LU103008B1 - Avoidance of emissions during the production of artificial pozzolans from mineral materials, in particular clays - Google Patents

Abstract

The present invention relates to a device for thermal treatment, wherein the device has at least one preheater 10, a calciner 20 and a material cooler 30, wherein a solids stream is led into the preheater 10, from the preheater 10 into the calciner 20, from the calciner 20 into the material cooler 30 and out of the material cooler 30, wherein a gas stream is led into the material cooler 30, from the material cooler 30 into the calciner 20, from the calciner 20 into the preheater 10 and out of the preheater 10, wherein the device has a combustion chamber 40, wherein the gas stream from the material cooler 30 is led at least partially through the combustion chamber 40 into the calciner 20, characterized in that a residence time device 50 is arranged between the combustion chamber 40 and the calciner 20.

Description

thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 1/12

Avoidance of emissions during the production of artificial pozzolans from mineral materials, in particular clays

The invention relates to a device and a method with which a

Exhaust gas treatment to convert pollutants is already possible within the process and thus without downstream exhaust gas treatment, which in turn

Reduces or avoids energy consumption for exhaust gas treatment.

When heating fuels are burned, nitrogen oxides, briefly summarized as NO, as well as partially unburned hydrocarbons and

Hydrocarbon-containing compounds, here and in the following for the sake of simplicity (and neglecting other heteroatoms) summarized as C,H,.NO, can be either non-catalytically (SNCR) or catalytically (SCR), especially with ammonia

NH; or urea to nitrogen. Hydrocarbon C,H, can be

Oxygen is converted to water and carbon dioxide. For this conversion, a

Temperature windows of over 800 °C make sense. Therefore, in exhaust gas treatment it is usually necessary to reheat the comparatively cold exhaust gases, which

consumes energy and often requires additional heat exchangers.

DE 102011014498 A1 describes a method for producing a

clinker substitute known.

A manufacturing process for synthetic pozzolans is known from US 9458 059 B2.

The object of the invention is to save energy in the treatment of exhaust gases and thus to reduce further CO» emissions, for example from the combustion of fuels as

Heat source, to be avoided.

This object is achieved by the device with the features specified in claim 1

Features and by the method having the features specified in claim 20.

thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 2/12

Advantageous further developments result from the subclaims, the following

Description and drawing.

The device according to the invention is used for the thermal treatment of, for example, and in particular, mineral material, in particular clays, for the production of artificial pozzolans as an additive for cement clinker. Clays have increasingly established themselves as an important raw material in the cement industry, since their thermal

Treatment results in less or no CO being released from the raw material, as happens, for example, when limestone is burned. Since the temperature for the

However, since the activation of mineral materials, especially clays, can often be below 800 °C, the temperature inside the calciner is not sufficient to reliably convert pollutants. The device has at least one preheater, a

Calciner and a material cooler. The preheater is used as a

DC heat exchanger with cyclone separator or as a cascade of two to six

DC heat exchangers with cyclone separators. Alternatively, the

Preheater can also be designed as a cross-flow heat exchanger. The material cooler is also preferably designed as a direct current heat exchanger with cyclone separator or as

Cascade of two to six co-current heat exchangers with cyclone separators. Alternatively, the material cooler can also be designed as a cross-flow heat exchanger. A solids flow is fed into the preheater, from the preheater into the

Calciner, from the calciner into the material cooler and out of the material cooler. In countercurrent to this, a gas flow is fed into the material cooler, from the

Material cooler into the calciner, from the calciner into the preheater and from the

preheater. The device has a combustion chamber. The gas flow from the material cooler is at least partially led through the combustion chamber into the

Calciner. There can be another partial flow, which is, for example, led directly from the material cooler into the calciner, i.e. there is a combustion chamber bypass. In the combustion chamber, the combustion of natural gas, hydrogen, coal,

Ammonia or alternative fuels, such as biomass, old tires or household waste, provide the thermal energy required for the process. Such plants are known for the thermal treatment of mineral materials, especially clays.

thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 3/12

According to the invention, a

In the combustion chamber, pollutants such as NO are generated at the temperatures of combustion.

Hydrocarbons and hydrocarbon-containing compounds from the

Fuel can leak out. Usually the combustion chamber is either inside the

Calciners, for example in the case of natural gas firing or directly on the calciner, especially for substitute fuels. The direct connection ensures that heat losses are avoided and also saves

Investment costs and installation space. Therefore, it does not seem advantageous to

to spatially separate the combustion chamber and the calciner and to create a

However, this makes it possible to treat the exhaust gases from the combustion chamber at an ideal temperature level, thus saving subsequent and energy-intensive exhaust gas treatment. The residence time device enables a separation of the temperatures for the

Exhaust gas treatment in the residence time device and the thermal treatment, for example of the clay, in the calciner can be achieved, which both for the

For exhaust gas treatment as well as for thermal treatment, a suitable

Temperature windows can be selected. In particular, the temperature in the

The dwell time device should be set higher than in the calciner, so that

Combustion of C,H, especially with oxygen or in the presence of, for example, ammonia NO, by synproportionation of NO, and NH; to

Nitrogen (and water) can be converted. The type of pollutants usually depends very much on the type of fuel used.

In a further embodiment of the invention, between the combustion chamber and the

Residence time device and/or an auxiliary combustion device is arranged in the residence time device. This embodiment is preferred if the combustion chamber is

Combustion of substitute fuels. Substitute fuels usually have a greater fluctuation in calorific value. The auxiliary combustion device is preferably designed to burn a fuel that enables rapid and specifically adjustable combustion. The auxiliary combustion device is preferably designed to burn a fuel that is selected from the group thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 4/12 comprising coal dust, natural gas, hydrogen, biogas and ammonia. It is thus possible to compensate for temperature fluctuations caused by fluctuations in the fuel in the

Combustion chamber, precisely and quickly compensate for the

A stable temperature is ensured by the residence time device and thus the process of pollutant degradation takes place reliably.

In a further embodiment of the invention, the dwell time device is tubular. For example, the tubular dwell time device can be gooseneck-shaped. Likewise, the tubular

The dwell time device can be designed as an expanded pipe.

Residence time device can optionally be equipped with one or more flow internals to improve intensive mixing of the gas within the device.

In a further embodiment of the invention, between the combustion chamber and the

A first reactant feed is arranged in the residence time device. The

Reactant supply is used to supply a reactant for the conversion of pollutants. Since the pollutants to be treated are very different from the

combustion chamber, the reactant and thus the first reactant feed must be selected depending on the fuel to be used in the combustion chamber.

In a further embodiment of the invention, the first reactant supply is for supplying oxygen, for example in the form of air or

Material cooler preheated air. Oxygen is required as a reactant for the conversion of hydrocarbon C,H, into water and carbon dioxide.

In a further embodiment of the invention, the first reactant supply is for supplying different types of reducing agents, for example ammonia,

Urea, their compounds or solutions, especially aqueous solutions, formed from them. Ammonia or urea can synproportionate with nitrogen oxides NO to form nitrogen.

thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 5/12

In a further embodiment of the invention, the device has at least one first NO, analyzer. The NO, analyzer serves to detect the NO,

Concentration. Usually, a device using infrared spectroscopy is used as the NO, analyzer. In one embodiment, the at least one first NO, analyzer is in the residence time device or between the

The residence time device and the calciner are arranged. This has the advantage of immediate feedback and faster controllability. Additionally or alternatively, the at least one first or a second NO, analyzer can be arranged in or behind the

The advantage of this embodiment is that the gases are significantly cooler here, which simplifies the measurement. The at least one first or second NO, analyzer can also be arranged after the calciner or even after the preheater, since in these the temperature for the formation of NO, should no longer be high enough, so that this value for the NO, content in the

Residence time device is meaningful.

In a further embodiment of the invention, the device has at least one first NHz analyzer. The NHz analyzer serves to detect the NHz

Concentration in the gas stream. Preferably, several NHz analyzers are used to determine the concentration at different points along the exhaust gas stream. The or at least two NHz analyzers are located, for example, at different levels of the calciner and regulate/control the

Addition of the reactant to determine the utilization of the reactant and thus ensure effective use of the reactant. The at least one

NHz analyzer, preferably the at least two NHz analyzers, are located, for example and preferably, in spatial proximity to the at least one NO analyzer and/or at least one temperature sensor. The NHz

Analyzers are connected to corresponding containers, preferably to at least one container for ammonia, via at least one dosing system. For example, ammonia can be injected into the gas stream at different locations and/or levels in the same or different amounts and/or concentrations.

thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 6/12

In a further embodiment of the invention, the device has at least one first control device. The at least one first control device is for

Reading the at least one first NO, analyzer. The at least one first control device is designed to control the first reactant supply and/or an optional second reactant supply depending on the NO, value detected by at least one first NO, analyzer and regulates the first reactant supply and/or the optional at least one further reactant supply, preferably in different

levels and/or with several nozzles, depending on the detected NO, value.

This makes it possible to add the reactant, for example ammonia, in a targeted manner, which in turn prevents an overdose of the reactant and the associated emission of ammonia, for example.

In a further embodiment of the invention, the device has at least one first control device. The at least one first control device is for

Reading the at least one first NHz analyzer. The at least one first control device is designed to control the first reactant supply and/or at least one further reactant supply depending on the NHz value detected by at least one first NHz analyzer and regulates the first reactant supply and/or the at least one optional second

Reactant supply depending on the recorded NH3 value. This enables a targeted addition of the reactant, for example ammonia, which in turn can prevent an overdose of the reactant and the associated emission of ammonia, for example.

In a further embodiment of the invention, the device comprises a

Temperature sensor. Temperature sensor is to be understood broadly in the sense of the invention and includes any sensor system for temperature detection. The temperature sensor can be a thermocouple. Alternatively, a temperature sensor can also be an acoustic

Sensor that measures the temperature over a spatial distance by means of the

The temperature sensor is preferably located in the first

Combustion chamber, in the residence time device or between the combustion chamber and the thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 7/12

The device can also have several

Temperature sensors, particularly at the aforementioned positions.

In a further embodiment of the invention, the device has at least one first control device. The at least one first control device is for

Reading the temperature sensor or the temperature sensors. The at least one first control device is designed to control the first

Reactant supply and/or at least an optional second

reactant supply and/or the auxiliary combustion device depending on the temperature detected by the temperature sensor. This enables a targeted

Addition of a fuel is possible, which in turn allows an exact adjustment of the

Temperature to the desired temperature window is possible.

In a further embodiment of the invention, the first reactant supply is designed for a supply with a pressure of 0.5 bar to 5 bar.

In a further embodiment of the invention, adjacent to the first

A first water supply is arranged in the reactant supply. The

Water injection through the water supply can be used for targeted temperature adjustment in order to optimally set the temperature level for pollutant minimization. The water supply is usually not only used to supply

Water, usually aqueous solutions, especially process waste water, are used, which may additionally contain other substances. Preferably, the

The calorific value of the other substances is not so high that the cooling effect caused by the evaporation of the water is compensated. For example, aqueous solutions with a proportion of organic compounds can be used here, since the organic compounds are safely converted under the prevailing conditions.

In a further embodiment of the invention, the device has at least one first control device. The at least one first control device is for

Reading the temperature sensor or the temperature sensors. The thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 8/12 at least one first control device is designed to control the water supply in

Dependence on the temperature detected by the temperature sensor.

This allows a targeted adjustment of the temperature to the desired

Temperature window possible.

In a further embodiment of the invention, the dwell time device has a

Long, so that the residence time in the residence time device is between 0.5 s and 10 s, in particular between 1 s and 5 s, particularly preferably from 1.5 s to 2.5 s.

This creates a suitable window between sufficient reaction time and

Heat loss and flow resistance are achieved.

In a further embodiment of the invention, between the calciner and the

A reduction device is arranged in the material cooler. A reduction device is used to treat the thermally treated material in a reducing atmosphere, in particular for color optimization. To form the reducing atmosphere, gases, solids and/or liquids can be used, for example, which contain carbon, hydrogen, nitrogen, carbon monoxide or the like or corresponding compounds thereof, for example methane or ammonia or

Mixtures thereof as well as inert gases, especially nitrogen. The reducing atmosphere can also be a substoichiometric

combustion (oxygen deficiency). For example, this can

Fe to Fe", which results in a reduction in the color of the product and thus increased market acceptance.

In a further embodiment of the invention, the dwell time device has a

Catalyst. The catalyst is, for example, a platinum-rhodium catalyst, which is suitable for the conversion of NO, and NH; to nitrogen.

In a further embodiment of the invention, the dwell time device has at least one deflection. Alternatively or additionally, the

The dwell time device has flow fittings for gas mixing. In particular, the dwell time device can be designed in the shape of a gooseneck. In addition to the compact spatial arrangement, the deflections lead to mixing. In addition, height differences can also be compensated for, which enables a compact

Construction method favored.

In a further embodiment of the invention, the residence time device has at least one second reactant feed. The at least second

Reactant supply is arranged between the combustion chamber and the residence time device or at the residence time device and preferably with an optional

control device. In a first case, the first

Reactant supply and the at least second reactant supply for

supply of the same reactant. For example, both can be used for

supply of ammonia. In particular, the first

Reagent supply and the at least second reactant supply are spaced apart from each other. This allows the concentration, for example of the

ammonia for NO, degradation, can be kept more constant. In a second case, the first reactant supply serves to supply a first reactant, for example NH; for NO, degradation, and the at least second

Reactant supply for supplying at least a second reactant, for example O or air for the C,H, degradation.

In a further embodiment of the invention, the device comprises an SCR

reactor, with the SCR reactor located in the gas stream behind the preheater.

The SCR reactor can be used in particular as a backup solution. As long as the NO reduction according to the invention is sufficient, the SCR reactor is not operated, for example, thus saving the necessary energy.

In a further embodiment of the invention, the device has a bypass, wherein the bypass is arranged between the combustion chamber and the calciner. The

The bypass is arranged parallel to the dwell time device in terms of flow. Thus, a first partial flow is led through the dwell time device and a second partial flow is led through the bypass. This allows for optimal use of the permissible

Emissions possible.

thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 10/12

In a further aspect, the invention relates to a method for operating a device according to the invention. The temperature in the dwell time device is selected between 750 °C and 1300 °C. In particular, the temperature in the

Residence time device between 800 °C and 1100 °C, particularly preferably between 900 °C and 1050 °C.

In a further embodiment of the invention, a thermal treatment of mineral material, in particular clays or clay-like substances, is carried out.

The device according to the invention is explained in more detail below using an embodiment shown in the drawing.

Fig. 1 Device

An exemplary device is shown schematically in Fig. 1. The material to be treated

Material, for example a clay, is fed to the preheater via a material feed 110, preheated and introduced into the calciner 20, where it is thermally treated.

From the calciner 20, the material is fed into an optional reduction device 100, where it is particularly color-optimized and then passes into the material cooler 30, from which the finished product is then removed via a product removal device 120. In countercurrent, the gas is first fed into the material cooler 30 via a gas supply 130 and is heated there by the product to be cooled. The heated gas passes into the

Combustion chamber 40. A substitute fuel, such as garbage, is burned there. During combustion, the temperature and the

presence of nitrogen and oxygen nitrogen oxides are formed. Combustion chamber (40) and

Residence time device (50) are preferably equipped with temperature sensors.

Furthermore, the gases are hottest when they leave the combustion chamber 40, so this is the ideal time to decompose the nitrogen oxides. To compensate for fluctuations in the calorific value of the secondary fuel, the device has a

Auxiliary combustion device 60 (optionally several auxiliary combustion devices 60) which is operated with gas, liquid fuel or coal dust, for example, and is thus able to reliably adjust the temperature. In addition, the system has a

Water supply 62, with which water can be supplied and thus the temperature can be reduced in a simple manner. The combination of auxiliary combustion device 60 and water supply 62 thus provides the possibility of a particularly targeted

Temperature setting. In addition, a first reactant feed 70 is used to

Ammonia solution is injected. This allows a

Reaction between NO, and NH; at 1000 °C, for example. To

To complete the conversion and not to produce an excess of ammonia (and thus introduce a new source of pollutants), the device has a second reactant feed 72, in which at a later point in the

Ammonia solution is injected again into the dwell time device 50. In addition, the

A NO2 analyzer (80) and a NH2 analyzer (82) are arranged in the residence time device.

In addition, a NO, analyzer 80 and an NH> analyzer (82) are arranged after the preheater. The NO, analyzers 80 and the NH2 analyzers (82) are connected to a first control device 90, which, depending on the NO, content detected by the NO, analyzer 80 and the NH,; content detected by the NHs analyzer as well as the

Temperature sensors record the temperature levels, which regulate the injection of ammonia solution through the first reactant feed 70 and the second reactant feed 72. From there, the warm gas, but freed from NO, and with only small

Contained in NH, in the calciner 20. The calciner can be operated at 750 °C for certain products, for example, which would be too low to convert NO, within the calciner 20. From the calciner 20, the gas is fed into the

preheater 10, where it transfers its heat to the supplied material. The

Exhaust gas from the preheater 10 is then discharged via a gas outlet 140 and can be subjected to further treatment, for example for dedusting.

Reference symbols

Preheater

Calciner

Material cooler

Combustion chamber thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 12/12

Residence time device 60 Auxiliary combustion device 62 Water supply 70 First reactant supply 72 Second reactant supply 80 NO, analyzer 82 NHz analyzer 90 Control device 100 Reduction device 110 Material supply 120 Product removal 130 Gas supply 140 Gas outlet

Claims (22)

thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 1/4 Patent claims 1. Device for the thermal treatment of mineral materials, the device having at least one preheater (10), a calciner (20) and a material cooler (30), a solids stream being led into the preheater (10), from the preheater (10) into the calciner (20), from the calciner (20) into the material cooler (30) and out of the material cooler (30), a gas stream being led into the material cooler (30), from the material cooler (30) into the calciner (20), from the calciner (20) into the preheater (10) and out of the preheater (10), the device having a combustion chamber (40), the gas stream from the material cooler (30) being led at least partially through the combustion chamber (40) into the calciner (20), characterized in that a residence time device (50) is arranged between the combustion chamber (40) and the calciner (20). 2. Device according to claim 1, characterized in that at least one auxiliary combustion device (60) is arranged between the combustion chamber (40) and the residence time device (50) and/or in the residence time device (50). 3. Device according to one of the preceding claims, characterized in that a first reactant supply (70) is arranged between the combustion chamber (40) and the residence time device (50). 4. Device according to claim 3, characterized in that at least the first reactant supply (70) is designed to supply ammonia, urea, their compounds or solutions thereof. 5. Device according to one of the preceding claims, characterized in that the device has at least a first NO analyzer (80). 6. Device according to claim 4 in combination with claim 5, characterized in that the device has at least one control device (90), wherein the at least one first control device (90) is designed to read out thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 2/4 the at least one first NO, analyzer (80), wherein the at least one first control device (90) is designed to control at least one first reactant feed (70) depending on the NO, value detected by at least one first NO, analyzer (80) by adjusting the type and/or amount and/or concentration of the reactant. 7. Device according to one of the preceding claims, characterized in that the device has at least one temperature sensor. 8. Device according to one of claims 3 to 6 in combination with claim 7, characterized in that the device has at least one first control device (90), wherein the at least one first control device (90) is designed to read the temperature sensor, wherein the at least one first control device (90) is designed to control at least one first reactant supply (70) and/or at least one auxiliary combustion device (60) and/or at least one water supply (62) depending on the temperature detected by the temperature sensor by adjusting the type and/or amount and/or concentration of the reactant. 9. Device according to one of the preceding claims, characterized in that the device comprises at least one NHz analyzer. 10. Device according to one of claims 3 to 8 in combination with claim 9, characterized in that the device has at least one control device (90), wherein the at least one first control device (90) is designed to read out the at least one first NHs analyzer (82), wherein the at least one first control device (90) is designed to control at least one first reactant supply (70) depending on the NHs value detected by at least one first NHs analyzer (82) by adjusting the type and/or amount and/or concentration of the reactant. thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 3/4 11. Device according to claim 10, characterized in that the reactant supply is/are attached to at least one addition point, preferably at least two addition points, in at least one height level, preferably in at least two different height levels. 12. Device according to one of claims 3 to 8, characterized in that the first reactant supply (70) is designed for a supply with a pressure of 0.5 bar to 5 bar. 13. Device according to one of claims 3 to 12, characterized in that at least one first water supply (62) is arranged adjacent to the first reactant supply (70). 14. Device according to one of the preceding claims, characterized in that the residence time device (50) has a length such that the residence time in the residence time device (50) is between 0.5 s and 10 s, in particular between 1 s and 5 s, particularly preferably from 1.5 s to 2.5 s. 15. Device according to one of the preceding claims, characterized in that a reduction device (100) is arranged between the calciner (20) and the material cooler (30). 16. Device according to one of the preceding claims, characterized in that the residence time device (50) comprises a catalyst. 17. Device according to one of the preceding claims, characterized in that the residence time device (50) has at least one deflection and/or flow internals for gas mixing. 18. Device according to one of the preceding claims, characterized in that the residence time device (50) has at least one second reactant supply (72), wherein the second reactant supply (72) is arranged between the combustion chamber (40) and the residence time device (50) or on the residence time device (50). thyssenkrupp Industrial Solutions AG 221313P00LU thyssenkrupp AG LU103008 4/4 19. Device according to one of the preceding claims, characterized in that the device comprises a catalytic reactor, wherein the catalytic reactor is arranged in the gas stream behind the preheater (10). 20. Method for operating a device according to one of the preceding claims, characterized in that the temperature in the residence time device (50) is selected between 750 °C and 1300 °C. 21. Method according to claim 20, characterized in that the temperature in the residence time device (50) is selected between 900 °C and 1050 °C. 22. Process according to one of claims 20 to 21, characterized in that a thermal treatment of clays or clay-like substances is carried out.