Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L5/00—Solid fuels
  • C10L5/02—Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin
  • C10L5/26—After-treatment of the shaped fuels, e.g. briquettes
  • C10L5/32—Coating
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L9/00—Treating solid fuels to improve their combustion
  • C10L9/10—Treating solid fuels to improve their combustion by using additives

Definitions

• 3,140,241 and 3,140,242, issued July 7, 1964 is treated with an aqueous dispersion of a film former to deposit on and adjacent the surface thereof from about 0.05 to about 3 weight percent of a solid which adheres to the surface and deposits in the surface pores, and acts both to reduce abrasion and to cause material abraded from the surface to be larger in size than the ultrafine (20-micron and smaller) particles which are produced in the absence of the coating, thereby controlling the airborne-dust problem which otherwise makes handling of the reactive form coke extremely diflicult.
• coke has been made from coking coals in by-product or beehive ovens; the coke is obtained as a mass which is discharged from the furnace in the form of lumps of irregular shape.
• the coke In handling-particularly in shippingthe edges and corners of these lumps break oif as fines, which cause difiiculty in maintaining bed porosity in the blast furnace, and difficulties in the dust-collecting systems associated therewith.
• the fines produced are relatively coarse and are airborne with difiiculty in normal handling. This tendency to produce fines is generally tested according to the American Society for Testing and Materials test method ASTM D-294-64, called the Tumbler Test.
• Results are reported as the hardness factori.e.the weight of the coke sample that is retained onthe A" standard sieve after tumbling.
• any coke that degraded in handling to a size that will pass through the 4" standard sieve is removed by in-transit screening as the coke moves from the supply dump to the skip car for charging to the blast furnace, so that the hardness factor measures the coke available for actual charging to the furnace.
• This invention aims to provide a means of overcoming the problem of airborne dust associated with long rail shipments and handling of products produced by the methods described in US. Pats. 3,140,241 and 3,140,242, without interfering with its utility in blast furnaces and for other uses.
• treating reactive form coke in accordance with this invention eliminates the need for in-transit screening, greatly facilitates the coke handling operations and tends to lower production costs.
• this invention is designed to control a problem which seems to be unique with the carbonaceous briquettes made in accordance with US. Pats. 3,140,241 and 3,140,242.
• a reactive calcinate is made by catalyzing coal particles by heating in the presence of added oxygen (US. Pat. 3,140,241) or oxygen in the coal (US. Pat. 3,140,242) to a temperature above 250 F.
• Reactive form coke withstands the ASTM Tumbler Test better than conventional coke, but after long rail shipments and bulk hand ing produces the series dusting problem hereinabove referred to.
• the reactive form coke is preferably treated while it is still hot, so that the water in the coating largely driven oil by the heat.
• cold treatment is also efiective, except that the water added 18 not completely removed by air evaporation.
• any film-forming solid we have used is necessary to get the desired results; more than 3.0% will ordinarily cause difiiculty with one or more desirable properties of the reactive form coke, for exam- 'ple they may tend to stick together when piled n large heaps.
• the additives function as cements for the ultrafine particles, thus again reducing the amount of nltrafines.
• the films are more resistant to abrasion Itfilllan the reactive form coke itself, resulting in less total It is essential that the film former be added in water.
• organic solvents are used, there is a tendency tor the film formers to be carried into the reactive form coke well below the surface, so that the desired concentration on and adjacent to the surface is not obtained; more film former is needed to control dusting, resulting in too great a change in the reactive form coke properties.
• solvent is trapped inside the reactive form coke, and must be driven out in a heating step.
• aqueous dispersions do form the desirably thin films, and penetrate the surface just enough to anchor the films and thicken the surface walls. But the aqueous dispersions just penetrate the surface pores; the high surface tension of the water apparently prevents undesirable deeper penetration.
• the test consists of charging approximately grams (to the nearest whole briquette) of carbonized briquettes to a 5" diameter, 10 mesh sieve with a 2" high wall.
• the sieve is attached to a vibrator such as the Vita-Surge SPN 74207 which moves the screen at 60 cycle frequency between Vs and A" in a horizontal direction.
• the test is run for 30 minutes, when the fines generated are screened through a 325 mesh sieve (44 microns) screen and the material passing through the screen isweighed.
• This test can be used for all sizes of briquettes by changing the screen, and the time can be varied as desired to simulate any changes in the actual haulage and handling conditions. The specific conditions were picked to get the same results as those obtained in actual large scale tests.
• EXAMPLE 2PETROLEUM RESIN EMULSION The same base sample as used in Example 1 was used except that lOO-g'ram samples were treated with a dilute (5%) aqueous emulsion of a hard petroleum resin, to
• Percent additive Percent fines, 325 mesh None 0.66 0.05 0.07 0.1 0.06 0 5 0.002
• Percent additive Percent fines, 325 mesh EXAMPLE 4-COAL TAR PITCH EMULSION A 5% coal tar pitch emulsion was used on a sample of reactive form coke which produced 0.32% fines by the Vibration Test. A 0.5% coating reduced the fines to 0.02% 325 mesh.
• the method of controlling the dusting tendencies of reactive form coke briquettes which will rub against each other to form very fine dust of 325 mesh size which is easily air-borne which comprises coating and reinforcing the surface layers thereof by applying thereto an amount of an aqueous dispersion of a solid film former to produce a film, on the surface and in the pores immediately adjacent thereto, which contains from 0.05 to 3%, based on the original weight, of the solid film-former, the solid film-former lacking abrasion resistance of itself but having abrasion resistance when applied to the reactive form coke briquettes, whereby the dust resulting from abrasion is increased in size and the amount of 325 dust is substantially reduced.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• Engineering & Computer Science (AREA)
• Combustion & Propulsion (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=22333958

Family Applications (1)

Country Status (7)

Cited By (7)

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Family Cites Families (2)

• 1971
  • 1971-01-28 US US00110608A patent/US3711318A/en not_active Expired - Lifetime
  • 1971-12-15 AU AU36919/71A patent/AU455538B2/en not_active Expired
  • 1971-12-24 CA CA131,131A patent/CA945023A/en not_active Expired
• 1972
  • 1972-01-26 FR FR7202617A patent/FR2123451B1/fr not_active Expired
  • 1972-01-27 GB GB382272A patent/GB1366395A/en not_active Expired
  • 1972-01-27 BE BE778592A patent/BE778592A/xx not_active IP Right Cessation
  • 1972-01-28 DE DE19722204103 patent/DE2204103A1/de not_active Ceased

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