Cement production system based on an external thermal decomposition furnace

Abstract

The embodiment of the present application discloses a cement production system based on an external heating decomposing furnace, which comprises a preheater, a decomposer, a sintering device and a carbon collector. The preheater is provided with a first feeding port and a first discharging port. The first feeding port is used for receiving cement raw materials, and the first discharging port is used for discharging the cement raw materials preheated by the preheater. The decomposer is communicated with the first discharging port to receive the preheated cement raw materials discharged from the preheater and can heat and decompose calcium carbonate in the cement raw materials into semi-clinker and carbon dioxide gas. The decomposer is vertically arranged. The sintering device is communicated with the decomposer to receive the semi-clinker discharged from the decomposer and can sinter the semi-clinker into clinker. The carbon collector is communicated with the decomposer to receive the carbon dioxide gas discharged from the decomposer and can collect and recover the carbon dioxide gas. The cement production system based on the external heating decomposing furnace of the embodiment of the present application realizes the pure collection of the discharged CO2 by vertically arranging the decomposer.

Description

Technical Field

[0001] This invention relates to the field of cement production technology, and more specifically to a cement production system based on an external thermal decomposition furnace. Background Technology

[0002] Cement production is one of the major sources of global carbon emissions, which mainly come from "process emissions" from limestone decomposition and "energy emissions" from fuel combustion.

[0003] While there are various precalciner designs in related technologies, such as cyclone and jet furnaces, these are all internally heated reactors and cannot solve the fundamental problem of CO2 dilution. Although externally heated rotary kilns can achieve gas-solid separation, they have problems such as large equipment size, large footprint, and relatively low heat transfer efficiency. In particular, for large-scale cement production, the length of traditional externally heated rotary kilns can reach tens of meters, resulting in high investment costs and difficulties in modifying existing production lines. Summary of the Invention

[0004] The present invention aims to at least partially solve one of the technical problems in the related art.

[0005] Therefore, embodiments of the present invention propose a cement production system based on an external thermal decomposition furnace. This system, through vertically arranged decomposers, achieves pure collection of emitted CO2, with a concentration exceeding 90%, thereby reducing subsequent carbon capture energy consumption and costs by more than 60% compared to traditional technologies.

[0006] The cement production system based on an external thermal decomposition furnace according to an embodiment of the present invention includes a preheater, a decomposer, a calciner, and a carbon trap. The preheater has a first inlet and a first outlet. The first inlet is used to receive cement raw meal, and the first outlet is used to discharge the cement raw meal preheated by the preheater. The decomposer is connected to the first outlet to receive the preheated cement raw meal discharged from the preheater and can heat and decompose the calcium carbonate in the cement raw meal into semi-clinker and carbon dioxide gas. The decomposer is arranged vertically. The calciner is connected to the decomposer to receive the semi-clinker discharged from the decomposer and can sinter the semi-clinker into clinker. The carbon trap is connected to the decomposer to receive the carbon dioxide gas discharged from the decomposer and can capture and recover the carbon dioxide gas.

[0007] In the cement production system based on an external thermal decomposition furnace according to this invention, cement raw meal enters the system through the first feed port of the preheater, is preheated in the preheater, and then discharged through the first discharge port. The preheated cement raw meal enters the decomposer, which is arranged vertically. The decomposer heats and decomposes the calcium carbonate in the cement raw meal into semi-clinker and carbon dioxide gas. The carbon dioxide gas generated by the decomposer enters the carbon trap for collection and recovery. The semi-clinker discharged from the decomposer enters the sintering unit and is sintered into clinker in the sintering unit.

[0008] Compared to related technologies, the vertical arrangement of the decomposer achieves pure CO2 collection with a concentration exceeding 90%, reducing subsequent carbon capture energy consumption and costs by more than 60% compared to traditional technologies. The vertical decomposer design, combined with the direct connection to the carbon capture unit, ensures efficient capture and recovery of generated carbon dioxide, reducing carbon emissions. Compared to traditional externally heated rotary kilns, this system, with its vertically arranged decomposer, is more compact, requires less floor space, has lower investment costs, and is easier to retrofit into existing production lines.

[0009] In some embodiments, the decomposer of the cement production system based on an externally heated decomposition furnace of the present invention includes a decomposition furnace and a heating element. The decomposition furnace is used to receive preheated cement raw meal discharged from the preheater, and the heating element is disposed on the outer wall of the decomposition furnace for heating and decomposing calcium carbonate in the cement raw meal into semi-clinker and carbon dioxide gas.

[0010] In some embodiments, the cement production system based on an externally heated decomposition furnace of the present invention further includes a first connecting pipe and a second connecting pipe. The first connecting pipe is connected between the decomposition furnace and the carbon trap to introduce carbon dioxide gas into the carbon trap. One end of the second connecting pipe is connected to the first connecting pipe, and the other end of the second connecting pipe is connected to the decomposer to circulate a portion of the carbon dioxide gas in the first connecting pipe into the decomposer.

[0011] In some embodiments, the second connecting pipe of the cement production system based on an external thermal decomposition furnace of the present invention has a first air inlet for supplementing carbon dioxide gas into the decomposer.

[0012] In some embodiments, the calciner of the cement production system based on an external thermal decomposition furnace of the present invention includes a rotary kiln connected to the decomposition furnace to receive semi-clinker discharged from the decomposition furnace and sinter it into clinker.

[0013] In some embodiments, the calciner of the cement production system based on an external thermocooker according to the present invention further includes a grate cooler, which is connected to the rotary kiln for receiving and cooling clinker discharged from the rotary kiln.

[0014] In some embodiments, the cement production system based on an external thermal decomposition furnace of the present invention further includes a third connecting pipe, which is connected between the grate cooler and the decomposer, for introducing hot air heated by high-temperature clinker in the grate cooler into the decomposer.

[0015] In some embodiments, the preheater of the cement production system based on an external thermal decomposition furnace of the present invention has a second air inlet, and the decomposer has a first air outlet, the first air outlet being connected to the second air inlet for introducing hot flue gas generated in the decomposer into the preheater.

[0016] In some embodiments, the decomposer of the cement production system based on an externally heated decomposition furnace of the present invention has a second feed inlet for introducing fuel into the decomposer.

[0017] In some embodiments, the external heat source of the decomposer in the cement production system based on an externally heated decomposition furnace of the present invention may be either pulverized coal or natural gas. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a cement production system based on an external thermal decomposition furnace according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the first discharge port of a cement production system based on an external thermochemical furnace.

[0020] Reference numerals in the attached drawings: 1. Preheater; 101. First feed inlet; 102. First discharge outlet; 103. Second air inlet; 2. Decomposer; 201. Decomposition furnace; 202. Heating element; 203. First air outlet; 204. Second feed inlet; 3. Sintering device; 301. Rotary kiln; 302. Grate cooler; 4. Carbon collector; 5. First connecting pipe; 6. Second connecting pipe; 601. First air inlet; 7. Third connecting pipe. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] Reference Figures 1-2As shown, the cement production system based on an externally heated decomposition furnace 201 in this embodiment of the invention includes a preheater 1, a decomposer 2, a calciner 3, and a carbon trap 4. The preheater 1 has a first inlet 101 and a first outlet 102. The first inlet 101 is used to receive cement raw meal, and the first outlet 102 is used to discharge the cement raw meal preheated by the preheater 1. The decomposer 2 is connected to the first outlet 102 to receive the preheated cement raw meal discharged from the preheater 1 and can heat and decompose the calcium carbonate in the cement raw meal into semi-clinker and carbon dioxide gas. The decomposer 2 is arranged vertically. The calciner 3 is connected to the decomposer 2 to receive the semi-clinker discharged from the decomposer 2 and can sinter the semi-clinker into clinker. The carbon trap 4 is connected to the decomposer 2 to receive the carbon dioxide gas discharged from the decomposer 2 and can capture and recover the carbon dioxide gas.

[0023] In the cement production system based on the external thermal decomposition furnace 201 of this invention, cement raw materials enter the system through the first feed port 101 of the preheater 1, are preheated in the preheater 1, and then discharged through the first discharge port 102. The preheated cement raw materials enter the decomposer 2, which is arranged vertically. The calcium carbonate in the cement raw materials is heated and decomposed into semi-clinker and carbon dioxide gas. The carbon dioxide gas generated by the decomposer 2 enters the carbon trap 4 for collection and recovery. The semi-clinker discharged from the decomposer 2 enters the sintering unit 3 and is sintered into clinker in the sintering unit 3.

[0024] Compared to related technologies, the vertical arrangement of the decomposer 2 achieves pure collection of emitted CO2, with a concentration exceeding 90%, reducing subsequent carbon capture energy consumption and costs by more than 60% compared to traditional technologies. The vertical arrangement of the decomposer 2, combined with the direct connection to the carbon capture device 4, ensures efficient capture and recovery of the generated carbon dioxide gas, reducing carbon emissions. Compared to the traditional externally heated rotary kiln 301, this system, with its vertically arranged decomposer 2, is more compact, occupies less space, has lower investment costs, and is easier to retrofit into existing production lines.

[0025] Optionally, the decomposition furnace 201 is a vertically arranged cylinder, divided into an internal decomposition zone and an external heating zone. The internal decomposition zone is a closed material fluidization channel, and the external heating zone is equipped with a heating heat source and is physically isolated from the internal decomposition zone.

[0026] In some embodiments, such as Figures 1-2 As shown, the decomposer 2 of the cement production system based on the external heating decomposition furnace 201 in this embodiment of the invention includes a decomposition furnace 201 and a heating element 202. The decomposition furnace 201 is used to receive preheated cement raw meal discharged from the preheater 1. The heating element 202 is disposed on the outer wall of the decomposition furnace 201 to heat and decompose the calcium carbonate in the cement raw meal into semi-clinker and carbon dioxide gas.

[0027] The decomposition furnace 201 receives preheated cement raw meal discharged from the preheater 1 through its feed inlet. The preheated raw meal has an increased temperature, providing initial conditions for the subsequent decomposition reaction. The heating element 202 is located on the outer wall of the decomposition furnace 201, unlike traditional internally heated reactors where fuel and material are mixed together. The heating element 202 can use pulverized coal or natural gas as a heat source, indirectly heating the material inside the furnace through the furnace wall. Under the heat provided by the heating element 202, the calcium carbonate in the cement raw meal within the decomposition furnace 201 is heated and decomposed. The raw meal is rapidly and uniformly heated to 850-950℃, and the calcium carbonate in the raw meal decomposes rapidly within minutes, with a decomposition rate exceeding 95%.

[0028] In some embodiments, such as Figures 1-2 As shown, the cement production system based on the externally heated decomposition furnace 201 in this embodiment of the invention further includes a first connecting pipe 5 and a second connecting pipe 6. The first connecting pipe 5 is connected between the decomposition furnace 201 and the carbon trap 4 to allow carbon dioxide gas to be introduced into the carbon trap 4. One end of the second connecting pipe 6 is connected to the first connecting pipe 5, and the other end of the second connecting pipe 6 is connected to the decomposer 2 to circulate a portion of the carbon dioxide gas in the first connecting pipe 5 into the decomposer 2.

[0029] The first connecting pipe 5 is directly connected to the decomposition furnace 201 and the carbon trap 4, and is used to transport the carbon dioxide gas generated in the decomposition furnace 201 to the carbon trap 4 for collection. One end of the second connecting pipe 6 is connected to the first connecting pipe 5, and the other end is connected back to the decomposer 2, forming a gas circulation loop. Through this loop, some of the carbon dioxide gas in the first connecting pipe 5 can be transported back into the decomposer 2.

[0030] High-concentration carbon dioxide is directly transported to the carbon trap 4 via the first connecting pipe 5, avoiding the problem of CO2 dilution in traditional systems and significantly improving the efficiency and economy of carbon capture. Recycling some of the carbon dioxide back into the decomposer 2 helps maintain a stable gas environment within the decomposer 2, optimizes the conditions for the calcium carbonate decomposition reaction, and improves reaction efficiency.

[0031] In some embodiments, such as Figures 1-2 As shown, the second connecting pipe 6 of the cement production system based on the external thermal decomposition furnace 201 in this embodiment of the invention has a first air inlet 601 for supplementing and supplying carbon dioxide gas into the decomposer 2. During the initial operation of the system, due to the very low internal CO2 concentration and insufficient CO2 generated from the decomposition of raw materials for uniform fluidization, CO2 circulation has not yet been established. At this time, a certain amount of CO2 needs to be supplemented into the system from the first air inlet 601 until sufficient gas circulation and system pressure are established. Simultaneously, after the system reaches a stable state, gas leakage may occur; to maintain system stability, this loss can be compensated from the first air inlet 601.

[0032] In some embodiments, such as Figures 1-2 As shown, the calciner 3 of the cement production system based on the externally heated decomposition furnace 201 in this embodiment of the invention includes a rotary kiln 301. The rotary kiln 301 is connected to the decomposition furnace 2 to receive the semi-clinker discharged from the decomposition furnace 2 and sinter it into clinker. The rotary kiln 301 is directly connected to the decomposition furnace 2, forming a continuous production process from preheating, decomposition to calcination, reducing material transfer links and improving production efficiency.

[0033] In some embodiments, the calciner 3 of the cement production system based on the external thermocooker 201 of this invention further includes a grate cooler 302, which is connected to the rotary kiln 301 to receive and cool the clinker discharged from the rotary kiln 301. The direct connection between the grate cooler 302 and the rotary kiln 301 enables a continuous production process from clinker calcination to cooling, improving overall production efficiency.

[0034] In some embodiments, such as Figures 1-2 As shown, the cement production system based on the external thermal decomposition furnace 201 in this embodiment of the invention also includes a third connecting pipe 7, which connects the grate cooler 302 and the decomposer 2, for introducing hot air heated by the high-temperature clinker in the grate cooler 302 into the decomposer 2. The high-temperature clinker in the grate cooler 302 is rapidly cooled by the cold air, and the temperature of the cold air after heating can reach 800-1200 ℃. This portion of hot air is sent from the third connecting pipe 7 to the external heating element 202 of the decomposition furnace 201 to assist in the combustion of fuel in the heating zone.

[0035] In some embodiments, such as Figures 1-2 As shown, in this embodiment of the cement production system based on an external thermal decomposition furnace 201, the preheater 1 has a second air inlet 103, and the decomposer 2 has a first air outlet 203. The first air outlet 203 is connected to the second air inlet 103 to allow the hot flue gas generated in the decomposer 2 to be introduced into the preheater 1. The hot flue gas generated by combustion in the heating element 202 of the decomposer 2 is extracted from the first air outlet 203 and sent into the preheater 1. The flue gas moves from bottom to top and exchanges heat with the raw material in a countercurrent manner, so that the temperature of the raw material at the outlet of the preheater 1 reaches about 800°C.

[0036] In some embodiments, such as Figures 1-2 As shown, the decomposer 2 of the cement production system based on the externally heated decomposition furnace 201 in this embodiment of the invention has a second feed inlet 204, which is used to introduce fuel into the decomposer 2. This method facilitates heating the decomposer 2 with fuel.

[0037] In some embodiments, such as Figures 1-2As shown, in this embodiment of the invention, the external heat source of the decomposer 2 in the cement production system based on the externally heated decomposition furnace 201 can be either pulverized coal or natural gas. Multiple fuel options reduce the risk of interruption of a single fuel supply and enhance the continuity and stability of production.

[0038] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0039] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0042] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0043] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A cement production system based on an external thermal decomposition furnace, characterized in that, include: A preheater (1) has a first inlet (101) and a first outlet (102), the first inlet (101) being used to receive cement raw meal, and the first outlet (102) being used to discharge cement raw meal preheated by the preheater (1); Decomposer (2), which is connected to the first discharge port (102) to receive preheated cement raw meal discharged from the preheater (1) and can heat and decompose calcium carbonate in the cement raw meal into semi-clinker and carbon dioxide gas, wherein the decomposer (2) is arranged vertically. A sintering device (3) is connected to the decomposer (2) to receive the semi-cooked material discharged from the decomposer (2) and to sinter the semi-cooked material into cooked material. A carbon trap (4) is connected to the decomposer (2) to receive carbon dioxide gas emitted from the decomposer (2) and to capture and recover the carbon dioxide gas.

2. The cement production system based on an external pyrolysis furnace according to claim 1, characterized in that, The decomposer (2) includes a decomposition furnace (201) and a heating element (202). The decomposition furnace (201) is used to receive preheated cement raw materials discharged from the preheater (1). The heating element (202) is disposed on the outer wall of the decomposition furnace (201) to heat and decompose calcium carbonate in the cement raw materials into semi-clinker and carbon dioxide gas.

3. The cement production system based on an external pyrolysis furnace according to claim 1, characterized in that, Also includes: The first connecting pipe (5) is connected between the decomposition furnace (201) and the carbon trap (4) to introduce carbon dioxide gas into the carbon trap (4). The second connecting pipe (6) has one end connected to the first connecting pipe (5) and the other end connected to the decomposer (2) to circulate some of the carbon dioxide gas in the first connecting pipe (5) into the decomposer (2).

4. The cement production system based on an external pyrolysis furnace according to claim 3, characterized in that, The second connecting pipe (6) has a first air inlet (601) for supplying carbon dioxide gas into the decomposer (2).

5. The cement production system based on an external pyrolysis furnace according to claim 1, characterized in that, The sintering unit (3) includes a rotary kiln (301) connected to the decomposer (2) to receive the semi-cooked material discharged from the decomposer (2) and sinter it into cooked material.

6. The cement production system based on an external pyrolysis furnace according to claim 5, characterized in that, The sintering device (3) also includes a grate cooler (302) connected to the rotary kiln (301) for receiving and cooling the clinker discharged from the rotary kiln (301).

7. The cement production system based on an external pyrolysis furnace according to claim 6, characterized in that, It also includes a third connecting pipe (7), which is connected between the grate cooler (302) and the decomposer (2) for introducing hot air heated by high-temperature clinker in the grate cooler (302) into the decomposer (2).

8. The cement production system based on an external pyrolysis furnace according to claim 1, characterized in that, The preheater (1) has a second air inlet (103), and the decomposer (2) has a first air outlet (203), which is connected to the second air inlet (103) for introducing hot flue gas generated in the decomposer (2) into the preheater (1).

9. The cement production system based on an external pyrolysis furnace according to claim 1, characterized in that, The decomposer (2) has a second inlet (204) for feeding fuel into the decomposer (2).

10. The cement production system based on an external pyrolysis furnace according to any one of claims 1-9, characterized in that, The external heat source of the decomposer (2) can be either pulverized coal or natural gas.

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