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Description: The reaction rate of sodium sulfite was studied as a function of oxygen concentration, Na/sub 2/SO/sub 3//O/sub 2/ ratio, temperature, catalyst, pH and surface/volume ratio.The reaction rate of hydrazine with dissolved oxygen was also studied. Oxygen removal is incomplete when the sulfite to oxygen ratio is leas than the stoichiometric quantity. With the stoichiometric quantities of oxygen and sodium sulfite present, removal is incomplete at 100 deg F in 1 min, at 200 deg F, about 95% of the oxygen is removed in 10 sec and at 300 deg F oxygen removal is essentially complete in 10 sec. With an excess of sulfite present (10 Na/sub 2/SO/sub 3//1 O/sub 2/, molar), 95% of the oxygen is removed at 100 deg F in 10 sec. At 200 and 300 deg F, oxygen removal is essentially complete in 10 sec. The rate of oxygen removal is dependent to some extent on the container material. The sulfite oxygen reaction progresses at a higher rate in boiler water than in feedwater. The reaction rate of hydrazine with oxygen is low compared with the reaction rate of sulfite and dissolved oxygen. No reduction of oxygen was noted over a one-minute period with an excess of hydrazine. (auth)
Date: May 16, 1960
Creator: Rodgers, S.J.
Partner: UNT Libraries Government Documents Department

Mercury Volatility in the Presence of Reducing Agents

Description: This document described a laboratory study designed to determine whether mercury is, in fact, reduced by bisulfite ion and ammonia and, if so, whether the reduced mercury is volatilized at the boiling point of water. The primary conclusions resulting from this study are that both bisulfite ion and ammonia are capable of reducing mercury in solution and that, when reduced, the mercury will all be volatilized and carried into the distillate.
Date: March 23, 2001
Creator: Bibler, J.P.
Partner: UNT Libraries Government Documents Department

Microbial stabilization of sulfur-landen sorbents; Technical report, September 1--November 30, 1993

Description: Clean coal technologies that involve limestone for sulfur capture generate lime/limestone products laden with sulfur at various oxidation states. If sulfur is completely stabilized as sulfate, the spent sorbent is ready for commercial utilization as gypsum. However, the presence of reduced sulfur species requires additional processing. Thermal oxidation of reduced sulfur can result in undesirable release of SO{sub 2}. Microbial oxidation might provide an inexpensive and effective alternative. Sorbents laden with reduced forms of sulfur such as sulfide, sulfite, or various polythionate species serve as growth substrates for sulfur-oxidizing bacteria, which have the potential to convert all sulfur to sulfate. This quarter, efforts focused on determining the combined effects of dibasic acids (DBA) and Ca{sup +2} concentration on several strains of neutrophilic thiobacilli, including Thiobacillus neapolitanus ATCC 23639 and ATCC 23641, and an isolate, TQ1, which was obtained from a commercial sulfur dioxide scrubber that utilizes DBA.
Date: December 31, 1993
Creator: Miller, K.W.
Partner: UNT Libraries Government Documents Department


Description: Nanoscale montomorillonite (MMT) clay fillers became dispersed in a polyphenylenesulfied (PPS) matrix through the processes of octadecylamine (ODA) intercalation {yields} molten PPS co-intercalation {yields} exfoliation. Cooling this molten exfoliated material led to the formation of a PPS/MMT nanocomposite. The MMT nanofiller conferred three advanced properties on the semi-crystalline PPS: First, it raised its melting point by nearly 40 C to 290 C; second, it increased its crystallization energy, implying that an excellent adherence of the nanofillers surfaces to PPS in terms of a good interfacial bond; and, third, it abated the degree of its hydrothermal oxidation due to sulfide {yields} sulfite linkage transformations. When this advanced PPS nanocomposite was used as a corrosion-preventing coating for carbon steel in a simulated geothermal environment at 300 C, a coating of {approx}150 {micro}m thickness adequately protected the steel against hot brine-caused corrosion. In contrast, an MMT-free PPS coating of similar thickness was not nearly as effective in mitigating corrosion as was the nanocompsite; in fact, the uptake of corrosive ionic electrolyte by the unmodified coating increased with an extending exposure time.
Date: June 1, 2006
Creator: SUGAMA, T. & GAWLIK, K.
Partner: UNT Libraries Government Documents Department


Description: This report describes the results from RPP-PLAN-32738, 'Test Plan for the Effluent Treatment Facility to Reduce Chrome(VI) to Chrome(I1I) in the Secondary Waste Stream', using sodium metabisulfite. Appendix A presents the report as submitted by the Center for Laboratory Sciences (CLS) to CH2M HILL Hanford Group, Inc. The CLS carried out the laboratory effort under Contract Number 21065, release Number 30. This report extracts the more pertinent aspects of the laboratory effort.
Date: July 18, 2007
Partner: UNT Libraries Government Documents Department


Description: The authors evaluated the usefulness of nanoscale boehmite crystals as a filler for anti-wear and anti-corrosion polyphenylenesulfide (PPS) coatings exposed to a very harsh, 300 C corrosive geothermal environment. The boehmite fillers dispersed uniformly into the PPS coating, conferring two advanced properties: First, they reduced markedly the rate of blasting wear; second, they increased the PPS's glass transition temperature and thermal decomposition temperature. The wear rate of PPS surfaces was reduced three times when 5wt% boehmite was incorporated into the PPS. During exposure for 15 days at 300 C, the PPS underwent hydrothermal oxidation, leading to the substitution of sulfide linkages by the sulfite linkages. However, such molecular alteration did not significantly diminish the ability of the coating to protect carbon steel against corrosion. In fact, PPS coating filled with boehmite of {le} 5wt% adequately mitigated its corrosion in brine at 300 C. One concern in using this filler was that it absorbs brine. Thus, adding an excess amount of boehmite was detrimental to achieving the maximum protection afforded by the coatings.
Date: June 26, 2003
Creator: SUGAMA,T.
Partner: UNT Libraries Government Documents Department

Value-Added Products from FGD Sulfite-Rich Scrubber Materials

Description: According to the American Coal Ash Association, about 29.25 million tons of flue gas desulfurization (FGD) byproducts were produced in the USA in 2003. Out of 29.25 million tons, 17.35 million tons were sulfite-rich scrubber materials. At present, unlike its cousin FGD gypsum, the prospect for effective utilization of sulfite-rich scrubber materials is not bright. In fact, almost 16.9 million tons are leftover every year. In our pursuit to mitigate the liability of sulfite-rich FGD scrubber materials' disposal, we are attempting to develop value-added products that can commercially compete. More specifically, for this Innovative Concept Phase I project, we have the following objectives: to characterize the sulfite-rich scrubber material for toxic metals; to optimize the co-blending and processing of scrubber material and natural byproducts; to formulate and develop structural composites from sulfite-rich scrubber material; and to evaluate the composites' mechanical properties and compare them with current products on the market. After successfully demonstrating the viability of our research, a more comprehensive approach will be proposed to take these value-added materials to fruition.
Date: January 31, 2010
Creator: Malhotra, Vivak
Partner: UNT Libraries Government Documents Department

Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans Under Aerobic vs. Denitrifying Conditions

Description: Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with ke chemolithoautotrophic functions (such as sulfur-compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately ten percent of the genome) as differentially expressed using Robust Multi-array Average statistical analysis and a 2-fold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated respectively with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur-compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription, quantitative PCR analysis was used to validate these trends.
Date: April 22, 2006
Creator: Beller, H R; Letain, T E; Chakicherla, A; Kane, S R; Legler, T C & Coleman, M A
Partner: UNT Libraries Government Documents Department

Full-Scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System

Description: This document presents and discusses results from Cooperative Agreement DE-FC26-06NT42778, 'Full-scale Testing of a Mercury Oxidation Catalyst Upstream of a Wet FGD System,' which was conducted over the time-period July 24, 2006 through June 30, 2010. The objective of the project was to demonstrate at full scale the use of solid honeycomb catalysts to promote the oxidation of elemental mercury in pulverized-coal-fired flue gas. Oxidized mercury is removed downstream in wet flue gas desulfurization (FGD) absorbers and collected with the byproducts from the FGD system. The project was co-funded by EPRI, the Lower Colorado River Authority (LCRA), who also provided the host site, Great River Energy, Johnson Matthey, Southern Company, Salt River Project (SRP), the Tennessee Valley Authority (TVA), NRG Energy, Ontario Power and Westar. URS Group was the prime contractor and also provided cofunding. The scope of this project included installing and testing a gold-based catalyst upstream of one full-scale wet FGD absorber module (about 200-MW scale) at LCRA's Fayette Power Project (FPP) Unit 3, which fires Powder River Basin coal. Installation of the catalyst involved modifying the ductwork upstream of one of three wet FGD absorbers on Unit 3, Absorber C. The FGD system uses limestone reagent, operates with forced sulfite oxidation, and normally runs with two FGD modules in service and one spare. The full-scale catalyst test was planned for 24 months to provide catalyst life data. Over the test period, data were collected on catalyst pressure drop, elemental mercury oxidation across the catalyst module, and mercury capture by the downstream wet FGD absorber. The demonstration period began on May 6, 2008 with plans for the catalyst to remain in service until May 5, 2010. However, because of continual increases in pressure drop across the catalyst and concerns that further increases would adversely affect Unit 3 operations, ...
Date: June 30, 2010
Creator: Blythe, Gary & Paradis, Jennifer
Partner: UNT Libraries Government Documents Department

Clear Liquor Scrubbing with Anhydrite Production

Description: The objective of this project to develop an advanced flue gas desulfurization (FGD) process that has decreased capital and operating costs, higher SO{sub 2} removal efficiency, and better by-product solids quality than existing, commercially available technology. A clear liquor process (which uses a scrubbing liquid with no solids) will be used to accomplish this objective rather than a slurry liquor process (which contains solids). This clear liquor scrubbing (CLS) project is focused on three research areas: (1) Development of a clear liquor scrubbing process that uses a clear solution to remove SO{sub 2} from flue gas and can be operated under inhibited-oxidation conditions; (2) Development of an anhydrite process that converts precipitated calcium sulfite to anhydrous calcium sulfate (anhydrite); and (3) Development of an alkali/humidification process to remove HCl from flue gas upstream of the FGD system. The anhydrite process also can be retrofit into existing FGD systems to produce a valuable by-product as an alternative to gypsum. This fits well into another of FETC's PRDA objectives of developing an advanced byproduct recovery subsystem capable of transforming SO{sub 2} into a useable byproduct or high-volume valuable commodities of interest. This paper describes the proposed processes, outlines the test approach, and preliminary Phase I test results.
Date: July 1, 1997
Creator: Hargrove, O. W.; Carey, T. R.; Lowell, P. S.; Meserole, F. B.; Rhudy, R. G. & Feeley, Thomas J.
Partner: UNT Libraries Government Documents Department


Description: The aim of this project is to delineate the role of mineralogy of reservoir rocks in determining interactions between reservoir minerals and externally added reagents (surfactants/polymers) and its effect on critical solid-liquid and liquid-liquid interfacial properties such as adsorption, wettability and interfacial tension in systems relevant to reservoir conditions. Previous studies have suggested that significant surfactant loss by precipitation or adsorption on reservoir minerals can cause chemical schemes to be less than satisfactory for enhanced oil recovery. Both macroscopic adsorption, wettability and microscopic orientation and conformation studies for various surfactant/polymer mixtures/reservoir rocks systems were conducted to explore the cause of chemical loss by means of precipitation or adsorption, and the effect of rock mineralogy on the chemical loss. During this period, the adsorption of mixed system of n-dodecyl-{beta}-D-maltoside (DM) and dodecyl sulfonate (C{sub 12}SO{sub 3}Na) has been studied. The effects of solution pH, surfactant mixing ratio and different salts on surfactant adsorption on alumina have been investigated in detail. Along with these adsorption studies, changes in mineral wettability due to the adsorption of the mixtures were determined under relevant conditions to identify the nano-structure of the adsorbed layers. Solution properties of C{sub 12}SO{sub 3}Na/DM mixtures were also studied to identify surfactant interactions that affect the mixed aggregate formation in solution. Adsorption of SDS on gypsum and limestone suggested stronger surfactant/mineral interaction than on alumina, due to the precipitation of surfactant by dissolved calcium ions. The effects of different salts such as sodium nitrate, sodium sulfite and sodium chloride on DM adsorption on alumina have also been determined. As surfactant hemimicelles at interface and micelles in solution have drastic effects on oil recovery processes, their microstructures in solutions and at mineral/solution interfaces were investigated by monitoring micropolarity of the aggregates using fluorescence technique. Compositional changes of the aggregates in solution were ...
Date: April 30, 2005
Creator: Somasundaran, P.
Partner: UNT Libraries Government Documents Department

Effect of the deletion of qmoABC and the promoter distal gene encoding a hypothetical protein on sulfate-reduction in Desulfovibrio vulgaris Hildenborough

Description: The pathway of electrons required for the reduction of sulfate in sulfate-reducing bacteria (SRB) is not yet fully characterized. In order to determine the role of a transmembrane protein complex suggested to be involved in this process, a deletion of Desulfovibrio vulgaris Hildenborough was created by marker exchange mutagenesis that eliminated four genes putatively encoding the QmoABC complex and a hypothetical protein (DVU0851). The Qmo complex (quinone-interacting membrane-bound oxidoreductase) is proposed to be responsible for transporting electrons to the dissimilatory adenosine-5?phosphosulfate (APS) reductase in SRB. In support of the predicted role of this complex, the deletion mutant was unable to grow using sulfate as its sole electron acceptor with a range of electron donors. To explore a possible role for the hypothetical protein in sulfate reduction, a second mutant was constructed that had lost only the gene that codes for DVU0851. The second constructed mutant grew with sulfate as the sole electron acceptor; however, there was a lag that was not present with the wild-type or complemented strain. Neither deletion strain was significantly impaired for growth with sulfite or thiosulfate as terminal electron acceptor. Complementation of the D(qmoABC-DVU0851) mutant with all four genes or only the qmoABC genes restored its ability to grow by sulfate respiration. These results confirmed the prediction that the Qmo complex is in the electron pathway for sulfate-reduction and revealed that no other transmembrane complex could compensate when Qmo was lacking.
Date: March 18, 2010
Creator: Zane, Grant M.; Yen, Huei-chi Bill & Wall, Judy D.
Partner: UNT Libraries Government Documents Department

Field-Scale Evaluation of Biological Uranium Reduction and Reoxidation in the Near-Source Zone at the NABIR Field Research Center in Oak Ridge, TN

Description: We have now added ethanol intermittently for over 700 days. Ethanol has been added weekly with each injection lasting for a few days. We are now observing: (1) Uranium immobilization at 700-2000 mg/kg. Baseline levels before remediation were 30-500 mg/kg. (2) Uranium concentrations in groundwater at the monitoring wells have fallen below the U.S. drinking water standard (30 ppb). This is an important milestone. (3) XANES analyses for day 535 indicate 51% U(IV) at the inner loop injection well, 35% U(IV) at MLS well 101-2, and 28% U(IV) at the extraction well. These numbers indicate that U(IV) reduction is not localized to the injection well, and is spreading through the aquifer. (4) We have had success removing trace levels of oxygen from recirculated water by addition of sulfite and related compounds. These compounds also provide the added benefit that in removing oxygen that themselves are oxidized to sulfate, an important electron acceptor needed for maintenance of our system.
Date: June 1, 2006
Creator: Criddle, Craig S.
Partner: UNT Libraries Government Documents Department

Post-Translational Modifications of Desulfovibrio vulgaris Hildenborough Sulfate Reduction Pathway Proteins

Description: Recent developments in shotgun proteomics have enabled high-throughput studies of a variety of microorganisms at a proteome level and provide experimental validation for predicted open reading frames in the corresponding genome. More importantly, advances in mass spectrometric data analysis now allow mining of large proteomics data sets for the presence of post-translational modifications(PTMs). Although PTMs are a critical aspectof cellular activity, such information eludes cell-wide studies conducted at the transcript level. Here, we analyze several mass spectrometric data sets acquired using two-dimensional liquid chromatography tandem mass spectrometry, 2D-LC/MS/MS, for the sulfate reducing bacterium, Desulfovibrio vulgaris Hildenborough. Our searches of the raw spectra led us to discover several post-translationally modified peptides in D. vulgaris. Of these, several peptides containing a lysine with a +42 Da modification were found reproducibly across all data sets. Both acetylation and trimethylation have the same nominal +42 Da mass, and are therefore candidates for this modification. Several spectra were identified having markers for trimethylation, while one is consistent with an acetylation. Surprisingly, these modified peptides predominantly mapped to proteins involved in sulfate respiration. Other highly expressed proteins in D. vulgaris, such as enzymes involved in electron transport and other central metabolic processes, did not contain this modification. Decoy database searches were used to control for random spectrum/sequence matches. Additional validation for these modifications was provided by alternate workflows, for example, two-dimensional gel electrophoresis followed by mass spectrometry analysis of the dissimilatory sulfite reductase gamma-subunit(DsrC) protein. MS data for DsrC in this alternate workflow also contained the +42 Da modification at the same loci. Furthermore, the DsrC homologue in another sulfate reducing bacterium, Desulfovibrio desulfuricans G20, also showed similar +42 Da modifications in the same pathway. Here, we discuss our methods and implications of potential trimethylation in the D. vulgaris sulfate reduction pathway.
Date: March 1, 2008
Creator: Gaucher, S.P.; Redding, A.M.; Mukhopadhyay, A.; Keasling, J.D. & Singh, A.K.
Partner: UNT Libraries Government Documents Department

The Role of the Tetraheme Cytochrome c3 in Desulfovibrio vulgaris Hildenborough Metabolism

Description: The role of tetraheme cytochrome c3 (CycA) in the metabolism of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough (DvH) was investigated by deletion of the cycA gene using a marker-exchange deletion strategy. A highly abundant periplasmic cytochrome, CycA has the important function of transferring electrons from periplasmic hydrogenases (Hyd, Hyn, Hys) to transmembrane complexes which transport the electrons to the cytoplasm where sulfate is reduced. Previous studies have indicated that during its interaction with periplasmic hydrogenases, CycA is also involved in the reduction of toxic metals. Growth of the cycA mutant strain on lactate as the electron donor and sulfate as the terminal electron acceptor showed that, despite its abundance, CycA is not essential for DvH growth. However, the rate of growth of the mutant strain was significantly lower, and the extent of growth less, than rates and extents of growth of the wild type and complement strains on lactate/sulfate medium. This indicates that a portion of the electrons generated from cytoplasmic lactate oxidation are transported by CycA for energy production, possibly in a hydrogen cycling mechanism employed to generate ATP. Failure of the mutant strain to grow on either formate or H2, with sulfate or sulfite as electron acceptors, further indicated that CycA may be the only redox partner of periplasmic hydrogenases. The cycA mutant strain also did not grow as well as either the wild type or complement strains on medium supplemented with pyruvate/sulfate. Final growth on pyruvate/sulfate was comparable, but the mutant grew more slowly than the wild type and complement strains. Interestingly, the mutant grew better than the wild type or complement strains on pyruvate alone, possibly due to the release of H2 and/or CO2 in concentrations which may be somewhat inhibitory to wild type growth.
Date: May 17, 2010
Creator: Semkiw, Elizabeth; Zane, Grant & Wall, Judy
Partner: UNT Libraries Government Documents Department


Description: The possibility of measuring the electromagnetic form factor of the pion by extrapolation of the cross section for e/sup -/ + p 1100 deg C are n + The effects of /sup +/ + e/sup -/ was investigated. The method is based on the existence of a pole in the electropionproduction scattering amplitude as a function of the invariant momentum-transfer of the nucleon. The residue of this pole is the pion form factor multiplied by a known coefficient. Since the pole lies slightly outside the physical region of the invariant momentum transfer, an extrapolation of the experimental data is required. An approximate calculation of the electropion-production cross section was made in order to estimate the experimental accuracy necessary for a significant extrapolation. Accuracy is required which is an order of magnitude better than that achieved at present in similar experiments. (auth)
Date: February 1, 1959
Creator: Frazer, W.R.
Partner: UNT Libraries Government Documents Department

Advanced separation technology for flue gas cleanup. Quarterly technical report No. 14

Description: The objective of this work is to develop a novel system for regenerable SO{sub 2} and NO{sub x} scrubbing of flue gas that focuses on (a) a novel method for regeneration of spent SO{sub 2} scrubbing liquor and (b) novel chemistry for reversible absorption of NO{sub x}. In addition, high efficiency hollow fiber contactors (HFC) are proposed as the devices for scrubbing the SO{sub 2} and NO{sub x} from the flue gas. The system will be designed to remove more than 95% of the SO{sub x} and more than 75% of the NO{sub x} from flue gases typical of pulverized coal-fired power plants at a cost that is at least 20% less than combined wet limestone scrubbing of SO{sub x} and selective catalytic reduction NO{sub x}. In addition, the process will make only marketable byproducts, if any (no waste streams). During the third quarter of 1995, we continued work on Task 8, integrated NO{sub x} life tests. We also obtained some mass transfer data on Task 9, performance of scalable modules. In Task 8, we gathered additional 400 hours of NO{sub x} absorption/desorption data. We also presented the data on NO{sub x} absorption/desorption behavior over cumulative time to date. the performance indicates unchanged reversible characteristics of Co(II) phthalocyanine solution. Therefore, we believe that NO{sub x} absorption/desorption chemistry is robust. In Task 9, we experimentally observed the channeling of liquid flow due to poor design of previous rectangular modules. Newly obtained welded rectangular modules out-performed previous modules. We also presented SO{sub 2} absorption data using different Na{sub 2}SO{sub 3} concentrations. The SO{sub 2} absorption seem to be dependent on liquid flow rate, a rather surprising result compared to earlier results. Apparatus for combined absorption/desorption of SO{sub 2} in rectangular modules is also given in this report.
Date: November 1, 1995
Creator: Bhown, A.S.; Pakala, N.; Riggs, T.; Tagg, T.; Kirkar, K.K.; Majumdar, S. et al.
Partner: UNT Libraries Government Documents Department

Separation of flue-gas scrubber sludge into marketable products. Quarterly technical progress report No. 12, June 1, 1996--August 30, 1996

Description: To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of. This sludge is a result of reacting limestone with sulfur dioxide to precipitate calcium sulfite and calcium sulfate. It consists of calcium sulfite, gypsum, and unreacted limestone or lime, with miscellaneous objectionable impurities such as iron oxides, silicates, and magnesium, sodium, and potassium oxides or salts. These impurities prevent many sludges from being utilized as a replacement for natural gypsum, and as a result they must be disposed of in landfills, which presents a serious disposal problem. Knowledge of scrubber sludge characteristics is necessary for the development of purification technologies which will make it possible to directly utilize scrubber sludges rather then landfilling them. This project is studying the use of minimal-reagent froth flotation as the purification process, using the surface properties of the particles of unreacted limestone to remove them and their associated impurities from the material, leaving a purified calcium sulfite/gypsum product. In this quarter, the installation of a laboratory-scale flotation column was completed. In addition to the installation of the flotation column, research on the determination of the surface properties of the components of the scrubber sludge was continued. Auger electron spectroscopy was investigated as a method for determining the composition of the first few monolayers of unreacted limestone and calcium sulfite/sulfate particles.
Date: September 1, 1996
Creator: Kawatra, S.K. & Eisele, T.C.
Partner: UNT Libraries Government Documents Department

Separation of flue-gas scrubber sludge into marketable products. Third year, second quarterly technical progress report, December 1, 1995--February 29, 1996 (Quarter {number_sign}10)

Description: To reduce their sulfur emissions, many coal-fired electric power plants use wet flue-gas scrubbers. These scrubbers convert sulfur oxides into solid sulfate and sulfite sludge, which must then be disposed of. Knowledge of scrubber sludge characteristics is necessary for the development of purification technologies which will make it possible to directly utilize scrubber sludges rather than landfilling them. This project is studying the use of minimal-reagent froth flotation as the purification process, using the surface properties of the particles of unreacted limestone to remove them and their associated impurities from the material, leaving a purified calcium sulfite/gypsum product. In the current quarter, research was focused on two different areas. The first part of this quarter the optimization of the feed slurry percent solids for the two inch water-only cyclone was completed. The optimization of the vortex finder, spigot diameter and inlet feed pressure was completed in the previous quarter. The second part of this quarter began the investigation of why water-only cycloning helps froth flotation performance. The hypothesis is that water-only cycloning scrubs the surface of the unreacted limestone. This scrubbing effect provides a clean calcium carbonate surface, which results in better flotation reagent adsorption. This study used the scanning electron microscope to investigate the surface of the unreacted limestone particles.
Date: March 1, 1996
Creator: Kawatra, S.K. & Eisele, T.C.
Partner: UNT Libraries Government Documents Department

Studies of chemical reduction of Fe(III)*EDTA in an SO{sub 2}/NO{sub x} aqueous scrubber system

Description: Ferrous*EDTA has been found to be an effective scrubbing agent for nitric oxide gas. A major process problem is oxidation of the iron to the ferric species, leading to a significant decrease in NO{sub x}-removal capability. Argonne National Laboratory discovered a class of organic compounds that, when used with ferrous*EDTA in a sodium carbonate chemistry, could maintain high levels of NO{sub x} removal. However, those antioxidant/reducing agents (A/R) are not effective in a lime-based chemistry. In recent reports, it has been found that ascorbic acid and related compounds are capable of maintaining stable NO{sub x} removals of about 50% (compared with about 15% without the agent) in a lime-based FGD chemistry with Fe(II)*EDTA. It is believed that the improved performance of Fe(II)*EDTA is due to the catalytic action of ascorbate in the Fe(III)*EDTA reduction system, where Fe(III)*EDTA is reduced by ascorbate and oxidized ascorbate is then reduced back to the ascorbate by sulfite/bisulfite anions, which come from the dissolution of SO{sub 2} in the flue gas. In the present work, the kinetics of the reduction of ferric chelate by ascorbate and reduction of oxidized ascorbate by sulfite/bisulfite anions at a typical flue-gas scrubber-system operating temperature ({approximately}55 C) have been determined.
Date: March 1, 1996
Creator: Li, W.; Keener, T.C.; Mendelsohn, M.; Harkness, J.B.L. & Livengood, C.D.
Partner: UNT Libraries Government Documents Department

Separation of Flue-Gas Scrubber Sludge into Marketable Products

Description: The reduction of sulfur oxides from high sulfur coal burning utility companies has resulted in the production of huge quantities of wet flue-gas desulfurization scrubber sludge. A typical 400 MW power station burning a coal containing 3.5% sulfur by weight and using a limestone absorbent would produce approximately 177,000 tons (dry weight) of scrubber sludge per year. This brownish colored, finely divided material contains calcium sulfite (CaSO{sub 3} {center_dot} 1/2 H{sub 2}O), calcium sulfate (CaSO{sub 4} {center_dot} 2H{sub 2}O), unreacted limestone (CaCO{sub 3}), and various other impurities such as fly-ash and iron oxide particles. The physical separation of the components of scrubber sludge would result in the re-use of this material. The primary use would be conversion to a highly pure synthetic gypsum. This technical report concentrates on the effect of baffle configuration on the separation of calcium sulfite/sulfate from limestone. The position of the baffles as they related to the feed inlet, and the quantity of the baffles were examined. A clean calcium sulfite/sulfate (less than 2.0% limestone by weight) was achieved with the combination of water-only cyclone and horizontally baffled column.
Date: February 28, 1998
Partner: UNT Libraries Government Documents Department


Description: Prior to the initiation of this study, understanding of the long-term behavior of environmentally-exposed Coal Combustion By-Products (CCBs) was lacking in (among others) two primary areas addressed in this work. First, no method had been successfully applied to achieve full quantitative analysis of the partitioning of chemical constituents into reactive or passive crystalline or noncrystalline compounds. Rather, only semi-quantitative methods were available, with large associated errors. Second, our understanding of the long-term behavior of various CCBs in contact with the natural environment was based on a relatively limited set of study materials. This study addressed these areas with two objectives, producing (1) a set of protocols for fully quantitative phase analysis using the Rietveld Quantitative X-ray Diffraction (RQXRD) method and (2) greater understanding of the hydrologic and geochemical nature of the long-term behavior of disposed and utilized CCBs. The RQXRD technique was initially tested using (1) mixtures of National Institute of Standards and Technology (NIST) crystalline standards, and (2) mixtures of synthetic reagents simulating various CCBs, to determine accuracy and precision of the method, and to determine the most favorable protocols to follow in order to efficiently quantify multi-phase mixtures. Four sets of borehole samples of disposed or utilized CCBs were retrieved and analyzed by RQXRD according to the protocols developed under the first objective. The first set of samples, from a Class F ash settling pond in Kentucky disposed for up to 20 years, showed little mineralogical alteration, as expected. The second set of samples, from an embankment in Indiana containing a mixture of chain-grate (stoker) furnace ash and fluidized bed combustion (FBC) residues, showed formation of the mineral thaumasite, as observed in previously studied exposed FBC materials. Two high-calcium CCBs studied, including a dry-process flue gas desulfurization (FGD) by-product disposed in the Midwest, and a mixture of Class ...
Date: January 1, 2001
Creator: McCarthy, Gregory J. & Grier, Dean G.
Partner: UNT Libraries Government Documents Department

Limitations of retarded (bisulfite) x-ray film processing

Description: We demonstrate the limitations of using retarded (bisulfite) developer to abate film sensitivity of x-ray films that have been exposed to intense radiation. We compared the measured densities of a large number of Kodak Type-M x-ray film samples exposed to a known fluence of monochromatic x-rays. These film samples were processed in three separate batches of bisulfite developer mixed in the same proportions. We concluded that reproducible film-density information cannot be obtained using different batches of (bisulfite) developer solutions.
Date: October 16, 1979
Creator: Stoering, J.P. & Dittmore, C.
Partner: UNT Libraries Government Documents Department