A liquid phase dechlorination agent and its preparation method and application

Abstract

The present invention belongs to the field of dechlorination technology, and specifically relates to a liquid-phase dechlorinating agent, a preparation method thereof, and an application thereof. The liquid-phase dechlorinating agent provided by the present invention comprises the following raw material components in parts by weight: 10-70 parts of a mesoporous molecular sieve; 1-20 parts of an alkali metal compound; 10-30 parts of an active ingredient; 0.1-5 parts of a quaternary ammonium salt compound; and 10-30 parts of a binder. The mesoporous molecular sieve has a silicon-aluminum molar ratio of (10-100):1 and a specific surface area of ​​500-1000 m 2 / g, with a pore size of 2-10nm. The dechlorination agent formed by the interaction of a specific high silicon-aluminum ratio mesoporous molecular sieve, an alkali metal compound, an active component, a quaternary ammonium salt compound, and a binder can simultaneously and efficiently remove organic chlorine and inorganic chlorine.

Description

Technical Field

[0001] The invention belongs to the technical field of dechlorination, and particularly relates to a liquid phase dechlorination agent and a preparation method and application thereof. Background Art

[0002] During the catalytic reforming reaction, chlorine in the reformed oil can have a series of adverse effects on subsequent equipment. my country began researching dechlorination agents in the 1970s, and while gas-phase dechlorination technology is now relatively mature, progress in liquid-phase dechlorination technology has been slow, particularly in the removal of organic chlorine.

[0003] In the prior art, Chinese patent document CN104437342A discloses a high-chlorine-capacity liquid-phase dechlorinating agent and its preparation method. The liquid-phase dechlorinating agent carrier is a carbon molecular sieve, the active component is an alkali metal and alkaline earth metal oxide, and the auxiliary component is iron oxide, copper oxide, or zinc oxide. CN104560126A discloses a dechlorinating agent for removing chloride ions from reformed gasoline. The dechlorinating agent is composed of a microporous alumina composite carrier and multiple dechlorination active substances containing Group IA, IIA, and IIB elements. The composite carrier is composed of multiple carriers with pore sizes greater than 50 nm, pore sizes between 2 and 50 nm, and pore sizes less than 2 nm. This dechlorinating agent can improve the removal efficiency of inorganic Cl ions in reformed gasoline. However, existing dechlorinating agents are poorly effective in removing both organic and inorganic chlorine under liquid phase conditions. Therefore, there is an urgent need to develop a dechlorinating agent with excellent performance in removing both organic and inorganic chlorine under liquid phase conditions. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect of the existing dechlorination agent in removing organic chlorine and inorganic chlorine simultaneously under liquid phase conditions, thereby providing a liquid phase dechlorination agent and its preparation method and application.

[0005] The present invention provides a liquid-phase dechlorination agent comprising the following raw material components in parts by weight:

[0006] 10-70 parts of mesoporous molecular sieve;

[0007] 1-20 parts of an alkali metal compound;

[0008] 10-30 parts of active ingredient;

[0009] 0.1-5 parts of quaternary ammonium salt compound;

[0010] 10-30 parts of binder;

[0011] The mesoporous molecular sieve has a silicon to aluminum molar ratio of (10-100):1 and a specific surface area of ​​500-1000m 2 / g, pore size is 2-10nm.

[0012] Preferably, the mesoporous molecular sieve is at least one selected from MCM-41 molecular sieve, SBA-15 molecular sieve, and MCM-48 molecular sieve;

[0013] The quaternary ammonium salt compound is at least one selected from tetramethylammonium hydroxide, tetramethylammonium nitrate, tetramethylammonium bromide, and tetrabutylammonium bromide.

[0014] Preferably, the alkali metal compound is selected from at least one of potassium carbonate, potassium hydroxide, sodium carbonate and sodium hydroxide;

[0015] The active component is selected from at least one of zinc oxide, copper oxide, basic zinc carbonate, and basic copper carbonate;

[0016] The binder is selected from at least one of sesbania powder, attapulgite, kaolin, silica sol, and sodium carboxymethyl cellulose.

[0017] Optionally, the binder is selected from attapulgite, sesbania powder and sodium carboxymethyl cellulose, and the mass ratio of the attapulgite, sesbania powder and sodium carboxymethyl cellulose is 10: (1-2): (1-2);

[0018] Optionally, the binder is selected from kaolin, sesbania powder and sodium carboxymethyl cellulose, and the mass ratio of the kaolin, sesbania powder and sodium carboxymethyl cellulose is 10: (1-2): (1-2);

[0019] The present invention provides a method for preparing the liquid-phase dechlorinating agent described above, comprising the following steps:

[0020] 1) preparing an alkali metal compound into an alkali metal compound aqueous solution, and mixing the solution with a mesoporous molecular sieve to obtain a mixture;

[0021] 2) mixing the mixture in step 1) with an active component and a binder, and forming, drying, and calcining to obtain a dechlorination agent precursor;

[0022] 3) The quaternary ammonium salt compound is prepared into a quaternary ammonium salt compound aqueous solution, and then the dechlorination agent precursor is immersed in the quaternary ammonium salt compound aqueous solution, and dried to obtain the liquid phase dechlorination agent.

[0023] Preferably, the concentration of the aqueous solution of the alkali metal compound in step 1) is 0.1-1 g / mL;

[0024] The mass ratio of the alkali metal compound aqueous solution to the mesoporous molecular sieve is 1:(1-10).

[0025] Preferably, the forming in step 2) is extrusion forming, and the step of adding water is further included before the extrusion forming; the present invention uses water to adjust the dryness and wetness to ensure that the extrusion state is achieved;

[0026] The drying temperature is 100-120°C and the drying time is 2-5h;

[0027] The calcination temperature is 200-500° C., and the calcination time is 2-4 hours.

[0028] Preferably, the concentration of the aqueous solution of the quaternary ammonium salt compound in step 3) is 0.001-0.1 g / mL;

[0029] Optionally, the mass ratio of the quaternary ammonium salt compound aqueous solution to the dechlorination agent precursor may be 1:(1-10).

[0030] Preferably, the immersion temperature in step 3) is 30-60° C., and the immersion time is 1-5 h;

[0031] The drying temperature is 80-120° C., and the drying time is 2-6 hours.

[0032] The present invention provides an application of the above-mentioned liquid-phase dechlorination agent or the liquid-phase dechlorination agent prepared by the above-mentioned method in liquid-phase dechlorination of reforming oil.

[0033] The present invention also provides a use of the liquid-phase dechlorinating agent described above or the liquid-phase dechlorinating agent prepared by the method described above in removing inorganic chlorine and organic chlorine.

[0034] The technical solution of the present invention has the following advantages:

[0035] (1) The liquid phase dechlorination agent provided by the present invention comprises the following raw material components in parts by weight: 10-70 parts of a mesoporous molecular sieve; 1-20 parts of an alkali metal compound; 10-30 parts of an active ingredient; 0.1-5 parts of a quaternary ammonium salt compound; and 10-30 parts of a binder. The mesoporous molecular sieve has a silicon to aluminum molar ratio of (10-100):1 and a specific surface area of ​​500-1000 m 2 / g, pore size of 2-10nm. The liquid-phase dechlorination agent provided by the present invention uses a mesoporous molecular sieve with a high silicon-aluminum ratio as a carrier. The specific molecular sieve shows a high affinity for organic groups and contains active groups on the surface, which can be combined with quaternary ammonium salt compounds in a covalent bond manner, so that they are better loaded on the surface; the introduction of the quaternary ammonium salt compound organic group as a phase transfer catalyst promotes the conversion of organic chlorine into inorganic chlorine, and the generated chloride ions react with the active components to achieve the purpose of removing inorganic chlorine and organic chlorine simultaneously. The mesoporous molecular sieve with a high silicon-aluminum ratio as a carrier has hydrophobicity and can also improve the water resistance of the dechlorination agent and reduce the compaction of the dechlorination agent; the mesoporous structure provides larger pores and pore volume, increasing the adsorption capacity of the inner surface, so that the alkali metal compound can be evenly distributed inside the pores; the large specific surface area is conducive to the distribution of active sites and increases the contact between the active sites and the reactants. The added binder has a pore-forming effect after roasting, increasing the overall specific surface area and pore volume, which can better promote the conversion and removal of chlorides. The alkali metal compound is added as a solution, allowing for more uniform dispersion within the carrier. Simultaneously adding a transition metal as an active component improves dechlorination accuracy. The dechlorinator, formed by the interaction of a specific high-silicon-to-aluminum ratio mesoporous molecular sieve, an alkali metal compound, an active component, a quaternary ammonium salt compound, and a binder, can simultaneously and efficiently remove both organic and inorganic chlorine.

[0036] (2) The liquid-phase dechlorination agent provided by the present invention comprises the following: the mesoporous molecular sieve is selected from at least one of MCM-41 molecular sieve, SBA-15 molecular sieve, and MCM-48 molecular sieve; the quaternary ammonium salt compound is selected from at least one of tetramethylammonium hydroxide, tetramethylammonium nitrate, tetramethylammonium bromide, and tetrabutylammonium bromide; the alkali metal compound is selected from at least one of potassium carbonate, potassium hydroxide, sodium carbonate, and sodium hydroxide; the active component is selected from at least one of zinc oxide, copper oxide, basic zinc carbonate, and basic copper carbonate; and the binder is selected from at least one of sesbania powder, attapulgite, kaolin, silica sol, and sodium carboxymethyl cellulose. By limiting the types of alkali metal compounds, quaternary ammonium salt compounds, active components, and binders, and combining them with a limited pore molecular sieve carrier, the present invention can further improve the removal rate of the dechlorination agent for organic chlorine and inorganic chlorine, and the dechlorination accuracy can reach below 0.5 mg / L.

[0037] (3) The preparation method of the liquid-phase dechlorinating agent provided by the present invention comprises the following steps: 1) configuring an alkali metal compound into an alkali metal compound aqueous solution, and mixing it with a mesoporous molecular sieve to obtain a mixture; 2) mixing the mixture in step 1) with an active component, a binder, and water, and forming, drying, and roasting to obtain a dechlorinating agent precursor; 3) configuring a quaternary ammonium salt compound into a quaternary ammonium salt compound aqueous solution, and then placing the dechlorinating agent precursor in the quaternary ammonium salt compound aqueous solution for impregnation, and drying to obtain the liquid-phase dechlorinating agent. The present invention configures the alkali metal compound into a solution and first mixes it with the mesoporous molecular sieve, so that it is more evenly dispersed inside the mesoporous molecular sieve. After the quaternary ammonium salt compound is impregnated, the quaternary ammonium salt compound is more evenly combined with the mesoporous molecular sieve and the active substance. It can better promote the conversion of organic chlorides and improve the removal of organic chlorine and inorganic chlorine. DETAILED DESCRIPTION

[0038] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0039] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0040] Example 1

[0041] This embodiment provides a method for preparing a liquid-phase dechlorinating agent, comprising the following steps:

[0042] 1) Prepare a sodium hydroxide aqueous solution with a concentration of 0.3 g / mL, and mix 35 g of the 0.3 g / mL sodium hydroxide aqueous solution with 50 g of SBA-15 molecular sieve carrier (silicon-aluminum molar ratio of 20:1, specific surface area of ​​800 m 2 / g, pore size of 5 nm) to obtain a mixture;

[0043] 2) The mixture in step 1) was mixed with 20 g of zinc oxide, 20 g of attapulgite, 2 g of sesbania powder, and 2 g of sodium carboxymethyl cellulose powder, and an appropriate amount of water was added to reach an extrudable state, extruded into strips, dried at 120° C. for 2 h, and calcined at 480° C. for 2 h to obtain a dechlorination agent precursor;

[0044] 3) preparing a tetramethylammonium hydroxide aqueous solution with a concentration of 0.003 g / mL, and immersing the dechlorinating agent precursor in 50 mL of the 0.003 g / mL tetramethylammonium hydroxide solution at a temperature of 40° C. for 2 h. After drying at 90° C. for 3 h, the liquid dechlorinating agent is obtained.

[0045] Example 2

[0046] This embodiment provides a method for preparing a liquid-phase dechlorinating agent, comprising the following steps:

[0047] 1) Prepare a sodium carbonate aqueous solution with a concentration of 0.2 g / mL, and mix 30 g of the 0.2 g / mL sodium carbonate aqueous solution with 50 g of MCM-41 molecular sieve carrier (silicon-aluminum molar ratio of 25:1, specific surface area of ​​1000 m 2 / g, pore size of 4 nm) to obtain a mixture;

[0048] 2) The mixture in step 1) was mixed with 20 g of zinc oxide, 20 g of attapulgite, 2 g of sesbania powder, and 2 g of sodium carboxymethyl cellulose powder, and an appropriate amount of water was added to reach an extrudable state, extruded into strips, dried at 110° C. for 2 h, and calcined at 500° C. for 2 h to obtain a dechlorination agent precursor;

[0049] 3) preparing a 0.005 g / mL aqueous solution of tetramethylammonium bromide, and immersing the dechlorinating agent precursor in 50 mL of the 0.005 g / mL aqueous solution of tetramethylammonium bromide at a temperature of 30° C. for 2 h. The dechlorinating agent was dried at 100° C. for 3 h to obtain the liquid dechlorinating agent.

[0050] Example 3

[0051] This embodiment provides a method for preparing a liquid-phase dechlorinating agent, comprising the following steps:

[0052] 1) Prepare a 0.4 g / mL potassium carbonate aqueous solution, mix 30 g of the 0.4 g / mL potassium carbonate aqueous solution with 50 g of MCM-48 molecular sieve carrier (silicon-aluminum molar ratio of 50:1, specific surface area of ​​500 m 2 / g, pore size of 2.6 nm) to obtain a mixture;

[0053] 2) The mixture in step 1) was mixed with 20 g basic zinc carbonate, 20 g kaolin, 2.5 g sesbania powder, and 2.5 g sodium carboxymethyl cellulose powder, and an appropriate amount of water was added to reach an extrudable state, extruded into strips, dried at 120° C. for 2 h, and calcined at 490° C. for 2 h to obtain a dechlorination agent precursor;

[0054] 3) preparing a 0.005 g / mL tetramethylammonium nitrate aqueous solution, and immersing the dechlorinating agent precursor in 50 mL of the 0.005 g / mL tetramethylammonium nitrate aqueous solution at a temperature of 50° C. for 2 h. The dechlorinating agent was dried at 120° C. for 2 h to obtain the liquid dechlorinating agent.

[0055] Comparative Example 1

[0056] This comparative example provides a method for preparing a liquid-phase dechlorinating agent, comprising the following steps:

[0057] 1) Prepare a sodium carbonate aqueous solution with a concentration of 0.2 g / mL, and mix 30 g of the 0.2 g / mL sodium carbonate aqueous solution with 50 g of 13X molecular sieve carrier (silicon-aluminum molar ratio of 3:1, specific surface area of ​​650 m 2 / g, pore size of 1 nm) to obtain a mixture;

[0058] 2) The mixture in step 1) was mixed with 20 g of zinc oxide, 20 g of attapulgite, 2 g of sesbania powder, and 2 g of sodium carboxymethyl cellulose powder, and an appropriate amount of water was added to reach an extrudable state, extruded into strips, dried at 110° C. for 2 h, and calcined at 500° C. for 2 h to obtain a dechlorination agent precursor;

[0059] 3) preparing a 0.005 g / mL aqueous solution of tetramethylammonium bromide, and immersing the dechlorinating agent precursor in 50 mL of the 0.005 g / mL aqueous solution of tetramethylammonium bromide at a temperature of 30° C. for 2 h. The dechlorinating agent was dried at 100° C. for 3 h to obtain the liquid dechlorinating agent.

[0060] Comparative Example 2

[0061] This comparative example provides a method for preparing a liquid-phase dechlorinating agent, comprising the following steps:

[0062] 1) Prepare a sodium carbonate aqueous solution with a concentration of 0.2 g / mL, and mix 30 g of 0.2 g / mL sodium carbonate aqueous solution with 50 g of MCM-41 molecular sieve carrier (silicon-aluminum ratio of 25:1, specific surface area of ​​1000 m 2 / g, pore size of 4 nm) to obtain a mixture;

[0063] 2) The mixture in step 1) was mixed with 20 g of zinc oxide, 20 g of attapulgite, 2 g of sesbania powder, and 2 g of sodium carboxymethyl cellulose powder, and an appropriate amount of water was added to reach an extrudable state, extruded into strips, dried at 110° C. for 2 h, and calcined at 500° C. for 2 h to obtain the liquid dechlorination agent.

[0064] Comparative Example 3

[0065] This embodiment provides a method for preparing a liquid-phase dechlorinating agent, comprising the following steps:

[0066] 1) Prepare a sodium carbonate aqueous solution with a concentration of 0.2 g / mL, and mix 30 g of 0.2 g / mL sodium carbonate aqueous solution with 50 g of MCM-41 molecular sieve carrier (silicon-aluminum ratio of 25:1, specific surface area of ​​1000 m 2 / g, pore size of 4 nm) to obtain a mixture;

[0067] 2) The mixture in step 1) was mixed with 20 g of zinc oxide, 20 g of attapulgite, 2 g of sesbania powder, 2 g of sodium carboxymethyl cellulose powder, and 0.25 g of tetramethylammonium bromide, and an appropriate amount of water was added to reach an extrudable state, extruded into strips, dried at 110° C. for 2 h, and calcined at 500° C. for 2 h to obtain the liquid dechlorination agent.

[0068] Test Case

[0069] The evaluation experimental device adopts Beijing Xinhangdun XHD-3321 liquid phase dechlorination evaluation device.

[0070] The analytical instrument used is the German Jena 5100 chlorine content analyzer to detect the export organic chlorine and export inorganic chlorine.

[0071] Experimental conditions: reaction tube inner diameter 25 mm, catalyst particle size 20-40 mesh, loading volume 25 mL, temperature 50°C, pressure 1.0 MPa, test solution xylene, organic chlorine 1-chloropentane 5 mg / L, inorganic chlorine 5 mg / L hydrogen chloride, and evaluation was performed separately.

[0072] The performance of the dechlorination agent was evaluated based on the outlet organic chlorine and outlet inorganic chlorine, and the results are shown in Table 1.

[0073] Table 1

[0074]

[0075] As can be seen from the data comparison in Table 1 above, the liquid-phase dechlorination agent of the present invention has a very high removal efficiency for organic and inorganic chlorine. As can be seen from the data in the above table, the liquid-phase dechlorination agent provided by the present invention can significantly improve the removal performance of chlorides by using a mesoporous molecular sieve as a carrier, adding a transition metal as an active component, and impregnating a quaternary ammonium salt compound.

[0076] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A liquid phase dechlorination agent, characterized in that, The raw material components include the following parts by weight: 10-70 parts of mesoporous molecular sieve; 1-20 parts of an alkali metal compound; 10-30 parts of active ingredient; 0.1-5 parts of quaternary ammonium salt compound; 10-30 parts of binder; The mesoporous molecular sieve has a silicon to aluminum molar ratio of (10-100):1 and a specific surface area of ​​500-1000m 2 / g, pore size 2.6-10nm; The quaternary ammonium salt compound is at least one selected from tetramethylammonium hydroxide, tetramethylammonium nitrate, tetramethylammonium bromide, and tetrabutylammonium bromide; The mesoporous molecular sieve is at least one selected from MCM-41 molecular sieve, SBA-15 molecular sieve, and MCM-48 molecular sieve.

2. The liquid phase dechlorination agent according to claim 1, characterized in that The alkali metal compound is selected from at least one of potassium carbonate, potassium hydroxide, sodium carbonate, and sodium hydroxide; The active component is selected from at least one of zinc oxide, copper oxide, basic zinc carbonate, and basic copper carbonate; The binder is selected from at least one of sesbania powder, attapulgite, kaolin, silica sol, and sodium carboxymethyl cellulose.

3. A method for preparing a liquid-phase dechlorinating agent according to claim 1 or 2, characterized in that: The following steps are involved: 1) preparing an alkali metal compound into an alkali metal compound aqueous solution, and mixing the solution with a mesoporous molecular sieve to obtain a mixture; 2) mixing the mixture in step 1) with an active component and a binder, and forming, drying, and calcining to obtain a dechlorination agent precursor; 3) The quaternary ammonium salt compound is prepared into a quaternary ammonium salt compound aqueous solution, and then the dechlorination agent precursor is immersed in the quaternary ammonium salt compound aqueous solution, and dried to obtain the liquid phase dechlorination agent.

4. The preparation method of the liquid phase dechlorinating agent according to claim 3, characterized in that, The concentration of the alkali metal compound aqueous solution in step 1) is 0.1-1 g / mL; The mass ratio of the alkali metal compound aqueous solution to the mesoporous molecular sieve is 1:(1-10).

5. The method for preparing a liquid-phase dechlorinating agent according to claim 3 or 4, wherein: The forming in step 2) is extrusion forming, and the extrusion forming further includes the step of adding water; The drying temperature in step 2) is 100-120° C. and the drying time is 2-5 hours; The calcination temperature in step 2) is 200-500° C., and the calcination time is 2-4 hours.

6. The method for preparing a liquid-phase dechlorinating agent according to claim 3 or 4, wherein: The concentration of the quaternary ammonium salt aqueous solution in step 3) is 0.001-0.1 g / mL.

7. The method for preparing a liquid-phase dechlorinating agent according to claim 3 or 4, wherein: The immersion temperature in step 3) is 30-60° C. and the immersion time is 1-5 hours; The drying temperature in step 3) is 80-120° C., and the drying time is 2-6 hours.

8. Use of the liquid-phase dechlorinating agent according to any one of claims 1 or 2 or the liquid-phase dechlorinating agent prepared by the method according to any one of claims 3 to 7 in liquid-phase dechlorination of reformed oil.

9. Use of the liquid-phase dechlorinating agent according to any one of claims 1 or 2 or the liquid-phase dechlorinating agent prepared by the method according to any one of claims 3 to 7 in removing inorganic chlorine and organic chlorine.

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