Showing papers on "Coal published in 1971"

Predicting the Combustion Behaviour of Coal Particles

Abstract: A mathematical model has been formulated to describe the combustion behaviour of single particles of pulverised bituminous coal and the predictions have been compared with experimental values obtained using a small tube furnace. The model was programmed for an analogue computer and incorporates data, much of it recently acquired, on the physical changes undergone by coal particles which are rapidly healed. It is concluded that for 60 μm diameter particles burning within the chemical control regime, increase in the radiating surface of the particles is of major importance in controlling their temperature and that this surface may be accounted for by fragmentation at an advanced stage of burnout. Between 1325° and 1450 °K the values for the surface reaction rate coefficient of the two chars investigated are between 0·04 and 0·14 times those of published data for carbon surfaces other than pyrolytic graphites. It is suggested that the differences may be attributed to the porous nature of the chars.

Fossil fuel combustion and the major sedimentary cycle.

Abstract: The combustion of the fossil fuels coal, oil, and lignite potentially can mobilize many elements into the atmosphere at rates, in general, less than but comparable to their rates of flow through natural waters during the weathering cycle. Since the principal sites of fossil fuel combustion are in the mid-latitudes of the Northern Hemisphere, changes in the composition of natural waters and air, as a consequence of this activity, will be most evident at these latitudes.

Fossil Fuels as a Source of Mercury Pollution

Abstract: The upper limit of the quantity of mercury released by weathering processes is approximately 230 metric tons per year. The quantity of mercury released by burning of coal is estimated to be of the order of 3000 tons per year, a quantity comparable to that emitted as waste from industrial processes.

Geology and fuel resources of the Fruitland Formation and Kirtland shale of the San Juan Basin, New Mexico and Colorado

Abstract: The San Juan Basin contains sedimentary rocks that range from Cambrian to Holocene in age and are as much as 15,000 feet thick. Upper Cretaceous rocks, which are more than 6,000 feet thick, are composed of intertonguing marine and nonmarine sedimentary rocks deposited during three basin-wide cycles of transgression and regression of an epicontinental sea. The final regression of the sea is represented by the marine Pictured Cliffs Sandstone. Fuel resources of the Fruitland Formation and the Kirtland Shale include uranium, oil, gas, and coal. The uranium occurs in channel sandstone in the Fruitland Formation. Oil and gas occur mostly in small scattered stratigraphic traps. The thickest coal beds occur in the lower part of the Fruitland Formation. The thickest coal occurs adjacent to and southwest of major stratigraphic rises of the Pictured Cliffs Sandstone. Analyses of Fruitland coal samples from rotary-drill cuttings show that the highest quality coal on an as-received basis underlies the northwestern part of the San Juan Basin. As-received Btu values in this area range from about 12,000 to more than 13,000. The coal from the washed drill cuttings is low in moisture content, between 2 to 6%. The ash content of the coal is unusuallymore » high and erratic, ranging from 10 to more than 30%. The lowest ash contents are in the west-central part of the basin; the highest ash contents are in the middle and eastern parts of the basin. The moisture and ash-free values and fixed-carbon ratios of the samples show a well-defined zonation across the basin paralleling the trends of deposition and the basin axis. Statistical analysis indicates that the Fruitland Formation in the San Juan Basin contains approximately 200 billion tons of coal in beds more than 2 feet thick at depths of as much as 4,500 feet. 27 figures, 8 tables.« less

Gasification of carbonaceous solids

Abstract: A CONTINUOUS PROCESS FOR THE GASIFICATION OF CARBONACEOUS SOLIDS, ESPECIALLY COAL, WHEREIN A SOLID, LOW-SULFUR FUEL AND METHANE RICH GAS COMPRISE PRINCIPAL PRODUCTS. THE PROCESS EMPLOYS TWO-STAGE GASIFICATION, EACH STAGE CHARACTERIZED BY SUPER-PRESSURE AND HIGH TEMPERATURES. IN STAGE 1, A LOW-SULFUR CHAR IS REACTED WITH OXYGEN AND SUPERHEATED STEAM AT AN ELEVATED TEMPERATURE AND PRESSURE TO PROVIDE A STAGE 1 PRODUCT GAS COMPRISING OXIDES OF CARBON AND HYDROGEN. IN STAGE 2 A CHARGE COMPRISING A CARBONACEOUS SOLID, SUCH AS COAL, IS HEATED AND REACTED UNDER METHANE FORMATION WITH STAGE 1 PRODUCT GAS AND SUPERHEATED STEAM TO PROVIDE A STAGE 2 PRODUCT GAS AND CHAR WHICH ARE THEREAFTER QUENCHED AND SEPARATED FOR PROVIDING GASEOUS AND LOW-SULFUR SOLID CHAR PRODUCTS. A PART OF THE SOLID CHAR PRODUCT IS WITHDRAWN FROM THE PROCESS FOR PROVIDING A LOW-SULFUR FUEL FOR A BOILER FUEL AND THE REMAINING PART IS RECYCLED TO STAGE 1 AND THERE REACTED WITH OXYGEN AND SUPERHEATED STEAM FOR PROVIDING ADDITIONAL STAGE 1 PRODUCT GASES. THE WITHDRAWN CHAR PRODUCT IS BURNED IN A BOILER FOR PROVIDING PROCESS STEAM AND THE GASEOUS STAGE 2 PRODUCT IS FURTHER TREATED FOR PROVIDING METHANE-RICH FUEL GAS AND SULFUROUS BY-PRODUCT.

Pulverized fuel delivery system for a blast furnace

Abstract: A pulverized fuel delivery system for a blast furnace in which pulverized coal is delivered in dense phase fluidized form into the blast furnace from gas pressurized tanks that are placed in communication, one at a time, in cyclical sequence with a pneumatic transport means. The tank gas pressure is regulated in accordance with the blast furnace wind rate to control the weight flow rate of pulverized coal into the furnace and the transport gas flow rate is regulated in accordance with the fuel weight flow rate to maintain a prescribed transport gas flow rate per pound of coal delivered to the furnace.

Re entrainment charging of preheated coal into coking chambers of a coke oven battery

Abstract: THE INVENTION HEREIN IS CONCERNED WITH A METHOD AND APPARATUS FOR CHARGING PREHEATED COAL INTO COKING CHAMBERS OF A COKE OVEN BATTERY, WHEREIN THE COAL IS PREHEATED, COARSELY COMMINUTED AND CONDUCTED VIA PIPELINE UNDER THE FORCE INDUCED BY A HIGHLY HEATED INERT GAS SUCH AS STREAM, WITH THE ASSISTANCE OF A RE-ENTRAINMENT BEND IN THE PIPELINE, ADAPTED TO EFFECT SUDDEN CHANGE IN DIRECTION OF THE FLOW OF COAL SO AS TO MOVE UPWARDLY AND INTO THE STREAM OF GAS, COAL WHICH SETTLED OUT OF THE STREAM AND ONTO THE BOTTOM, TO RE-ENTER THE SAME.

Hydrogenation of low rank coal

Abstract: LOW RANK COAL HAVING A HIGH OXYGEN CONTENT IS HYDROGENATED INTO HYDROCARBONACEOUS PRODUCTS WHILE REDURING THE HYDROGEN CONSUMPTION BY CONDUCTING THE HYDROGENATION OF SUCH COAL IN FIRST AND SECOND STAGE EBULLATED BED REACTION ZONES WITH THE SEPARATE WITHDRAWAL OF THE GASIFORM EFFUENT STREAM CONTAINING CARBON MONOXIDE AND CARBON DIOXIDE BETWEEN THE FIRST AND SECOND HYDROGENATION STAGES.

Application of Linear Programming to a Controversy on Air Pollution Control

Abstract: A linear programming model for air pollution abatement is presented. It is based on the simplifying assumption that air quality goals may be expressed as maximum allowable emission flows in an airshed. The solution of the model for the St. Louis Airshed is examined to evaluate certain charges that it is economically infeasible for purposes of air pollution control to impose restrictions on the sulfur content of coal. It is found that such a regulation is justified for certain types of stokers but not others, that furnaces with a heating efficiency of 75% or less should be converted to natural gas. Uncertainty over certain key parameters precludes judgment as to whether the use of low sulfur coal is optimal for pulverized coal furnaces.

Combustion of high-sulfur coal in a fluidized bed reactor

Abstract: Heating values are recovered from sulfur-containing coal in a reactor which includes a gasification zone, a combustion zone and a heat recovery zone. A fluidized bed of coal and limestone is maintained within the gasification zone, which is supported by a moving foraminous grate. Primary air, which is also the fluidizing medium, enters the gasification zone through the grate. The zone is operated adiabatically, under reducing conditions, to yield CaS and an effluent rich in CO. The CaS is discharged from the gasification zone by the moving grate and the gaseous effluent, containing entrained desulfurized coal fines, enters the combustion zone where secondary air is added. The exotherm of combustion is retrieved in the heat recovery zone, using conventional techniques. The flue gas from the reactor contains little sulfur dioxide to pollute the environment. The CaS may be processed in several ways to recover elemental sulfur.

Stabilization of coal

Abstract: A process for stabilizing dried lignitic and subbituminous coal against spontaneous combustion which comprises treating said dried coal at about 175* to about 225* C. with oxygen in an amount of from about 0.5 percent to about 8 percent by weight of said coal and rehydrating the oxygen treated coal with water in an amount of from about 1.5 percent to about 6 percent by weight of said oxygen treated coal.

Method for feeding dry coal to superatmospheric pressure

Abstract: A method for continuous feeding of dry coal particles from essentially atmospheric pressure to the superatmospheric pressure level of a coal gasifier or coal liquefaction reactor is achieved by a series of screw feeding devices each partially boosting the pressure level of the coal in stages to provide the dry coal at reactor pressure.

Removal of pyritic sulfur from coal

Abstract: Finely divided coal or coal derivatives, containing pyrite, are reacted with sulfurous acid (the oxidizing agent); if desired, HCl may also be used to improve the reaction efficiency to remove pyritic sulfur from coal as shown by the following equations: Primary: Oxidation - reduction 4 FeS2 (pyrite) +3SO2 + 12 HCl -> 4 FeCl3 + 11S + 6 H2O Secondary: Oxidation - reduction 4 FeCl3 + FeS2 (Pyrite) -> 6 FeCl2 + 4S Overall reaction 6 FeS2 + 3SO2 + 12 HCl -> 6 FeCl2 + 15S + 6 H2O The solution containing ferrous chloride and unreacted sulfurous acid is then filtered from the coal which is then washed and heat dried under low pressure. Most of the free sulfur is volatized from the coal due to the heat drying; additional free sulfur can be removed by additional washing and heat drying and/or solvent extraction techniques. If desired, the ferrous chloride can be oxidized to ferric oxide and hydrochloric acid. The hydrochloric acid may be recycled and the iron oxide used for production of steel or discarded.

Coal liquefaction using carbon radical scavengers

Abstract: COAL LIQUIFACTION YIELDS ARE INCREASED BY LIQUEFYING THE COAL IN A LIQUEFACTION ZONE AS A SLURRY IN A HYDROGENDONOR SOLVENT IN THE PRESENCE OF A CARBON RADICAL SCAVENGER SELECTED FROM QUINONES AND THE HALOGENS INDINE, BROMINE AND CHLORINE, AND THE HYDROGEN HALIDES THEREOF. PREFERABLY A COAL LIQUIDS STREAM WHICH BOILS WITHIN THE RANGE FROM ABOUT 500*F. TO ABOUT 1000*F. IS OXIDIZED TO GENERATE QUINONES, AND THE OXIDIZED STREAM IS RECYCLED TO THE LIQUEFACTION ZONE.

Slurries of solid carboniferous fuels

Abstract: Production of synthesis gas from a slurry of particulate solid carboniferous fuels, e.g., petroleum coke, coke from bituminous coal, coal, oil shale, tar sands, pitch, or mixtures of these materials in water or in a hydrocarbon liquid fuel. The amount of particulate solid carboniferous fuel in a pumpable slurry may be increased to 75 wt. percent and the particle size of the solid fuel may be increased to pass through a 12 mesh screen by the addition of 2 to 10 wt. percent of soot as produced, for example, by the partial oxidation of crude oil. The slurry at a relatively low velocity in the range of 5 to 50 feet per second is mixed with a stream of oxidizing gas at a relatively high velocity in the range of 200 feet per second to sonic velocity at the burner tip to form an atomized dispersion of water, hydrocarbon liquid fuel, oxidizing gas, and solid carboniferous fuel. Under synthesis gas generating conditions, the atomized dispersion is reacted to produce a gaseous mixture of hydrogen and carbon monoxide. By this process, pumpable slurry feeds of low cost solid carboniferous fuels may be gasified in a synthesis gas generator without being preheated.

Method of in situ coal gasification

Abstract: A method for distilling coal in situ through gasification to recover hydrocarbons and a calorific value gas by treating a rubblized bed of coal underground. A rubblized bed of coal is produced from the surface through wells or shafts sealed to convey fluids under high pressure to or from the coal bed. Superheated steam is injected into the chamber while volatized hydrocarbons and gaseous reaction products are simultaneously withdrawn. Subsequent to the removal of the volatile hydrocarbons, air is injected so as to initiate combustion of the remaining char and increase the chamber temperature to from about 1200*F. to about 2000*F. Air injection is then suspended with water or low temperature steam being introduced into the hot char in order to form superheated steam which is withdrawn and injected into a new rubblized chamber of coal to repeat the process.

Multi-hydrotorting of coal

Abstract: A NONCATALYTIC MULTI-HYDROTORTING PROCESS FOR MAXIMIZING THE CONVERSION OF COAL INTO COAL OIL. A PUMPABLE COAL-WATER SLURRY IN ADMIXTURE WITH A STREAM OF SYNTHESIS GAS IS PASSED THROUGH A TUBULAR RETORT WHERE IT IS HEATED TO A TEMPERATURE IN THE RANGE OF ABOUT 600 TO 950* F. IN THE ABSENCE OF AIR. THE SOLID COAL PARTICLES ARE FRAMENTIZED AND CARBONIZED IN THE TUBULAR RETORT, THE VOLATILE CONSTITUENTS IN SAID SLURRY ARE VOLATILIZED AND SIMULTANEOUSLY HYDROGENATION OF THE PROCESS STREAM TAKES PLACE. THE EFFLUENT FROM THE TUBULAR RETORT IS THEN INTRODUCED INTO A FLUIDIZED BED RETORT ALONG WITH A SECOND STREAM OF SYNTHESIS GAS. THERMAL DECOMPOSITION OF THE CARBONACEOUS MATERIALS TAKES PLACE IN THE ABSENCE OF AIR AND THE PROCESS STREAM IS HYDROGENATED FOR A SECOND TIME. THE PROCESS STREAM LEAVING THE FLUIDIZED BED RETORT IS COOLED TO CONDENSE OUT AND SEPARATE WATER AND RAW COAL-OIL IN A GAS-LIQUID SEPARATION ZONE. A PORTION OF THE OFF-GAS FROM THE GAS-LIQUID SEPARATOR MAY BE SCRUBBED AND PURIFIED TO PRODUCE NONPOLLUTING FUEL GAS HAVING A HIGH HEATING VALUE. SPENT CARBONACEOUS PARTICLES LEAVING THE FLUIDIZED BED RETORT AND OPTIONALLY A PORTION OF THE OFF-GAS FROM THE GAS-LIQUID SEPARATOR ARE INTRODUCED INTO A FREE-FLOW NONCATALYTIC GAS GENERATOR FOR CONVERSION INTO PREFERABLY HYDROGEN-RICH SYNTHESIS GAS BY PARTIAL OXIDATION FOR USE IN THE AFORESAID TWO HYDROTORTING STAGES.

Removal of pyritic sulfur from coal using solutions containing ferric ions

Abstract: Finely divided coal or solid coal derivatives containing pyrite are reacted with a ferric ion solution; FeCl3 is particularly suitable. The ferric ion is reduced to ferrous ion and free sulfur is formed. The solution is then filtered from the coal which is then washed and heat dried under low pressure. Most of the free sulfur is volatized from the coal due to the heat drying; additional free sulfur can be removed by additional washing and heat drying and/or solvent extraction techniques. At least 60 percent of the pyrite sulfur and pyrite iron is removed using the process of this invention. If desired, the ferrous chloride can be regenerated; this permits iron oxide to be recovered as a byproduct.