A system for preparing a metal-modified alumina catalyst

Abstract

The utility model discloses a preparation system of metal modified alumina catalyst, including mixed water tank, the mixed water tank is connected with alkaline solution jar, modified metal salt solution jar and spray tank respectively through first filter, the bottom of modified metal salt solution jar is connected with reation kettle, the middle part of reation kettle still is provided with pH-temperature detection system, and the opening of adjusting valve is controlled through the pH value of detected, the bottom of spray tank is linked with the lateral wall of reation kettle, the bottom of reation kettle still is connected with drying device through filter press device, the filter press device still is connected with mixed water tank through second filter, circulating water pump in proper order, the lateral wall of spray tank still is connected with alumina bin through vacuum feeding machine. Through the accurate control of pH, the consumption of lye is reduced, and the system also has the advantages of low water consumption and dust pollution prevention.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to a preparation system for a metal-modified alumina catalyst. Background Technology

[0002] Metal-modified alumina catalysts can be widely used in chemical reaction processes such as dehydration, esterification, amination, and aldol condensation. In reactions involving the dehydration of higher alcohols to α-olefins or the dehydration of diols to enols, which produce high-value-added fine chemicals, the catalyst's acidity / basicity, specific surface area, and physical dimensions directly affect its conversion rate and selectivity. Methods for modifying metal-modified alumina catalysts include impregnation, kneading, and precipitation loading. Precipitation loading often involves the use of precipitation reactor systems. Reactions in these reactors involve the mixing and reaction of solid, liquid, and even gas phases. While precipitation reactions operate at low temperatures and pressures, current reactor systems have shortcomings in areas such as precise pH monitoring, recycling of alkaline reaction residues, solid dust pollution, and alkaline odor emissions. In actual experiments or production, this not only results in high water and alkali consumption but also poses potential risks related to safety, environmental protection, and occupational health. Utility Model Content

[0003] To address the shortcomings of existing technologies, this invention provides a preparation system for metal-modified alumina catalysts. This system reduces the consumption of alkaline solution through precise pH control, while also offering advantages such as low water consumption and avoidance of dust pollution.

[0004] A system for preparing a metal-modified alumina catalyst includes a mixing tank, which is connected to an alkaline solution tank, a modified metal salt solution tank, and a spray tank via a first filter. The bottom of the modified metal salt solution tank is connected to a reaction vessel. A liquid distributor and a gas distributor are respectively installed at the top and bottom of the reaction vessel. The liquid distributor is connected to the bottom of the alkaline solution tank via a regulating valve. A gas inlet is also provided on the side wall of the reaction vessel and connected to the gas distributor. A pH-temperature detection system is also installed in the middle of the reaction vessel to control the opening of the regulating valve based on the detected pH value. The bottom of the spray tank is connected to the side wall of the reaction vessel, and the bottom of the reaction vessel is connected to a drying device via a filter press. The filter press is connected to the mixing tank via a second filter and a circulating water pump. An alumina silo is also connected to the side wall of the spray tank via a vacuum feeder.

[0005] Preferably, the pH-temperature detection system includes a plurality of pH-temperature detectors that are evenly distributed.

[0006] Preferably, the pH-temperature detection system includes three evenly distributed pH-temperature detectors.

[0007] Preferably, a sprayer is provided at the feed inlet of the spray tank.

[0008] Preferably, a constant pressure valve is provided at the top of the side wall of the reactor and at the top of the spray tank.

[0009] Preferably, the reactor is also equipped with a stirrer.

[0010] Preferably, both the liquid distributor and the gas distributor are multi-tube distributors.

[0011] Preferably, the filter press is a plate and frame filter press.

[0012] Preferably, the drying device is a flash dryer.

[0013] Advantages of this utility model: (1) This utility model can recycle the filtrate formed after the reaction by connecting the filter press, filter, circulating water pump, mixing tank and spray tank, thereby reducing the water consumption per ton of catalyst production, which is beneficial to water conservation and cost reduction. (2) This utility model can realize the conveying of powdered alumina carrier in a sealed environment by connecting the alumina silo, vacuum feeder and spray tank, effectively preventing or avoiding dust overflow and flying, reducing dust pollution to the production site and harm to people. (3) This utility model improves the single-pass effective utilization rate and comprehensive effective utilization rate of metals through precise detection and control of pH, reduces the residual amount of metal ions in the filtrate, and the pH of the filtrate formed after the reaction is between 7 and 8, which is not much different from the pH of fresh water. It can be recycled, reducing the consumption of alkaline solution when producing one ton of catalyst, which is beneficial to reducing the corrosion caused by alkaline solution contacting metal and the harm to human body. Attached Figure Description

[0014] Figure 1 A schematic diagram of the structure of this utility model; Among them, 2-alkaline solution tank; 3-regulating valve; 5-modified metal salt solution tank; 7-sprayer; 8-spray tank; 9-vacuum feeder; 10-alumina silo; 11-reaction vessel; 13-liquid distributor; 14-gas distributor; 20-pressure filter; 21-drying device; 23-second filter; 24-circulating water pump; 25-mixing water tank; 27-first filter. Detailed Implementation

[0015] Example 1 A system for preparing a metal-modified alumina catalyst includes a mixing tank 25, which is connected to an alkaline solution tank 2, a modified metal salt solution tank 5, and a spray tank 8 via a first filter 27. The bottom of the modified metal salt solution tank 5 is connected to a reaction vessel 11. A liquid distributor 13 and a gas distributor 14 are respectively installed at the top and bottom of the reaction vessel 11. The liquid distributor 13 is connected to the bottom of the alkaline solution tank 2 via a regulating valve 3. A gas inlet is also provided on the side wall of the reaction vessel 11. The gas inlet is connected to the gas distributor 14; a pH-temperature detection system is also provided in the middle of the reactor 11, which controls the opening of the regulating valve 3 by detecting the pH value; the bottom of the spray tank 8 is connected to the side wall of the reactor 11, and the bottom of the reactor 11 is also connected to the drying device 21 through the filter press 20. The filter press 20 is also connected to the mixing tank 25 in sequence through the second filter 23 and the circulating water pump 24; the side wall of the spray tank 8 is also connected to the alumina silo 10 through the vacuum feeder 9.

[0016] The principle of this invention will be further explained using a metal-modified alumina catalyst for the dehydration of higher alcohols to α-olefins as an example, as detailed below: The modified metal solution (a mixed solution of lanthanum nitrate, nickel sulfate, and ferrous sulfate, with a total metal concentration of 0.5-2 mol / L and a molar ratio of lanthanum, nickel, and iron of 6:2:2) in the modified metal salt solution tank 5 is injected into the reaction vessel 11. The vacuum feeder 9 is started to transport the powdered alumina carrier from the alumina silo 10 into the spray tank 8. Simultaneously, water from the mixing water tank 25 is injected into the spray tank 8 to form a suspension of alumina and water. This suspension is then injected into the reaction vessel 11, and the reaction vessel 11 is heated to 30°C. At 50°C, air is introduced into the gas distributor 14 at the bottom of the reactor 11 through the gas inlet. At the same time, sodium carbonate or ammonia solution (0.5-1.2 mol / L) from the alkaline solution tank 2 is injected into the reactor 11 through the liquid distributor 13 at the top of the reactor 11. The opening of the regulating valve 3 is controlled by the pH value detected by the pH-temperature detection system, thereby adjusting the amount of alkaline solution added to maintain the pH value of the reactants in the reactor 11 between 5.5 and 8, and the reaction time is 2-4 hours. After the reaction is completed, the reactants are transferred to the filter press 20 to obtain filtrate and filter cake respectively. The filter cake is dried in the drying device 21 to obtain the catalyst. After filtration, the filtrate is pumped into the mixing tank 25 by the circulating water pump 24 to mix with the water in the mixing tank 25, thereby realizing the recycling of the filtrate. The recycling of the filtrate reduces the water consumption per ton of catalyst production, which is beneficial for water conservation and cost reduction. The pH of the filtrate is between 7 and 8, which can reduce the consumption of alkaline solution during the production of per ton of catalyst, which is beneficial for reducing corrosion caused by alkaline solution contacting metal and harm caused by contact with human body.

[0017] Example 2 Based on Embodiment 1 above, the pH-temperature detection system includes several uniformly distributed pH-temperature detectors. More preferably, the pH-temperature detection system includes three uniformly distributed pH-temperature detectors. The opening degree of the regulating valve 3 is controlled based on the average value of the detected pH. Several uniformly distributed pH-temperature detectors can more accurately reflect the pH value of the material.

[0018] A sprayer 7 is installed at the inlet of the spray tank 8. After water passes through the sprayer 7, it can moisten the airborne and floating powdered alumina carrier, preventing dust spillage and pollution.

[0019] The top of the side wall of the reactor 11 and the top of the spray tank 8 are both equipped with constant pressure valves to ensure that the pressure inside the reactor 11 and the spray tank 8 is constant.

[0020] The reactor 11 is also equipped with a stirrer with a rotation speed of 200-300 r / min to ensure uniform mixing of the reaction materials.

[0021] Both the liquid distributor 13 and the gas distributor 14 are multi-tube distributors.

[0022] The filter press 20 is a plate and frame filter press.

[0023] The drying device 21 is a flash dryer, which can dry and package the catalyst in a sealed environment, thus avoiding dust pollution of the production site and harm to human health.

Claims

1. A preparation system for a metal-modified alumina catalyst, comprising a mixing tank (25), characterized in that: The mixing tank (25) is connected to an alkaline solution tank (2), a modified metal salt solution tank (5), and a spray tank (8) via a first filter (27). The bottom of the modified metal salt solution tank (5) is connected to a reaction vessel (11). A liquid distributor (13) and a gas distributor (14) are respectively installed at the top and bottom of the reaction vessel (11). The liquid distributor (13) is connected to the bottom of the alkaline solution tank (2) via a regulating valve (3). A gas inlet is also provided on the side wall of the reaction vessel (11). The gas inlet is connected to the gas distributor (14). The reactor (11) is connected to the side wall of the reactor (11). The middle part of the reactor (11) is also equipped with a pH-temperature detection system, which controls the opening of the regulating valve (3) by detecting the pH value. The bottom of the spray tank (8) is connected to the side wall of the reactor (11). The bottom of the reactor (11) is also connected to the drying device (21) through the filter press (20). The filter press (20) is also connected to the mixing tank (25) in sequence through the second filter (23) and the circulating water pump (24). The side wall of the spray tank (8) is also connected to the alumina silo (10) through the vacuum feeder (9).

2. The preparation system for a metal-modified alumina catalyst according to claim 1, characterized in that: The pH-temperature detection system includes several pH-temperature detectors that are evenly distributed.

3. The preparation system for a metal-modified alumina catalyst according to claim 2, characterized in that: The pH-temperature detection system includes three evenly distributed pH-temperature detectors.

4. The preparation system for a metal-modified alumina catalyst according to claim 1, characterized in that: A sprayer (7) is provided at the inlet of the spray tank (8).

5. The preparation system for a metal-modified alumina catalyst according to claim 1, characterized in that: A constant pressure valve is provided at the top of the side wall of the reactor (11) and at the top of the spray tank (8).

6. The preparation system for a metal-modified alumina catalyst according to claim 1, characterized in that: The reactor (11) is also equipped with a stirrer.

7. The preparation system for a metal-modified alumina catalyst according to claim 1, characterized in that: Both the liquid distributor (13) and the gas distributor (14) are multi-tube distributors.

8. The preparation system for a metal-modified alumina catalyst according to claim 1, characterized in that: The filter press device (20) is a plate and frame filter press.

9. The preparation system for a metal-modified alumina catalyst according to claim 1, characterized in that: The drying device (21) is a flash dryer.

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