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Radiative properties of ash and slag

Description: Thermal radiation plays a key role in the operation and efficiency of combustion systems, accounting for over 90% of the heat transfer. The analysis of radiative heat transfer in coal-fired boilers, combustion chambers and other energy systems requires accounting for the effects of inorganic deposits on bounding surfaces and of entrained particulates, such as pulverized coal, char and fly-ash. These effects can be predicted; however, the accuracy in predicting the radiative properties of entrained particles (ash) and deposit layers (slag) is limited by inaccurate knowledge of the physical/chemical properties of the materials over a range of material temperatures and radiative wavelengths that is representative of conditions in practical combustion systems. The objective of this project is to make laboratory measurements of the radiative properties of extracted ash deposit samples. During this quarter, technique validation measurements were performed on several test samples. Technique validation has been achieved for infrared opaque and semi-transparent materials that exhibit a high degree of specular reflection (i.e. having a negligible diffuse reflectance component). Validation has not been achieved for non-specular reflecting surfaces, but work is progressing on modifying the present system to accommodate these materials.
Date: January 1, 1989
Creator: Solomon, P.R. & Markham, J.R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of retrograde reactions in direct liquefaction

Description: Most of the proposed processing schemes for improving liquefaction yields involve favoring bond-breaking and radical stabilization reactions over the retrograde reactions. The retrograde reactions are often encountered before liquefaction temperatures are reached. The objective of this program is to elucidate and model the retrograde reaction chemistry in direct coal liquefaction through the application of experimental techniques and theoretical models which have been successfully employed at Advanced Fuel Research (AFR) and SRI International (a subcontractor) to understand and predict coal reaction behavior. The study of retrograde reactions is being done using an integrated approach using extensive characterization of the liquefaction chemistry of three kinds of systems: (1) model polymers; (2) coal; and (3) modified coals.
Date: January 1, 1989
Creator: Serio, M.A.; Solomon, P.R.; Bassilakis, R. & Kroo, E.
Partner: UNT Libraries Government Documents Department

Fundamental studies of water pretreatment of coal

Description: The goals of this project are to gain an understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. For the achievement of these goals, coals, modified coals and model-polymers will be treated with water or steam. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g., acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases by GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment.
Date: January 1, 1991
Creator: Serio, M.A.; Kroo, E.; Solomon, P.R.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of retrograde reactions in direct liquefaction

Description: The overall objective of the program was to improve the understanding of retrograde reactions and their dependencies on coal rank and structure, and/or coal modifications and reaction conditions. Because retrograde reactions are competitive with bond breaking reactions, an understanding of both is required to shift the competition in favor of the latter. Related objectives were to clarify the conflicting observations reported in literature on such major topics as the role of oxygen groups in retrograde reactions and to provide a bridge from very fundamental studies on pure compounds to phenomenological studies on actual coal. This information was integrated into the FG-DVC model, which was improved and extended to the liquefaction context.
Date: December 17, 1991
Creator: Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of water pretreatment of coal

Description: During the seventh quarter, water pretreatment experiments were done at lower pressures (1000 psig), with early H{sub 2}O injection or continuous H{sub 2}O injection, and with demineralized coals. In addition, a set of blank experiments was done with all four coals in helium at the following conditions: 350{degrees}C; 4000 psig; 20 minutes. An additional experiment was done with the Zap lignite at atmospheric pressure. Helium was used instead of nitrogen since it can be obtained in highly pure grades. The purpose of the blank experiments is to determine how much of the water pretreatment process is a thermal and/or pressure effort. The residues from the standard water pretreatment experiments with Illinois and Pittsburgh coals were subjected to analysis by TG-FTIR, solvent extraction, solvent swelling, oxygen reactivity index and donor solvent liquefaction. The pyridine extractables were analyzed. With regard to liquefaction behavior, improvements in the yields of oils and toluene solubles are observed for selected Illinois and Pittsburgh coals at longer pretreatment times ({ge} 60 minutes).
Date: October 25, 1991
Creator: Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department

The dual role of oxygen functions in coal pretreatment and liquefaction: Crosslinking and cleavage reactions

Description: One objective of this program is to prepare polymer models having phenolic, carboxylic, and/or aryl ether groups considered to be important in low rank coals. In order to study the chemistry of these functional groups in a polymeric matrix, it is necessary that the polymer backbone itself should not be subject to cleavage under the reaction conditions. It is expected that poly(phenylene) would fulfill this requirement as a backbone, while providing simple mechanical routes for attaching other functional groups. During this reporting period, the synthesis of oligomeric species such as sexi(phenylene) and octa(phenylene) was explored. The procedure of Bamfield and Quam was followed, which involves heating a paste of bromoarenes, water, sodium formate and Pd/C. The reaction products turned out to be very insoluble and difficult to purify. The insolubility of these products makes them difficult to work with, and it is doubtful that we will be able to prepare well-characterized polymers in the 10,000 Da range. We are presently considering other polymeric substrates that might serve as the backbone. Pending the resolution of the polymeric substrate issue, the thermal behavior of the carboxyl and phenolic functions and the effect of ion-exchange will be studied using monomeric models. These studies will be needed to establish the baseline for considering the effect of the polymeric environment.
Date: January 1, 1991
Creator: Serio, M.A.; Kroo, E.; Teng, Hsisheng; Charpenay, S. & Solomon, P.R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of retrograde reactions in direct liquefaction

Description: Research on coal liquefaction continued. We have tried to get definitive structural information on the C-C-O polymers, (poly(4-allylphenol)) from a variety of analytical techniques. However, in all cases the results were not conclusive. In view of the need for a better characterization of the model polymers before drawing definitive conclusions from liquefaction of pyrolysis results, we have reexamined some of the previous analyses and have conducted further characterization of the C-C-O polymers by elemental analysis and FT-IR spectroscopy. Liquefaction experiments were repeated at 400{degree}C, 10 minutes for the three raw coals. For the Zap and Illinois coals, the results at 10 minutes were significantly different when compared to the first set of experiments. Since all of these experiments were done shortly before the heater elements failed in the Fluidized Sand Bath (FSB), it was thought that this may have been a contributing factor, since the reproducibility in the past has been quite good for the 30 minute experiments ({plus minus}3%). The FSB was rebuilt and liquefaction experiments were repeated for a second time at 400{degree}C, 10 minutes for the three raw coals. The results were now in general agreement with the results of the previous set. Work continued on using the AFR FG-DVC liquefaction model to predict the results of the experiments on coals and modified coals from this program. 3 refs., 3 figs.
Date: January 1, 1990
Creator: Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of water pretreatment of coal

Description: The goals of this project are to gain understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. For the achievement of these goals, coals, modified coals and model-polymers will be treated with water or stream. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g. acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases of GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment. 1 ref., 2 figs., 1 tab.
Date: January 1, 1990
Creator: Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of retrograde reactions in direct liquefaction. Topical report, September 30, 1988--September 30, 1989

Description: Most of the proposed processing schemes for improving liquefaction yields involve favoring bond-breaking and radical stabilization reactions over the retrograde reactions. The retrograde reactions are often encountered before liquefaction temperatures are reached. The objective of this program is to elucidate and model the retrograde reaction chemistry in direct coal liquefaction through the application of experimental techniques and theoretical models which have been successfully employed at Advanced Fuel Research (AFR) and SRI International (a subcontractor) to understand and predict coal reaction behavior. The study of retrograde reactions is being done using an integrated approach using extensive characterization of the liquefaction chemistry of three kinds of systems: (1) model polymers; (2) coal; and (3) modified coals.
Date: December 31, 1989
Creator: Serio, M. A.; Solomon, P. R.; Bassilakis, R. & Kroo, E.
Partner: UNT Libraries Government Documents Department

Feasibility study for an advanced coal fired heat exchanger/gas turbine topping cycle for a high efficiency power plant. Technical report, April 1, 1993--June 30, 1993

Description: Significant improvements in efficiency for the conversion of coal into electricity can be achieved by cycles which employ a high temperature recuperative gas turbine topping cycle. The objective of this project is the development of a new and proprietary concept for an externally fired gas turbine system. The chief advantage of this route is that the potential problems caused by the coal`s inorganic constituents are diverted from the high temperature rotating parts of the gas turbine to the high temperature stationary parts of a heat exchanger. The key technology issue is, then, the development of methods to fire a high temperature heat exchanger with coal in such a way that the potential damage from the inorganic constituents is minimized. The solution offered in this project is the design of a High Temperature Advanced Furnace (HITAF) with a Radiatively Enhanced, Aerodynamically Cleaned Heat-Exchanger (REACH-Exchanger). The REACH-Exchanger is fired by radiative and convective heat transfer from a moderately clean fuel stream and radiative heat transfer from the flame of a much larger uncleaned fuel stream. The approach is to utilize the best ceramic technology available for high temperature parts of the REACH-Exchanger and to shield the high temperature surfaces from interaction with coal minerals by employing clean combustion gases that sweep the tube surface exposed to the coal flame. In the proposed system, 80% of the energy to the REACH-Exchanger is supplied by radiation. The clean stream can be natural gas (base cycle) or volatile products of pyrolysis, low BTU gas from coal carbonization, or products of coal gasification (evolutionary cycle). The uncleaned stream can be coal or char.
Date: August 1, 1993
Creator: Solomon, P. R.; Zhao, Y.; Buggeln, R. C. & Shamroth, S. J.
Partner: UNT Libraries Government Documents Department

Feasibility study for an advanced coal fired heat exchanger/gas turbine topping cycle for a high efficiency power plant. Technical report, September 10, 1992--December 31, 1992

Description: The overall objective of this project is to prove the feasibility of AFR`s concepts for a high efficiency coal-fired generating plant using the REACH/Exchanger concept to power an externally fired gas turbine. It will provide a design of an advanced technology furnace/heat exchanger combination in which a ceramic heat exchanger is aerodynamically protected from the corrosive particle laden coal combustion products. The heat exchanger is fired by radiative and convective heat transfer from a moderately clean fuel stream and by radiative heat transfer from the flame of a much larger uncleaned fuel stream. In principle, 35% of the energy will be provided by the former and 65% by the later. The fluid mechanics in the furnace/heat exchanger are controlled so that the flow of the combustion products, from the moderately clean fuel stream, sweeps past the heat exchanger to prevent the contact of coal particles with the uncleaned stream.
Date: February 1, 1993
Creator: Solomon, P. R.; Zhao, Yuxin & Pines, D. S.
Partner: UNT Libraries Government Documents Department

Feasibility study for an advanced coal fired heat exchanger/gas turbine topping cycle for a high efficiency power plant. Technical report, January 1, 1993--March 31, 1993

Description: The overall objective of this project is to prove the feasibility of AFR`s concepts for a high efficiency coal-fired generating plant using the REACH/Exchanger concept to power an externally fired gas turbine. The computational REACH reactor was modeled with PCGC-2. The reactor geometry, inlet flow rates and configurations were investigated via modeling in order to get an optimum operation condition, with which a thorough coal and gas mixture and a required coal particle dispersion can both be achieved. This is to ensure the efficiencies of both coal combustion and aerodynamic cleaning. The aerodynamic cleaning effect of the tertiary air injection was modeled with CELMINT. Various injection schemes investigated show the dramatic impact of the tertiary air and the injection positions on the overall air flow pattern in the reactor which is one of the major influencing factors on the particle dispersion. It is clearly demonstrated that an optimum tertiary injection scheme with a reasonable flow rate is able to keep the heat exchange tubes from particle fouling.
Date: April 1, 1993
Creator: Solomon, P. R.; Zhao, Y.; Buggeln, R. C. & Shamroth, S. J.
Partner: UNT Libraries Government Documents Department

Radiative properties of ash and slag. Final report

Description: The objective of this program has been to make laboratory measurements of the radiative properties of ash and slag deposits that have been extracted from combustion devices. The program has resuited in measurements of radiative properlies of materials at high temperatures made by a technique employing a sample heatng deVice that is coupled to a FT-IR spectrometer to measure emission, directional-hemispherical transmission, and directional-hemispherical reflection of a sample. By this technique, the temperature at the measurement point and the spectral emittance (emissivity) of the surface are both obtained. These measurements are then related to the physical and chemical properties of the surface to determine what controls the radiative properlies. The measurements have shown that the physical state of a deposit (i.e. fused, sintered or packed particles) greatly influence the measured spectral emittance. The main accomplishments of the program are as follows: (1) Demonstration of measurement technique validation. (2) Measurements of spectral emittance for deposit samples as a function of temperature and morphology. (3) Accurate calculations of the optical properties of smooth and sintered surfaces based on the material`s complex Index of refraction and the surface morphology.
Date: October 1, 1990
Creator: Solomon, P. R.; Markham, J. R.; Best, P. E. & Yu, Zhen-Zhong
Partner: UNT Libraries Government Documents Department

The dual role of oxygen functions in coal pretreatment and liquefaction: Crosslinking and cleavage reactions. Second quarterly report, July 1, 1991--September 30, 1991

Description: One objective of this program is to prepare polymer models having phenolic, carboxylic, and/or aryl ether groups considered to be important in low rank coals. In order to study the chemistry of these functional groups in a polymeric matrix, it is necessary that the polymer backbone itself should not be subject to cleavage under the reaction conditions. It is expected that poly(phenylene) would fulfill this requirement as a backbone, while providing simple mechanical routes for attaching other functional groups. During this reporting period, the synthesis of oligomeric species such as sexi(phenylene) and octa(phenylene) was explored. The procedure of Bamfield and Quam was followed, which involves heating a paste of bromoarenes, water, sodium formate and Pd/C. The reaction products turned out to be very insoluble and difficult to purify. The insolubility of these products makes them difficult to work with, and it is doubtful that we will be able to prepare well-characterized polymers in the 10,000 Da range. We are presently considering other polymeric substrates that might serve as the backbone. Pending the resolution of the polymeric substrate issue, the thermal behavior of the carboxyl and phenolic functions and the effect of ion-exchange will be studied using monomeric models. These studies will be needed to establish the baseline for considering the effect of the polymeric environment.
Date: December 31, 1991
Creator: Serio, M. A.; Kroo, E.; Teng, Hsisheng; Charpenay, S. & Solomon, P. R.
Partner: UNT Libraries Government Documents Department

The dual role of oxygen functions in coal pretreatment and liquefaction: Crosslinking and cleavage reactions. Sixth quarterly report, July 1, 1992--September 30, 1992

Description: It is known from our results and the literature that the moisture is associated with cations in raw low rank coals. Consequently, an investigation was made to determine if the deleterious effects of cations could be mitigated by adding water to the donor solvent liquefaction system. Experiments were done with raw and demineralized Zap at three different temperature levels. At temperature near or below the critical temperature of water (374{degree}C), it appears that there is profound beneficial effect of added water for the raw coal. Conversely, there is a significant deleterious effect of added water for the demineralized coals. The ability of water to interact with cations and affect the course of the thermal decomposition behavior is consistent with results that have been observed in hydrothermal treatment of coal, which mimics the geological aging process in many respects.
Date: December 31, 1992
Creator: Serio, M. A.; Kroo, E.; Charpenay, S. & Solomon, P. R.
Partner: UNT Libraries Government Documents Department

The dual role of oxygen functions in coal pretreatment and liquefaction: Crosslinking and cleavage reactions. Seventh quarterly report, September 30, 1992--December 31, 1992

Description: The work during the past quarter under Task 2 has focused on the investigation of FT-IR methods for measuring carboxyl and phenolic functions. Fourier transform infrared (FT-IR) spectra of coal contain a wealth of information that can be utilized in the development of quantitative analysis routines based on least squares curvefitting. Because of the importance of the carboxylate groups in retrogressive reactions, recent efforts have focused on the C=O stretching region. Raw and modified coal samples (acid washed, demineralized, and cation exchanged) were analyzed in order to validate the proposed band assignments in the C=O stretching region. This parameter set differentiates free carbonyl (B2) and hydrogen-bonded carbonyl (B4) from carboxylic acid carbonyl (B3) and carboxylate (B7). One test of these assignments, which are based on literature data, is to plot B3 versus B7. This should be linear, assuming that the sum of the free carboxyl and carboxylate groups is constant and that the intensity of the overlapped aromatic ring band in B7 is also constant. This relationship was found to hold for a set of raw, acid washed, and acid washed/cation-exchanged Zap coals. The work under Task 3 has involved (1) completion of the synthesis of the -C-C-0- linked, methoxy substituted lignin-network polymer, -- C{sub 6}H{sub 3}(o-OMe)-O-CH{sub 2}CH{sub 2}]{sub {eta}} -- polymer, (2) Analysis of the polymer via depolymerization under pyrolysis-FIMS (Py-FIMS) conditions, and (3) testing of several routes to selective cleavage of the O-Methyl bond so that the relative crosslinking tendencies of the methylated and unmethylated versions of the polymer could be determined.
Date: December 31, 1992
Creator: Serio, M. A.; Kroo, E.; Charpenay, S. & Solomon, P. R.
Partner: UNT Libraries Government Documents Department

Radiative properties of ash and slag. Sixth quarterly report, November 1, 1988--January 31, 1989

Description: Thermal radiation plays a key role in the operation and efficiency of combustion systems, accounting for over 90% of the heat transfer. The analysis of radiative heat transfer in coal-fired boilers, combustion chambers and other energy systems requires accounting for the effects of inorganic deposits on bounding surfaces and of entrained particulates, such as pulverized coal, char and fly-ash. These effects can be predicted; however, the accuracy in predicting the radiative properties of entrained particles (ash) and deposit layers (slag) is limited by inaccurate knowledge of the physical/chemical properties of the materials over a range of material temperatures and radiative wavelengths that is representative of conditions in practical combustion systems. The objective of this project is to make laboratory measurements of the radiative properties of extracted ash deposit samples. During this quarter, technique validation measurements were performed on several test samples. Technique validation has been achieved for infrared opaque and semi-transparent materials that exhibit a high degree of specular reflection (i.e. having a negligible diffuse reflectance component). Validation has not been achieved for non-specular reflecting surfaces, but work is progressing on modifying the present system to accommodate these materials.
Date: December 31, 1989
Creator: Solomon, P. R. & Markham, J. R.
Partner: UNT Libraries Government Documents Department

Coal liquefaction process streams characterization and evaluation: FT-IR methods for characterization of coal liquefaction products

Description: This study was designed to demonstrate the use of two FTIR techniques for the analysis of direct coal liquefaction process-derived materials. The two methods were quantitative FTIR analysis and themogravimetric (TG) analysis with FTIR analysis of evolved products (TG-FTIR). The quantitative FTIR analyses of both whole resids and THF-soluble resids provided quantitation of total hydrogen, aliphatic and aromatic hydrogen, total carbon, total oxygen, hydroxyl and etheric oxygen, and ash contents. The FTIR results were usually in agreement with values derived by other, more conventional methods. However, the accuracies of specific measurements, in comparisons with results from conventional methods, ranged from good to poor. The TG-FTIR method provided approximate analyses of coals and resids. The data provided included the time dependent evolution profiles of the volatile species and the elemental composition of the char. Reproducible data of gaseous species and pyrolysis tar yields for whole resid samples larger than 10 mg were obtainable. The yields and evolution profiles of certain volatiles (tar, CO, and methane) provided structural information on the samples. There were some experimental and interpretational difficulties associated with both techniques. Optimization of the curve-resolving routine for coal-liquefaction samples would improve the quantitative FTIR accuracy. Aerosol formation limited the full application of the TG-FTIR technique with the THF-soluble resid samples. At this time, further development of these analytical methods as process development tools will be required before their use for that purpose can be recommended. The use of FTIR as an on-line analytical technique for coal liquefaction process streams requires demonstration before it can be recommended; however, such a demonstration may be warranted.
Date: April 1, 1992
Creator: Serio, M. A.; Teng, H.; Bassilakis, R. & Solomon, P. R.
Partner: UNT Libraries Government Documents Department

Radiative properties of ash and slag. Ninth quarterly report, October 1, 1989--December 31, 1989

Description: Thermal radiation plays a key role in the operation and efficiency of combustion systems, accounting for over 90% of the heat transfer. The analysis of radiative heat transfer in coal-fired boilers, combustion chambers and other energy systems requires accounting for the effects of inorganic deposits on bounding surfaces and of entrained particulates, such as pulverized coal, char, and fly-ash. These effects can be predicted; however, the accuracy in predicting the radiative properties of entrained pyrolysis (ash) and deposit layers (slag) is limited by inaccurate knowledge of the physical/chemical properties of the materials over a range of material temperatures and radiative wavelengths that is representative of conditions in practical combustion systems. The objective of this project is to make laboratory measurements of the radiative properties of extracted ash and slag deposit samples.
Date: March 1, 1990
Creator: Solomon, P. R. & Markham, J. R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of water pretreatment of coal

Description: The goals of this project are to gain understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. Coals, modified coals and model-polymers will be treated with water or steam. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g. acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases by GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment. 3 figs., 3 tabs.
Date: January 1, 1990
Creator: Serio, M.A.; Solomon, P.R.; Kroo, E.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department

Measurement and Modeling of Advanced Coal Conversion Processes

Description: The objectives of this proposed study are to establish the mechanisms and rates of basic steps in coal conversion processes, to integrate and incorporate this information into comprehensive computer models for coal conversion processes, to evaluate these models and to apply them to gasification, mild gasification and combustion in heat engines. This report describes progress during twenty second quarter of the program. Specifically, the paper discusses progress in three task areas: (1) Submodel development and evaluation: coal to char chemistry submodel; fundamental high-pressure reaction rate data; secondary reaction of pyrolysis product and burnout submodels; ash physics and chemistry submodel; large particle submodels; large char particle oxidation at high pressures; and SO[sub x]-NO[sub x] submodel development and evaluation; (2) Comprehensive model development and evaluation: integration of advanced submodels into entrained-flow code, with evaluation and documentation; comprehensive fixed-bed modeling review, development evaluation and implementation; and generalized fuels feedstock submodel; and (3) Application of integrated codes: application of generalized pulverized coal comprehensive code and application of fixed-bed code.
Date: January 1, 1992
Creator: Solomon, P. R.; Serio, M. A.; Hamblen, D. G.; Smoot, L. D. & Brewster, B. S.
Partner: UNT Libraries Government Documents Department

The dual role of oxygen functions in coal pretreatment and liquefaction: Crosslinking and cleavage reactions. Fifth quarterly report, April 1, 1992--June 30, 1992

Description: Preparation of ion-exchanged (including barium, calcium and potassium) demineralized Zap and Wyodak has been completed. Both vacuum dried and moist samples were prepared, using procedures described previously. The modified samples were subjected to functional group analysis as KBr pellets with FT-IR, and programmed pyrolysis analysis with TG-FTIR. Liquefaction experiments of these samples were also performed and products were analyzed. The data show that both the pyrolytic tar and liquefaction yields decrease with the extent of ion-exchange, i.e., in the order of (demineralized) > (ion-exchanged at pH 8) > (ion-exchanged at pH 12.5). For the pyrolysis of vacuum dried samples, the tar yield was higher for the potassium-exchanged coals than the calcium and barium-exchanged samples, suggesting that bivalent cations tighten the coal structure by cross-linking coal fragments and make it more difficult for tar molecules to escape. The liquefaction results show that the potassium-exchanged samples have higher liquefaction yields (especially asphaltenes) than for the barium- and calcium-exchanged samples. This can probably be attributed to the same reason for the high pyrolytic tar yield, i.e., that bivalent cations can serve as a cross-linking agents to tighten the coal structure. Remoisturization of vacuum dried Zap and Wyodak was done in the attempt to understand if moisture uptake for low rank coals is a reversible process and to see if moisture influences the role of the cations. Preliminary results show that the moisture content can reach that of the raw samples by remoisturization for Zap, but not for Wyodak. Furthermore, the chemical structure of the coal samples seems to have been changed by remoisturization, since different C0{sub 2} evolution behaviors were observed.
Date: December 1, 1992
Creator: Serio, M. A.; Kroo, E.; Teng, H.; Charpenay, S. & Solomon, P. R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of water pretreatment of coal. Second annual report, October 1, 1990--September 30, 1991

Description: The goals of this project are to gain an understanding of the chemistry of water or steam coal pretreatments and to assess the importance of such pretreatments on subsequent coal liquefaction. For the achievement of these goals, coals, modified coals and model-polymers will be treated with water or steam. This study will include three coals, five modifications (dried, demineralized, ion-exchanged, Ca-loaded, Ba-loaded), three polymers and two polymer modifications (e.g., acid chlorides, amides). Experiments will be performed to investigate both conventional steam pretreatment and the possibility of using the CO/H{sub 2}O system of Ross and coworkers as a pretreatment method. The main experimental variables will be sample type and temperature. Detailed characterization of the gas, liquid and solid products from the pretreatment stage will be done. This will include analysis of gases by GC or FT-IR, liquids by capillary GC, FT-IR and FIMS, and residues by solvent swelling, solvent extraction, and elemental analysis. Selected residues will also be evaluated by a standard liquefaction test. Analysis of the raw coals and pretreatment samples will be performed using the above techniques to study changes in the crosslinking, donatable hydrogen, heteroatom composition, evolved gases, functional group composition, extraction yields, molecular weight distributions, etc. Standard tubing bomb liquefaction tests will be used to determine the effect of pretreatment on coal reactivity toward coal liquefaction. A previously developed model for coal liquefaction, the FG-DVC liquefaction model, will be used (after appropriate modifications) to model the physics and chemistry of water pretreatment.
Date: December 31, 1991
Creator: Serio, M. A.; Kroo, E.; Solomon, P. R.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department

Fundamental studies of water pretreatment of coal. Seventh quarterly report, April 1, 1991--June 30, 1991

Description: During the seventh quarter, water pretreatment experiments were done at lower pressures (1000 psig), with early H{sub 2}O injection or continuous H{sub 2}O injection, and with demineralized coals. In addition, a set of blank experiments was done with all four coals in helium at the following conditions: 350{degrees}C; 4000 psig; 20 minutes. An additional experiment was done with the Zap lignite at atmospheric pressure. Helium was used instead of nitrogen since it can be obtained in highly pure grades. The purpose of the blank experiments is to determine how much of the water pretreatment process is a thermal and/or pressure effort. The residues from the standard water pretreatment experiments with Illinois and Pittsburgh coals were subjected to analysis by TG-FTIR, solvent extraction, solvent swelling, oxygen reactivity index and donor solvent liquefaction. The pyridine extractables were analyzed. With regard to liquefaction behavior, improvements in the yields of oils and toluene solubles are observed for selected Illinois and Pittsburgh coals at longer pretreatment times ({ge} 60 minutes).
Date: October 25, 1991
Creator: Serio, M. A.; Solomon, P. R.; Kroo, E.; Charpenay, S. & Bassilakis, R.
Partner: UNT Libraries Government Documents Department