System for manufacturing thermally activated materials

Abstract

The present invention relates to a system (10) for manufacturing a thermally activated material, wherein the system (10) comprises a thermal activation device (20); the thermal activation device (20) comprises a material cooler (24); the thermal activation device (20) comprises an oxygen enrichment gas supply unit (30); the system (10) comprises an air separation system (40); the air separation system (40) comprises an oxygen outlet (41) for oxygen enrichment gas and a nitrogen outlet (42) for nitrogen enrichment gas; and the oxygen outlet (41 The system (10) is characterized in that a nitrogen outlet (42) and a nitrogen outlet (42) are connected to an oxygen enrichment gas supply unit (30); the system (10) has combustible material processing devices (50, 55, 56) having protective gas inlets (52), and the nitrogen outlet (42) and protective gas inlets (52) are connected to each other directly or via gas heating devices, and a material cooler (24) is connected at least partially as a gas heating device.

Description

Technical Field

[0001] The present invention relates to a plant, for example for producing cement clinker, according to an oxy-fuel combustion process that safely prepares fuel without diluting an enriched carbon dioxide off-gas stream.

Background Art

[0002] Plants for heat treatment of materials, such as plants for producing cement, include a plurality of devices that are often connected to each other in complex ways. For example, such plants typically have a grinding device for fuel such as coal, but the fuel may also be an alternative fuel, for example biomass. To prevent ignition of these materials during grinding, off-gas from the actual heat treatment, in which most of the oxygen has usually been converted to carbon dioxide, is used. Furthermore, residual heat also makes this gas suitable for drying fuel, particularly in the case of water-containing fuel.

[0003] As part of efforts to reduce carbon dioxide emissions to mitigate climate change, plants are increasingly being redesigned. One essential approach is what is known as oxy-fuel combustion process. By using oxygen as pure as possible, substantially pure carbon dioxide is produced as off-gas (after removal of water), with the result that laborious separation of nitrogen is not required. To make this efficient, it is necessary to prevent other gases from secondary air sources, such as nitrogen from ambient air, from entering the off-gas.

[0004] German Patent Application Publication No. 102018206673 and German Patent Application Publication No. 102018206674 disclose such oxy-fuel combustion processes.

[0005] Japanese Patent Application Laid-open No. Sho 59-24115 discloses combustion of coal dust.

[0006] International Publication No. 94 / 24484 discloses a method for reducing emissions during incineration of waste.

[0007] U.S. Patent Application Publication No. 2014 / 238281 discloses a method for supplying pulverized fuel for a combustion device using an oxygen combustion process.

[0008] However, this means that passing such a carbon dioxide-enriched off-gas through the mill is undesirable because the unavoidable false air within the mill results in undesirable dilution of the off-gas. As a result, this protective gas can no longer be used in grinding devices, especially for grinding fuels. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] German Patent Application Publication No. 102018206673 [Patent Document 2] German Patent Application Publication No. 102018206674 [Patent Document 3] Japanese Patent Application Publication No. 59-24115 [Patent Document 4] International Publication No. 94 / 24484 [Patent Document 5] U.S. Patent Application Publication No. 2014 / 238281 [Overview of the project] [Problems that the invention aims to solve]

[0010] The objective of the present invention is to provide an atmosphere suitable for pulverizing flammable materials throughout a plant network. [Means for solving the problem]

[0011] This objective is achieved by a plant having the features described in claim 1. Advantageous developments will become apparent from the dependent claims, the following description, and the drawings.

[0012] The plant according to the present invention is used to produce thermally activated materials. Examples of such plants can be found, for example, in the cement industry, in the production of clinker from limestone, or in the thermal activation of clay. Alternatively, such plants can be found in ore processing, for example, the roasting of lithium ore. The plant has a device for thermal activation. This can have any embodiment according to the prior art, and several different embodiments are well known to those skilled in the art. The device for thermal activation has an oxygen-enriched gas supply unit. Thus, the device for thermal activation operates according to an oxygen combustion process to have carbon dioxide as pure as possible as an off-gas, which makes it possible to avoid the cumbersome carbon dioxide separation process and save investment and energy. The plant has an air fractionation device. This makes the oxygen-enriched gas stream available for oxygen combustion operation. The air fractionation plant has an oxygen outlet for oxygen-enriched gas and a nitrogen outlet for nitrogen-enriched gas. The oxygen outlet is connected to the oxygen-enriched gas supply unit. The plant also has a combustible material processing device. The combustible material may be, for example, coal or an alternative fuel such as biomass. For example, when processing flammable materials during grinding, an oxygen-deficient atmosphere is advantageous, or even necessary, especially since dust can very easily produce flammable or even explosive mixtures. For instance, a flammable material processing device prepares the necessary fuel for thermal activation. A flammable material processing device has a protective gas inlet.

[0013] According to the present invention, the nitrogen outlet and the protective gas inlet are connected to each other via a gas heating device. Therefore, as in the previous case, the gas depleted by combustion within the device for thermal activation within the combustible material processing device is no longer used, and this carbon dioxide-containing gas is not diluted by secondary air within the combustible material processing device. Instead, a nitrogen-enriched gas stream from an air fractionation plant is used. For this purpose, the nitrogen-enriched gas stream from the air fractionation plant in this invention passes through a gas heating device and is preheated.

[0014] According to the present invention, the device for thermal activation includes a material cooler. The material cooler is at least partially connected as a gas heating device, i.e., positioned between the nitrogen outlet and the protective gas inlet. Partial connection is preferred, and in particular the material cooler is divided into three zones. The first zone is the hottest, and this is where the high-temperature material is placed. In this first zone, cooling is performed using the oxygen-enriched gas to preheat the oxygen-enriched gas to the maximum extent for heat treatment and thus retain as much heat as possible in the process. The second zone is connected to the nitrogen outlet and used to preheat the nitrogen-enriched gas. This utilizes this low calorific energy, which is warm enough to further dry the material. In the last, coldest third zone, final cooling is performed, for example, by ambient air.

[0015] In further embodiments of the present invention, the processing device for combustible materials is a grinding device and / or a drying device. The processing device here may be, for example, a simple mill for producing charcoal dust. The processing device may be a grinding or crushing device with a subsequent air dryer, i.e., a combination of a grinding device and a drying device. This is advantageous, for example, for wood as an alternative fuel. Alternatively, it may be a pure drying device, for example, to thoroughly dehydrate the biomass first. Two processing devices may be provided, one as a pure drying device and the other as a combination of a grinding device and a drying device.

[0016] In a further embodiment of the present invention, the device for thermal activation has an off-gas outlet. The off-gas outlet may for example be arranged downstream of the preheater. This is the location where the gas stream exits the device for thermal activation. The off-gas outlet is connected to a heat exchanger. The heat exchanger is connected as a gas heating device. This means that the heat exchanger has, on one side, a first inlet connected to the off-gas outlet. The outlet on the first side may for example be connected to a carbon dioxide liquefaction plant. The other side is for an endothermic gas, specifically a nitrogen-enriched gas, and accordingly, 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 recuperative heat exchanger or a regenerative heat exchanger. Particularly preferably, the heat exchanger is a rotary heat exchanger.

[0017] In a further embodiment of the present invention, the air fractionation plant is a cryogenic air fractionation plant. Although air fractionation by membrane processes or pressure swing adsorption is also conceivable, cryogenic air fractionation is still advantageous for the required amount of oxygen and the desired purity.

[0018] Hereinafter, the plant according to the present invention will be described in more detail based on exemplary embodiments shown in the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] [Figure 1] It shows a first example according to the present invention. [Figure 2] It shows an alternative second example. MODE FOR CARRYING OUT THE INVENTION

[0020] Figure 1 shows a first example of a plant 10 according to the present invention. The plant comprises a device 20 for thermal activation. The device 20 for thermal activation has a material supply 28 supplied with, for example, limestone. The supplied material is preheated in a preheater 21, calcined in a calcination furnace 22, and fired in a rotary kiln 23. The product is cooled in a material cooler 24 and discharged via a product take-out unit.

[0021] One device 20 for thermal activation is operated according to an oxy-fuel combustion process, i.e., preferably with the highest possible oxygen content, in order to ultimately obtain the highest possible carbon dioxide content. For this purpose, the plant comprises an air fractionation plant 40, from which an oxygen-enriched gas having, for example, more than 95% by volume of oxygen is supplied from an oxygen outlet 41 to an oxygen-enriched gas supply 30, in this case to a first zone 25 of a material cooler 24. Therein, the oxygen-enriched gas is preheated and then transferred into the rotary kiln 23. The gas exiting the preheater 21 is transferred to a carbon dioxide liquefaction plant 60 via an off-gas outlet 61.

[0022] The nitrogen-enriched gas stream is supplied via a nitrogen outlet 42 to a second zone 26 of the material cooler 24, where it is preheated. The preheated nitrogen-enriched gas stream is supplied via a protective gas inlet 52 to a first combustible material treatment device 50, for example a mill connected to a flash dryer. Fuel is supplied via a fuel supply 51, crushed, dried, and then supplied, for example, to the calcination furnace 22.

[0023] Figure 2 shows an alternative plant 10 of a second example. The device 20 for thermal activation corresponds here to the first example. The oxygen-enriched gas is supplied directly to the rotary kiln 23 without preheating via the oxygen-enriched gas supply 30. The off-gas is first supplied from the preheater 21 to a heat exchanger 70 via the off-gas outlet 61, and then enters the carbon dioxide liquefaction plant 60. The nitrogen-containing gas stream enters the heat exchanger 70 from the nitrogen outlet 42 and is heated therein. For the use of high-water-content fuel, the plant 10 comprises 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 have a protective gas inlet 52, and are supplied with the nitrogen-containing gas heated by the preheater 70. Description of Reference Signs

[0024] 10. Plant for manufacturing thermally activated materials 20 Devices for thermal activation 21 Preheater 22 kilns 23 Rotary Kiln 24 Material cooler 25 Zone 1 26. Zone 2 27. The Third Zone 28 Material supply section 29 Product Dispensing Section 30. Oxygen-enriched gas supply unit 40 Air fractionation plant 41 Oxygen outlet 42 Nitrogen outlet 50. First processing device for flammable materials 51 Fuel supply section 52 Protective gas inlet 55. Second processing device for flammable materials 56. Third processing device for flammable materials 60 Carbon Dioxide Liquefaction Plant 61 Off-gas outlet 70 Heat exchanger

Claims

1. A plant (10) for manufacturing a thermally activated material, wherein the plant (10) has a thermal activation device (20), the thermal activation device (20) has a material cooler (24), the thermal activation device (20) has an oxygen enrichment gas supply unit (30), the plant (10) has an air fractionation plant (40), the air fractionation plant (40) has an oxygen outlet (41) for oxygen enrichment gas and a nitrogen outlet (42) for nitrogen enrichment gas, The plant (10) is characterized in that the oxygen outlet (41) is connected to the oxygen enrichment gas supply unit (30), the plant (10) has combustible material processing devices (50, 55, 56), the combustible material processing devices (50, 55, 56) have a protective gas inlet (52), the nitrogen outlet (42) and the protective gas inlet (52) are connected to each other via a gas heating device, and the material cooler (24) is at least partially connected as a gas heating device.

2. The plant (10) according to claim 1, characterized in that the processing devices for the combustible material (50, 55, 56) are a crushing device and / or a drying device.

3. The plant (10) according to claim 1 or 2, characterized in that the thermal activation device (20) has an off-gas outlet (61), the off-gas outlet (61) is connected to a heat exchanger (70), and the heat exchanger (70) is connected as a gas heating device.

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

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

6. The plant (10) according to any one of claims 1 to 5, characterized in that the air fractionation plant (40) is a cryogenic air fractionation plant (40).

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