CA3182146A1 - Method and device for dry granulation - Google Patents
Method and device for dry granulationInfo
- Publication number
- CA3182146A1 CA3182146A1 CA3182146A CA3182146A CA3182146A1 CA 3182146 A1 CA3182146 A1 CA 3182146A1 CA 3182146 A CA3182146 A CA 3182146A CA 3182146 A CA3182146 A CA 3182146A CA 3182146 A1 CA3182146 A1 CA 3182146A1
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- Canada
- Prior art keywords
- fluidized
- fluidized bed
- bed
- granulator
- particles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/16—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic by suspending the powder material in a gas, e.g. in fluidised beds or as a falling curtain
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B3/00—General features in the manufacture of pig-iron
- C21B3/04—Recovery of by-products, e.g. slag
- C21B3/06—Treatment of liquid slag
- C21B3/08—Cooling slag
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/02—Physical or chemical treatment of slags
- C21B2400/022—Methods of cooling or quenching molten slag
- C21B2400/026—Methods of cooling or quenching molten slag using air, inert gases or removable conductive bodies
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/02—Physical or chemical treatment of slags
- C21B2400/022—Methods of cooling or quenching molten slag
- C21B2400/028—Methods of cooling or quenching molten slag with the permanent addition of cooled slag or other solids
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/05—Apparatus features
- C21B2400/052—Apparatus features including rotating parts
- C21B2400/054—Disc-shaped or conical parts for cooling, dispersing or atomising of molten slag rotating along vertical axis
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/05—Apparatus features
- C21B2400/062—Jet nozzles or pressurised fluids for cooling, fragmenting or atomising slag
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21B—MANUFACTURE OF IRON OR STEEL
- C21B2400/00—Treatment of slags originating from iron or steel processes
- C21B2400/05—Apparatus features
- C21B2400/066—Receptacle features where the slag is treated
- C21B2400/068—Receptacle features where the slag is treated with a sealed or controlled environment
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
- Glanulating (AREA)
- Disintegrating Or Milling (AREA)
Abstract
The invention relates to a method for dry granulation of molten material, wherein particles produced from this material are cooled in at least one fluidised bed by means of process gas and, at least in the fluidised bed which the particles enter directly after they are produced, the process gas is fed into the fluidised bed in a plurality of separate zones. The invention also relates to a corresponding granulator and a signal processing device, a machine-readable program code, a storage medium for the program code and a computer program product therefor.
Description
Description Title of the invention Method and device for dry granulation Technical field The invention relates to a method for dry granulation of molten material and to a granulator.
Prior art Dry granulation of molten material is a technology under development for processing molten material into solid granules.
Molten material is, for example, molten metal or metallurgical slag, for example molten blast furnace slag - the method is then also called dry slag granulation DSG and is described, for example, in EP2747920B1. In this context, dry means that the molten material does not come into direct contact with liquid water during granulation - this is, for example, a contrast to methods which are conventionally used in industry for granulating blast furnace slag, in which the molten slag is introduced into a stream of water. The granulator is a vessel which is bounded by a casing and which has a slag feed, a gas feed for the process gas and an exhaust line for heated process gas - also referred to as process exhaust gas in the context of this application - for example air - also referred to as process air. The molten material, for example liquid slag, is applied to an atomization unit located in the casing of the granulator;
this is, for example, a rapidly rotating unit, known as a rotary atomizer; something like this is shown, for example, in EP2747920B1. As a result of the forces which occur, the molten material is torn into fine droplets and thrown outward. These fine, initially still molten droplets are cooled in the Date Recue/Date Received 2022-11-03 granulator and solidify, this being accomplished, for example, by the process gas and by impingement on granulator surfaces -which may be cooled - for example the water-cooled casing of the granulator, as a result of which solid particles, referred to here as granules, are formed, which are then removed from the granulator. According to a known procedure, liquid or partially solidified - that is to say partially liquid and partially solidified - droplets fall downward in the granulator, after leaving the rotary atomizer and subsequently striking the casing of the granulator, into a fluidized bed. In the fluidized bed, the particles are continuously solidified. There is a flow of process gas counter to gravity through the fluidized bed. The particles are thereby placed in a fluidized state, and the quantity through which the gas flows takes on virtually fluid-like properties, this also being referred to as fluidizing and being a known principle in process engineering. Starting from a state known as a fixed bed, in which the process gas flows through a bulk material without fluidizing it, fluidization begins at a defined point as the process gas velocity increases.
The type of fluidization present in a fluidized bed depends essentially on the gas velocity, gas density, and also on the particle bulk density, the shape, and the particle size distribution of the particles. The term fluidized bed is equivalent to the term fluid bed; the two terms are used as synonyms in the present application. The transition from a fixed bed to a fluidized bed takes place at the fluidization point.
The granulator comprises devices for introducing process gas, which is intended to form a fluidized bed of particles.
Such fluidized-bed cooling is advantageous because it is possible in a fluidized bed, owing to the high convection and the volume/surface area ratios of the particles, for a large amount of heat to be rapidly dissipated into the process gas and carried away by the flow of process gas. In addition, the movement of a fluidized bed ensures that freshly arriving Date Recue/Date Received 2022-11-03 particles - which are still particularly hot and may thus be at least partially soft and sticky and therefore tend to agglomerate - do not remain at the surface of the fluidized bed but are moved to other points or mixed into the interior of the fluidized bed. As a result, the probability of several droplets which arrive successively at the surface of the fluidized bed, or still hot, not fully solidified - and therefore sticky -particles coming into contact with one another and agglomerating is almost completely eliminated. Agglomeration of the particles would promote growth into larger, heavier particles, which would seriously impair the process.
Dry granulation with fluidized-bed cooling offers the possibility of recovering the heat transferred to the process gas during the cooling of the particles from the process gas.
Conventional granulation technologies based on fluidized-bed cooling for dry granulation of molten material, such as, for example, liquid blast furnace slag, with rotary atomizers and exploitation of impingement on the casing have a large diameter since, in order to avoid agglomeration of liquid and/or partially solidified droplets and/or fully solidified particles during flight from the rotary atomizer to the casing or after impingement on the casing, the selected clearance of the casing - which is generally arranged in a rotationally symmetrical manner with respect to the rotary atomizer and is therefore as a rule round in cross section - has to be sufficiently large. A
relatively large clearance leads to fanning out of the flow of droplets or particles coming from the rotary atomizer, with the result that the droplets or particles fly less close to one another or are less close to striking one another. This reduces the risk of agglomeration during flight or upon impact.
Agglomeration can occur on impact, for example, if completely or partially liquid particles are deformed on impact and, as a result, come into contact with adjacently impinging particles.
Date Recue/Date Received 2022-11-03 Since the particles fall downward after impinging on the casing, following the force of gravity, the size of the impingement region also affects the area of the fluidized bed, which must be present at least underneath the impingement region.
Furthermore, the area required for a desired cooling potential is also affected by the temperature, mass flow and thus heat input of the particles into the fluidized bed, and what gas velocity ranges are necessary for the size distribution of particles in order to maintain a fluidized bed. Given a limited maximum velocity of the gas flow, it will be necessary to enlarge the area of the fluidized bed for the purpose of increasing the quantity of gas which can be introduced into the fluidized bed at the maximum gas velocity in order, for example, to achieve a desired increased cooling effect.
The height of a fluidized bed is limited by the resulting pressure loss of the gas flowing up through it from below. This pressure loss, caused by the production of the fluidized bed state during flow-through, determines what pressure must be provided during introduction in order to maintain the gas flow necessary for the desired cooling effect. The higher the pressure to be applied, the higher the energy consumption for the introduction of the gas. The higher the fluidized bed, the greater the pressure loss. Structural conditions can also limit the achievable height of the fluidized bed.
Consequently, in conventional granulation technologies, based on fluidized-bed cooling, for dry granulation of molten material - such as, for example, blast furnace slag - with rotary atomizers, the ratio of area to height is relatively large in comparison with other methods which utilize fluidized beds for heat exchange and/or mass transfer, such as, for example, FINEM
fluidized-bed reduction.
Date Recue/Date Received 2022-11-03 However, with a large area and, at the same time, a small height of the fluidized bed, problems arise with such a dry granulation method. For example, local collapse of the fluidized bed can occur as a result of inhomogeneities in the granulation process, which, for example with respect to the cross section of the fluidized bed, cause non-rotationally symmetrical distribution of the particles falling from the casing; formation of hot spots as a result of poor horizontal mixing due to weak turbulence in this respect in the fluidized bed; and nonuniform fluidization, especially when starting up the fluidized bed. Such problems can greatly promote agglomeration because there may be local accumulation of droplets or hot, sticky particles that are not rapidly cooled to complete solidification. Excessively large agglomerates can impair the maintenance of the fluidized bed and require a halt in operations for their removal. In order to avoid problems due to nonuniform fluidization, the supply of process gas - or the supply of air when air is used as the fluidizing or cooling gas - to the fluidized bed has hitherto been provided with a pressure which allows the fluidized bed to be formed to a sufficiently great extent even in poorly fluidized regions. It is disadvantageous here that well fluidized regions are supplied with a pressure above the pressure required for them - this leads to higher energy consumption for the pressure-generating units and reduces the latitude for varying the gas flow through the fluidized bed. It also increases the quantity of process gas passed through these regions, and this is unfavorable for heat recovery from the process gas owing to a lower temperature.
Summary of the invention Technical problem Date Recue/Date Received 2022-11-03 One problem addressed by the present invention is therefore that of presenting apparatus and methods which at least partially reduce or solve such problems.
Technical solution This problem is solved by a method for dry granulation of molten material, wherein particles produced from this material are cooled in at least one fluidized bed by means of process gas, characterized in that, at least in that fluidized bed which the particles enter directly after they are produced, the process gas is fed into the fluidized bed in a plurality of separate zones.
The molten material originates from one or more mineralogical processes - such as the production of a rock melt in a cupola furnace for the production of mineral wool, also called rock wool - and/or from one - or more - metallurgical processes. The molten material is preferably molten metallurgical slag - i.e.
slag from a metallurgical process. It can also comprise mixtures of different types of slag.
These are, for example, slags resulting from reduction processes on ferrous materials for the production of iron, such as, for example, slags during the operation of blast furnaces or smelting reduction processes, such as, for example, COREM or FINEM; or they are slags produced during the melting of solid products - for example direct reduced iron (DRI) - from direct reduction processes - which can, for example, involve melting down DRI in a vessel - which is not, for example, an LD
steelworks converter for the production of crude steel - with resistance heating by electric current and/or by an electric arc, or melting down DRI in a steelworks converter, for example an LD steelworks converter.
Date Recue/Date Received 2022-11-03 These are, for example, slags produced in steelworks processes for the production of steel from iron, for example slag from the operation of LD (BOF), AOD, EAF. It is preferably slag from the production of pig-iron-like melt or of pig-iron melt - for example by means of smelting reduction processes, such as, for example, COREXC) or FINEXC) or blast-furnace processes -particularly preferably blast furnace slag. Another preferred option is slag from a DRI melting down process.
In the course of dry granulation, particles are produced from the molten material. The production of particles from the molten material is accomplished by means of an atomizer unit, preferably by means of a rotary atomizer. In this context, atomization means the generation of particles from the molten material. A rotary atomizer is based on the principle of applying liquid material to a rotating body, the rotation is transferred from the rotating body to the liquid, and droplets are released from the liquid as a result of centrifugal force, i.e. the liquid is atomized.
Here, the term particles includes liquid droplets, partially solidified particles - that is to say particles which are partially liquid and partially solid; for example particles which are solid on the outside and liquid on the inside - and fully solidified particles. Liquid, partially solidified and fully solidified particles may be sticky. Here, stickiness refers to the ability to adhere to or agglomerate with other particles produced during dry granulation.
The particles are formed from molten material. Molten material has a temperature above its melting point, and the particles accordingly contain more thermal energy than in the solid state.
Cooling is intended to solidify the particles to such an extent that there is no longer any tendency for agglomeration, due to Date Recue/Date Received 2022-11-03 stickiness, of significance for the operation of the fluidized bed.
In this context, dry granulation means that the molten material does not come into direct contact with liquid water during granulation. However, liquid water can contribute indirectly to cooling, for example if the casing of the granulator is water-cooled.
The particles produced during dry granulation are cooled by means of process gas in at least one fluidized bed.
They can therefore be cooled in one fluidized bed or in a plurality of fluidized beds; in the case of a plurality of fluidized beds, the particles pass through these in succession.
Feeding of the process gas into the fluidized bed in a plurality of separate zones can take place in one, some or all of these fluidized beds.
Since a fluidized bed is to be formed for intensive heat exchange, cooling is performed by means of gas, also referred to here as process gas. Air is preferably used as the process gas since it is readily available, and is here also referred to as process air. The fluidized bed is, for example, a turbulent fluidized bed or a slugging fluidized bed.
According to the invention, the process gas of at least that fluidized bed which the particles enter directly after they are produced is fed into the fluidized bed in a plurality of separate zones. By this is meant the first fluidized bed into which the particles enter after their formation; the phrase "directly after their formation" includes other processes taking place after formation, before the particles enter a fluidized bed for the first time - for example striking the casing before they fall down from the casing into the fluidized bed.
Date Recue/Date Received 2022-11-03 In contrast to a hitherto customary single feed, i.e. feed in a single zone, for example a distributor plate at the bottom of the vessel surrounding the fluidized bed, through which gas is fed in from a single feed - and thus at a single pressure -feeding does not take place in a single zone but in a plurality of zones. The separate zones adjoin one another and together cover the entire area of the fluidized bed. In the case of conventional feeding in a single zone, the area of the fluidized bed is covered by this single zone.
According to the invention, feeding is carried out in at least two zones, preferably in at least three zones, particularly preferably at least four zones. Gas can be fed in, for example, in two zones or in three zones or in four zones or in five zones or in six zones or in seven zones or in eight zones or in nine zones or in ten zones or in more than ten zones.
Advantageous effects of the invention The feeding, according to the invention, of the process gas into the fluidized bed in a plurality of separate zones makes it possible to set different conditions zone by zone, e.g. by open-loop and/or closed-loop control. For example, different pressures can be selected for the supplied process gas in different zones. For example, the volume flow - that is, the volume of process gas fed to the fluidized bed per unit of time - selected in different zones can be different. For example, the pressure and/or volume flow can be varied zone by zone, optionally independently of other zones. In contrast to conventional feeding in a single zone, it is thus possible to supply each zone in an optimum manner with process gas with respect to its requirements, for example in respect of pressure and/or volume flow - for example in an energy-optimal manner.
Differences between different regions of the fluidized bed with respect to fluidization can be automatically compensated for or Date Recue/Date Received 2022-11-03 brought about by corresponding zone-by-zone changes by the control system or by manual changing of the parameters by the operating personnel.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to compensate for differences in the bed height of the fluidized bed between different regions; such differences can occur, for example, as a result of asymmetrically distributed impingement on the casing and correspondingly asymmetrically distributed falling into the fluidized bed.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to compensate for differences in the temperature in the fluidized bed between different regions; such differences can occur, for example, as a result of asymmetrically distributed impingement on the casing and correspondingly asymmetrically distributed falling into the fluidized bed.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to compensate for differences in the extent of fluidization in the fluidized bed between different regions.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to bring agglomerates which have been deposited at the bottom of the fluidized bed in only one region into the fluidized state.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure in order to produce uniform process gas distribution in all regions of the fluidized bed; nonuniform air distribution can be brought about, Date Recue/Date Received 2022-11-03 for example, by blocking individual openings for feeding in process gas, and/or by different particle size distribution in the fluidized bed due to asymmetrically distributed impingement on the casing and correspondingly asymmetrically distributed falling into the fluidized bed in conjunction with poor horizontal mixing of the fluidized bed.
Zonal adjustability also offers the advantage that an increase in the quantity of process gas to eliminate irregularities is limited, this being advantageous for achieving the highest possible temperature of the process exhaust gas leaving the granulator. Heat recovery from this process exhaust gas is more efficient at higher temperatures. Thus, energy recovery from the process exhaust gas is possible in an efficient and economically viable manner even with the operation of fluidized beds that have a large area and large quantities of process gas as a result.
The process gas is fed into the fluidized bed in a plurality of separate zones, but the fluidized bed itself is not subdivided by devices, such as, for example, walls, into partial fluidized beds which together form the fluidized bed of the device for dry granulation - in this case, mixing would be inhibited, for example, and particles could stick. The fluidized bed is thus one in which process gas is fed in in a plurality of separate zones.
According to a preferred embodiment, in the method the volume flow and/or pressure of the process gas in at least two zones is/are subject to open-loop and/or closed-loop control independently of other zones.
Adaptation to local requirements in the fluidized bed is thereby made easier.
Date Recue/Date Received 2022-11-03 The pressure of the process gas means the pressure at which the process gas is supplied to the fluidized bed.
According to a preferred embodiment, in the method the height of the fluidized bed is determined over, preferably perpendicularly over, at least two zones.
This allows local differences to be detected; on this basis, countermeasures can be taken if necessary. Determination can take place directly - by height measurement - or indirectly -by calculation from measured variables of a different kind. The height of the fluidized bed in a region is determined, for example, on the basis of pressure measurement in the fluidized bed, for example at the bottom of the fluidized bed, in this region.
According to a preferred embodiment, in the method the temperature in the fluidized bed is determined over, preferably perpendicularly over, at least two zones. Determination can take place directly - by temperature measurement - or indirectly -by calculation from measured variables of a different kind. The temperature of the fluidized bed in a region is determined, for example, on the basis of measurements with a thermocouple or with a resistance thermometer. This provides information, for example, about the cooling requirement in this region of the fluidized bed or about the risk of agglomeration due to heat-induced viscosity or stickiness of the particles.
According to a preferred embodiment, in the method the intensity of the fluidized bed is determined over, preferably perpendicularly over, at least one of the zones. Determination can take place, for example, on the basis of measurements of the pressure in the fluidized bed, preferably in a locally fixed manner over the bottom of the fluidized bed, or evaluation of the time characteristic of the pressure development. This Date Recue/Date Received 2022-11-03 provides information, for example, about irregularities in the fluidized bed and the mixing, and the associated risk of formation of hot spots or of agglomerations or deviations from desired properties of the granules, such as, for example, bulk density and particle size distribution. The intensity of the fluidized bed is obtained from the time characteristic of the pressure in the fluidized bed or can be read out from it. There are various methods for determining the intensity. The following is a list of possibilities, although other methods of intensity evaluation are possible.
- Detection of the minimum (Min) and maximum (Max) pressure value occurring within a defined time period A. The difference between the maximum and the minimum is formed, and represents the intensity of the fluidized bed. The duration of the selected time period A is between 5 sec (seconds) and 5 min (minutes), preferably between 15 sec and 1 min.
- Detection of the minimum (Min) and maximum (Max) pressure value occurring within a defined time period B. The duration of the selected time period B is between 5 sec and min, preferably between 15 sec and 1 min. Determination of an average value of all recorded pressure measurements within a period of time C. The duration of the selected time period C is between 10 sec and 10 min, preferably between 1 min and 3 min. Time period B is in this case at the end of time period C, but fully within time period C.
Time period B is always shorter than or equal to time period C. The differences between the maximum and minimum pressure values and the average value are formed and give some insight into the intensity of the fluidized bed.
- Determination of a standard deviation - or similar methods of determining deviations - of the detected measured values for the pressure within a defined time period D. The duration of the selected time period D is between 5 sec and Date Recue/Date Received 2022-11-03 min, preferably between 15 sec and 1 min. The standard deviation represents the intensity.
The greater the value of the intensity, the greater the intensity of the fluidized bed. For example, if the pressure fluctuates sharply around an average value with respect to time within a defined time period, it is possible to refer to a high intensity and, if fluctuation is low, it is possible to refer to low intensity.
The features discussed, namely the height of the fluidized bed, the temperature in the fluidized bed, and the intensity of the fluidized bed, can be used for open-loop and/or closed-loop control of the method.
Closed-loop or open-loop control can be carried out, for example, in such a way that, at individual measuring points for determining height or temperature or intensity - or other parameters, deviations from average values or specifications for these parameters are detected as a result of monitoring. On this basis, for example, the volume flow of the process gas in a zone can be increased if the temperature in the fluidized bed over this zone is too high, or the volume flow can be reduced if the temperature is too low. The volume flow of the process gas in a zone can also be increased if the height of the fluidized bed over this zone is too great, in which case an excess of particles is transported away from the region by increased mixing, or the volume flow can be reduced if the height is too small. The volume flow of the process gas in a zone can also be increased if the intensity of the fluidized bed over this zone is too low, or the volume flow can be reduced if the intensity is too high.
The particles produced during dry granulation are cooled by means of process gas in at least one fluidized bed. They can therefore be cooled in one fluidized bed or in a plurality of Date Recue/Date Received 2022-11-03 fluidized beds; in the case of a plurality of fluidized beds, the particles pass through these in succession.
According to an advantageous embodiment of the method according to the invention, cooling is carried out in stages to a final temperature, first to a primary cooling temperature in that fluidized bed which the particles enter directly after they are produced, and then to the final temperature in at least one further fluidized bed.
According to one of many possible embodiments, at least in one of the further fluidized beds, process gas is fed in in a plurality of separate zones - that is to say, analogously to the feed into that fluidized bed which the particles enter directly after they are produced.
In respect of the feed or flow of the process gas, the further fluidized bed or beds can be arranged in series or in parallel with that fluidized bed which the particles enter directly after they are produced. A combination of in-series and parallel arrangement is also possible.
The fluidized bed which the particles enter directly after they are produced is also referred to here as the primary fluidized bed. When removed from this fluidized bed, the particles have what is referred to as the primary cooling temperature.
In one or more further fluidized beds, the particles are further cooled to a final temperature on removal from the last fluidized bed.
The particles are removed from the primary fluidized bed and introduced into a further fluidized bed - called the first downstream fluidized bed. The temperature of the particles on removal from the downstream fluidized bed is the first Date Recue/Date Received 2022-11-03 downstream temperature. If, after removal from the first downstream fluidized bed, the mixture is not introduced into a further fluidized bed, the first downstream temperature is the final temperature. If, after removal from the downstream fluidized bed, the mixture is introduced into a further fluidized bed - called the second downstream fluidized bed - the particles, after cooling in the second downstream fluidized bed, have the second downstream temperature when removed from the second downstream fluidized bed. If, after removal from the second downstream fluidized bed, the mixture is not introduced into a further fluidized bed, the second downstream temperature is the final temperature. Correspondingly, in the case of introduction into one or more further fluidized beds, such as a third downstream fluidized bed, fourth downstream fluidized bed, and fifth downstream fluidized bed, the final temperature is the temperature on removal from the last fluidized bed in respect of the cooling process.
It is possible to use one further fluidized bed, or two, or three, or four, or five, or six further fluidized beds, or more than six further fluidized beds.
In this way, a final temperature below the primary cooling temperature can be achieved without increasing the volume flow of the process gas through the primary fluidized bed. Owing to the higher temperature of the process exhaust gas discharged from the primary fluidized bed, this permits more efficient heat recovery from this process exhaust gas, and it permits easier handling of the particles owing to their temperature being below the primary cooling temperature.
According to an advantageous embodiment, the process gas which is fed to that fluidized bed which the particles enter directly after they are produced comprises process exhaust gas from at least one of the further fluidized beds. In this case, the Date Recue/Date Received 2022-11-03 process exhaust gas which is provided for feeding can also be cleaned and/or cooled before being fed in.
In this case, the process gas which is fed to that fluidized bed which the particles enter directly after they are produced already contains heat extracted from the particles in the further fluidized bed(s). Therefore, the process exhaust gas from this fluidized bed will have a higher temperature - when compared with the introduction of process gas which has not yet extracted any heat from the particles, i.e. has a so-called process gas base temperature. This allows more efficient heat recovery from this process exhaust gas. Based on the nomenclature introduced above, the process exhaust gas of that fluidized bed which the particles enter directly after they are produced - that is to say the primary fluidized bed - can be referred to as the primary exhaust gas. In corresponding fashion, the process exhaust gas from the first downstream fluidized bed can be referred to as the first downstream process exhaust gas; the situation is analogous for further downstream fluidized beds.
According to this embodiment, therefore, process gas which is fed to the primary fluidized bed comprises process exhaust gas from at least one of the further downstream fluidized beds. It may also consist of such a process exhaust gas.
In this way, a higher temperature of process exhaust gas intended for heat recovery and a lower final temperature of the granules can be achieved than with the sole use of primary process exhaust gas or the use of process exhaust gas from only one fluidized bed. This allows more efficient heat recovery.
According to an advantageous embodiment, after mixing, process exhaust gas from that fluidized bed which the particles enter directly after they are produced is discharged together with at Date Recue/Date Received 2022-11-03 least some of the process exhaust gas from at least one of the further fluidized beds. Discharge together with at least some of the process exhaust gas from all further fluidized beds is preferred; discharge together with all of the process exhaust gases from all further fluidized beds is particularly preferred.
In this way, a higher temperature of process exhaust gas intended for heat recovery and a lower final temperature of the granules can be achieved than with the sole use of primary process exhaust gas or the use of process exhaust gas from only one fluidized bed. This allows more efficient heat recovery.
The fluidized beds supplying these process exhaust gases which are discharged together are preferably fed with the same process gas; e.g. air at ambient temperature or cooled air, e.g. air at a temperature of 0 C.
As a result of the process management according to the invention, a fluidized bed with a large ratio of area to height can be handled effectively; operation of dry granulation of molten slag under unfavorable conditions is thereby facilitated or made possible, even under circumstances restricted by spatial conditions. In addition, the process management according to the invention enables increased efficiency of heat recovery from process exhaust gas.
The invention further relates to a granulator comprising, within a casing of the granulator, an atomizer unit for producing particles from molten material, a feed device for feeding molten material to the atomizer unit, at least one fluidized-bed space region with a gas feed for process gas, and at least one gas discharge line for process exhaust gas from the fluidized-bed space region, characterized in that the gas feed has a plurality of feed zones, at least for the fluidized-bed space region which is suitable for the entry of Date Recue/Date Received 2022-11-03 the particles directly after they are produced by means of an atomizer unit.
The granulator is a device for dry granulation of molten material.
The granulator is bounded by a casing.
The atomizer unit is used to atomize the molten material. In this context, atomization means the generation of particles from the molten material.
A fluidized-bed space region is designed to form a fluidized bed of particles, formed by the atomizer unit from the molten material, with gas - this gas is process gas for the respective fluidized bed; the process gas for a fluidized bed may also be process exhaust gas from another fluidized bed.
The fluidized-bed space region is suitable for cooling the particles by means of process gas.
At least one fluidized-bed space region is present, or it is also possible for a plurality of fluidized-bed space regions to be present. At least one fluidized-bed space region, preferably only one fluidized-bed space region, is suitable for the entry of the particles directly after they are produced by means of an atomizer unit. The gas feed has a plurality of feed zones, at least for that fluidized-bed space region which is suitable for the entry of the particles directly after they are produced by means of an atomizer unit; the feed zones are separated from one another. They are used to feed process gas into the fluidized-bed space region in a plurality of separate zones.
The granulator comprises a device for open-loop and/or closed-loop control of the volume flow of the process gas. The Date Recue/Date Received 2022-11-03 granulator preferably comprises a device for mutually independent open-loop and/or closed-loop control of the volume flow and/or the pressure of the process gas in at least two zones; this means two zones which feed process gas into the same fluidized-bed space region.
The granulator preferably comprises a device for determining the height of a fluidized bed, which is formed in the fluidized-bed space region during operation, over at least two feed zones.
This device comprises a pressure gage, for example.
The granulator preferably comprises a device for determining the temperature of a fluidized bed, which is formed in the fluidized-bed space region during operation, over at least two feed zones.
This device comprises a thermocouple and/or a resistance thermometer, for example.
The granulator preferably comprises a device for determining the intensity of a fluidized bed, which is formed in the fluidized-bed space region during operation, over at least one feed zone.
This device comprises a pressure gage, for example.
The devices discussed for determining the height, the temperature and the intensity of the fluidized bed are preferably suitable for transmitting data to the devices mentioned for open-loop and/or closed-loop control.
The granulator preferably comprises a plurality of fluidized-bed space regions. It can comprise two, or three, or four, or five, or six, or seven fluidized-bed space regions, or more than seven fluidized-bed space regions. In respect of the feed or flow of the process gas, the further fluidized-bed space region or regions can be arranged in series or in parallel with that fluidized-bed space region which is suitable for the entry of particles directly after they are produced by means of an Date Recue/Date Received 2022-11-03 atomizer unit. A combination of in-series and parallel arrangement is also possible.
According to one variant, the gas feed for the fluidized-bed space region which is suitable for the entry of particles directly after they are produced by means of an atomizer unit has at least one outlet of a gas discharge line from at least one other fluidized-bed space region.
According to one variant, the gas discharge line of the fluidized-bed space region which is suitable for the entry of particles directly after they are produced by means of an atomizer unit has at least one outlet of a gas discharge line from at least one other fluidized-bed space region.
According to one variant, the gas feeds to these fluidized-bed space regions start from a single gas feed line, i.e. they originate from a common gas feed line. In principle, they can also start from different gas feed lines.
Of course, the granulator also comprises one or more removal devices for removing granules formed during operation from the fluidized-bed space regions.
The present application furthermore relates to a signal processing device having a machine-readable program code, characterized in that it has open-loop and/or closed-loop control commands for carrying out a method according to the invention. It furthermore relates to a signal processing device for carrying out a method according to the invention.
The present application furthermore relates to a machine-readable program code for a signal processing device, characterized in that the program code has open-loop and/or closed-loop control commands which cause the signal processing Date Recue/Date Received 2022-11-03 device to carry out a method according to the invention. It furthermore relates to a computer program product comprising commands for a signal processing device which, when the program for the signal processing device is executed, cause the signal processing device to carry out a method according to the invention.
The present application furthermore relates to a storage medium having a machine-readable program code according to the invention stored thereon. It furthermore relates to a storage medium containing a computer program stored thereon for carrying out a method according to the invention.
The present application furthermore relates to a computer program product which comprises a program and can be loaded directly into a memory of a granulator, having program means for closed-loop and/or open-loop control of the granulator in accordance with a method according to the invention when the program is executed by the closed-loop control device and/or open-loop control device.
Brief description of the drawings The invention is now explained in greater detail by means of exemplary embodiments. The drawings are by way of example and are intended to illustrate the idea of the invention but in no way to restrict it or even to represent it definitively. In the drawings:
Figure 1shows a schematic side view of a section through a granulator according to the invention.
Figure 2shows a schematic view referring to figure 1 from above with illustration of devices for open-loop and/or closed-loop control.
Date Recue/Date Received 2022-11-03 Figure 3shows a block flow diagram of an in-series fluidized bed arrangement.
Figure 4shows a block flow diagram for a parallel fluidized bed arrangement.
Description of the embodiments Examples Figure 1 shows schematically a side view of a section through a granulator 1 according to the invention. The granulator 1 has a casing 2; in the variant shown, the regions of the casing on which particles impinge are water-cooled. An atomizer unit 3, e.g. a rotary atomizer, is arranged in the granulator 1. A feed device 4 for feeding molten material to the atomizer unit 3 is used to feed in molten material, for example blast furnace slag.
A flow of particles produced by means of the atomizer unit 3 and impinging on the casing, as well as particles falling from the casing, are shown by dashed lines. The falling particles fall into a fluidized bed 5 - illustrated by dots - which in the variant shown extends symmetrically around the atomizer unit 3.
In the illustrated operating state, the fluidized bed 5 is formed in a fluidized-bed space region 6 of the granulator 1. The figure illustrates the fluidized bed 5 which the particles enter directly after they are produced. Process gas, in the case illustrated process air at ambient temperature, is fed to the fluidized-bed space region 6 or fluidized bed 5 by means of a gas feed 7. The gas feed has a plurality of feed zones 7a, 7b;
the process gas - illustrated by block arrows - is thus fed into the fluidized bed 5 in a plurality of separate zones. Process exhaust gas from the fluidized-bed space region 6 is discharged from the granulator 1 via the gas discharge line 8. Granule delivery 9a and 9b takes place at a plurality of points under the fluidized bed, counter to the flow of process gas.
Date Recue/Date Received 2022-11-03 Figure 2 shows schematically a view from above of a granulator 1 as in figure 1. It shows four separate zones 10a, 10b, 10c, 10d, in which process gas is fed into the fluidized bed (not illustrated) in four feed zones, and a device for open-loop and/or closed-loop control 11 of the volume flow F of the process gas; in the example shown, open-loop and/or closed-loop control in all zones takes place independently of other zones.
Devices for determining the height of the fluidized bed over the zones 10a, 10b, 10c, 10d are present and are embodied as pressure gages P; the pressure gages also serve as components of devices for determining the intensity over the zones 10a, 10b, 10c, 10d - if appropriate, determination is carried out in cooperation with the device for open-loop and/or closed-loop control 11.
Devices for determining the temperature of the fluidized bed over the zones 10a, 10b, 10c, 10d are present and are embodied as thermocouples T and/or resistance thermometers.
Process gas fed in is indicated by a block arrow.
Figure 3 shows schematically an arrangement with a plurality of fluidized-bed space regions 12a, 12b, 12c arranged in series with respect to process gas flow. Cooling to a particle primary cooling temperature Tpp is first carried out in fluidized-bed space region 12a in that fluidized bed which is entered by the particles - the particle flow is illustrated by straight arrows - directly after they are produced, that is to say the primary fluidized bed. Subsequently, cooling to the intermediate temperature Tpx and finally to the final particle temperature TpE
is carried out in the further fluidized beds or downstream fluidized beds in fluidized-bed space regions 12b, 12c. Process exhaust gas from the primary fluidized bed - the process gas flow is represented by zigzag arrows - has the temperature TGp.
Process exhaust gas from the downstream fluidized bed in fluidized-bed space region 12b has the intermediate temperature Date Recue/Date Received 2022-11-03 TGx. Process gas from the downstream fluidized bed in fluidized-bed space region 12c has the temperature TGE.
Particles or granules from the downstream fluidized bed in fluidized-bed space region 12c have the temperature TpE.
Particles or granules from the primary fluidized bed in fluidized-bed space region 12a have the temperature Tpp.
Particles or granules from the downstream fluidized bed in fluidized-bed space region 12b have the intermediate temperature TPX .
The process exhaust gas from fluidized-bed space region 12c is process gas from fluidized-bed space region 12b. The process exhaust gas from fluidized-bed space region 12b is process gas from fluidized-bed space region 12a. Since the respective gas feed lines are at the same time the gas discharge lines of some other fluidized-bed space region, they have an outlet of a gas discharge line from another fluidized-bed space region.
Figure 4 shows schematically an arrangement with a plurality of fluidized-bed space regions 13a, 13b, 13c arranged in parallel with respect to process gas flow. Process exhaust gas from that fluidized bed which the particles enter directly after they are produced - that is to say the primary fluidized bed - in fluidized-bed space region 13a is, after mixing, discharged together with at least some of the process exhaust gas from the two further fluidized beds - or downstream fluidized beds - in fluidized-bed space regions 13b and 13c. The same process gas is fed to the primary fluidized bed and the downstream fluidized beds via the gas feed line 14, which branches accordingly. The flow of particles into the primary fluidized bed, from the primary fluidized bed into the downstream fluidized bed in fluidized-bed space region 13b, from there into the downstream fluidized bed in fluidized-bed space region 13c, and from the downstream fluidized bed in fluidized-bed space region 13c is Date Recue/Date Received 2022-11-03 illustrated by thick arrows. In the primary fluidized bed, the particles are cooled to the primary temperature Tpp, and in the downstream fluidized bed, in fluidized-bed space region 13c, to the final temperature TPE. Exhaust gas 15 from the downstream fluidized bed in fluidized-bed space region 13c has the final temperature 'GE, exhaust gas 16 from the primary fluidized bed has the primary temperature TGp. These two exhaust gases are discharged from the granulator together with the exhaust gas from fluidized-bed space region 13b - at a temperature TGX from the cooling of the particles to the temperature TpX - achieve a mixing temperature TGpE, and the respective gas discharge lines open into one another.
Date Recue/Date Received 2022-11-03 List of reference signs 1 granulator
Prior art Dry granulation of molten material is a technology under development for processing molten material into solid granules.
Molten material is, for example, molten metal or metallurgical slag, for example molten blast furnace slag - the method is then also called dry slag granulation DSG and is described, for example, in EP2747920B1. In this context, dry means that the molten material does not come into direct contact with liquid water during granulation - this is, for example, a contrast to methods which are conventionally used in industry for granulating blast furnace slag, in which the molten slag is introduced into a stream of water. The granulator is a vessel which is bounded by a casing and which has a slag feed, a gas feed for the process gas and an exhaust line for heated process gas - also referred to as process exhaust gas in the context of this application - for example air - also referred to as process air. The molten material, for example liquid slag, is applied to an atomization unit located in the casing of the granulator;
this is, for example, a rapidly rotating unit, known as a rotary atomizer; something like this is shown, for example, in EP2747920B1. As a result of the forces which occur, the molten material is torn into fine droplets and thrown outward. These fine, initially still molten droplets are cooled in the Date Recue/Date Received 2022-11-03 granulator and solidify, this being accomplished, for example, by the process gas and by impingement on granulator surfaces -which may be cooled - for example the water-cooled casing of the granulator, as a result of which solid particles, referred to here as granules, are formed, which are then removed from the granulator. According to a known procedure, liquid or partially solidified - that is to say partially liquid and partially solidified - droplets fall downward in the granulator, after leaving the rotary atomizer and subsequently striking the casing of the granulator, into a fluidized bed. In the fluidized bed, the particles are continuously solidified. There is a flow of process gas counter to gravity through the fluidized bed. The particles are thereby placed in a fluidized state, and the quantity through which the gas flows takes on virtually fluid-like properties, this also being referred to as fluidizing and being a known principle in process engineering. Starting from a state known as a fixed bed, in which the process gas flows through a bulk material without fluidizing it, fluidization begins at a defined point as the process gas velocity increases.
The type of fluidization present in a fluidized bed depends essentially on the gas velocity, gas density, and also on the particle bulk density, the shape, and the particle size distribution of the particles. The term fluidized bed is equivalent to the term fluid bed; the two terms are used as synonyms in the present application. The transition from a fixed bed to a fluidized bed takes place at the fluidization point.
The granulator comprises devices for introducing process gas, which is intended to form a fluidized bed of particles.
Such fluidized-bed cooling is advantageous because it is possible in a fluidized bed, owing to the high convection and the volume/surface area ratios of the particles, for a large amount of heat to be rapidly dissipated into the process gas and carried away by the flow of process gas. In addition, the movement of a fluidized bed ensures that freshly arriving Date Recue/Date Received 2022-11-03 particles - which are still particularly hot and may thus be at least partially soft and sticky and therefore tend to agglomerate - do not remain at the surface of the fluidized bed but are moved to other points or mixed into the interior of the fluidized bed. As a result, the probability of several droplets which arrive successively at the surface of the fluidized bed, or still hot, not fully solidified - and therefore sticky -particles coming into contact with one another and agglomerating is almost completely eliminated. Agglomeration of the particles would promote growth into larger, heavier particles, which would seriously impair the process.
Dry granulation with fluidized-bed cooling offers the possibility of recovering the heat transferred to the process gas during the cooling of the particles from the process gas.
Conventional granulation technologies based on fluidized-bed cooling for dry granulation of molten material, such as, for example, liquid blast furnace slag, with rotary atomizers and exploitation of impingement on the casing have a large diameter since, in order to avoid agglomeration of liquid and/or partially solidified droplets and/or fully solidified particles during flight from the rotary atomizer to the casing or after impingement on the casing, the selected clearance of the casing - which is generally arranged in a rotationally symmetrical manner with respect to the rotary atomizer and is therefore as a rule round in cross section - has to be sufficiently large. A
relatively large clearance leads to fanning out of the flow of droplets or particles coming from the rotary atomizer, with the result that the droplets or particles fly less close to one another or are less close to striking one another. This reduces the risk of agglomeration during flight or upon impact.
Agglomeration can occur on impact, for example, if completely or partially liquid particles are deformed on impact and, as a result, come into contact with adjacently impinging particles.
Date Recue/Date Received 2022-11-03 Since the particles fall downward after impinging on the casing, following the force of gravity, the size of the impingement region also affects the area of the fluidized bed, which must be present at least underneath the impingement region.
Furthermore, the area required for a desired cooling potential is also affected by the temperature, mass flow and thus heat input of the particles into the fluidized bed, and what gas velocity ranges are necessary for the size distribution of particles in order to maintain a fluidized bed. Given a limited maximum velocity of the gas flow, it will be necessary to enlarge the area of the fluidized bed for the purpose of increasing the quantity of gas which can be introduced into the fluidized bed at the maximum gas velocity in order, for example, to achieve a desired increased cooling effect.
The height of a fluidized bed is limited by the resulting pressure loss of the gas flowing up through it from below. This pressure loss, caused by the production of the fluidized bed state during flow-through, determines what pressure must be provided during introduction in order to maintain the gas flow necessary for the desired cooling effect. The higher the pressure to be applied, the higher the energy consumption for the introduction of the gas. The higher the fluidized bed, the greater the pressure loss. Structural conditions can also limit the achievable height of the fluidized bed.
Consequently, in conventional granulation technologies, based on fluidized-bed cooling, for dry granulation of molten material - such as, for example, blast furnace slag - with rotary atomizers, the ratio of area to height is relatively large in comparison with other methods which utilize fluidized beds for heat exchange and/or mass transfer, such as, for example, FINEM
fluidized-bed reduction.
Date Recue/Date Received 2022-11-03 However, with a large area and, at the same time, a small height of the fluidized bed, problems arise with such a dry granulation method. For example, local collapse of the fluidized bed can occur as a result of inhomogeneities in the granulation process, which, for example with respect to the cross section of the fluidized bed, cause non-rotationally symmetrical distribution of the particles falling from the casing; formation of hot spots as a result of poor horizontal mixing due to weak turbulence in this respect in the fluidized bed; and nonuniform fluidization, especially when starting up the fluidized bed. Such problems can greatly promote agglomeration because there may be local accumulation of droplets or hot, sticky particles that are not rapidly cooled to complete solidification. Excessively large agglomerates can impair the maintenance of the fluidized bed and require a halt in operations for their removal. In order to avoid problems due to nonuniform fluidization, the supply of process gas - or the supply of air when air is used as the fluidizing or cooling gas - to the fluidized bed has hitherto been provided with a pressure which allows the fluidized bed to be formed to a sufficiently great extent even in poorly fluidized regions. It is disadvantageous here that well fluidized regions are supplied with a pressure above the pressure required for them - this leads to higher energy consumption for the pressure-generating units and reduces the latitude for varying the gas flow through the fluidized bed. It also increases the quantity of process gas passed through these regions, and this is unfavorable for heat recovery from the process gas owing to a lower temperature.
Summary of the invention Technical problem Date Recue/Date Received 2022-11-03 One problem addressed by the present invention is therefore that of presenting apparatus and methods which at least partially reduce or solve such problems.
Technical solution This problem is solved by a method for dry granulation of molten material, wherein particles produced from this material are cooled in at least one fluidized bed by means of process gas, characterized in that, at least in that fluidized bed which the particles enter directly after they are produced, the process gas is fed into the fluidized bed in a plurality of separate zones.
The molten material originates from one or more mineralogical processes - such as the production of a rock melt in a cupola furnace for the production of mineral wool, also called rock wool - and/or from one - or more - metallurgical processes. The molten material is preferably molten metallurgical slag - i.e.
slag from a metallurgical process. It can also comprise mixtures of different types of slag.
These are, for example, slags resulting from reduction processes on ferrous materials for the production of iron, such as, for example, slags during the operation of blast furnaces or smelting reduction processes, such as, for example, COREM or FINEM; or they are slags produced during the melting of solid products - for example direct reduced iron (DRI) - from direct reduction processes - which can, for example, involve melting down DRI in a vessel - which is not, for example, an LD
steelworks converter for the production of crude steel - with resistance heating by electric current and/or by an electric arc, or melting down DRI in a steelworks converter, for example an LD steelworks converter.
Date Recue/Date Received 2022-11-03 These are, for example, slags produced in steelworks processes for the production of steel from iron, for example slag from the operation of LD (BOF), AOD, EAF. It is preferably slag from the production of pig-iron-like melt or of pig-iron melt - for example by means of smelting reduction processes, such as, for example, COREXC) or FINEXC) or blast-furnace processes -particularly preferably blast furnace slag. Another preferred option is slag from a DRI melting down process.
In the course of dry granulation, particles are produced from the molten material. The production of particles from the molten material is accomplished by means of an atomizer unit, preferably by means of a rotary atomizer. In this context, atomization means the generation of particles from the molten material. A rotary atomizer is based on the principle of applying liquid material to a rotating body, the rotation is transferred from the rotating body to the liquid, and droplets are released from the liquid as a result of centrifugal force, i.e. the liquid is atomized.
Here, the term particles includes liquid droplets, partially solidified particles - that is to say particles which are partially liquid and partially solid; for example particles which are solid on the outside and liquid on the inside - and fully solidified particles. Liquid, partially solidified and fully solidified particles may be sticky. Here, stickiness refers to the ability to adhere to or agglomerate with other particles produced during dry granulation.
The particles are formed from molten material. Molten material has a temperature above its melting point, and the particles accordingly contain more thermal energy than in the solid state.
Cooling is intended to solidify the particles to such an extent that there is no longer any tendency for agglomeration, due to Date Recue/Date Received 2022-11-03 stickiness, of significance for the operation of the fluidized bed.
In this context, dry granulation means that the molten material does not come into direct contact with liquid water during granulation. However, liquid water can contribute indirectly to cooling, for example if the casing of the granulator is water-cooled.
The particles produced during dry granulation are cooled by means of process gas in at least one fluidized bed.
They can therefore be cooled in one fluidized bed or in a plurality of fluidized beds; in the case of a plurality of fluidized beds, the particles pass through these in succession.
Feeding of the process gas into the fluidized bed in a plurality of separate zones can take place in one, some or all of these fluidized beds.
Since a fluidized bed is to be formed for intensive heat exchange, cooling is performed by means of gas, also referred to here as process gas. Air is preferably used as the process gas since it is readily available, and is here also referred to as process air. The fluidized bed is, for example, a turbulent fluidized bed or a slugging fluidized bed.
According to the invention, the process gas of at least that fluidized bed which the particles enter directly after they are produced is fed into the fluidized bed in a plurality of separate zones. By this is meant the first fluidized bed into which the particles enter after their formation; the phrase "directly after their formation" includes other processes taking place after formation, before the particles enter a fluidized bed for the first time - for example striking the casing before they fall down from the casing into the fluidized bed.
Date Recue/Date Received 2022-11-03 In contrast to a hitherto customary single feed, i.e. feed in a single zone, for example a distributor plate at the bottom of the vessel surrounding the fluidized bed, through which gas is fed in from a single feed - and thus at a single pressure -feeding does not take place in a single zone but in a plurality of zones. The separate zones adjoin one another and together cover the entire area of the fluidized bed. In the case of conventional feeding in a single zone, the area of the fluidized bed is covered by this single zone.
According to the invention, feeding is carried out in at least two zones, preferably in at least three zones, particularly preferably at least four zones. Gas can be fed in, for example, in two zones or in three zones or in four zones or in five zones or in six zones or in seven zones or in eight zones or in nine zones or in ten zones or in more than ten zones.
Advantageous effects of the invention The feeding, according to the invention, of the process gas into the fluidized bed in a plurality of separate zones makes it possible to set different conditions zone by zone, e.g. by open-loop and/or closed-loop control. For example, different pressures can be selected for the supplied process gas in different zones. For example, the volume flow - that is, the volume of process gas fed to the fluidized bed per unit of time - selected in different zones can be different. For example, the pressure and/or volume flow can be varied zone by zone, optionally independently of other zones. In contrast to conventional feeding in a single zone, it is thus possible to supply each zone in an optimum manner with process gas with respect to its requirements, for example in respect of pressure and/or volume flow - for example in an energy-optimal manner.
Differences between different regions of the fluidized bed with respect to fluidization can be automatically compensated for or Date Recue/Date Received 2022-11-03 brought about by corresponding zone-by-zone changes by the control system or by manual changing of the parameters by the operating personnel.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to compensate for differences in the bed height of the fluidized bed between different regions; such differences can occur, for example, as a result of asymmetrically distributed impingement on the casing and correspondingly asymmetrically distributed falling into the fluidized bed.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to compensate for differences in the temperature in the fluidized bed between different regions; such differences can occur, for example, as a result of asymmetrically distributed impingement on the casing and correspondingly asymmetrically distributed falling into the fluidized bed.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to compensate for differences in the extent of fluidization in the fluidized bed between different regions.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure and/or volume flow in order to bring agglomerates which have been deposited at the bottom of the fluidized bed in only one region into the fluidized state.
For example, it may be desirable to bring about, for example temporarily, differences in respect of pressure in order to produce uniform process gas distribution in all regions of the fluidized bed; nonuniform air distribution can be brought about, Date Recue/Date Received 2022-11-03 for example, by blocking individual openings for feeding in process gas, and/or by different particle size distribution in the fluidized bed due to asymmetrically distributed impingement on the casing and correspondingly asymmetrically distributed falling into the fluidized bed in conjunction with poor horizontal mixing of the fluidized bed.
Zonal adjustability also offers the advantage that an increase in the quantity of process gas to eliminate irregularities is limited, this being advantageous for achieving the highest possible temperature of the process exhaust gas leaving the granulator. Heat recovery from this process exhaust gas is more efficient at higher temperatures. Thus, energy recovery from the process exhaust gas is possible in an efficient and economically viable manner even with the operation of fluidized beds that have a large area and large quantities of process gas as a result.
The process gas is fed into the fluidized bed in a plurality of separate zones, but the fluidized bed itself is not subdivided by devices, such as, for example, walls, into partial fluidized beds which together form the fluidized bed of the device for dry granulation - in this case, mixing would be inhibited, for example, and particles could stick. The fluidized bed is thus one in which process gas is fed in in a plurality of separate zones.
According to a preferred embodiment, in the method the volume flow and/or pressure of the process gas in at least two zones is/are subject to open-loop and/or closed-loop control independently of other zones.
Adaptation to local requirements in the fluidized bed is thereby made easier.
Date Recue/Date Received 2022-11-03 The pressure of the process gas means the pressure at which the process gas is supplied to the fluidized bed.
According to a preferred embodiment, in the method the height of the fluidized bed is determined over, preferably perpendicularly over, at least two zones.
This allows local differences to be detected; on this basis, countermeasures can be taken if necessary. Determination can take place directly - by height measurement - or indirectly -by calculation from measured variables of a different kind. The height of the fluidized bed in a region is determined, for example, on the basis of pressure measurement in the fluidized bed, for example at the bottom of the fluidized bed, in this region.
According to a preferred embodiment, in the method the temperature in the fluidized bed is determined over, preferably perpendicularly over, at least two zones. Determination can take place directly - by temperature measurement - or indirectly -by calculation from measured variables of a different kind. The temperature of the fluidized bed in a region is determined, for example, on the basis of measurements with a thermocouple or with a resistance thermometer. This provides information, for example, about the cooling requirement in this region of the fluidized bed or about the risk of agglomeration due to heat-induced viscosity or stickiness of the particles.
According to a preferred embodiment, in the method the intensity of the fluidized bed is determined over, preferably perpendicularly over, at least one of the zones. Determination can take place, for example, on the basis of measurements of the pressure in the fluidized bed, preferably in a locally fixed manner over the bottom of the fluidized bed, or evaluation of the time characteristic of the pressure development. This Date Recue/Date Received 2022-11-03 provides information, for example, about irregularities in the fluidized bed and the mixing, and the associated risk of formation of hot spots or of agglomerations or deviations from desired properties of the granules, such as, for example, bulk density and particle size distribution. The intensity of the fluidized bed is obtained from the time characteristic of the pressure in the fluidized bed or can be read out from it. There are various methods for determining the intensity. The following is a list of possibilities, although other methods of intensity evaluation are possible.
- Detection of the minimum (Min) and maximum (Max) pressure value occurring within a defined time period A. The difference between the maximum and the minimum is formed, and represents the intensity of the fluidized bed. The duration of the selected time period A is between 5 sec (seconds) and 5 min (minutes), preferably between 15 sec and 1 min.
- Detection of the minimum (Min) and maximum (Max) pressure value occurring within a defined time period B. The duration of the selected time period B is between 5 sec and min, preferably between 15 sec and 1 min. Determination of an average value of all recorded pressure measurements within a period of time C. The duration of the selected time period C is between 10 sec and 10 min, preferably between 1 min and 3 min. Time period B is in this case at the end of time period C, but fully within time period C.
Time period B is always shorter than or equal to time period C. The differences between the maximum and minimum pressure values and the average value are formed and give some insight into the intensity of the fluidized bed.
- Determination of a standard deviation - or similar methods of determining deviations - of the detected measured values for the pressure within a defined time period D. The duration of the selected time period D is between 5 sec and Date Recue/Date Received 2022-11-03 min, preferably between 15 sec and 1 min. The standard deviation represents the intensity.
The greater the value of the intensity, the greater the intensity of the fluidized bed. For example, if the pressure fluctuates sharply around an average value with respect to time within a defined time period, it is possible to refer to a high intensity and, if fluctuation is low, it is possible to refer to low intensity.
The features discussed, namely the height of the fluidized bed, the temperature in the fluidized bed, and the intensity of the fluidized bed, can be used for open-loop and/or closed-loop control of the method.
Closed-loop or open-loop control can be carried out, for example, in such a way that, at individual measuring points for determining height or temperature or intensity - or other parameters, deviations from average values or specifications for these parameters are detected as a result of monitoring. On this basis, for example, the volume flow of the process gas in a zone can be increased if the temperature in the fluidized bed over this zone is too high, or the volume flow can be reduced if the temperature is too low. The volume flow of the process gas in a zone can also be increased if the height of the fluidized bed over this zone is too great, in which case an excess of particles is transported away from the region by increased mixing, or the volume flow can be reduced if the height is too small. The volume flow of the process gas in a zone can also be increased if the intensity of the fluidized bed over this zone is too low, or the volume flow can be reduced if the intensity is too high.
The particles produced during dry granulation are cooled by means of process gas in at least one fluidized bed. They can therefore be cooled in one fluidized bed or in a plurality of Date Recue/Date Received 2022-11-03 fluidized beds; in the case of a plurality of fluidized beds, the particles pass through these in succession.
According to an advantageous embodiment of the method according to the invention, cooling is carried out in stages to a final temperature, first to a primary cooling temperature in that fluidized bed which the particles enter directly after they are produced, and then to the final temperature in at least one further fluidized bed.
According to one of many possible embodiments, at least in one of the further fluidized beds, process gas is fed in in a plurality of separate zones - that is to say, analogously to the feed into that fluidized bed which the particles enter directly after they are produced.
In respect of the feed or flow of the process gas, the further fluidized bed or beds can be arranged in series or in parallel with that fluidized bed which the particles enter directly after they are produced. A combination of in-series and parallel arrangement is also possible.
The fluidized bed which the particles enter directly after they are produced is also referred to here as the primary fluidized bed. When removed from this fluidized bed, the particles have what is referred to as the primary cooling temperature.
In one or more further fluidized beds, the particles are further cooled to a final temperature on removal from the last fluidized bed.
The particles are removed from the primary fluidized bed and introduced into a further fluidized bed - called the first downstream fluidized bed. The temperature of the particles on removal from the downstream fluidized bed is the first Date Recue/Date Received 2022-11-03 downstream temperature. If, after removal from the first downstream fluidized bed, the mixture is not introduced into a further fluidized bed, the first downstream temperature is the final temperature. If, after removal from the downstream fluidized bed, the mixture is introduced into a further fluidized bed - called the second downstream fluidized bed - the particles, after cooling in the second downstream fluidized bed, have the second downstream temperature when removed from the second downstream fluidized bed. If, after removal from the second downstream fluidized bed, the mixture is not introduced into a further fluidized bed, the second downstream temperature is the final temperature. Correspondingly, in the case of introduction into one or more further fluidized beds, such as a third downstream fluidized bed, fourth downstream fluidized bed, and fifth downstream fluidized bed, the final temperature is the temperature on removal from the last fluidized bed in respect of the cooling process.
It is possible to use one further fluidized bed, or two, or three, or four, or five, or six further fluidized beds, or more than six further fluidized beds.
In this way, a final temperature below the primary cooling temperature can be achieved without increasing the volume flow of the process gas through the primary fluidized bed. Owing to the higher temperature of the process exhaust gas discharged from the primary fluidized bed, this permits more efficient heat recovery from this process exhaust gas, and it permits easier handling of the particles owing to their temperature being below the primary cooling temperature.
According to an advantageous embodiment, the process gas which is fed to that fluidized bed which the particles enter directly after they are produced comprises process exhaust gas from at least one of the further fluidized beds. In this case, the Date Recue/Date Received 2022-11-03 process exhaust gas which is provided for feeding can also be cleaned and/or cooled before being fed in.
In this case, the process gas which is fed to that fluidized bed which the particles enter directly after they are produced already contains heat extracted from the particles in the further fluidized bed(s). Therefore, the process exhaust gas from this fluidized bed will have a higher temperature - when compared with the introduction of process gas which has not yet extracted any heat from the particles, i.e. has a so-called process gas base temperature. This allows more efficient heat recovery from this process exhaust gas. Based on the nomenclature introduced above, the process exhaust gas of that fluidized bed which the particles enter directly after they are produced - that is to say the primary fluidized bed - can be referred to as the primary exhaust gas. In corresponding fashion, the process exhaust gas from the first downstream fluidized bed can be referred to as the first downstream process exhaust gas; the situation is analogous for further downstream fluidized beds.
According to this embodiment, therefore, process gas which is fed to the primary fluidized bed comprises process exhaust gas from at least one of the further downstream fluidized beds. It may also consist of such a process exhaust gas.
In this way, a higher temperature of process exhaust gas intended for heat recovery and a lower final temperature of the granules can be achieved than with the sole use of primary process exhaust gas or the use of process exhaust gas from only one fluidized bed. This allows more efficient heat recovery.
According to an advantageous embodiment, after mixing, process exhaust gas from that fluidized bed which the particles enter directly after they are produced is discharged together with at Date Recue/Date Received 2022-11-03 least some of the process exhaust gas from at least one of the further fluidized beds. Discharge together with at least some of the process exhaust gas from all further fluidized beds is preferred; discharge together with all of the process exhaust gases from all further fluidized beds is particularly preferred.
In this way, a higher temperature of process exhaust gas intended for heat recovery and a lower final temperature of the granules can be achieved than with the sole use of primary process exhaust gas or the use of process exhaust gas from only one fluidized bed. This allows more efficient heat recovery.
The fluidized beds supplying these process exhaust gases which are discharged together are preferably fed with the same process gas; e.g. air at ambient temperature or cooled air, e.g. air at a temperature of 0 C.
As a result of the process management according to the invention, a fluidized bed with a large ratio of area to height can be handled effectively; operation of dry granulation of molten slag under unfavorable conditions is thereby facilitated or made possible, even under circumstances restricted by spatial conditions. In addition, the process management according to the invention enables increased efficiency of heat recovery from process exhaust gas.
The invention further relates to a granulator comprising, within a casing of the granulator, an atomizer unit for producing particles from molten material, a feed device for feeding molten material to the atomizer unit, at least one fluidized-bed space region with a gas feed for process gas, and at least one gas discharge line for process exhaust gas from the fluidized-bed space region, characterized in that the gas feed has a plurality of feed zones, at least for the fluidized-bed space region which is suitable for the entry of Date Recue/Date Received 2022-11-03 the particles directly after they are produced by means of an atomizer unit.
The granulator is a device for dry granulation of molten material.
The granulator is bounded by a casing.
The atomizer unit is used to atomize the molten material. In this context, atomization means the generation of particles from the molten material.
A fluidized-bed space region is designed to form a fluidized bed of particles, formed by the atomizer unit from the molten material, with gas - this gas is process gas for the respective fluidized bed; the process gas for a fluidized bed may also be process exhaust gas from another fluidized bed.
The fluidized-bed space region is suitable for cooling the particles by means of process gas.
At least one fluidized-bed space region is present, or it is also possible for a plurality of fluidized-bed space regions to be present. At least one fluidized-bed space region, preferably only one fluidized-bed space region, is suitable for the entry of the particles directly after they are produced by means of an atomizer unit. The gas feed has a plurality of feed zones, at least for that fluidized-bed space region which is suitable for the entry of the particles directly after they are produced by means of an atomizer unit; the feed zones are separated from one another. They are used to feed process gas into the fluidized-bed space region in a plurality of separate zones.
The granulator comprises a device for open-loop and/or closed-loop control of the volume flow of the process gas. The Date Recue/Date Received 2022-11-03 granulator preferably comprises a device for mutually independent open-loop and/or closed-loop control of the volume flow and/or the pressure of the process gas in at least two zones; this means two zones which feed process gas into the same fluidized-bed space region.
The granulator preferably comprises a device for determining the height of a fluidized bed, which is formed in the fluidized-bed space region during operation, over at least two feed zones.
This device comprises a pressure gage, for example.
The granulator preferably comprises a device for determining the temperature of a fluidized bed, which is formed in the fluidized-bed space region during operation, over at least two feed zones.
This device comprises a thermocouple and/or a resistance thermometer, for example.
The granulator preferably comprises a device for determining the intensity of a fluidized bed, which is formed in the fluidized-bed space region during operation, over at least one feed zone.
This device comprises a pressure gage, for example.
The devices discussed for determining the height, the temperature and the intensity of the fluidized bed are preferably suitable for transmitting data to the devices mentioned for open-loop and/or closed-loop control.
The granulator preferably comprises a plurality of fluidized-bed space regions. It can comprise two, or three, or four, or five, or six, or seven fluidized-bed space regions, or more than seven fluidized-bed space regions. In respect of the feed or flow of the process gas, the further fluidized-bed space region or regions can be arranged in series or in parallel with that fluidized-bed space region which is suitable for the entry of particles directly after they are produced by means of an Date Recue/Date Received 2022-11-03 atomizer unit. A combination of in-series and parallel arrangement is also possible.
According to one variant, the gas feed for the fluidized-bed space region which is suitable for the entry of particles directly after they are produced by means of an atomizer unit has at least one outlet of a gas discharge line from at least one other fluidized-bed space region.
According to one variant, the gas discharge line of the fluidized-bed space region which is suitable for the entry of particles directly after they are produced by means of an atomizer unit has at least one outlet of a gas discharge line from at least one other fluidized-bed space region.
According to one variant, the gas feeds to these fluidized-bed space regions start from a single gas feed line, i.e. they originate from a common gas feed line. In principle, they can also start from different gas feed lines.
Of course, the granulator also comprises one or more removal devices for removing granules formed during operation from the fluidized-bed space regions.
The present application furthermore relates to a signal processing device having a machine-readable program code, characterized in that it has open-loop and/or closed-loop control commands for carrying out a method according to the invention. It furthermore relates to a signal processing device for carrying out a method according to the invention.
The present application furthermore relates to a machine-readable program code for a signal processing device, characterized in that the program code has open-loop and/or closed-loop control commands which cause the signal processing Date Recue/Date Received 2022-11-03 device to carry out a method according to the invention. It furthermore relates to a computer program product comprising commands for a signal processing device which, when the program for the signal processing device is executed, cause the signal processing device to carry out a method according to the invention.
The present application furthermore relates to a storage medium having a machine-readable program code according to the invention stored thereon. It furthermore relates to a storage medium containing a computer program stored thereon for carrying out a method according to the invention.
The present application furthermore relates to a computer program product which comprises a program and can be loaded directly into a memory of a granulator, having program means for closed-loop and/or open-loop control of the granulator in accordance with a method according to the invention when the program is executed by the closed-loop control device and/or open-loop control device.
Brief description of the drawings The invention is now explained in greater detail by means of exemplary embodiments. The drawings are by way of example and are intended to illustrate the idea of the invention but in no way to restrict it or even to represent it definitively. In the drawings:
Figure 1shows a schematic side view of a section through a granulator according to the invention.
Figure 2shows a schematic view referring to figure 1 from above with illustration of devices for open-loop and/or closed-loop control.
Date Recue/Date Received 2022-11-03 Figure 3shows a block flow diagram of an in-series fluidized bed arrangement.
Figure 4shows a block flow diagram for a parallel fluidized bed arrangement.
Description of the embodiments Examples Figure 1 shows schematically a side view of a section through a granulator 1 according to the invention. The granulator 1 has a casing 2; in the variant shown, the regions of the casing on which particles impinge are water-cooled. An atomizer unit 3, e.g. a rotary atomizer, is arranged in the granulator 1. A feed device 4 for feeding molten material to the atomizer unit 3 is used to feed in molten material, for example blast furnace slag.
A flow of particles produced by means of the atomizer unit 3 and impinging on the casing, as well as particles falling from the casing, are shown by dashed lines. The falling particles fall into a fluidized bed 5 - illustrated by dots - which in the variant shown extends symmetrically around the atomizer unit 3.
In the illustrated operating state, the fluidized bed 5 is formed in a fluidized-bed space region 6 of the granulator 1. The figure illustrates the fluidized bed 5 which the particles enter directly after they are produced. Process gas, in the case illustrated process air at ambient temperature, is fed to the fluidized-bed space region 6 or fluidized bed 5 by means of a gas feed 7. The gas feed has a plurality of feed zones 7a, 7b;
the process gas - illustrated by block arrows - is thus fed into the fluidized bed 5 in a plurality of separate zones. Process exhaust gas from the fluidized-bed space region 6 is discharged from the granulator 1 via the gas discharge line 8. Granule delivery 9a and 9b takes place at a plurality of points under the fluidized bed, counter to the flow of process gas.
Date Recue/Date Received 2022-11-03 Figure 2 shows schematically a view from above of a granulator 1 as in figure 1. It shows four separate zones 10a, 10b, 10c, 10d, in which process gas is fed into the fluidized bed (not illustrated) in four feed zones, and a device for open-loop and/or closed-loop control 11 of the volume flow F of the process gas; in the example shown, open-loop and/or closed-loop control in all zones takes place independently of other zones.
Devices for determining the height of the fluidized bed over the zones 10a, 10b, 10c, 10d are present and are embodied as pressure gages P; the pressure gages also serve as components of devices for determining the intensity over the zones 10a, 10b, 10c, 10d - if appropriate, determination is carried out in cooperation with the device for open-loop and/or closed-loop control 11.
Devices for determining the temperature of the fluidized bed over the zones 10a, 10b, 10c, 10d are present and are embodied as thermocouples T and/or resistance thermometers.
Process gas fed in is indicated by a block arrow.
Figure 3 shows schematically an arrangement with a plurality of fluidized-bed space regions 12a, 12b, 12c arranged in series with respect to process gas flow. Cooling to a particle primary cooling temperature Tpp is first carried out in fluidized-bed space region 12a in that fluidized bed which is entered by the particles - the particle flow is illustrated by straight arrows - directly after they are produced, that is to say the primary fluidized bed. Subsequently, cooling to the intermediate temperature Tpx and finally to the final particle temperature TpE
is carried out in the further fluidized beds or downstream fluidized beds in fluidized-bed space regions 12b, 12c. Process exhaust gas from the primary fluidized bed - the process gas flow is represented by zigzag arrows - has the temperature TGp.
Process exhaust gas from the downstream fluidized bed in fluidized-bed space region 12b has the intermediate temperature Date Recue/Date Received 2022-11-03 TGx. Process gas from the downstream fluidized bed in fluidized-bed space region 12c has the temperature TGE.
Particles or granules from the downstream fluidized bed in fluidized-bed space region 12c have the temperature TpE.
Particles or granules from the primary fluidized bed in fluidized-bed space region 12a have the temperature Tpp.
Particles or granules from the downstream fluidized bed in fluidized-bed space region 12b have the intermediate temperature TPX .
The process exhaust gas from fluidized-bed space region 12c is process gas from fluidized-bed space region 12b. The process exhaust gas from fluidized-bed space region 12b is process gas from fluidized-bed space region 12a. Since the respective gas feed lines are at the same time the gas discharge lines of some other fluidized-bed space region, they have an outlet of a gas discharge line from another fluidized-bed space region.
Figure 4 shows schematically an arrangement with a plurality of fluidized-bed space regions 13a, 13b, 13c arranged in parallel with respect to process gas flow. Process exhaust gas from that fluidized bed which the particles enter directly after they are produced - that is to say the primary fluidized bed - in fluidized-bed space region 13a is, after mixing, discharged together with at least some of the process exhaust gas from the two further fluidized beds - or downstream fluidized beds - in fluidized-bed space regions 13b and 13c. The same process gas is fed to the primary fluidized bed and the downstream fluidized beds via the gas feed line 14, which branches accordingly. The flow of particles into the primary fluidized bed, from the primary fluidized bed into the downstream fluidized bed in fluidized-bed space region 13b, from there into the downstream fluidized bed in fluidized-bed space region 13c, and from the downstream fluidized bed in fluidized-bed space region 13c is Date Recue/Date Received 2022-11-03 illustrated by thick arrows. In the primary fluidized bed, the particles are cooled to the primary temperature Tpp, and in the downstream fluidized bed, in fluidized-bed space region 13c, to the final temperature TPE. Exhaust gas 15 from the downstream fluidized bed in fluidized-bed space region 13c has the final temperature 'GE, exhaust gas 16 from the primary fluidized bed has the primary temperature TGp. These two exhaust gases are discharged from the granulator together with the exhaust gas from fluidized-bed space region 13b - at a temperature TGX from the cooling of the particles to the temperature TpX - achieve a mixing temperature TGpE, and the respective gas discharge lines open into one another.
Date Recue/Date Received 2022-11-03 List of reference signs 1 granulator
2 casing
3 atomizer unit
4 feed device fluidized bed 6 fluidized-bed space region 7 gas feed 7a, 7b feed zones 8 gas discharge line 9a, 9b granule delivery 10a, 10b, 10c, 10d zones 11 device for open-loop and/or closed-loop control 12a, 12b, 12c fluidized-bed space regions 13a, 13b, 13c fluidized-bed space regions 14 gas feed line exhaust gas from the downstream fluidized bed 16 exhaust gas from the primary fluidized bed Date Recue/Date Received 2022-11-03
Claims (15)
1. A method for dry granulation of molten material, wherein particles produced from this material are cooled in at least one fluidized bed by means of process gas, characterized in that, at least in that fluidized bed which the particles enter directly after they are produced, the process gas is fed into the fluidized bed in a plurality of separate zones.'
2. The method as claimed in claim 1, characterized in that the volume flow and/or pressure of the process gas in at least two zones is/are subject to open-loop and/or closed-loop control independently of other zones.
3. The method as claimed in claim 1 or 2, characterized in that the height of the fluidized bed is determined over, preferably perpendicularly over, at least two zones.
4. The method as claimed in any of claims 1 to 3, characterized in that the temperature in the fluidized bed is determined over, preferably perpendicularly over, at least two zones.
5. The method as claimed in any of claims 1 to 4, characterized in that the intensity of the fluidized bed is determined over, preferably perpendicularly over, at least one of the zones.
6. The method as claimed in any of claims 1 to 5, characterized in that cooling is carried out in stages to a final temperature, first to a primary cooling temperature in that fluidized bed which the particles enter directly after they are produced, and then to the final temperature in at least one further fluidized bed.
7. The method as claimed in any of claims 1 to 6, characterized in that, after mixing, process exhaust gas from that fluidized bed which the particles enter directly after they are produced is discharged together with at least some of the process exhaust gas from at least one of the further fluidized beds.
8. A granulator comprising, within a casing of the granulator, an atomizer unit for producing particles from molten material, a feed device for feeding molten material to the atomizer unit, at least one fluidized-bed space region with a gas feed for process gas, and at least one gas discharge line for process exhaust gas from the fluidized-bed space region, characterized in that the gas feed has a plurality of feed zones, at least for the fluidized-bed space region which is suitable for the entry of the particles directly after they have been produced by means of an atomizer unit.
9. The granulator as claimed in claim 8, comprising a device for mutually independent open-loop and/or closed-loop control of the volume flow and/or the pressure of the process gas in at least two feed zones.
10. The granulator as claimed in claim 8 or 9, characterized in that the granulator comprises a device for determining the height of a fluidized bed, formed in the fluidized-bed space region during operation, over at least two feed zones.
11. The granulator as claimed in any of claims 8 to 10, characterized in that the granulator has a device for determining the temperature of a fluidized bed, formed in the fluidized-bed space region during operation, over at least two feed zones.
Date Recue/Date Received 2022-11-03
Date Recue/Date Received 2022-11-03
12. The granulator as claimed in any of claims 8 to 11, characterized in that the granulator comprises a device for determining the intensity of a fluidized bed, formed in the fluidized-bed space region during operation, over at least one feed zone.
13. The granulator as claimed in any of claims 8 to 12, characterized in that the granulator comprises a plurality of fluidized-bed space regions.
14. The granulator as claimed in any of claims 8 to 13, characterized in that the gas discharge line of the fluidized-bed space region which is suitable for the entry of particles directly after they are produced by means of an atomizer unit has at least one outlet of a gas discharge line from at least one other fluidized-bed space region.
15. A signal processing device having a machine-readable program code, characterized in that it has open-loop and/or closed-loop control commands for carrying out a method as claimed in any of claims 1 to 7.
Date Recue/Date Received 2022-11-03
Date Recue/Date Received 2022-11-03
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP20175483.5 | 2020-05-19 | ||
| EP20175483.5A EP3913070A1 (en) | 2020-05-19 | 2020-05-19 | Method and device for dry granulation |
| PCT/EP2021/063010 WO2021233836A1 (en) | 2020-05-19 | 2021-05-17 | Method and device for dry granulation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA3182146A1 true CA3182146A1 (en) | 2021-11-25 |
Family
ID=70779529
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA3182146A Pending CA3182146A1 (en) | 2020-05-19 | 2021-05-17 | Method and device for dry granulation |
Country Status (4)
| Country | Link |
|---|---|
| EP (2) | EP3913070A1 (en) |
| AU (1) | AU2021275362A1 (en) |
| CA (1) | CA3182146A1 (en) |
| WO (1) | WO2021233836A1 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19808439C1 (en) * | 1998-02-27 | 1999-09-30 | Degussa | Fluidized bed reactor and its use |
| WO2013029934A1 (en) | 2011-08-26 | 2013-03-07 | Siemens Vai Metals Technologies Ltd. | Slag granulation device |
| GB2528972B (en) * | 2014-08-08 | 2016-10-05 | Primetals Technologies Austria GmbH | Slag granulation system |
| WO2020094401A1 (en) * | 2018-11-05 | 2020-05-14 | Primetals Technologies Austria GmbH | Installation for dry granulation of slag and method for operating such an installation |
-
2020
- 2020-05-19 EP EP20175483.5A patent/EP3913070A1/en not_active Withdrawn
-
2021
- 2021-05-17 EP EP21725535.5A patent/EP4153788A1/en active Pending
- 2021-05-17 CA CA3182146A patent/CA3182146A1/en active Pending
- 2021-05-17 WO PCT/EP2021/063010 patent/WO2021233836A1/en unknown
- 2021-05-17 AU AU2021275362A patent/AU2021275362A1/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP3913070A1 (en) | 2021-11-24 |
| EP4153788A1 (en) | 2023-03-29 |
| AU2021275362A1 (en) | 2022-11-24 |
| WO2021233836A1 (en) | 2021-11-25 |
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