80 Matching Results

Search Results

Advanced search parameters have been applied.

Thorium ceramics data manual. Volume II. Nitrides. Revised

Description: Physical, chemical, and mechanical properties of thorium nitrides, alone and in combination with other nitrides and other thorium compounds. are collected from the literature through January 1973 (51 references). The thorium-nitrogen phase equilibrium is reviewed. Although mechanical property data are still sparse, recent physical and chemical characterization of ThN has confirined its high metallic conductivity, furnished detaii on hydrolysis and oxidation, and expanded the knowledge of the (Th,U)N and Th(C,N) systems. (auth)
Date: October 1, 1973
Creator: Peterson, S. & Curtis, C.E.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins

Description: The objective of this project is to evaluate the efficacy of low severity coal liquefaction in the presence of highly reactive hydrogen donors, cyclic olefins. The work that was performed this quarter involved performing a literature search in which different aspects of low severity coal liquefaction were examined. In addition, two new mater's graduate students learned the fundamental differences between high severity coal liquefaction and low severity coal liquefaction by examining the literature and reading texts on coal liquefaction. The literature review presented for the first quarter's work is a compilation of the material which we have found to data involving low severity coal liquefaction. Additional review of low severity liquefaction literature is being conducted this quarter and will be reported in the next quarterly report. In addition, a summary of the work involving the reactivity of cyclic olefins in the absence and presence of coal will be presented next quarter.
Date: January 1, 1991
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Mild acidic pretreatment to enhance low severity coal liquefaction promoted by cyclic olefins. Quarterly report, July 1995--September 1995

Description: Research continued on low severity coal liquefaction. Research using high temperature infrared of cyclic olefins progressed well during this quarter. Several fluorinated solvents were found that provide a high temperature medium for isotetralin and its aromatic and aliphatic analogues.
Date: March 1, 1996
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins. Quarterly report, April--June, 1995

Description: The goal of this research is to develop a methodology for analyzing the reactivity of cyclic alkenes in situ in a high temperature and high pressure infrared cell. Cyclic alkenes are highly reactive donors of hydrogen to coal in low severity coal liquefaction.
Date: January 1, 1996
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Role of the resid solvent in catalytic coprocessing with finely divided catalysts. Quarterly report, January--March 1995

Description: The research reported in this progress report describes the continuation of coal-resid coprocessing reactions that were discussed in the July to September 1994 Quarterly Report. During previous quarters, Maya and FHC-623 resids were evaluated in noncatalytic and catalytic reactions at 400{degrees}C with Pittsburgh No. 8 and DECS-17 Blind Canyon coals. From the complete reaction matrix containing the two coals and two resids, it was found that the influence of resids on coprocessing depended on the type of coal used; for example, under catalytic reaction conditions, the hexane solubles of Maya resid increased coal conversion of Pittsburgh No. 8 coal but decreased that of DECS-17. In order to observe the intrinsic behavior of resids during coprocessing, another resid, Manji, and another coal, Illinois No. 6, are being tested. These reactions were begun this quarter. The results obtained are reported in this report.
Date: July 1, 1995
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Role of the resid solvent in catalytic coprocessing with finely divided catalysts. Final report

Description: The role of the resid in coprocessing coal with petroleum resid has been investigated using model systems. The primary question being investigated is whether resid is participating in reactions with coal or if the resid is acting simply as a diluent. Since hydrogen transfer is an important mechanism by which solvent interacts with coal, hydrogen transfer between naphthenes, saturated alicyclic molecules, that represent resid and aromatic molecules that represent coal were examined in reactions with a high pressure H{sub 2} atmosphere that is typical of actual coprocessing. The model naphthene, perhydropyrene, was chosen as the donor species and the models, anthracene, phenanthrene, and benzophenone, were chosen as the acceptor species. Coprocessing reactions of coal with petroleum resid were performed to evaluate the effect of the chemistry of both constituents on coal conversion and the upgrading of the heavy resid. Three heavy resids, Maya, FHC-623 and Manji were used as the whole resid and as fractions that has been separates into hexane solubles and saturate fractions.
Date: January 1, 1996
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins. Quarterly report, October 1995--December 1995

Description: The goal of this research is to develop a methodology for analyzing the reactivity of cyclic olefins in situ in a high temperature and high pressure infrared cell. Cyclic olefins, such as 1,4,5,8-tetrahydronaphthalene (isotetralin) and 1,4,5,8,9,10-hexahydroanthracene (HHA), are highly reactive donor compounds that readily donate their hydrogen to coal and model acceptors when heated to temperatures of 200{degrees}C and above. These donors are active donors in the low severity liquefaction of coal at 350{degrees}C as shown in the research performed in this project. The infrared studies are being performed in a high temperature infrared cell that was obtained from AABSPEC. Modifications to that cell have been made and have been reported in previous progress reports. During this last quarter the useful temperature range of the high temperature infrared cell was extended to 230{degrees}C through the use of a high-boiling perfluorocarbon solvent. The solvent used was an Air Products and Chemicals Company proprietary product trade named Multifluor APF-240. Solubilities of aromatics and cyclic olefins were quite low in APF-240, usually less than 0.1 wt% at room temperature, but were found to be a strong function of temperature, increasing markedly when the mixtures were heated to 65{degrees}C. Spectra have been obtained of n-hexadecane and naphthalene at temperatures of 65, 100, 125, 150, 175, 200 and 230{degrees}C. This demonstration of the safe operation of the high temperature IR cell and the acquisition of spectra at elevated temperatures paves the way for kinetic studies of the hydrogen donor capability of isotetralin. A perfluoroether has been obtained from Dupont which should extend the useful temperature range of the high temperature IR cell to 350{degrees}C.
Date: December 31, 1995
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins. Quarterly report, January--March 1995

Description: The research performed during the quarter, January to March 1995, focused on two areas. The first area involved completing the writing of a manuscript based on research performed on this project concerning the mild acidic pretreatment of low rank coals and their liquefaction behavior in the presence of hydrogen donors with different reactivities. The manuscript was submitted for review to Energy and Fuels. A second manuscript was begun which discussed the research involving the hydrogen donation at low severity condition by hexahydroanthracene. The catalytic enhancement of hydrogen transfer by cyclic olefins was also examined. The data from this research was reexamined; it was decided that before writing the paper than the data should be reanalyzed. Therefore, this quarter was spent taking the raw data and reanalyzing the data, putting the solvent fractionation data on a solvent-free basis. The recalculated data and the calculational method is given as Part 1 in this report. The second area that was worked on this quarter was the high temperature infrared analysis of cyclic olefins. The work is ongoing and is currently involving a considerable amount of equipment and technique development. Part 2 is the discussion on the high temperature infrared analysis of cyclic olefins.
Date: September 1, 1995
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins

Description: Low severity coal liquefaction promoted by cyclic olefins offers a means of liquefying coal at low severity conditions. Lower temperature, 350[degrees]C, and lower hydrogen pressure, 500 psi, have been used to perform liquefaction reactions. The presence of the cyclic olefin, hexahydroanthracene, made a substantial difference in the conversion of Illinois No. 6 coal at these low severity conditions. The Researchperformed this quarter was a parametric evaluation of the effect of different parameters on the coal conversion and product distribution from coal. The effect of the parameters on product distribution from hexahydroanthracene was also determined. The work planned for next quarter includes combining the most effective parametric conditions for the low severity reactions and determining their effect. The second part ofthe research performed this quarter involved performing Fourier transform infrared (FTIR) spectroscopy using cyclic olefins. The objective of this study was to determine the feasibility of using FTIR and a heated cell to determine the reaction pathway that occurs in the hydrogen donation reactions from cyclic olefins. The progress made to date includes evaluating the FTIR spectra of cyclic olefins and their expected reaction products. This work is included in this progress report.
Date: January 1, 1992
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins

Description: The naphthalene hydrogenation performed thermally at 350 and 400[degrees]C showed no reactivity of the naphthalene. The Molyvan L catalyst precursor promoted a small amount of hydrogenation of naphthalene at 400[degrees]C as shown in Table 1. Reaction at the higher initial pressure of 1250 psi resulted in slightly more conversion of naplithalene and a higher production of tetralin but no decalin was observed. The naphthalene hydrogenation reactions with Molyvan L without sulfur yielded a slightly higher % HYD of naphthalene than did the reactions with sulfur. Likewise, the reactions with an initial hydrogen pressure of 1250 psi yielded a higher % HYD of naphthalene than did the reaction with 1000 psi, regardless of whether sulfur was present. The Molyvan 822 catalyst precursor was substantially more active at 400[degrees]C than at 350[degrees]C as presented in Table 2. The presence of sulfur also promoted the activity of Molyvan 822 as a catalyst. Tetralin was the product and was produced in substantial quantities at 400[degrees]C. Molyvan 822 was much more active for naphthalene hydrogenation than was Molyvan L under equivalent conditions. For example, at 400[degrees]C with sulfur the reactions with Molyvan 822 produced 33.5% HYD while Molyvan L yielded 1.8% HYD. With Molyvan L, the less active catalyst, the effect tile mode of agitation (vertical or horizontal) was minimal.
Date: January 1, 1992
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

The role of the resid solvent in co-processing with finely divided catalysts

Description: Goal this quarter was to evaluate the reactivity of an anthracene (H-deficient aromatic) and perhydropyrene (H-rich cycloalkane) system to determine if this system is the one desired for the parametric evaluation. Idea was to determine if hydrogen could be transferred from cycloalkane to aromatic in a hydrogen atmosphere, which is always present in coprocessing. This quarter's work established procedures for performing thermal and catalytic reactions without a solvent, and for analysis of reaction products. Individual thermal and catalytic reactions using anthracene and perhydropyrene were the primary reactions performed this quarter.
Date: January 1, 1992
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

The role of the resid solvent in co-processing with finely divided catalysts

Description: Primary purpose is to establish under thermal and catalytic reaction conditions whether hydrogen transfer occurred between cycloalkane type structures present in resids and aromatics present in coal and liquefied coal. Idea was to determine if hydrogen could be transferred from the cycloalkane to the atomatic in a hydrogen atmosphere, which is always present in co-processing. This document gives an extensive literature review, as well as a brief account of the experimental work. 3 tabs, 26 refs.
Date: March 23, 1993
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Improving the quality of deteriorated recycle solvents. Quarterly report, August 1982-November 1982

Description: The overall objective of this work is to identify reasons for solvent degeneration and to determine a feasible mechanism whereby coal-liquefaction processes can be modified to inhibit solvent degradation during the liquefaction process. In this work, the response in product distribution (or oil yield) to different pre-treatment methods was investigated. In related past works, solvent quality was based solely on the amount of standard coal conversion. In this work, solvent quality was also determined with the use of a standard product separation procedure. A brief discussion of related past works is followed up by a discussion of current work in the area of upgrading deteriorated recycle solvents. The effect of solvent pre-treatment on quality during thermal (non-catalytic) and catalytic liquefaction of coal was examined, and a comparison was made. In addition, the effect of the presence of typical compounds found in coal liquids (e.g. pyrene), during solvent pre-treatment, on solvent quality was also investigated. 2 references, 3 figures, 5 tables.
Date: January 1, 1982
Creator: Tarrer, A.R.; Guin, J.A. & Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins. Quarterly technical progress report, April--June 1996

Description: The goal of this research is to develop a methodology for analyzing the reactivity of cyclic olefins in situ in a high temperature and high pressure infrared cell. Cyclic olefins, such as 1,4,5,8-tetrahydronaphthalene (isotetralin) and 1,4,5,8,9,10-hexahydroanthracene (HHA), are highly reactive donor compounds that readily donate their hydrogen to coal and model acceptors when heated to temperatures of 200{degrees}C and above. These donors are active donors in the low severity liquefaction of coal at 350{degrees}C as shown in the research performed in this project. The infrared studies are being performed in a high temperature infrared cell that was obtained from AABSPEC. Modifications to that cell have been made and have been reported in previous progress reports.
Date: December 31, 1997
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins. Quarterly report, July--September 1996

Description: The goal of this research is to develop a methodology for analyzing the reactivity of cyclic olefins in situ in a high temperature and high pressure infrared cell. Cyclic olefins, such as 1,4,5,8-tetrahydronaphthalene (isotetralin) and 1,4,5,8,9,10-hexahydroanthracene (HHA), are highly reactive donor compounds that readily donate their hydrogen to coal and model acceptors when heated to temperatures of 200 C and above. These donors are active donors in the low severity liquefaction of coal at 350 C as shown in the research performed in this project. The infrared studies are being performed in a high temperature infrared cell that was obtained from AABSPEC. Modifications to that cell have been made and have been reported in previous progress reports. The useful temperature range of the high temperature infrared cell has been extended to 230 C through the use of a high-boiling perfluorocarbon solvent. High temperature infrared analyses have been performed using isotetralin, tetralin, naphthalene, 1,4-dihydronaphthalene and 1,2-dihydronaphthalene. Stability studies have shown that naphthalene was quite stable at temperatures up to 230 C, as were tetralin, decalin and 1,4-dihydronaphthalene. High temperature FTIR analysis of isotetralin and 1,2-dihydronaphthalene reacted at elevated temperatures forming tetralin and 1,4-dihydronaphthalene, respectively. The results of stability studies are reported.
Date: May 1, 1997
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Low severity coal liquefaction promoted by cyclic olefins. Quarterly report, October 1996--December 1996

Description: The goal of this research is to develop a methodology for analyzing the reactivity of cyclic olefins in situ in a high temperature and high pressure infrared cell. The reactivities of naphthalene, decalin, tetralin, isotetralin, 1,2-dihydronaphthalene and 1,4-dihydronaphthalene have been studied at 230{degrees}C under ambient pressure and under 500 psig blankets of both nitrogen and hydrogen.
Date: June 1, 1997
Creator: Curtis, C.W.
Partner: UNT Libraries Government Documents Department

Studies in coal liquefaction with application to the SRC and related processes. Final report, November 1978-September 1983

Description: The objective of this research program is to systematically investigate, characterize, and delineate the effects of changes in process operating conditions, equipment configuration, and nature of raw materials upon the kinetics, mechanism, and extent of coal dissolution, heteroatom removal, and hydrogenation in the SRC and closely related processes, for the purpose of providing an increased fundamental understanding of SRC process chemistry as well as guidelines and recommendations leading to economic and technical improvements in SRC technology. The program objectives were carried out in cooperation with the Souther Services' SRC pilot plant operation at Wilsonville, Alabama, and with the Rust Engineering subsidiary of Wheelabrator-Frye, Inc. The program is composed of the following 3 tasks: (1) mechanistic studies of coal particle dissolution; (2) catalysis by coal mineral matter; and (3) analytical support. A summary of the most important aspects of the work is presented in this report. Detailed results can be found by referring to the twenty quarterly reports and over thirty technical papers and presentations resulting from work under this contract.
Date: January 1, 1983
Creator: Tarrer, A. R.; Guin, J. A. & Curtis, C. W.
Partner: UNT Libraries Government Documents Department

Studies in coal liquefaction with application to the SRC and related processes. Quarterly report, May-July 1983

Description: This report examines liquid-phase adsorption as a possible method of studying the interactions between coal liquids and hydrotreating catalysts. The duel purposes of this work are to develop a method to determine specific surface areas of porous catalysts and to examine how compounds commonly found in coal liquids are adsorbed on hydrotreating catalysts. The liquid-phase adsorption studies were performed at room temperature in tubing bomb reactors. Adsorption isotherms obtained from these experiments were assumed to follow Langmuir-type behavior. Compounds used in these studies included PNA compounds, a basic nitrogen containing compound, and an acidic oxygen containing compound. Various commercial grade catalysts as well as presulfided CoMo/Al/sub 2/O/sub 3/ and presulfided iron oxide were used as adsorbents. Experiments have shown that quinoline, a basic nitrogen containing compound, appears to be an excellent compound for surface area determination via liquid-phase adsorption. Adsorption of compounds such as pyrene, a PNA compound, and phenol, an acidic oxygen containing compound, may be used to determine the relative areas of different types of sites on catalyst surfaces. The sensitivity of this liquid-phase adsorption technique was evaluated by adsorbing different solutes on various catalyst surfaces. This technique shows that the adsorptivity of different coal liquids is a distinct function of the individual properties of the adsorbate as well as the properties of adsorbent used. Comparison of the adsorption properties of these coal liquids on various adsorbents may give insights as to how they adsorb on hydrotreating catalysts, how they compete for the active catalyst sites, and what types of sites the adsorbed molecules occupy. 29 references, 37 figures, 41 tables.
Date: March 1, 1984
Creator: Tarrer, A. R.; Guin, J. A. & Curtis, C. W.
Partner: UNT Libraries Government Documents Department

Studies in coal liquefaction with application to the SRC and related processes. Quarterly report, November 1981-January 1982

Description: The concentration of hydroaromatics in a coal liquefaction solvent is regarded as a significant factor in the determination of solvent quality. An analytical method is described based on catalytic solvent dehydrogenation (CSD) for the measurement of transferable hydrogen, including hydroaromatic sources, in a solvent. The dehydrogenation of several model compounds in the presence of Pd/CaCO/sub 3/ was conducted under batch conditions. Hydroaromatics containing six-member rings were found to dehydrogenate effectively. Lesser degrees of dehydrogenation were found for alkyl-substituted aromatics and saturated compounds. CSD was applied to a series of hydrogenated creosote oils plus several light recycle oils. The normalized H/sub 2/ volumes obtained by CSD could be correlated with the coal-dissolution ability of the creosote oils. It was not possible to include the light recycle oils in the same correlation. /sup 13/C-NMR was used to measure the transferable hydrogen of selected hydrogenated creosote oils and light recycle oils. Values of transferable hydrogen determined by /sup 13/C-NMR were generally larger than the corresponding values obtained by CSD. A smooth correlation was found between coal conversion and transferable hydrogen as measured by /sup 13/C-NMR. The light recycle oils could not be fitted to the curve defined by the creosote oils. Minerals indigenous to coal provide an internal but weak source of catalytic activity during liquefaction reactions. A sensitive probe reaction, cyclohexene hydrogenation/isomerization, was used to compare the catalytic activity of several clay minerals, oxides used as catalyst supports, pyrite and liquefaction residue ashes.
Date: January 1, 1982
Creator: Tarrer, A.R.; Guin, J.A. & Curtis, C.W.
Partner: UNT Libraries Government Documents Department

The role of the resid solvent in coprocessing with finely divided catalysts. Quarterly report, July--September 1993

Description: The research performed this quarter involved evaluating the resid as the solvent in coprocessing. Since the objective of this research contract is to determine if the naphthenic portion of resids is able to transfer hydrogen to coal, the resid was fractionated in order to obtain different compositional fractions for liquefaction reactions. In order to evaluate different fractions of resids, the fractions must first be separated by liquid chromatography. The literature was surveyed as described below to determine the most feasible of effecting the separation. Methods used to analyze the fractions were also examined. On the basis of the information obtained, an experimental procedure was developed for separating the resid into fractions and then analyzing the fractions by Fourier transform infrared spectroscopy (FTIR) and by {sup 13}C nuclear magnetic resonance.
Date: December 31, 1993
Creator: Curtis, C. W.
Partner: UNT Libraries Government Documents Department