Preparation method and application of liquid-phase low-temperature composite dechlorinating agent

Abstract

The invention relates to the technical field of catalysts, in particular to a preparation method and application of a liquid-phase low-temperature composite dechlorinating agent, and the liquid-phase low-temperature composite dechlorinating agent comprises the following components in percentage by mass: 8%-32% of CaO, 5%-25% of NaO, 12%-18% of ZnO, 8%-55% of aluminum oxide, 0.1%-2% of iron and 0.1%-2% of manganese. According to the invention, the dechlorination capability is greatly improved, the CaO content is adjusted to enhance the chlorine holding capability, and the dechlorination precision is improved; naO can better adapt to working conditions with different water contents, and stable dechlorination in a complex liquid phase environment is ensured; the alkaline environment is optimized by ZnO, efficient dechlorination reaction is promoted, the dechlorinating agent is stable in structure and not prone to hardening due to the reasonable component proportion and the well-designed preparation technology, parameters of all steps in the preparation process are accurately controlled, and it is ensured that the performance of the dechlorinating agent is stable.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and specifically to a preparation method and application of a liquid-phase low-temperature composite dechlorinating agent. Background Art

[0002] In industries such as petroleum refining and fine chemicals, chlorides in raw materials or reaction products can have a serious impact on subsequent processes and equipment. During the petroleum processing, organic and inorganic chlorides in crude oil, chlorine-containing additives added during extraction and transportation, and chlorides introduced during catalytic reforming will, in subsequent liquid-phase reactions or distillation processes, corrode equipment, cause catalyst poisoning and inactivation, and affect product quality and production stability. For example, in some fine chemical productions with high requirements for equipment materials, the presence of chlorides will significantly increase the corrosion rate of equipment, shorten the service life of equipment, and increase production costs; in reactions such as catalytic hydrogenation, chlorides will adsorb on the catalyst surface, occupy active sites, and reduce the activity and selectivity of the catalyst.

[0003] Existing dechlorination technologies have many deficiencies when dealing with liquid-phase materials. Traditional high-temperature dechlorination methods require a large amount of energy, have high requirements for equipment, and may cause side reactions such as decomposition or polymerization of materials at high temperatures, affecting product quality; some room-temperature dechlorinating agents have low dechlorination accuracy and weak chlorine-holding ability in a low-temperature (0 - 60°C) liquid-phase environment, unable to meet production requirements; some dechlorinating agents are prone to caking during use, resulting in an increase in bed resistance and the need for frequent replacement, increasing the complexity and cost of production. Therefore, a preparation method and application of a liquid-phase low-temperature composite dechlorinating agent are proposed. Summary of the Invention

[0004] In view of this, the present invention provides a preparation method and application of a liquid-phase low-temperature composite dechlorinating agent to solve or alleviate the technical problems existing in the prior art and provide at least one beneficial option.

[0005] The technical solution of the present invention is realized as follows: A preparation method of a liquid-phase low-temperature composite dechlorinating agent comprises components with the following mass percentages: 8% - 32% of CaO, 5% - 25% of NaO, 12% - 18% of ZnO, 8% - 55% of alumina, 0.1% - 2% of iron, and 0.1% - 2% of manganese.

[0006] Further preferably, it includes the following steps:

[0007] S1. Prepare a carrier;

[0008] S2. Shape, dry, and calcine;

[0009] S3. Load the second main active component;

[0010] S4. Subsequent treatment.

[0011] More preferably, in the S1, the first main active component (calcium hydroxide or / and calcium carbonate), the co-active component (zinc oxide or / and zinc carbonate), the auxiliary materials (powder carrier and pore-forming agent), and the binder (one or two of attapulgite, bentonite, and carboxymethyl cellulose) are mixed evenly in a certain proportion. Among them, the mass ratio of the first main active component accounts for 15%-35% of the total raw material mass, the co-active component accounts for 8%-22%, the powder carrier (aluminum oxide powder or / and molecular sieve powder) accounts for 25%-55%, the pore-forming agent (ammonium bicarbonate or / and powdered activated carbon powder) accounts for 6%-18%, and the binder accounts for 6%-12%. A mixer is used to stir thoroughly to make them evenly mixed.

[0012] More preferably, in the S2, the mixed materials are made into a specific shape through an extrusion or rolling ball forming process. After forming, it is dried at a temperature of 110°C - 120°C for 2 - 3 hours to remove moisture. Then, it is heated at a heating rate of 3°C / min - 8°C / min to 440°C - 460°C and calcined for 2 - 3 hours to cause physical and chemical changes in the materials, forming a carrier with a certain strength and pore structure.

[0013] More preferably, in the S3, the second main active component (one or two of sodium hydroxide, sodium carbonate, and sodium bicarbonate) is dissolved in an appropriate amount of water to prepare an impregnating solution. The mass of the second main active component is 8%-22% of the carrier mass. The prepared carrier and the impregnating solution are stirred and mixed, and the stirring speed is controlled at 150 - 250 revolutions per minute, and the mixing time is 40 - 50 minutes. Then, it is left standing for 1.2 - 1.8 hours to allow the second main active component to be fully loaded into the pores of the carrier.

[0014] More preferably, in the S4, after the standing ends, the excess impregnating solution is removed by filtration. The carrier loaded with the second main active component is dried at a temperature of 95°C - 115°C for 2 - 3 hours to further remove moisture. Finally, it is heated at a heating rate of 3°C / min - 8°C / min to 330°C - 390°C and calcined for 2 - 3 hours to make the second main active component better combined with the carrier, thus obtaining a liquid-phase low-temperature composite dechlorination agent.

[0015] A preparation method and application of a liquid-phase low-temperature composite dechlorination agent. The liquid-phase low-temperature composite dechlorination agent is applicable to removing chlorides from various liquid-phase materials, such as the liquid-phase product after reforming reaction, raw materials or intermediate products in fine chemical production, etc., under the pressure conditions of 0 - 60°C and 0 - 3 MPa. In actual application, the dechlorination agent is filled in a fixed-bed reactor or other suitable reaction devices, and the liquid-phase material passes through the dechlorination agent bed layer at an airspeed of less than 3000 h -1 to achieve efficient removal of chlorides.

[0016] Due to the above technical solutions adopted in the embodiments of the present invention, it has the following advantages:

[0017] 1. The dechlorination ability of the present invention is greatly improved. The adjustment of the CaO content enhances the chlorine-holding ability and improves the dechlorination accuracy; NaO better adapts to different water content conditions to ensure stable dechlorination in a complex liquid phase environment; ZnO optimizes the alkaline environment to promote the efficient progress of the dechlorination reaction. The reasonable component ratio and the carefully designed preparation process make the dechlorination agent have a stable structure and is not prone to caking. The parameters of each step in the preparation process are accurately controlled to ensure the stable performance of the dechlorination agent.

[0018] 2. Compared with the traditional high-temperature dechlorination method, this dechlorination agent can efficiently dechlorinate at low temperatures, avoiding side reactions of materials caused by high temperatures, reducing energy consumption, and lowering equipment requirements, thus saving energy and reducing adverse effects on product quality.

[0019] 3. Trace elements such as iron and manganese added in the present invention are used as catalyst assistants to further enhance the activity and selectivity of the dechlorination agent. By adjusting the types and contents of trace elements, the dechlorination agent can be customized according to different industrial needs to meet more complex and higher requirements for dechlorination scenarios in the future, enhancing the competitiveness of the product.

[0020] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present invention will become apparent by reference to the drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is the method flow structure diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present invention. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0024] The embodiments of the present invention will be described in detail below with reference to the drawings.

[0025] Example 1. Preparation of dechlorination agent: Weigh 20 kg of calcium hydroxide, 15 kg of zinc oxide, 50 kg of activated alumina, 10 kg of ammonium bicarbonate, and 8 kg of attapulgite. Mix these materials thoroughly in a mixer. Use an extrusion molding process to make strip-shaped materials with a diameter of 3 - 4 mm. Dry them at 115 °C for 2.5 hours, heat them to 450 °C at a heating rate of 5 °C / min, and calcine for 2.5 hours to obtain a carrier. Dissolve 12 kg of sodium hydroxide in an appropriate amount of water to prepare an impregnation solution, stir and mix it with 50 kg of the above carrier at a stirring speed of 200 revolutions per minute for 45 minutes, and let it stand for 1.5 hours. After filtration, dry it at 105 °C for 2.5 hours, heat it to 360 °C at a heating rate of 5 °C / min, and calcine for 2.5 hours to prepare a liquid-phase low-temperature composite dechlorination agent. After testing, the content of CaO in this dechlorination agent is 15%, the content of NaO is 18%, the content of ZnO is 15%, the alumina content is 40%, and 0.5 kg of iron element (mass percentage content is about 0.7%) is added. Application test: Load 3 mL of this dechlorination agent in a fixed-bed reactor with a reactor diameter of 8 mm. Fill 2 mL of quartz sand with a mesh size of 10 - 20 in both the upper and lower parts of the dechlorination agent. Use the liquid-phase reformate containing 300 ppm of hydrogen chloride as the raw material. Under the conditions of a temperature of 30 °C, a pressure of 1.5 MPa, and a space velocity of 2000 h -1 Perform a dechlorination test. After 600 hours of continuous operation, the content of hydrogen chloride in the outlet material is less than 3 ppm, no caking phenomenon occurs in the dechlorination agent bed layer, and the breakthrough chlorine capacity reaches 25.5%.

[0026] Example 2. Preparation of dechlorination agent: Weigh 18 kg of calcium carbonate, 12 kg of zinc carbonate, 45 kg of pseudoboehmite, 12 kg of powdered activated carbon powder, and 10 kg of bentonite. After mixing evenly, use a rolling ball molding process to make spherical materials with a particle size of 3 - 4 mm. Dry them at 120 °C for 2 hours, heat them to 440 °C at a heating rate of 6 °C / min, and calcine for 3 hours to obtain a carrier. Dissolve 10 kg of sodium carbonate in water to prepare an impregnation solution, stir and mix it with 50 kg of the carrier at a stirring speed of 180 revolutions per minute for 50 minutes, and let it stand for 1.8 hours. After filtration, dry it at 110 °C for 2 hours, heat it to 340 °C at a heating rate of 6 °C / min, and calcine for 3 hours to prepare a liquid-phase low-temperature composite dechlorination agent. After testing, the content of CaO in this dechlorination agent is 13%, the content of NaO is 15%, the content of ZnO is 12%, the alumina content is 45%, and 0.3 kg of manganese element (mass percentage content is about 0.4%) is added. Application test: In the same fixed-bed reactor, load 3 mL of this dechlorination agent. Use the fine chemical raw material containing 400 ppm of hydrogen chloride and entraining a small amount of water as the test material. Under the conditions of a temperature of 20 °C, a pressure of 2 MPa, and a space velocity of 1500 h -1Under the condition of dechlorination test, after running for 500 hours, the hydrogen chloride content in the outlet material is lower than 5 ppm, the dechlorination agent bed remains soft, no caking phenomenon occurs, and the breakthrough chlorine capacity reaches 24.2%.

[0027] Example 3. Preparation of dechlorination agent: Weigh 22 kg of a mixture of calcium hydroxide and calcium carbonate (mass ratio 1:1), 18 kg of zinc oxide, 35 kg of a mixture of activated alumina and 4A molecular sieve (mass ratio 1:1), 10 kg of a mixture of ammonium bicarbonate and powdered activated carbon powder (mass ratio 1:1), and 7 kg of hydroxymethyl cellulose. After mixing evenly, extrude into strips. Dry at 110 °C for 3 hours, heat up to 460 °C at a heating rate of 4 °C / min, and calcine for 2 hours to obtain the carrier. Dissolve 15 kg of sodium bicarbonate in water to prepare an impregnating solution, stir and mix it with 50 kg of the carrier, the stirring speed is 220 revolutions per minute, the mixing time is 40 minutes, and let it stand for 1.2 hours. After filtration, dry at 95 °C for 3 hours, heat up to 380 °C at a heating rate of 4 °C / min, and calcine for 2 hours to prepare a liquid-phase low-temperature composite dechlorination agent. After testing, the CaO content in this dechlorination agent is 18%, the NaO content is 20%, the ZnO content is 18%, the alumina content is 30%, and a mixture of 0.8 kg of iron and manganese (mass ratio 1:1, mass percentage content is about 1%) is added. Application test: Load this dechlorination agent in a fixed-bed reactor, use a liquid-phase material containing 500 ppm hydrogen chloride and entraining a small amount of oily substances as the raw material, and carry out the dechlorination test under the conditions of a temperature of 10 °C, a pressure of 0.5 MPa, and an airspeed of 2500 h -1 Under the condition of dechlorination test, after running for 400 hours, the hydrogen chloride content in the outlet material is lower than 7 ppm, there is no caking phenomenon in the dechlorination agent bed, and the breakthrough chlorine capacity reaches 23.8%.

[0028] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various changes or substitutions, and these should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claimed rights.

Claims

1. A preparation method of a liquid-phase low-temperature composite dechlorination agent, characterized in that: Components with the following mass percentages: 8% - 32% CaO, 5% - 25% NaO, 12% - 18% ZnO, 8% - 55% alumina, 0.1% - 2% iron, and 0.1% - 2% manganese.

2. The preparation method of a liquid-phase low-temperature composite dechlorination agent according to claim 1, characterized in that: Including the following steps: S1. Prepare the carrier; S2. Shape, dry, and calcine; S3. Load the second main active component; S4. Perform post-treatment.

3. The preparation method of a liquid-phase low-temperature composite dechlorination agent according to claim 1, characterized in that: In the said S1, the first main active component (calcium hydroxide or / and calcium carbonate), the co-active component (zinc oxide or / and zinc carbonate), the auxiliary materials (powder carrier and pore-forming agent), and the binder (one or two of attapulgite, bentonite, and carboxymethyl cellulose) are mixed evenly in a certain proportion. Among them, the mass ratio of the first main active component accounts for 15% - 35% of the total raw material mass, the co-active component accounts for 8% - 22%, the powder carrier (alumina powder or / and molecular sieve powder) accounts for 25% - 55%, the pore-forming agent (ammonium bicarbonate or / and powdered activated carbon powder) accounts for 6% - 18%, and the binder accounts for 6% - 12%. Use a mixer to stir thoroughly to make them evenly mixed.

4. The preparation method of a liquid-phase low-temperature composite dechlorination agent according to claim 1, characterized in that: In the said S2, the mixed materials are made into a specific shape through an extrusion or rolling ball shaping process. After shaping, dry at a temperature of 110°C - 120°C for 2 - 3 hours to remove moisture. Then, increase the temperature at a heating rate of 3°C / min - 8°C / min to 440°C - 460°C and calcine for 2 - 3 hours to cause physical and chemical changes in the materials, forming a carrier with a certain strength and pore structure.

5. The preparation method of a liquid-phase low-temperature composite dechlorination agent according to claim 1, characterized in that: In the said S3, dissolve the second main active component (one or two of sodium hydroxide, sodium carbonate, and sodium bicarbonate) in an appropriate amount of water to prepare an impregnation solution. The mass of the second main active component is 8% - 22% of the carrier mass. Stir and mix the prepared carrier with the impregnation solution, control the stirring speed at 150 - 250 revolutions per minute, and the mixing time is 40 - 50 minutes. Then, let it stand for 1.2 - 1.8 hours to allow the second main active component to be fully loaded into the pores of the carrier.

6. The preparation method of a liquid-phase low-temperature composite dechlorination agent according to claim 1, characterized in that: In the said S4, after standing, filter to remove the excess impregnation solution. Dry the carrier loaded with the second main active component at a temperature of 95°C - 115°C for 2 - 3 hours to further remove moisture. Finally, increase the temperature at a heating rate of 3°C / min - 8°C / min to 330°C - 390°C and calcine for 2 - 3 hours to make the second main active component better combined with the carrier, obtaining a liquid-phase low-temperature composite dechlorination agent.

7. A preparation method and application of a liquid-phase low-temperature composite dechlorination agent, which is compatible with the preparation method of a liquid-phase low-temperature composite dechlorination agent according to any one of claims 1 to 6, characterized in that: The liquid-phase low-temperature composite dechlorination agent is applicable to the removal of chlorides from various liquid-phase materials, such as the liquid-phase products after reforming reaction, raw materials or intermediate products in fine chemical production, etc., under the pressure conditions of 0-60 °C and 0-3 MPa. In actual applications, the dechlorination agent is filled in a fixed-bed reactor or other suitable reaction devices, and the liquid-phase material passes through the dechlorination agent bed layer at a space velocity of less than 3000 h -1 , achieving efficient removal of chlorides.

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