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EP0157307B1 - Gerät zum Herstellen einer hoch konzentrierten Kohlesuspension - Google Patents

Gerät zum Herstellen einer hoch konzentrierten Kohlesuspension Download PDF

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Publication number
EP0157307B1
EP0157307B1 EP19850103355 EP85103355A EP0157307B1 EP 0157307 B1 EP0157307 B1 EP 0157307B1 EP 19850103355 EP19850103355 EP 19850103355 EP 85103355 A EP85103355 A EP 85103355A EP 0157307 B1 EP0157307 B1 EP 0157307B1
Authority
EP
European Patent Office
Prior art keywords
mill
coal
slurry
high concentration
chamber
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.)
Expired
Application number
EP19850103355
Other languages
English (en)
French (fr)
Other versions
EP0157307A2 (de
EP0157307A3 (en
Inventor
Ryuichi Kaji
Keizou Ohtsuka
Yasushi Muranaka
Hideo Kikuchi
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.)
Hitachi Ltd
Mitsubishi Power Ltd
Original Assignee
Babcock Hitachi KK
Hitachi Ltd
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
Application filed by Babcock Hitachi KK, Hitachi Ltd filed Critical Babcock Hitachi KK
Publication of EP0157307A2 publication Critical patent/EP0157307A2/de
Publication of EP0157307A3 publication Critical patent/EP0157307A3/en
Application granted granted Critical
Publication of EP0157307B1 publication Critical patent/EP0157307B1/de
Expired legal-status Critical Current

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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, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L1/00—Liquid carbonaceous fuels
    • C10L1/32—Liquid carbonaceous fuels consisting of coal-oil suspensions or aqueous emulsions or oil emulsions
    • C10L1/326—Coal-water suspensions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/04—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls with unperforated container
    • B02C17/06—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls with unperforated container with several compartments

Definitions

  • the present invention relates to an apparatus for preparing coal slurry, wherein fine powder of coal is mixed with a liquid to form a slurry of such a high concentration as to permit transportation and direct burning in a furnace.
  • a transportation method has been known in which powder of a solid material is mixed with a liquid to form a slurry which is easy to handle and transport.
  • proposals are made to improve the efficiency of transportation of coal by using the slurry transportation method.
  • the coal concentration in the slurry is preferably high.
  • coal slurry having high concentration can be directly burnt as it is, without necessitating removal of the liquid after the transportation. For these reasons, various attempts have been made to develop a method for preparation of coal slurry having a high concentration and a low viscosity of such a level as to allow transportation by pipelines.
  • the main function of the additive is that the additive adsorbed by the particle surfaces improves the wettability of the coal to the liquid thereby enhancing the dispersibility of the coal particles.
  • the preparation of coal slurry having high concentration and large fluidity essentially requires both an appropriate particle size distribution and application of a suitable additive.
  • the preparation of coal slurry by such a technique is usually carried out by means of a ball mill as suggested, for example, in the above-mentioned US-A-4,282,006.
  • the ball mill has a cylindrical drum which is supported rotatably.
  • the drum is provided at its one end with a coal feed port and with a slurry outlet port at its other end.
  • a multiplicity of metallic balls for finely crushing the coal into particles are charged in the drum.
  • coarse particles of coal which have been crushed by a coarse crusher (not shown) are fed continuously into the rotating drum through the coal feed port.
  • the coal particles are then finely crushed by the balls and are mixed with a liquid such as to form a slurry which is then discharged through the slurry outlet port.
  • the slurry as the mixture of the coal particles, liquid and additive has a fluidity sufficiently high to allow the crushing balls to move freely in the slurry thus enhancing the chance of collision between the coal particles and the balls.
  • the coal particles in the region near the coal feed port generally have large particle sizes, so that the particle size distribution suitable for the coal slurry of high concentration is failed in a certain region within the mill.
  • the fluidity of the slurry as the mixture of the coal particles, liquid and the additive may be lowered to reduce the efficiency of crushing the coal.
  • GB-A-2 112 807 discloses a process for preparing a coal slurry which comprises the steps of a) coarsely crushing coal in a coarse crusher, b) passing through a sieve which selects the coarser fraction to be passed through a dry ball-mill, c) mixing the coal fractions coming from the dry ball-mill and directly from the sieve, respectively, d) passing the mixture through a wet ball mill in which water and dispersant are added thereto in order to obtain a highly concentrated slurry of coal particles having a specific particle size distribution.
  • the step b) may be omitted if more dispersant is used.
  • an object of the invention is to provide an apparatus for preparing coal slurry of high concentration with minimized consumption of additive.
  • the present inventors have made an intense study for developing a technique for preparation of coal slurry having high concentration.
  • the present inventors have tried a method in which coal particles in various mills are mixed to allow an adjustment of particle size distribution and water and an additive are added to the coal particles of the adjusted particle size distribution such as to form a slurry.
  • the inventors have found that the slurry prepared by this method exhibits a viscosity which is much lower than that of the slurry prepared by the conventional mill with the addition of the same quantities of water and additive.
  • the inventors found also that the above-mentioned preparation method permits a reduction of the additive consumption down below a half of that in the conventional process for attaining the same level of viscosity and concentration.
  • the present invention provides an apparatus for preparing a coal slurry of a high concentration having a substantially cylindrical mill supported rotatably, pulverizing balls charged in said mill, a coal feed port provided on one end of said mill and adapted for continuously supplying coarsely crushed coal into said mill therethrough, a slurry outlet port provided on the other end of said mill, and a liquid supply pipe for continuously supplying a liquid and an additive into said mill, characterized by at least one partition wall provided in said mill and disposed substantially normally to the axis of said mill such as to divide the space in said mill into a plurality of chambers, said partition wall being provided in the center thereof with a passage hole through which the adjacent chambers are communicated, the size of said passage hole being smaller than that of the slurry outlet port and the lowest portion of said passage hole being higher than the lowest portion of the slurry outlet port, said pulverizing balls being charged in said chambers, and said liquid supply pipe being communicated with the chamber adjacent to said slurry outlet port.
  • said pulverizing balls charged in said chamber adjacent to said coal feed port have a size which is greater than that of said pulverizing balls in said chamber adjacent to said slurry outlet port.
  • Fig. 1 illustrates an invented apparatus for preparing a coal slurry of a high concentration.
  • coal in a silo 18 is fed by a feeder 20 to a coarse crusher 22 so as to be coarsely crushed by the latter, and the thus coarsely crushed coal is sent to a hopper 24.
  • the crushed coal in the hopper 24 is fed continuously by a feeder 26 into a mill 10 through a coal feed port 12 formed in one end of the mill 10.
  • the mill 10 has a partition wall 28 which is normal to the axis of the mill 10.
  • the partition wall 28 divides the space in the mill into two sections or chambers: namely, a first mill chamber 30 and a second mill chamber 32.
  • the first and second mill chambers are communicated with each other through a passage hole 34 formed in the partition wall 28.
  • the mill 10 is provided with a slurry outlet port 14 to which is led a liquid supply pipe 36.
  • the liquid supply pipe 36 is connected, respectively, to a liquid tank 46 and an additive tank 48, through pipes 38 and 40 which are provided with pumps 42 and 44.
  • a slurry pipe 50 connected to the slurry outlet port 14 is arranged such that the slurry is put into the slurry tank 54 through a screen 52.
  • the coal which have been checked by the screen 52 are dried and returned to the coal feed port 12 of the mill 10 by a suitable means 56 such as a conveyor.
  • the coal feed port 12 and the slurry outlet port 14 are formed in axial hubs on respective axial end surfaces of the mill 10, and is supported at these hubs by support members 58, 60 through respective bearings.
  • the mill 10 is provided on the outer peripheral surface thereof with a gear 62 which meshes with a gear 68 fixed to the shaft 66 of a motor 64.
  • the first mill chamber 30 and the second mill chamber 32 of the mill 10 are charged with metal balls 70 and 72.
  • the balls 72 in the second mill chamber 32 have a smaller size than the balls 70 in the first mill chamber 32, so that the coal pulverized in the first chamber is further pulverized into smaller size upon collision with the balls 72 in the second mill chamber 32.
  • the passage hole 34 is formed in the central portion in of the partition wall 28 and has a size which is greater than that of the coal feed port 12 but smaller than that of the slurry discharge port 14.
  • the liquid supply pipe 36 led to the slurry outlet port 14 is extended into the second mill chamber 32 nearly to the partition wall 28.
  • the mill 10 is rotated about its axis as the gear 62 on its peripheral surface is driven by the motor 64 through the shaft 66 and the gear 68.
  • the coal in the coal silo 18 is coarsely crushed by the coarse crusher 22 and is fed continuously to the coal feed port 12 of the mill 10 through the hopper 24 and by means of the feeder 26.
  • the thus fed coal is introduced into the first mill chamber 30 in which it is pulverized in a dry condition upon collision with the balls 70 as a result of rotation of the mill 10, and is progressively moved towards the partition wall 28 while being pulverized into smaller sizes gradually, and is moved into the second mill chamber 32 through the passage hole 34.
  • the liquid such as water or an oil in the liquid tank 46 and in the additive tank 48 are forwarded by respective pumps 42 and 44 at constant rates such as to form a mixture liquid which is supplied to the portion of the second mill chamber 32 near the partition wall 28.
  • the pulverized coal introduced into the second mill chamber 32 is further pulverized by the balls 72 into smaller sizes, while being mixed with the mixture liquid coming from the liquid supply pipe 36, thus forming a coal slurry which is then discharged to the screen 52 through the slurry outlet port 14 by way of the slurry pipe 50.
  • the slurry which has passed the screen 52 is stored in the slurry tank 54.
  • the unpulverized large particles of coal are arrested by the screen 52 and are dried and returned to the coal feed port 12 by a suitable conveyor means 56.
  • the particle size distribution of the slurry thus prepared is determined optimumly in view of factors such as the kind of coal, rotation speed of the mill, sizes of the mill chambers, sizes of the balls 70, 72, quantity of balls, pulverizing time, and so on.
  • the pulverization in the first mill chamber 30 is conducted to such an extent as to permit an easy formation of the slurry in the second mill chamber.
  • the pulverization in the first mill chamber is effected such that the coal particles introduced into the second mill chamber contains fine particles of sized below 311m.
  • Coal was coarsely crushed into particles of sizes less than 5 mm and was changed into coal-water slurry of high concentration by the following process which employed the mill as shown in Fig. 2.
  • the mill 10 was made from stainless steel, in a cylindrical form having an inside diameter of 500 mm and a length of 1010 mm.
  • the passage hole formed in the center of the partition wall had a diameter of 200 mm.
  • the first and second mill chambers 30 and 32 had lengths of 700 mm and 300 mm, respectively.
  • the first mill chamber 30 was charged with 3000 pieces of stainless steel balls of 20 mm dia., while the second mill chamber 32 was charged with 1000 pieces of the same ball. While rotating the mill at 40 rpm, the coarsely crushed coal was fed into the mill through the coal feed port 12 at a constant rate of 10 kg per hour.
  • mixture of water and a cation surfactant was supplied into the second mill chamber 32 through the liquid supply pipe 36 at a constant rate of 5.38 litres per hour, while varying the surfactant content.
  • the coal was supplied to the portion in the first mill chamber near the coal feed port 12, while the water containing the surfactant was charged to the portion of the second mill chamber near the partition wall 28, such that the coal is sufficiently pulverized within the period of its stay in the mill.
  • the coal slurry prepared by this process showed a coal concentration of 65 wt%. Viscosities of different coal slurries prepared with different additive contents were measured by a rotary viscometer, in order to examine the relationship between the quantity of the additive, i.e., surfactant, and the viscosity.
  • coal slurries were prepared under the same condition using a mill which is identical to that used in the slurry preparation of the invention except that the partition wall 28 is removed, and the relationship between the quantity of the additive and the viscosity was examined.
  • the results of the tests are shown in Fig. 3 from which it will be understood that the slurry preparation method in accordance with the invention permits the quantity of the additive to be reduced almost to a half of that required in the conventional slurry preparation method for attaining the same level of viscosity of the slurry. This means that the cost for the preparation of coal slurry having high concentration can be reduced remarkably.
  • a coal slurry was prepared by the same apparatus as that used in Example 1 under the same pulverizing condition as Example 1 except that the rate of feed of coarsely crushed coal was increased to 14 kg per hour and that water containing 0.3 wt% of a cation surfactant with respect to coal was charged into the second mill chamber 32 through the liquid supply pipe 36 at a rate of 5.38 litres per hour.
  • the thus prepared coal slurry showed a concentration of 72.2 wt%.
  • the viscosity of the slurry was measured by the same method as Example 1 and a high fluidity of about 1.8 Pa S was confirmed.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Food Science & Technology (AREA)
  • Liquid Carbonaceous Fuels (AREA)
  • Crushing And Grinding (AREA)

Claims (2)

1. Vorrichtung zur Herstellung einer hochkonzentrierten Kohlesuspension mit einer praktisch zylindrischen, drehbar gelagerten Mühle (10), in der Mühle (10) vorhandenen Mahlkugeln (70, 72), einer Kohlezufuhröffnung (12) an einem Ende der Mühle (10), die für die kontinuierliche Zufuhr von grob zerkleinerter Kohle in die Mühle (10) angepaßt ist, einer Suspensionsauslaßöffnung (14) am anderen Ende der Mühle (10) und einem Rohr (36) für die kontinuierliche Zufuhr einer Flüssigkeit und eines Zusatzmittels in die Mühle (10), gekennzeichnet durch mindestens eine Trennwand (28) in der Mühle (10), die im wesentlichen senkrecht zur Achse der Mühle (10) angeordnet ist, so daß der Raum in der Mühle (10) in mehrere Kammern (30, 32) geteilt wird, wobei die Trennwand (28) in der Mitte eine Öffnung (34) aufweist, durch die benachbarte Kammern (30, 32) kommunizieren, die Öffnung (34) kleiner als die Suspensionsauslaßöffnung (14) und der tiefste Teil dieser Öffnung (34) höher als der tiefste Teil der Suspensionsauslaßöffnung (14) ist, die Mahlkugeln (70, 72) sich in diesen Kammern (30, 32) befinden und das Flüssigkeitszufuhrrohr (36) mit der der Suspensionsauslaßöffnung (14) benachbarten Kammer (32) kommuniziert.
2. Vorrichtung zur Herstellung einer hochkonzentrierten Kohlesuspension nach Anspruch 1, in der die Mählkugeln (70) in der der Kohlezufuhröffnung (12) benachbarten Kammer (30) größer als die Mahlkugeln (72) in der der Suspensionsauslaßöffnung (14) benachbarten Kammer (32) sind.
EP19850103355 1984-03-23 1985-03-22 Gerät zum Herstellen einer hoch konzentrierten Kohlesuspension Expired EP0157307B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP5587384A JPS60199099A (ja) 1984-03-23 1984-03-23 高濃度石炭スラリ−の製造方法及び装置
JP55873/84 1984-03-23

Publications (3)

Publication Number Publication Date
EP0157307A2 EP0157307A2 (de) 1985-10-09
EP0157307A3 EP0157307A3 (en) 1986-02-05
EP0157307B1 true EP0157307B1 (de) 1988-05-25

Family

ID=13011207

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850103355 Expired EP0157307B1 (de) 1984-03-23 1985-03-22 Gerät zum Herstellen einer hoch konzentrierten Kohlesuspension

Country Status (4)

Country Link
EP (1) EP0157307B1 (de)
JP (1) JPS60199099A (de)
AU (1) AU553418B2 (de)
DE (1) DE3562928D1 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ATA108786A (de) * 1986-04-23 1989-07-15 Voest Alpine Ag Kugelrohrmuehle
CN106369937B (zh) * 2016-11-01 2019-06-04 兖矿集团有限公司 一种煤泥干燥系统及其干燥工艺

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1507650C3 (de) * 1965-05-04 1973-10-04 F. L. Smidth & Co. A/S, Kopenhagen Zerkleinerungsschlammtrommel
JPS5896690A (ja) * 1981-12-03 1983-06-08 Electric Power Dev Co Ltd 石炭の高濃度スラリ−の製造方法

Also Published As

Publication number Publication date
JPS60199099A (ja) 1985-10-08
EP0157307A2 (de) 1985-10-09
AU553418B2 (en) 1986-07-17
EP0157307A3 (en) 1986-02-05
DE3562928D1 (en) 1988-06-30
AU4022285A (en) 1985-09-26

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