Showing papers on "Coal published in 1974"

Method and apparatus for in situ gasification of coal and the commercial products derived therefrom

Abstract: The process of the invention includes the concept of igniting a coal formation in situ with hot granular material and subsequently allowing the material to flow into the burning coal formation to serve as a propping agent in the event of a cave-in. Gasifying agents are injected into the formation in an alternating pattern to alternately oxidize and reduce the coal environment to optimize the BTU content of the recovered gas. Further, a heat receptive liquid is circulated through the casing in the well connecting the coal formation to the surface to strip the sensible heat from the produced gases so that the heat can be used for useful purposes apart from the produced gas. The apparatus of the invention includes a casing in the well bore which has a plurality of vertically spaced dividers each having a passage therethrough so that a heat receptive fluid can be passed between dividers in a vertical descent through the casing and during such descent strip sensible heat from the produced gas before being brought back to the surface. Hot granular material is placed in the well in contact with the coal formation to ignite the formation and to flow into cavities formed in the formation during the burning thereof to serve as a propping agent.

Fossil plants and coal: patterns of change in pennsylvanian coal swamps of the illinois basin.

Abstract: Coal palynology and studies of petrified peat indicate major changes in coal-swamp floras and the botanical constituents of coal throughout Pennsylvanian time. The changes are the result of broad climatic shifts and local environmental factors. The most striking is the change from a lycopod-dominated flora to one in which tree ferns were the major element. This change occurred at the Desmoinesian-Missourian (Westphalian-Stephanian) boundary and is probably multicontinental in scope.

Underground gasification of coal

Abstract: There is disclosed a method for the gasification of coal in situ which comprises drilling at least one well or borehole from the earth's surface so that the well or borehole enters the coalbed or seam horizontally and intersects the coalbed in a direction normal to its major natural fracture system, initiating burning of the coal with the introduction of a combustion-supporting gas such as air to convert the coal in situ to a heating gas of relatively high calorific value and recovering the gas. In a further embodiment the recovered gas may be used to drive one or more generators for the production of electricity.

Fluid bed coal gasification

Abstract: A process and apparatus for gasifying coal to produce carbon monoxide and hydrogen in which a first stream of coal is burned without bed formation in a combustion zone in the presence of water under oxidation conditions to produce gases containing carbon dioxide and steam. A second stream of coal is maintained as a fluid bed in a separate gasifier zone by upflowing carbon dioxide and steam from the combustion zone while being gasified under reducing conditions to produce carbon monoxide and hydrogen. Char produced in the fluid bed is elutriated overhead and material in the fluid bed is prevented from direct entry into the combustion zone. The ratio of carbonaceous material to ash in the char removed overhead is lower than the average ratio of carbonaceous material to ash in the solids in the fluid bed.

Temperature distribution inside a burning cigarette

Abstract: THE study reported here has been undertaken to resolve the large discrepancies between reports of the temperature distribution in the combustion coal of a cigarette. Studies using bare thermocouples (refs 1–4 and R. G. Hook, paper presented at Twentieth Tobacco Chemists' Conference, Winston-Salem, North Carolina, November 1966) indicate that the highest temperatures occur on the central axis of the coal (the actual reported values vary considerably but are usually in the range 800–900° C during a puff, 700–800° C during the natural smoulder between puffs, and 800–850° C under steady state continuous draw conditions). Under all smoking regimes, the thermocouple-measured temperature decreases by up to 300° C along a radius from the maximum central temperature to the periphery of the coal, although one thermocouple study2 has reported the occurrence of occasional peripheral hot spots, with temperatures higher than the centre of the coal. (Ref. 2 contains a comprehensive compilation of more than forty studies of temperature measurements inside burning cigarettes prior to 1968.) In contrast, temperature measurements by X-ray observations of the melting of small metal particles placed within the cigarette5 indicate that the highest temperatures (900° C) occur at the periphery of the coal. Furthermore, measurements of the coal's surface temperature by radiation methods (ref. 5 and A. T. Lendvay, F. M. Watson III, and T. S. Laszlo, paper presented at the CORESTA/Tobacco Chemists' Joint Conference, Williamsburg, Virginia, October 1972) have recorded temperatures of about 850–920° C during a puff, 700° C (below the surface ash) during smoulder, and short-lived hot spots on the coal's surface as high as 1200° C (ref. 5).

Process for recovering upgraded products from coal

Abstract: A process for recovering and upgrading products from solid coal by contacting the coal with a dense-water-containing fluid at a temperature in the range of from about 600° F. to about 900° F. in the absence of externally supplied hydrogen or other reducing gas and in the presence of a sulfur-resistant catalyst.

Underground coal gasification.

Abstract: Overview Underground coal gasification (UCG) converts coal in place (underground) into a gaseous product, commonly known as synthesis gas or syngas, through the same chemical reactions that occur in conventional above-ground gasification plants. It has many of the advantages of conventional gasification with respect to flexibility in commercial use, but has a potentially lower cost and a superior environmental profile. UCG could increase coal resources available for utilization enormously by gasifying otherwise unmineable deep or thin coal seams. UCG may have a cost advantage over other coal conversion technologies. This advantage may be particularly relevant to the area of carbon dioxide capture and storage (CCS). As a result, UCG may not only provide an important avenue for low carbon use of coal in the U.S., but also eventually in rapidly developing economies. UCG technology was first developed in the former Soviet Union (FSU) in the 1920s. The U.S. and Europe also conducted several tests in the 1970s and 1980s. In the 1990s, China began UCG research and development and is continuing with this effort. UCG is currently experiencing a resurgence with the development of a handful of initial commercial start ups in the last decade, as well as some successful pilot projects. However, a significant research and development effort is needed to fully commercialize the technology and make it available for wide-scale use. History Between 1974 and 1989, the U.S. was the site of major research and deployment efforts in UCG. This was largely driven by the OPEC oil embargos and increasing oil prices, and ended effectively with the 1986 drop in oil prices. During this time, there were 33 UCG pilots in Wyoming, Texas, Alabama, West Virginia, and Washington. These plants were laboratories for major technology developments and validation of cavity growth and gasification models. The Department of Energy (DOE) sponsored much of this research, and Lawrence Livermore National Lab was a major participant, managing 50% of the pilot plants. The FSU was the first nation to initiate a national program of UCG research and development, in 1928. Underground experiments had begun by 1933 in parallel with the experimental and theoretical programs. Commercial-scale production of syngas was achieved at numerous locations and for long periods of time, most notably at Angren, Uzbekistan. The Angren mine began production in 1959 and still has UCG technology in place to produce 18 billion cubic feet of gas for the Angren power station. …

Apparatus for determining high pressure coal‐hydrogen reaction kinetics under rapid heating conditions

Abstract: A simple and relatively inexpensive method is described for measuring the rate and extent of the reaction of coal with hydrogen under conditions of commercial interest. A thin layer of pulverized coal is supported on an electrically heated metal screen strip capable of initial heating rates of 600–12 000°C/sec followed by extended time at final temperatures of 400–200°C. The device is enclosed in a vessel designed for hydrogen pressures up to 205 atm. Typical results are illustrated and shown to compare favorably with data from previous investigations.

Synthesis gas production

Abstract: Raw synthesis gas produced by the gasification of coal, heavy oil or similar carbonaceous material is contacted with a reforming catalyst at a temperature in the range between about 1000° and about 1800° F. and at a pressure between about 100 and about 2000 psig prior to adjustment of the carbon monoxide-to-hydrogen ratio and treatment of the gas to increase its B.t.u. content. This catalytic reforming step eliminates C 2 + compounds in the gas which tend to form tarry downstream waste products requiring further treatment, obviates polymerization problems which may otherwise interfere with upgrading of the gas by means of the water gas shift and methanation reactions, and improves overall process thermal efficiency by making possible efficient low level heat recovery.

Synthesis gas from solid carbonaceous fuel

Abstract: This is an improved continuous partial oxidation process for producing synthesis gas or fuel gas from a solid carbonaceous fuel. Liquid CO2 and a ground solid carbonaceous fuel such as coal are mixed together to produce a pumpable slurry feed. The CO2 serves as a carrier for the carbonaceous fuel and as a temperature moderator, and is preferably obtained by purifying the product gas.

Coal injection system

Abstract: A caking coal or similar carbonaceous solid is introduced into a fluidized bed containing char particles at a temperature in excess of the coal resolidification point by entraining coal particles less than about 8 mesh on the Tyler Screen Scale in a gas stream preheated to a temperature in excess of about 300* F. but below the initial softening point of the coal, injecting the hot gas and entrained coal particles through a fluid-cooled nozzle maintained at a temperature below the initial softening point of the coal into the fluidized bed at a superficial gas velocity between about 15 and about 1,000 feet per second, monitoring the fines carried overhead by gas from the fluidized bed, and regulating the velocity at which the hot gas and entrained coal particles are injected into the bed through the nozzle in response to changes in the fines content of the gas to produce controlled attrition of agglomerated particles in the bed.

Ecology of Iron-Oxidizing Bacteria in Pyritic Materials Associated with Coal

Abstract: A technique was developed for measuring 14CO2 uptake by chemolithotrophic bacteria directly in pyritic materials associated with coal and coal refuse. There was good correlation between 14CO2 uptake, as determined by this technique, and the most probable number of iron-oxidizing bacteria. Maximal 14CO2 uptake occurred in coal refuse material 2 to 3 years old, and only slight incorporation was demonstrated in fresh material or material 40 years old. Samples taken from the surface of the coal refuse pile always demonstrated maximal 14CO2 uptake, and in most samples, only slight activity was demonstrated at depths below 8 to 10 cm. Optimal uptake of 14CO2 by natural samples occurred at 20 to 30 C and at a moisture content of between 23 and 35%. In addition to chemolithotrophic bacteria, heterotrophic fungi and yeasts were also routinely isolated in high numbers from acidic coal refuse. In contrast, acidophilic, heterotrophic bacteria were either absent or present in low numbers in such acidic samples.

Emissions of trace elements from coal fired power plants

Abstract: Elemental compositions of the coal, various ash fractions and suspended particles in the stack of the Chalk Point (coal fired) power plant in southern Prince George's County, Maryland have been measured by instrumental nuclear activation methods. Similar analyses were performed on ambient particulate samples collected at ground level by a network of stations near the plant and with a mobile sampling vehicle equipped with an SO/sub 2/ analyzer and condensation nuclei counter to detect the plume. This particular plant appears to cause less enrichment of moderately volatile elements on suspended particles in the stack (with respect to the input coal) than plants studied by other US groups. The enrichment factors (with respect to the earth's crust) of most elements on the emitted particles are rather similar to values observed for background ambient particles in the area. Thus, emissions from the plant raise the ambient concentrations of most elements on particles rather uniformly without greatly altering the pattern of relative concentrations. 7 references, 2 figures, 1 table.

Aqueous foam compositions to suppress coal dust

Abstract: Aqueous foamable compositions can be used to suppress coal dust, especially respirable coal dust, i.e., coal dust having particle size less than about 10 microns. These compositions are composed principally of water with a minor amount of an interpolymer of: A. a polymerizable vinyl ester and B. a partial ester compound interpolymerizable therewith selected from the group consisting of partial esters of ethylenically unsaturated aliphatic dicarboxylic acids and anhydrides containing from 4-8 carbon atoms and mixtures thereof; said dicarboxylic acid or anhydride having up to half of its acidic hydrogen atoms replaced by lower alkyl groups of 1-8 carbon atoms and mixtures thereof to bind the coal dust and give body to the foam, and a minor amount of a detergent wetting agent to promote foaming and the wetting of the coal by water. These interpolymers bind the coal dust and reduce or prevent reacrosolation after the foam has collapsed. These interpolymers also serve to give body to the foam, i.e., to promote the desired degree of stability of the foam which in most cases should be of limited duration. Especially good interpolymers are those which are soluble in water at room temperature (25°C.) in the amount required in the composition, e.g. vinyl acetate/maleic anhydride copolymer esters. Nonionic detergents, which are water soluble at room temperature in the amounts needed in the compositions, are suitable wetting agents for promoting foaming and wetting the coal dust. The foams should be of limited duration so as not to interfere with mining operations.

Nonisothermal Kinetics Studies of the Hydrodesulfurization of Coal

Abstract: Laboratory experiments with 10 bituminous coals were performed to study the nonisothermal kinetics of coal hydrodesulfurization The evolution of hydrogen sulfide during hydrodesulfurization was described by a sulfur release, in order of increasing temperatures, characterized by evolution of the following five sulfur types: Organic I, Organic II, pyrite, sulfide, and Organic III Notable exceptions were the evolution of H/sub 2/S by a process occurring in a temperature range intermediate to the pyrite and sulfide evolution peaks and a higher temperature H/sub 2/S evolution that was not reproducible and may have been an experimental artifact The most important back-reaction of H/sub 2/S with partially desulfurized coal was the inhibition of H/sub 2/S release by iron The reaction orders for sulfur removal in pyrite and Organic III were 05 and 2, respectively, rather than unity The former was rationalized by supposing the existence of an equilibrium between iron pyrite, iron, and adsorbed sulfur as well as a rate-determining step that involves reaction of hydrogen with adsorbed sulfur The latter case with a reaction order of 2 suggests that, in the rate-determining step of sulfur evolution from Organic III, two sulfur-containing species must be involved The Organic III form of sulfur may notmore » be an original component but rather the result of reaction of H/sub 2/S with partially desulfurized coal during hydrodesulfurization« less

Waste water processing

Abstract: Waste water formed in the gasification of coal and containing ammonia, H 2 S, and phenolic compounds is treated to remove H 2 S and a substantial proportion of its ammonia, while leaving sufficient ammonia in the water to maintain a pH of at least 8 (such as up to about 10.5, preferably about 8.5 to 9), the ammoniacal water is then flashed into a stream of superheated steam being fed to gasification zone. At the high temperatures in the gasification zone the organic impurities are decomposed.

The Gasification of Coal

Abstract: GAS MADE FROM COAL COULD SUBSTITUTE FOR NATURAL GAS IF THE OLD TECHNOLOGY OF COAL GASIFICATION COULD BE IMPROVED TO GIVE THE PRODUCT THE HEATING VALUE OF NATURAL GAS (1,030 BRITISH THERMAL UNITS PER CUBIC FOOT). THE UNENRICHED GAS FROM COAL COULD ALSO SERVE WELL IN MANY INDUSTRIAL APPLICATIONS. THE CONTINUING IMPROVEMENT IN COAL GASIFICATION TECHNOLOGY IS REVIEWED AND THE LURGI AND KOPPERS-TOTZEK PROCESSES (WHICH ARE COMMERCIALLY AVAILABLE) ARE DISCRIBED. THE FORMER IS A PRESSURIZED PROCESS IN WHICH WHICH SIZED COAL DESCENDING INTO THE GASIFIER IS FIRST DRIED AND THEN CARBONIZED BY REACTION WITH OXYGEN AND STEAM. IN THE GASIFIER'S BOTTOM LAYER, THE REMAINING CARBON IS BURNED TO PROVIDE HEAT FOR THE REACTIONS PROCEEDING ABOVE. THE KOPPERS-TOTZEK PROCESS EMPLOYS STEAM AND OXYGEN IN THE GASIFICATION STEP AND PROCEEDS AT ATMOSPHERIC PRESSURE. IT WILL WORK WITH ANY TYPE OF COAL. NEITHER OF THE COMMERCIAL PROCESSES YIELDS A GAS WITH THE HEATING VALUE OF NATURAL GAS, BOTH PROCESSES REQUIRE A METHANATION STEP IN WHICH THE GAS FROM THE COAL IS PASSED OVER A NICKEL CATALYST. SEVERAL NEW METHODS ARE BEING INVESTIGATED AND TWO HAVE REACHED THE DEMONSTRATION STAGE. THE BASIC STEPS IN TWO PROCESSES ARE CHARTED IN A DIAGRAM WHICH ILLUSTRATES HOW THE COAL IS PREPARED AS NECESSARY AND THEN DEVOLATALIZED. THIS ENTAILS HEATING IT IN THE ABSENCE OF AIR SO THAT IT DECOMPOSES CHEMICALLY, YIELDING VARIOUS GASES AND CHAR. ALSO ILLUSTRATED ARE THE HYGAS PROCESS, THE CARBON DIOXIDE ACCEPTOR PROCESS AND THE SYNTHANE PROCESS. THE BI-GAS PROCESS IS OUTLINED. UNDERGROUND COAL GASIFICATION IS DISCUSSED TOGETHER WITH SOME NEW TECHNOLOGICAL APPROACHES SUCH AS THE USE OF EXPLOSIVES AND DRILLING WITH LASERS.

Coal gasification ash removal system

Abstract: In a fluidized bed process for the gasification of coal or similar carbonaceous solids wherein char particles are withdrawn from a fluidized bed reaction vessel, transported to a second vessel, and later returned to the initial vessel, char particles of high ash content are separated from particles to be returned to the fluidized bed reaction vessel by injecting a dense phase stream of char particles including particles of both high and low ash content into a vertically moving gas stream having a velocity sufficient to transport relatively light particles of low ash content upwardly into the fluidized bed reaction vessel but insufficient to suspend relatively dense particles of high ash content, collecting the high ash content particles which are not entrained by the gas stream, and periodically withdrawing the collected particles from the system.

Demineralization of brown coal

Abstract: Demineralization of coal in which a slurry of the coal to be treated is ground in the presence of aqueous acid such as HCl H2 SO4 and H2 CO3 and then the slurry is subjected to froth flotation in the presence of a gas selected from Cl2, SO2, or CO2.

Solvent refined coal process with retention of coal minerals

Abstract: A solvation process for producing deashed solid and liquid hydrocarbonaceous fuel from coal. Raw coal is slurred with a solvent comprising hydroaromatic compounds in contact with hydrogen in a first zone to dissolve hydrocarbonaceous fuel from coal minerals by transfer of hydrogen from hydroaromatic solvent compounds to hydrocarbonaceous material in the coal. The slurry is then treated with hydrogen in a second zone to replenish the solvent with hydrogen. The process is improved by retention of coal minerals in the second zone.

Method for removal of sulfur from coal

Abstract: A process for reducing the amount of free and combined sulfur, such as pyritic, organic or elemental sulfur in coal; removing of these sulfur species may be made in an acid, basic or neutral solutions; at least 50 percent and up to 90 percent of sulfur, by weight, originally present in coal may be removed.