Preparation method of all-solid-waste light negative carbon building block

Abstract

The invention belongs to the technical field of building materials, and particularly relates to a preparation method of an all-solid-waste light negative carbon building block. The method comprises the following steps: 1, arranging equipment comprising a building block carbonization unit; and 2, building block forming is conducted in the building block containing cavity. And 3, replacing the solid partition plate with a porous partition plate to complete the assembly of the carbonization structure in the block carbonization unit. And step 4, introducing a gas containing carbon dioxide, exhausting the gas through an induced draft fan, and forming an air pressure gradient between the positive pressure region and the negative pressure region to realize carbonization of the carbon dioxide through the building block. According to the method, by forming air pressure gradient ventilation and mechanical pressure gradient, carbon dioxide directionally flows and penetrates through the formed building block, and compared with a traditional carbonization curing method, the method is higher in carbonization curing speed, higher in carbonization degree and shorter in carbonization time.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and specifically relates to a method for preparing all-solid waste lightweight negative carbon building blocks. Background Art

[0002] Carbonization enhancement of lightweight solid waste-based blocks can increase the strength of the blocks. Therefore, when producing similar block materials in the prior art, the blocks are placed in a carbon dioxide carbonization device after demoulding and carbonized with carbon dioxide gas. However, conventional carbonization equipment mainly improves the carbonization efficiency by adding high-temperature and high-pressure carbon dioxide gas, which has high requirements for the pressure-maintaining safety performance of the equipment. At the same time, since the blocks are evenly pressurized on all sides in the equipment, the effect of increasing the air pressure is to increase the dissolution rate of carbon dioxide in water by increasing the volume concentration of carbon dioxide, but it does not help to accelerate the penetration of gas into the interior of the blocks. In addition, water will be produced during the carbonization reaction. When a closed carbonization device is used, excess water will remain inside the blocks, further hindering the penetration of carbon dioxide gas. However, raising the temperature outside the blocks to allow the water vapor to completely evaporate requires a higher temperature, and the evaporated water vapor cannot be quickly taken away, so it is not effective in improving the efficiency of the carbonization reaction. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing all-solid waste lightweight negative carbon building blocks, which is used to solve the technical problem in the prior art that due to the uniform pressure on the four sides of the blocks, the carbon dioxide gas diffuses slowly into the interior of the blocks and generates water vapor, which is difficult to be quickly carried away in this environment, further reducing the carbonization efficiency.

[0004] The method for preparing all-solid waste lightweight negative carbon building blocks comprises the following steps.

[0005] Step 1: Set up the equipment including the building block carbonization unit.

[0006] Step 2: forming blocks in the block accommodating cavity.

[0007] Step 3: Replace the solid partition with a porous partition to complete the assembly of the carbonization structure in the building block carbonization unit.

[0008] Step 4: introducing gas containing carbon dioxide and exhausting it through an induced draft fan to form a pressure gradient between the positive pressure zone and the negative pressure zone, so that carbon dioxide can be carbonized through the building blocks, and a mechanical pressure gradient is applied to the building blocks through a pressing head.

[0009] Preferably, the block carbonization unit includes a shell, pressing heads symmetrically slidably arranged on both sides of the shell in the horizontal direction, and upper and lower partitions horizontally installed in the shell, a block accommodating cavity is formed between the two partitions, the inner cavity portion of the shell above the upper partition is a positive pressure zone, and the inner cavity portion of the shell below the lower partition is a negative pressure zone; the partitions are divided into two types according to the needs of different steps, one is a solid partition, and the other is a porous partition, and the porous partitions are provided with through holes connected to the block accommodating cavity.

[0010] Preferably, in step 2, the lower solid partition is first fixedly installed in the shell, the lower side of the pressing head is fitted with the lower solid partition, steel slag, waste concrete, biomass charcoal, solid waste lightweight aggregate and water are uniformly mixed and poured into the block accommodating cavity, and then the upper solid partition is installed, and a pressing mechanism is formed by the solid partition, the pressing head and the shell to preliminarily press the material into shape. During the pressing process, the pressing head applies a pressure of 5-60MPa to the material.

[0011] Preferably, in step three, the pressing head is kept stationary to clamp the formed building blocks, and then the solid partition is removed and replaced with a porous partition, the porous partition is fixedly installed in the shell, the negative pressure zone is closed and connected to the induced draft fan that generates negative pressure through pipeline two, the positive pressure zone is closed and connected to the equipment for inputting carbon dioxide gas through pipeline one, and the assembly of the carbonization structure in the building block carbonization unit is completed.

[0012] Preferably, in step 4, a gas containing carbon dioxide is introduced into the top of the positive pressure zone through pipeline 1 to ensure a certain positive pressure effect, and the gas pressure range of the positive pressure zone is 0.5-5MPa. The gas introduced into the positive pressure zone is cement kiln flue gas; in this step, the pressing head still needs to maintain a certain pressure, and the pressure applied by the pressing head is in the range of 5-60MPa.

[0013] Preferably, in step 4, the flue gas introduced is divided into three categories, the first category of flue gas has a relative humidity range of more than 90% and a temperature range of 50-100°C; the second category of flue gas has a relative humidity range of 20-50% and a temperature range of 100-200°C; the third category of flue gas has a relative humidity range of 50-80% and a temperature range of 70-120°C; initially, the first category of flue gas is introduced into the positive pressure zone, and when the pressure gradually increases to a certain value, different cement kiln flue gases are deployed to reduce the humidity of the flue gas, and the second category of flue gas is introduced into the positive pressure zone instead, and when the pressure in the positive pressure zone is reduced to a certain value, the introduction of the first category of flue gas is resumed, and this is repeated until the carbon dioxide concentration in the negative pressure zone begins to increase; when the carbon dioxide concentration in the negative pressure zone begins to increase, the introduced flue gas is replaced by the third category of flue gas and introduced into the positive pressure zone, and the air pressure in the positive pressure zone is gradually increased, and the air pressure in the positive pressure zone is stopped after reaching a certain value.

[0014] Preferably, the flue gas introduced is obtained by mixing the flue gas and air from different sections of the cement kiln. The flue gas from different sections includes any one or more combinations of the flue gas after desulfurization at the tail of the cement kiln, the flue gas after raw material grinding, the flue gas after denitrification of the cement kiln, and the flue gas at the top of the cement kiln preheater. The flue gas from different sections has different temperatures and relative humidities, but the carbon dioxide concentration is consistent.

[0015] Preferably, there are several building block carbonization units, and according to the required size of the building blocks, several building block carbonization units are stacked up and down and connected in series to form a group of building block carbonization equipment, the negative pressure zone of the lowest building block carbonization unit is connected to the induced draft fan and generates negative pressure after the induced draft fan is running, while the positive pressure zone of the uppermost building block carbonization unit is filled with flue gas containing carbon dioxide to form a certain positive pressure, and the adjacent positive pressure zones and negative pressure zones between each building block accommodating cavity are connected to form an intermediate ventilation zone.

[0016] The present invention has the following advantages: the present invention forms an air pressure gradient ventilation mode, so that carbon dioxide can flow directionally through the formed blocks, which is faster, has a higher carbonization degree and a shorter carbonization time than traditional carbonization curing.

[0017] The carbonization process of solid waste-based building blocks uses flue gas from different sections of the cement kiln tail, and obtains the required gas with different humidity and temperature by mixing gas and spraying water for humidification. The carbonization process of solid waste-based building blocks will also fix a large amount of carbon dioxide, which is beneficial for cement plants to reduce carbon emissions. Solid waste-based building blocks can react with sulfur oxides and nitrogen oxides in flue gas to reduce the pressure of desulfurization and denitrification of cement plant tail gas. By controlling the temperature and humidity of the gas, it is possible to take away the excess moisture produced by the carbonization reaction while maintaining a certain amount of moisture, ensuring a high efficiency of the carbonization reaction and improving the degree of carbonization reaction.

[0018] Multiple carbonization units are connected in series, and the upper layer is removed after the carbonization treatment is completed, and the lower layer is moved to the upper layer. This ensures that the solid waste-based building blocks are initially carbonized at a lower carbon dioxide concentration to avoid the products generated by the violent carbonization reaction on the surface hindering the subsequent carbonization reaction. After the reaction reaches a certain degree, it is exposed to a high carbon dioxide concentration to fully carbonize the entire building block, achieve a higher degree of carbonization, and effectively increase the strength.

[0019] From the material perspective, the present invention uses a variety of solid waste materials to prepare negative carbon building materials, among which biochar permanently fixes carbon dioxide in the air and has the characteristics of being light, porous and breathable. Solid waste-based lightweight aggregates such as ceramsite also have a certain degree of air permeability, which is conducive to the transmission of carbon dioxide gas during the carbonization process. Lightweight solid waste-based blocks are reinforced by carbonization, and the carbonization products are mainly calcium carbonate, silica gel, etc., which can fill pores and protect the outer surface, thereby increasing the strength of the blocks and optimizing the durability of the blocks. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the block carbonization unit in the method for preparing all-solid waste lightweight negative carbon building blocks of the present invention.

[0021] Figure 2 for Figure 1 Right side view of the structure shown.

[0022] Figure 3 for Figure 2 The structure shown is a cross-sectional view along the AA direction in step 2.

[0023] Figure 4 for Figure 2 The structure shown is a cross-sectional view along the AA direction in steps three and four.

[0024] The reference numerals in the accompanying drawings include: 1. shell, 2. pressing head, 3. positive pressure zone, 4. pipeline one, 5. negative pressure zone, 6. pipeline two, 7. solid partition, 8. building block, 9. porous partition. DETAILED DESCRIPTION

[0025] The specific implementation modes of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0026] like Figure 1-Figure 4 As shown, the present invention provides a method for preparing all-solid waste lightweight negative carbon building blocks, comprising the following steps.

[0027] Step 1: Set up the equipment including the building block carbonization unit.

[0028] The block carbonization unit includes a shell 1, a material pressing head 2 symmetrically slidably arranged on both sides of the shell 1 in the horizontal direction, and an upper and lower partition plate horizontally installed in the shell 1, a block accommodating cavity is formed between the two partition plates, the inner cavity portion of the shell 1 above the upper partition plate is a positive pressure zone 3, and the inner cavity portion of the shell 1 below the lower partition plate is a negative pressure zone 5; the partition plates are divided into two types according to the needs of different steps, one is a solid partition plate 7, and the other is a porous partition plate 9, and the porous partition plates 9 are provided with through holes connected to the block accommodating cavity.

[0029] Step 2: forming the building block 8 in the building block accommodating cavity.

[0030] In this step, the lower solid partition 7 is first fixedly installed in the shell 1, and the lower side of the pressing head 2 is fitted with the lower solid partition 7, and the steel slag, waste concrete, biomass charcoal, solid waste lightweight aggregate and water are uniformly mixed and poured into the block accommodating cavity, and then the upper solid partition 7 is installed, and a pressing mechanism is formed by the solid partition 7, the pressing head 2 and the shell 1 to preliminarily press the material into shape. During the pressing process, the pressing head 2 applies a pressure of 5-60MPa to the material.

[0031] Step 3: Replace the solid partition 7 with the porous partition 9 to complete the assembly of the carbonization structure in the building block carbonization unit.

[0032] In this step, the pressing head 2 is kept stationary to clamp the formed building block 8, and then the solid partition 7 is removed and replaced with a porous partition 9, and the porous partition 9 is fixedly installed in the shell 1, the negative pressure zone 5 is closed and connected to the induced draft fan that generates negative pressure through the pipeline 2 6, and the positive pressure zone 3 is closed and connected to the equipment for inputting carbon dioxide gas through the pipeline 1 4, thereby completing the assembly of the carbonization structure in the building block carbonization unit.

[0033] Step 4: introducing gas containing carbon dioxide and exhausting it through an induced draft fan to form a pressure gradient between the positive pressure zone 3 and the negative pressure zone 5, so that carbon dioxide can be carbonized through the building blocks 8, and a mechanical pressure gradient is applied to the building blocks through the pressing head.

[0034] A gas containing carbon dioxide is introduced into the top of the positive pressure zone 3 through a pipeline 1-4 to ensure a certain positive pressure effect. The air pressure range of the positive pressure zone 3 is 0.5-5MPa. The gas introduced into the positive pressure zone 3 is cement kiln flue gas. This method can control and adjust the temperature and humidity of the gas by taking cement kiln flue gas from different sections, such as different flue gases before entering the raw mill, after dust collection at the kiln tail, and after desulfurization. It should be noted that in this step, the pressure head 2 still needs to maintain a certain pressure and gradually increase the pressure during the carbonization process. The pressure applied by the pressure head 2 is in the range of 5-60MPa, that is, a mechanical pressure gradient is applied.

[0035] In this step, the cement kiln flue gas flows continuously from the positive pressure zone 3 to the negative pressure zone 5 through the light solid waste blocks 8 under the pressure gradient. In the process of the cement kiln flue gas passing through the light solid waste blocks 8, the carbon dioxide in the flue gas continuously reacts with the solid waste blocks 8 to increase the strength of the blocks 8. In this process, the carbon dioxide gas is simultaneously subjected to the positive pressure of the positive pressure zone 3 and the negative pressure of the negative pressure zone 5. The penetration rate of carbon dioxide in the blocks 8 is faster than that in the case of uniformly applying positive pressure around the blocks 8, and it has a clear flow direction and an increased flow rate, which can avoid the defect of slow diffusion of carbon dioxide in a static environment.

[0036] Since the carbonization reaction produces moisture, it will make it more difficult for gas to pass through the lightweight building block 8. Therefore, in the building block carbonization unit, the positive pressure zone 3 is provided with a gas pressure test sensor and a humidity sensor. According to the characteristics of the flue gas used and the need for evaporation of water vapor in the building block carbonization unit, the flue gas introduced in this scheme is divided into two categories. The first category is flue gas with high humidity and temperature below 100°C, which is used for conventional carbonization needs. The second category is flue gas with low humidity and temperature not lower than 100°C, which is used for carbonization and evaporation to take away water vapor at the same time.

[0037] Initially, the first type of flue gas (humidity range of more than 90%, temperature range of 50-100°C) is introduced into the positive pressure zone 3. When the pressure gradually increases to a certain value, different cement kiln flue gases are deployed to reduce the humidity of the flue gas, and the second type of flue gas (humidity range of 20-50%, temperature range of 100-200°C) is introduced into the positive pressure zone 3 instead. When the pressure in the positive pressure zone 3 is reduced to a certain value, the first type of flue gas is restored, and this is repeated until the carbon dioxide concentration in the negative pressure zone 5 begins to increase. In addition, the method can also be set to introduce a third type of flue gas (relative humidity range of 50-80%, temperature range of 70-120°C) into the positive pressure zone 3. When the carbon dioxide concentration in the negative pressure zone 5 begins to increase, the introduced flue gas is replaced by the third type of flue gas, the flue gas humidity is increased, and a higher temperature is maintained, so as to improve the carbonization efficiency at the end of the carbonization reaction. When the carbonization reaction is completed, the air pressure in the positive pressure zone 3 reaches a certain value and then stops.

[0038] After the carbonization structure is assembled, the carbonization unit can be charged with carbon dioxide-containing gas to carbonize a single block 8, or a group of carbonization equipment of blocks 8 formed by stacking several carbonization units in series can be formed to achieve the effect of carbonizing multiple blocks 8 at the same time. When doing so, for the several carbonization units of the blocks stacked together, the negative pressure zone 5 of the carbonization unit of the lowest block is connected to the induced draft fan and generates negative pressure after the induced draft fan is running, while the positive pressure zone 3 of the carbonization unit of the highest block is charged with flue gas containing carbon dioxide and forms a certain positive pressure, and the adjacent positive pressure zones 3 and negative pressure zones 5 between the accommodating chambers of each block are connected to form an intermediate ventilation zone, thereby achieving the simultaneous carbonization of multiple blocks 8, and the carbonization efficiency of the blocks 8 at the bottom is relatively low. Therefore, for such equipment with multiple carbonization units stacked together, the carbonization units of the blocks initially placed in the lower layer can move the blocks 8 of the lower layer to the upper layer after the blocks 8 react to a certain degree, and re-introduce carbon dioxide-containing gas for carbonization.

[0039] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the inventive concept and technical solution of the present invention, or the inventive concept and technical solution are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for preparing all-solid waste lightweight negative carbon building blocks, characterized in that: The following steps are involved: Step 1, setting up equipment including a building block carbonization unit; Step 2: forming a building block (8) in the building block accommodating cavity; Step 3: Replace the solid partition (7) with a porous partition (9) to complete the assembly of the carbonization structure in the building block carbonization unit; Step 4: introducing a gas containing carbon dioxide and exhausting the gas through an induced draft fan to form a pressure gradient between the positive pressure zone (3) and the negative pressure zone (5), thereby achieving carbonization of the carbon dioxide through the building blocks (8).

2. The method for preparing the all-solid waste lightweight negative carbon building block (8) according to claim 1, characterized in that: The block carbonization unit comprises a shell (1), a material pressing head (2) symmetrically slidably arranged on both sides of the shell (1) in the horizontal direction, and an upper and lower partition plate installed horizontally in the shell (1); a block accommodating cavity is formed between the two partition plates; the inner cavity portion of the shell (1) above the upper partition plate is a positive pressure zone (3), and the inner cavity portion of the shell (1) below the lower partition plate is a negative pressure zone (5); the partition plates are divided into two types according to the needs of different steps, one is a solid partition plate (7), and the other is a porous partition plate (9); the porous partition plates (9) are provided with through holes connected to the block accommodating cavity.

3. The method for preparing the all-solid waste lightweight negative carbon building block (8) according to claim 1, characterized in that: In the step 2, the lower solid partition (7) is first fixedly installed in the shell (1), the lower side of the pressing head (2) is fitted with the lower solid partition (7), steel slag, waste concrete, biomass charcoal, solid waste lightweight aggregate and water are uniformly mixed and poured into the block accommodating cavity, and then the upper solid partition (7) is installed. A pressing mechanism is formed by the solid partition (7), the pressing head (2) and the shell (1), and the material is initially pressed into shape; during the pressing process, the pressing head (2) applies a pressure of 5-60MPa to the material, and the thickness of the block pressed between the two solid partitions is 10-50cm.

4. The method for preparing the all-solid waste lightweight negative carbon building block (8) according to claim 1, characterized in that: In the step three, the pressing head (2) is kept stationary to clamp the formed building block (8), then the solid partition (7) is removed, and the solid partition (7) is replaced by a porous partition (9), and the porous partition (9) is fixedly installed in the shell (1), the negative pressure zone (5) is closed and connected to the induced draft fan that generates negative pressure through the pipeline two (6), and the positive pressure zone (3) is closed and connected to the device for inputting carbon dioxide gas through the pipeline one (4), thereby completing the assembly of the carbonization structure in the building block carbonization unit.

5. The method for preparing the all-solid waste lightweight negative carbon building block (8) according to claim 1, characterized in that: In the step 4, a gas containing carbon dioxide is introduced into the top of the positive pressure zone (3) through the pipeline 1 (4) to ensure a certain positive pressure effect, and the air pressure range of the positive pressure zone (3) is 0.5-5MPa; the gas introduced into the positive pressure zone (3) is cement kiln flue gas; in this step, the pressing head (2) still needs to maintain a certain pressure, and the pressure applied by the pressing head (2) is in the range of 5-60MPa.

6. The method for preparing the all-solid waste lightweight negative carbon building block (8) according to claim 1, characterized in that: In the step 4, the flue gas introduced is divided into three categories, the first category of flue gas has a relative humidity range of more than 90% and a temperature range of 50-100°C; the second category of flue gas has a relative humidity range of 20-50% and a temperature range of 100-200°C; the third category of flue gas has a relative humidity range of 50-80% and a temperature range of 70-120°C; initially, the first category of flue gas is introduced into the positive pressure zone (3); when the pressure gradually increases to a certain value, different cement kiln flue gases are adjusted to reduce the humidity of the flue gas, and the second category of flue gas is introduced into the positive pressure zone (3) instead; when the pressure in the positive pressure zone (3) decreases to a certain value, the first category of flue gas is resumed, and this process is repeated until the carbon dioxide concentration in the negative pressure zone (5) begins to increase; when the carbon dioxide concentration in the negative pressure zone (5) begins to increase, the introduced flue gas is replaced by the third category of flue gas and introduced into the positive pressure zone (3), and the air pressure in the positive pressure zone is gradually increased, and the air pressure in the positive pressure zone (3) is stopped after reaching 4-5MPa.

7. The method for preparing the all-solid waste lightweight negative carbon building block (8) according to claim 6, characterized in that: The flue gas introduced is obtained by mixing the flue gas and air from different sections of the cement kiln. The flue gas from different sections includes any one or more combinations of the flue gas after desulfurization at the tail of the cement kiln, the flue gas after raw material grinding, the flue gas after denitrification of the cement kiln, and the flue gas at the top of the cement kiln preheater. The flue gas from different sections has different temperatures and relative humidity, but the carbon dioxide concentration is the same.

8. The method for preparing the all-solid waste lightweight negative carbon building block (8) according to claim 7, characterized in that: There are a plurality of building block carbonization units. According to the required building block size, a plurality of building block carbonization units are stacked up and down and connected in series to form a group of building block (8) carbonization equipment. The negative pressure zone (5) of the lowest building block carbonization unit is connected to an induced draft fan and generates negative pressure after the induced draft fan is running, while the positive pressure zone (3) of the highest building block carbonization unit is filled with flue gas containing carbon dioxide to form a certain positive pressure, and the adjacent positive pressure zones (3) and negative pressure zones (5) between the building block accommodating cavities are connected to form an intermediate ventilation zone.

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