US3512723A - Installation for simultaneously drying pulverising and grading granular materials - Google Patents

Installation for simultaneously drying pulverising and grading granular materials Download PDF

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Publication number
US3512723A
US3512723A US740381A US3512723DA US3512723A US 3512723 A US3512723 A US 3512723A US 740381 A US740381 A US 740381A US 3512723D A US3512723D A US 3512723DA US 3512723 A US3512723 A US 3512723A
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United States
Prior art keywords
pulverised
installation
pulverising
fluidised
drying
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Expired - Lifetime
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US740381A
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English (en)
Inventor
Jacques A Geoffroy
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Charbonnages de France CDF
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Charbonnages de France CDF
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C13/00—Disintegrating by mills having rotary beater elements ; Hammer mills
    • B02C13/13—Disintegrating by mills having rotary beater elements ; Hammer mills with horizontal rotor shaft and combined with sifting devices, e.g. for making powdered fuel
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
    • C10B57/00—Other carbonising or coking processes; Features of destructive distillation processes in general
    • C10B57/08—Non-mechanical pretreatment of the charge, e.g. desulfurization
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F26—DRYING
    • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
    • F26B3/00—Drying solid materials or objects by processes involving the application of heat
    • F26B3/02—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air
    • F26B3/06—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried
    • F26B3/08—Drying solid materials or objects by processes involving the application of heat by convection, i.e. heat being conveyed from a heat source to the materials or objects to be dried by a gas or vapour, e.g. air the gas or vapour flowing through the materials or objects to be dried so as to loosen them, e.g. to form a fluidised bed

Definitions

  • a zone for homogenising the flow of hot gases issuing from the combustion chamber
  • a drying zone wherein the product to be treated is introduced
  • a pulverising zone wherein the product formed a fluidized layer and is subjected to the impact of a pulverisor
  • the present invention relates to an improved apparatus for simultaneously pulverising, grading and drying or preheating non-agglutinant granular materials at the drying or preheating temperature.
  • the fluid layer is fed with material to be treated by pneumatic transport of the material by means of hot gases arriving in the fluidised layer beneath the moving portion of the cage type pulverisor.
  • pneumatic transport of the material by means of hot gases arriving in the fluidised layer beneath the moving portion of the cage type pulverisor.
  • An advantage of this device is that gases at temperatures higher than those occurring in a conventional drying or preheating in a fluidised bed can be used and this enables the contact time of the very fine products with the gases which propel them to be reduced.
  • the present invention concerns an improved installation for simultaneously pulverising in a fluidised bed, grading and drying or reheating non-agglutinant granular materials at the temperature of the drying or preheating treatment, essentially characterised in that it comprises in combination:
  • a vertical hot gas inlet conduit connected to the base of the fluidisation chamber, the section of the conduit being smaller than that of the fluidisation chamber and composed of two portions connected by a convergent-divergent portion;
  • a horizontally disposed pulzerisor having hammers and being located within the zone of the vertical fluidisation chamber where the products form a fluidised suspension
  • An evacuation conduit connected to the upper part of the vertical fluidisation chamber and leading into a pneumatic transport duct;
  • a dust removing installation having suction cyclones, cognected to the outlet of the pneumatic transport duct;
  • the hammers of the pulverisor are constituted by bars of constant thickness
  • the feed means for the material to be pulverised are constituted by a band screw in which the width of the band increases in the direction of movement of the materials;
  • the evacuation conduit is provided at its base with a connecting element, the section of which converges in an upward vertical direction;
  • the height of the base of the connecting element of the evacuation conduit with respect to the fluidised bed is adjustable
  • the means for producing a constant flow of hot gases are constituted in known manner by a combustion cham her in which a fuel is burned under neutral combustion;
  • the means for maintaining the temperature of the fluidised layer at a constant value are constituted by a variable speed motor driving the feed screw for the material to be pulverised, a temperature sensing device immersed in the fluidised layer and a device known per se for causing the rotational speed of the motor driving the feed screw to be varied according to the temperature variation in the fluidised layer.
  • the means for maintaining the fluidised layer at a constant temperature are constituted by a temperature sensing device immersed in the fluidised layer and a device known per se to cause the flow of fuel to vary inversely as the temperature of the fluidised layer.
  • FIG. 1 is a general view of the installation of the invention
  • FIG. 2 is a sectional view to a larger scale of the zone in which pulverisation, drying and grading proper of the materials to be treated are carried out;
  • FIGS. 3 and 4 are two detail views showing the movable portion of the hammer pulverisor in vertical and horizontal section respectively.
  • FIG. 5 is a view in partial section of the stufling box installed at each end of the shaft driving said movable portion.
  • the installation of the present invention shown by way of example in the drawings comprises a vertical chamber of rectangular transverse section designated by the general reference 1, which chamber is connected at its lower portion to a combustion chamber 2 and, at its upper portion, to a dust removing installation having cyclones 3 and 4.
  • a zone 5 for homogenising the flow of hot gases issuing from the combustion chamber 2 having the shape, at its upper portion, of a converging-diverging neck 6 whose outlet section is smaller than the inlet section so as to increase the speed at which the hot fumes rise.
  • a pulverising zone 10 whose transverse section is greater than the transverse section of the drying zone 7 such that, as the speed of the gases decreases therein, the mass of products to be pulverised propelled by the gases assumes the form of a fluidised layer 11.
  • the movable portion 12 of an impact pulverisor, described hereinafter, is installed in the fluidised layer 11.
  • the conveyor screw is preferably a band screw, the width of the band increasing in the direction of flow of the products.
  • This type of conveyor screw is described in French Pat. No. 1,483,954 corresponding to US. application Ser. No. 641,900 filed May 29, 1967, and now abandoned. It enables the products to be pulverised to be continuously extracted over the whole length of the base of the hopper 8, whilst at the same time avoiding the formation of curved cavities within the hopper and preventing the products from sticking to the walls.
  • the products to be pulverised are propelled and predried by the rising current of hot gases.
  • the speed of the gases decreases in the pulverising zone 10 because of the widening of the conduit, and the mass of products to be pulverised forms a fluidised layer 11 if the ratio of the flow of gases to the section of the conduit in the pulverising zone is calculated as a function of the granulometry of the products to be pulverised.
  • the hammers 16 are preferably constituted by simple bars of uniform rectangular transverse section as shown in FIGS. 3 and 4.
  • the driving shaft 17 of the movable part of the pulverisor is mounted by means of a known system of bearings and air swept stufiing boxes (FIG. 5) in order to protect the seals 18 from contact with atmospheric dust and to prevent rapid wear of the seals and of the shaft 17 in the vicinity of the bearings.
  • the zone of the vertical chamber 1 located above the fluidised bed is connected to the transport duct 19, leading to the dust removing installation, by means of a conduit 20 having at its lower portion a connecting element 21 which converges in the upward vertical direction.
  • the grading zone 13 is defined by the upper level of the fluidised layer 11 and the base of the connecting element 21.
  • the non-pulverised or insufiiciently pulverised particles in the fluidised layer 11 and propelled by the gases leaving the fluidised layer separate out and fall back into the fluidised layer 11 where they are subjected to additional pulverisation, while the dried and pulverised particles which have attained the desired fineness are propelled pneumatically through the transport duct 19.
  • the return height i.e. the vertical distance H separating the upper level of the fluidised layer from the base of the connecting element 21, must be large enough to allow the large particles, ejected from the bed and whose speed of fall in the rising gases is greater than the speed of rise of the gases, to fall back.
  • the optimum height of the grading zone 13 is adjusted experimentally by altering the height of the lower end of the connecting element 21 with respect to the upper level of the fluidised layer, for example by altering the length of the conduit 20.
  • the pneumatic transport duct 19 takes the mixture of the gases and the dried and sufliciently pulverised products to the dust removing installation which has a first cyclone 3 and second cyclone 4.
  • the particles trapped by the two cyclones are led to their place of use by any known means which are not shown.
  • the quantity of hot combustion gases leaving the combustion chamber 2 may be regarded as constant, whatever may be the amount of fuel used.
  • the temperature of the combustion gases leaving the combustion chamber is maintained at a constant value by adjusting once and for all the amount of fuel as a function of the quantity of gases to be produced and thus of the quantity of combustive air, and the rate of introduction of the products to be pulverised is adjusted as a direct function of the temperature of the fluidised layer.
  • the apparatus in this case comprises a temperature sensing device 22 immersed in the fluidised layer 11, and a regulating device 23, known per se, causing the speed of rotation of the motor 24 driving the screw 9 to be varied in the same sense as the observed temperature variation.
  • the apparatus comprises a temperature sensing device 22 immersed in the fluidised layer, and a regulating device 25, of any known type, acting on a valve 26 in such a manner that the amount of fuel flowing increases when the temperature of the fluidised layer 11 fal s and vice-versa.
  • the replacement of worn elements on the movable part of the pulverisor (notably the hammers) is an easyoperation not requiring prolonged halting of the installation.
  • the apparatus of the invention was used to pulverise coal granules having the characteristics shown in the first line of the following table.
  • the installation operated for three hours with a flow (g) an evacuation conduit having a section smaller of coal of9t./h. 10 than that of the vertical fluidisation chamber and The temperature of the gases was 360 C. and the temperature of the fluidised layer was maintained at
  • the pulverising and grading zone had the following dimensions: 0.49 m. X 1 m. and the movable part of the pulverisor had a diameter of 0.90 m.
  • the speed under no load of the fumes in the pulverising zone was 3.6 m./s.
  • the return height H was 2 m.
  • a vertical fluidisation chamber of substantially uniform rectangular section having a base in the form of a pyramid diverging in an upward direction and connected at its lower part to the top of said vertical hot gaseous fluid circulation conduit;
  • the outlet section of said pyramidal base is greater than the section of said vertical hot gaseous fluid circulation conduit and causes the materials to be pulverised to form a fluidised suspension in said vertical fluidisation chamber;
  • the means for maintaining the temperature of the fluidised layer at a substantially constant value is constituted by a variable speed motor driving the means for feeding the material to be pulverised, by a temperature sensing device immersed in the fluidised layer and by a device for causing the speed of rotation of said motor to vary as a direct function of temperature variations in the fluidised layer.
  • the means for maintaining the temperature of the fluidised layer at a substantially constant value is constituted by a temperature sensing device immersed in the fluidised layer and by a device for causing the fuel flow to vary inversely as temperature variations in the fluidised layer.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Food Science & Technology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Microbiology (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Drying Of Solid Materials (AREA)
  • Crushing And Pulverization Processes (AREA)
US740381A 1967-06-30 1968-06-26 Installation for simultaneously drying pulverising and grading granular materials Expired - Lifetime US3512723A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR112724 1967-06-30

Publications (1)

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US3512723A true US3512723A (en) 1970-05-19

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Country Status (9)

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US (1) US3512723A (de)
JP (1) JPS5432976B1 (de)
AT (1) AT281717B (de)
BE (1) BE717404A (de)
DE (1) DE1767913A1 (de)
FR (1) FR1555546A (de)
GB (1) GB1193761A (de)
LU (1) LU56378A1 (de)
NL (1) NL6809141A (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4270762A (en) * 1977-05-03 1981-06-02 Coaltek Corporation Disperser seal and method
USRE30778E (en) * 1976-12-01 1981-10-20 Pennsylvania Crusher Corporation Crusher-dryer and method of crushing
US4382777A (en) * 1980-04-04 1983-05-10 Charbonnages De France Process for modifying the properties of a swelling coal, an installation for carrying out the process and a chamber for treatment of coal by fluidization and crushing

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2305234A1 (fr) * 1975-03-24 1976-10-22 Charbonnages De France Installation de traitement combine de broyage, triage et sechage de materiaux granuleux
DE2907481A1 (de) * 1979-02-26 1980-08-28 Kloeckner Humboldt Deutz Ag Verfahren und vorrichtung zur trocknung feinkoerniger stoffe
GB9317849D0 (en) * 1993-08-27 1993-10-13 Bpb Industries Plc Improvements in calcination

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1814560A (en) * 1929-01-23 1931-07-14 Int Comb Eng Corp Fuel preparing and handling system
US1875817A (en) * 1929-02-12 1932-09-06 Peabody Engineering Corp Apparatus for pulverizing materials
US2075506A (en) * 1935-06-13 1937-03-30 Raymond Brothers Impact Pulver Drying apparatus
US3050018A (en) * 1959-03-24 1962-08-21 Babcock & Wilcox Co Pulverizer control system
FR1357803A (fr) * 1963-02-28 1964-04-10 Charbonnages De France Appareil de séchage, de broyage et de triage simultanés des matériaux granuleux
FR1483954A (fr) * 1966-04-28 1967-06-09 Charbonnages De France Dispositif de manutention par vis

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1814560A (en) * 1929-01-23 1931-07-14 Int Comb Eng Corp Fuel preparing and handling system
US1875817A (en) * 1929-02-12 1932-09-06 Peabody Engineering Corp Apparatus for pulverizing materials
US2075506A (en) * 1935-06-13 1937-03-30 Raymond Brothers Impact Pulver Drying apparatus
US3050018A (en) * 1959-03-24 1962-08-21 Babcock & Wilcox Co Pulverizer control system
FR1357803A (fr) * 1963-02-28 1964-04-10 Charbonnages De France Appareil de séchage, de broyage et de triage simultanés des matériaux granuleux
FR1483954A (fr) * 1966-04-28 1967-06-09 Charbonnages De France Dispositif de manutention par vis

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
USRE30778E (en) * 1976-12-01 1981-10-20 Pennsylvania Crusher Corporation Crusher-dryer and method of crushing
US4270762A (en) * 1977-05-03 1981-06-02 Coaltek Corporation Disperser seal and method
US4382777A (en) * 1980-04-04 1983-05-10 Charbonnages De France Process for modifying the properties of a swelling coal, an installation for carrying out the process and a chamber for treatment of coal by fluidization and crushing

Also Published As

Publication number Publication date
FR1555546A (de) 1969-01-31
JPS5432976B1 (de) 1979-10-17
AT281717B (de) 1970-05-25
NL6809141A (de) 1968-12-31
DE1767913A1 (de) 1971-09-30
GB1193761A (en) 1970-06-03
LU56378A1 (de) 1969-04-25
BE717404A (de) 1968-12-30

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