Calcium-based reformate dechlorinating agent prepared from sodium metaaluminate as well as preparation method and application of calcium-based reformate dechlorinating agent

Abstract

The invention relates to the technical field of reformate dechlorinating agents and preparation processes, in particular to a calcium-based reformate dechlorinating agent prepared from sodium metaaluminate and a preparation method and application of the calcium-based reformate dechlorinating agent. According to the calcium-based reformate dechlorinating agent, sodium metaaluminate and soluble calcium salt are subjected to a co-precipitation reaction, active components are directly introduced, and the calcium-based reformate dechlorinating agent is obtained; aging, filtering, drying and roasting to obtain calcium-containing aluminum oxide powder, mixing the calcium-containing aluminum oxide powder with a bentonite binder, kneading, extruding into strips, drying and roasting to obtain the calcium-containing aluminum oxide composite material. The calcium-based dechlorinating agent for reformed oil is stable in structure, uniform in active center distribution, high in pore volume and specific surface area, and high in dechlorinating efficiency and dechlorinating precision in the liquid phase dechlorinating process; according to the calcium-based reformate dechlorinating agent disclosed by the invention, the production process steps are more simplified, the production cost is effectively reduced, and industrial production is easy to realize.

Description

Technical Field

[0001] This invention relates to the field of dechlorination agents for reformed oil and their preparation process. It is a method for preparing calcium-based dechlorination agents for reformed oil based on sodium aluminate, and also includes the calcium-based dechlorination agent for reformed oil prepared by the method, as well as the application of the calcium-based dechlorination agent for reformed oil in dechlorination. Background Technology

[0002] Catalytic reforming is a crucial production process in oil refining and petrochemicals. The main reaction involves converting cycloalkanes and alkanes into aromatics or isoalkanes using a bifunctional catalyst. Currently, catalytic reforming reactions utilize catalysts containing halogenated chlorine as the acidic component. In actual production, the chlorine content in the catalyst gradually decreases due to the influence of water and other substances in the reaction system. To ensure catalyst activity and achieve optimal water-chlorine balance, continuous injection of water and organic chlorides is necessary. During this process, some of the lost water and chlorine accumulates in the reformate. After fractionation in a stabilizer (or depentanizer), the reformate yields C3 and C4 fractions at the top and reformed gasoline (or depentanizer oil) at the bottom. The presence of even small amounts of chlorine in the reformate not only affects the quality of the top product but also causes corrosion in the downstream stabilizer system and extraction unit. Therefore, dechlorination of the reformate is essential.

[0003] Currently, solid dechlorinating agents are commonly used in industrial plants to remove hydrogen chloride from reformed oil. The dechlorination mechanism involves the active component in the dechlorinating agent reacting with HCl in an acid-base neutralization reaction to form stable metal chlorides, which are then fixed, thereby achieving the purpose of removing HCl. The active component is usually an oxide of an alkali metal or alkaline earth metal that can react with HCl. The active component is then mixed with a binder to form the dechlorinating agent, or it is prepared by loading the active component onto a carrier using an impregnation method. For example, patent application CN105542836A discloses a high-precision liquid-phase dechlorinating agent for reformed oil, composed of the following components: 5-20% CuO, 5-10% CaO, 4-8% KOH, and the balance being modified activated carbon. The preparation method involves impregnating the modified activated carbon in a Cu-Ca composite solution, then filtering, draining, and calcining. The calcined product is then impregnated in a KOH aqueous solution, filtered, and dried to obtain the dechlorinating agent. The resulting dechlorinating agent has a chlorine content of over 16% and a dechlorination accuracy of less than 0.5 ppm.

[0004] Patent application CN106268832A discloses a novel high-efficiency dechlorination agent and its preparation method. This dechlorination agent uses one or more of Na₂CO₃, CaCO₃, CaO, MgO, CuO, ZnO, and their derivatives as active components, NH₄HCO₃ as a pore-forming agent, and at least one of Al₂O₃, gibbsite, kaolin, or clay as a carrier and auxiliary agent. Modified Zn salt and Ca salt are added as synergistic agents. After mixing with an appropriate amount of water in a suitable ratio, the mixture is extruded into strips, dried, and calcined to produce the dechlorination agent. In China, dechlorination agents are mainly prepared by blending. The active components are mostly oxides, hydroxides and carbonates of alkali metals and alkaline earth metals such as Na2CO3, NaOH, NaHCO3, CaO and CaCO3. Some products use organic amines as active components. Meanwhile, the carriers are mostly inexpensive and readily available porous materials such as alumina, diatomaceous earth and clay, and organic and polymer additives are added. After mixing, molding, drying and calcining, dechlorination products are made.

[0005] For HCl in the liquid phase, the diffusion resistance is significantly greater than that of HCl molecules in the gas phase. Therefore, when preparing liquid-phase dechlorinating agents, in addition to considering the active component, the specific surface area and pore volume of the dechlorinating agent should be the primary considerations. When existing solid dechlorinating agents are used for liquid-phase dechlorination of reformed oils, the use of single-component alkali metal or alkaline earth metal oxides should be avoided for removing HCl from liquid oils. Binary metal oxides prepared by co-precipitation, after calcination, not only possess strong alkalinity but also have a much larger specific surface area and pore volume than the pure components. Currently, dechlorinating agents are typically made from oxides of alkali metals or alkaline earth metals. The active components are then mixed with a binder using a kneading method to form the dechlorinating agent, or the active components are loaded onto a carrier using an impregnation method. However, this method has several drawbacks: the raw materials are mostly powdery, requiring thorough pulverization before mixing, which leads to significant dust pollution; the dry powder mixture has poor flowability, making it difficult to mix evenly, and the material tends to clump and harden after adding water; product performance is inconsistent, with poor repeatability between different batches; and the active components are difficult to disperse evenly in the carrier. These issues result in low dechlorination efficiency, low dechlorination precision, high active component content, low mechanical strength, and low chlorine capacity in the dechlorinating agent. Therefore, improving the effective active components in reformed oil-liquid phase dechlorinating agents, improving the distribution of active components on the carrier, and refining the microstructure of the dechlorinating agent to enhance dechlorination efficiency and precision are problems that need to be addressed in this field. Summary of the Invention

[0006] This invention provides a method for preparing a calcium-based dechlorinating agent for reforming oil using sodium aluminate, and its application, overcoming the shortcomings of the prior art. The calcium-based dechlorinating agent for reforming oil prepared based on sodium aluminate has a large pore volume and chlorine solubility, and can achieve high dechlorination efficiency and precision when used for liquid-phase dechlorination of reforming oil.

[0007] One of the technical solutions of this invention is achieved through the following measures: a method for preparing a calcium-based reforming oil dechlorination agent, comprising the following steps: Step 1: Sodium aluminate solution and soluble calcium salt solution are mixed in a co-current flow. During the co-current mixing process, the sodium aluminate solution and soluble calcium salt solution undergo a co-precipitation reaction to obtain calcium-aluminum composite oxide. The temperature of the co-precipitation reaction is 45℃ to 85℃. Step 2: After aging the calcium-aluminum composite oxide for 2 to 6 hours, washing and filtering, drying at 120°C to 150°C for 2 to 4 hours, and calcining at 250°C to 500°C for 2 to 4 hours, calcium-containing alumina powder is obtained. The calcium-containing alumina powder contains activated alumina (γ-Al2O3), and the calcium hydroxide in the filter cake obtained by washing and filtration is uniformly distributed on the surface of the activated alumina as an alkaline active component.

[0008] Step 3: The calcium-containing alumina powder is mixed evenly with bentonite binder to form a mixture. The mixture is kneaded, extruded, dried at 120°C for 2 hours, and calcined at 250°C to 400°C for 2 to 4 hours to obtain a calcium-based reforming oil dechlorination agent.

[0009] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: In step 1 above, the preferred temperature for the coprecipitation reaction is 70°C to 75°C, and the endpoint of the coprecipitation reaction is a pH value of 12.5 to 12.8.

[0010] Before the coprecipitation reaction, sodium aluminate is prepared into a 10% to 20% aqueous solution, and soluble calcium salt is prepared into a 10% to 20% aqueous solution for later use.

[0011] In step 1 above, after adding soluble magnesium salt or soluble zinc salt to the soluble calcium salt solution, it is then mixed in parallel with the sodium aluminate solution. After adding soluble magnesium salt or soluble zinc salt, the resulting calcium-aluminum composite oxide also contains magnesium or zinc.

[0012] To further improve the chlorine capacity of the dechlorinating agent and enhance its surface activity and mechanical strength, Zn is introduced during the co-precipitation reaction of sodium aluminate solution and soluble calcium salt solution. 2+ or Mg 2+The precursors (calcium-aluminum composite oxides containing zinc or magnesium) prepared by co-precipitation have a stable hydrotalcite structure. The calcium-containing alumina powder obtained after calcination is a calcium-aluminum-magnesium composite or a calcium-aluminum-zinc composite. 2+ Ca 2+ or Mg 2+ Ca 2+ As a uniformly distributed alkaline active component, these complexes (i.e., calcium-aluminum-magnesium complexes or calcium-aluminum-zinc complexes) not only have strong alkalinity, but also large specific surface area and pore volume, and relatively high mechanical strength.

[0013] The soluble calcium salts mentioned above are calcium nitrate or calcium nitrate hydrate or calcium chloride; the soluble magnesium salts are magnesium nitrate or magnesium nitrate hydrate or magnesium chloride; and the soluble zinc salts are zinc nitrate or zinc nitrate hydrate.

[0014] When the soluble calcium salt is calcium chloride and the soluble magnesium salt is magnesium nitrate hydrate or magnesium chloride, the molar ratio of calcium chloride to magnesium nitrate hydrate or magnesium chloride is 1:(0.1 to 0.3); when the soluble calcium salt is calcium nitrate and the soluble magnesium salt is magnesium nitrate, the molar ratio of calcium nitrate to magnesium nitrate hydrate or magnesium nitrate is 1:(0.1 to 0.3); when the soluble calcium salt is calcium nitrate and the soluble zinc salt is zinc nitrate or zinc nitrate hydrate, the molar ratio of calcium nitrate to zinc nitrate or zinc nitrate hydrate is 1:(0.1 to 0.3).

[0015] In step 1 above, sodium aluminate solution and soluble calcium salt solution are mixed in parallel to form a reaction liquid. Activated carbon is added to the reaction liquid, and the amount of activated carbon added is 1% to 3% of the mass of calcium-containing alumina powder.

[0016] During the calcination process, activated carbon expands the volume of the substrate while reacting with some sodium nitrate to form sodium carbonate, which improves the uniformity and stability of the alkaline components loaded on the carrier.

[0017] In step 2 above, the roasting temperature is preferably 350°C to 400°C.

[0018] In step 2, drying is used to remove adsorbed water, and calcination is used to remove chemically bound water.

[0019] In step 2 above, the sodium nitrate content in the filter cake obtained from washing and filtration is controlled so that the mass percentage of sodium nitrite in the calcium-containing alumina powder generated by calcination is 2% to 6%.

[0020] The sodium nitrate content in the filter cake obtained by washing and filtering can be controlled by controlling the number of washing and filtering cycles.

[0021] When nitrate is used as one of the soluble calcium salt, soluble magnesium salt, and soluble zinc salt, sodium aluminate solution undergoes a co-precipitation reaction with nitrate, sodium nitrate is generated during the reaction. Sodium nitrate in the filter cake decomposes into nitrous acid during calcination, and sodium nitrite is uniformly distributed on the surface of active Al2O3 as an alkaline active component.

[0022] In step 3 above, the amount of bentonite binder added is 10% to 20% of the mixture; water-soluble starch is added to the mixture at a mass of 1% to 3% of the mixture mass; in step 3, the calcination temperature is preferably 300℃ to 350℃.

[0023] The bentonite binder is selected from sodium-based bentonite or calcium-based bentonite.

[0024] Water-soluble starch can improve the extrusion performance of calcium-containing alumina powder, and during the calcination process, it can continue to react with some sodium nitrite to generate sodium carbonate. Partial volatilization is beneficial to the pore expansion and volume expansion of the dechlorination agent.

[0025] The second technical solution of the present invention is achieved by the following measures: a calcium-based reforming oil dechlorinating agent prepared by the preparation method described in one of the technical solutions.

[0026] The following are further optimizations and / or improvements to the second technical solution of the above invention: The pore volume of the calcium-based reforming oil dechlorination agent described above is 0.23 cm³. 3 / g to 0.43cm 3 / g, chlorine capacity is 15.2% to 26.2% (mass percentage).

[0027] The third technical solution of the present invention is achieved through the following measures: the application of the calcium-based reforming oil dechlorination agent of the second technical solution in the dechlorination of reforming oil.

[0028] Compared with existing dechlorination agent preparation technologies using alumina as a carrier through kneading or impregnation, the calcium-based reforming oil dechlorination agent preparation method of the present invention has the following characteristics: (1) This invention utilizes sodium aluminate and soluble calcium salt to co-precipitate and directly introduce active components (such as sodium nitrite) to prepare dechlorination agent. This simplifies the original process of first preparing finished alumina and then impregnating and kneading it to produce dechlorination agent, effectively reducing production costs, making it easy to achieve industrial production, and reducing environmental pollution.

[0029] (2) In order to further improve the chlorine capacity of the dechlorinating agent, Zn is introduced in the co-precipitation step. 2+ or Mg 2+The precursors prepared by the co-precipitation method (i.e., calcium-aluminum composite oxides containing zinc or magnesium) have a stable hydrotalcite structure. The calcium-containing alumina powder obtained by calcination is a calcium-aluminum-magnesium composite or a calcium-aluminum-zinc composite. In the calcium-aluminum-magnesium composite, Na... + Ca 2+ Mg 2+ The alkaline active component is uniformly distributed. These complexes (calcium-aluminum-magnesium complexes or calcium-aluminum-zinc complexes) not only possess strong alkalinity but also have a large specific surface area and pore volume. The calcium-based reforming oil dechlorination agent prepared in this invention has a pore volume of 0.23 cm³. 3 / g to 0.43cm 3 / g, with a chlorine capacity of 15.2% to 26.2%.

[0030] (3) In this invention, activated carbon is added in the co-precipitation step; and water-soluble starch is added in the kneading and extrusion molding step. During the calcination process, activated carbon and water-soluble starch have the effects of expanding pores and increasing volume, while reacting with some sodium nitrate and sodium nitrite to generate sodium carbonate, thereby improving the uniformity and firmness of the alkaline components on the carrier.

[0031] In summary, the calcium-based reforming oil dechlorinating agent of the present invention has a stable structure, uniform distribution of active centers, high pore volume and specific surface area, and high dechlorination efficiency and precision in the liquid phase dechlorination process. The calcium-based reforming oil dechlorinating agent of the present invention has a simpler production process, effectively reduces production costs, and is easy to industrialize. Detailed Implementation

[0032] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0033] Unless otherwise specified, all chemical reagents and chemical products mentioned in this invention are known and commonly used chemical reagents and chemical products in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, and is generally defined as 25°C.

[0034] All raw materials used in the following examples are commercially available.

[0035] The specific surface area and pore size of the dechlorinating agents obtained in the following examples were tested according to the BET method.

[0036] The determination of chlorine content in the reformed oil used in the following examples before and after dechlorination was performed in accordance with SH / T 0977-2019.

[0037] The sodium-based or calcium-based bentonite used in the following examples has the following properties: absorbance ≥28%, gel value ≥300ml / 15g, water absorption rate ≥150%, fineness (325 mesh) ≥80%, and moisture content ≤11%.

[0038] The activated carbon used in the following examples has a particle size of 300 mesh and a methylene blue decolorization power of ≥11 ml / 0.1g.

[0039] The present invention will be further described below with reference to embodiments: Example 1 163.9 g of solid sodium aluminate (NaAlO2) was dissolved in 1200 ml of deionized water to obtain a sodium aluminate solution; 236.5 g of Ca(NO3)2·4H2O was dissolved in 1100 ml of deionized water to obtain a calcium nitrate solution; 200 ml of deionized water was added to a three-necked flask with a stirrer as the base solution. The sodium aluminate solution and calcium nitrate solution were added to the three-necked flask, and the mixture was stirred and flowed concurrently at 70 °C. A co-precipitation reaction occurred between the sodium aluminate solution and the calcium nitrate solution, which was completed in 1 hour. The pH value of the co-precipitation reaction was 12.5 to 12.8, which was the endpoint. The mixture was aged for 6 hours, washed, and filtered. The filter cake was dried at 120 °C for 2 hours, calcined in a muffle furnace at 400 °C for 4 hours, and then cooled to obtain calcium-containing alumina powder. The above-mentioned alumina powder (35.0g) and sodium-based bentonite (7.0g) were kneaded with deionized water, extruded into strips, dried at 120℃ for 2h, and calcined at 280℃ for 4h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 1.

[0040] Example 2 163.9 g of solid sodium aluminate (NaAlO2) was dissolved in 1200 ml of deionized water to obtain a sodium aluminate solution; 111.5 g of CaCl2 was dissolved in 1000 ml of deionized water to obtain a calcium chloride solution; 200 ml of deionized water was added to a three-necked flask with a stirrer as the base solution. The sodium aluminate solution and calcium chloride solution were added to the three-necked flask, and the mixture was stirred and flowed concurrently at 70 °C. A co-precipitation reaction occurred between the sodium aluminate solution and the calcium chloride solution, which was completed within 1 hour. The pH value of the co-precipitation reaction was 12.5 to 12.8, which was the endpoint. The mixture was aged for 6 hours, washed, and filtered. The filter cake was dried at 120 °C for 2 hours, calcined in a muffle furnace at 400 °C for 4 hours, and cooled to obtain calcium-containing alumina powder. The above-mentioned calcium-containing alumina powder (35.0g) and sodium-based bentonite (7.0g) were kneaded with deionized water, extruded into strips, dried at 120℃ for 2h, and calcined at 280℃ for 4h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 2.

[0041] Example 3 The difference between this embodiment and Example 1 is that, during the co-precipitation reaction, 3.1g of 300-mesh activated carbon was added to the bottom liquid, the filter cake was dried at 120°C for 2 hours, calcined at 400°C in a muffle furnace for 2 hours, and cooled to obtain calcium-containing alumina powder, in which the sodium ion content was 1.8% (mass percentage). The above-mentioned calcium-containing alumina powder (37.5g) and sodium-based bentonite (4.0g) were kneaded with deionized water, extruded into strips, dried at 120℃ for 2h, and calcined at 300℃ for 2h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 3.

[0042] Example 4 163.9 g of solid sodium aluminate (NaAlO2) was dissolved in 1200 ml of deionized water to obtain a sodium aluminate solution. 166.0 g of Ca(NO3)2·4H2O and 179.4 g of Zn(NO3)2·6H2O were dissolved in 1100 ml of deionized water to obtain a mixed solution of calcium nitrate and zinc nitrate. 200 ml of deionized water was added to a stirred three-necked flask as a base solution. The sodium aluminate solution and the mixed solution of calcium nitrate and zinc nitrate were added to the three-necked flask. The mixture was stirred and flowed concurrently at 75 °C. A co-precipitation reaction occurred between the sodium aluminate solution and the calcium nitrate solution, which was completed within 1 hour. The pH value reached 12.5 to 12.8, marking the endpoint of the co-precipitation reaction. The mixture was aged for 2 hours, washed, and filtered. The filter cake was dried at 150 °C for 2 hours, calcined in a muffle furnace at 400 °C for 4 hours, and then cooled to obtain calcium-containing alumina powder (i.e., a calcium-aluminum-zinc composite). The above-mentioned calcium-aluminum-zinc complex 35.0g and sodium-based bentonite 7.0g were kneaded with deionized water, extruded into strips, dried at 120℃ for 2h, and calcined at 300℃ for 4h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 4.

[0043] Example 5 The difference between this embodiment and Example 4 is that, during the co-precipitation reaction, 2.2g of 300-mesh activated carbon was added to the bottom solution, the filter cake was dried at 120℃ for 2 hours, calcined in a muffle furnace at 350℃ for 2 hours, and cooled to obtain calcium-containing alumina powder. In the calcium-containing alumina powder, Na... + Content 1.2% (by mass).

[0044] The above-mentioned calcium-containing alumina powder (37.5g), sodium-based bentonite (5.6g), and water-soluble starch (0.5g) were mixed with deionized water, kneaded, extruded, dried at 120℃ for 2h, and calcined at 300℃ for 2h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 5.

[0045] Example 6 163.9 g of solid sodium aluminate (NaAlO2) was dissolved in 1200 ml of deionized water to obtain a sodium aluminate solution; 189.2 g of Ca(NO3)2·4H2O and 51.3 g (0.2 mol.) of Mg(NO3)2·6H2O were dissolved in 1100 ml of deionized water to obtain a mixed solution of calcium nitrate and magnesium nitrate. 200 ml of deionized water was added to a stirred three-necked flask as a base solution. The sodium aluminate solution and the mixed solution of calcium nitrate and magnesium nitrate were added to the three-necked flask. The mixture was stirred and flowed concurrently at 85 °C. A co-precipitation reaction occurred between the sodium aluminate solution and the calcium nitrate solution, which was completed within 1 hour. The pH value reached 12.5 to 12.8, which was the endpoint of the co-precipitation reaction. After aging for 6 hours, the mixture was washed with hot water at approximately 65 °C and filtered to obtain a filter cake. The filter cake was dried at 120℃ for 2 hours, calcined in a muffle furnace at 400℃ for 4 hours, and cooled to obtain calcium-containing alumina powder (i.e., calcium-aluminum-magnesium composite). The above-mentioned calcium-aluminum-magnesium complex 35.0g and sodium-based bentonite 7.0g were kneaded with deionized water, extruded into strips, dried at 120℃ for 2h, and calcined at 280℃ for 4h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 6.

[0046] Example 7 163.9 g of solid sodium aluminate (NaAlO2) was dissolved in 1200 ml of deionized water to obtain a sodium aluminate solution; 99.9 g of CaCl2 and 9.5 g of MgCl2 were dissolved in 1000 ml of deionized water to obtain a mixed solution of calcium chloride and magnesium chloride. 200 ml of deionized water was added to a stirred three-necked flask as a base solution. The sodium aluminate solution and the mixed solution of calcium chloride and magnesium chloride were added to the three-necked flask, and the reaction was carried out at 85 °C with stirring and in a parallel flow for 1 hour. The pH value reached 12.5 to 12.8, which was the endpoint of the coprecipitation reaction. The mixture was aged for 4 hours, washed with hot water at approximately 60 °C, and filtered to obtain a filter cake. The filter cake was dried at 120 °C for 4 hours, calcined in a muffle furnace at 350 °C for 4 hours, and cooled to obtain a calcium-aluminum-magnesium complex. The above-mentioned calcium-aluminum-magnesium complex 35.0g and sodium-based bentonite 4.0g were kneaded with deionized water, extruded into strips, dried at 120℃ for 2h, and calcined at 280℃ for 4h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 7.

[0047] Example 8 163.9 g of solid sodium aluminate (NaAlO2) was dissolved in 1200 ml of deionized water to obtain a sodium aluminate solution; 99.9 g of CaCl2 and 9.5 g of MgCl2 were dissolved in 1000 ml of deionized water to obtain a mixed solution of calcium chloride and magnesium chloride. 200 ml of deionized water was added to a stirred three-necked flask as a base solution. The sodium aluminate solution and the mixed solution of calcium chloride and magnesium chloride were added to the three-necked flask, and the reaction was carried out at 85 °C with stirring and in a parallel flow for 1 hour. The pH value reached 12.5 to 12.8, which was the endpoint of the coprecipitation reaction. The mixture was aged for 4 hours, washed with hot water at approximately 60 °C, and filtered to obtain a filter cake. The filter cake was dried at 150 °C for 2 hours, calcined in a muffle furnace at 350 °C for 4 hours, and cooled to obtain a calcium-aluminum-magnesium complex. The above-mentioned calcium-aluminum-magnesium complex 35.0g and sodium-based bentonite 4.0g were kneaded with deionized water, extruded into strips, dried at 120℃ for 2h, and calcined at 350℃ for 4h to obtain a calcium-based reforming oil dechlorinating agent, referred to as dechlorinating agent 8.

[0048] The activity of the calcium-based reforming oil dechlorinating agents prepared in Examples 1 to 8 above was evaluated: The present invention provides a method for evaluating the dechlorination activity of a calcium-based reforming oil dechlorinating agent: A 20-40 mesh calcium-based reforming oil dechlorinating agent is packed into an adsorption column with an inner diameter of 8 mm, a height-to-diameter ratio of 8:1, a temperature of 45°C, and a pressure of 0.4 MPa. The reforming oil, with a chlorine content of approximately 5 mg / kg, is then subjected to a liquid hourly space velocity (LHSV) of 4 h⁻¹. -1 The (volume) enters the adsorption column (top in, bottom out), and the chlorine content in the outflowing reformed oil is measured. When the chlorine content is greater than 0.5 mg / kg, it can be considered breakthrough, and the reaction time is recorded. A longer dechlorination time indicates better dechlorination activity.

[0049] The present invention relates to a method for evaluating the chlorine capacity of a calcium-based reforming oil dechlorinating agent: A 20-40 mesh calcium-based reforming oil dechlorinating agent is packed into an adsorption column with an inner diameter of 8 mm, a height-to-diameter ratio of 8:1, at room temperature and atmospheric pressure. The flow rate of N2 containing 0.1% HCl is controlled by a flow meter, and the space velocity is 1000 h⁻¹. -1 The feed gas enters the adsorption column, passing through the bed from top to bottom and reacting with the packing material. The experiment is considered complete when the outlet HCl concentration reaches 0.5 mg / kg. After the experiment, the calcium-based reforming oil dechlorinator is removed and subjected to chlorine capacity analysis. The breakthrough chlorine capacity (Cl%) of the dechlorinator refers to the chlorine content per unit mass of dechlorinator when 0.5 mg / kg HCl is detected in the tail gas of the evaluation system. The formula for calculating the breakthrough chlorine capacity is as follows: Cl% = mchlorine / mdechlorinating agent × 100% In the formula, mchlorine is the mass of chlorine, and mdechlorinator is the mass of the dechlorinator in the calcium-based reforming oil.

[0050] As shown in Table 1, the dechlorinating agents prepared in Examples 1 to 8 have large specific surface areas and pore volumes. In particular, the dechlorinating agent prepared in Example 3 has a chlorine capacity of 26.2%, and the dechlorinating agent prepared in Example 5 has a pore volume of 0.43 cm³. 3 / g, with a penetration time of 42h.

[0051] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for preparing a calcium-based reforming oil dechlorination agent, characterized in that, Includes the following steps: Step 1: Sodium aluminate solution and soluble calcium salt solution are mixed in a co-current flow. During the co-current mixing process, the sodium aluminate solution and soluble calcium salt solution undergo a co-precipitation reaction to obtain calcium-aluminum composite oxide. The temperature of the co-precipitation reaction is 45℃ to 85℃. Step 2: After aging the calcium-aluminum composite oxide for 2 to 6 hours, washing and filtering, drying at 120°C to 150°C for 2 to 4 hours, and calcining at 250°C to 500°C for 2 to 4 hours, calcium-containing alumina powder is obtained. Step 3: The calcium-containing alumina powder is mixed evenly with bentonite binder to form a mixture. The mixture is kneaded, extruded, dried at 120°C for 2 hours, and calcined at 250°C to 400°C for 2 to 4 hours to obtain a calcium-based reforming oil dechlorination agent.

2. The preparation method according to claim 1, characterized in that, In step 1, the temperature of the coprecipitation reaction is preferably 70°C to 75°C, and the endpoint of the coprecipitation reaction is a pH value of 12.5 to 12.8; or / and, in step 1, the sodium aluminate solution and the soluble calcium salt solution are mixed in parallel to form a reaction liquid, and activated carbon is added to the reaction liquid, the amount of activated carbon added being 1% to 3% of the mass of the calcium alumina powder.

3. The preparation method according to claim 1 or 2, characterized in that... In step 1, after adding soluble magnesium salt or soluble zinc salt to the soluble calcium salt solution, it is then mixed in parallel with the sodium aluminate solution. After adding soluble magnesium salt or soluble zinc salt, the resulting calcium-aluminum composite oxide also contains magnesium or zinc.

4. The preparation method according to claim 3, characterized in that, Soluble calcium salts are made of calcium nitrate or calcium nitrate hydrate or calcium chloride; soluble magnesium salts are made of magnesium nitrate or magnesium nitrate hydrate or magnesium chloride; soluble zinc salts are made of zinc nitrate or zinc nitrate hydrate.

5. The preparation method according to claim 4, characterized in that, When calcium chloride is used as the soluble calcium salt and magnesium nitrate hydrate or magnesium chloride is used as the soluble magnesium salt, the molar ratio of calcium chloride to magnesium nitrate hydrate or magnesium chloride is 1:(0.1 to 0.3); or, when calcium nitrate is used as the soluble calcium salt and magnesium nitrate is used as the soluble magnesium salt, the molar ratio of calcium nitrate to magnesium nitrate hydrate or magnesium nitrate is 1:(0.1 to 0.3); or, when calcium nitrate is used as the soluble calcium salt and zinc nitrate or zinc nitrate hydrate is used as the soluble zinc salt, the molar ratio of calcium nitrate to zinc nitrate or zinc nitrate hydrate is 1:(0.1 to 0.3).

6. The preparation method according to any one of claims 1 to 5, characterized in that... In step 2, the calcination temperature is preferably 350°C to 400°C; or / and, in step 2, the sodium nitrate content in the filter cake obtained by washing and filtration is controlled so that the mass percentage of sodium nitrite in the calcium-containing alumina powder generated by calcination is 2% to 6%.

7. The preparation method according to any one of claims 1 to 6, characterized in that... In step 3, the amount of bentonite binder added is 10% to 20% of the mixture, and the bentonite binder is selected from sodium-based bentonite or calcium-based bentonite; or / and, in step 3, water-soluble starch is added to the mixture at a mass of 1% to 3% of the mixture; or / and, in step 3, the calcination temperature is preferably 300°C to 350°C.

8. A calcium-based reforming oil dechlorinating agent prepared by the preparation method according to any one of claims 1 to 7.

9. The calcium-based reforming oil dechlorination agent according to claim 8, characterized in that, The pore volume is 0.23 cm. 3 / g to 0.43cm 3 / g, with a chlorine capacity of 15.2% to 26.2%.

10. The application of the calcium-based reforming oil dechlorinating agent as described in claim 8 or 9 in the dechlorination of reforming oil.

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