential environmental issues associated with the use or disposal of these materials. Results of the chem...

Characterization of Particulate Matter with Computer-Controlled Scanning Electron Microscopy

Particulate matter samples were obtained from three upper Midwest locations with a Burkard spore-sampling device and automatic cartridge collection unit (ACCU) filter for computer-controlled scanning electron microscopy analysis. The sites consisted of two rural sites and one urban site. All samples from the Burkard sampler contained high levels of organic components such as topsoil, spores, wheat chaff, and others. The inorganic components consisted of quartz, clays, feldspars, and carbonates. Approximately 15% of the particles collected by the ACCU filter at Rural Site B had a shape factor that suggests the particles may be from a combustion process. In addition, the level of sulfates in the ACCU sample was 16%, with calcium and ammonium sulfates being most abundant.

ADVANCED SAMPLING AND ANALYSIS OF FINE PARTICULATES. Final Topical Report which includes semiannual for the period of January 1, 1998 - June 30, 1998

Sampling tests indicated that the polycarbonate filters were marginally acceptable for in-stack fine-particle collection because of their 230 F melting point as well as requiring carbon coating to reduce charging effects. Vitreous carbon substrates, although not porous, have acceptable thermal stability as well as acceptable levels of charging. A porous silver membrane filter is also being considered for future testing. Pure reference samples of secondary aerosols have been successfully been collected on vitreous carbon substrates with good dispersion and found suitable for direct examination by scanning electron microscope (SEM) without prior coating or preparation. These samples will be used to develop optimum SEM measurement and quantification techniques related to the analysis of fine secondary aerosols.