Heat balance aid as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of low-carbon dehydrogenation aids, and particularly relates to a heat balance aid as well as a preparation method and application thereof. The heat balance auxiliary agent comprises Al, Ca, Si, Cu and Mn elements existing in an oxide form; wherein the Al2O3, the CaO and the SiO2 jointly form a skeleton structure of the auxiliary agent, and the CuO and the MnO2 are used as active components and are attached to the skeleton structure; the molar ratio of metal elements in the heat balance auxiliary agent is as follows: Al: Ca: Si: Cu: Mn = (49-78.9): (15-25): (1-10): (5-15): (0.1-1). The heat balance additive prepared by the invention shows excellent anti-sintering capability, long service life and stable heat supply performance under harsh reaction conditions such as propane dehydrogenation, and can effectively improve the selectivity of target olefin and reduce the generation of byproducts such as methane.

Description

Technical Field

[0001] This invention belongs to the field of low-carbon dehydrogenation aid technology, specifically relating to a heat balance aid, its preparation method, and its application. Background Technology

[0002] Propylene is an important basic organic chemical raw material, and its downstream products include a series of chemicals closely related to human production and daily life, such as polypropylene, propylene oxide, acrylic acid, and acrylonitrile. Currently, industrial propylene production mainly comes from oil-based steam cracking, catalytic cracking processes, or coal-based methanol-to-olefins processes. Compared with traditional routes, propane catalytic dehydrogenation technology, which specifically produces propylene, has a simple process, and low investment costs, has become an important way to increase propylene production in industry.

[0003] Alkane dehydrogenation is typically an endothermic reaction, and the entire process can be operated as an adiabatic cyclic process. On one hand, in the Catofin propane dehydrogenation process, the heat of the catalyst bed mainly comes from hot air, resulting in different temperature ranges at different bed heights—higher at the top, lower in the middle, and even lower at the bottom—leading to lower catalyst reactivity. On the other hand, the inherently uneven pressure drop in the bed causes inconsistent temperature drops at different locations during the reaction due to flow deviation, resulting in uneven reaction and severely impacting catalyst lifespan and propylene yield. Therefore, supplementing the reaction system with heat during the reaction reduces the temperature difference and improves product selectivity. This has led to the development of dehydrogenation reaction promoters.

[0004] Chinese invention patent application CN108176405A discloses an alkane dehydrogenation reaction enhancing agent, which contains 15m%-18m% CaO, 70m%-80m% Al2O3, 6m%-15m% CuO, and 0.01m%-3m% oxides or mixtures thereof selected from Group VIII, Group VI, Group IA, Group IIA and rare earth elements; it has two active phases, CuO and CuO·CuSO4, on a composite support composed of CaAl4O7 spinel and Al2O3, with Al2O3 having the largest proportion. Al2O3 reacts with CuO to generate red aluminum copper spinel. Aluminum copper spinel is easily aged during hydrothermal reaction but is not easily reduced, thus resulting in poor hydrothermal performance.

[0005] Chinese invention patent application CN117925196A discloses a heat balance material for the dehydrogenation process of low-carbon alkanes, its preparation method, and its application. The heat balance material contains a carrier, a main active component, and a co-active component. The main active component includes Cu 3m%-10m% and Ca 10m%-15m%, and the co-active component includes Ca and at least one element Sn from Group IVA. However, co-impregnation of calcium and copper can lead to excessively high viscosity of the impregnation solution, affecting the impregnation effect.

[0006] Therefore, in order to improve the temperature distribution and heat reserve of the propane dehydrogenation reaction bed, it is necessary to develop a heat balance aid for the propane dehydrogenation process. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a heat balance agent, its preparation method, and its application.

[0008] To achieve the above-mentioned objectives of this invention, the specific technical solution adopted by this invention is as follows: A heat balancing agent comprising Al, Ca, Si, Cu and Mn elements in oxide form; wherein Al2O3, CaO and SiO2 together constitute the framework structure of the heat balancing agent, and CuO and MnO2 are attached to the framework structure as active components. The molar ratio of metal elements in the heat balance additive is: Al:Ca:Si:Cu:Mn=49-78.9:15-25:1-10:5-15:0.1-1.

[0009] Preferably, the composition of the heat balance additive, based on a total weight of 100wt%, includes: 60-80wt% Al2O3, 10-20wt% CaO, 1-10wt% SiO2, 4-12wt% CuO, and 0.1-1.5wt% MnO2.

[0010] Preferably, the properties of the heat balancing agent include: a cylindrical strip with a diameter of 3-5 mm and a length of 5-15 mm, and a lateral compressive strength ≥450 N / cm.

[0011] This invention also relates to a method for preparing the above-mentioned heat balance agent, comprising the following steps: (1) Mix aluminum-containing raw materials, calcium-containing raw materials, silicon-containing raw materials, binders and lubricants to obtain a mixture; (2) The mixture is extruded into strips, dried, and granulated to obtain strips; (3) The strip material is first roasted to obtain the carrier; (4) Prepare an impregnation solution containing copper and manganese sources, impregnate the carrier in the impregnation solution, and then dry and calcine it to obtain the heat balance additive.

[0012] Preferably, the aluminum-containing raw material in step (1) is selected from at least one of boehmite, boehmite and monohydrate; the calcium-containing raw material is selected from at least one of calcium hydroxide, calcium oxide, calcium carbonate, calcium nitrate and calcium acetate; the silicon-containing raw material is selected from at least one of silica sol, silica, diatomaceous earth and water glass; the binder is selected from at least one of nitric acid, citric acid, acetic acid and aluminum sol; and the lubricant is selected from at least one of guar gum powder, polyvinyl alcohol and polyethylene glycol.

[0013] Preferably, the weight ratio of the aluminum-containing raw material, calcium-containing raw material, silicon-containing raw material, binder and lubricant in step (1) is (50-75):(10-25):(1-10):(2-8):(1-5).

[0014] Preferably, the drying temperature in step (2) is 100-150℃ and the drying time is 2-4h; the working parameters of the first calcination in step (3) include: heating to 800-1000℃ at a heating rate of 1-5℃ / min in an air atmosphere, and holding at this temperature for 2-4h.

[0015] Preferably, the copper source in step (4) is copper nitrate, and the manganese source is at least one of manganese nitrate, manganese acetate, or potassium permanganate; in the impregnation solution, by mass fraction, copper nitrate:water:manganese source = (40-60):(40-60):(0.1-1.5).

[0016] Preferably, the drying parameters in step (4) include: drying at 100-150℃ for 2-4 hours; the second calcination parameters include: heating to 800-1200℃ at a heating rate of 2-10℃ / min in an air atmosphere, and calcining at this temperature for 2-4 hours.

[0017] This invention also relates to the application of the above-mentioned heat balance aid in the dehydrogenation of alkane to olefins reaction.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention introduces SiO2 into the thermal balance additive skeleton, which forms a more complex and stable high-temperature composite oxide phase with Al2O3 and CaO, significantly improving the thermal stability and mechanical strength of the skeleton, and effectively inhibiting the mutual diffusion and sintering of active components and carrier at high temperature.

[0019] (2) The active components (MnO2 and CuO) in this invention have a synergistic effect. MnO2 itself has good redox properties and thermal stability, and can produce a synergistic effect with CuO to jointly regulate the redox cycle, making the heat storage and heat release performance of the additive more stable and longer-lasting, and less prone to deactivation in a reducing atmosphere.

[0020] (3) The heat balance additive prepared in this invention exhibits excellent anti-sintering ability, long service life and stable heating performance under harsh reaction conditions such as propane dehydrogenation, which can effectively improve the selectivity of target olefins and reduce the generation of by-products such as methane. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are not intended to limit the present invention, but only to illustrate the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0022] Boehmite was purchased from Shandong Bairui Chemical Co., Ltd.; silica was purchased from Hubei Huifu Nanomaterials Co., Ltd., model: HL-150; guar gum was purchased from Hebei Xingxu Biotechnology Co., Ltd.; diatomite was purchased from Hebei Huishun Mining Co., Ltd., model: 325; silica sol was purchased from Yangzhou Zhongtianli New Material Co., Ltd., model: ZTL-JN.

[0023] Example 1 A heat balance additive, by mass percentage, has the following composition: Al2O3 71.5%, CaO 14.3%, SiO2 2.9%, CuO 10.7%, MnO2 0.6%.

[0024] The preparation method of the above-mentioned heat balance agent includes the following steps: (1) Add 714g of boehmite, 133g of calcium hydroxide, 21g of silica, 30g of nitric acid (65% concentration) (dissolved in 370g of water) and 20g of guar gum powder to a kneader to obtain a mixture.

[0025] (2) After mixing and kneading the mixture for 30 minutes, extrude it into strips on a 5mm perforated plate. After drying the strips at 120℃ for 3 hours, cut them into pellets to obtain strip material.

[0026] (3) The strip material was heated to 900℃ at 2.5℃ / min and calcined for 3 hours to obtain the carrier.

[0027] (4) Dissolve 52g of copper nitrate and 0.8g of manganese nitrate in 47g of deionized water. Impregnate 100g of the above carrier using the equal volume method. After impregnation, dry at 120℃ for 3h, and then calcine in air at 1200℃ for 3h at a rate of 5℃ / min to obtain the heat balance additive.

[0028] Example 2 A heat balance additive, by mass percentage, has the following composition: Al2O3 68.6%, CaO 17.1%, SiO2 5.7%, CuO 8.0%, MnO2 0.6%.

[0029] The preparation method of the above-mentioned heat balance agent includes the following steps: (1) Add 686g of boehmite, 122g of calcium oxide, 100g of silica sol, 30g of nitric acid (65% concentration) (dissolved in 370g of water) and 20g of guar gum powder to a kneader to obtain a mixture.

[0030] (2) After mixing and kneading the mixture for 30 minutes, extrude it into strips on a 5mm perforated plate. After drying the strips at 100℃ for 4 hours, cut them into pellets to obtain strips.

[0031] (3) The strip material was heated to 800℃ at 2℃ / min and calcined for 4 hours to obtain the carrier.

[0032] (4) Dissolve 48g of copper nitrate and 1.2g of manganese acetate in 51g of deionized water. Impregnate 100g of the above carrier using the equal volume method. After impregnation, dry at 100℃ for 4h, and then calcine in air at 3℃ / min to 1000℃ for 4h to obtain the heat balance additive.

[0033] Example 3 A heat balance additive, by mass percentage, has the following composition: 72.1% Al2O3, 15.0% CaO, 4.1% SiO2, 8.5% CuO, and 0.3% MnO2.

[0034] The preparation method of the above-mentioned heat balance agent includes the following steps: (1) Add 743g of boehmite, 196g of calcium carbonate, 35g of diatomaceous earth, 35g of nitric acid (65% concentration) (dissolved in 365g of water) and 18g of guar gum powder to a kneader to obtain a mixture.

[0035] (2) After mixing and kneading the mixture for 30 minutes, extrude it into strips on a 5mm perforated plate. After drying the strips at 150℃ for 2 hours, cut them into pellets to obtain strip material.

[0036] (3) The strip material was heated to 1000℃ at 3.5℃ / min and calcined for 2 hours to obtain the carrier.

[0037] (4) Dissolve 50g of copper nitrate and 1.0g of manganese nitrate in 49g of deionized water. Impregnate 100g of the above carrier using the equal volume method. After impregnation, dry at 150℃ for 2h, and then calcine in air at 8℃ / min to 1200℃ for 2h to obtain the heat balance additive.

[0038] Comparative Example 1 The only difference between this comparative example and Example 1 is that the active component used is only CuO, without MnO2.

[0039] The preparation method differs from Example 1 only in step (4), specifically: 52g of copper nitrate is dissolved in 47g of deionized water. 100g of the above carrier is impregnated using the equal volume method. After impregnation, it is dried at 120℃ for 3h, and then calcined in air at 1200℃ for 3h at a rate of 5℃ / min to obtain the heat balance additive.

[0040] Comparative Example 2 The only difference between this comparative example and Example 1 is that the active component used is only MnO2, without CuO.

[0041] The preparation method differs from Example 1 only in step (4), where CuO is replaced with an equimolar amount of manganese nitrate. Specifically, 147g of manganese nitrate is dissolved in 47g of deionized water. 100g of the above-mentioned carrier is impregnated using the equal-volume method. After impregnation, the carrier is dried at 120℃ for 3h, and then calcined in air at 1200℃ for 3h at a rate of 5℃ / min to obtain the heat balance additive.

[0042] Comparative Example 3 The only difference between this comparative example and Example 1 is the content of MnO2.

[0043] The preparation method differs from Example 1 only in step (4), specifically: 52g of copper nitrate and 1.5g of manganese nitrate are dissolved in 47g of deionized water. 100g of the above carrier is impregnated using the equal volume method. After impregnation, the carrier is dried at 120℃ for 3h, and then calcined in air at 1200℃ for 3h at a rate of 5℃ / min to obtain the heat balance additive.

[0044] Comparative Example 4 The only difference between this comparative example and Example 1 is that Fe2O3 is used instead of MnO2.

[0045] The preparation method differs from Example 1 only in step (4), specifically: 52g of copper nitrate and 1.1g of ferric nitrate are dissolved in 47g of deionized water. 100g of the above carrier is impregnated using the equal volume method. After impregnation, the carrier is dried at 120℃ for 3h, and then calcined in air at 1200℃ for 3h at a rate of 5℃ / min to obtain the heat balance additive.

[0046] Comparative Example 5 The only difference between this comparative example and Example 1 is that TiO2 is used instead of SiO2.

[0047] The only difference between the preparation method and Example 1 is that 21g of silica in step (1) is replaced with 15g of tetraethyl titanate.

[0048] Comparative Example 6 The only difference between this comparative example and Example 1 is that ZrO2 is used instead of SiO2.

[0049] The only difference between the preparation method and Example 1 is that 21g of silica in step (1) is replaced with 28g of zirconium oxychloride.

[0050] Comparative Example 7 The only difference between this comparative example and Example 1 is the SiO2 content.

[0051] The only difference between the preparation method and Example 1 is that the 21g of silica in step (1) is adjusted to 4g.

[0052] Comparative Example 8 The only difference between this comparative example and Example 1 is the SiO2 content.

[0053] The only difference between the preparation method and Example 1 is that the amount of silica in step (1) is adjusted from 21g to 80g.

[0054] Comparative Example 9 The only difference between this comparative example and Example 1 is that the calcination temperature in step (3) is raised to 1200°C.

[0055] Effect test Test Example 1: Physical Properties and Thermal Stability Test 1. Compressive strength: Using a universal testing machine (model: Instron 5967), with an indenter speed of 1 mm / min, the sample was placed horizontally between two parallel indenters (the contact length was 1 / 2 of the sample length). Ten complete cylindrical strips (without cracks or notches) were tested. The maximum pressure at fracture was recorded, and the lateral compressive strength was calculated (lateral compressive strength = maximum pressure / contact length). The maximum and minimum values ​​were removed, and the average value was taken.

[0056] 2. Thermal shock test: Place the sample in a muffle furnace at 600℃ for 30 min (heating rate 5℃ / min), then quickly and completely immerse it in 25℃ deionized water with tweezers. After soaking for 5 min, remove the sample and dry it at 120℃ for 2 h. Repeat the above operation 50 times. After each cycle, observe the sample with a stereomicroscope (magnification 20x). Cracks with a width ≥0.01 mm are considered valid cracks.

[0057] The test results are shown in Table 1.

[0058] Table 1 Performance Test Results

[0059] Test Example 2: Performance Test of Propane Dehydrogenation Reaction The process used was a fixed-bed reactor with a constant temperature. A chromium-based catalyst was selected as the main catalyst. Different heat balance additives were compared and evaluated. The heat balance additives were mixed with the dehydrogenation main catalyst at a mass ratio of 1:1. The reaction conditions were: temperature 600℃, pressure 0.05 MPa, and propane weight hourly space velocity 1 h⁻¹. -1 The evaluation results are shown in Table 2.

[0060] Table 2 Results of propane dehydrogenation reaction performance tests

[0061] Test Example 3: Long-term stability test To verify the long-term stability of the additive of this invention, a 500-hour continuous reaction experiment was conducted. Samples were taken and analyzed every 100 hours to record the retention of propylene selectivity. Strength decay rate = (initial lateral pressure strength - lateral pressure strength after 500 hours) / initial lateral pressure strength × 100%. The test results are shown in Table 3.

[0062] Table 3 Long-term stability test results

[0063] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A heat balance aid, characterized in that, The heat balance aid contains Al, Ca, Si, Cu and Mn elements in the form of oxides; wherein, Al2O3, CaO and SiO2 jointly constitute a skeleton structure of the heat balance aid, and CuO and MnO2 are attached to the skeleton structure as active components; The molar ratio of the metal elements in the heat balance aid is: Al:Ca:Si:Cu:Mn=49-78.9:15-25:1-10:5-15:0.1-1.

2. The heat balance aid according to claim 1, characterized in that The composition of the heat balance aid, based on the total weight of the heat balance aid, includes: Al2O3 60-80wt%, CaO 10-20wt%, SiO2 1-10wt%, CuO 4-12wt% and MnO2 0.1-1.5wt%.

3. The heat balance aid according to claim 1 or 2, characterized in that, The property parameters of the heat balance aid include: a cylindrical strip with a diameter of 3-5mm and a length of 5-15mm, and a side pressure strength ≥450 N / cm.

4. A process for the preparation of a heat balance aid as claimed in any one of claims 1 to 3, characterized in that, The method comprises the following steps: (1) mixing an aluminum-containing raw material, a calcium-containing raw material, a silicon-containing raw material, a binder and a lubricant to obtain a mixture; (2) extruding the mixture into a strip, drying, and cutting the strip to obtain a strip material; (3) first roasting the strip material to obtain a carrier; (4) preparing an impregnation solution containing a copper source and a manganese source, impregnating the carrier in the impregnation solution, and then drying and second roasting to obtain the heat balance aid.

5. The production method according to claim 4, characterized by, In step (1), the aluminum-containing raw material is selected from at least one of pseudo-boehmite, boehmite and diaspore; the calcium-containing raw material is selected from at least one of calcium hydroxide, calcium oxide, calcium carbonate, calcium nitrate and calcium acetate; the silicon-containing raw material is selected from at least one of silica sol, white carbon black, diatomite and water glass; the binder is selected from at least one of nitric acid, citric acid, acetic acid and aluminum sol; and the lubricant is selected from at least one of sesbania gum, polyvinyl alcohol and polyethylene glycol.

6. The preparation method according to claim 4, characterized in that, In step (1), the weight ratio of the aluminum-containing raw material, the calcium-containing raw material, the silicon-containing raw material, the binder and the lubricant is (50-75):(10-25):(1-10):(2-8):(1-5).

7. The preparation method according to claim 4, characterized in that, In step (2), the drying temperature is 100-150℃, and the drying time is 2-4h; and in step (3), the working parameters of the first roasting include: increasing the temperature to 800-1000℃ at a temperature increasing rate of 1-5℃ / min in an air atmosphere, and maintaining the temperature for 2-4h.

8. The preparation method according to claim 4, characterized in that, In step (4), the copper source is copper nitrate, and the manganese source is at least one of manganese nitrate, manganese acetate or potassium permanganate; and in the impregnation solution, the mass ratio of copper nitrate: water: manganese source is (40-60):(40-60):(0.1-1.5).

9. The preparation method according to claim 4, characterized in that, In step (4), the working parameters of the drying include: drying at 100-150℃ for 2-4h; and the working parameters of the second roasting include: increasing the temperature to 800-1200℃ at a temperature increasing rate of 2-10℃ / min in an air atmosphere, and roasting at this temperature for 2-4h.

10. Use of the heat balance aid according to any one of claims 1-3 in an alkanes dehydrogenation reaction to produce olefins.

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