Gas-phase dechlorination agent, and preparation method and application thereof

Abstract

The present application relates to the field of adsorbent, in particular to a kind of gas phase dechlorination agent and its preparation method and application.The present application provides a kind of preparation method of gas phase dechlorination agent, comprising the following steps: γ-alumina is mixed with alkali metal compound, aging, solid-liquid separation, drying, calcination to obtain first component;Clay and hydrophobic modifier are mixed, solid-liquid separation, drying to obtain second component;First component, second component and basic hydrate are mixed evenly, drying to obtain gas phase dechlorination agent.The present application uses γ-alumina as carrier, through the modification of alkali metal compound, form the γ type metahydroxyapatite with abundant pore and large specific surface area, at the same time, using modifier to modify clay, improve the adsorption and water resistance of gas phase dechlorination agent, further using the ionization performance of basic hydrate, improve the adsorption amount of gas phase dechlorination agent to chloride.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of adsorbents, in particular to a gas-phase dechlorination agent and a preparation method and application thereof. BACKGROUND

[0002] The reaction process of the reforming process will continuously consume and lose the chlorine in the catalyst. In order to ensure the acidity and activity of the reforming catalyst and achieve the best water-chlorine balance, it is necessary to continuously inject the hydrated chloride during the reforming reaction stage and the catalyst regeneration. The excess chloride will generate HCl and chlorine gas at high temperature, which not only seriously corrodes the equipment and pipelines and further affects the subsequent production, but also causes the poisoning of the catalyst and leads to the deactivation of the catalyst. In recent years, the environmental pressure has increased and higher requirements have been put forward for the direct discharge of gas. For the removal of gas-phase chlorides, the gas-phase dechlorination agent adsorption process is mainly used to adsorb the chlorides generated in the reaction. At present, the gas-phase dechlorination agent mostly uses molecular sieves as the skeleton to adsorb chlorides. The dynamic adsorption capacity of this adsorbent is high, but the service life is short.

[0003] The prior art discloses a novel gas-phase dechlorination agent and a preparation method thereof, discloses a gas-phase dechlorination agent with calcium-based or magnesium-based compounds as active components, which can improve the service life of the gas-phase dechlorination agent. However, the adsorption capacity of the gas-phase dechlorination agent for chlorides is not high, and the adsorption capacity of the gas-phase dechlorination agent for chlorides is low in normal temperature and low temperature environments. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the low adsorption capacity of the gas-phase dechlorination agent in the prior art in a low temperature environment, thereby providing a gas-phase dechlorination agent and a preparation method and application thereof, and improving the adsorption capacity of the gas-phase dechlorination agent for chlorides.

[0005] In one aspect, the present application provides a preparation method of a gas-phase dechlorination agent, which comprises the following steps: S1, mixing γ-alumina and an alkali metal compound, aging, solid-liquid separation, drying, and calcining to obtain a first component; S2, mixing clay and a hydrophobic modifier, solid-liquid separation, and drying to obtain a second component; and S3, uniformly mixing the first component, the second component, and an alkali hydrate, and drying to obtain the gas-phase dechlorination agent.

[0006] In one embodiment, the alkali hydrate is an alkali metal compound containing crystal water.

[0007] Preferably, the molar ratio of the alkali metal compound to the crystal water molecule in the alkali hydrate is 1:(1-3).

[0008] In one embodiment, the γ-alumina in step S1 is modified alumina obtained by modifying an alcohol-based additive.

[0009] The preparation method of the modified alumina comprises stirring γ-alumina and alcohol additives at 40-50°C for 20-30min. Optionally, the mass ratio of γ-alumina and alcohol additives is (10-70):(0.1-10).

[0010] Preferably, the alcohol additives are at least one of methanol, ethanol, benzyl alcohol and ethylene glycol.

[0011] Preferably, the γ-alumina has a specific surface area of 100m 2 / g-400m 2 / g and a pore size of 8nm-16nm.

[0012] Preferably, the alkali metal compound is at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate and potassium carbonate.

[0013] Preferably, the basic hydrate is at least one of sodium carbonate monohydrate, potassium carbonate monohydrate and sodium hydroxide monohydrate.

[0014] Preferably, the clay is at least one of dolomite, sepiolite, fly ash, sheep liver soil, montmorillonite and diatomite.

[0015] In one embodiment, the hydrophobic modifier is a quaternary ammonium salt. Preferably, the hydrophobic modifier is at least one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride and tetrabutylammonium bromide.

[0016] In one embodiment, the mass ratio of γ-alumina to alkali metal compound in step S1 is (10-70):(1-40).

[0017] In one embodiment, the mass ratio of clay to hydrophobic modifier in step S2 is (10-30):(0.1-10).

[0018] In one embodiment, the mass ratio of the first component, the second component and the basic hydrate in step S3 is (5-8):(1-3):(1-2).

[0019] In one embodiment, the mass fraction of sodium metaaluminate in the first component obtained in step S1 is 65-90%,

[0020] Optionally, the particle size of the first component is 200-300 mesh.

[0021] In one embodiment, the step of mixing γ-alumina and alkali metal uniformly in step S1 comprises stirring γ-alumina and alkali metal at 150-300°C for 90-120min,

[0022] Optionally, the aging time is 1-4h,

[0023] Optionally, the drying temperature is 100-130℃, and the drying time is 2-5h.

[0024] Optionally, the calcination temperature is 400-500℃, and the calcination time is 3-6h.

[0025] In one embodiment, the step of mixing clay and modifier in step S2 comprises stirring the clay and modifier at 40-80℃ for 60-90min.

[0026] Optionally, the drying temperature is 80-100℃, and the drying time is 4-6h.

[0027] The solid-liquid separation in step S1 and / or step S2 is filtration.

[0028] The drying temperature in step S3 is 60-100℃, preferably, the drying temperature is 60-90℃, and the drying time is 4-6h.

[0029] The preparation method of the basic hydrate comprises wetting the alkali metal with water for 20-40min, and then drying at 60-90℃ for 4-6h.

[0030] In another aspect, the present application provides a gas phase dechlorination agent prepared by the above preparation method. The gas phase dechlorination agent can be applied to adsorb inorganic chlorine in gas phase, and the reaction temperature of the inorganic chlorine in the gas phase is 0-50℃.

[0031] The technical scheme of the present application has the following advantages:

[0032] 1. The present application provides a preparation method of a gas phase dechlorination agent, comprising the following steps: S1, mixing γ-alumina and alkali metal compound, aging, solid-liquid separation, drying, and calcination to obtain a first component; S2, mixing clay and hydrophobic modifier, solid-liquid separation, and drying to obtain a second component; S3, uniformly mixing the first component, the second component, and a basic hydrate, and drying to obtain a gas phase dechlorination agent. The present application uses γ-alumina with specific crystal form and porous properties as a carrier, and through modification of the alkali metal compound, a γ-metallaluminate with rich pores and large specific surface area can be formed. Meanwhile, the present application modifies the clay with a hydrophobic modifier to improve the adsorption and water resistance of the gas phase dechlorination agent. The modified clay, the γ-metallaluminate modified by the alkali metal compound, and the basic hydrate are mixed, and the ionization performance of the basic hydrate is further utilized to improve the adsorption capacity of the gas phase dechlorination agent to chlorides.

[0033] 2. The application provides a preparation method of a gas phase dechlorination agent, wherein the γ-alumina in step S1 is modified γ-alumina obtained by modifying γ-alumina with an alcohol additive. The application uses an alcohol additive containing hydroxyl ions, and the hydroxyl ions in the alcohol additive convert the alumina into metaborate ions, which helps to improve the conversion rate of γ-type metaborate sodium when reacting with a strong base alkali metal compound. Meanwhile, the addition of the alcohol additive helps to form a more regular mesoporous structure and γ-type metaborate with a large specific surface area in the process of modifying γ-alumina with the alkali metal compound, thereby increasing the adsorption capacity of the inner surface. When the gas phase dechlorination agent adsorbs chlorides, the hydrogen chloride molecules can better diffuse inside the carrier, which helps to promote the sufficient reaction between hydrogen chloride and the active component and improve the dechlorination accuracy.

[0034] 3. The application provides a preparation method of a gas phase dechlorination agent, wherein the alkali metal compound is at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate and potassium carbonate. The application uses an alkali metal compound with sodium ions as cations to modify γ-alumina, and uses sodium ions to increase the electron density of the surface oxygen of alumina to make it have super strong alkalinity, so as to obtain γ-type strong alkaline metaborate sodium. The strong alkalinity and rich pore structure of the γ-type metaborate sodium are used to improve the dechlorination reaction rate and internal diffusion rate.

[0035] 4. The application provides a preparation method of a gas phase dechlorination agent, wherein the basic hydrate is at least one of sodium carbonate monohydrate, potassium carbonate monohydrate and sodium hydroxide monohydrate. The application uses a basic hydrate with low water content, and uses the ionization performance of the basic hydrate under the action of trace water on the surface to improve the adsorption capacity of the gas phase dechlorination agent to chlorides, so as to avoid the problems of hardening and water generation when adsorbing chlorides. The application uses the basic hydrate and the γ-type metaborate salt as active components at the same time to improve the adsorption capacity of chlorides.

[0036] 5. The application provides a preparation method of a gas phase dechlorination agent, wherein the hydrophobic modifier is at least one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride and tetrabutylammonium bromide. The application uses a quaternary ammonium salt containing a hydrophilic quaternary ammonium group and a hydrophobic long-chain alkyl group as a hydrophobic modifier to modify clay. The application uses the organic cations of the hydrophobic modifier to exchange with inorganic cations in the clay, so as to change the surface properties of the adsorbent to make it have hydrophobicity, so that the modified clay surface has wetting properties, improves the adsorption performance of the gas phase dechlorination agent, and improves the water resistance of the gas phase dechlorination agent.

[0037] 6.The preparation method of the gas phase dechlorination agent provided by the present application, wherein the mass ratio of the γ-alumina to the alkali metal compound in step S1 is (10-70) : (1-40). In the present application, an excess of γ-alumina is used, and a part of the γ-alumina is modified to form γ-metallate, and the other part of the unreacted γ-alumina and the γ-metallate interact with each other, which can improve the stability of the carrier structure.

[0038] 7.The preparation method of the gas phase dechlorination agent provided by the present application, wherein the drying temperature in step S3 is 60-100℃, preferably 60-90℃, and the drying time is 4-6h. In the preparation method of the gas phase dechlorination agent provided by the present application, each component is dried under low temperature conditions to obtain the gas phase dechlorination agent, which can maintain the original active component form and pore structure of the gas phase dechlorination agent, and prevent the active component from agglomerating and deactivating due to high temperature calcination.

[0039] 8.The gas phase dechlorination agent provided by the present application or the gas phase dechlorination agent prepared by the preparation method of the gas phase dechlorination agent, which can adsorb chlorides under normal temperature or low temperature conditions. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0041] Figure 1 is the process flow chart of the preparation method of the gas phase dechlorination agent in Example 1 of the present application. DETAILED DESCRIPTION

[0042] The following examples are provided to better further understand the present application, and are not limited to the best embodiments, and do not limit the content and protection scope of the present application. Any product obtained by the inspiration of the present application or the combination of the present application with other prior art features, which is the same as or similar to the present application, falls within the protection scope of the present application.

[0043] In the examples, the specific experimental steps or conditions are not specified, and can be performed according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments used are not specified by the manufacturer, and are conventional reagent products that can be obtained by purchase.

[0044] Example 1

[0045] Reference Figure 1 As shown in the present embodiment, a preparation method of a gas phase dechlorination agent is provided, and the specific steps and parameters are as follows:

[0046] (1) adding 200 mL of 2% methanol solution to 50 g of γ-alumina, stirring at 40°C for 20 min to obtain a first mixture, wherein the specific surface area of the γ-alumina is 400 m 2 / g, and the pore size is 10 nm;

[0047] (2) adding 27.4 g of sodium hydroxide to the first mixture, stirring at 200°C for 90 min, and aging for 1 h to obtain a second mixture;

[0048] filtering the second mixture, drying at 120°C for 2 h, and calcining at 400°C for 4 h to obtain a first component, wherein the mass fraction of sodium metaaluminate in the first component is 80%, and the first component is crushed to a particle size range of 200-300 mesh.

[0049] (3) adding 50 mL of 0.5% cetyltrimethylammonium bromide solution to 20 g of montmorillonite, stirring at 40°C for 60 min, filtering, and drying at 100°C for 4 h to obtain a second component;

[0050] (4) adding 15 g of sodium carbonate, wetting with water for 30 min, and drying at 60°C for 4 h to obtain sodium carbonate monohydrate;

[0051] (5) mixing the first component, the second component, and the sodium carbonate monohydrate in a mass ratio of 12:4:3, rolling into balls, and drying at 90°C for 6 h to obtain the gas phase dechlorination agent.

[0052] Example 2

[0053] The embodiment provides a preparation method of a gas phase dechlorination agent, and specific steps and parameters are as follows:

[0054] (1) adding 200 mL of 2% ethanol solution to 50 g of γ-alumina, stirring at 40°C for 20 min to obtain a first mixture, wherein the specific surface area of the γ-alumina is 400 m 2 / g, and the pore size is 10 nm;

[0055] (2) adding 36.32 g of sodium carbonate to the first mixture, stirring at 200°C for 90 min, and aging for 1 h to obtain a second mixture;

[0056] filtering the second mixture, drying at 120°C for 2 h, and calcining at 500°C for 4 h to obtain a first component, wherein the mass fraction of sodium metaaluminate in the first component is 82%, and the first component is crushed to a particle size range of 200-300 mesh.

[0057] (3), 10g sepiolite is added with 50ml of 1.5% hexadecyl trimethyl ammonium bromide solution, mixed, stirred at 40°C for 60min, filtered, dried at 100°C for 4h to obtain the second component;

[0058] (4), 15g of sodium carbonate is weighed and wetted with water for 20min, dried at 75°C for 5h to obtain sodium carbonate monohydrate;

[0059] (5), the first component, the second component and sodium carbonate monohydrate are mixed uniformly according to the mass ratio of 12:4:3, and are formed into balls, dried at 90°C for 6h to obtain the gas phase dechlorination agent.

[0060] Example 3

[0061] The embodiment provides a preparation method of a gas phase dechlorination agent, and specific steps and parameters are as follows:

[0062] (1), 60g of γ-alumina is added with 200ml of 2% ethylene glycol solution, stirred at 40°C for 20min to obtain a first mixed solution, wherein the specific surface area of the γ-alumina is 400m 2 / g, and the pore size is 10nm;

[0063] (2), 27.4g of sodium bicarbonate is weighed and added into the first mixed solution, stirred at 200°C for 90min, and aged for 1h to obtain a second mixed solution;

[0064] The second mixed solution is filtered, dried at 120°C for 2h, and then calcined at 400°C for 4h to obtain a first component, wherein the mass fraction of sodium metaaluminate in the first component is 70%, and the first component is crushed to a particle size of 200-300 mesh.

[0065] (3), 10g sepiolite is added with 50ml of 1.5% hexadecyl trimethyl ammonium bromide solution, mixed, stirred at 40°C for 60min, filtered, dried at 100°C for 4h to obtain the second component;

[0066] (4), 15g of sodium carbonate is weighed and wetted with water for 20min, dried at 75°C for 5h to obtain sodium carbonate monohydrate;

[0067] (5), the first component, the second component and sodium carbonate monohydrate are mixed uniformly according to the mass ratio of 12:4:3, and are formed into balls, dried at 90°C for 6h to obtain the gas phase dechlorination agent.

[0068] Example 4

[0069] The embodiment provides a preparation method of a gas phase dechlorination agent, and specific steps and parameters are as follows:

[0070] (1), to 10 g of γ-alumina, add 5 mL of benzyl alcohol solution with a concentration of 2%, stir at 50°C for 30 min, to obtain a first mixed solution, wherein the specific surface area of γ-alumina is 200 m 2 / g, and the pore size is 8 nm;

[0071] (2), take 1 g of sodium hydroxide and add it to the first mixed solution, stir at 150°C for 120 min, and age for 2 h, to obtain a second mixed solution;

[0072] Filter the second mixed solution, dry at 100°C for 4 h, and then calcine at 500°C for 3 h, to obtain a first component, the mass fraction of sodium metaaluminate in the first component being 65%, and the first component is crushed to a particle size of 200-300 mesh.

[0073] (3), to 10 g of fly ash, add 50 mL of hexadecyl trimethyl ammonium bromide solution with a concentration of 0.5%, mix, stir at 80°C for 80 min, filter, and dry at 80°C for 6 h, to obtain a second component;

[0074] (4), take 5 g of sodium hydroxide, wet with water for 40 min, and dry at 90°C for 6 h, to obtain sodium hydroxide monohydrate;

[0075] (5), mix the first component, the second component, and the sodium hydroxide monohydrate in a mass ratio of 5:3:1, roll into balls, and dry at 60°C for 5 h, to obtain the gas phase dechlorination agent.

[0076] Example 5

[0077] The embodiment provides a preparation method of a gas phase dechlorination agent, and specific steps and parameters are as follows:

[0078] (1), to 70 g of γ-alumina, add 200 mL of ethanol solution with a concentration of 6%, stir at 40°C for 20 min, to obtain a first mixed solution, wherein the specific surface area of γ-alumina is 100 m 2 / g, and the pore size is 16 nm;

[0079] (2), take 40 g of sodium bicarbonate and add it to the first mixed solution, stir at 300°C for 90 min, and age for 4 h, to obtain a second mixed solution;

[0080] Filter the second mixed solution, dry at 130°C for 5 h, and then calcine at 400°C for 6 h, to obtain a first component, the mass fraction of sodium metaaluminate in the first component being 90%, and the first component is crushed to a particle size of 200-300 mesh.

[0081] (3), to 30 g of diatomite, add 95 mL of tetrabutyl ammonium bromide solution with a concentration of 10%, mix, stir at 40°C for 90 min, filter, and dry at 100°C for 4 h, to obtain a second component;

[0082] (4) Weigh 25 g of sodium carbonate, wet with water for 30 min, and dry at 60°C for 4 h to obtain sodium carbonate monohydrate;

[0083] (5) Mix the first component, the second component, and sodium carbonate monohydrate in a mass ratio of 8:1:2, roll into balls, and dry at 90°C for 6 h to obtain the gas-phase dechlorination agent.

[0084] Example 6

[0085] This example provides a preparation method of a gas-phase dechlorination agent. The specific steps and parameters are the same as those in Example 1, except that an equal amount of ethanol is used to replace the cetyltrimethylammonium bromide solution in step (3). Specifically, 20 g of montmorillonite is mixed with 50 mL of an ethanol solution with a concentration of 0.8%, stirred at 40°C for 60 min, filtered, and dried at 100°C for 4 h to obtain the second component.

[0086] Example 7

[0087] This example provides a preparation method of a gas-phase dechlorination agent. The specific steps and parameters are the same as those in Example 1, except that the drying temperature in step (5) is 100°C.

[0088] Example 8

[0089] This example provides a preparation method of a gas-phase dechlorination agent. The specific steps and parameters are the same as those in Example 1, except that an equal amount of potassium carbonate is used to replace sodium hydroxide in step (2). Specifically, 27.4 g of potassium carbonate is weighed and added to the first mixed solution, stirred at 200°C for 90 min, and aged for 1 h to obtain the second mixed solution.

[0090] Example 9

[0091] This example provides a preparation method of a gas-phase dechlorination agent. The specific steps and parameters are the same as those in Example 1, except that step (4) is omitted, and an equal amount of sodium acetate trihydrate is used to replace sodium carbonate monohydrate in step (5).

[0092] Comparative Example 1

[0093] This comparative example provides a preparation method of a gas-phase dechlorination agent. The specific steps and parameters are the same as those in Example 1, except that an equal amount of α-alumina is used to replace γ-alumina in step (1) of Example 1.

[0094] Comparative Example 2

[0095] This comparative example provides a preparation method of a gas-phase dechlorination agent. The specific steps and parameters are as follows:

[0096] (1), 50g of γ-alumina was added with 200ml of methanol solution with a concentration of 2%, stirred at 40°C for 20min, to obtain a first mixture, wherein the specific surface area of γ-alumina was 400m 2 / g, and the pore size was 10nm;

[0097] (2), 27.4g of sodium hydroxide was weighed and added to the first mixture, stirred at 200°C for 90min, and aged for 1h to obtain a second mixture;

[0098] The second mixture was filtered, dried at 120°C for 2h, and then calcined at 400°C for 4h to obtain a first component, the mass fraction of sodium metaaluminate in the first component was 80%, and the first component was crushed to a particle size of 200-300 mesh.

[0099] (3), 20g of montmorillonite was weighed as a second component;

[0100] (4), 15g of sodium carbonate was weighed, wetted with water for 30min, and dried at 60°C for 4h to obtain sodium carbonate monohydrate;

[0101] (5), the first component, the second component and sodium carbonate monohydrate were mixed uniformly according to a mass ratio of 12:4:3, and were formed into balls, dried at 90°C for 6h to obtain the gas phase dechlorination agent.

[0102] Comparative Example 3

[0103] This comparative example provides a preparation method of a gas phase dechlorination agent, and the specific steps and parameters are as follows:

[0104] (1), 50g of γ-alumina was added with 200ml of methanol solution with a concentration of 2%, stirred at 40°C for 20min, to obtain a first mixture, wherein the specific surface area of γ-alumina was 400m 2 / g, and the pore size was 10nm;

[0105] (2), 27.4g of sodium hydroxide was weighed and added to the first mixture, stirred at 200°C for 90min, and aged for 1h to obtain a second mixture;

[0106] The second mixture was filtered, dried at 120°C for 2h, and then calcined at 400°C for 4h to obtain a first component, the mass fraction of sodium metaaluminate in the first component was 80%, and the first component was crushed to a particle size of 200-300 mesh.

[0107] (3), 20g of montmorillonite was added with 50ml of cetyltrimethylammonium bromide solution with a concentration of 0.5%, stirred at 40°C for 60min, filtered, and dried at 100°C for 4h to obtain a second component;

[0108] (4) The first component, the second component and sodium carbonate are mixed in a mass ratio of 12:4:3, and are ball-shaped, and are dried at 90°C for 6h to obtain the gas-phase dechlorination agent.

[0109] Comparative Example 4

[0110] The present comparative example provides a preparation method of a gas-phase dechlorination agent, and the specific steps and parameters are as follows:

[0111] 50g of γ-alumina, 27.4g of sodium hydroxide, 20g of montmorillonite, 50mL of a 0.5% cetyltrimethylammonium bromide solution, and 15g of sodium carbonate monohydrate are mixed uniformly, ball-shaped, and dried at 90°C for 6h to obtain the gas-phase dechlorination agent.

[0112] Comparative Example 5

[0113] The present comparative example provides a preparation method of a gas-phase dechlorination agent, and the specific steps and parameters are as follows:

[0114] (1) 60g of sodium metaaluminate is calcined at 400°C for 4h to obtain a first component, the mass fraction of sodium metaaluminate in the first component is 80%, and the first component is crushed to a particle size range of 200-300 mesh, and the sodium metaaluminate is purchased from the National Pharmaceutical Group.

[0115] (3) 20g of montmorillonite is added with 50mL of a 0.5% cetyltrimethylammonium bromide solution, stirred at 40°C for 60min, filtered, and dried at 100°C for 4h to obtain a second component;

[0116] (4) 15g of sodium carbonate is weighed, wetted with water for 30min, and dried at 60°C for 4h to obtain sodium carbonate monohydrate;

[0117] (5) The first component, the second component and sodium carbonate monohydrate are mixed in a mass ratio of 12:4:3, and are ball-shaped, and are dried at 90°C for 6h to obtain the gas-phase dechlorination agent.

[0118] Application Example 1

[0119] The gas-phase dechlorination agents prepared in Examples 1-9 and Comparative Examples 1-5 are loaded into a reactor, and chlorides are adsorbed under the conditions of 10°C and normal pressure, the inner diameter of the reactor is 10mm, the loading amount of the gas-phase dechlorination agent is 3.2ml, and the particle size of the gas-phase dechlorination agent is 40-60 mesh.

[0120] Application Example 2

[0121] The gas-phase dechlorination agent prepared in Example 1 is loaded into a reactor, and chlorides are adsorbed under the conditions of 0°C and normal pressure, the inner diameter of the reactor is 10mm, the loading amount of the gas-phase dechlorination agent is 3.2ml, and the particle size of the gas-phase dechlorination agent is 40-60 mesh.

[0122] Example 3

[0123] The gas phase dechlorination agent prepared in Example 1 was packed in a reactor, and the adsorption of chlorides was carried out at 30°C under normal pressure. The inner diameter of the reactor was 10 mm, the packing amount of the gas phase dechlorination agent was 3.2 ml, and the particle size of the gas phase dechlorination agent was 40-60 mesh.

[0124] Example 4

[0125] The gas phase dechlorination agent prepared in Example 1 was packed in a reactor, and the adsorption of chlorides was carried out at 50°C under normal pressure. The inner diameter of the reactor was 10 mm, the packing amount of the gas phase dechlorination agent was 3.2 ml, and the particle size of the gas phase dechlorination agent was 40-60 mesh.

[0126] Example 1

[0127] The adsorption performance of the gas phase dechlorination agent of Examples 1-4 on chlorides was detected, and the detection results are shown in Table 1.

[0128] The detection method is as follows:

[0129] The inlet hydrogen chloride and the outlet hydrogen chloride concentration were tested by using a GT-2000-HCL-CL hydrogen chloride gas analyzer. The hydrogen chloride concentration before the reaction was 6000 ppm, and the outlet chlorine content > 0.2 ppm was regarded as breakthrough.

[0130] The chlorine content in the gas phase dechlorination agent after the reaction was measured by using a Swiss Wanthong 905 (905 Titrando) type automatic potentiometric titrator, and was recorded as A.

[0131] The chlorine content of the gas phase dechlorination agent was represented by X, and was calculated according to the following formula:

[0132] X = m2 / m1 x A

[0133] In the formula, m1 is the mass of the gas phase dechlorination agent before the reaction, g;

[0134] m2 is the mass of the gas phase dechlorination agent after the reaction, g.

[0135] Table 1: Performance detection results of the gas phase dechlorination agent

[0136]

[0137]

[0138] According to Table 1, compared with Comparative Examples 1-5, the present application uses alkali metal modified alumina to prepare sodium metaaluminate, and uses alkaline hydrate as active component, and through the joint action of modified clay, effectively improves the adsorption capacity of gas phase dechlorination agent and chloride, and can reduce the outlet hydrogen chloride content to 0.01 ppm, and the breakthrough chlorine capacity can reach 33.98%. In a low temperature environment, i.e. 0-10℃, the gas phase dechlorination agent prepared by the present application can still reduce the outlet hydrogen chloride content to 0.02 ppm, and the breakthrough chlorine capacity can reach 29.69%. The temperature for drying the gas phase dechlorination agent in Example 7 is slightly high, which causes a certain amount of active component to be inactivated, and the chloride adsorption capacity is reduced. In Example 8, potassium carbonate is used to replace sodium hydroxide as an alkali metal compound, and the prepared sodium metaaluminate is not strong in alkalinity, which leads to a slightly poor absorption effect on chloride. In Example 9, sodium acetate trihydrate is used as an alkaline hydrate, and the prepared gas phase dechlorination agent produces a certain amount of water and hardening phenomenon when absorbing chloride, which increases the water resistance of the gas phase dechlorination agent, leading to poor absorption effect on chloride. The effect of α-alumina on absorbing chloride in Comparative Example 1 is poor, which is due to the poor activity of α-alumina, and the active component of the gas phase dechlorination agent cannot effectively absorb chloride. In Comparative Example 2, the gas phase dechlorination agent is not modified by a hydrophobic modifier, and in Comparative Example 3, the alkali metal compound is used to replace the alkaline hydrate, and in Comparative Example 4, only the raw materials are mixed and dried to obtain the gas phase dechlorination agent, and the effect of absorbing chloride is poor. In Comparative Example 5, the commercially available sodium metaaluminate is actually a coordination compound, not sodium metaaluminate. The technical scheme of the present application can prepare γ-type metaaluminate with specific crystal form and porosity by using γ-alumina and alkali metal compound as raw materials, thereby improving the dechlorination effect of the gas phase dechlorination agent. At the same time, the gas phase dechlorination agent prepared by the present application can absorb chloride at room temperature, and the chloride adsorption capacity at low temperature can also meet the actual application.

[0139] Experimental Example 2

[0140] The hydrophobic properties of the gas phase dechlorination agents prepared in Examples 1-9 and Comparative Examples 1-4 were detected, and the detection results are shown in Table 2.

[0141] The hydrophobic property detection method: the gas phase dechlorination agents prepared in Examples 1-9 and Comparative Examples 1-4 were used to absorb chloride by using the steps and parameters of Application Example 1, and the difference was that the chloride was chloride containing 2400 ppm water vapor, and other conditions were unchanged. Whether the dechlorination agent had hardening and mudification phenomenon after the reaction was used to evaluate the hydrophobicity of the dechlorination agent. Among them, when the amount of dechlorination agent with hardening and mudification phenomenon was less than 1 / 3 of the loading amount of the gas phase dechlorination agent, the hydrophobic property was evaluated as good; when the amount of dechlorination agent with hardening and mudification phenomenon was greater than or equal to 1 / 3 and less than or equal to 2 / 3 of the loading amount of the gas phase dechlorination agent, the hydrophobic property was evaluated as general; and when the amount of dechlorination agent with hardening and mudification phenomenon was greater than 2 / 3 of the loading amount of the gas phase dechlorination agent, the hydrophobic property was evaluated as poor.

[0142] Table 2 Hydrophobic property of gas phase dechlorination agent

[0143] Examples / Comparative Examples Hydrophobic properties Examples / Comparative Examples Hydrophobic properties Example 1 Good Example 8 Good Example 2 Good Example 9 General Example 3 Good Comparative Example 1 Good general Example 4 Good Comparative Example 2 Poor Example 5 Good Comparative Example 3 General Example 6 General Comparative Example 4 Poor Example 7 Good Comparative Example 5 General

[0144] According to the data in Table 2, the gas phase dechlorination agent prepared by using the hydrophobic modifier to modify the clay has good hydrophobic property. Meanwhile, when the molar ratio of the alkali metal compound and the crystal water is 1:3, the gas phase dechlorination agent prepared has a problem of hardening easily when adsorbing chlorides, thereby affecting the dechlorination effect.

[0145] Obviously, the above examples are only examples for clearly illustrating but not limitation to the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be enumerated and it is impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A process for the preparation of a gas phase dechlorination agent, characterized in that, The method comprises the following steps: S1, mixing modified γ-alumina and alkali metal compound, aging, solid-liquid separation, drying, and calcination to obtain a first component; the preparation method of the modified alumina comprises stirring γ-alumina and alcohol additive at 40-50℃ for 20-30min; the mass ratio of γ-alumina to alcohol additive is (10-70):(0.1-10); S2, mixing clay and hydrophobic modifier, solid-liquid separation, and drying to obtain a second component; S3, uniformly mixing the first component, the second component, and alkaline hydrate, and drying to obtain a gas phase dechlorination agent; The alkali metal compound is at least one of sodium carbonate, sodium hydroxide, sodium bicarbonate, and potassium carbonate; The alkaline hydrate is at least one of sodium carbonate monohydrate, potassium carbonate monohydrate, and sodium hydroxide monohydrate; The hydrophobic modifier is at least one of cetyltrimethylammonium bromide, cetyltrimethylammonium chloride, and tetrabutylammonium bromide.

2. The method for producing a gas-phase dechlorination agent according to claim 1, characterized by, The γ-alumina has a specific surface area of 100 m 2 / g~400 m 2 / g, and a pore size of 8 nm~16 nm.

3. The method for producing a gas-phase dechlorination agent according to claim 2, characterized by, The clay is at least one of dolomite, sepiolite, fly ash, sheep liver soil, montmorillonite, and diatomite; and / or, The alcohol additive is at least one of methanol, ethanol, benzyl alcohol, and ethylene glycol.

4. The process for the preparation of a gas-phase dechlorination agent according to any one of claims 1 to 3, characterized in that, In step S1, the mass ratio of γ-alumina to alkali metal compound is (10-70):(1-40); and / or, In step S2, the mass ratio of clay to hydrophobic modifier is (10-30):(0.1-10); and / or, In step S3, the mass ratio of the first component to the second component to alkaline hydrate is (5-8):(1-3):(1-2).

5. The method for producing a gas-phase dechlorination agent according to claim 4, characterized by, In the first component obtained in step S1, the mass fraction of sodium metaaluminate is 65-90%; and / or, The particle size of the first component is 200-300 mesh; and / or, The mixing step in step S1 comprises stirring at 150-300℃ for 90-120min; and / or, The aging time is 1-4h; and / or, In step S1, the drying temperature is 100-130℃, and the drying time is 2-5h; and / or, In step S1, the calcination temperature is 400-500℃, and the calcination time is 3-6h.

6. The method for producing a gas-phase dechlorination agent according to claim 5, characterized by, In step S2, the mixing step of clay and modifier comprises stirring clay and modifier at 40-80℃ for 60-90min; and / or, In step S2, the drying temperature is 80-100℃, and the drying time is 4-6h; and / or, The solid-liquid separation step in step S1 and / or step S2 is filtration.

7. The method for producing a gas-phase dechlorination agent according to claim 6, characterized by, The drying temperature in step S3 is 60-100℃.

8. The method for producing a gas-phase dechlorination agent according to claim 7, characterized by, The drying temperature is 60-90℃, and the drying time is 4-6h; and / or, The preparation method of the alkaline hydrate comprises wetting the alkali metal with water for 20-40min, and then drying at 60-90℃ for 4-6h.

9. A gas phase dechlorination agent, characterized by, The preparation method of the gas phase dechlorination agent is the preparation method of the gas phase dechlorination agent according to any one of claims 1-8.

10. Use of a gas-phase dechlorination agent according to claim 9 for adsorbing inorganic chlorine in a gas phase, characterized in that, The reaction temperature for adsorbing inorganic chlorine in gas phase is 0-50℃.

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