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WO1986002663A1 - Procede de traitement du charbon et produit obtenu par ce procede - Google Patents

Procede de traitement du charbon et produit obtenu par ce procede Download PDF

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Publication number
WO1986002663A1
WO1986002663A1 PCT/US1985/000273 US8500273W WO8602663A1 WO 1986002663 A1 WO1986002663 A1 WO 1986002663A1 US 8500273 W US8500273 W US 8500273W WO 8602663 A1 WO8602663 A1 WO 8602663A1
Authority
WO
WIPO (PCT)
Prior art keywords
coal
ash
ozone
mixture
sulfur
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US1985/000273
Other languages
English (en)
Inventor
George E. Brown, Jr.
Bruce N. Hoppert
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Brown Coal Corp
Original Assignee
Brown Coal Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US06/666,135 external-priority patent/US4543104A/en
Application filed by Brown Coal Corp filed Critical Brown Coal Corp
Publication of WO1986002663A1 publication Critical patent/WO1986002663A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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
    • C10L9/00—Treating solid fuels to improve their combustion
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B1/00—Conditioning for facilitating separation by altering physical properties of the matter to be treated
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B9/00—General arrangement of separating plant, e.g. flow sheets
    • B03B9/005—General arrangement of separating plant, e.g. flow sheets specially adapted for coal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
    • B03D1/00—Flotation
    • B03D1/02—Froth-flotation processes

Definitions

  • Coal has been utilized as a fuel for many centuries, usually as it has been taken from the mine. While it has a high heat or B.T.U. value, it has the disadvantage of containing a large amount of contaminating ash.
  • This ash consists of non-combustible materials such as clays, sand shale and other earth derived minerals. It also contains sulfur containing materials, principally pyrite or FeS 2 but also some organic sulfur containing compounds in the coal.
  • Coal that has been crushed to a size range of 1/2 inch or less is mixed with water so as to form a mixture of about 10 to 40 percent by weight coal and preferably 20 to 35 percent by weight coal.
  • Ozone is pumped into the bottom of the coal water mixture during agitation at a rate of about 1/10 to 5 pounds per ton of coal and perferably about 1/2 to 1 pound per ton of coal.
  • a series of separation steps are employed to separate the coal from the ash and sulfur.
  • the objectives of this invention are to provide a product to the heat using industries which has the following characteristics:
  • a clean fuel source that is economical to produce, drastically cuts shipping costs at the boiler, reduces the load on. the scrubber and the sludge disposal costs, and reduces the moisture content thereby eliminating the evaporation loss of heat during burning;
  • a clean fuel source that may be prepared from an almost unlimited supply of raw material including surface or deep-mined coal, waste coal from slurry ponds or gob piles, or lignite deposits;
  • a clean fuel source that helps to broaden the use of coal by increasing the free swelling index or "coke button” value of the processed coal thus enabling the metals industry to use lower price coal for coking purposes;
  • Ash constituents are found in layers of various thickness throughout the coal, loosely bound to the coal molecules by weak chemical bonds. It was found that these bonds could be broken and the coal separated and further modified by the use of high energy compounds. It was also found that this transformation was not pH dependent, but only energy dependent, and could be accomplished by either oxidation, reduction or both, and could be done in aqueous medium thereby eliminating expensive dry processing techniques.
  • the preferred embodiment of the invention utilizes ozone, a triatomic form of oxygen, of high energy, to accomplish the initial bond breaking between the coal and the ash constituents.
  • ozone a triatomic form of oxygen, of high energy
  • the coal produced by the present process has a very high coke button value, making certain types of coal very suitable for use in producing metallurgical coke.
  • ozone treatment as described would lower the coke button value since it is known that the button is reduced due to oxida- tion of the coal.
  • the present process provides a final coal product that is very low in ash and sulfur. This is in part due to the unique sequence of separation steps employed. Wore particularly, and in contrast to prior art processes, a water separation step is employed immediately after the coal-water mixture is treated to separate the ash and sulfur components. Conventional processes do not employ a water separation step at such an early point in the process. It is believed that such an early separation step contributes significantly to the improved results, especially ash and sulfur reduction, obtained by the present process.
  • the coal preferably in a size range of 1/2" down is pulped with water and placed in an agitated vessel 10 to form a coal water mixture.
  • the apparatus of Fig. 5 is preferred.
  • the mixture to the vessel 10 comprises 10 to 50 percent by weight coal and preferably 16 to 25 percent by weight coal.
  • ozone prepared by convention means 9, i.e., by high voltage corona contact with air, is pumped into the bottom of the agitated vessel 10.
  • the amount of ozone required will vary depending on the amount of ash in the coal and on other properties of the coal. While there will be some variance it has been found that about 1/3 to 5 pounds of ozone per ton of coal will suffice with the preferred range usually being 1/2 to 1 pound.
  • the ozone being unstable in the presence of water, rapidly breaks down releasing atomic oxygen of high energy content It is believed that the ozone breaks the bond between the coal and the ash constituents, and further attacks the organic molecules in the coal particle, opening ring structures (benzene types) and converting the coal into a highly hydrophobic Pave.
  • the coal-ash bond breaking proceeds along the boundary layer, opening up channels in the cellular nature of the coal and further reducing particle size as the ash-boundary layer weakens and breaks.
  • the clean hydrophobic coal particle is then free to further react on the surface to open ring structures and break aliphatic chains, particularly at the sulfur bonds which are much weaker than the carbon bonds in the coal structure.
  • the coal-water mixture is pumped to a suitable screen 12 of conventional design where the coal is washed and drained on a 150 mesh wire cloth.
  • a different mesh could be employed depending on the economics of the recovery process.
  • the largest part of the ash constituents are removed on the screen along with the less than 150 mesh coal.
  • the retained product is then fed to separating equipment 14 of either conventional centrifugal cyclone type or gravity Deister table type (Deister is a trademark for separating equipment sold by Deister Concentrator Company Inc.
  • the underflow from the first separating screen is pumped to a froth flotation cell 20 of conventional design where diesel fuel is added. Approximately 1/4 to 2 percent by weight and preferably 1/2 to 1 percent diesel fuel or similar material such as pure oil is employed.
  • diesel fuel Approximately 1/4 to 2 percent by weight and preferably 1/2 to 1 percent diesel fuel or similar material such as pure oil is employed.
  • the extremely hydrophobic nature of the coal displays itself in the rapid agglomeration of the coal by the diesel oil on the organophillic coal particles. Collection of the froth and allowance of the froth to collapse and dewater yields a low ash and moisture coal product, far in excess of what can be standardly expected from these cells.
  • the remaining ash constituents along with the nitrogen compounds are settled from the water stream and used to restore the environment of the strip mined areas, as the growth support qualities of the ash are exceptional. Nitrogen values increase in the ash material range from 1/2% to 5% depending on what is desired in the area to be restored.
  • coal can be used as an energy source. If desired, and it is not required, a further treatment of the coal after it passes through centrifuge 18 can be provided.
  • the coal can be put in a slope bottomed tank not shown so that it flows across a metal contact plate in the bottom, with a surface contact plate in the water containing a small percentage of sodium hydroxide.
  • An electric potential of about 6 to 24 volts at from 6 to 100 amps is then applied and the coal itself in contact with the bottom plate, becomes the electrode in an electrolytic cell, in this case the cathode. It is believed that sodium ions attracted to the coal, are neutralized to sodium atoms, and immediately react with the water to form nascent hydrogen.
  • nascent sodium (high energy) and nascent hydrogen (also high energy) completes the cleaning action by solublizing silica as sodium silicate, and furthe reducing pyritic material and organic sulfur to hydrogen sulfide.
  • Coal product from the reduction step is thereafter screened and centrifuged to a very low dryness.
  • the coal produced has different surface characteristics than coal produced by other methods.
  • the particles are exceptionally clean and have very high light reflective values. Under microscopic examination, the coal particles show very little or no ash or sulfur entrapped within the particles. What little that does exist does so in separate and discrete particles.
  • coals from various sources treated by one or both steps and the ash and sulfur reductions and moisture levels attained and enhanced B.T.U. values may be attained in accordance with the following examples:
  • Example 1 Eastern Kentucky Coal - 42% ash, 1.4% sulfur, 6700 B.T.U. no F.S.I. treat at 25% solids suing 30# of coal and 30 grams of O 3 for 30 minutes while being agitated. After screening and passage across a Deister table, in accordance with the above procedure, the product is centrifuged to an 8% moisture level with the following approximate values. 3.1% ash, 0.6% sulfur, 13,850 B.T.U. and an 81 ⁇ 2 F.S.I.
  • Example 2 Alabama Coal - 36% ash - 1.7% sulfur, 8000 B.T.U. treat at 25% solids using 30# of coal and 30 grams of O 3 for 30 minutes while being agitated. After screening and passage across a Deister table in accordance with the above procedure, the following approximate values are obtained. Ash 2.91%, sulfur 0.7%, 13,940 B.T.U. 9% moisture.
  • Example 3 Alabama lignite - 28% ash, 24% moisture, 4.2% sulfur, 5200 B.T.U. treat at 25% solids using 30# of lignite and 45 grams of 0, for 30 minutes while being agitated. After screening and passage across a Deister table the following approximate values are obtained. Ash 3.2%, sulfur 1.7%, B.T.U. 13,740, moisture 6.8%.
  • Example 4 Illinois Coal - 52% ash, 2.1% sulfur, 4,850 B.T.U. No F.S.I. treat at 25% solids using 30# of coal and 60 grams of O 3 while being agitated. After screening and passage across a Deister table the following approximate values are obtained. 4.08% ash, 0.9% sulfur, 13,600 B.T.U., 61 ⁇ 2 F.S.I., 8.2% moisture.
  • Example 5 Coal from run #4 from Illinois is mixed with water to a 25% moisture level and placed in a polyethylene bag and put in a refrigerator freezer compartment for 24 hours at 0°F. At the end of 24 hours the coal is free flowing and easily handled without the formation of frozen lumps. It is also true of Eastern Kentucky Coal. The ice crystals are discrete and are not attached to the coal par- tides.
  • Example 6 Ohio Coal - 24% ash, 6.5% sulfur, 8,350 B.T.U. treat at 25% solids using 30# of coal and 60 grams of O 3 while being agitated. After screening and passage across a Deister table the following approximate values are obtained. 3.8% ash, 1.6% sulfur, 13,450 B.T.U.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Solid Fuels And Fuel-Associated Substances (AREA)

Abstract

Un procédé de traitement de charbon consiste à traiter du charbon brut avec de l'ozone (O3) en suspension aqueuse (conteneur agité 10) pour modifier la surface des particules de charbon et libérer les constituants de cendres (séparateur 14) permettant ainsi une séparation plus complete du charbon par des moyens conventionnels. Le procédé permet également d'obtenir un mélange qui est facilement déshydraté (centrifugeuse 18) et donne comme résultat un combustible propre.
PCT/US1985/000273 1984-10-30 1985-02-19 Procede de traitement du charbon et produit obtenu par ce procede Ceased WO1986002663A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US06/666,135 US4543104A (en) 1984-06-12 1984-10-30 Coal treatment method and product produced therefrom
US666,135 1984-10-30

Publications (1)

Publication Number Publication Date
WO1986002663A1 true WO1986002663A1 (fr) 1986-05-09

Family

ID=24672968

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1985/000273 Ceased WO1986002663A1 (fr) 1984-10-30 1985-02-19 Procede de traitement du charbon et produit obtenu par ce procede

Country Status (3)

Country Link
EP (1) EP0197938A1 (fr)
AU (1) AU3997385A (fr)
WO (1) WO1986002663A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE197810C (fr) *
US3824084A (en) * 1972-10-10 1974-07-16 Chemical Construction Corp Production of low sulfur coal
US3993456A (en) * 1975-02-24 1976-11-23 Texaco Inc. Process for desulfurizing pipelined coal
US4260394A (en) * 1979-08-08 1981-04-07 Advanced Energy Dynamics, Inc. Process for reducing the sulfur content of coal
US4412839A (en) * 1979-11-13 1983-11-01 Ergon, Inc. Coal treatment process
US4436618A (en) * 1979-03-05 1984-03-13 The Broken Hill Proprietary Company Limited Recovery of coal from coal handling operations

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE197810C (fr) *
US3824084A (en) * 1972-10-10 1974-07-16 Chemical Construction Corp Production of low sulfur coal
US3993456A (en) * 1975-02-24 1976-11-23 Texaco Inc. Process for desulfurizing pipelined coal
US4436618A (en) * 1979-03-05 1984-03-13 The Broken Hill Proprietary Company Limited Recovery of coal from coal handling operations
US4260394A (en) * 1979-08-08 1981-04-07 Advanced Energy Dynamics, Inc. Process for reducing the sulfur content of coal
US4412839A (en) * 1979-11-13 1983-11-01 Ergon, Inc. Coal treatment process

Also Published As

Publication number Publication date
AU3997385A (en) 1986-05-15
EP0197938A1 (fr) 1986-10-22

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