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At least 19 records

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NASA NTRS1982

Coal desulfurization by chlorinolysis production and combustion test evaluation of product coals

Laboratory-scale screening tests were carried out on coal from Harrison County, Ohio to establish chlorination and hydrodesulfurization conditions for the batch reactor production of chlorinolysis and chlorinolysis-hydrodesulfurized coals. In addition, three bituminous coals, were treated on the lab scale by the chlorinolysis process to provide 39 to 62% desulfurization. Two bituminous coals and one subbituminous coal were then produced in 11 to 15 pound lots as chlorinolysis and hydrodesulfurized coals. The chlorinolysis coals had a desulfurization of 29-69%, reductions in voltatiles and hydrogen. Hydrodesulfurization provided a much greater desulfurization (56-86%), reductions in volatiles and hydrogen. The three coals were combustion tested in the Penn State ""plane flame furnace'' to determine ignition and burning characteristics. All three coals burned well to completion as: raw coals, chlorinolysis processed coals, and hydrodesulfurized coals. The hydrodesulfurized coals experienced greater ignition delays and reduced burning rates than the other coals because of the reduced volatile content. It is thought that the increased open pore volume in the desulfurized-devolatilized coals compensates in part for the decreased volatiles effect on ignition and burning.

Kalvinskas, J. J.↗

NASA NTRS1978

Remote sensing of strippable coal reserves and mine inventory in part of the Warrior Coal Field in Alabama

Methods by which estimates of the remaining reserves of strippable coal in Alabama could be made were developed. Information acquired from NASA's Earth Resources Office was used to analyze and map existing surface mines in a four-quadrangle area in west central Alabama. Using this information and traditional methods for mapping coal reserves, an estimate of remaining strippable reserves was derived. Techniques for the computer analysis of remotely sensed data and other types of available coal data were developed to produce an estimate of strippable coal reserves for a second four-quadrangle area. Both areas lie in the Warrior coal field, the most prolific and active of Alabama's coal fields. They were chosen because of the amount and type of coal mining in the area, their location relative to urban areas, and the amount and availability of base data necessary for this type of study.

Joiner, T. J.↗

NASA NTRS1978

New method of feeding coal - Continuous extrusion of fully plastic coal

Continuous feeding of coal in a compressing screw extruder is described as a method of introducing coal into pressurized systems. The method utilizes the property of many bituminous coals of softening at temperatures from 350 to 400 C. Coal is then fed much in the manner of common thermoplastics, using screw extruders. Preliminary results show that coals can be extruded at rates of about 3.3 kg/MJ, similar to those for plastics.

Ryason, P. R.↗

NASA NTRS1978

Performance and economics of advanced energy conversion systems for coal and coal-derived fuels

The desire to establish an efficient Energy Conversion System to utilize the fossil fuel of the future - coal - has produced many candidate systems. A comparative technical/economic evaluation was performed on the seven most attractive advanced energy conversion systems. The evaluation maintains a cycle-to-cycle consistency in both performance and economic projections. The technical information base can be employed to make program decisions regarding the most attractive concept. A reference steam power plant was analyzed to the same detail and, under the same ground rules, was used as a comparison base. The power plants were all designed to utilize coal or coal-derived fuels and were targeted to meet an environmental standard. The systems evaluated were two advanced steam systems, a potassium topping cycle, a closed cycle helium system, two open cycle gas turbine combined cycles, and an open cycle MHD system.

Corman, J. C.↗

NASA NTRS1980

Coal gasification systems engineering and analysis. Appendix A: Coal gasification catalog

The scope of work in preparing the Coal Gasification Data Catalog included the following subtasks: (1) candidate system subsystem definition, (2) raw materials analysis, (3) market analysis for by-products, (4) alternate products analysis, (5) preliminary integrated facility requirements. Definition of candidate systems/subsystems includes the identity of and alternates for each process unit, raw material requirements, and the cost and design drivers for each process design.

Source record↗

NASA NTRS1981

Applications of polymer extrusion technology to coal processing

Upon heating, many of the middle-aged bituminous coals exhibit a plasticity very similar to polyethylene for a few minutes. Plastic coal can be extruded, pelletized or molded using common plastics technology and equipment. Investigations concerning the plastic state of coals are conducted with the objective to develop techniques which will make useful commercial applications of this property possible. Experiments which show the characteristics of plastic-state coal are discussed, and problems related to a continuous extrusion of coal are considered. Probably the most significant difference between the continuous extrusion of coal and the extrusion of a thermoplastic polymer is that volatiles are continuously being released from the coal. Attention is given to aspects of dragflow, solids feeding, and melt pumping. Application potentials for plastic coal extrusion might be related to coal gasification, direct liquefaction, and coal combustion.

Lewis, D. W.↗

NASA NTRS1990

Calcium impregnation of coal enriched in CO.sub.2 using high-pressure techniques

Methods are described for impregnating coal with calcium carbonate by utilizing an aqueous phase ionic reaction between calcium acetate, calcium hydroxide, and water with CO.sub.2 contained within the coal. The coal is enriched in CO.sub.2 by contacting it with CO.sub.2 at high pressure, in either a continuous or pulsed mode. The inclusion of CO.sub.2 in the coal during the process does not involve evacuating the coal and subsequently absorbing CO.sub.2 onto the coal as in prior methods. Rather, the coal is treated with carbon dioxide at high pressure in a practical and viable approach. The impregnation of coal by calcium compounds not only reduces sulfur emissions by effectively tying up the sulfur as calcium sulfide or sulfate, but also increases the gasification or combustion rate. The invention also encompasses the use of other Group IIA elements, as well as the coal products resulting from the methods of treatment described.

Sharma, Pramod K.↗

NASA NTRS1978

Continuous extrusion of coal

A feeding method for use with bituminous coals that exhibit plasticity at elevated temperatures is described and demonstrated on a small screw extruder previously used to extrude polyethylene. A metered feed of coal heated to a temperature just below that of incipient caking (approximately 450 C) is used. Modifications to the extruder consisting of ceramic band heaters, auxiliary cooling coils on the thrust bearing and special quick opening dies are detailed. Coals successfully extruded include high volatile A bituminous coals, high volatile B bituminous coals, a high volatile C bituminous coal and a coal with high ash content. The computer program, EXTRUD, used to simulate the extruder is described. Predicted power consumption exhibits 30% scatter, which is explained by the sensitivity of the coal friction coefficient to temperature profiles. Detailed analysis reveals some discrepancies in the program that need to be resolved.

England, C.↗

NASA NTRS1980

Continuous coal processing method

A coal pump is provided in which solid coal is heated in the barrel of an extruder under pressure to a temperature at which the coal assumes plastic properties. The coal is continuously extruded, without static zones, using, for example, screw extrusion preferably without venting through a reduced diameter die to form a dispersed spray. As a result, the dispersed coal may be continuously injected into vessels or combustors at any pressure up to the maximum pressure developed in the extrusion device. The coal may be premixed with other materials such as desulfurization aids or reducible metal ores so that reactions occur, during or after conversion to its plastic state. Alternatively, the coal may be processed and caused to react after extrusion, through the die, with, for example, liquid oxidizers, whereby a coal reactor is provided.

Ryason, P. R.↗

NASA NTRS1992

Diterpanes, triterpanes, steranes, and aromatic hydrocarbons in natural bitumens and pyrolysates from different humic coals

Data are presented on the distribution of diterpanes, triterpanes, steranes, and aromatic hydrocarbons in the natural bitumens extracted from unheated coals identified as Rocky Mountain coal (RMC), Australian Gippsland Latrobe Eocene coal (GEC), Australian Gippsland Latrobe Cretaceous coal (GCC), and Texas Wilcox lignite (WL), as well as from pyrolysates obtained from heating of these coals. It was found that pentacyclic triterpanes are dominant in GEC, GCC, and WL, whereas diterpanes strongly predominate in the bitumen of RMC, indicating that resin is a more important constituent of RMC than of the other coals and that it releases the diterpenoids at an early stage of diagenesis. It was also found that the composition of diterpanes is different among these coals and that the distributions of sterane and triterpane in the natural bitumen of coals are very different from those of pyrolysates.

Lu, Shan-Tan↗

NASA NTRS1976

Study to determine dielectric properties of sandstone, shale, coal, and slate

Triplicate dielectric constant and loss tangent measurements on samples of sandstone, shale, coal, and slate were performed. Each of the three necessary configurations of the coal material was sampled to obtain measurements, with each sample machined parallel to the coal layering orientation. The coal samples were machined perpendicular to the coal layering and measured. They were conditioned at 100% humidity and at room temperature and remeasured; then conditioned in an elevated environment, and remeasured for dielectric properties. The coal data appear to remain relatively constant over the microwave frequency region. At the Ghz frequencies, the relative dielectric constant of coal is slightly higher for the E-field parallel to the layers than for the perpendicular case.

Bassett, H. L.↗

NASA NTRS1981

Coal desulfurization by low temperature chlorinolysis, phase 3

Laboratory scale, bench scale batch reactor, and minipilot plant tests were conducted on 22 bituminous, subbituminous, and lignite coals. Chemical pretreatment and post treatment of coals relative to the chlorination were tried as a means of enhancing desulfurization by the chlorinolysis process. Elevated temperature (500-700 C) hydrogen treatment of chlorinolysis-processed coal at atmospheric pressure was found to substantially increase coal desulfurization up to 90 percent. Sulfur forms, proximate and ultimate analyses of the processed coal are included. Minipilot plant operation indicates that the continuous flow reactor provides coal desulfurization results comparable to those obtained in the batch reactor. Seven runs were conducted at coal feed rates of 1.5 to 8.8 kg per hour using water and methylchloroform solvents, gaseous chlorine feed of 3 to 31.4 SCFH at 21 to 70 C, and atmospheric pressure for retention times of 20 to 120 minutes.

Kalvinskas, J. J.↗

NASA NTRS1982

A study of the United States coal resources

Geologically significant coal resources were identified. Statistically controlled tonnage estimates for each resource type were prepared. Particular emphasis was placed on the identification and description of coals in terms of seam thickness, inclination, depth of cover, discontinuities caused by faulting and igneous intrusion, and occurrence as isolated or multiseam deposits. The national resource was organized into six major coal provinces: the Appalachian Plateau, the Interior Basins, the Gulf Coastal Plain, the Rocky Mountain Basins, the High Plains, and North Alaska. Each basin within a province was blocked into subareas of homogeneous coal thickness. Total coal tonnage for a subarea was estimated from an analysis of the cumulative coal thickness derived from borehole or surface section records and subsequently categorized in terms of seam thickness, dip, overburden, multiseam proportions, coal quality, and tonnage impacted by severe faulting and igneous intrusions. Confidence intervals were calculated for both subarea and basin tonnage estimates.

Ferm, J. C.↗

NASA NTRS1987

Tribological properties of coal slurries

A pin-on-disk tribometer was used to study the tribological properties of methyl alcohol-coal slurries. Friction coefficients, steel pin wear rates and wear surface morphological studies were conducted on AISI 440C HT and M-50 bearing steels which were slid dry and in solutions of methyl alcohol, methyl alcohol-fine coal particles, and methyl alcohol-fine coal particles-flocking additive. The latter was an oil derived from coal and originally intended to be added to the coal slurry to improve the sedimentation and rheology properties. The results of this study indicated that the addition of the flocking additive to the coal slurry markedly improved the tribological properties, especially wear. In addition, the type of steel was found to be very important in determining the type of wear that took place. Cracks and pits were found on the M-50 steel pin wear surfaces that slid in the coal slurries while 440C HT steel pins showed none.

Fusaro, Robert L.↗

NASA NTRS1988

Mechanisms of elevated-temperature deformation in the B2 aluminides NiAl and CoAl

A strain rate change technique, developed previously for distinguishing between pure-metal and alloy-type creep behavior, was used to study the elevated-temperature deformation behavior of the intermetallic compounds NiAl and CoAl. Tests on NiAl were conducted at temperatures between 1100 and 1300 K while tests on CoAl were performed at temperatures ranging from 1200 to 1400 K. NiAl exhibits pure-metal type behavior over the entire temperature range studied. CoAl, however, undergoes a transition from pure-metal to alloy-type deformation behavior as the temperature is decreased from 1400 to 1200 K. Slip appears to be inherently more difficult in CoAl than in NiAl, with lattice friction effects limiting the mobility of dislocations at a much higher tmeperature in CoAl than in NiAl. The superior strength of CoAl at elevated temperatures may, therefore, be related to a greater lattice friction strengthening effect in CoAl than in NiAl.

Yaney, D. L.↗

NASA NTRS1975

The manufacture of hydrogen from coal

The conversion of coal to hydrogen is studied from the viewpoint of overall plant efficiency for three different processes: suspension gasification, fluidized-bed gasification, and fluidized steam-iron process. The basic principles of these processes are reviewed, and total energy requirements are estimated and complete energy balances are made for each process, on the assumption that each model plant is self-contained, with no power imported. Overall plant efficiencies for conversion of coal to major gaseous products plus by-products were determined to be: suspension gasification - 57.0%, fluidized-bed gasification - 66.4%, fluidized steam-iron process - 62.6%. Similar results are presented for methane liquefaction from coal using a process design based on hydrogasification, and it is found that conversion of coal to pipeline methane is much more efficient and less expensive than hydrogen conversion if a portion of the coal is converted to synthesis gas and this gas is used to hydrogenate more coal to methane.

Tsaros, C. L.↗

NASA NTRS1977

Borehole hydraulic coal mining system analysis

The borehole hydraulic coal mining system accesses the coal seam through a hole drilled in the overburden. The mining device is lowered through the hole into the coal seam where it fragments the coal with high pressure water jets which pump it to the surface as a slurry by a jet pump located in the center of the mining device. The coal slurry is then injected into a pipeline for transport to the preparation plant. The system was analyzed for performance in the thick, shallow coal seams of Wyoming, and the steeply pitching seams of western Colorado. Considered were all the aspects of the mining operation for a 20-year mine life, producing 2,640,000 tons/yr. Effects on the environment and the cost of restoration, as well as concern for health and safety, were studied. Assumptions for design of the mine, the analytical method, and results of the analysis are detailed.

Floyd, E. L.↗

NASA NTRS1977

Development of coal-feeding systems at the Morgantown Energy Research Center

Systems for feeding crushed and pulverized coal into coal conversion reactor vessels are described. Pneumatic methods for feeding pulverized coal, slurry feeders, and coal pumps, methods for steam pickup, and a method for drying a water-coal slurry in a steam fluidized bed subsequent to feeding the coal into a reactor vessel are included.

Hobday, J. M.↗