Method for thermally treating a mineral material in the cement, lime, residue and / or raw material industry for processing mineral raw materials using ammonia as main fuel

Abstract

The present invention relates to a method for thermally treating a mineral material in the cement, lime, residue and / or raw material industry for processing mineral raw materials, with ammonia being used as the main fuel, and the main fuel providing more than 50% of the thermal energy generated by combustion.

Description

[0001] Method for the thermal treatment of a mineral material in the cement, lime, residue and / or basic materials industry for processing mineral raw materials with ammonia as the main fuel

[0002] The invention relates to the use of ammonia as the main fuel in the cement, lime, residue and / or basic materials industry for processing mineral raw materials.

[0003] The cement, lime, waste, and / or raw materials industries, which process mineral raw materials, are comparatively energy-intensive and currently emit a high amount of the greenhouse gas carbon dioxide. For example, when limestone is burned to produce cement, up to 80% of the carbon dioxide originates from the limestone itself. The raw materials include limestone, clay, recycled concrete, or, more accurately, recycled cement paste, as well as other mineral raw materials. These are thermally treated to be used, for example, as binders or for further processing / refining. Fuels currently used include coal, pulverized coal, oil, or natural gas, as well as carbon-containing alternative fuels derived from waste or residues, although the trend toward the use of carbon-neutral alternative fuels is clearly evident. Nevertheless, it is foreseeable that, in the long term, a reliance on regeneratively produced fuels will be necessary.Three key energy carriers are currently being discussed: hydrogen produced using renewable energy, ammonia and methanol produced from this hydrogen, and biofuels. While the direct use of hydrogen would be energetically advantageous, its transport and storage are problematic due to safety concerns, high losses, and the fact that hydrogen, being a light gas, requires significant energy for compression. Therefore, many sectors of industry are currently grappling with the question of which energy carrier can best replace conventional energy sources in the future.

[0004] The object of the invention is to select suitable regeneratively produced energy carriers and advantageously integrate them into the processes of the cement, lime, residue and / or basic materials industries for processing mineral raw materials. This object is achieved by the method with the features specified in claim 1 and by the plant with the features specified in claim 23. Advantageous further developments are described in the dependent claims and the following description.

[0005] The process according to the invention serves for the thermal treatment of a mineral material in the cement, lime, waste, and / or basic materials industries for the processing of mineral raw materials. This includes, in particular, the production of clinker from limestone, but also, in particular, the production of, for example, cement-like additives (supplementary cementitious material), such as activated clays. Waste materials used here are primarily recycled concrete or recycled cementitious brick enriched from recycled concrete. Fuels are preferably used for the thermal treatment, as this allows heat generation to be directly combined with heat consumption for the thermal treatment. According to the invention, ammonia is used as the main fuel. Of the possible fuels, ammonia is particularly suitable for the cement, lime, waste, and / or basic materials industries for the processing of mineral raw materials.This has several reasons. Firstly, the cement, lime, residue, and / or basic materials industries often process mineral raw materials at high temperatures (up to 2000 °C), making the formation of nitrogen oxides a significant concern. The use of ammonia allows for the intrinsic removal of these nitrogen oxides. Furthermore, some raw materials, such as tones, may already contain ammonia, meaning that the plants are typically designed for ammonia reduction in the exhaust gas. Additionally, ammonia can be easily decomposed into its components, hydrogen and nitrogen, allowing for the production of at least some hydrogen, which is particularly useful for reducing metal oxides, for example, for color optimization.It is essential that ammonia is used as the primary fuel and not merely added for purposes such as NOx reduction or color optimization. A primary fuel, as defined by the invention, provides more than 50% of the thermal energy generated by combustion. This distinguishes ammonia as the primary fuel primarily from auxiliary fuels, which are often used to stabilize the ammonia flame and ensure safe combustion. These auxiliary fuels are used in smaller quantities, and their main function is not to contribute thermal energy, but rather to stabilize the combustion process. The primary fuel is therefore the fuel that contributes the majority of the thermal energy generated by combustion.'However, auxiliary fuels used to optimize combustion also contribute energy, meaning that ammonia does not provide all of the thermal energy generated by combustion, but "only" the majority. The overall process may also require additional electrical energy, for example for compressors, pumps, or control electronics, which is not supplied as thermal energy to the thermal treatment process.'

[0006] Preferably, the main fuel provides more than 80% of the thermal energy generated by combustion.

[0007] The NHs-containing compounds preferably have a calorific value of at least 15 MJ / kg, preferably at least 16.5 MJ / kg, and most preferably at least 18 MJ / kg.

[0008] Of the possible fuels, ammonia and, if necessary, gas mixtures produced from ammonia by (partial cracking) are suitable for the process.

[0009] In a further embodiment of the invention, at least one auxiliary fuel is used. The auxiliary fuel provides less than 25% of the thermal energy generated by combustion. This value can also be significantly lower, for example, below 5% or even below 1% of the thermal energy provided. The auxiliary fuel thus serves less as an energy carrier itself, but rather to support and stabilize the combustion of the ammonia. Ammonia tends to produce an irregular flame during combustion, which can lead to incomplete combustion.The auxiliary fuel is selected from the group comprising hydrogen, methane, natural gas, coal, oil, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methylpropan-2-ol, diethyl ether, 1,2-dimethoxyethane, 2-methoxy-2-methylpropane, 2-methoxy-2-methylbutane, tert-hexyl methyl ether, 2-ethoxy-2-methylpropane, 2-ethoxy-2-methylbutane, 2-[(propan-2-yl)oxy]propane, and alternative fuels, in particular biomass. Of these, coal and oil are the least preferred fossil fuels. In particular, the auxiliary fuel is selected from the group comprising methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methylpropan-2-ol, 2-methoxy-2-methylpropane, 2-methoxy-2-methylbutane, tert-hexyl methyl ether, 2-ethoxy-2-methylpropane, 2-ethoxy-2-methylbutane, and 2-[(propan-2-yl)oxy]propane. These auxiliary fuels have proven to be carbon-neutral when synthesized appropriately.

[0010] In a further embodiment of the invention, the ammonia is combusted within a temperature range of 800 °C to 1600 °C. This temperature range refers to the temperature in the combustion chamber and thus to the ambient temperature established by combustion for the thermal treatment. While it is advantageous to avoid excessively high temperature peaks in the flame in order to prevent unintended contact with the material being thermally treated, higher temperature peaks can occur in the flame, particularly in flame zones and also with fluctuations over time.

[0011] In a further embodiment of the invention, the ammonia is at least partially converted into hydrogen and nitrogen. This refers to a conversion occurring prior to combustion, not during combustion itself. This provides a hydrogen content of, for example, 5 to 10 vol%, ensuring clean and reliable combustion of the ammonia. The conversion can take place without a catalyst at comparatively higher temperatures or simply on a warm catalyst, since the equilibrium at low pressures lies on the side of the elements. In particular, the ammonia is converted into hydrogen and nitrogen to such an extent that the hydrogen content is 20 to 80 vol%, preferably 35 to 65 vol%, and particularly preferably 45 to 55 vol%. This content is significantly higher than the value required only for clean combustion.However, it has been found that this high water content, for example, produces a positive color effect when activating clays in the final product.

[0012] In a further embodiment of the invention, after at least partial splitting of ammonia into hydrogen and nitrogen, the hydrogen contained in the mixture can be separated from the mixture and subsequently added back in a controlled manner for the combustion of the ammonia.

[0013] In the following, "ammonia" will always include hydrogen produced from ammonia or a mixture of ammonia and such hydrogen. In these cases, energy is supplied to the process via the input of ammonia, even if the ammonia is modified or converted in the meantime.

[0014] In a further embodiment of the invention, the main fuel, ammonia, hydrogen produced from ammonia, or a mixture thereof, is combusted in a calciner or rotary kiln. The calciner, particularly a fluidized-flow calciner, has a high energy demand for the thermal treatment taking place there, so direct energy generation via combustion is advantageous, for example, and especially compared to electric heating. Combustion in an open flame is also advantageous in the rotary kiln, particularly since the temperatures required are comparatively high. Therefore, the direct combustion of the ammonia and / or the hydrogen produced from the ammonia is advantageous.

[0015] In a further embodiment of the invention, the main fuel ammonia, hydrogen produced from ammonia or a mixture thereof is used in a thermal reactor for the deacidification of iron ore or for the recycling of metal dusts, regardless of their chemical compounds.

[0016] In a further embodiment of the invention, the main fuel ammonia, hydrogen produced from ammonia, or a mixture thereof is used for processing construction waste, such as cleaning gravel of bitumen. In a further embodiment of the invention, the main fuel ammonia, hydrogen produced from ammonia, or a mixture thereof is used in a shaft kiln and / or multi-shaft kiln for burning limestone and dolomite to produce lime.

[0017] In a further embodiment of the invention, the main fuel ammonia, hydrogen produced from ammonia, or a mixture thereof is used to produce clinker from gypsum, in particular from waste gypsum. In this process, a portion of the main fuel can be converted from the driven-off SO3 to produce ammonium sulfate, thus buffering the corrosive properties of the SO3 load that would otherwise be generated in the process.

[0018] In a further embodiment of the invention, a gas stream with an oxygen content of more than 20 vol.%, preferably more than 22 vol.%, more preferably 25 to 80 vol.%, more preferably 35 to 80 vol.%, and particularly preferably 30 to 45 vol.%, is supplied to the main fuel. The increased oxygen content can influence the flame temperature and simultaneously stabilize the combustion of the ammonia and / or the NH3-containing compound. Furthermore, the amount of nitrogen introduced can also be reduced to simplify the subsequent separation of the carbon dioxide released from the mineral material.

[0019] In a further embodiment of the invention, combustion takes place in two stages at at least two locations arranged sequentially in the gas stream. For example, the first combustion occurs in a rotary kiln as a first location and in a calciner at a second location, which follows the first location in the gas stream. The main fuel, ammonia, is supplied to the first location in excess and superstoichiometrically to the available oxygen, preferably completely, in order to enable combustion at both the first and second locations. At the first location, only a deficit of oxygen is supplied, thus determining the proportion of ammonia that can be combusted there. At the second location, situated downstream of the first location in the gas stream direction, oxygen is added at least stoichiometrically. This allows the ammonia to be completely combusted at the second location, thereby releasing all the energy as thermal energy.Of course, the oxygen supply can also be superstoichiometric. This allows a reducing atmosphere to be created at the first location and between the first and second locations, and an oxidizing atmosphere at the second location. This can be useful, for example, in the treatment of clays, to first combust any volatile organic components that may be released from the clay at the second location (material flow countercurrent to the gas flow) and then to perform color optimization in a reducing environment at the first location.

[0020] In a further embodiment of the invention, a rotary kiln is chosen as the first combustion location and a calciner as the second location.

[0021] In a further embodiment of the invention, the concentration of ammonia, nitrogen oxides, oxygen, carbon monoxide, and / or hydrocarbons in the gas stream is detected. The amount of oxygen supplied to the combustion process is then regulated according to the detected concentration of ammonia, nitrogen oxides, oxygen, carbon monoxide, and / or hydrocarbons. This serves two purposes: firstly, to prevent ammonia, used as fuel, or hydrocarbons leaching from the material (e.g., clay), from being released unburned into the environment. Therefore, sufficient oxygen is supplied. Secondly, particularly in combustion processes occurring at at least two locations with different temperatures, a combustion with lower oxygen levels at higher temperatures can be advantageous for preventing nitrogen oxide formation or for its reduction through synproportionation.Furthermore, there may be areas where a concentration of carbon monoxide is desired, for example for color optimization, whereby the carbon monoxide in the gas flow should then be completely oxidized again.

[0022] In a further embodiment of the invention, the exhaust gases from the thermal process are fed into a grinding and / or drying process. The product of the grinding and / or drying process is thermally treated. This offers a number of advantages. An obvious advantage is the utilization of the waste heat. Furthermore, the material's ability to bind ammonia, in particular, can also be utilized, allowing it to be reintroduced into the combustion process. This results in both initial exhaust gas purification and an increase in the calorific value.

[0023] In a further embodiment of the invention, the main fuel is divided into at least a first partial fuel stream and a second partial fuel stream. The first partial fuel stream is combusted at a first location for thermal treatment, for example, in a rotary kiln. The second partial fuel stream is combusted at a second location for thermal treatment, for example, in a calciner. The second location is downstream of the first location in terms of gas flow. Combustion at the first location takes place at higher temperatures than at the second location. Due to the staged combustion at different temperatures, the nitrogen oxide produced at the first location at higher temperatures can be more effectively reacted with the reintroduced ammonia in the second combustion stage downstream of the gas stream and thus rendered harmless.

[0024] In a further embodiment of the invention, the main fuel is combusted with a swirling flame. The swirling flame serves to intensify combustion in turbulent flow, with the flame being stabilized by the swirl. In particular, the length, shape, and / or temperature are controlled by the swirl and divergence of the swirling flame. The swirling flame thus enables particularly precise control of the combustion and improves the mixing of the main fuel with the oxygen-containing combustion gas.

[0025] In a further embodiment of the invention, plasma-assisted start-up and / or ignition burners are used. These have proven to be particularly suitable for igniting ammonia.

[0026] In a further embodiment of the invention, a portion of the main fuel, ammonia, is used to reduce nitrogen oxides. One of the advantages of using ammonia as the main fuel is that it can also be used for the catalytic or, in particular, non-catalytic decomposition of nitrogen oxides. While this leads to a slight loss of calorific value due to synproportionation, it also results in improved exhaust gas purification. The reduction of nitrogen oxides is preferably carried out catalytically.

[0027] In particular, in a temperature range between 850 °C and 1100 °C, preferably in a temperature range between 950 °C and 1000 °C, the formation of nitrogen oxides is reduced by the non-catalytic reaction with ammonia.

[0028] Alternatively or additionally, an SCR catalyst can be provided for the selective catalytic reduction of nitrogen oxides. This preferably takes place in a temperature range between 150 °C and 650 °C, more preferably in a temperature range between 250 °C and 450 °C. This allows for an efficient reduction of the nitrogen oxide compounds formed.

[0029] Alternatively or additionally, an oxidation catalyst can be used, which is operated particularly in a temperature range between 100 °C and 650 °C, preferably in a temperature range between 250 °C and 500 °C, and is used to reduce incompletely converted ammonia, but also, for example, carbon-containing compounds released from clays.

[0030] Alternatively or additionally, a reaction to reduce incompletely reacted ammonia and / or nitrogen oxides and / or carbon-containing compounds can be carried out in a temperature range between 750 °C and 1150 °C, preferably in a temperature range between 850 °C and 950 °C, with an oxygen content of at least 2 vol% oxygen, preferably in a range between 4 vol% and 8 vol% oxygen.

[0031] In a further embodiment of the invention, a catalytic oxidation of the ammonia takes place after its combustion as the main fuel. The release of ammonia into the environment must be prevented, and oxidation, particularly according to the Ostwald process with extended contact time with nitrogen and water, represents a reliable method for preventing this emission.

[0032] In a further embodiment of the invention, the main fuel ammonia is used at least partially prior to combustion for reducing color optimization. This preferably takes place in a separate reactor for color optimization after thermal activation. Here, ammonia can be used, but preferably hydrogen produced from the ammonia, particularly catalytically, since the diffusion of the smaller hydrogen molecules is significantly faster.

[0033] In a further embodiment of the invention, the nitrogen oxides produced during the combustion of the main fuel are used for the production of nitric acid.

[0034] In a further aspect, the invention relates to a plant for the thermal treatment of a mineral material in the cement, lime, waste, and / or basic materials industries for processing mineral raw materials. The plant comprises at least one device for the thermal treatment of a mineral material in the cement, lime, waste, and / or basic materials industries for processing mineral raw materials. The device is configured to carry out the process according to the invention. The plant particularly preferably includes a device for generating electricity. The device for generating electricity is configured for the combustion of ammonia as the main fuel.This allows for a simple, safe, and constant supply of climate-neutral electricity using green ammonia, without requiring the space for wind or solar power and without the fluctuations of these natural resources affecting production operations. Furthermore, using a single primary fuel simplifies the processes.

[0035] The process according to the invention can be carried out, for example, with a device for the thermal treatment of a mineral material, wherein the device is a combustion unit. The thermal treatment serves in particular for the production of clinker from limestone, but also, in particular, for the production of, for example, cement-like additives (supplementary cementitious material), such as activated clays. Fuels are preferably used for the thermal treatment, since this allows the heat generation to be directly linked with the heat consumption for the thermal treatment. The combustion unit has an ammonia supply for the input of ammonia as fuel. Of the possible fuels, ammonia is particularly suitable for the cement, lime, and / or basic materials industries. This is due to a number of reasons.Firstly, the cement, lime, waste, and / or basic materials industries often operate at high temperatures (up to 2000 °C), making the formation of nitrogen oxides a significant concern. The use of ammonia allows for the intrinsic removal of these nitrogen oxides. Furthermore, clays, for example, can inherently contain ammonia, meaning that the plants are typically designed for ammonia reduction and / or combustion. Additionally, ammonia can be easily decomposed into its components, hydrogen and nitrogen, allowing for the production of at least some hydrogen, which can be used for reduction processes, particularly for color optimization. It is essential that ammonia is used as the primary fuel and not merely for NOx reduction or color optimization.The combustion device has an oxygen supply for the introduction of an oxygen-containing gas. This oxygen-containing gas can be, for example, air. It can also be a gas enriched with oxygen, for example, with 25 to 80% oxygen by volume. The device has at least one gas sensor. The gas sensor is located downstream of the combustion device. The device also includes a control device. The control device is configured to receive data from the gas sensor. Furthermore, the control device is configured to regulate the ammonia and oxygen supplies. Thus, the device is able to actively regulate the fuel (ammonia) and oxygen according to the values ​​detected by the gas sensor.This is particularly advantageous, for example, in the thermal activation of clays, since clays typically contain varying levels of ammonia or volatile hydrocarbons, thus directly influencing energy input and flame temperature. Furthermore, the combustion of ammonia is more prone to disturbances than, for example, the combustion of natural gas or hydrogen, making active control preferable for this reason as well.

[0036] Ammonia provides more than 50% of the thermal energy generated by combustion. The overall process may also require additional electrical energy, for example, for compressors, pumps, or control electronics, which is not supplied to the thermal treatment process as thermal energy. Furthermore, electric preheating or electric trace heating can introduce additional thermal energy into the process without combustion.

[0037] In a further embodiment of the invention, the gas sensor is configured as an ammonia sensor, a nitrogen oxide sensor, a temperature sensor, an oxygen sensor, and / or a carbon monoxide sensor. Preferably, several gas sensors, in particular different types of gas sensors, can be used. Using several different gas sensors makes it easier to also detect the influence of fluctuations in the mineral material and to adjust the supply of ammonia and oxygen accordingly.

[0038] In a further embodiment of the invention, the device includes an auxiliary fuel supply for an auxiliary fuel. An auxiliary fuel provides less than 25% of the thermal energy generated by combustion. This value can also be significantly lower, for example, below 5% or even below 1% of the thermal energy provided. The auxiliary fuel thus serves less as an energy carrier itself, but rather to support and stabilize the combustion of the ammonia. Ammonia tends to produce an irregular flame during combustion, which can lead to incomplete combustion.

[0039] In this embodiment, the first gas sensor is a temperature sensor. The control device is designed to regulate the auxiliary fuel supply depending on the temperature detected by the temperature sensor.

[0040] In a further embodiment of the invention, the device includes an ammonia-to-hydrogen conversion unit. In this unit, the process of ammonia synthesis proceeds in reverse. Since this is an equilibrium reaction, very high pressures are required to shift the equilibrium towards ammonia. This allows hydrogen (and nitrogen) to be readily produced from ammonia at low pressures. The control device regulates the proportion of ammonia supplied to the ammonia-to-hydrogen conversion unit. For example, the hydrogen content can be increased to improve flame stability.

[0041] In a further embodiment of the invention, the device includes a nitrogen oxide reduction device. The presence of ammonia, which is used as fuel, is advantageous in this case. The ammonia can also be used for the catalytic or, in particular, non-catalytic decomposition of nitrogen oxides. While this leads to a loss of calorific value due to synproportionation, it also simplifies exhaust gas purification. The reduction of nitrogen oxides is preferably carried out catalytically.

[0042] In particular, in a temperature range between 850 °C and 1100 °C, preferably in a temperature range between 950 °C and 1000 °C, the formation of nitrogen oxides is reduced by the non-catalytic reaction with ammonia.

[0043] Alternatively or additionally, an SCR catalyst can be provided for the selective catalytic reduction of nitrogen oxides. This preferably takes place in a temperature range between 150 °C and 650 °C, more preferably in a temperature range between 250 °C and 450 °C. This allows for an efficient reduction of the nitrogen oxide compounds formed.

[0044] Alternatively or additionally, an oxidation catalyst can be used, which is operated particularly in a temperature range between 100 °C and 650 °C, preferably in a temperature range between 250 °C and 500 °C, and is used to reduce incompletely converted ammonia, but also, for example, carbon-containing compounds released from clays.

[0045] Alternatively or additionally, a reaction to reduce incompletely reacted ammonia and / or nitrogen oxides and / or carbon-containing compounds can be carried out in a temperature range between 750 °C and 1150 °C, preferably in a temperature range between 850 °C and 950 °C, with an oxygen content of at least 2 vol% oxygen, preferably in a range between 4 vol% and 8 vol% oxygen.

[0046] In a further embodiment of the invention, oxygen and ammonia are supplied separately for combustion. This is preferably done separately, for example by separate nozzles in at least one burner, in order to achieve particularly targeted combustion.

[0047] In a further embodiment of the invention, the ammonia concentration, nitrogen oxide concentration, oxygen concentration, carbon monoxide concentration, and / or temperature are detected by at least one gas sensor. The supply of oxygen and / or ammonia to the combustion process is controlled depending on the ammonia concentration, nitrogen oxide concentration, oxygen concentration, carbon monoxide concentration, and / or temperature detected downstream of the combustion process. This makes it possible, for example, to reliably compensate for fluctuations in the process, which may be introduced by fluctuations in the mineral material, and thus prevent disruption to the less stable combustion of ammonia compared to conventional fuels such as natural gas.

[0048] Of the possible fuels, ammonia and, if necessary, gas mixtures produced from ammonia (partially cracked) are suitable for the process.

[0049] In a further embodiment of the invention, after at least partial splitting of ammonia into hydrogen and nitrogen, the hydrogen contained in the mixture can be separated from the mixture and subsequently added back in a controlled manner for the combustion of the ammonia.

[0050] In a further embodiment of the invention, the oxygen supply is regulated depending on the nitrogen oxide concentration detected downstream of the combustion gas. This is particularly preferred to enable optimal combustion of the ammonia while simultaneously ensuring that just enough ammonia remains available after combustion for denitrification. Specifically, a portion of the main fuel, ammonia, is used for the reduction of nitrogen oxides. One of the advantages of using ammonia as the main fuel is that it can also be used for the catalytic or, in particular, the non-catalytic decomposition of nitrogen oxides. While this leads to a loss of calorific value due to synproportionation, it also simplifies exhaust gas purification. The reduction of nitrogen oxides is preferably carried out catalytically.

[0051] In particular, in a temperature range between 850 °C and 1100 °C, preferably in a temperature range between 950 °C and 1000 °C, the formation of nitrogen oxides is reduced by the non-catalytic reaction with ammonia.

[0052] Alternatively or additionally, an SCR catalyst can be provided for the selective catalytic reduction of nitrogen oxides. This preferably takes place in a temperature range between 150 °C and 650 °C, more preferably in a temperature range between 250 °C and 450 °C. This allows for an efficient reduction of the nitrogen oxide compounds formed.

[0053] Alternatively or additionally, an oxidation catalyst can be used, which is operated particularly in a temperature range between 100 °C and 650 °C, preferably in a temperature range between 250 °C and 500 °C, and is used to reduce incompletely converted ammonia, but also, for example, carbon-containing compounds released from clays.

[0054] Alternatively or additionally, a reaction to reduce incompletely converted ammonia and / or nitrogen oxides and / or carbon-containing compounds can be carried out in a temperature range between 750 °C and 1150 °C, preferably in a temperature range between 850 °C and 950 °C, at an oxygen content of at least 2 vol% oxygen, preferably in a range between 4 vol% and 8 vol% oxygen. In a further embodiment of the system, the oxygen supply is controlled depending on the ammonia concentration detected downstream of the combustion process. This ensures complete combustion, particularly to avoid unwanted emissions. Furthermore, especially with enriched oxygen, excess oxygen and thus unnecessary costs and energy waste for enrichment can be avoided.

[0055] In a further embodiment of the invention, the combustion of the main fuel takes place at a first location and at a second location. The second location is arranged downstream of the first location. For example, the first location is a rotary kiln and the second location is a fluidized bed calciner located downstream of the gas stream and upstream of the material stream. The gas sensor is arranged between the first and second locations. The supply of ammonia and / or oxygen to the second location is controlled based on the values ​​detected by the gas sensor.

[0056] In further embodiments of the invention, the combustion of the main fuel ammonia, hydrogen produced from ammonia, or a mixture thereof takes place at at least one injection point of a single-stage or multi-stage thermal reactor, such as a multi-stage or shaft furnace. Preferably, at least two gas sensors are installed on different stages or at different heights within the furnace. The supply of the main fuel and / or the supply of oxygen are then controlled according to the values ​​detected by the gas sensors.

[0057] In a further embodiment of the invention, the device includes an additional gas sensor downstream of the second location. The supply of ammonia and / or oxygen to the second location is controlled depending on the values ​​detected by the gas sensor and the additional gas sensor.

[0058] In a further embodiment of the invention, the ammonia is partially converted into hydrogen and nitrogen. The conversion rate is controlled by the control device based on the parameters detected by the first gas sensor. In another embodiment of the invention, pollutant reduction occurs. The presence of ammonia, which is used as fuel, is advantageous in this case. The ammonia can also be used for the catalytic or, in particular, non-catalytic decomposition of nitrogen oxides. While this leads to a loss of calorific value due to synproportionation, it also simplifies exhaust gas purification. Preferably, the reduction of nitrogen oxides is carried out non-catalytically.

[0059] In particular, in a temperature range between 850 °C and 1100 °C, preferably in a temperature range between 950 °C and 1000 °C, the formation of nitrogen oxides is reduced by the non-catalytic reaction with ammonia.

[0060] Alternatively or additionally, an SCR catalyst can be provided for the selective catalytic reduction of nitrogen oxides. This preferably takes place in a temperature range between 150 °C and 650 °C, more preferably in a temperature range between 250 °C and 450 °C. This allows for an efficient reduction of the nitrogen oxide compounds formed.

[0061] Alternatively or additionally, an oxidation catalyst can be used, which is operated particularly in a temperature range between 100 °C and 650 °C, preferably in a temperature range between 250 °C and 500 °C, and is used to reduce incompletely converted ammonia, but also, for example, carbon-containing compounds released from clays.

[0062] Alternatively or additionally, a reaction to reduce incompletely reacted ammonia and / or nitrogen oxides and / or carbon-containing compounds can be carried out in a temperature range between 750 °C and 1150 °C, preferably in a temperature range between 850 °C and 950 °C, with an oxygen content of at least 2 vol% oxygen, preferably in a range between 4 vol% and 8 vol% oxygen.

[0063] In a further embodiment of the invention, the main fuel ammonia, hydrogen produced from ammonia, or a mixture thereof is used to produce clinker from gypsum, in particular from aorai gypsum. In this process, a portion of the main fuel can be converted from the driven-off SO3 to produce ammonium sulfate, thus buffering the corrosive properties of the SO3 load that would otherwise be generated in the process.

[0064] In a further embodiment of the invention, an additional gas sensor is provided for detecting hydrocarbons. This additional gas sensor measures the concentration of hydrocarbons. Hydrocarbons can originate, for example, from the raw clays used and must be combusted cleanly and completely to prevent unwanted emissions.

Claims

Patent claims 1. Method for the thermal treatment of a mineral material in the cement, lime, residue, and / or basic materials industry for the processing of mineral basic materials, wherein ammonia is used as the main fuel, wherein ammonia as the main fuel provides more than 50% of the thermal energy generated by combustion.

2. The method according to claim 1, characterized in that at least one auxiliary fuel is used, wherein the auxiliary fuel provides less than 25% of the thermal energy produced by combustion, wherein the auxiliary fuel is selected from the group comprising hydrogen, methane, natural gas, coal, oil, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methylpropan-2-ol, diethyl ether, 1,2-dimethoxyethane, 2-methoxy-2-methylpropane, 2-methoxy-2-methylbutane, tert-hexyl methyl ether, 2-ethoxy-2-methylpropane, 2-ethoxy-2-methylbutane, 2-[(propan-2-yl)oxy]propane, substitute fuel, in particular biomass.

3. The method according to claim 2, characterized in that the auxiliary fuel is selected from the group comprising methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methylpropan-2-ol, 2-methoxy-2-methylpropane, 2-methoxy-2-methylbutane, tert-hexyl methyl ether, 2-ethoxy-2-methylpropane, 2-ethoxy-2-methylbutane, 2-[(propan-2-yl)oxy]propane.

4. Method according to one of the preceding claims, characterized in that the ammonia is burned in a temperature range of 800 °C to 1600 °C.

5. Method according to one of the preceding claims, characterized in that the ammonia is at least partially converted into hydrogen and nitrogen.

6. The method according to claim 5, characterized in that the ammonia is converted into hydrogen and nitrogen at least to such an extent that the The hydrogen content is 20 to 80 vol%, preferably 35 to 65 vol%, particularly preferably 45 to 55 vol%.

7. A method according to one of the preceding claims, characterized in that the main fuel ammonia, hydrogen produced from ammonia or a mixture thereof is burned in a calciner and / or rotary kiln and / or multi-stage kiln and / or shaft and / or multi-shaft kiln and / or another single-stage or multi-stage thermal reactor.

8. Method according to one of the preceding claims, characterized in that a gas stream with an oxygen content of more than 20 vol.%, preferably more than 22 vol.%, further preferably 25 to 80 vol.%, further preferably 35 to 80 vol.%, particularly preferably 30 to 45 vol.%, is supplied to the main fuel.

9. Method according to one of the preceding claims, characterized in that the combustion takes place in two stages at at least two locations arranged one after the other in the gas stream, wherein the main fuel ammonia is completely supplied at the first location, wherein only a deficit of oxygen is supplied at the first location, and wherein at the second location, situated downstream of the first location in the direction of the gas stream, the oxygen is added at least stoichiometrically.

10. Method according to claim 9, characterized in that a rotary kiln is selected as the first location of combustion and a calciner as the second location.

11. Method according to one of the preceding claims, characterized in that the content of ammonia, nitrogen oxides, oxygen, carbon monoxide and / or hydrocarbons in the gas stream is detected and that the amount of oxygen supplied to the combustion is regulated according to the detected content of ammonia, nitrogen oxides, oxygen, carbon monoxide and / or hydrocarbons.

12. Method according to one of the preceding claims, characterized in that the exhaust gases are fed to a grinding and / or drying process, wherein the product of the grinding and / or drying process is thermally treated.

13. Method according to one of the preceding claims, characterized in that the main fuel is divided into at least a first partial fuel stream and a second partial fuel stream, wherein the first partial fuel stream is burned at a first location for thermal treatment, wherein the second partial fuel stream is burned at a second location for thermal treatment, wherein the second location is downstream of the first location in terms of gas flow, and wherein the combustion at the first location takes place at higher temperatures than at the second location.

14. Method according to one of the preceding claims, characterized in that the combustion of the main fuel is carried out with a swirling flame.

15. Method according to claim 14, characterized in that the length, shape and / or temperature are adjusted via the swirl and divergence of the swirl flame.

16. Method according to one of the preceding claims, characterized in that plasma-assisted start-up and / or ignition burners are used.

17. Method according to one of the preceding claims, characterized in that a portion of the main fuel ammonia is used to reduce nitrogen oxides.

18. Method according to claim 17, characterized in that the reduction of nitrogen oxides is catalytic.

19. Method according to one of the preceding claims, characterized in that, after the combustion of the main fuel ammonia, a catalytic oxidation of the ammonia takes place.

20. Method according to one of the preceding claims, characterized in that the main fuel ammonia is used at least partially for reducing color optimization before combustion.

21. Method according to one of the preceding claims, characterized in that the nitrogen oxides produced during the combustion of the main fuel are used for the production of nitric acid.

22. Method according to one of the preceding claims, characterized in that the main fuel is ammonia, hydrogen produced from ammonia or a mixture thereof for the production of clinker from gypsum, in particular from waste gypsum.

23. Plant for the thermal treatment of a mineral material in the cement, lime, residue and / or basic materials industry for the processing of mineral raw materials, wherein the plant comprises at least one device for the thermal treatment of a mineral material in the cement, lime, residue and / or basic materials industry for the processing of mineral raw materials, wherein the device is designed for carrying out the method according to one of the preceding claims.

24. Plant according to claim 23, characterized in that the plant has a device for generating electric current, wherein the device for generating electrical energy is designed for the combustion of ammonia as the main fuel.