Composite hole structure dechlorination agent, preparation method and application thereof

Abstract

The application discloses a composite pore structure dechlorination agent and a preparation method and application thereof, and belongs to the technical field of catalysts, and comprises limestone 3.5-3.8 parts by mass, shell powder 1-1.2 parts by mass, magnesium carbonate 1-1.5 parts by mass, sodium bicarbonate 1.7-2.3 parts by mass, fruit shell powder 1.5-1.8 parts by mass and gamma-Al2O3 1-1.5 parts by mass. The dechlorination agent has a multi-pore composite pore structure, can adapt to high temperature of 300-1050 DEG C, and the dechlorination effect can reach more than 99.89%. The dechlorination agent can continuously provide strength, and has high strength in the whole production preparation, use and after use. The dechlorination agent can be used for targeted treatment of the special environment of bypass air release in the cement kiln collaborative treatment process, and can efficiently reduce the enrichment, skinning and corrosion of harmful substances in the cement kiln system.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, and in particular relates to a dechlorination agent with a composite pore structure, its preparation method, and its application. Background Technology

[0002] In the industrial process of co-processing solid waste in cement kilns, the sources of solid waste are wide-ranging and complex. Among these, solid waste contains both organic and inorganic chlorine sources. During the high-temperature stage of the cement kiln system, organic matter and plastics are converted into HCl and Cl2, primarily existing in the form of HCl. HCl flows into subsequent systems with the gases input from the cement kiln or is emitted into the atmosphere, polluting it. HCl entering subsequent systems accumulates, causing scaling and corrosion on pipes and equipment, affecting the normal operation and production safety of the cement kiln co-processing process. Therefore, how to efficiently remove chlorine introduced during the co-processing of solid waste in cement kilns has become one of the important research directions in this field.

[0003] In recent years, dechlorination agents have been widely used to remove harmful chlorine components from cement kiln systems during the co-processing of solid waste in cement kilns. Traditional dechlorination methods treat chlorine in the low-temperature range, which is not suitable for the medium- and high-temperature ranges of cement kiln co-processing. The removal of HCl in the high-temperature range has become a key research focus for many scholars. Significant progress has been made in the research of dechlorination agents at home and abroad, but problems such as poor dechlorination effect due to easy desorption at high temperatures and easy blockage of pores still exist. Summary of the Invention

[0004] Because cement kilns co-process solid waste carrying harmful substances such as chlorine, sulfur, alkali metals, and heavy metals can enter the next stage of equipment along with the flue gas, forming a cycle that accumulates and damages the equipment, affecting its operation; while bypass venting is a way to slow down the accumulation of harmful substances, the venting volume of bypass venting systems can reach 15,000-40,000 m³ / h. 3The exhaust system is characterized by complex composition (containing chlorine, alkali, sulfur, etc.) and exhaust temperatures reaching 1100℃. Treating harmful components in the exhaust system before they enter the next stage of equipment can prevent damage to downstream equipment. Addressing the above-mentioned operating conditions of the exhaust system, this invention provides a composite porous dechlorinating agent, its preparation method, and its application. The dechlorinating agent utilizes limestone, which is readily available and abundant in cement plants, as the matrix, shell powder as the carrier, and sodium bicarbonate, magnesium carbonate, and nutshells as active substances. A polyvinyl alcohol solution that enhances overall strength is added to prepare the composite porous dechlorinating agent. Through the decomposition of active substances, the volatilization of ethanol, and the inherent properties of activated carbon (generated during the preparation process of nutshell powder), a composite porous structure is formed, ranging from micropores to transitional pores and even through-pores. This increases the reaction time between the dechlorinating agent and HCl, improving dechlorination efficiency. The inherent alkaline properties of the material react with acidic gases such as HCl through an acid-base neutralization reaction, accelerating the dechlorination process and improving the dechlorination effect.

[0005] One of the technical solutions provided by this invention:

[0006] A composite porous dechlorination agent, by mass, comprises the following raw materials: 3.5-3.8 parts limestone, 1-1.2 parts shell powder, 1-1.5 parts magnesium carbonate, 1.7-2.3 parts sodium bicarbonate, 1.5-1.8 parts nut shell powder, and 1-1.5 parts γ-Al2O3.

[0007] The nut shell powder acts as a pore-forming agent, increasing the pore specific surface area of ​​the composite pore structure dechlorinator. The CO2 produced by the decomposition of sodium bicarbonate and magnesium carbonate connects individual pores into interconnected pores, transforming individual small pores into large pores, increasing the number of large pores, and arranging the pores in a tightly packed manner, thus orderly increasing the pore and dechlorinator's adsorption performance for chlorine.

[0008] γ-Al₂O₃ has a high specific surface area and porosity, with a specific surface area reaching 100-400 m². 2 / g, with a porosity generally between 0.3 and 0.8, the addition of γ-Al2O3 increases the specific surface area of ​​the dechlorinating agent, providing more active sites for adsorption; due to the high-temperature stability of γ-Al2O3 at 1200℃-1500℃, the dechlorinating agent with added γ-Al2O3 is more stable under high-temperature conditions; at high temperatures, γ-Al2O3 can adsorb chloride molecules, thereby achieving the purpose of dechlorination.

[0009] Preferably, the limestone, magnesium carbonate, sodium bicarbonate and γ-Al2O3 have a particle size of no more than 10 nm, and the shell powder and nut shell powder are prepared by crushing the shells and nut shells and passing them through a 120-230 mesh sieve.

[0010] Preferably, the raw materials of the composite porous dechlorination agent also include a binder, wherein the binder is a 1 wt% polyvinyl alcohol aqueous solution.

[0011] The second technical solution provided by this invention:

[0012] A method for preparing a composite porous dechlorinating agent involves mixing limestone, sodium bicarbonate, and nutshell powder to obtain a first mixture; mixing shell powder, magnesium carbonate, and γ-Al2O3 to obtain a second mixture; mixing the first and second mixtures to obtain a third mixture; adding a polyvinyl alcohol aqueous solution to the third mixture and mixing to obtain a semi-solid slurry; drying the semi-solid slurry, pulverizing and sieving it; adding an ethanol solution (25-30% v / v) to obtain a spherical dechlorinating agent; and aging, drying, and calcining the spherical dechlorinating agent at room temperature to obtain a high-efficiency composite porous dechlorinating agent.

[0013] This invention uses sodium bicarbonate and magnesium carbonate as active ingredients. The active ingredients themselves possess alkaline properties, and the acidic gas HCl readily reacts with them, thus being absorbed. Sodium bicarbonate and magnesium carbonate decompose at temperatures above 50℃ and 350℃, respectively, producing CO2 gas. The size of a single CO2 molecule is 0.3 nm, and the gas escapes, forming micropores. Through drying and calcination, the activated carbon generated from the decomposition of fruit shell powder contains macropores, mesopores, and micropores. Different pore sizes have different functions, with the adsorption of activated carbon mainly relying on micropores, which determine the adsorption capacity. Ethanol is used as a binder to mix and adhere the various raw materials. Furthermore, the molecular diameter of ethanol is approximately 0.76 nm. Due to its volatility, ethanol can form micropores in the dechlorination agent during the preparation process, thus acting as a pore-forming agent. The pores formed by CO2, activated carbon, and ethanol are of varying sizes, and the micropores easily connect to form larger pores. The wide pore size distribution provides adsorption performance for HCl gas. At the same time, due to the complexity of the pore structure, the adsorbed HCl gas is not easy to escape from the complex pore structure, increasing the reaction time between HCl gas and the dechlorination agent, making the adsorption of HCl gas more thorough, and improving the adsorption activity of the dechlorination agent.

[0014] Polyvinyl alcohol (PVA) has the following characteristics: (1) The molecular chain of PVA has extensibility and cross-linking properties: The polymer chain of PVA has a certain degree of extensibility and flexibility. Under the action of external force, PVA molecules can undergo inter-chain cross-linking to form a network structure, which improves the strength and toughness of the material; (2) Hydrogen bonds: PVA molecules can interact with each other through hydrogen bonds to form a strong and stable hydrogen bond network. This network can enhance the structural stability of the material and provide strength; (3) Crystal structure formation: PVA can form a crystal structure. The crystal structure has a more ordered and compact arrangement, which helps to improve the strength of the material. In this invention, PVA provides strength support in the low-temperature stage of dechlorination agent preparation. As the temperature rises, the calcium chloride generated by the reaction of calcium carbonate and HCl can play a role in increasing strength and provide subsequent strength support for the dechlorination agent. The dechlorination agent is prepared into spheres, and the large specific surface area of ​​the sphere increases the reaction contact area and improves the chlorine absorption efficiency.

[0015] Preferably, the mass ratio of the polyvinyl alcohol aqueous solution to the third mixture is 1:(6-9).

[0016] Excessive use of polyvinyl alcohol aqueous solution will increase the difficulty of molding, while insufficient use of polyvinyl alcohol aqueous solution will make it difficult to provide the strength to support transportation, addition, etc.

[0017] Preferably, the semi-solid slurry is dried, crushed, and passed through a 120-210 mesh sieve.

[0018] Preferably, the aging time is 2-4 hours; the drying temperature is 105°C and the drying time is 2 hours; the calcination temperature is 300-600°C and the calcination time is 4 hours.

[0019] During the aging process, the volatilization of ethanol can form micropores in the dechlorinating agent. If the aging time is too short, the ethanol will not volatilize completely, resulting in a small number of micropores. If the aging time is too long, it will increase the preparation cycle of the dechlorinating agent.

[0020] Excessive roasting temperature will increase energy consumption, while excessively low roasting temperature will reduce the carbonization degree of the fruit shells and seashells.

[0021] The third technical solution provided by this invention:

[0022] The above-mentioned composite pore structure dechlorinating agent is used to remove harmful chlorine components in cement kiln systems. The working range of the dechlorinating agent is 300℃-1050℃.

[0023] The beneficial effects of this invention are:

[0024] (1) This invention improves the pore size range of the dechlorinating agent by combining the decomposition of sodium bicarbonate and magnesium carbonate with the activated carbon properties of nutshell powder. The gas release during the decomposition of sodium bicarbonate and magnesium carbonate, combined with the high specific surface area and pore volume of activated carbon itself, makes it easy for individual pores to combine into larger pores, thereby promoting the expansion of the pore size range of the composite pore structure. The complex structure can effectively improve the adsorption activity of the dechlorinating agent. Nutshells have abundant pores, a robust structure, strong adaptability to high temperatures, and are more resistant to sintering. This invention, after crushing and sieving them, combines them with calcium carbonate to achieve a dechlorination effect of over 90%.

[0025] (2) Ethanol is added during the preparation process. When ethanol evaporates, it acts as a pore-forming agent, working together with the carbon dioxide released during the decomposition of sodium bicarbonate and magnesium carbonate to enrich the pore structure. At the same time, the addition of polyvinyl alcohol makes the strength of the prepared dechlorinating agent more stable. By selecting an appropriate calcination temperature, it is ensured that the obtained dechlorinating agent can maintain its mechanical strength, thus ensuring that the obtained dechlorinating agent has strong compressive strength and good adsorption activity. Magnesium oxide produced by the decomposition of magnesium carbonate is one of the active components. It can synergistically form a stable active component system of dechlorinating agent with calcium oxide produced by the decomposition of calcium carbonate, increasing the chemical adsorption capacity of the carrier and further improving the dechlorination performance.

[0026] (3) The dechlorination agent of the present invention has a wide range of raw material sources, low cost, and waste treatment, which provides a good basis for implementation; the dechlorination agent of the present invention has a multi-pore composite pore structure, can adapt to high temperature of 300-1050℃, and the dechlorination effect can reach more than 99.89%; the dechlorination agent of the present invention can continuously provide strength, so that it has high strength throughout the entire production preparation, use and after use; the dechlorination agent of the present invention can specifically treat the special environment of bypass venting in the cement kiln co-processing process, and effectively reduce the accumulation, scaling and corrosion of harmful substances in the cement kiln system.

[0027] (4) The preparation process of the composite pore structure dechlorination agent provided by the present invention is simple, without the need to add additional adhesives and pore-forming agents. It uses limestone stored in large quantities in cement plants, as well as waste such as shells and fruit shells, which not only saves costs but also achieves the effect of resource reuse. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating the on-site process detection of a simulated cement kiln in this invention.

[0030] Figure 2 The flowchart shows the preparation method of the composite porous dechlorinating agent obtained in Example 1.

[0031] Figure 3 This is a light micrograph of the composite porous dechlorinating agent prepared in Example 1;

[0032] Figure 4 The image shows the optical microscopy pattern of the composite porous dechlorinating agent prepared in Example 1 after three consecutive experimental simulations. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] This invention provides a composite porous dechlorination agent, which, by mass, comprises the following raw materials: 3.5-3.8 parts limestone, 1-1.2 parts shell powder, 1-1.5 parts magnesium carbonate, 1.7-2.3 parts sodium bicarbonate, 1.5-1.8 parts nut shell powder, and 1-1.5 parts γ-Al2O3.

[0039] If the particle size of the raw materials is too large, it will not be conducive to the thorough mixing of different raw materials. Therefore, in the preferred embodiment of the present invention, the particle size of limestone, magnesium carbonate, sodium bicarbonate and γ-Al2O3 is not greater than 10 nm, and the shell powder and fruit shell powder need to pass through a 120-230 mesh sieve. In the embodiment of the present invention, walnut shells are preferred.

[0040] In a preferred embodiment of the present invention, the raw materials of the composite porous dechlorination agent further include a binder, wherein the binder is a 1 wt% polyvinyl alcohol aqueous solution.

[0041] This invention also provides a method for preparing a composite porous dechlorinating agent. Limestone, sodium bicarbonate, and nutshell powder are mixed to obtain a first mixture. Shell powder, magnesium carbonate, and γ-Al₂O₃ are mixed to obtain a second mixture. The first and second mixtures are then mixed to obtain a third mixture. A polyvinyl alcohol aqueous solution is added to the third mixture and mixed to obtain a semi-solid slurry. The semi-solid slurry is dried, pulverized, and sieved. Ethanol and deionized water are added to obtain a spherical dechlorinating agent. The spherical dechlorinating agent is aged, dried, and calcined at room temperature to prepare a high-efficiency composite porous dechlorinating agent.

[0042] In a preferred embodiment of the present invention, the mass ratio of the polyvinyl alcohol aqueous solution to the third mixture is 1:(6-9).

[0043] In order to fully bind the semi-solid slurry with the adhesive (ethanol), the semi-solid slurry needs to be dried, crushed and sieved. In the preferred embodiment of the present invention, the sieve mesh size is limited to 120-210 mesh.

[0044] In a preferred embodiment of the present invention, the aging time is 2-4 hours, the drying temperature is 105°C and the drying time is 2 hours, and the calcination temperature is 300-600°C and the calcination time is 4 hours.

[0045] This invention also provides the application of the above-mentioned composite pore structure dechlorinating agent in removing harmful chlorine components from a cement kiln system, wherein the working range of the dechlorinating agent is 300℃-1050℃.

[0046] In this invention, the dechlorination effect is calculated using a laboratory simulation of the cement kiln co-process. The detection method is as follows, and the detection flowchart is shown below. Figure 1 .

[0047] The dechlorinating agent with a composite pore structure is placed in a programmable tubular furnace. An air cylinder and an HCl cylinder are introduced into the front end, and an alkaline absorption bottle is connected to the rear end to absorb HCl. The flow rates of air and HCl are controlled at 50 mL / min and 40 mL / min, respectively, the pressure is 0.5 kPa, the heating rate of the tubular furnace is set at 10 °C / min, and the temperature range is 300–1050 °C.

[0048] The experimental products were analyzed and determined according to GB11896-89 "Determination of Chloride in Water - Silver Nitrate Titration Method". This determination included the determination of chlorine content in the dechlorinating agent and the determination of chlorine in the alkaline absorption solution.

[0049] Determination of chloride content in dechlorinating agent: The dechlorinating agent under simulated conditions was ground into powder in a mortar and then dissolved in distilled water to prepare a suspension. The suspension was then vacuum filtered to obtain a clear solution, which was titrated according to national standards to calculate the chloride content in the dechlorinating agent as C1. The absorbent obtained under simulated conditions was directly titrated and the chloride content in the absorbent was calculated as C2.

[0050] The formula for calculating the dechlorination effect of the dechlorinating agent is:

[0051]

[0052] The room temperature in this invention refers to 25±2℃.

[0053] Example 1: A method for preparing a dechlorinating agent with a composite porous structure

[0054] S1. Crush the fruit shells and seashells separately and pass them through a 200-mesh sieve to obtain fruit shell powder and seashell powder;

[0055] S2. Mix 3.5 kg of limestone, 2 kg of sodium bicarbonate and 1.5 kg of nutshell powder evenly to obtain the first mixture;

[0056] S3. Mix 1 kg of shell powder, 0.5 kg of γ-Al2O3 and 1 kg of magnesium carbonate to obtain a second mixture;

[0057] S4. Add the first mixture and the second mixture to the tilting mixer and mix thoroughly to obtain the third mixture;

[0058] S5. Add 0.2 kg of flocculent polyvinyl alcohol to 1.98 kg of deionized water, place it in a magnetic stirrer, and dissolve it at 90°C and 30 r / min until the polyvinyl alcohol is completely dissolved to obtain a 1 wt% polyvinyl alcohol solution.

[0059] S6. Mix 9 kg of the third mixture with 1.5 kg of polyvinyl alcohol aqueous solution to form a semi-solid slurry. Dry the semi-solid slurry at room temperature and pass it through a 200-mesh sieve. Shape it into balls using a ball mixer under ethanol solution (ethanol volume 25%) spraying. Aging the mixture at room temperature for 2 hours, then drying it at 105℃ for 2 hours, and finally calcining it at 500℃ for 4 hours, yielding a composite porous dechlorinating agent. Figure 2 This is a flowchart illustrating the preparation method of a dechlorination agent with a composite porous structure. Figure 3 This is a light micrograph of the dechlorinating agent prepared in this embodiment. Figure 3 It can be seen that the pore size distribution range of the dechlorination agent prepared in this embodiment is 2-40 μm. Figure 4 The images shown are light micrographs of the dechlorinating agent prepared in this embodiment after three consecutive experimental simulations. Figure 4 It can be seen that after continuous use, the pore size distribution of the dechlorination agent prepared by this invention does not change much, and the pores are not blocked.

[0060] The working range of the composite porous dechlorinating agent prepared in this embodiment is 300℃~1050℃. The dechlorination efficiency of the dechlorinating agent prepared in this embodiment is 99.89% after testing.

[0061] Example 2: A method for preparing a dechlorinating agent with a composite porous structure

[0062] S1. Crush the fruit shells and seashells separately and pass them through a 180-mesh sieve to obtain fruit shell powder and seashell powder;

[0063] S2. Mix 3.5 kg of limestone, 2 kg of sodium bicarbonate and 1.8 kg of fruit shells evenly to obtain the first mixture;

[0064] S3. Mix 1.2 kg of seashells, 0.8 kg of γ-Al2O3 and 1 kg of magnesium carbonate to obtain a second mixture;

[0065] S4. Add the first mixture and the second mixture to the tilting mixer and mix thoroughly to obtain the third mixture;

[0066] S5. Add 0.2 kg of flocculent polyvinyl alcohol to 1.98 kg of deionized water, place it in a magnetic stirrer, and dissolve it at 90°C and 30 r / min until the polyvinyl alcohol is completely dissolved to obtain a 1 wt% polyvinyl alcohol solution.

[0067] S6. Mix 9.5 kg of the third mixture with 1.58 kg of polyvinyl alcohol aqueous solution to form a semi-solid slurry; dry the semi-solid slurry at room temperature, pass it through a 180-mesh sieve, and roll it into balls using a ball mixer under an ethanol solution (ethanol volume ratio 25%) water spray. Aging is carried out at room temperature for 2 hours, then the aged material is dried at 105°C for 2 hours and calcined at 550°C for 4 hours to obtain a composite porous dechlorinating agent. The working range of the composite porous dechlorinating agent prepared in this embodiment is: temperature 300°C~1050°C, and the dechlorination efficiency is tested to be 99.90%.

[0068] Example 3: A method for preparing a dechlorinating agent with a composite porous structure

[0069] S1. Crush the fruit shells and seashells separately and pass them through a 180-mesh sieve to obtain fruit shell powder and seashell powder;

[0070] S2. Mix 3.8 kg of limestone, 2.3 kg of sodium bicarbonate and 1.5 kg of nutshell powder evenly to obtain the first mixture;

[0071] S3. Mix 1 kg of shell powder, 1.0 kg of γ-Al2O3 and 1 kg of magnesium carbonate to obtain a second mixture;

[0072] S4. Add the first mixture and the second mixture to the tilting mixer and mix thoroughly to obtain the third mixture;

[0073] S5. Add 0.2 kg of flocculent polyvinyl alcohol to 1.98 kg of deionized water, place it in a magnetic stirrer, and dissolve it at 90°C and 30 r / min until the polyvinyl alcohol is completely dissolved to obtain a 1 wt% polyvinyl alcohol solution.

[0074] S6. Mix 9.6 kg of the third mixture with 1.6 kg of polyvinyl alcohol aqueous solution to form a semi-solid slurry; dry the semi-solid slurry at room temperature, pass it through a 180-mesh sieve, and roll it into balls using a ball mixer under an ethanol solution (ethanol volume ratio 28%) water spray. Let it age at room temperature for 3 hours, then dry the aged material at 105°C for 2 hours, and calcine it at 550°C for 4 hours to obtain a composite porous dechlorinating agent. The working range of the composite porous dechlorinating agent prepared in this embodiment is: temperature 300°C~1050°C. The dechlorination efficiency was tested to be 99.93%.

[0075] Example 4: A method for preparing a dechlorinating agent with a composite porous structure

[0076] S1. Crush the fruit shells and seashells separately and pass them through a 150-mesh sieve to obtain fruit shell powder and seashell powder;

[0077] S2. Mix 3.6 kg of limestone, 1.7 kg of sodium bicarbonate and 1.5 kg of nutshell powder evenly to obtain the first mixture;

[0078] S3. Mix 1.2 kg of shell powder, 1.1 kg of γ-Al2O3 and 1.5 kg of magnesium carbonate to obtain a second mixture;

[0079] S4. Add the first mixture and the second mixture to the tilting mixer and mix thoroughly to obtain the third mixture;

[0080] S5. Add 0.2 kg of flocculent polyvinyl alcohol to 1.98 kg of deionized water, place it in a magnetic stirrer, and dissolve it at 90°C and 30 r / min until the polyvinyl alcohol is completely dissolved to obtain a 1 wt% polyvinyl alcohol solution.

[0081] S6. Mix 9.5 kg of the third mixture with 1.12 kg of polyvinyl alcohol aqueous solution to form a semi-solid slurry; dry the semi-solid slurry at room temperature, pass it through a 150-mesh sieve, and roll it into balls using a ball mixer under an ethanol solution (ethanol volume ratio 30%) spray. Aging is carried out at room temperature for 3 hours, followed by drying at 105°C for 2 hours and calcining at 350°C for 4 hours to obtain a composite porous dechlorinating agent. The working range of the composite porous dechlorinating agent prepared in this embodiment is 300°C to 1050°C, and the dechlorination efficiency is 99.99% as tested.

[0082] Example 5: A method for preparing a dechlorinating agent with a composite porous structure

[0083] Same as Example 1, except that in S6, 9 kg of the third mixture and 1.3 kg of polyvinyl alcohol aqueous solution are mixed to form a semi-solid slurry.

[0084] Comparative Example 1

[0085] Same as Example 1, except that no fruit shell powder was added in S2.

[0086] The pore size distribution of the dechlorinating agent prepared in Comparative Example 1 was measured, and its range was 10-33 μm. The pore size distribution range of the dechlorinating agent prepared in this comparative example was significantly narrower than that of Example 1 (pore size distribution range of 5-40 μm).

[0087] The working range of the dechlorinating agent prepared in Comparative Example 1 was set to a temperature range of 300℃ to 1050℃. The dechlorination efficiency was tested to be 56.3%.

[0088] Comparative Example 2

[0089] Same as Example 1, except that sodium bicarbonate was not added in S2.

[0090] The pore size distribution of the dechlorinating agent prepared in Comparative Example 2 was measured, and its range was 5-22 μm. The pore size distribution range of the dechlorinating agent prepared in this comparative example was significantly narrower than that of Example 1 (pore size distribution range of 5-40 μm).

[0091] The working range of the dechlorinating agent prepared in Comparative Example 2 was set to a temperature of 300℃~1050℃. The dechlorination efficiency was tested to be 65.4%.

[0092] Comparative Example 3

[0093] Same as Example 1, except that magnesium carbonate was not added in S3.

[0094] The pore size distribution of the dechlorinating agent prepared in Comparative Example 3 was measured, and its range was 7-20 μm. The pore size distribution range of the dechlorinating agent prepared in this comparative example was significantly narrower than that of Example 1 (pore size distribution range of 5-40 μm).

[0095] The dechlorination agent prepared in this comparative example was set to operate within a temperature range of 300℃ to 1050℃. After testing, the dechlorination efficiency was found to be 67.2%.

[0096] Comparative Example 4

[0097] Same as Example 1, except that in S6, the sample is calcined at 250°C for 4 hours.

[0098] The working range of the dechlorinating agent prepared in this comparative example was set to a temperature of 300℃~1050℃. After testing, the dechlorination efficiency was 83.3%.

[0099] Comparative Example 5

[0100] Same as Example 1, except that in S6, the sample is calcined at 700°C for 4 hours.

[0101] The working range of the dechlorinating agent prepared in this comparative example was set to a temperature of 300℃~1050℃. After testing, the dechlorination efficiency was 85.1%.

[0102] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. The application of a composite porous dechlorinating agent in removing harmful chlorine components from a cement kiln system, characterized in that, The working range of the composite porous structure dechlorinating agent is 300℃~1050℃; The composite porous dechlorination agent comprises, by weight, the following raw materials: 3.5-3.8 parts limestone, 1-1.2 parts shell powder, 1-1.5 parts magnesium carbonate, 1.7-2.3 parts sodium bicarbonate, 1.5-1.8 parts nutshell powder, and 1-1.5 parts γ-Al2O3; The preparation method of the composite porous dechlorination agent includes the following steps: mixing limestone, sodium bicarbonate and nutshell powder to obtain a first mixture; mixing shell powder, magnesium carbonate and γ-Al2O3 to obtain a second mixture; mixing the first mixture and the second mixture to obtain a third mixture; adding polyvinyl alcohol aqueous solution to the third mixture and mixing to obtain a semi-solid slurry; drying the semi-solid slurry, pulverizing and sieving it; adding ethanol solution to obtain a spherical dechlorination agent; aging, drying and calcining the spherical dechlorination agent at room temperature to prepare a high-efficiency dechlorination agent with a composite porous structure. The limestone, magnesium carbonate, sodium bicarbonate, and γ-Al2O3 all have a particle size of no more than 10 nm; the shell powder and nut shell powder are prepared by crushing the shells and nut shells and passing them through a 120-230 mesh sieve. The raw materials of the composite porous dechlorination agent also include a binder, which is a 1 wt% polyvinyl alcohol aqueous solution; The mass ratio of the polyvinyl alcohol aqueous solution to the third mixture is 1:(6-9); The aging time is 2-4 hours; The roasting temperature is 300-600℃ and the roasting time is 4 hours.

2. The application according to claim 1, characterized in that, The semi-solid slurry is dried, crushed, and passed through a 120-210 mesh sieve.

3. The application according to claim 1, characterized in that, The drying temperature is 105℃ and the drying time is 2 hours.

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