Low-carbon cement clinker preheating decomposition production system and production method

Abstract

The invention discloses a low-carbon cement clinker preheating and decomposing production system and method, and the system comprises preheating equipment for preheating to rapidly reach a decomposing temperature, and decomposing equipment for continuously heating and decomposing the preheated material, the collecting equipment is communicated with the gas outlet end of the decomposing equipment and is used for collecting decomposed gas and recycling decomposed materials, the decomposing equipment comprises a decomposing furnace, the decomposing furnace comprises an inner cylinder and an outer cylinder which are concentrically arranged, a decomposing cavity is formed between the wall surfaces of the inner cylinder and the outer cylinder, and the inner cylinder is communicated with the outer cylinder. The relatively closed decomposition cavity is jointly formed by the inner barrel and the outer barrel, so that materials can be heated and decomposed in the decomposition cavity, and the material distribution cavity is heated by fuel combustion, so that the materials are separated from fuel combustion flue gas, the recovery cost of carbon dioxide is greatly reduced, and the purity, whiteness and activity of the materials are also greatly improved; the added value of the product is increased, the economic benefit is improved, and the carbon emission is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of cement clinker production, and particularly relates to a low-carbon cement clinker preheating and decomposition production system and a production method. Background Art

[0002] At present, in the cement kiln and lime kiln industries, the cyclone preheater and decomposer used are such that the fuel burns at high temperature in the decomposer, and the high-temperature gas flow conducts heat to the material, causing the calcium carbonate material to decompose. The decomposed carbon dioxide is mixed with the gas from fuel combustion, resulting in low concentration and high impurities of the carbon dioxide decomposed from materials such as calcium carbonate. Basically, it is all discharged into the atmosphere. Even if carbon dioxide is recovered, the equipment investment for carbon dioxide purification is large, the purification process is complex, and the production cost is very high and uneconomical, causing great pressure on energy conservation and emission reduction. At the same time, the latent heat of the decomposition gas is not recovered and utilized, resulting in further increased energy consumption in cement clinker production. Summary of the Invention

[0003] Technical Objective: Aiming at the deficiencies in the existing cement clinker production, the present invention discloses a low-carbon cement clinker preheating and decomposition production system and a production method that can reduce production energy consumption and simultaneously achieve convenient collection of carbon dioxide.

[0004] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solution: A low-carbon cement clinker preheating and decomposition production system includes a preheating device for preheating to quickly reach the decomposition temperature, a decomposition device for further heating and decomposing the preheated material, and a collection device connected to the gas outlet end of the decomposition device for collecting decomposition gas and recovering decomposed material. The decomposition device includes a decomposer, and the decomposer includes a concentric inner cylinder and outer cylinder. A decomposition chamber is formed between the wall surfaces of the inner cylinder and the outer cylinder. An outlet pipe is provided at the upper part of the decomposition chamber. The material exchanges heat with the heat generated by fuel combustion through the wall surfaces of the inner cylinder and the outer cylinder in the decomposition chamber. An auxiliary mechanism for assisting the material to exchange heat is provided in the decomposition chamber.

[0005] Preferably, the auxiliary mechanism of the present invention includes a heat-conducting component extending from the inner wall surface of the outer cylinder towards the outer wall surface of the inner cylinder, heating the inside of the decomposition chamber through the heat-conducting component and exchanging heat with the contacting material.

[0006] Preferably, an air inlet for introducing a part of the decomposition gas collected by the collection device is provided at the bottom of the decomposition chamber of the present invention, and the decomposed gas blows the material to be dispersed in the decomposition chamber for heat exchange.

[0007] Preferably, spiral blades for guiding the intake air are provided on the outer wall surface of the inner cylinder of the present invention. The air inlet is arranged tangentially along the bottom of the spiral blades, and the air flow blows the material to be suspended and boiled for heat exchange.

[0008] Preferably, the heat-conducting component of the present invention adopts a steel grid, one end of the steel grid is fixed on the inner wall of the outer cylinder, and the other end is located on the outer periphery of the spiral blade. The material rises along the spiral blade under the blowing of the tangential air flow at the air inlet, and exchanges heat through the steel grid.

[0009] Preferably, the present invention has two sets of decomposition furnaces, namely a first decomposition furnace and a second decomposition furnace. The first decomposition furnace is connected to the preheating device, the second decomposition furnace is connected to the collection device, and the decomposition chamber of the first decomposition furnace is connected to the decomposition chamber of the second decomposition furnace through the outlet end. The material is heated and decomposed in the first decomposition furnace, and the separation of the finished product material and the decomposition gas is carried out in the second decomposition furnace.

[0010] Preferably, an aggregate side chamber is arranged on the outer cylinder of the second decomposition furnace of the present invention, and there is a side chamber passage opening between the aggregate side chamber and the decomposition chamber of the second decomposition furnace; a discharge port communicating with the material finished product collection area of the collection device is arranged at the bottom of the aggregate side chamber.

[0011] Preferably, the collection device of the present invention includes a bag filter connected to the outlet pipe of the second decomposition furnace, a decomposition gas collection device and a finished product bin. The finished product bin is connected to the discharge port of the aggregate side chamber and the discharge port of the bag filter. The decomposition gas collection device is provided with a gas supply pipe connected to the air inlet of the corresponding decomposition furnace; the gas enters the bag filter for dust removal and then enters the decomposition gas collection device; a cyclone dust collector is arranged at the inlet of the bag filter, and the decomposition gas first enters the cyclone dust collector for dust separation to collect the residual material finished product in the gas.

[0012] The present invention discloses a production method for preheating and decomposing low-carbon cement clinker. Using the above-mentioned production system for preheating and decomposing low-carbon cement clinker, the material is heated to the decomposition temperature by the preheating device and then enters the decomposition chamber of the decomposition furnace, and heat exchange is carried out through the wall surface of the decomposition chamber and the heat generated by the external fuel combustion. The material is heated and decomposed into decomposition gas and material finished product, and the separation of the material finished product and the decomposition gas is carried out by the collection device.

[0013] Preferably, when the material of the present invention exchanges heat in the decomposition chamber, the decomposition gas entering from the bottom of the decomposition chamber blows the material, and the spiral blade on the outer wall of the inner cylinder guides the material, so that the material is dispersed in the decomposition chamber and evenly heated and decomposed in the decomposition chamber.

[0014] Beneficial effects: The production system and production method for preheating and decomposing low-carbon cement clinker disclosed by the present invention have the following beneficial effects: 1. The present invention forms a relatively closed decomposition cavity by using an inner cylinder and an outer cylinder, enabling the material to be thermally decomposed within the decomposition cavity. The fuel combustion is used to heat the material separation cavity, achieving the separation of the material from the fuel combustion flue gas. Under the condition of isolating external air, oxides (such as calcium oxide and magnesium oxide) and high-concentration carbon dioxide are decomposed, greatly reducing the recovery cost of carbon dioxide, significantly improving the purity, whiteness, and activity of the material, increasing the added value of the product, improving economic efficiency, and reducing carbon emissions.

[0015] 2. The present invention is provided with an auxiliary mechanism in the decomposition cavity to assist in the heat exchange of the material. The auxiliary mechanism adopts a heat-conducting component extending into the material separation cavity, thereby improving the uniformity of heating the material and ensuring the decomposition effect and production efficiency.

[0016] 3. The present invention high-speed transports a part of the decomposed gas collected into the decomposition cavity, introducing it tangentially along the spiral blades. The material falling into the decomposition cavity is suspended and boiled in the decomposition cavity under the blowing of the air flow, thereby improving the uniformity of heat exchange and enabling the material to be fully decomposed.

[0017] 4. The heat-conducting component of the present invention adopts a steel grid, and the end of the steel grid is located on the outer periphery of the spiral blades. When the air intake blows, it drives the material to move along the guidance of the spiral blades. When the material passes through the steel grid, it will contact the steel grid area for heat exchange. In addition to guiding the movement of the material, the spiral blades can also play a role in heat conduction, introducing the heat on the inner cylinder into the decomposition cavity and further enhancing the uniformity of heating the material.

[0018] 5. The present invention uses two sets of decomposition furnaces. The first decomposition furnace is used for heating and decomposing the material, and the second decomposition furnace is used for decomposing the remaining material and collecting the decomposed material product, realizing the separation of the material product from the decomposed gas; the separation is achieved by using the furnace body structure of the second decomposition furnace. Compared with the method of separating by using dust removal equipment, it can reduce the working load of the dust removal equipment and also reduce the risk of blockage.

[0019] 6. A part of the carbon dioxide in the present invention is returned to the decomposition furnace as power to play a role in suspending and boiling the material, recycling heat energy and wind energy, isolating external air, improving the energy utilization efficiency, and the concentration of the recovered carbon dioxide can reach more than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art.

[0021] Figure 1 It is the structure diagram of the preheating equipment of the present invention; Figure 2 It is the schematic diagram of the structure of the decomposition furnace of the present invention; Figure 3 This is a schematic cross-sectional view of the second decomposing furnace of the present invention; Among them, 1-inner cylinder, 2-outer cylinder, 3-decomposing chamber, 4-outlet pipe, 5-thermal conduction component, 6-air inlet, 7-spiral blade, 8-first decomposing furnace, 9-second decomposing furnace, 10-aggregate side chamber, 11-side chamber passage opening, 12-discharge port, 13-bag filter, 14-decomposed gas collection device, 15-cyclone dust collector. Specific embodiments

[0022] Now, reference will be made in detail to the embodiments of the present disclosure, one or more examples of which are set forth below. Each embodiment and example is provided by way of explanation of the devices, components, and materials of the present disclosure, and not by way of limitation. On the contrary, the following description provides a convenient illustration for implementing the exemplary embodiments of the present disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made within the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0023] As Figures 1 - 3 shown, the present invention discloses a low-carbon cement clinker preheating and decomposing production system, including preheating equipment for preheating to quickly reach the decomposition temperature, decomposing equipment for continuously heating and decomposing the preheated material, and collection equipment connected to the gas outlet end of the decomposing equipment for decomposing gas collection and decomposing material recovery. The preheating equipment adopts a multi-stage suspension preheating method, including cyclones C1, C2, C3, C4, C5. The decomposing equipment includes a decomposing furnace, which includes an inner cylinder 1 and an outer cylinder 2 arranged concentrically. A decomposing chamber 3 is formed between the wall surfaces of the inner cylinder 1 and the outer cylinder 2. An outlet pipe 4 is arranged at the upper part of the decomposing chamber 3. After multi-stage preheating, the material enters the decomposing chamber 3 from the cyclone C4. In the decomposing chamber 3, heat exchange is carried out between the wall surfaces of the inner cylinder 1 and the outer cylinder 2 and the heat generated by fuel combustion. The high-temperature flue gas generated by fuel combustion can be introduced into a preset device and flow into the cyclone C4 to be used as the heat source of the suspension preheater to preheat the material in each process above, recycle heat, save energy, reduce production costs, reduce the use of external fuel, and reduce carbon emissions; an auxiliary mechanism for assisting the material in heat exchange is arranged in the decomposing chamber 3.

[0024] In an embodiment of the present invention, as Figure 2As shown, the inner cylinder 1 adopts a hollow structure, forming a first combustion chamber inside the inner cylinder 1. A second combustion chamber is formed by surrounding the outside of the outer cylinder 2 with heat-insulating refractory materials. Combustion nozzles are provided at the bottom and side walls of the first combustion chamber and the second combustion chamber. Fuel and oxygen-rich air are fed into the combustion chambers through the combustion nozzles for combustion heating. The heat is transferred into the decomposition chamber 3 through the walls of the inner cylinder 1 and the outer cylinder 2 for heating, so that the material is decomposed. During this process, the material is in an independent space and does not contact the flue gas generated by the fuel combustion. Thus, the gas decomposed from the material can be directly collected, while the flue gas generated by combustion can be separately transported through pipelines or collected and then uniformly transported to the cyclone C4 for preheating the material.

[0025] To ensure the heating and decomposition effect of the material, an auxiliary mechanism is used to enable the material to fully exchange heat. The auxiliary mechanism of the present invention includes a heat-conducting component 5 extending from the inner wall surface of the outer cylinder 2 towards the outer wall surface of the inner cylinder 1. The decomposition chamber 3 inside is heated through the heat-conducting component 5 and heat exchange is carried out with the contacted material. The heat-conducting component 5 is located inside the decomposition chamber 3 and can be used as an extension of the wall surface, making the temperature distribution in each part of the decomposition chamber uniform, uniformly heating and decomposing the material everywhere, and improving the decomposition effect.

[0026] The present invention is used for the processing of cement clinker, and the material is limestone powder. For other production objects, corresponding materials such as dolomite, magnesite, calcium-containing coal gangue, etc. can also be used, and the protection scope of the present invention is not affected by the change of the material object.

[0027] To prevent the material from depositing at the bottom of the decomposition chamber, resulting in poor decomposition effect in the middle part, an air inlet 6 for introducing part of the decomposed gas collected by the collecting device is provided at the bottom of the decomposition chamber 3 of the present invention. The material is blown and dispersed in the decomposition chamber 3 through the decomposed gas for heat exchange. Using the airflow to blow can reduce the accumulation of the material. At the same time, the decomposed gas used is the decomposed gas collected by the collecting device, which can ensure the purity of the gas components in the decomposition chamber and make full use of the latent heat of the gas, reduce the recovery cost of the decomposed gas, and ensure the purity and whiteness of the material.

[0028] On the outer wall surface of the inner cylinder body 1 of the present invention, spiral blades 7 for guiding the intake air are provided, and the air inlet 6 is arranged tangentially along the bottom of the spiral blades 7. Heat exchange is carried out by blowing the material to be suspended and boiled by the air flow; the heat conduction component 5 is made of a steel grid. One end of the steel grid is fixed on the inner wall of the outer cylinder body 2, and the other end is located on the outer circumference of the spiral blades 7. The material rises along the spiral blades 7 under the blowing of the tangential air flow at the air inlet 6 and exchanges heat through the steel grid. The steel grid is preferably arranged according to the pitch size of the spiral blades 7, and one steel grid corresponds to each pitch position. Moreover, the surface of the steel grid corresponds to the spiral movement direction of the material when it is blown, so as to increase the contact heat exchange area with the material and realize the uniform heating and decomposition of each part of the material.

[0029] To facilitate the collection of the material finished product, enable it to be separated from the decomposition gas, and avoid the blockage problem that occurs when using a dust removal device for separation, the number of decomposition furnaces of the present invention is two groups, namely the first decomposition furnace 8 and the second decomposition furnace 9. The first decomposition furnace 8 is connected to the preheating device, and the second decomposition furnace 9 is connected to the collection device. The decomposition chamber of the first decomposition furnace 8 is connected to the decomposition chamber of the second decomposition furnace 9 through the outlet end. The material is heated and decomposed in the first decomposition furnace 8, and the separation of the finished material and the decomposition gas is carried out in the second decomposition furnace 9. The first decomposition furnace 8 only heats and decomposes the material. After most of the material is decomposed, under the blowing of the air flow and the suction provided by the collection device, the material can enter the second decomposition furnace 9 from the outlet pipe of the first decomposition furnace 8. The second decomposition furnace 9 is mainly used for the separation of the material finished product and the decomposition gas, and also has the function of further heating and decomposing the participating material.

[0030] An aggregate side cavity 10 is arranged on the outer cylinder body of the second decomposition furnace 9 of the present invention. A side cavity channel opening 11 is provided between the aggregate side cavity 10 and the decomposition chamber of the second decomposition furnace 9; a discharge port 12 communicating with the material finished product collection area of the collection device is arranged at the bottom of the aggregate side cavity 10. When the material finished product moves along the guidance of the spiral blades under the blowing of the intake air flow at the air inlet, the material finished product ash enters the aggregate side cavity 10 through the side cavity channel opening 11. Since the aggregate side cavity 10 is separated from the decomposition chamber 3 by the wall surface of the outer cylinder body 2 except for the side cavity channel opening 11, the material finished product entering the aggregate side cavity 10 will settle in the cavity of the aggregate side cavity 10, and is not affected by the blowing of the intake air at the air inlet 6 and the spiral blades, so as to realize the separation of the material finished product and the decomposition gas. The collected material finished product is discharged through the discharge port 12.

[0031] The collection device of the present invention includes a bag filter 13, a decomposition gas collection device 14, and a finished product bin, which are connected to the outlet pipe of the second decomposition furnace 9. The finished product bin is connected to the discharge port 12 of the aggregate side cavity and the discharge port of the bag filter 13. The decomposition gas collection device 14 is provided with a gas supply pipe connected to the intake port of the corresponding decomposition furnace. The gas enters the bag filter 13 for dust removal and then enters the decomposition gas collection device 14. A cyclone dust collector 15 is provided at the inlet of the bag filter 13. The decomposition gas first enters the cyclone dust collector 15 for dust separation to collect the residual material finished products in the gas.

[0032] The present invention also discloses a method for preheating and decomposing low-carbon cement clinker. Using the above-mentioned low-carbon cement clinker preheating and decomposing production system, the material is heated to the decomposition temperature by the preheating device and then enters the decomposition cavity of the decomposition furnace. The specific process is as follows: The material first enters the heat exchange rising pipe of the C2 cyclone, then enters the C1 cyclone along with the air flow, is captured and collected in the C1 cylinder, and then enters the C3 heat exchange rising pipe through the feeding pipe, then enters the C2 cyclone along with the air flow, is captured and collected in the C2 cylinder, and then enters the C4 heat exchange rising pipe through the feeding pipe, then enters the C3 cyclone along with the air flow, is captured and collected in the C3 cylinder, and then enters the C5 heat exchange rising pipe through the feeding pipe, then enters the C4 cyclone along with the air flow, is captured and collected in the C4 cyclone, and then enters the decomposition furnace through the feeding pipe of the C4 cyclone. Heat exchange is carried out through the wall surface of the decomposition cavity and the heat generated by the external fuel combustion. The material is heated and decomposed into decomposition gas and material finished products, and the separation of the material finished products and the decomposition gas is carried out by the collection device.

[0033] When the material of the present invention exchanges heat in the decomposition cavity, the decomposition gas entering from the bottom of the decomposition cavity blows the material, and the spiral blades on the outer wall of the inner cylinder guide the material, so that the material is dispersed in the decomposition cavity and evenly heated and decomposed in the decomposition cavity. The gas introduced into the decomposition cavity adopts a pulsed introduction method to intermittently blow the material.

[0034] Taking the production of cement clinker as an example, after the materials are preheated and enter the first decomposing furnace 8, a part of the carbon dioxide gas discharged from the bag filter is introduced at a high speed tangentially, and the remaining gas enters the decomposition gas collection device for purification treatment to obtain high-concentration carbon dioxide; the gas introduced into the decomposition chamber 3 forces the materials on the spiral blades to be suspended, homogenized, evenly heated, and decomposed synchronously. The materials come into full contact with the high-temperature-resistant steel grids and are decomposed by heat. The decomposed carbon dioxide gas and the fine powder material products enter the second decomposing furnace 9 under the strong suction of the bag filter 13. The decomposition process of the materials in the second decomposing furnace 9 is similar to that in the first decomposing furnace 8, and the participating materials can be further heated and decomposed. The material products will enter the aggregate side chamber 10 under the carbon dioxide blast of the second decomposing furnace and accumulate at the bottom discharge port 12 due to the self-weight of the materials. The discharge port 12 is equipped with an air-lock dividing wheel to convey the decomposed materials to the corresponding finished product silos, and the gas will enter the cyclone separator 15 and the bag filter 13 accordingly. The material products contained in the gas are also separated and collected and sent into the finished product silos.

Claims

1. A low-carbon cement clinker preheating and decomposition production system, characterized in that: The invention comprises a preheating device for preheating materials to quickly reach a decomposition temperature, a decomposition device for continuing to heat and decompose the preheated materials, and a collection device connected to a gas outlet end of the decomposition device for collecting decomposed gas and recovering decomposed materials. The decomposition device comprises a decomposition furnace, the decomposition furnace comprises an inner cylinder (1) and an outer cylinder (2) arranged concentrically, a decomposition chamber (3) is formed between the walls of the inner cylinder (1) and the outer cylinder (2), an outlet pipe (4) is arranged at the top of the decomposition chamber (3), and the materials in the decomposition chamber (3) exchange heat with the heat generated by fuel combustion through the walls of the inner cylinder (1) and the outer cylinder (2); an auxiliary mechanism for assisting the materials in heat exchange is arranged in the decomposition chamber (3).

2. A low carbon cement clinker preheating and decomposition production system according to claim 1, characterized in that: The auxiliary mechanism comprises a heat-conducting component (5) extending along the inner wall of the outer cylinder (2) towards the outer wall of the inner cylinder (1), and the heat-conducting component (5) is used to heat the interior of the decomposition chamber (3) and to perform heat exchange with contacting materials.

3. A low carbon cement clinker preheating and decomposition production system according to claim 2, characterized in that: The bottom of the decomposition chamber (3) is provided with an air inlet (6) for introducing part of the decomposition gas collected by the collection device, and the decomposition gas is blown into the material to disperse in the decomposition chamber (3) for heat exchange.

4. A low carbon cement clinker preheating and decomposition production system according to claim 3, characterized in that: A spiral blade (7) for guiding the intake air is arranged on the outer wall surface of the inner cylinder (1), and the air inlet (6) is arranged tangentially along the bottom of the spiral blade (7), so that the material is suspended and boiled by air flow to exchange heat.

5. A low carbon cement clinker preheating and decomposition production system according to claim 4, characterized in that: The heat-conducting component (5) is a steel grid, one end of which is fixed to the inner wall of the outer cylinder (2), and the other end of which is located at the outer periphery of the spiral blade (7). The material rises along the spiral blade (7) under the influence of the tangential airflow from the air inlet (6) and exchanges heat through the steel grid.

6. A low carbon cement clinker preheating and decomposition production system according to any one of claims 2 to 5, characterized in that: The number of the decomposition furnaces is two groups, namely a first decomposition furnace (8) and a second decomposition furnace (9), wherein the first decomposition furnace (8) is connected to a preheating device, and the second decomposition furnace (9) is connected to a collecting device, and the decomposition chamber of the first decomposition furnace (8) is connected to the decomposition chamber of the second decomposition furnace (9) through an outlet end, and the material is heated and decomposed in the first decomposition furnace (8), and the finished material and the decomposition gas are separated in the second decomposition furnace (9).

7. A low carbon cement clinker preheating and decomposition production system according to claim 6, characterized in that: The outer cylinder of the second decomposition furnace (9) is provided with a material collection side chamber (10), and a side chamber passage opening (11) is provided between the material collection side chamber (10) and the decomposition chamber of the second decomposition furnace (9); a discharge opening (12) connected to a material finished product collection area of ​​a collection device is provided at the bottom of the material collection side chamber (10).

8. A low carbon cement clinker preheating and decomposition production system according to claim 7, characterized in that: The collecting device comprises a bag dust collector (13) connected to the outlet pipe of the second decomposition furnace (9), a decomposition gas collecting device (14) and a finished product bin; the finished product bin is connected to the discharge port (12) of the collecting side chamber and the discharge port of the bag dust collector (13); the decomposition gas collecting device (14) is provided with an air supply pipe connected to the air inlet of the corresponding decomposition furnace; the gas enters the bag dust collector (13) for dust removal and then enters the decomposition gas collecting device (14); a cyclone dust collector (15) is arranged at the inlet of the bag dust collector (13); the decomposition gas first enters the cyclone dust collector (15) for dust removal and separation, and the residual finished product in the gas is collected.

9. A method for preheating and decomposing low-carbon cement clinker, using the low-carbon cement clinker preheating and decomposition production system according to any one of claims 1 to 8, characterized in that: After being heated to the decomposition temperature by the preheating equipment, the material enters the decomposition chamber of the decomposition furnace, and heat is exchanged with the heat generated by the combustion of the external fuel through the wall of the decomposition chamber. The material is heated and decomposed into decomposition gas and finished material. The finished material and decomposition gas are separated by the collecting equipment.

10. A method for producing low carbon cement clinker by preheating and decomposing according to claim 9, characterized in that: When the material is exchanging heat in the decomposition chamber, the decomposition gas entering from the bottom of the decomposition chamber blows the material and guides the material through the spiral blades on the outer wall of the inner cylinder, so that the material is dispersed in the decomposition chamber and evenly decomposed by heat in the decomposition chamber.

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