Dechlorinating agent as well as preparation method and application thereof

Abstract

The invention provides a dechlorinating agent as well as a preparation method and application thereof, and the dechlorinating agent comprises the following components in percentage by mass: 20-55% of calcium oxide, 10-30% of zinc oxide, 15-40% of aluminum oxide and the balance of an adhesive. The preparation method sequentially comprises the following steps: preparing materials, stirring, mixing and grinding, extruding into strips, drying, activating and sieving. The reformate liquid-phase dechlorinating agent common in the market can remove total chlorine in the reformate to be smaller than or equal to 0.5 ppm and the chlorine capacity is larger than or equal to 10%, the dechlorinating agent provided by the invention can efficiently remove organic chlorine and hydrogen chloride in the reformate, compared with the reformate liquid-phase dechlorinating agent in the market, the chlorine capacity is improved by 20%, the preparation cost can be reduced, the service life is prolonged, the agent replacement frequency is reduced, and the production cost is reduced. And large-scale popularization and application are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry and relates to a dechlorinating agent, in particular to a dechlorinating agent and a preparation method and application thereof. Background Art

[0002] In the reforming oil, the hazards of chlorine are mainly divided into three types: corrosion to catalytic reforming equipment, ammonium salt blockage and catalyst poisoning. Among them, the corrosion to the equipment is mainly concentrated on the top of the depentanizer tower and its condensation system of the catalytic reforming unit; the production of ammonium salts will not only destroy the stable operation of the distillation tower, but also easily cause ammonium salt crystallization in the low-temperature part of the heat exchanger, causing blockage of equipment and pipelines, and forming under-scale corrosion at the ammonium salt coverage, thereby affecting the normal operation of the catalytic reforming equipment. At present, some reforming units in operation in China will encounter problems such as short life of liquid phase dechlorinating agent, salt formation or corrosion of stabilization tower, and salt formation or corrosion of downstream equipment (such as air cooler), which significantly increases the maintenance cost of the equipment and restricts the stable operation of the reforming unit.

[0003] Existing dechlorinators mainly include physical adsorption, chemical adsorption, and a combination of physical and chemical adsorption. Among them, physical adsorption dechlorinators are mainly prepared by using activated alumina, molecular sieves, activated carbon, etc. with large specific surface areas, and remove organic chlorine and part of hydrogen chloride by physical adsorption, such as the PCL-100 molecular sieve type liquid phase dechlorinator produced by UOP. Chemical adsorption dechlorinators are mainly prepared by using alkaline metal oxides (such as calcium oxide, magnesium oxide, zinc oxide, etc.), and the alkaline metal oxides react with hydrogen chloride to generate corresponding salts fixed in the dechlorinator to achieve removal. This type of dechlorinator mainly removes hydrogen chloride, and the removal efficiency is more than 80% (the chlorine content in the oil is 1ug / g), while the removal effect on organic chlorine is limited, generally only 10-20% (the chlorine content in the oil is 1ug / g). In addition, the dechlorinator prepared by using activated carbon to load alkaline oxides has both physical and chemical adsorption functions, but faces the defects of high preparation cost, limited mission life, and high frequency of agent replacement, and there is still a lot of room for improvement. The common liquid phase dechlorination agents for reforming oil currently available on the market can remove the total chlorine in the reforming oil to ≤0.5ppm and the chlorine capacity ≥10%.

[0004] It can be seen that how to provide a dechlorinating agent and a preparation method thereof to achieve efficient removal of organic chlorine and hydrogen chloride while reducing preparation costs, extending service life, and reducing the frequency of agent replacement has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a dechlorinating agent and a preparation method and application thereof. The dechlorinating agent can efficiently remove organic chlorine and hydrogen chloride in reforming oil, and the chlorine capacity is increased by 20% compared with the liquid phase dechlorinating agent of reforming oil on the market, and the preparation cost is reduced, the service life is extended, and the frequency of agent replacement is reduced, which is conducive to large-scale promotion and application.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a dechlorinating agent, which comprises the following components by mass percentage:

[0008] Calcium oxide 20-55%;

[0009] Zinc oxide 10-30%;

[0010] Alumina 15-40%;

[0011] The balance is adhesive.

[0012] In the present invention, the mass percentage of calcium oxide is 20-55%, for example, it can be 20%, 25%, 30%, 35%, 40%, 45%, 50% or 55%, and more preferably 25-50%; the mass percentage of zinc oxide is 10-30%, for example, it can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, and more preferably 15-25%; the mass percentage of aluminum oxide is 15-40%, for example, it can be 15%, 20%, 25%, 30%, 35% or 40%, and more preferably 20-35%, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0013] The present invention adopts special alkaline metal oxides (calcium oxide, zinc oxide) and high-activity alumina as effective components of the dechlorinating agent, wherein the calcium oxide and zinc oxide can react with hydrogen chloride to generate corresponding chloride salts, thereby effectively removing hydrogen chloride, and helping to promote the adsorption and dechlorination process of organic chlorine, reducing corrosion and blockage of equipment; the high-activity alumina has a strong adsorption capacity due to its porous structure, and can effectively adsorb hydrogen chloride and organic chlorine. In the dechlorination process, the alumina not only participates in the chemical reaction, but also provides a physical adsorption platform. The coordinated use of these special alkaline metal oxides and high-activity alumina significantly improves the dechlorination efficiency and chlorine capacity of the dechlorinating agent, and the chlorine capacity is increased by 20% compared with the market reformed oil liquid phase dechlorinating agent, while fully reducing the preparation cost, extending the service life, reducing the frequency of agent replacement, and saving a large amount of dechlorinating agent procurement costs for enterprises.

[0014] Preferably, the specific surface area of ​​the alumina is 250-350m2 / g, for example, it can be 250m 2 / g, 260m 2 / g, 270m 2 / g, 280m 2 / g, 290m 2 / g、300m 2 / g, 310m 2 / g, 320m 2 / g, 330m 2 / g, 340m 2 / g or 350m 2 / g, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0015] In the present invention, the alumina with a high specific surface area has strong physical and chemical adsorption capabilities, which helps to further improve the chlorine capacity of the dechlorination agent.

[0016] Preferably, the binder comprises any one of sesbania powder, kaolin, montmorillonite, sodium carboxymethyl cellulose or polysorbate, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of sesbania powder and kaolin, a combination of kaolin and montmorillonite, a combination of montmorillonite and sodium carboxymethyl cellulose, or a combination of sodium carboxymethyl cellulose and polysorbate.

[0017] In a second aspect, the present invention provides a method for preparing the dechlorinating agent as described in the first aspect, the preparation method comprising sequentially performing material preparation, mixing, co-grinding, extrusion, drying, activation and screening.

[0018] Preferably, the material preparation includes preparing zinc oxide, specifically comprising: calcining zinc carbonate and chemically decomposing it to obtain zinc oxide.

[0019] Preferably, the roasting treatment is carried out in a rotary kiln, and the kiln head temperature is 120-320°C, for example, it can be 120°C, 140°C, 160°C, 180°C, 200°C, 220°C, 240°C, 260°C, 280°C, 300°C or 320°C, and the kiln tail temperature is 250-480°C, for example, it can be 250°C, 300°C, 350°C, 400°C, 450°C or 480°C, but it is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0020] Preferably, the loss on ignition of the roasting treatment is 2-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the mixing comprises: mixing calcium hydroxide, zinc oxide and aluminum oxide according to a set mass percentage and stirring evenly.

[0022] Preferably, the mixing further comprises adding a binder.

[0023] The present invention can significantly enhance the binding force between the raw materials of the dechlorinating agent by adding an adhesive during the preparation process of the dechlorinating agent, which is helpful for the molding of the dechlorinating agent, and at the same time improves the mechanical strength of the dechlorinating agent, avoids the dechlorinating agent from being broken during transportation, filling and reaction, and prolongs the service life of the dechlorinating agent.

[0024] Preferably, the mixing and grinding time is 20-40 min, for example, it can be 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min or 40 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the diameter of the extruded strip is 3-5 mm, for example, it can be 3 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, 4 mm, 4.2 mm, 4.4 mm, 4.6 mm, 4.8 mm or 5 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] Preferably, the drying temperature is 60-100°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C or 100°C, and the time is 6-10h, for example, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h or 10h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the activation temperature is 300-380°C, for example, it can be 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C or 380°C, and the time is 2-4h, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h or 4h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] The present invention specifically limits the activation temperature of the dechlorinating agent within the range of 300-380° C., which is helpful to fully remove volatile impurities in the dechlorinating agent, thereby forming more microporous structures, increasing the specific surface area of ​​the dechlorinating agent, and avoiding adverse phase changes or structural damage caused by excessively high temperatures, maintaining the effectiveness of active components in the dechlorinating agent and the overall mechanical strength, and improving its durability and stability in industrial applications.

[0029] Preferably, the mesh size of the sieving is 4-40 mesh, for example, it can be 4 mesh, 6 mesh, 8 mesh, 10 mesh, 15 mesh, 20 mesh, 25 mesh, 30 mesh, 35 mesh or 40 mesh, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] As a preferred technical solution of the second aspect of the present invention, the preparation method comprises the following steps: material preparation, mixing, co-grinding, extrusion, drying, activation and screening.

[0031] The material preparation includes preparing zinc oxide, specifically including: calcining zinc carbonate in a rotary kiln, controlling the temperature at the kiln head to 120-320°C, the temperature at the kiln tail to 250-480°C, the ignition loss to 2-10%, and obtaining zinc oxide after chemical decomposition; the mixing includes: mixing calcium hydroxide, zinc oxide and aluminum oxide according to a set mass percentage, adding a binder and stirring evenly; the mixing and rolling time is 20-40 minutes; the diameter of the extruded strips is 3-5mm; the drying temperature is 60-100°C, the time is 6-10h; the activation temperature is 300-380°C, the time is 2-4h; the sieving mesh size is 4-40 meshes.

[0032] In a third aspect, the present invention provides an application of the dechlorinating agent as described in the first aspect, wherein the dechlorinating agent is used to remove organic chlorine and hydrogen chloride in reformed oil.

[0033] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0034] The system refers to an equipment system, a device system or a production device.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention adopts special alkaline metal oxides (calcium oxide, zinc oxide) and high-activity alumina as effective components of the dechlorinating agent, wherein the calcium oxide and zinc oxide can react with hydrogen chloride to generate corresponding chloride salts, thereby effectively removing hydrogen chloride, and helping to promote the adsorption and dechlorination process of organic chlorine, reducing corrosion and blockage of equipment; the high-activity alumina has a strong adsorption capacity due to its porous structure, and can effectively adsorb hydrogen chloride and organic chlorine. In the dechlorination process, the alumina not only participates in the chemical reaction, but also provides a physical adsorption platform. The coordinated use of these special alkaline metal oxides and high-activity alumina significantly improves the dechlorination efficiency and chlorine capacity of the dechlorinating agent, and the chlorine capacity is increased by 20% compared with the market reformed oil liquid phase dechlorinating agent, while fully reducing the preparation cost, extending the service life, reducing the frequency of agent replacement, and saving a large amount of dechlorinating agent procurement costs for enterprises. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further illustrated below through specific implementation methods.

[0038] Example 1

[0039] This embodiment provides a dechlorinating agent and a preparation method thereof. The dechlorinating agent comprises, by mass percentage, 50% calcium hydroxide, 25% zinc oxide and 20% aluminum oxide, and the remainder is a binder (sesbania powder). The specific surface area of ​​the aluminum oxide is 320 m 2 / g.

[0040] The preparation method provided in this embodiment includes the following steps: material preparation, mixing, co-grinding, extrusion, drying, activation and screening. The material preparation includes the preparation of zinc oxide, specifically including: calcining zinc carbonate in a rotary kiln, controlling the kiln head temperature to 220°C, the kiln tail temperature to 360°C, and the ignition loss to 6%, and obtaining zinc oxide after chemical decomposition; the mixing includes: mixing calcium hydroxide, zinc oxide and aluminum oxide according to the set mass percentage, adding field sesbania powder as a binder and stirring evenly; the co-grinding time is 30 minutes; the extrusion diameter is 4 mm; the drying temperature is 80°C and the time is 8 hours; the activation temperature is 340°C and the time is 3 hours; the sieving mesh size is 20 meshes.

[0041] Example 2

[0042] This embodiment provides a dechlorinating agent and a preparation method thereof. The dechlorinating agent comprises, by mass percentage, 25% calcium hydroxide, 25% zinc oxide and 35% aluminum oxide, and the remainder is a binder (kaolin). The specific surface area of ​​the aluminum oxide is 250 m 2 / g.

[0043] The preparation method provided in this embodiment includes the following steps: material preparation, mixing, co-grinding, extrusion, drying, activation and screening. The material preparation includes the preparation of zinc oxide, which specifically includes: calcining zinc carbonate in a rotary kiln, and controlling the temperature at the kiln head to 120°C, the temperature at the kiln tail to 250°C, and the loss on ignition to 2%, and obtaining zinc oxide after chemical decomposition; the mixing includes: mixing calcium hydroxide, zinc oxide and aluminum oxide according to the set mass percentage, and adding kaolin as a binder and stirring evenly; the co-grinding time is 20 minutes; the diameter of the extruded strip is 5 mm; the drying temperature is 60°C and the time is 10 hours; the activation temperature is 300°C and the time is 4 hours; the sieving mesh is 4 meshes.

[0044] Example 3

[0045] This embodiment provides a dechlorinating agent and a preparation method thereof. The dechlorinating agent comprises, by mass percentage, 40% calcium hydroxide, 15% zinc oxide and 40% aluminum oxide, and the remainder is a binder (montmorillonite). The specific surface area of ​​the aluminum oxide is 350 m 2 / g.

[0046] The preparation method provided in this embodiment includes material preparation, mixing, co-grinding, extrusion, drying, activation and screening in sequence. The material preparation includes the preparation of zinc oxide, specifically including: calcining zinc carbonate in a rotary kiln, and controlling the temperature at the kiln head to 320°C, the temperature at the kiln tail to 480°C, and the loss on ignition to 10%, and obtaining zinc oxide after chemical decomposition; the mixing includes: mixing calcium hydroxide, zinc oxide and aluminum oxide according to the set mass percentage, adding montmorillonite as a binder and stirring evenly; the co-grinding time is 40 minutes; the diameter of the extruded strip is 3 mm; the drying temperature is 100°C and the time is 6 hours; the activation temperature is 380°C and the time is 2 hours; the mesh number of the sieving is 40 meshes.

[0047] Example 4

[0048] This embodiment provides a dechlorinating agent and a preparation method thereof. Except that the mass percentage of calcium hydroxide is changed to 55%, the mass percentage of zinc oxide is changed to 20%, and the mass percentage of aluminum oxide is changed to 15%, the other conditions are the same as those in Example 1, and thus are not described in detail here.

[0049] Example 5

[0050] This embodiment provides a dechlorinating agent and a preparation method thereof. Except that the mass percentage of calcium hydroxide is changed to 20%, the mass percentage of zinc oxide is changed to 30%, and the mass percentage of aluminum oxide is changed to 40%, the other conditions are the same as those in Example 1, and thus are not described in detail here.

[0051] Example 6

[0052] This embodiment provides a dechlorinating agent and a preparation method thereof, except that the specific surface area of ​​alumina is changed to 200m 2 / g, and the other conditions are the same as those in Example 1, so they are not described here in detail.

[0053] Example 7

[0054] This embodiment provides a dechlorinating agent and a preparation method thereof. Except that the activation temperature is lowered to 250° C., other conditions are the same as those in Embodiment 1, and thus are not described in detail herein.

[0055] Example 8

[0056] This embodiment provides a dechlorinating agent and a preparation method thereof. Except that the activation temperature is increased to 400° C., other conditions are the same as those in Embodiment 1, and thus will not be described in detail herein.

[0057] Comparative Example 1

[0058] This comparative example provides a dechlorinating agent and a preparation method thereof. Except that the mass percentage of calcium oxide is changed to 60%, the mass percentage of zinc oxide is changed to 10%, and the mass percentage of aluminum oxide is changed to 10%, the other conditions are the same as those in Example 1, and thus are not described in detail here.

[0059] Comparative Example 2

[0060] This comparative example provides a dechlorinating agent and a preparation method thereof. Except that the mass percentage of calcium oxide is changed to 15%, the mass percentage of zinc oxide is changed to 30%, and the mass percentage of aluminum oxide is changed to 45%, the other conditions are the same as those in Example 1, so they are not described here.

[0061] Comparative Example 3

[0062] This comparative example provides a dechlorinating agent and a preparation method thereof, except that calcium oxide is not added, and the mass percentage of zinc oxide is changed to 50%, and the mass percentage of aluminum oxide is changed to 45%. The other conditions are the same as those in Example 1, so they are not described here.

[0063] Comparative Example 4

[0064] This comparative example provides a dechlorinating agent and a preparation method thereof, except that zinc oxide is not added, and the mass percentage of calcium oxide is changed to 65%, and the mass percentage of aluminum oxide is changed to 30%. The other conditions are the same as those in Example 1, so they are not described here.

[0065] Performance Testing

[0066] The dechlorinating agents provided in Examples 1-8 and Comparative Examples 1-4 were used to remove organic chlorine and hydrogen chloride from the reforming oil. The specific operation was as follows: the dechlorinating agent was loaded into a micro-reactor tube, and the reforming oil containing hydrogen chloride and organic chlorine was introduced. The relevant process conditions were as follows:

[0067]

[0068] The chlorine content of the purified oil was analyzed, and the bulk density, abrasion rate, penetration chlorine capacity and radial crushing resistance of the dechlorination agents obtained in the embodiments and comparative examples were tested, and the relevant results are shown in Table 1 below.

[0069] Table 1

[0070]

[0071] In the above table, the tests of bulk density, abrasion rate, penetration chlorine capacity and radial crushing resistance were all carried out with reference to the Q / 320583YH005-2022 standard.

[0072] It can be seen that the present invention adopts special alkaline metal oxides (calcium oxide, zinc oxide) and high-activity alumina as the effective ingredients of the dechlorinating agent, wherein the calcium oxide and zinc oxide can react with hydrogen chloride to generate corresponding chloride salts, thereby effectively removing hydrogen chloride, and helping to promote the adsorption and dechlorination process of organic chlorine, reducing the corrosion and blockage of equipment; the high-activity alumina has a strong adsorption capacity due to its porous structure, and can effectively adsorb hydrogen chloride and organic chlorine. In the dechlorination process, alumina not only participates in chemical reactions, but also provides a physical adsorption platform. The coordinated use of these special alkaline metal oxides and high-activity alumina significantly improves the dechlorination efficiency and chlorine capacity of the dechlorinating agent, and the chlorine capacity is increased by 20% compared with the market reformed oil liquid phase dechlorinating agent, while fully reducing the preparation cost, extending the service life, reducing the frequency of agent replacement, and saving a large amount of dechlorinating agent procurement costs for enterprises.

[0073] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dechlorinating agent, characterized in that: In terms of mass percentage, the dechlorinating agent comprises the following components: Calcium oxide 20-55%; Zinc oxide 10-30%; Alumina 15-40%; The balance is adhesive.

2. The dechlorinating agent according to claim 1, characterized in that In terms of mass percentage, the dechlorinating agent comprises the following components: Calcium oxide 25-50%; Zinc oxide 15-25%; Alumina 20-35%; The balance is adhesive.

3. The dechlorinating agent according to claim 1 or 2, characterized in that The specific surface area of ​​the alumina is 250-350m 2 / g; Preferably, the binder comprises any one of sesbania powder, kaolin, montmorillonite, sodium carboxymethyl cellulose or polysorbate, or a combination of at least two thereof.

4. A method for preparing a dechlorinating agent as claimed in any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: material preparation, mixing, co-grinding, strip extrusion, drying, activation and screening.

5. The preparation method according to claim 4, characterized in that: The material preparation includes preparing zinc oxide, specifically comprising: calcining zinc carbonate and chemically decomposing it to obtain zinc oxide; Preferably, the calcination process is carried out in a rotary kiln, and the temperature at the kiln head is 120-320°C and the temperature at the kiln tail is 250-480°C; Preferably, the loss on ignition during the calcination process is 2-10%.

6. The preparation method according to claim 4 or 5, characterized in that: The mixing includes: mixing calcium hydroxide, zinc oxide and aluminum oxide according to a set mass percentage and stirring evenly; Preferably, the mixing further comprises adding a binder.

7. The preparation method according to any one of claims 4 to 6, characterized in that: The mixing time is 20-40min; Preferably, the diameter of the extruded strip is 3-5 mm; Preferably, the drying temperature is 60-100° C. and the drying time is 6-10 h.

8. The preparation method according to any one of claims 4 to 7, characterized in that: The activation temperature is 300-380°C and the activation time is 2-4h; Preferably, the mesh size of the sieving is 4-40 meshes.

9. The preparation method according to any one of claims 4 to 8, characterized in that: The preparation method comprises the following steps: material preparation, mixing, mixing and grinding, extrusion, drying, activation and screening; The material preparation includes preparing zinc oxide, specifically including: calcining zinc carbonate in a rotary kiln, controlling the temperature at the kiln head to 120-320°C, the temperature at the kiln tail to 250-480°C, the ignition loss to 2-10%, and obtaining zinc oxide after chemical decomposition; the mixing includes: mixing calcium hydroxide, zinc oxide and aluminum oxide according to a set mass percentage, adding a binder and stirring evenly; the mixing and rolling time is 20-40 minutes; the diameter of the extruded strips is 3-5mm; the drying temperature is 60-100°C, the time is 6-10h; the activation temperature is 300-380°C, the time is 2-4h; the sieving mesh size is 4-40 meshes.

10. An application of the dechlorinating agent according to any one of claims 1 to 3, characterized in that: The dechlorinating agent is used to remove organic chlorine and hydrogen chloride in the reformed oil.

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