US3579442A - Coal converting process - Google Patents

Coal converting process Download PDF

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Publication number
US3579442A
US3579442A US53508A US3579442DA US3579442A US 3579442 A US3579442 A US 3579442A US 53508 A US53508 A US 53508A US 3579442D A US3579442D A US 3579442DA US 3579442 A US3579442 A US 3579442A
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coal
fraction
fractions
moisture content
finest
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US53508A
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Jack N Gerwig
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Bird Machine Co Inc
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Bird Machine Co Inc
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    • 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
    • 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

Definitions

  • a process for converting coal containing refuse to a useable coal product of a predetermined maximum moisture content comprising the steps of separating wet, refuse-containing coal into fractions according to particle sze, including a finest fraction and one or more larger fractions, removing refuse at least from the larger fractions, dewaterng the larger fraction to a moisture content below the predetermined maximum, and mechanically dewatering the finest fraction in a continuous centrifuge constructed to provide a finest coal output having a moisture content above the predetermined maximum which, when the fractions are all recombined, will provide a combined moisture content within the predetermined maximum t0 form said product.
  • This invention relates to cleaning coal.
  • thermal dryers creates more problems. Not only can the fine coal particles cause fires in, or be largely lost in the thermal dryers; in addition, hot coal from thermal dryers, unless subjected to a timeconsuming cooling step, can cause hot spots and therefore fires in the storage bins in which the cleaned coal fractions are collected.
  • the inventon features a process for converting coal contaning refuse to a useable coal product of a predetermined maximum moisture content, comprising the steps of separating Wet, refuse-containing coal into fractions according to particle sze, includng a finest fraction and one or more larger fractions, removing refuse at least from the larger fractions, de watering the larger fraction to a moisture content below the predetermined maximum, and mechanically dewaterng the finest fraction in a continuous centrifuge constructed to provide a finest coat output having a moisture content above the predetermined maximum which, when the fractons are all recombined, will provide a combined moisture content within the predetermined maximum.
  • a finest fraction consisting substantally of 10 mesh and finer particles is dewatered in a screen bowl centrifuge; and, the maximum moisture content is 6%, the finest fraction is dewatered to about 13% or less, the largest fraction to about 3% or less and another fraction, intermediate of the largest and smallest, to about 8% or less, both of the larger fractions being dewatered in oscillating centrifuges.
  • the finest fraction has refuse removed therefrom in flotation apparatus, prior to dewatering, and in another embodiment the finest fraction is the underflow from a cyclone separator (preferably, being particles in the range of 200 mesh and larger).
  • the intermediate fraction is thermally dewatered in a thermal dryer.
  • the recombining of this thermally dewatered fraction with the mechanically dewatered finest fraction causes the thermally dewatered coal to be cooled with simultaneous vaporization of moisture from the finest fraction.
  • FIG. 1 is a schematic flow sheet of a coal treating process embodying this invention.
  • FIG. 2 is a portion of a flow sheet for another coal treating process embodyng this invention, this portion for replacing the similarly dash line enclosed portion of the process of FIG. 1, with the remainder of this process being otherwise identical to that of FIG. 1.
  • raw coal having particles of 1%" and smaller is mechanically separated by sizing screen 12 at /8" into a large fraction (1%t" x /a") and a smaller fraction (about 30% solids, maximum particle size about
  • the larger fraction passes to a mechanical dryer 14 (e.g., an oscillating centrifuge such as described in U.S. Pat. No. 3,133,879) which provides as underflow a clean, dewatered fraction (about 2-3% moisture) for storage bin 16 (e.g. a railroad car).
  • the smaller fracton, together with efliuent from dryer 14, are passed to a mechanical cleaner 18 (e.g. washing cyclones, Deister tables, F.C.
  • the cleaned coal fraction from separator 18 is fed to another sizing screen 20, which makes a separation at 28 mesh.
  • the larger particles, a medium fraction, x 28 mesh pass to a mechanical dryer 24 (e.g., also an oscillatng centrifuge like dryer 14), where it is dewatered to an underflow of about 78% moisture, which is fed to st0rage bin 16.
  • the eflluent from dryer 24 is admixed with efiuent from dryer 14 upstream of cleaner 18.
  • the finest fraction (28 mesh x 0) from szing screen 20 passes to a conventional froth flotation apparatus 30, wherein the denser and smoother refuse particles (e.g., ash) are separated from the lighter, coarser coal particles.
  • the clean coal slurry from the flotation cells typically having a moisture content of 6575% passes to a continuous screen bowl centrifuge 34 (e.g. such as described in U.S Pat. No. 3,348,767) wherein the moisture content is reduced sufliciently (e.g., down to 12- 13%) to allow the resultant dewatered fraction to be passed directly to storage bin 16.
  • Centrifuge 34 has two efiluents, of which that from the downstream screen portion is returned to flotation apparatus 30.
  • Refuse from cleaner 18 passes to refuse dewatering screen 40, and thence to refuse container 42.
  • the effluent from screen 40, together with refuse from froth flotation apparatus 30 and the effluent from the upstream imperforate portion of screen bowl centrifuge 34 all pass to a refuse thickener 48 (e.g., gravity-type clarifier), of which the overflow may be recirculated (e.g., for initial wetting of coal, etc.), and the underflow is sent to a 3 mechanical dewatering apparatus 50 (e.g. a solid bowl centrifuge such as descrbed in U.S. Pat. No. 3228,593).
  • the solids emerging from dewatering apparatus 50 are fed to refuse container 42, whereas efliuent is recirculated to thickener 48.
  • one or both the cleaned x 28 mesh and /8" x 1%" fractions exiting mechanical dryers 14 and 24 may be passed to a thermal dryer (indicated in phantom at 52) prior to being loaded into storage bin 16.
  • the fine moist coal particles frorn centrifuge 34 cool the thermally dried coal sufliciently to prevent hot spots or fires in the storage bin, while at the Same time being further dried by the hot coal mass from the thermal dryer.
  • the fine particles are not passed to the thermal dryer, they are completely recovered and, additionally, operation of the dryer is unimpeded. The moistness of the fine particles furthermore eliminates dust probêts in the storage bin.
  • FIG. 2 shows a hydrocyclone cleaner 60 in place of the flotation apparatus 30 of FIG. 1, connected to receive 28 mesh x partcles from sizing sereen 20.
  • the cleaner is constructed to make a separation at about 200 mesh, and pass, as underflow, 28 x 200 mesh coal, together with a tolerably low level of ash particles, to sereen bowl centrifuge 34.
  • the waste overflow or efliuent from cyclone cleaner 60 is passed to thickener 48.
  • the dewatering action of sereen bowl 34 is suflicient to reduce the underflow from cyclone cleaner 60 to a level suitable for admixture with the 1% x and x 28 mesh fractions to produce an acceptably 1ow moisture content in the product of bin 16.
  • the separation into the finer and coarser fractions is carried out at different mesh sizes in different coal processing operations, 28 mesh being shown as illustrative only. For example, up to about mesh particles can be handled in fiotation cells.
  • the moisture content of the finished coal product in the storage bin is not greater than about 6%, and hence is suitable for most purposes.
  • This 10W is achieved without thermal drying by use of a continuous centrifuge to reduce the moisture content of the finest fraction to a sufiicently low level that, when that fraction is recombined with the larger fractions, the total mixture has a moisture content of about 6% or less.
  • the total moisture content of the coal mixture passing to the storage bin may be even further reduced.

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  • 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)
US53508A 1970-07-09 1970-07-09 Coal converting process Expired - Lifetime US3579442A (en)

Applications Claiming Priority (1)

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US5350870A 1970-07-09 1970-07-09

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US (1) US3579442A (enrdf_load_stackoverflow)
BE (1) BE768877A (enrdf_load_stackoverflow)
CA (1) CA920809A (enrdf_load_stackoverflow)
DE (1) DE2134436A1 (enrdf_load_stackoverflow)
FR (1) FR2098008A5 (enrdf_load_stackoverflow)
GB (1) GB1288016A (enrdf_load_stackoverflow)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4021206A (en) * 1975-02-10 1977-05-03 Shell Oil Company Separating coal particles from water
US4072539A (en) * 1976-11-22 1978-02-07 William Benzon Method of cleaning raw ore
US4126426A (en) * 1977-06-14 1978-11-21 Shell Oil Company Agglomerating coal slurry particles
US4175035A (en) * 1978-02-27 1979-11-20 Bethlehem Steel Corporation Method for increasing fine coal filtration efficiency
US4216082A (en) * 1977-01-07 1980-08-05 Shell Oil Company Method for processing a slurry of coal particles in water
US4244813A (en) * 1979-08-08 1981-01-13 Bethlehem Steel Corporation Method of increasing fine coal filtration efficiency
US4257879A (en) * 1976-10-21 1981-03-24 Bergwerksverband Gmbh Process for dewatering coal slurries
US4325819A (en) * 1980-09-25 1982-04-20 Altizer Dwight W Coal washing plant
US4385995A (en) * 1979-03-26 1983-05-31 Dondelewski Michael A Method of recovering and using fine coal
US4938864A (en) * 1988-08-23 1990-07-03 Mare Creek Industries, Inc. Method for processing fine coal
US5522510A (en) * 1993-06-14 1996-06-04 Virginia Tech Intellectual Properties, Inc. Apparatus for improved ash and sulfur rejection
US6156083A (en) * 1998-02-05 2000-12-05 Tuboscope Coal reclamation systems
EP1892281A1 (de) * 2006-08-22 2008-02-27 S.C. Ceramica International S.r.l. Verfahren zur Herstellung eines Ersatzbrennstoffes für eine Verwendung in Kohlekraftwerken und/oder Müllverbrennungsanlagen und/oder Anlagen der Zementindustrie oder sonstigen Verbrennungsanlagen, in denen feste Brennstoffe verwendet werden
CN105772212A (zh) * 2016-04-25 2016-07-20 中国矿业大学 一种中等粘结性煤生产特种白水泥用煤方法
CN108855586A (zh) * 2017-05-12 2018-11-23 杨林 一种浮游选煤的联合机组
CN110961241A (zh) * 2019-11-05 2020-04-07 乌拉特中旗毅腾矿业有限责任公司 一种高效环保浮选入料工艺及其筛分装置
CN116294533A (zh) * 2023-03-15 2023-06-23 中国矿业大学 一种多能量场梯级处理智能化决策的气化细渣脱水方法
US20240253060A1 (en) * 2023-01-30 2024-08-01 Somerset International Finance Designated Activity Company Methods and systems for classification and recovery

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4021206A (en) * 1975-02-10 1977-05-03 Shell Oil Company Separating coal particles from water
US4257879A (en) * 1976-10-21 1981-03-24 Bergwerksverband Gmbh Process for dewatering coal slurries
US4072539A (en) * 1976-11-22 1978-02-07 William Benzon Method of cleaning raw ore
US4216082A (en) * 1977-01-07 1980-08-05 Shell Oil Company Method for processing a slurry of coal particles in water
US4126426A (en) * 1977-06-14 1978-11-21 Shell Oil Company Agglomerating coal slurry particles
US4175035A (en) * 1978-02-27 1979-11-20 Bethlehem Steel Corporation Method for increasing fine coal filtration efficiency
US4385995A (en) * 1979-03-26 1983-05-31 Dondelewski Michael A Method of recovering and using fine coal
US4244813A (en) * 1979-08-08 1981-01-13 Bethlehem Steel Corporation Method of increasing fine coal filtration efficiency
US4325819A (en) * 1980-09-25 1982-04-20 Altizer Dwight W Coal washing plant
US4938864A (en) * 1988-08-23 1990-07-03 Mare Creek Industries, Inc. Method for processing fine coal
US5522510A (en) * 1993-06-14 1996-06-04 Virginia Tech Intellectual Properties, Inc. Apparatus for improved ash and sulfur rejection
US6156083A (en) * 1998-02-05 2000-12-05 Tuboscope Coal reclamation systems
EP1892281A1 (de) * 2006-08-22 2008-02-27 S.C. Ceramica International S.r.l. Verfahren zur Herstellung eines Ersatzbrennstoffes für eine Verwendung in Kohlekraftwerken und/oder Müllverbrennungsanlagen und/oder Anlagen der Zementindustrie oder sonstigen Verbrennungsanlagen, in denen feste Brennstoffe verwendet werden
CN105772212A (zh) * 2016-04-25 2016-07-20 中国矿业大学 一种中等粘结性煤生产特种白水泥用煤方法
CN105772212B (zh) * 2016-04-25 2018-01-19 中国矿业大学 一种中等粘结性煤生产特种白水泥用煤方法
CN108855586A (zh) * 2017-05-12 2018-11-23 杨林 一种浮游选煤的联合机组
CN110961241A (zh) * 2019-11-05 2020-04-07 乌拉特中旗毅腾矿业有限责任公司 一种高效环保浮选入料工艺及其筛分装置
US20240253060A1 (en) * 2023-01-30 2024-08-01 Somerset International Finance Designated Activity Company Methods and systems for classification and recovery
WO2024161307A1 (en) * 2023-01-30 2024-08-08 Somerset International Finance Designated Activity Company Methods and systems for classification and recovery
CN116294533A (zh) * 2023-03-15 2023-06-23 中国矿业大学 一种多能量场梯级处理智能化决策的气化细渣脱水方法
CN116294533B (zh) * 2023-03-15 2024-05-17 中国矿业大学 一种多能量场梯级处理智能化决策的气化细渣脱水方法
US12275672B2 (en) 2023-03-15 2025-04-15 China University Of Mining And Technology Methods, systems for dehydrating gasification fine slags, and media thereof

Also Published As

Publication number Publication date
CA920809A (en) 1973-02-13
FR2098008A5 (enrdf_load_stackoverflow) 1972-03-03
BE768877A (fr) 1971-11-03
DE2134436A1 (de) 1972-01-13
GB1288016A (enrdf_load_stackoverflow) 1972-09-06

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