Continuous neutralization and aging reactor and use thereof

Abstract

The application discloses a continuous neutralization and aging reactor and application, mainly comprising a feeding system, a reactor main body and a discharging system, wherein the reactor main body adopts a sleeve type structure and comprises a reaction tube, an intermediate reactor and an ager from inside to outside. The application can realize continuous production of neutralization and aging reaction, and the materials are mixed and aged in a countercurrent mode, which is beneficial to the growth of catalyst active precursor crystal nucleus. The application can realize continuous production of neutralization and aging reaction, and the materials are mixed and aged in a countercurrent mode, which is beneficial to the growth of catalyst active precursor crystal nucleus. The high-temperature shift catalyst prepared by using the application has the advantages of high activity, low bulk specific gravity, strong stability and long service life.

Description

Technical Field

[0001] This invention relates to a continuous neutralization and aging reactor and its application, particularly suitable for the field of catalyst manufacturing. The continuous neutralization and aging reactor results in short reaction times, thorough material mixing, and uniform temperature and heat of the mixture, which is conducive to the growth of active precursor crystal nuclei for catalysts and can be continuously output to downstream washing processes. Background Technology

[0002] The neutralization and aging process is the core operational unit in catalyst preparation. The mixing and reaction process of nitrates, additives, and precipitants, as well as the aging stage, directly affect the activity of the final catalyst. Therefore, the time, temperature, and pH of the neutralization and aging processes must be strictly controlled. Using traditional stirred tank reactors results in insufficient material mixing, which is detrimental to the growth of catalyst precursor nuclei, leading to problems such as low catalyst activity, poor stability, and short lifespan. In addition, the production process uses a single-feed and single-discharge method after the reaction, resulting in low production efficiency and hindering large-scale production operations. Summary of the Invention

[0003] The purpose of this invention is to provide a continuous neutralization aging reactor and its application.

[0004] The main features of this invention are short reaction time, thorough mixing of materials, and uniform temperature and heat of the mixture, which is conducive to the growth of active precursor crystal nuclei of the catalyst and can be continuously output to the downstream washing process.

[0005] The main technical solution of the present invention is a continuous neutralization and aging reactor, characterized by comprising a reactor body, a feeding system, and a discharging system; the reactor body is a sleeve-type structure, comprising, from the inside out, a reaction tube, an intermediate reactor, and an aging device, wherein the reactor and the aging device are equipped with heating coils, overflow holes are provided in the lower middle part of the reaction tube and the top of the intermediate reactor, and baffles are provided outside the reaction tube and inside the intermediate reactor; the feeding system includes a feeding pipe extending into the reaction tube; the discharging system includes a discharging pipe extending into the aging device.

[0006] Generally, the feed line is equipped with a mass flow meter, a shut-off valve is provided at the rear end of the mass flow meter, and multiple rows of feed holes are provided on the feed pipe wall, with a diameter of 2-3 mm.

[0007] The diameter of the overflow hole in the lower part of the reaction tube is smaller than the diameter of the overflow hole at the top of the intermediate reactor.

[0008] The diameter of the overflow hole in the lower part of the reaction tube is 3-5 mm, and the diameter of the overflow hole at the top of the intermediate reactor is 5-8 mm.

[0009] A vertical baffle is provided around the overflow hole of the reaction tube.

[0010] The intermediate reactor is equipped with equidistant, staggered baffles.

[0011] The discharge pipe is located at the bottom of the aging unit, and the discharge pipe is connected to the return pipe through the liquid transfer pump and extends into the top of the aging unit.

[0012] The reflux pipe is equipped with a reflux valve, a production pipe, and a production valve.

[0013] The present invention also provides an application of a continuous neutralization aging reactor: the raw material enters the reaction tube equipped with a heating coil from the feed pipe, and undergoes preliminary mixing and reaction in the reaction tube. After the material overflows from the overflow hole of the reaction tube, it enters the intermediate reactor. The reacted material overflows from the top overflow hole to the aging unit equipped with a heating coil. Part of the aged material is sent to the downstream washing unit through the discharge pipe, and the rest circulates in the aging unit.

[0014] The raw materials used in this invention can be nitrates of different concentrations, such as copper nitrate, zinc nitrate, chromium nitrate, and aluminum nitrate.

[0015] The precipitant used in this invention can be any one or a mixture of several of Na2CO3, NaHCO3, NaOH, KHCO3, K2CO3 and ammonia.

[0016] The reactor body of the present invention is provided with a reaction tube in the inner layer, and multiple rows of overflow holes are left at the bottom of the reaction tube to control the material residence time to 3-5 seconds. A heating coil is installed on the outside of the reaction tube to control the neutralization temperature to 65-80℃.

[0017] The reactor body of the present invention has an intermediate reactor in the middle layer, and the top of the intermediate reactor has multiple rows of overflow holes to control the material residence time to 5-10 seconds.

[0018] The reactor body of the present invention is provided with an aging device on the outer layer, and a heating coil is installed on the outside of the aging device to control the temperature at 70-85℃.

[0019] The catalyst precursor prepared using the continuous neutralization and aging reactor of this invention, after washing, calcination, and pelletizing, yields a methanol synthesis catalyst with an activity of 1.15 g / ml·h and a bulk density of less than 1.25 g / cm³ after heat resistance. 3 .

[0020] This invention enables continuous production of neutralization and aging reactions, with countercurrent mixing and aging of materials, which is beneficial for the growth of catalyst active precursor crystal nuclei. The high-temperature shift catalyst prepared using the reactor of this invention has advantages such as high activity, low bulk density, strong stability, and long lifespan. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the continuous neutralization and aging reactor in the embodiment.

[0022] In the diagram: 1. Acid feed valve; 2. Alkali feed valve; 3. Acid mass flow meter; 4. Alkali mass flow meter; 5. Acid feed pipe; 6. Alkali feed pipe; 7. Heating coil; 8. Overflow hole; 9. Reaction pipe; 10. Intermediate reactor; 11. Overflow hole; 12. Baffle; 13. Aging unit; 14. Heating coil; 15. Discharge pipe; 16. Feed pump; 17. Outlet pipe; 18. Outlet valve; 19. Return pipe; 20. Return valve. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the embodiments and accompanying drawings.

[0024] The following examples are only for further explaining the content of the present invention and illustrating its effects; the effects of the method of the present invention are not limited thereto.

[0025] The structure of the continuous neutralization aging reactor in the following embodiments is referenced in the appendix. Figure 1 The reactor mainly consists of a reactor body, a feeding system, and a discharging system. The reactor body adopts a sleeve structure, which includes a reaction tube (9), an intermediate reactor (10), and an aging unit (13) from the inside out. Raw materials such as copper nitrate, zinc nitrate, nitrate, and precipitant enter the reaction tube (9) equipped with a heating coil (7) from the acid feed pipe (5) and the alkali feed pipe (6). The reaction tube (9) is equipped with an overflow hole (8), and the raw materials are initially mixed and reacted in the reaction tube (9). After overflowing from the overflow hole (8), the material enters the intermediate reactor (10). The intermediate reactor (10) is equipped with a baffle (12) to ensure that the material is fully mixed and that the reactant material has sufficient residence time. After the material in the intermediate reactor (10) reacts for a certain period of time, it reaches the top overflow hole (11). The reacted material overflows to the aging unit (13) equipped with a heating coil (14). Part of the aged material is sent to the downstream washing unit by the liquid transfer pump (16), and the rest circulates in the aging unit (13) to enhance the mixing effect.

[0026] In this embodiment, the feed pipeline is equipped with an acid feed valve (1), an alkali feed valve (2), an acid mass flow meter (3), and an alkali mass flow meter (4). Multiple rows of feed holes with a diameter of 2-3 mm are provided on the feed pipe wall. The diameter of the overflow hole (8) in the lower part of the reaction tube is 3-5 mm, and the diameter of the overflow hole (11) at the top of the intermediate reactor is 5-8 mm. Vertical baffles (12) are provided around the overflow hole outside the reaction tube, and equidistant staggered baffles (12) are provided inside the intermediate reactor. The discharge pipe (15) is located at the bottom of the aging tank. The discharge pipe is connected to the return pipe (19) via a feed pump and extends into the top of the aging tank. The return pipe is equipped with a return valve (20), a collection pipe (17), and a collection valve (18).

[0027] Example 1

[0028] Sodium carbonate was used as precipitant B, and a certain volume of copper solution (40 g / L) and zinc solution (35 g / L) were mixed to form mixture A. The feed was carried out in a parallel flow manner, and the temperature of the reaction tube was controlled at 70-75℃ (actually 71±1℃). The residence time of the material in the reaction tube was 4±0.5 seconds. After overflowing from the overflow hole of the reaction tube, the material flowed to the intermediate reactor for further mixing and reaction. The actual temperature in the intermediate reactor was controlled at 71±1℃, and the residence time was 8±0.5 seconds. The neutralized material entered the aging tank, where the residence time was 10-20 seconds (actually 15±1 seconds). The temperature inside the aging tank was controlled at 72-75℃ (actually 74±1℃). The aged material was then pumped downstream for washing, preparation of ternary slurry, drying, granulation, calcination, and tableting to obtain the finished catalyst CAT-1.

[0029] Example 2

[0030] Sodium bicarbonate was used as precipitant C, and a certain volume of copper solution (40 g / L) and zinc solution (35 g / L) were mixed to form mixture A. The mixture was fed in a parallel flow manner, with the reaction tube temperature controlled at 70-75℃ (actually 71±1℃). The residence time of the material in the reaction tube was 4±0.5 seconds. After overflowing from the reaction tube, the material flowed to the intermediate reactor for further mixing and reaction. The actual temperature in the intermediate reactor was controlled at 71±1℃, and the residence time was 8±0.5 seconds. The neutralized material entered the aging tank, where the residence time was 10-20 seconds (actually 15±1 seconds). The temperature inside the aging tank was controlled at 72-75℃ (actually 74±1℃). The aged material was then pumped downstream for washing, preparation of ternary slurry, drying, granulation, calcination, and tableting, with the process conditions identical to Example 1, yielding the catalyst product CAT-2.

[0031] Example 3

[0032] Sodium hydroxide was used as precipitant D, and a certain volume of copper solution (40 g / L) and zinc solution (35 g / L) were mixed to form mixture A. The mixture was fed in a parallel flow manner, with the reaction tube temperature controlled at 70-75℃ (actually 71±1℃). The residence time of the material in the reaction tube was 4±0.5 seconds. After overflowing from the reaction tube, the material flowed to the intermediate reactor for further mixing and reaction. The actual temperature in the intermediate reactor was controlled at 71±1℃, and the residence time was 8±0.5 seconds. The neutralized material entered the aging tank, where the residence time was 10-20 seconds (actually 15±1 seconds). The temperature inside the aging tank was controlled at 72-75℃ (actually 74±1℃). The aged material was then pumped downstream for washing, preparation of ternary slurry, drying, granulation, calcination, and tableting, with the process conditions the same as in Example 1, yielding the catalyst product CAT-3.

[0033] Example 4

[0034] Ammonia water was used as precipitant E, and a certain volume of copper solution (40 g / L) and zinc solution (35 g / L) were mixed to form mixture A. The mixture was fed in a parallel flow manner, with the reaction tube temperature controlled at 70-75℃ (actually 71±1℃). The residence time of the material in the reaction tube was 4±0.5 seconds. After overflowing from the reaction tube, the material flowed to the intermediate reactor for further mixing and reaction. The actual temperature in the intermediate reactor was controlled at 71±1℃, and the residence time was 8±0.5 seconds. The neutralized material entered the aging tank, where the residence time was 10-20 seconds (actually 15±1 seconds). The temperature inside the aging tank was controlled at 72-75℃ (actually 74±1℃). The aged material was then pumped downstream for washing, preparation of ternary slurry, drying, granulation, calcination, and tableting, with the process conditions the same as in Example 1, to obtain the catalyst product CAT-4.

[0035] Comparison sample

[0036] Sodium carbonate was used as precipitant B, and a certain volume of copper solution (40 g / L) and zinc solution (35 g / L) were mixed to form mixture A. The mixture was fed in a parallel flow manner and neutralized in a conventional stirred reactor. The temperature during the neutralization process was controlled at 70-75℃, but the actual temperature was 71±1℃. After neutralization, the temperature was raised to 74±1℃ for aging. The resulting material was then sent to downstream processes such as washing, preparing ternary slurry, drying, granulation, calcination, and tableting. The process conditions were the same as in Example 1, and the catalyst product CAT-Sample was obtained.

[0037] Sample testing

[0038] Catalyst samples: particle size 0.425~1.180 mm.

[0039] Activity testing: A micro fixed-bed continuous flow reactor was used. The catalyst loading was 2 ml, with a particle size of 16-40 mesh. Catalyst reduction was performed in a low-hydrogen atmosphere (H2:N2 = 5:95) with a programmed temperature increase (20℃ / h) for 10 hours. At a temperature of 230℃, the reducing gas was switched to the feed gas for activity testing. The activity testing conditions were a reaction pressure of 8.0 MPa and a space velocity of 10000 h⁻¹. -1 The temperature was 230℃, and the composition of the synthesis gas was H2:CO:CO2:N2 = 65:14:4:17 (v / v). After heat treatment at 350℃ for 20 h, the catalyst's activity was measured under the above conditions. The activity value was expressed as the space-time yield (g / ml) of methanol production. -1 h -1 The ratio of activity after heat resistance to initial activity is used to compare the thermal stability of the samples.

[0040] The activity test results are shown in Table 1. Among them, catalyst samples CAT-1, CAT-2, CAT-3 and CAT-4 were prepared in this invention.

[0041] Table 1. Activity test results

[0042]

[0043] The bulk density of the above catalysts was measured, and the results are shown in Table 2.

[0044] Table 2. Results of bulk density measurement

[0045] catalyst CAT-1 CAT-2 CAT-3 CAT-4 CAT-Sample Bulk density (g / ml) 1.23 1.21 1.24 1.23 1.40

[0046] As shown in Table 1, the methanol synthesis catalyst prepared by the present invention has a significantly better methanol yield than the comparative sample prepared by the traditional method, and also has higher heat resistance and better stability. As shown in Table 2, the methanol synthesis catalyst prepared by the present invention has a lower bulk density, indicating that the present invention has obvious advantages over the existing methods and can better meet market demands.

Claims

1. A method for preparing a methanol synthesis catalyst using a continuous neutralization and aging reactor, characterized in that, The continuous neutralization and aging reactor includes a reactor body, a feeding system, and a discharging system. The reactor body is a sleeve-type structure, consisting of a reaction tube, an intermediate reactor, and an aging unit from the inside out. The reaction tube and the aging unit are equipped with heating coils. Overflow holes are provided in the lower middle part of the reaction tube and the top of the intermediate reactor. The diameter of the overflow hole in the lower middle part of the reaction tube is 3-5 mm, and the diameter of the overflow hole at the top of the intermediate reactor is 5-8 mm. Vertical baffles are provided around the overflow holes outside the reaction tube, and staggered baffles are provided inside the intermediate reactor. The feeding system includes a feed pipe extending into the reaction tube. A mass flow meter is provided on the feed pipe, and a shut-off valve is provided at the rear end of the mass flow meter. Multiple rows of feed holes with a diameter of 2-3 mm are provided on the wall of the feed pipe. The discharging system includes a discharge pipe extending into the aging unit. The discharge pipe is located at the bottom of the aging unit and is connected to a return pipe via a liquid transfer pump, extending into the top of the aging unit. The method includes the following steps: the raw material for preparing the methanol synthesis catalyst precursor enters the reaction tube equipped with a heating coil through the feed pipe, and undergoes preliminary mixing and reaction in the reaction tube. After overflowing from the overflow hole of the reaction tube, the material enters the intermediate reactor. The reacted material overflows from the top overflow hole to the aging tank equipped with a heating coil. Part of the aged material is sent to the downstream washing unit through the discharge pipe, and the rest circulates in the aging tank. The prepared catalyst precursor is washed, calcined, and formed into tablets to obtain the methanol synthesis catalyst.

2. The method as described in claim 1, characterized in that, The reflux pipe is equipped with a reflux valve, a production pipe, and a production valve.

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