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A major objective of the US Department of Energy is to increase coal utilization through the development of combustion stream cleanup technologies. Many of the existing cleanup devices as well as advanced concepts rely on heterogeneous processes (i.e., gas-solid interactions) to achieve efficient stream removal. Examples of such devices include particle injection and granular bed filters for alkali removal, limestone injection for SO/sub x/ removal in fluid bed combustors, dry injection for SO/sub x/removal in entrained combustion, and trace metal adsorption and removal on fly ash. Recent studies indicate that the successful use of turbines in combined cycle processes may depend on understanding the interaction between the gas phase alkali and particles in the combustion stream to substantially reduce turbine corrosion. This report documents progress in efforts to model the heterogeneous chemistry of coal combustion streams as well as laboratory studies to obtain critical input data for the report. 5 references, 15 figures.

Accurate reporting of mercury concentration requires a detailed model that includes experimental parameters that vary, such as: pressure, temperature, concentration, absorption cross-section, and isotopic structure etc. During this quarter a theoretical model has been developed to model the 253.7 nm mercury transition. In addition, while testing the interferent species SO{sub 2}, SRD was able to determine the absorption cross-section experimentally and add this to the theoretical model. Assuming that the baseline losses are due to the mirror reflectivity and SO{sub 2}, SRD can now determine the concentrations of both mercury and SO{sub 2} from the data taken. For the CRD instrument to perform as a continuous emission monitor it will be required to monitor mercury concentrations over extended periods of time. The stability of monitoring mercury concentrations over time with the CRD apparatus was tested during the past quarter. During a test which monitored the mercury concentration every 2 seconds it was found that the standard deviation, of a signal from about 1.25 ppb Hg, was only 30 ppt. SRD continued interferent gas testing during this past quarter. This included creating a simulated flue gas composed of the gases tested individually by SRD. The detection limits for mercury, although dependent on the concentration of SO{sub 2} in the simulated gas matrix, remained well below the ppb range. It was determined that for the gases tested the only measurable changes in the baseline level occurred for SO{sub 2} and mercury. Speciation studies continued with mercury chloride (HgCl{sub 2}). This included checking for spectral speciation with both Hg and HgCl{sub 2} present in the CRD cavity. There was no observable spectral shift. Also a pyrolysis oven was incorporated into the gas delivery system both for tests with HgCl{sub 2} as well as atomization of the entire gas stream. The pyrolysis tests conducted have been inconclusive thus far.

The focus of the Phase 1 effort concerned further development of ZnO buffer layers. This work included further optimization of the metal-organic chemical vapor deposition (MOCVD) growth process and investigations of the interaction of zinc and oxygen with the absorber layers. Although much of the work had been done with Siemens' CIS material prior to this reporting period, a process for growing ZnO buffer layers on Siemens' CIGSS absorber had not been developed. The authors determined that a two-step procedure involving raising the substrate temperature to 250 C in nitrogen and then growing the buffer layer at 100 C works well with CIGSS material. Through collaboration with the Institute of Energy Conversion (IEC), completed cells with efficiencies in the 11% to 12% range were fabricated with the following structure: RF n-ZnO/i-ZnO/CIGSS. Cells with this structure were included as part of the Transient team studies. Cells were subjected to dark storage at 80 C, followed by a light soak at 40 C at IEC. Illuminated I-V curves taken at each stage of the study determined that these cells do not degrade under dark-storage conditions, which had been observed for Siemens cells with CdS buffer layers. To understand the reaction of zincmore » and oxygen with the absorber layers, secondary ion mass spectroscopy (SIMS) depth concentration profiles were obtained for i-ZnO/CIS structures through collaboration with Angus Rockett at the University of Illinois. SIMS profiles were obtained for ZnO films grown on polycrystalline CIS and epitaxial CIS films grown on GaAs. Comparison of the profiles strongly suggests that zinc and oxygen diffuse into the CIS along grain boundaries during the MOCVD growth process. It is also proposed that excess zinc along grain boundaries may result in the grain boundaries being n-type, which can result in enhanced loss currents. This model is consistent with the apparent requirement that cell structures with MOCVD buffer layers must undergo an aging process in air before efficient cells can be obtained. Future studies will investigate processes that allow the aging step to be eliminated.« less

The completion of the 5-MW Pilot Power Plant at the Raft River Geothermal Test Site, modification of the similar, binary cycle Prototype Power Plant, and the water treatment program that studies environmentally safe ways to inhibit corrosion and scaling in geothermal power plants and investigates corrosion resistant materials are summarized. Studies of binary geothermal cycles using mixed hydrocarbon working fluids are described as part of the continuing search for ways to produce low-cost electricity from moderate-temperature geothermal fluids. Progress is reported on studies of direct contact heat exchanger concepts, heat rejection systems, and primary heat exchangers with augmentation. As part of the now-ended series of aquaculture experiments, an unsuccessful attempt to incubate common carp embryos in geothermal waters is reported. An experiment in revegetating disturbed land at Raft River is mentioned and progress on DOE's new User Coupled Confirmation Drilling Program is described. An estimate is presented of the amount of hydrothermal energy that could be produced by the year 2000, with and without Federal assistance, for electric generation and direct applications such as industrial process heat. Progress is reported on the Marketing Assistance Program, through which technical information and assistance is provided potential users and developers of geothermal resources.more » Also reported is progress in DOE's Program Opportunity Notice (PON) Program demonstration projects and Program Research and Development Announcement (PRDA) Program study projects.« less

This report presents data from the chemical analysis and toxicological testing of coal liquefaction materials from the EDS and H-Coal processes operated using different ranks of coal. Samples of recycle solvent from the bottoms recycle mode of the EDS direct coal liquefaction process derived from bituminous, sub-bituminous, and lignite coals were analyzed. In addition, the H-Coal heavy fuel oils derived from bituminous and sub-bituminous coals were analyzed. Chemical methods of analysis included adsoprtion column chromatography, high-resolution gas chromatography, gas chromatography/mass spectrometry, and low-voltage probe-inlet mass spectrometry. The toxicological activity of selected samples was evaluated using the standard microbial mutagenicity assay, an initiation/promotion assay for mouse-skin tumorigenicity, and a static bioassy with Daphnia magna for aquatic toxicity of the water-soluble fractions. 22 refs., 16 figs., 14 tabs.

This document reports findings and recommendations as a result of a design assistance project with Fort Buchanan with the goals of developing a Water Management Plan (WMP). The WRMP developed during this task is an amalgam of the templates and guidelines from the Federal Energy Management Program and Army regulations.

Abstract Lignin is considered as a renewable and sustainable resource for producing value-added aromatic chemicals and functional carbon materials. Herein, we develop a one-step catalyst-free depolymerization strategy to convert lignin into aryl monomers and carbon nanospheres simultaneously. Importantly, microwave-assisted depolymerization (MAD) in conjunction with dichloromethane (CH2Cl2) vapors is developed. The total mass yield of guaiacols reached the highest amount of 225.1 mg/g at 600 °C, and the highest yields of phenols (49.0 mg/g) and aromatic hydrocarbons (155.1 mg/g) were obtained at 700 °C. Hydrogen radicals and hydrogen chloride (HCl) are in-situ formed from CH2Cl2, significantly decreasing the activation barrier and reforming pyrolysis vapors to promote the formation of aryl monomers. Interestingly, uniform carbon nanospheres with an average size of 140 nm were produced as co-products at 700 °C. The microwave “hot-spots”, allied with the continuous surface erosion and the decrease in surface energy of lignin-derived carbon precursors by CH2Cl2 vapor, can be considered the driving force for the ultimate formation of carbon nanospheres. The CH2Cl2/MAD system produces aryl monomers (26.8 wt% yield) and carbon nanospheres (36.6 wt% yield) at 700 °C. We provide a facile, intriguing and scalable approach to convert lignin to valuable aryl monomers and sustainable carbon materials that can be applied in the chemistry, energy and environmental fields.

Abstract Differential neutron-scattering cross-sections of 165 Ho are measured at 40 or more scattering angles and at ≈0.5 MeV incident-energy intervals from ≈4.5–10.0 MeV. These results are combined with previously-reported neutron total and scattering cross-sections to construct a comprehensive experimental data base which is interpreted in the context of a coupled-channels model, with attention to the collective excitation of the K =7/2 − ground-state rotational band. Physical aspects are discussed and comparisons made with previous models reported in the literature and with the relevant portions of the ENDF/B-6 evaluated nuclear data file.