CN117062789A - Device and method for heat treatment of mineral raw materials - Google Patents
Device and method for heat treatment of mineral raw materials Download PDFInfo
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- CN117062789A CN117062789A CN202280024717.2A CN202280024717A CN117062789A CN 117062789 A CN117062789 A CN 117062789A CN 202280024717 A CN202280024717 A CN 202280024717A CN 117062789 A CN117062789 A CN 117062789A
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- calcination section
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- calcination
- raw material
- calciner
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- 239000002994 raw material Substances 0.000 title claims abstract description 74
- 238000010438 heat treatment Methods 0.000 title claims abstract description 21
- 229910052500 inorganic mineral Inorganic materials 0.000 title claims abstract description 11
- 239000011707 mineral Substances 0.000 title claims abstract description 11
- 238000000034 method Methods 0.000 title claims description 19
- 238000001354 calcination Methods 0.000 claims abstract description 172
- 239000000446 fuel Substances 0.000 claims description 49
- 239000007789 gas Substances 0.000 claims description 34
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 20
- 229910052757 nitrogen Inorganic materials 0.000 claims description 10
- 239000004449 solid propellant Substances 0.000 claims description 10
- 230000001133 acceleration Effects 0.000 claims description 2
- 239000000463 material Substances 0.000 description 14
- 238000002485 combustion reaction Methods 0.000 description 12
- 239000004568 cement Substances 0.000 description 10
- 238000009826 distribution Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000005265 energy consumption Methods 0.000 description 6
- 238000000265 homogenisation Methods 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000007787 solid Substances 0.000 description 5
- 239000002440 industrial waste Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 238000011144 upstream manufacturing Methods 0.000 description 3
- 239000002028 Biomass Substances 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 239000004927 clay Substances 0.000 description 2
- 239000002817 coal dust Substances 0.000 description 2
- 238000005262 decarbonization Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- 239000010791 domestic waste Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 239000010801 sewage sludge Substances 0.000 description 2
- 239000011343 solid material Substances 0.000 description 2
- 239000010920 waste tyre Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 235000012054 meals Nutrition 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002663 nebulization Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- JTJMJGYZQZDUJJ-UHFFFAOYSA-N phencyclidine Chemical class C1CCCCN1C1(C=2C=CC=CC=2)CCCCC1 JTJMJGYZQZDUJJ-UHFFFAOYSA-N 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Classifications
-
- 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
- B01J6/00—Heat treatments such as Calcining; Fusing ; Pyrolysis
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B7/00—Hydraulic cements
- C04B7/36—Manufacture of hydraulic cements in general
- C04B7/43—Heat treatment, e.g. precalcining, burning, melting; Cooling
- C04B7/434—Preheating with addition of fuel, e.g. calcining
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B7/00—Rotary-drum furnaces, i.e. horizontal or slightly inclined
- F27B7/20—Details, accessories, or equipment peculiar to rotary-drum furnaces
- F27B7/2016—Arrangements of preheating devices for the charge
- F27B7/2025—Arrangements of preheating devices for the charge consisting of a single string of cyclones
- F27B7/2033—Arrangements of preheating devices for the charge consisting of a single string of cyclones with means for precalcining the raw material
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Organic Chemistry (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Furnace Details (AREA)
Abstract
The invention relates to a device for heat treatment of mineral raw materials, wherein the device comprises a calciner (110), wherein the calciner (110) comprises at least a first calcination section (10) and a second calcination section (20), wherein the first calcination section (10) is arranged vertically, wherein the second calcination section (20) is arranged obliquely, wherein the second calcination section (20) has an angle alpha between a horizontal plane and a flow direction of the second calcination section (20), wherein the angle alpha is between 20 DEG and 80 DEG, wherein the first calcination section (10) has a first hydraulic diameter d h,1 Wherein the second calcination section (20) Having a second hydraulic diameter d h,2 Wherein the second hydraulic diameter d h,2 Less than or equal to the first hydraulic diameter d h,1 Multiplied by the sine of the angle alpha.
Description
Technical Field
The present invention relates to an apparatus and a method for heat treatment of mineral raw materials, in particular for the production of cement clinker.
Background
Facilities for clinker production include, for example, rotary kilns, calciners, and preheaters. When the material flow, which is initially a calcium-containing raw mixture and eventually solids of cement clinker, enters the rotary kiln via the calciner and then typically the cooler, the gas is counter-flowed from the rotary kiln to the calciner and thus to the preheater. While the material flow and the air flow of the clinker in the rotary kiln are counter-current, the air flow and the material flow in the calciner and the preheater, respectively, are concurrent and are subsequently separated in a cyclone. If the solid material is flowing down-stream, the gas stream must also be able to carry the material without the material falling off, settling or otherwise settling.
In the calciner, the combustion of the fuel generates energy on the one hand in the form of heat, which is consumed by the endothermic deacidification of the feedstock, i.e. with CO, on the other hand 2 Is arranged in the air. Because ofIt is useful here to introduce the fuel and the raw material close to each other into the calciner, so that regions with elevated temperatures are also avoided.
The fuel employed is typically an atomizable fuel such as coal dust. However, it is increasingly important to use alternative fuels or to increase the proportion thereof, e.g. to optimise the CO in the overall process 2 Balanced and also allows the use of low cost fuels. This also allows the cement industry to better integrate into the recycling economy. However, due to its size distribution, the alternative fuel is not always nebulizable, for example the energy required for comminution to achieve nebulization exceeds an economically viable level. In order to also allow the use of non-nebulizable alternative fuels, it is current practice to place a suitable combustion chamber on the side of the calciner. If the combustion chamber is arranged, for example, on the side of the calciner, where the raw material is not supplied, the location where energy is generated by combustion and the location where energy is consumed by deacidification are spatially separated.
DE 10 2018 206 673A1 discloses a method for producing cement clinker with an increased oxygen content.
DE 10 2018 206 674 A1 discloses another method for producing cement clinker with an increased oxygen content.
DE 37 35 A1 discloses a device for calcining powdery materials.
Disclosure of Invention
It is an object of the present invention to provide an apparatus and a method which allow direct combustion of very coarse-grained fuel to take place in a calciner.
This object is achieved by a device having the features indicated in claim 1 and by a method having the features indicated in claim 12. Advantageous developments are evident from the dependent claims, the following description and the figures.
The apparatus according to the invention is used for the heat treatment of mineral raw materials. Which is preferably an apparatus for producing cement clinker. However, the apparatus may also be used for heat treatment of clay or e.g. lithium ores. Hereinafter, cement clinker production is used as an example. The apparatus includes a calciner. The apparatus also typically includes a rotary kiln.The kiln is arranged downstream of the calciner with respect to the material flow (raw material to product) and upstream of the calciner with respect to the gas flow. However, the rotary kiln and the cooler directly connected to the calciner may also be omitted, for example, for other heat treatments. The apparatus also typically includes a preheater. The preheater is arranged upstream of the calciner with respect to the material flow (raw to product) and downstream of the calciner with respect to the gas flow. The preheater is for example composed of a plurality of downstream heat exchangers arranged in series with downstream cyclones. The calciner comprises at least a first calcination section and a second calcination section. The first calcination section is arranged vertically and the second calcination section is arranged obliquely. Tilting is understood to mean that the air flow through the second calcination section flows neither parallel to the earth's surface nor at an angle of 90 ° to the earth's surface. The second calcination section has an angle α between the horizontal plane and the flow direction of the second calcination section. The horizontal plane is parallel to the earth's surface. The angle alpha is between 20 deg. and 80 deg.. The first calcination section has a first hydraulic diameter d h,1 And the second calcination section has a second hydraulic diameter d h,2 . Second hydraulic diameter d h,2 Less than or equal to the first hydraulic diameter d h,1 Multiplied by the sine of the angle alpha.
d h，2 ≤d h，1 ·sin(α)
Hydrodynamic diameter d h Is four times the quotient of the flow cross section a transverse to the flow direction divided by the flow circumference P.
In tubular bodies in which there is a gas flow through the body as a whole, e.g. in a tubular first calcination section of radius r, the flow cross section A tube Equal to circular cross section A tube ＝π·r 2 And flow perimeter P tube Equal to circumference P of circle tube =2·pi·r. Thus, the hydrodynamic diameter of the tube is d h,tube =2·r, and thus is the diameter of the tube. For other geometries, feature lengths are similarly obtained.
At a second hydraulic diameter d h,2 It must be noted that when solid fuel is intended to be used, this forms a solid bed within the second calcination section, which in turn results in that in conventional operation not the entire cross-sectional area of the second calcination section, but only the size of the solid fuel bed, is reduced for the gas flow. In the context of the present invention, a solid bed is understood to mean all types of layers of solid material including a pile or a poured layer. Likewise, the flow perimeter P is not the perimeter of the second calcination section, but rather the perimeter P through which the gas stream flows through the fuel bed and the upper portion of the second calcination section. However, if a liquid fuel is used, for example a high viscosity oil residue, its film thickness may be negligible in some cases, so the geometry of the second calcination section may be used as a suitable approximation in such cases.
An advantage of the apparatus according to the invention is that by adjusting the cross section according to the angle α of the second calcination section, the flow velocity in the flow direction is increased such that the velocity component in the z-direction (i.e. perpendicular to the earth's surface) is at least equal to the flow velocity in the vertical first calcination section. Since the velocity component in the z-direction in the second calcination section is thus at least as high as the velocity component in the z-direction in the first calcination section, the carrying capacity of the gas flow for the feedstock in both calcination sections is at least the same, and separation of the feedstock from the gas flow in the obliquely arranged second calcination section can be avoided. This means that no mineral raw material is lost due to deposition on or in the solid fuel. Due to the narrowing in the second calcination section and thus the overall higher flow velocity, the effect of reducing the velocity component in the z-direction in the second calcination section is at least compensated for by the oblique arrangement and thus, according to the invention, by the diameter d h The bearing capacity remains at least constant in relation to the angle alpha.
In another embodiment of the invention, the first and second calcination sections are configured with a flow of gas flowing through the first and second calcination sections from bottom to top.
In another embodiment of the invention, the first calcination section is arranged below the second calcination section. Preferably, the first calcination section is arranged directly adjacent to the second calcination section.
In another embodiment of the invention, the apparatus includes a third calcination section. The third calcination section is vertically arranged. The third calcination section is disposed above the second calcination section. Preferably, the second calcination section is arranged directly adjacent to the third calcination section.
In another embodiment of the invention, the second calcination section has a first and second raw material feeder. The first second raw material feeder is arranged in the lower 20% of the second calcination section, i.e. at the inlet for the gas stream. The first and second raw material feeders supply raw materials into the air flow of the second calcination section from above or supply raw materials into the air flow of the second calcination section from the side. The raw material for the calciner is in particular a material for heat treatment which has been preheated in a preheater, for example and preferably a coarse material for clinker production. This should also include arranging the first and second feedstock feeders in the first calcination section immediately upstream of the second calcination section.
The first calcination section also typically has at least a first raw material supply. The raw material is thus usually and preferably supplied to the calciner in the form of sub-portions to achieve a spatial distribution of the decarbonizing over the calciner and thus also a distribution of the energy consumption within the calciner. In the case of nebulizable fuel, this takes place spatially adjacently. Thus, a first sub-quantity of raw material is supplied via a first raw material supply and a second sub-quantity is supplied via a first second raw material supply.
Accordingly, the third calcination section may preferably have at least a first third raw material feeder arranged therein.
In a further embodiment of the invention, the second calcination section additionally has a second raw material supply. A second raw material feeder is arranged in the middle region of the second calcination section, wherein the second raw material feeder supplies raw material into the gas flow of the second calcination section from above or into the gas flow of the second calcination section from the side. As a result, the raw materials are supplied in a larger spatial distribution, which also results in energy consumption caused by decarbonization taking place with a larger spatial distribution, leading to homogenization of the temperature and thus to uniformity of the reaction conditions. It goes without saying that the second calcination section can also have a further second raw material supply to achieve further homogenization. Preferably, the supply of raw material takes place in a constant manner via the first second raw material supply, and the second raw material supply is variably used in order to adapt the supply of raw material dynamically, in particular to the normally varying energy released from the alternative fuel. Thus, in the case of an alternative fuel having a relatively low heating value, less raw material will be supplied via the second raw material feeder, and in the case of an alternative fuel having a higher heating value, more raw material will be supplied via the second raw material feeder.
In a further embodiment of the invention, the second calcination section additionally has a third second raw material supply. A third second raw material feeder is arranged in the upper 20% of the second calcination section, wherein the third second raw material feeder supplies raw material into the gas flow of the second calcination section from above or into the gas flow of the second calcination section from the side. As a result, the raw materials are supplied in a larger spatial distribution, which also results in energy consumption caused by decarbonization taking place with a larger spatial distribution, leading to homogenization of the temperature and thus to uniformity of the reaction conditions. It goes without saying that the second calcination section can also have a further second raw material supply to achieve further homogenization.
In another embodiment of the invention, a second fuel supply for solid fuel is arranged at the upper end of the second calcination section. For example and preferably, the alternative fuel may be supplied via a second fuel supply. Examples of alternative fuels include household, industrial or commercial waste, scrap tires, sewage sludge, and biomass. The heating value of the alternative fuel may vary widely. Thus, alternative fuels may also be introduced as a mixture of different fractions to achieve a certain heating value. This also allows for cost optimization, since fractions with lower heating value and coarser size distribution are generally cheaper. The inclined arrangement of the second calcination section thus also makes it possible to burn the non-nebulizable alternative fuel directly in the calciner in the immediate vicinity of the chemical reaction of the raw material, to provide the product and thus the energy close to its reaction. In order to allow better combustion of some alternative fuels, the underside of the second calcination section may be stepped, or the underside of the second calcination section may have a grate that moves forward or backward, wherein the grate that moves forward or backward may also be stepped. In the context of the present invention, the underside is the floor, i.e. the area along which solids will slide due to gravity. Similarly, the upper and lateral sides will be the portions that restrict the airflow in an upward or lateral direction.
In a further embodiment of the invention, the second calcination section has an angle α between the horizontal plane and the flow direction of the second calcination section, wherein the angle α is between 30 ° and 70 °, preferably between 35 ° and 60 °, more preferably between 40 ° and 55 °, particularly preferably between 40 ° and 50 °. Here, the optimal value should be selected. The steeper the second calcination section, the greater the velocity component of the gas stream in the z-direction, and the more readily the particles remain in the gas stream. On the other hand, a flat construction is particularly advantageous for alternative fuels with a coarse size distribution and/or a high moisture content.
In another embodiment of the invention, the second calcination section is arranged below the first calcination section, and the controllable bypass is arranged in parallel with the second calcination section. The lower end of the second calcination section may also be aligned with the first calcination section, for example. In this case, the upper end of the second calcination section and the lower end of the first calcination section are connected to each other, for example, by means of a horizontal connection, wherein the controllable bypass is then arranged directly below the first calcination section vertically.
In another aspect, the invention relates to a method for operating an apparatus for heat treating a mineral feedstock. Preferably a method of operating an apparatus for producing cement clinker. However, the apparatus may also be used for heat treatment of clay or e.g. lithium ores. Hereinafter, cement clinker production is used as an example. The method is carried out in an apparatus comprising a calciner having a vertical first calcinerA section and an inclined second calcination section. The method is preferably performed in an apparatus according to the invention. During operation, the gas stream passes through the first calcination section and the second calcination section. For example and preferably, the gas stream originates from a rotary kiln. For example and preferably, the gas stream contains mainly oxygen and, in addition, CO produced in the rotary kiln by combustion and residual deacidification of the feedstock 2 (typically about 10% of the total deacidification). The gas stream preferably contains less than 20% by volume of nitrogen, particularly preferably less than 15% by volume of nitrogen, preferably about 50 to 70% by volume of oxygen. The above values refer to dry gas, i.e. without taking into account water. Preferably, the incoming gas stream includes sufficient oxygen to combust the fuel supplied to the calciner. According to the invention, the apparatus is operated such that at any point in the second calcination section the froude number Fr is equal to or greater than the minimum froude number Fr in the first calcination section. The Froude number Fr is the vertical direction v of the air flow z The velocity component of the upper divided by the gravitational acceleration g and the hydraulic diameter d h Square root of the product of (2).
Wherein:
the hydraulic diameter is four times the quotient of the flow cross section a perpendicular to the flow direction divided by the flow circumference P.
In the vertical first calcination section, the gas flow is in the vertical direction v z The upper velocity component is equal to the flow velocity v of the gas stream, whereas in the inclined second calcination section the angle α has to be taken into account. In this case, the air flow is in the vertical direction v z The upper velocity component is the sine of the velocity of the airflow v multiplied by the angle α.
v z ＝v·sin(α)
However, it is necessary to consider that the flow rate is not a constant. The flow rate in the calciner is varied by various processes. For example, temperature differencesResulting in a discrepancy. In areas with higher temperatures, the gas wants to occupy more space, increasing the velocity v. Likewise, deacidification of the feedstock results in CO 2 This increases the amount of material and thus also the flow rate. The fuel may also cause an increase in the amount of material, for example due to water released or formed during combustion. These effects mean that the froude number is not constant at a constant geometry within the calcination section, but differs depending on the location.
Since the froude number is considered a measure of the carrying capacity of the gas stream for the feedstock in solid form and the carrying capacity in the second calcination section must be at least as high as in the first calcination section, the froude number in the second calcination section must be everywhere greater than the minimum froude number in the first calcination section. However, it has to be considered that the inclination angle α does not lead to the entire flow velocity v, but only its z-component v z Is input into the calculation and also contributes only to the carrying capacity. The emphasis is only on the minimum in the first calcination section, since the loading capacity here must also be sufficient. If the geometry in the first calcination section is assumed to be constant, the Froude number is increased (e.g., by CO during deacidification 2 Release of (c) will result in locally higher values.
The calciner is particularly preferably operated with turbulent flow. As a result, the velocity profile of the stream exhibits only small variations in the width of the stream. In the case of laminar flow, the velocity of the air flow has a distribution over the width which is zero at the edges and has a maximum in the middle. This will make the carrying capacity location dependent, complicating the method management.
In another embodiment of the invention, the calciner is operated at an atmosphere comprising less than 25% nitrogen, preferably comprising less than 15% nitrogen, more preferably comprising less than 10% nitrogen, particularly preferably comprising less than 5% nitrogen.
In another embodiment of the invention, the froude number in the second calcination section is selected to be greater than 0.7, preferably greater than 2. Furthermore, the froude number in the second calcination section is selected to be less than 9, preferably less than 4.
In another embodiment of the invention, in the second calcination section, the raw material is supplied at least two locations via a first and a second raw material feeder. This occurs at intervals from each other along the flow direction. This achieves homogenization of the reaction and thus of the energy consumption and of the temperature.
In another embodiment of the invention, solid fuel is supplied and combusted in the second calcination section. For example and preferably, the alternative fuel may be supplied via a second fuel supply. Examples of alternative fuels include household, industrial or commercial waste, scrap tires, sewage sludge, and biomass. The heating value of the alternative fuel may vary widely. Thus, alternative fuels may also be introduced as a mixture of different fractions to achieve a certain heating value. This also allows for cost optimization, as the fraction with the lower heating value is generally cheaper. The inclined arrangement of the second calcination section thus also makes it possible to burn the non-nebulizable alternative fuel directly in the calciner in the immediate vicinity of the chemical reaction of the raw material, to provide the product and thus the energy close to its reaction. In order to allow better combustion of some alternative fuels, the underside of the second calcination section may be stepped, or the underside of the second calcination section may be conveyed using a forward or backward moving grate, wherein the forward or backward moving grate may also be stepped.
In a further embodiment of the invention, a solid fuel is supplied in the second calcination section, at least 90% of the fuel mass of which has a block size of more than 50mm, preferably more than 70mm, particularly preferably 100 mm.
In another embodiment of the invention, an nebulizable fuel is supplied in the first calcination section. Furthermore, the raw material is supplied in the first calcination section via a first raw material feeder. The fuel and the feedstock are preferably supplied spatially adjacent to each other to provide a spatial connection between energy production and energy consumption.
Drawings
The device according to the invention is elucidated in more detail below with reference to the working examples shown in the drawings.
Fig. 1 is an apparatus for the heat treatment of mineral raw materials.
Fig. 2 is a first exemplary calciner.
Fig. 3 is a second exemplary calciner.
Fig. 4 is a third exemplary calciner.
Fig. 5 is a fourth exemplary calciner.
All illustrations are purely diagrammatic and not to scale and serve only to clarify the features of the invention.
Detailed Description
Fig. 1 shows an apparatus for the heat treatment of mineral raw materials, such as a plant for producing cement clinker. The facility includes a preheater 100, a calciner 110, a rotary kiln 120, and a cooler 130. The material, for example raw meal made of limestone, is applied at the top, passes through the plant in the described order and can be discharged as clinker from the cooler 130. The gas stream enters the calciner 110 from the rotary kiln 120 and thus enters the preheater 100 counter-currently to the material stream.
Thus, in the four exemplary calciner embodiments shown below, the air flow enters from below and flows upward from the direction of the rotary kiln 120. The calciner 110 has at least one cyclone, not shown in the example, at the upper end respectively.
Hereinafter, the same reference numerals are used for the same elements, and differences between the embodiments are described in detail in the specification.
Fig. 2 shows a first calcination section 10 arranged vertically, a second calcination section 20 inclined at an angle of 45 ° above it, and a third calcination section 30 arranged above it Fang Shuzhi. The first calcination section 10 has a first fuel supply 12 for an nebulizable fuel (e.g. coal dust) and a first raw material supply 14 for supplying raw material from the preheater 100. The combustion of the fuel in the first calcination section 10 forms energy for deacidification of the feedstock, thereby producing CO 2 . In the second calcination section 20, the solid fuel is supplied from above by a second fuel supply 22, for example via a screw, and then the fuel is burned on the inclined surface of the second calcination section 20. Combustion residues, e.gThe metal component, such as fuel, falls through the first calcination section 10 and can then be discharged below it. The second calcination section 20 also includes a first and second raw material supply 24, through which the raw material from the preheater can likewise be added. Disposed above the second calcination section 20 is a third calcination section 30 comprising a third fuel supply 32 and a first third raw material supply 34.
As shown in fig. 2, the cross-section of the second calcination section 20 is smaller than the cross-section of the first calcination section 10. For example, the cross-section is about 30% smaller than the cross-section of the first calcination section 10, which corresponds to a sine of 45 °.
In the second embodiment of the calciner 110 shown in fig. 3, the second calcination section 20 comprises, in addition to the first embodiment shown in fig. 2, a second raw material supply 26, which makes it possible to achieve a better homogenization of the energy consumption and thus of the temperature in the second calcination section 20.
In a third embodiment of the calciner 110 shown in fig. 4, the second calcination section 20 has a step 21 for the combustion of the solid fuel. The step 21 may be horizontal as in the example shown, but the step 21 may also be inclined in or against the flow direction.
The fourth embodiment of the calciner 110 shown in figure 5 has a significantly different configuration. The gas stream is initially split and only a side stream passes through the second calcination section 20. The additional split flows through the second calcination section via the bypass and flow control valve 42 and is recombined with the gas flow leaving the second calcination section 20 before passing into the first calcination section 10.
Reference numeral table
10. First calcination section
12. First fuel feeder
14. First raw material feeder
20. Second calcination section
21. Step
22. Second fuel feeder
24. First and second raw material feeders
26. Second raw material feeder
30. Third calcination section
32. Third fuel feeder
34. First and third raw material feeder
40. Bypass path
42. Flow control valve
100. Pre-heater
110. Calcining furnace
120. Rotary kiln
130. Cooling device
Claims (17)
1. An apparatus for heat treatment of mineral raw material, wherein the apparatus comprises a calciner (110), wherein the calciner (110) comprises at least a first calcination section (10) and a second calcination section (20), wherein the first calcination section (10) is arranged vertically, wherein the second calcination section (20) is arranged obliquely, wherein the second calcination section (20) has an angle α between a horizontal plane and a flow direction of the second calcination section (20), wherein the angle α is between 20 ° and 80 °, wherein the first calcination section (10) has a first hydraulic diameter d h,1 Wherein the second calcination section (20) has a second hydraulic diameter d h,2 Wherein the second hydraulic diameter d h,2 Less than or equal to the first hydraulic diameter d h,1 Multiplying by the sine of said angle alpha.
2. The apparatus of claim 1, wherein the first calcination section (10) and the second calcination section (20) are configured to have an air flow through the first calcination section and the second calcination section from bottom to top.
3. The apparatus according to any one of the preceding claims, characterized in that the first calcination section (10) is arranged below the second calcination section (20).
4. The apparatus according to any one of the preceding claims, characterized in that the apparatus comprises a third calcination section, wherein the third calcination section is arranged vertically, wherein the third calcination section is arranged above the second calcination section (20).
5. The apparatus according to any of the preceding claims, characterized in that the second calcination section (20) has a first second raw material feeder (24), wherein the first second raw material feeder (24) is arranged in the lower 20% of the second calcination section (20), wherein the first second raw material feeder (24) supplies raw material into the gas flow of the second calcination section (20) from above or into the gas flow of the second calcination section (20) from the side.
6. The apparatus according to claim 5, characterized in that the second calcination section (20) has a second raw material supply (26), wherein the second raw material supply (26) is arranged in an intermediate region of the second calcination section (20), wherein the second raw material supply (26) supplies raw material into the gas flow of the second calcination section (20) from above or into the gas flow of the second calcination section (20) from the side.
7. The apparatus according to any one of the preceding claims, characterized in that a second fuel supply (22) for solid fuel is arranged at the upper end of the second calcination section (20).
8. The apparatus according to any one of the preceding claims, characterized in that the lower side of the second calcination section (20) is stepped.
9. The apparatus according to any one of the preceding claims, characterized in that the underside of the second calcination section (20) has a grate that moves forward or backward.
10. The apparatus according to any of the preceding claims, characterized in that the second calcination section (20) has an angle α between the horizontal plane and the flow direction of the second calcination section (20), wherein the angle α is between 30 ° and 70 °, preferably between 35 ° and 60 °, more preferably between 40 ° and 55 °, particularly preferably between 40 ° and 50 °.
11. The apparatus according to any of the preceding claims, characterized in that the second calcination section (20) is arranged below the first calcination section (10) and that a controllable bypass (40) is arranged in parallel with the second calcination section (20).
12. A method for operating an apparatus for heat treatment of a mineral raw material, wherein the method is performed in an apparatus comprising a calciner (110), the calciner (110) having a vertical first calcination section (10) and an inclined second calcination section (20), wherein during operation an air flow is caused to pass through the first calcination section (10) and the second calcination section (20), wherein the apparatus is operated such that the froude number is the square root of the product of the velocity component of the air flow in the vertical direction divided by the gravitational acceleration g and the hydraulic diameter, wherein the hydraulic diameter is the flow cross section perpendicular to the flow direction divided by the flow circumference, wherein the froude number at any point in the second calcination section (20) is equal to or greater than the smallest froude number in the first calcination section (10).
13. The method according to claim 12, characterized in that the calciner (110) is operated at an atmosphere comprising less than 25% nitrogen, preferably comprising less than 15% nitrogen, more preferably comprising less than 10% nitrogen, particularly preferably comprising less than 5% nitrogen.
14. The method according to any one of claims 12 to 13, wherein the froude number in the second calcination section (20) is selected to be greater than 0.7, preferably greater than 2, wherein the froude number in the second calcination section (20) is selected to be less than 9, preferably less than 4.
15. The method according to any one of claims 12 to 14, characterized in that in the second calcination section (20) raw materials are supplied at least two locations via a first second raw material feeder (24) and a second raw material feeder (26) spaced apart from each other along the flow direction.
16. The method according to any one of claims 12 to 15, characterized in that solid fuel is supplied in the second calcination section (20), at least 90% of the fuel mass of which has a block size of more than 50mm, preferably more than 70mm, particularly preferably 100 mm.
17. The method according to any one of claims 12 to 16, characterized in that an nebulizable fuel is supplied in the first calcination section (10) and a raw material is supplied in the first calcination section (10) via a first raw material feeder (14).
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102021203071.8 | 2021-03-26 | ||
| DE102021203071.8A DE102021203071A1 (en) | 2021-03-26 | 2021-03-26 | Device and method for the thermal treatment of a mineral starting material |
| BEBE2021/5236 | 2021-03-26 | ||
| PCT/EP2022/057196 WO2022200219A1 (en) | 2021-03-26 | 2022-03-18 | Device and method for the thermal treatment of a mineral feedstock |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117062789A true CN117062789A (en) | 2023-11-14 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202280024717.2A Pending CN117062789A (en) | 2021-03-26 | 2022-03-18 | Device and method for heat treatment of mineral raw materials |
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| Country | Link |
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| CN (1) | CN117062789A (en) |
| DE (1) | DE102021203071A1 (en) |
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|---|---|---|---|---|
| DE102022206778A1 (en) | 2022-07-01 | 2024-01-04 | Thyssenkrupp Ag | CO2-free production of artificial pozzolans, especially from clays |
| WO2024002927A1 (en) | 2022-07-01 | 2024-01-04 | thyssenkrupp Polysius GmbH | Co2-free production of artificial pozzolans, in particular from clay |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| DE102018206673A1 (en) | 2018-04-30 | 2019-10-31 | Thyssenkrupp Ag | Oxyfuel clinker production with special oxygen supply |
| DE102018206674A1 (en) | 2018-04-30 | 2019-10-31 | Thyssenkrupp Ag | Oxyfuel clinker production without recirculation of preheater exhaust gases |
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2021
- 2021-03-26 DE DE102021203071.8A patent/DE102021203071A1/en active Pending
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| DE102021203071A1 (en) | 2022-09-29 |
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