System for producing thermally activated materials

Abstract

The invention relates to a device (10) for producing a thermally activated material, the device (10) comprising a thermal activation device (20) having a material cooler (24), the thermal activation device (20) having an oxygen-enriched gas feed opening (30), the device (10) having an air separation device (40), the air separation device (40) having an oxygen-enriched gas feed opening (30), the invention relates to a device (10) for separating gas from oxygen, comprising an air separation device (40) having an oxygen outlet (41) for oxygen-enriched gas and a nitrogen outlet (42) for nitrogen-enriched gas, said oxygen outlet (41) being connected to said oxygen-enriched gas feed port (30), said device (10) having a combustible substance treatment device (50, 55, 56) having a protective gas inlet (52), characterized in that the protective gas inlet (52) is connected to the air separation device (40). The nitrogen outlet (42) and the protective gas inlet (52) are connected directly or to each other by means of a gas heating device, wherein the material cooler (24) is at least partially connected as the gas heating device.

Description

[0001] The present invention relates to an apparatus, for example an apparatus for producing cement clinker according to an oxygen-enriched fuel process, which can ensure that the carbon dioxide-rich exhaust gas stream is not diluted while preparing fuel.

[0002] In equipment used for the heat treatment of materials, such as cement production plants, there are many devices that are often interconnected in a complex manner. For example, such equipment is typically equipped with grinding equipment for both fuels (such as coal) and alternative fuels (such as biomass). To prevent these materials from igniting during the grinding process, waste gases generated during the actual heat treatment process are usually utilized, where most of the oxygen has been converted into carbon dioxide. Furthermore, the residual heat of the waste gases also makes them suitable for dry fuels, especially when processing wet fuels.

[0003] As part of reducing carbon dioxide emissions to mitigate climate change, factories are increasingly being redesigned and retrofitted. A key approach is the so-called oxy-fuel process. Using the purest possible oxygen produces nearly pure carbon dioxide as exhaust gas (after removing water), thus eliminating the need for laborious nitrogen separation from the exhaust. For efficient operation, it is essential to prevent other gases from secondary air sources, such as nitrogen from ambient air, from contaminating the exhaust.

[0004] DE 10 2018 206 673 A1 and DE 10 2018 206 674 A1 disclose such oxygen-enriched combustion processes.

[0005] JP S59 24115 A discloses the combustion of pulverized coal.

[0006] WO 94 / 24484 A1 discloses a method for reducing emissions during waste incineration.

[0007] US 2014 / 238281 A1 discloses a method for supplying powdered fuel to a combustion device for an oxygen-enriched combustion process.

[0008] However, this means that introducing such carbon dioxide-rich exhaust gases into a grinding mill is disadvantageous, as unavoidable air leakage within the mill leads to unintended dilution of the exhaust gases. This, in turn, renders this protective gas unsuitable for grinding equipment, particularly for grinding fuels.

[0009] The purpose of this invention is to provide a gaseous environment suitable for grinding combustible materials throughout the entire device network.

[0010] This objective is achieved by a device having the features described in claim 1. Advantageous improvements will be apparent from the dependent claims, the following description, and the accompanying drawings.

[0011] The apparatus according to the invention is used for producing thermally activated materials. Examples of such apparatus can be found in the cement industry, such as the thermal activation of clinker or clay produced from limestone. Alternatively, such apparatus can also be found in ore processing, such as the roasting of lithium ore. The apparatus has a thermal activation device. The apparatus can have any embodiment according to the prior art, and many different embodiments are well known to those skilled in the art. The thermal activation device has an inlet for oxygen-enriched gas. Therefore, the thermal activation device operates according to an oxy-fuel combustion process to obtain carbon dioxide as pure as possible as possible as exhaust gas, which eliminates the need for a complex carbon dioxide separation process, thereby saving investment and energy. The apparatus has an air separation device. The air separation device provides an oxygen-enriched flow for oxy-fuel combustion operation. The air separation device has an oxygen outlet for oxygen-enriched gas and a nitrogen outlet for nitrogen-enriched gas. The oxygen outlet is connected to the inlet for oxygen-enriched gas. The apparatus also has a combustible material treatment device. The combustible material can be, for example, coal, or alternative fuels such as biomass. When treating combustible materials, such as during grinding, dust is particularly prone to forming flammable or even explosive mixtures, so an oxygen-deficient environment is advantageous or even necessary. For example, the combustible material processing equipment is responsible for preparing the fuel required for the thermal activation equipment. The combustible material processing equipment has a protective gas inlet.

[0012] According to the present invention, the nitrogen outlet and the protective gas inlet are interconnected via a gas heating device. Therefore, unlike conventional methods, the gas consumed by combustion in the thermal activation device is no longer used in the combustible material processing equipment, thus avoiding dilution of the carbon dioxide-containing gas by secondary air in the combustible material processing equipment. Instead, a nitrogen-rich gas stream from the air separation unit is used. For this purpose, the nitrogen-rich gas stream from the air separation unit is preheated by the gas heating device.

[0013] According to the invention, the thermal activation equipment includes a material cooler. The material cooler at least partially functions as the gas heating device, i.e., it is arranged between the nitrogen outlet and the protective gas inlet. Preferably, it partially functions as such; specifically, the material cooler is divided into three zones. The first zone has the highest temperature, and hot material enters this zone. In this first zone, the cooling process uses oxygen-enriched gas to preheat the gas to the maximum extent possible for heat treatment, thereby retaining as much heat as possible during the process. The second zone is connected to the nitrogen outlet for preheating the nitrogen-enriched gas. This utilizes the energy of this portion with a low calorific value, while its temperature is sufficient to dry the material. Final cooling is performed in the last and coldest third zone, for example, using ambient air.

[0014] In a further embodiment of the invention, the equipment for processing combustible materials is a grinding and / or drying device. The processing equipment can be a simple mill, for example, for producing pulverized coal. The processing equipment can be a grinding or crushing device with a subsequent flash dryer, i.e., a combination of grinding and drying equipment. This is advantageous for alternative fuels such as wood. Alternatively, it can be a purely drying device, for example, for initially and sufficiently removing moisture from biomass. Two processing devices can also be provided, one as a purely drying device and the other as a combination of grinding and drying.

[0015] In a further embodiment of the invention, the thermal activation device has an exhaust gas outlet. The exhaust gas outlet may, for example, be located downstream of a preheater. This point is where the gas flow exits the thermal activation device. The exhaust gas outlet is connected to a heat exchanger. The heat exchanger is connected as a gas heating device. This means that one side of the heat exchanger has a first inlet connected to the exhaust gas outlet. The outlet on the first side may, for example, be connected to a carbon dioxide liquefaction device. The other side is used for heat-absorbing gas, specifically nitrogen-rich gas, therefore the inlet on the second side is connected to a nitrogen outlet, and the outlet on the second side is connected to a protective gas inlet. Preferably, the heat exchanger is a recovery heat exchanger or a regenerative heat exchanger. Particularly preferably, the heat exchanger is a rotary heat exchanger.

[0016] In a further embodiment of the invention, the air separation device is a cryogenic air separation device. Although air separation based on membrane separation or pressure swing adsorption is also conceivable, cryogenic air separation currently remains advantageous for the required oxygen quantity and desired purity.

[0017] The apparatus according to the present invention will now be described in more detail based on exemplary embodiments shown in the accompanying drawings.

[0018] Figure 1 According to a first example of the present invention.

[0019] Figure 2 Second alternative example.

[0020] Figure 1 A first example of an apparatus 10 according to the invention is shown. The apparatus includes a thermal activation device 20. The thermal activation device 20 has, for example, a material inlet 28 through which, for example, limestone is added. The added material is preheated in a preheater 21, calcined in a decomposition furnace 22, and burned in a rotary kiln 23. The product is cooled in a material cooler 24 and discharged through a product outlet.

[0021] The thermal activation equipment 20 operates according to an oxygen-enriched combustion process, preferably using the highest possible oxygen content to ultimately obtain the highest possible carbon dioxide content. For this purpose, the device is equipped with an air separator 40. Oxygen-enriched gas, for example, with an oxygen content exceeding 95% by volume, is conveyed from the oxygen outlet 41 to the oxygen-enriched gas inlet 30, which in this example is the first zone 25 of the material cooler 24. Here, the oxygen-enriched gas is preheated and then fed into the rotary kiln 23. The gas discharged from the preheater 21 is conveyed through the exhaust outlet 61 to the carbon dioxide liquefaction unit 60.

[0022] The nitrogen-rich gas stream is conveyed via nitrogen outlet 42 to the second zone 26 of the material cooler 24, where it is preheated. The preheated nitrogen-rich gas stream is then conveyed via protective gas inlet 52 to the first combustible material processing unit 50, such as a mill connected to a flash dryer. Fuel is added via fuel inlet 51, pulverized, dried, and then fed, for example, into the decomposition furnace 22.

[0023] Figure 2 A second example of the alternative device 10 is shown. The thermal activation device 20 here is the same as in the first example. Oxygen-enriched gas is fed directly into the rotary kiln 23 without preheating via the oxygen-enriched gas inlet 30. Exhaust gas is first conveyed from the preheater 21 to the heat exchanger 70 via the exhaust gas outlet 61, and then enters the carbon dioxide liquefaction unit 60. The nitrogen-containing gas stream enters the heat exchanger 70 from the nitrogen outlet 42 and is heated there. For the use of very wet fuel, the device 10 is equipped with a second combustible material treatment device 55 (in the form of a dryer) and a third combustible material treatment device 56 (in the form of a mill). Both the second combustible material treatment device 55 and the third combustible material treatment device 56 are provided with a protective gas inlet 52 and are supplied with nitrogen-containing gas heated in the preheater 70.

[0024] List of reference numerals 10. Apparatus for producing thermally activated materials 20 Thermal activation equipment 21 Preheater 22 Decomposition Furnace 23 Rotary Kiln 24 Material Cooler 25 First District 26 Second Region 27 Third Region 28 Material inlet 29 Product Exports 30 Oxygen-enriched gas inlet 40 Air Separation Device 41 Oxygen outlet 42 Nitrogen outlet 50 First combustible material processing equipment 51 Fuel Inlet 52 Protective gas inlet 55 Second combustible material processing equipment 56 Third Combustible Material Processing Equipment 60 Carbon dioxide liquefaction unit 61 Exhaust Gas Outlet 70 Heat Exchanger

Claims

1. An apparatus (10) for producing thermally activated materials, wherein the apparatus (10) comprises a thermal activation device (20) having a material cooler (24), the thermal activation device (20) having an oxygen-enriched gas inlet (30), the apparatus (10) having an air separation device (40) having an oxygen outlet (41) for oxygen-enriched gas and a nitrogen outlet (42) for nitrogen-enriched gas, the oxygen outlet (41) being connected to the oxygen-enriched gas inlet (30), the apparatus (10) having a combustible material processing device (50, 55, 56) having a protective gas inlet (52), characterized in that, The nitrogen outlet (42) and the protective gas inlet (52) are interconnected via a gas heating device, wherein the material cooler (24) is connected at least in part as the gas heating device.

2. The apparatus (10) according to claim 1, characterized in that, The combustible material processing equipment (50, 55, 56) is a grinding equipment and / or a drying equipment.

3. The apparatus (10) according to any of the preceding claims, characterized in that, The thermal activation device (20) has an exhaust gas outlet (61), wherein the exhaust gas outlet (61) is connected to a heat exchanger (70), and the heat exchanger (70) is connected as a gas heating device.

4. The apparatus (10) according to claim 3, characterized in that, The heat exchanger (70) is a recovery heat exchanger (70) or a regenerative heat exchanger (70).

5. The apparatus (10) according to claim 3, characterized in that, The heat exchanger (70) is a rotary heat exchanger.

6. The apparatus (10) according to any of the preceding claims, characterized in that, The air separation device (40) is a low-temperature air separation device (40).

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