A decomposition furnace for cement production

Abstract

This invention discloses a decomposition furnace for cement production, comprising a furnace body and a separator. A gasification decomposition chamber is formed within the furnace body. A feed inlet is located on one side of the furnace body, and a discharge outlet is located on the other side. A burner is installed within the gasification decomposition chamber, with an air inlet at one end and an exhaust outlet at the other. The separator includes a first feed pipe and a first exhaust pipe. The first feed pipe communicates with the discharge outlet, and the first exhaust pipe communicates with the air inlet of the burner. Cement raw materials undergo a decomposition reaction within the gasification decomposition chamber, and biomass raw materials undergo a gasification reaction within the gasification decomposition chamber. The decomposition reaction and the decomposed products after the gasification reaction are coupled. This decomposition furnace converts carbon dioxide into carbon monoxide using reducing gas generated from biomass gasification, which not only promotes the decomposition of calcium carbonate but also lowers the decomposition temperature.

Description

Technical Field

[0001] This invention relates to the field of cement production technology, and in particular to a decomposition furnace for cement production. Background Technology

[0002] Cement is an indispensable basic raw material in national economic construction, and as an important basic industry, cement production technology plays a crucial role. The main reaction in cement clinker production involves the combustion of calcium carbonate with coal to produce calcium oxide and carbon dioxide. However, the high concentration of carbon dioxide generated during this reaction causes calcium oxide to react with carbon dioxide again to form calcium carbonate (the reverse reaction), thus inhibiting calcium carbonate decomposition. To promote the forward reaction, the process operating temperature is often increased, leading to increased nitrogen oxide emissions and system energy consumption. Therefore, traditional cement raw material decomposition processes can no longer meet the requirements of modern green and low-carbon development. Thus, to achieve the goal of green and low-carbon development, one of the important means of emission reduction in the cement industry is to partially replace coal with biomass as fuel for the decomposition of calcium carbonate (the main component of cement raw materials), thereby reducing nitrogen oxide emissions. However, since the calcium carbonate decomposition reaction itself releases a large amount of carbon dioxide, the fuel substitution strategy has limited effect on reducing carbon dioxide emissions in the cement industry. Therefore, high temperature (>900℃), high energy consumption, and high carbon dioxide emissions remain persistent pain points for the cement industry. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a decomposition furnace for cement production, which converts carbon dioxide into carbon monoxide through reducing gases generated by biomass gasification, thereby not only promoting the decomposition of calcium carbonate but also reducing the decomposition temperature.

[0004] A cement production decomposition furnace according to an embodiment of the present invention includes:

[0005] The furnace body contains a gasification and decomposition chamber. One side of the furnace body has a feed inlet for cement raw materials and biomass feedstock to enter the gasification and decomposition chamber, and the other side has a discharge outlet. A burner is installed within the gasification and decomposition chamber, with an air inlet at one end and an exhaust outlet at the other end.

[0006] A separator is provided on the discharge port side of the furnace body. The separator includes a first feed pipe and a first exhaust pipe. The first feed pipe is connected to the discharge port, and the first exhaust pipe is connected to the air inlet of the burner.

[0007] The cement raw material undergoes a decomposition reaction in the gasification decomposition chamber, and the biomass raw material undergoes a gasification reaction in the gasification decomposition chamber. The decomposition reaction and the decomposed products after the gasification reaction are coupled. The coupled decomposed products undergo gas-solid separation through the separator. The separated combustible gas is burned and releases heat in the burner to provide heat for the decomposition reaction and gasification reaction in the furnace.

[0008] Therefore, by replacing biomass combustion with biomass gasification to participate in the decomposition of cement raw materials, the decomposition temperature of calcium carbonate can be effectively reduced, and the heat generated by the combustion of combustible gases can reduce energy consumption during cement clinker production, thereby improving the economic efficiency of each unit of cement clinker.

[0009] According to some embodiments of the present invention, the burner is in the shape of a straight tube and extends through the central region of the gasification decomposition chamber.

[0010] According to some embodiments of the present invention, the burner is provided with a medium element, which has a porous structure.

[0011] According to some embodiments of the present invention, it further includes a driver that drives the furnace body to rotate.

[0012] According to some embodiments of the present invention, a material lifting plate is provided in the gasification and decomposition chamber, one end of the material lifting plate is connected to the outer side wall of the burner, and the other end extends to the inner side wall of the gasification and decomposition chamber.

[0013] According to some embodiments of the present invention, it further includes: a cement raw material silo, wherein a preheating pipe is provided in the cement raw material silo, the preheating pipe passes through the central area of ​​the cement raw material silo, and one end of the preheating pipe is connected to the exhaust port of the burner.

[0014] According to some embodiments of the present invention, the preheating pipe is provided with a plurality of vent holes for direct heat exchange between high-temperature flue gas and cement raw materials.

[0015] According to some embodiments of the present invention, a screw feeder is provided at the bottom of the cement raw material silo. The screw feeder includes a discharge port and a conveying port. The conveying port is connected to the cement raw material silo, and the discharge port is connected to the feed port of the furnace body.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0018] Figure 1 This is a schematic diagram of the structure of a decomposition furnace for cement production according to an embodiment of the present invention.

[0019] Figure label:

[0020] 100. Decomposition furnace for cement production;

[0021] 1. Furnace body; 11. Gasification and decomposition chamber; 12. Feed inlet; 13. Discharge outlet; 2. Burner; 21. Air inlet; 22. Exhaust outlet; 23. Medium component; 24. Air inlet pipe; 3. Separator; 31. Feed pipe; 32. Air outlet pipe; 4. Driver; 5. Feeding plate; 6. Cement raw material silo; 7. Preheating pipe; 8. Screw feeder; 81. Conveying port; 82. Discharge port; 9. Biomass raw material silo. Detailed Implementation

[0022] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention are described in detail below.

[0023] The following is for reference. Figure 1 A decomposition furnace 100 for cement production according to an embodiment of the present invention is described.

[0024] Combination Figure 1 As shown, the cement production decomposition furnace 100 of this embodiment of the invention includes: a furnace body 1 and a separator 3 disposed at the bottom of the furnace body 1. A gasification decomposition chamber 11 is formed inside the furnace body 1. The gasification decomposition chamber 11 is provided with a feed inlet 12 and a discharge outlet 13. The feed inlet 12 is used to enter cement raw meal and biomass raw materials. The discharge outlet 13 is connected to the separator 3. In use, the cement raw meal undergoes a decomposition reaction in the gasification decomposition chamber 11, and the biomass raw materials undergo a gasification reaction in the gasification decomposition chamber 11. The decomposition reaction and the decomposed products after the gasification reaction are coupled together.

[0025] Separator 3 is located at the tail end of furnace body 1, i.e., on one side of the discharge port 13 of furnace body 1. Separator 3 is used for gas-solid separation. Specifically, separator 3 includes a feed pipe 31, a gas outlet pipe 32, and an ash discharge port. The feed pipe 31 is connected to the discharge port 13 of furnace body 1. In use, after the decomposition reaction and the gasification reaction are coupled in the gasification decomposition chamber 11, the coupled decomposed products will enter separator 3 through the gas inlet pipe, and then undergo gas-solid separation through separator 3. The separated gas will leave separator 3 through the gas outlet pipe 32, while the separated solids will leave through the ash discharge port at the bottom.

[0026] In addition, a burner 2 is provided in the gasification and decomposition chamber 11. One end of the burner 2 is connected to the gas outlet pipe 32 of the separator 3, and the other end extends out of the furnace body 1. At the same time, an air inlet pipe 24 is provided at the air inlet 21 of the burner 2. Through the air inlet pipe 24, outside air or combustion-supporting gas can be introduced into the burner 2. Since the separated gas contains a large amount of combustible gas, the combustible gas is fully burned under the action of the combustion-supporting gas, releasing a large amount of heat. This heat will radiate into the gasification and decomposition chamber 11, providing sufficient heat for the decomposition and gasification reactions in the furnace body 1.

[0027] In existing technologies, calcium carbonate is mixed and burned with a carbon source (coal or biomass) in a decomposition furnace. The combustion of the carbon source generates heat, which decomposes the calcium carbonate into calcium oxide and carbon dioxide. However, the combustion reaction of the carbon source produces a high concentration of carbon dioxide, creating a high-concentration carbon dioxide atmosphere. This causes calcium oxide to react with carbon dioxide again to form calcium carbonate (forming a reverse reaction), thus inhibiting the decomposition of calcium carbonate. In practice, to promote the reaction in the forward direction, the process operating temperature is usually increased, which significantly increases the system's energy consumption.

[0028] In this application, biomass is used as a carbon source, and a gasification reaction occurs within the furnace body 1. Specifically, the biomass is gasified at high temperatures to produce reducing molecules such as hydrogen and methane. Simultaneously, the cement raw materials undergo a decomposition reaction within the furnace body 1, generating calcium oxide and carbon dioxide at high temperatures. Furthermore, when the decomposition reaction and the decomposition products from the gasification reaction are coupled—hydrogen reacts with carbon dioxide from the decomposition of calcium carbonate at high temperatures to produce carbon monoxide and water, and methane reacts with carbon dioxide at high temperatures to produce carbon monoxide and hydrogen—the carbon dioxide produced during calcium carbonate decomposition is consumed by reducing molecules such as hydrogen and methane. This effectively promotes the forward decomposition of calcium carbonate, promotes the formation of calcium oxide, and lowers the decomposition temperature (under experimental conditions, calcium carbonate can undergo forward decomposition smoothly at an ambient temperature as low as 600 degrees Celsius), far lower than the decomposition temperatures of over 900 degrees Celsius in existing technologies.

[0029] As described above, the products of the gasification and decomposition reactions couple within the furnace body 1 to produce a large amount of combustible gases, namely carbon monoxide and hydrogen. These combustible gases, after gas-solid separation by separator 3, can be burned in burner 2, generating a large amount of heat to power the gasification and decomposition reactions. This self-supplied heat significantly reduces the consumption of additional energy, thereby lowering the energy consumption per unit of cement clinker produced.

[0030] Therefore, by replacing biomass combustion with biomass gasification to participate in the decomposition of cement raw materials, the decomposition temperature of calcium carbonate can be effectively reduced, and the heat generated by the combustion of combustible gases can reduce energy consumption during cement clinker production, thereby improving the economic efficiency of each unit of cement clinker.

[0031] Furthermore, based on the above embodiments, such as Figure 1 As shown, the burner 2 is a straight tube that runs through the central area of ​​the gasification and decomposition chamber 11. Specifically, the straight tube shape of the burner 2 facilitates the flow of combustible gas, reduces flow resistance, and allows the combustible gas to burn more smoothly in the burner 2.

[0032] Furthermore, based on the above embodiments, such as Figure 1 As shown, a medium element 23 is also provided inside the burner 2. This medium element 23 has a porous structure. During use, the combustible gas and the combustion-supporting gas burn inside the burner 2. The porous medium can act as a heat storage medium, making the combustible gas burn more evenly inside the burner 2. Specifically, the medium element 23 can be a honeycomb ceramic body or ceramic heat storage spheres.

[0033] In some embodiments of the present invention, such as Figure 1 As shown, the cement production decomposition furnace 100 also includes a driver 4, which drives the furnace body 1 to rotate. Specifically, the driver 4 may include a drive motor and a drive roller. A track ring is provided on the outer peripheral wall of the furnace body 1, and the drive roller is in close contact with the track ring. When the drive motor drives the drive roller to rotate, the drive roller drives the furnace body 1 to rotate. In use, after cement raw materials and biomass feedstock enter the furnace body 1, the continuous rotation of the furnace body 1 can achieve a mixing effect, thereby effectively promoting the coupling reaction between the decomposition reaction and the gasification reaction, and thus improving the conversion rate of calcium carbonate to calcium oxide.

[0034] Furthermore, based on the above embodiments, such as Figure 1 As shown, a lifting plate 5 is also provided inside the gasification and decomposition chamber 11. By setting the lifting plate 5, the cement raw meal and biomass raw materials can be better mixed, promoting the coupling reaction. Preferably, one end of the lifting plate 5 can be connected to the outer wall of the burner 2, and the other end can extend to the inner wall close to the gasification and decomposition chamber 11. The lifting plate 5 can be made of metal structural components. With such a structure and material setting, the heat in the burner 2 can be more effectively conducted to the gasification and decomposition chamber 11 through the lifting plate 5. At the same time, it also increases the thermal contact area of ​​the cement raw meal and biomass raw materials, promoting the decomposition and pyrolysis reactions.

[0035] In some embodiments of the present invention, such as Figure 1As shown, the cement production decomposition furnace 100 also includes a cement raw material silo 6, which is used to store cement raw materials. In order to facilitate better decomposition of cement raw materials in the gasification decomposition chamber 11, the cement raw materials can be preheated. Specifically, a preheating pipe 7 can be provided in the cement raw material silo 6. In use, hot flue gas can be introduced into the preheating pipe 7, and then the heat of the hot flue gas can be released into the cement raw material silo 6 to preheat the cement raw materials.

[0036] Preferably, the preheating pipe 7 can be passed through the central area of ​​the cement raw material silo 6, so as to release the heat in the preheating pipe 7 more evenly. More preferably, one end of the preheating pipe 7 is connected to the exhaust port 22 of the burner 2, so that the flue gas after combustion in the burner 2 is directly introduced into the preheating pipe 7, thereby playing the role of recovering and utilizing the flue gas temperature and reducing the consumption of additional energy.

[0037] Furthermore, based on the above embodiments, such as Figure 1 As shown, several vent holes are evenly distributed on the preheating pipe 7. When in use, the high-temperature flue gas in the preheating pipe 7 can be released into the cement raw material silo 6 through the vent holes, thereby directly contacting the cement raw material for heat exchange and improving the heat exchange efficiency.

[0038] In some embodiments of the present invention, such as Figure 1 As shown, a screw feeder 8 is provided at the bottom of the cement raw material silo 6. The screw feeder 8 includes a discharge port 82 and a conveying port 81. The conveying port 81 is connected to the cement raw material silo 6, and the discharge port 82 is connected to the feed port 12 of the furnace body 1. In use, the cement raw material enters the screw feeder 8 through the conveying port 81 and then falls into the feed port 12 of the furnace body 1 through the discharge port 82. By setting the screw feeder 8, the falling speed of the cement raw material can be controlled, thereby facilitating the control of the mixing ratio of cement raw material and biomass raw materials, which is beneficial to improving the production economy of calcium oxide.

[0039] Meanwhile, the decomposition furnace 100 for cement production also includes a biomass raw material silo 9, which can be set together with the cement raw material silo 6, so that the biomass raw material and cement raw material can enter the furnace body 1 together at the feed inlet 12, thereby realizing the pre-mixing of biomass raw material and cement raw material and promoting the coupling efficiency of decomposition reaction and pyrolysis reaction in the gasification decomposition chamber 11.

[0040] 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 do not 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.

[0041] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example.

[0042] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A decomposition furnace for cement production, characterized in that, include: A furnace body, wherein a gasification and decomposition chamber is formed within the furnace body, a feed inlet is provided on one side of the furnace body for cement raw materials and biomass feedstock to enter the gasification and decomposition chamber, and a discharge outlet is provided on the other side. A burner is installed within the gasification and decomposition chamber, with an air inlet at one end and an exhaust outlet at the other end. The burner is a straight tube and penetrates the central region of the gasification and decomposition chamber. A separator is provided on the discharge port side of the furnace body. The separator includes a feed pipe and an exhaust pipe. The feed pipe is connected to the discharge port, and the exhaust pipe is connected to the exhaust port of the burner. The cement raw material undergoes a decomposition reaction in the gasification decomposition chamber, and the biomass raw material undergoes a gasification reaction in the gasification decomposition chamber. The decomposition reaction and the decomposed products after the gasification reaction are coupled. The coupled decomposed products undergo gas-solid separation through the separator. The separated combustible gas is burned and releases heat in the burner to provide heat for the decomposition reaction and gasification reaction in the furnace.

2. The decomposition furnace for cement production according to claim 1, characterized in that, The burner contains a medium element, which has a porous structure.

3. The decomposition furnace for cement production according to claim 1, characterized in that, Also includes: A driver that drives the furnace body to rotate.

4. The decomposition furnace for cement production according to claim 3, characterized in that, The gasification and decomposition chamber is equipped with a material lifting plate. One end of the material lifting plate is connected to the outer wall of the burner, and the other end extends to the inner wall of the gasification and decomposition chamber.

5. The decomposition furnace for cement production according to claim 1, characterized in that, Also includes: A cement raw material silo, wherein a preheating pipe is provided in the cement raw material silo, the preheating pipe runs through the central area of ​​the cement raw material silo, and one end of the preheating pipe is connected to the exhaust port of the burner.

6. The decomposition furnace for cement production according to claim 5, characterized in that, The preheating pipe has several vent holes evenly distributed on it for direct heat exchange between high-temperature flue gas and cement raw materials.

7. The decomposition furnace for cement production according to claim 5, characterized in that, The bottom of the cement raw material silo is equipped with a screw feeder, which includes a discharge port and a conveying port. The conveying port is connected to the cement raw material silo, and the discharge port is connected to the feed port of the furnace body.

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