A cement production system based on biomass co-pyrolysis

Abstract

The application discloses a cement production system based on biomass co-pyrolysis, which comprises a decomposing furnace and a rotary kiln, wherein the decomposing furnace is internally provided with a decomposing chamber, and the decomposing chamber is provided with a first feeding port, a second feeding port, a first discharging port and a first gas outlet; the rotary kiln is internally provided with a calcining chamber, one side of the calcining chamber is provided with a flame spouting port and a second discharging port, the other side of the calcining chamber is provided with a third feeding port, the third feeding port is communicated with the first discharging port, the flame spouting port is communicated with the first gas outlet, and the second discharging port is communicated with the second feeding port. Thus, by utilizing the coupling effect between the gasification reaction of biomass and the decomposition reaction of cement raw material, the decomposition reaction of cement raw material is effectively promoted to proceed in a positive direction, the decomposition temperature of calcium carbonate can be reduced, and the economy of per unit cement clinker can be improved.

Description

Technical Field

[0001] This invention relates to the field of cement production technology, and in particular to a cement production system based on biomass co-pyrolysis. 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 can cause calcium oxide to react with carbon dioxide again to form calcium carbonate (the reverse reaction), thus inhibiting the decomposition of calcium carbonate.

[0003] To promote the forward reaction, the process operating temperature is often increased, which in turn increases nitrogen oxide emissions and greatly increases the energy consumption of the cement production system. Therefore, traditional cement raw material production can no longer meet the requirements of modern green and low-carbon development.

[0004] Therefore, in order to meet the goal of green and low-carbon development, existing technologies often use biomass to partially replace coal as fuel. However, the calorific value of biomass is lower than that of coal, and the combustion of biomass also releases a large amount of carbon dioxide, resulting in very high energy consumption in cement production. The biomass fuel substitution strategy has very limited effect on reducing carbon dioxide emissions in the cement industry. As a result, high temperature (>900℃), high energy consumption and high carbon dioxide emissions have always been the challenges in cement production. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a cement production system based on biomass co-pyrolysis.

[0006] A cement production system based on biomass co-pyrolysis according to an embodiment of the present invention includes:

[0007] A decomposition furnace, wherein a decomposition chamber is provided inside the decomposition furnace, and a first feed inlet, a second feed inlet, a first discharge outlet and a first gas outlet are provided on the decomposition chamber;

[0008] A rotary kiln, wherein a calcination chamber is provided inside the rotary kiln, a flame outlet and a second discharge outlet are provided on one side of the calcination chamber, and a third feed outlet is provided on the other side. The third feed outlet is connected to the first discharge outlet, the flame outlet is connected to the first air outlet, and the second discharge outlet is connected to the second feed outlet.

[0009] In this process, cement raw materials and biomass undergo a coupled reaction in the decomposition furnace. The coupled gaseous products are fully combusted in the rotary kiln, and the coupled solid products are calcined in the rotary kiln. Some of the calcined high-temperature solid products release heat in the decomposition furnace.

[0010] According to some embodiments of the present invention, the product further includes: a cooling furnace, wherein a cooling chamber is provided inside the cooling furnace, the cooling chamber is connected to the second discharge port, and an air inlet and an air outlet are provided on the cooling chamber, wherein cold air enters through the air inlet and cools the calcined solid product.

[0011] According to some embodiments of the present invention, the cooling furnace is a grate cooling furnace, the air inlet is located at the bottom of the grate cooling furnace, and the air outlet is located at the top of the grate cooling furnace.

[0012] According to some embodiments of the present invention, the device further includes a preheating furnace, the preheating furnace including an air inlet and a third discharge outlet, the air outlet being connected to the air inlet, and the third discharge outlet being connected to the first discharge outlet.

[0013] According to some embodiments of the present invention, the preheating furnace includes a second feed box, a second rotary furnace body, and a second discharge box. The two ends of the second rotary furnace body are dynamically sealed to the second feed box and the second discharge box, respectively. The air inlet is provided on the second discharge box, and the third discharge port is provided on the second discharge box.

[0014] According to some embodiments of the present invention, the decomposition furnace includes: a first feed box, a first rotary furnace body, and a first discharge box. The two ends of the first rotary furnace body are dynamically sealed to the first feed box and the first discharge box, respectively. The decomposition chamber is formed by the first feed box, the first rotary furnace body, and the first discharge box. The first air outlet is located at the top of the first discharge box, the first discharge port is located at the bottom of the first discharge box, and the first feed port and the second feed port are both located on the first feed box.

[0015] According to some embodiments of the present invention, it further includes: a feeding device and a hopper, one end of the feeding device being connected to the hopper and the other end being connected to the first feed box.

[0016] In some embodiments of the present invention, the feeding device is a screw feeder.

[0017] Beneficial effects

[0018] By utilizing the coupling effect between the gasification reaction of biomass and the decomposition reaction of cement raw materials, the forward decomposition reaction of cement raw materials can be effectively promoted. This not only lowers the decomposition temperature of calcium carbonate, but also reduces the energy consumption during the calcination of cement raw materials through the heat generated by the complete combustion of combustible gases, thereby improving the economic efficiency of each unit of cement clinker. Attached Figure Description

[0019] 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:

[0020] Figure 1 This is a schematic diagram of a cement production system based on biomass co-pyrolysis according to an embodiment of the present invention.

[0021] Figure label:

[0022] 100. Cement production system based on biomass co-pyrolysis;

[0023] 1. Decomposition furnace; 11. First feed box; 111. First feed inlet; 112. Second feed inlet; 12. First rotary furnace body; 13. First discharge box; 131. First gas outlet; 132. First discharge outlet;

[0024] 2. Rotary kiln; 21. Flame nozzle; 22. Second discharge port; 23. Third feed port;

[0025] 3. Preheating furnace; 31. Second feed box; 32. Second rotary furnace body; 33. Second discharge box; 331. Air inlet; 332. Third discharge outlet;

[0026] 4. Cooling furnace; 41. Air inlet; 42. Air outlet;

[0027] 5. Feeding device; 6. Hopper. Detailed Implementation

[0028] 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.

[0029] The following is for reference. Figure 1 A cement production system 100 based on biomass co-pyrolysis according to an embodiment of the present invention is described.

[0030] Combination Figure 1 As shown, the cement production system 100 based on biomass co-pyrolysis of this invention includes a decomposition furnace 1 and a rotary kiln 2. The decomposition furnace 1 is provided with a decomposition chamber, which is provided with a first feed inlet 111, a second feed inlet 112, a first discharge outlet 132 and a first gas outlet 131. The rotary kiln 2 is provided with a calcination chamber, which is provided with a flame outlet 21 and a second discharge outlet 22 on one side and a third feed inlet 23 on the other side. The third feed inlet 23 is connected to the first discharge outlet 132, the flame outlet 21 is connected to the first gas outlet 131, and the second discharge outlet 22 is connected to the second feed inlet 112. Cement raw materials and biomass undergo a coupling reaction in the decomposition furnace 1. The coupled gaseous products are fully combusted in the rotary kiln 2, and the coupled solid products are calcined in the rotary kiln 2. Some of the calcined solid products release heat in the decomposition furnace 1.

[0031] During use, cement raw materials undergo decomposition in the decomposition chamber, while biomass undergoes gasification. The decomposition and gasification products are coupled: specifically, biomass gasifies at high temperatures to produce reducing molecules such as hydrogen and methane, while cement raw materials decompose at high temperatures to produce calcium oxide and carbon dioxide. When this coupling occurs, hydrogen reacts with carbon dioxide from calcium carbonate decomposition to produce carbon monoxide and water, and methane reacts with carbon dioxide to produce carbon monoxide and hydrogen. Thus, the carbon dioxide produced during calcium carbonate decomposition is consumed by reducing molecules like hydrogen and methane, effectively promoting the forward decomposition of calcium carbonate, promoting calcium oxide formation, and lowering the decomposition temperature (under experimental conditions, calcium carbonate can undergo forward decomposition smoothly at ambient temperatures as low as 700℃), far below the existing decomposition temperatures exceeding 900℃.

[0032] The products of gasification and decomposition reactions undergo a coupled reaction in the decomposition chamber, producing a large amount of combustible gases, namely carbon monoxide and hydrogen. These combustible gases are introduced into the rotary kiln 2 and can be fully combusted to generate a large amount of heat, which can supplement the energy consumed by the rotary kiln 2 when calcining raw materials. Through this self-supplied heat, the energy consumption of the rotary kiln 2 can be greatly reduced, thereby reducing the energy consumption per unit of cement clinker produced.

[0033] In addition, the temperature of cement raw meal can reach 1400 degrees Celsius when it is calcined in rotary kiln 2. Therefore, the temperature of cement raw meal after calcination will also be very high. By returning part of the calcined cement raw meal to decomposition furnace 1, the high temperature heat carried by this part of the material can be used to directly release heat in decomposition furnace 1, thereby supplementing or even maintaining the energy consumption in decomposition furnace 1, thus effectively reducing the energy consumption of the entire cement production system.

[0034] Therefore, by utilizing the coupling effect between the gasification reaction of biomass and the decomposition reaction of cement raw materials, the forward decomposition reaction of cement raw materials can be effectively promoted. This not only lowers the decomposition temperature of calcium carbonate, but also reduces the energy consumption during the calcination of cement raw materials by using the heat generated after the complete combustion of combustible gases, thereby improving the economic efficiency of producing each unit of cement clinker.

[0035] Furthermore, based on the above embodiments, the biomass co-pyrolysis-based cement production system 100 also includes a cooling furnace 4, wherein the cooling furnace 4 is provided with a cooling chamber, which is connected to the second discharge port 22. The cooling chamber is provided with an air inlet 41 and an air outlet 42. In use, the calcined cement material is discharged from the rotary kiln 2 into the cooling furnace 4 for cooling and temperature reduction. That is, cold air enters the cooling furnace 4 through the air inlet 41. When the cold air flows through the cement material, heat exchange occurs. The cold air after heat exchange leaves the cooling furnace 4 through the air outlet 42, thereby achieving the cooling of the cement material, thereby increasing the cooling speed, facilitating the rapid collection and storage of cement clinker, and thus improving the production efficiency of the cement production system.

[0036] Preferably, the cooling furnace 4 is a grate cooling furnace, with the air inlet 41 located at the bottom of the grate cooling furnace and the air outlet 42 located at the top of the grate cooling furnace. In use, the calcined cement material is spread on the grate with a certain thickness and moves forward continuously with the movement of the grate. After entering the furnace, the cold air passes through the material layer perpendicular to the movement direction of the cement material. This results in higher heat exchange efficiency and is more conducive to the cooling of the cement material near the surface of the grate, resulting in a better cooling effect.

[0037] Furthermore, based on the above embodiments, the biomass co-pyrolysis-based cement production system also includes a preheating furnace 3, which includes an air inlet 331 and a third discharge outlet 332. The air outlet 42 of the cooling furnace 4 is connected to the air inlet 331 of the preheating furnace 3, and the third discharge outlet 332 is connected to the first feed inlet 111. In use, when the cold air in the cooling furnace 4 exchanges heat with the high-temperature cement material, it becomes hot air. This hot air is then introduced into the preheating furnace 3, where the heat carried by the hot air can be used to heat the cement raw materials, thereby improving the decomposition reaction efficiency of the heated cement raw materials in the decomposition furnace 1.

[0038] More specifically, in actual production, while cooling the calcined cement material with cold air, the cold air is converted into hot air through heat exchange. The temperature of the calcined cement material can usually reach 1400℃ or higher. In this way, the hot air after heat exchange can easily raise the temperature of the cement raw material in the preheating furnace 3 to about 500℃. However, the decomposition temperature of the cement raw material in the decomposition furnace 1 in this application can be as low as below 700℃. Therefore, by utilizing waste heat to raise the temperature of the cement raw material in the preheating furnace 3 to about 400-500℃, not only can the decomposition reaction of the cement raw material be avoided, but also some of the heat in the hot air can be recovered, reducing the energy consumption of the entire production system.

[0039] Meanwhile, since the cement raw materials have been preheated to near the critical temperature of the reaction, returning some of the calcined high-temperature cement material to the decomposition furnace 1 can easily raise the temperature inside the decomposition furnace 1 to over 700°C through its own high-temperature heat, thus allowing the decomposition reaction to proceed smoothly.

[0040] Under certain conditions, the energy carried by some of the calcined high-temperature cement material can fill the energy gap required in the decomposition furnace 1, thereby achieving a balance between energy consumption and energy replenishment in the decomposition furnace 1 and further reducing the energy consumption of the entire production system.

[0041] It should be noted that the preheated cement raw meal and biomass are fed into the decomposition furnace separately. This makes it easier to control the feeding ratio between cement raw meal and biomass. Moreover, the biomass is not preheated before entering the decomposition furnace, so the moisture content of the biomass itself is conducive to the gasification reaction, thereby improving the coupling efficiency between the decomposition reaction and the gasification reaction.

[0042] In some embodiments of the present invention, such as Figure 1 As shown, the preheating furnace 3 includes a second feed box 31, a second rotary furnace body 32, and a second discharge box 33. The two ends of the second rotary furnace body 32 are dynamically sealed to the second feed box 31 and the second discharge box 33, respectively. The air inlet 331 is located on the second discharge box 33, and the third discharge port 332 is located on the second discharge box 33.

[0043] Specifically, after the materials (biomass and cement raw meal) enter the preheating furnace 3, they are heated by the continuous intake of air through the air inlet 331. During this process, the biomass and cement raw meal move from the second feed box 31 to the second discharge box 33, and the hot air flows from the second discharge box 33 to the second feed box 31, which causes the materials and hot air to move relative to each other. This allows the hot air to come into direct contact with the materials, thereby greatly improving the heating efficiency.

[0044] Similarly, the decomposition furnace 1 includes a first feed box 11, a first rotary furnace body 12, and a first discharge box 13. The two ends of the first rotary furnace body 12 are dynamically sealed to the first feed box 11 and the first discharge box 13, respectively. The decomposition chamber is formed by the first feed box 11, the first rotary furnace body 12, and the first discharge box 13. The first air outlet 131 is located at the top of the first discharge box 13, the first discharge outlet 132 is located at the bottom of the first discharge box 13, and the first feed inlet 111 and the second feed inlet 112 are both located on the first feed box 11.

[0045] During use, when the material undergoes decomposition and gasification reactions in the decomposition furnace 1, the continuous tumbling action of the first rotary furnace body 12 helps to ensure sufficient contact between the material and the high-temperature flue gas, effectively improving the reaction efficiency.

[0046] In some embodiments of the present invention, such as Figure 1 As shown, the cement production system based on biomass co-pyrolysis also includes a feeding device 5 and a hopper 6. One end of the feeding device 5 is connected to the hopper 6, and the other end is connected to the first feed box 11. Specifically, the combination of the hopper 6 and the feeding device 5 can better control the material entry rate mechanically, thereby more accurately controlling the amount of material fed per unit time, and thus controlling the balance between material and heat, avoiding the situation where excessive local accumulation leads to insufficient reaction degree.

[0047] Preferably, the feeding device 5 adopts a screw feeder, which facilitates the improvement of the overall sealing of the decomposition furnace 1, helps to create an oxygen-free or reducing atmosphere, and avoids affecting the coupling between the decomposition reaction and the gasification reaction inside the decomposition furnace 1.

[0048] 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.

[0049] 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.

[0050] 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 cement production system based on biomass co-pyrolysis, characterized by, include: A decomposition furnace is provided, which has a decomposition chamber. The decomposition chamber is provided with a first feed inlet, a second feed inlet, a first discharge outlet, and a first vent outlet. The decomposition furnace includes a first feed box, a first rotary furnace body, and a first discharge box. The two ends of the first rotary furnace body are dynamically sealed to the first feed box and the first discharge box, respectively. The decomposition chamber is enclosed by the first feed box, the first rotary furnace body, and the first discharge box. The first vent outlet is located at the top of the first discharge box, the first discharge outlet is located at the bottom of the first discharge box, and the first feed inlet and the second feed inlet are both located on the first feed box. A rotary kiln, wherein a calcination chamber is provided inside the rotary kiln, a flame outlet and a second discharge outlet are provided on one side of the calcination chamber, and a third feed outlet is provided on the other side. The third feed outlet is connected to the first discharge outlet, the flame outlet is connected to the first air outlet, and the second discharge outlet is connected to the second feed outlet. In this process, cement raw materials and biomass undergo a coupled reaction in the decomposition furnace. The coupled gaseous products are fully combusted in the rotary kiln, and the coupled solid products are calcined in the rotary kiln. Some of the calcined high-temperature solid products release heat in the decomposition furnace.

2. The system for cement production based on biomass co-pyrolysis according to claim 1, characterized in that, Also includes: A cooling furnace is provided, wherein a cooling chamber is provided inside the cooling furnace and the cooling chamber is connected to the second discharge port. An air inlet and an air outlet are provided on the cooling chamber, wherein cold air enters through the air inlet and cools the calcined solid product.

3. The cement production system based on biomass co-pyrolysis according to claim 2, characterized in that, The cooling furnace is a grate cooling furnace, with the air inlet located at the bottom of the grate cooling furnace and the air outlet located at the top of the grate cooling furnace.

4. The cement production system based on biomass co-pyrolysis according to claim 2, characterized in that, Also includes: A preheating furnace, the preheating furnace including an air inlet and a third discharge outlet, the air outlet being connected to the air inlet, and the third discharge outlet being connected to the first discharge outlet.

5. The biomass co-pyrolysis based cement production system according to claim 4, wherein, The preheating furnace includes a second feed box, a second rotary furnace body, and a second discharge box. The two ends of the second rotary furnace body are dynamically sealed to the second feed box and the second discharge box, respectively. The air inlet is located on the second discharge box, and the third discharge port is located on the second discharge box.

6. The cement production system based on biomass co-pyrolysis according to claim 1, characterized in that, Also includes: The feeding device and the hopper are provided, with one end of the feeding device connected to the hopper and the other end connected to the first feed box.

7. The biomass co-pyrolysis based cement production system according to claim 6, wherein, The feeding device is a screw feeder.

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