Multi-stage mixing type homogenizing device for acrylic acid production

Abstract

The utility model belongs to the technical field of acrylic acid production, and particularly relates to a multi-stage mixing type homogenizing device for acrylic acid production. The multi-stage mixing type acrylic acid production homogenizing device comprises a first oxidation reactor, the first oxidation reactor is connected with a pipeline mixer A, the pipeline mixer A is connected with a premixer, the premixer is connected with an air preheater, the pipeline mixer A is provided with a pipeline connected with a propylene superheater, and the pipeline is connected with a propylene superheater. The first oxidation reactor is connected with a feed port of a pipeline mixer B, and the pipeline mixer B is connected with the second oxidation reactor. According to the utility model, the multi-stage mixing design of the pipeline mixer, the premixer and the air preheater is adopted, and the combination of a feeding structure and internal mixing elements is optimized, so that various materials such as propylene, air, steam, circulating gas and the like can be effectively ensured to be fully mixed before entering the reactor; the problem of insufficient local reaction or side reaction increase caused by non-uniform mixing is avoided, so that the reaction rate and the selectivity are improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of acrylic acid production, and in particular relates to a multi-stage mixing type acrylic acid production homogenizing device. Background Art

[0002] The raw materials for producing acrylic acid by the propylene oxidation method are propylene and humidified air. Propylene, air and water vapor pass through the catalyst bed in a certain ratio and undergo a gas-phase heterogeneous oxidation reaction at a certain temperature. Propylene is oxidized to acrolein in the first reactor, and acrolein is further oxidized to acrylic acid in the second reactor. Propylene, air and water vapor all need to enter the reactor for reaction. If they enter the reactor directly, the following situations may occur: uneven gas mixing, insufficient reaction, thereby reducing the production efficiency of the system; insufficient reaction of the mixed gas will increase the consumption of raw materials, thereby increasing production costs; uneven gas mixing will increase the occurrence of side reactions, resulting in reduced product quality.

[0003] CN214991236U discloses a complete set of equipment for preparing acrylic acid by circulating propylene oxidation method, which is provided with a plurality of mixers, which mainly include a steam mixer, a main reactor feed mixer and a secondary reactor feed mixer. The steam mixer is provided with three feed ports, which are respectively connected to a medium-pressure steam line, a feed air compressor and a circulating air compressor for mixing steam and air. The main reactor feed mixer has a plurality of feed lines, which are respectively connected to a propylene superheater and a steam mixer. Its discharge line is connected to a main reaction system for mixing propylene and reaction gas. The discharge line of the secondary reactor feed mixer is connected to the secondary reaction system for mixing gas entering the secondary reaction system. The setting of the mixer ensures that it has a good mixing effect. However, the mixer is only introduced, and the feeding time of materials at different temperatures and the internal structure of the mixer are not reasonably regulated, resulting in an unstable mixing effect and being unable to adapt to the reaction requirements under different working conditions, thereby affecting production efficiency and product quality.

[0004] Therefore, it is necessary to rationally design the feeding time of different materials and the internal structure of the mixer to improve the uniformity and efficiency of the reaction. Utility Model Content

[0005] The purpose of the utility model is to overcome the defects of the prior art and provide a multi-stage mixing type acrylic acid production homogenization device, which adopts a multi-stage mixing design of a pipeline mixer, a premixer and an air preheater, optimizes the combination of the feed structure and the internal mixing elements, and can effectively ensure that various materials such as propylene, air, steam and circulating gas are fully mixed before entering the reactor, avoiding insufficient local reaction or increased side reactions due to uneven mixing.

[0006] The utility model discloses a multi-stage hybrid acrylic acid production homogenizing device, comprising an air pipeline and a first oxidation reactor, wherein the air pipeline is connected to an air filter, the air filter is connected to a turbine compressor, the turbine compressor is connected to an air preheater, the air preheater is connected to a premixer, the premixer is connected to a pipeline mixer A, the pipeline mixer A is connected to the first oxidation reactor, a discharge port is arranged at the bottom of the first oxidation reactor and is connected to a feed port of a pipeline mixer B, the pipeline mixer B is connected to a second oxidation reactor, and a discharge port is arranged at the bottom of the second oxidation reactor for conveying reacted materials to the next process.

[0007] Preferably, the air preheater is provided with a pipeline connected to the pipeline mixer B, and the feed port of the premixer is connected to the steam pipeline.

[0008] Preferably, the feed port of the pipeline mixer A is connected to the circulating gas pipeline, the pipeline mixer A is provided with a pipeline connected to the propylene superheater, and the propylene superheater is connected to the propylene spherical tank through the pipeline.

[0009] Preferably, the pipeline mixer A is composed of an external shell and an internal mixing element, and three feed ports are arranged on one side of the feed port of the external shell, feed port A is located on the side wall, feed port B and feed port C are located on the upper and lower sides, feed port A is used to convey a mixture of steam and air, feed port B is used to convey propylene, and feed port C is used to convey circulating gas. The external shell is trumpet-shaped as a whole, and one side of the feed port is narrower than one side of the discharge port; further, the width of one side of the discharge port of the pipeline mixer A is 1.5 times the width of the narrowest part of the feed port side.

[0010] Preferably, the feed port A and feed port B both extend into the interior of the pipeline mixer A for a certain distance, and the gas outlets of the feed port A and feed port B are spray gun structures. Furthermore, the spray gun structure has a pipe opening width at one end of the air inlet that is greater than that at the air outlet end.

[0011] Preferably, the internal mixing elements are of two types, spiral blades and porous plates. The inlet and outlet of the pipeline mixer A are porous plate structures, and the remaining positions are spiral blade structures. The front and rear of the spiral blades are respectively connected with porous plates.

[0012] Preferably, the pipeline mixer A and the pipeline mixer B have the same structure, and the pipeline mixer B is provided with two feed ports, which are respectively located on the side wall and the upper wall. Furthermore, the feed port on the side wall of the pipeline mixer B is used to transport the product after the reaction of the first oxidation reactor, and the feed port on the upper wall is used to transport air preheated by the air preheater. The structure of the two feed ports is the same as that of the feed port A and the feed port B on the pipeline mixer A.

[0013] Specifically, the working process of the multi-stage mixed acrylic acid production homogenization device of the utility model is as follows: fresh air is dust-removed by an air filter and then transported to a turbine compressor through a pipeline. The compressed air enters an air preheater, which heats the air to a required temperature and then is divided into two paths; one path of air enters a premixer and is mixed with steam transported by a steam pipeline, and after mixing, enters a next mixing section through a feed port A on the side wall of a pipeline mixer A. A feed port B and a feed port C are also provided on one side of the feed port of the pipeline mixer A, which are respectively located on the upper and lower walls of one side of the feed port. The feed port B is used to transport propylene from a propylene superheater, and the feed port C is used to transport circulating gas from a reaction system for recycling, so as to realize gas circulation; both the feed port A and the feed port B are spray gun structures, so as to ensure that the two reaction gases can quickly realize heat transfer, and the three raw materials are fully mixed through a mixing element (passing through a porous plate, a spiral blade, and a porous plate in sequence) arranged inside the pipeline mixer A, and enter the top of the first oxidation reactor, where they react under the action of a catalyst to generate acrolein.

[0014] After the first stage of reaction, the generated acrolein mixed gas is mixed with another air heated by the air preheater in the pipeline mixer B, which has the same structure as the pipeline mixer A, except that the pipeline mixer B has only two feed ports, which are located on the side wall and the upper wall respectively; after being mixed by the mixing element (passing through the porous plate, spiral blades, and porous plate in sequence), it enters the second oxidation reactor, where the oxidation reaction continues to occur under the action of the catalyst to obtain an acrylic acid mixed gas, which is transported to the next process through the bottom discharge port for separation and refining operations.

[0015] Compared with the prior art, the beneficial effects of the utility model are as follows: the multi-stage mixing type acrylic acid production homogenization device of the utility model realizes the full mixing of different reactants in multiple stages through the multi-stage mixer design, effectively improves the reaction efficiency and product quality, and at the same time, cooperates with the air preheater in the device to ensure that the reaction gas reaches a suitable temperature before entering the reactor, ensures the uniformity of the material temperature, reduces the probability of side reactions due to local overheating, and thus improves the reaction rate and selectivity; in addition, the spiral blades and porous plate structures are adopted inside the pipeline mixer to enhance the radial mixing of the fluid and further optimize the gas mixing effect, while the design of multiple feed ports provides a guarantee for dynamically adjusting the mixing conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of a multi-stage mixed acrylic acid production homogenization device of the utility model;

[0017] Figure 2 It is a side view of the pipeline mixer in the utility model;

[0018] Figure 3 It is a structural schematic diagram of the pipeline mixer of the utility model.

[0019] In the figure: 1. first oxidation reactor; 2. second oxidation reactor; 3. pipeline mixer A; 301. external shell; 302. feed port A; 303. feed port B; 304. feed port C; 305. spiral blade; 306. porous plate; 4. premixer; 5. air preheater; 6. turbine compressor; 7. air filter; 8. air pipeline; 9. propylene superheater; 10. propylene spherical tank; 11. steam pipeline; 12. circulating gas pipeline; 13. pipeline mixer B. DETAILED DESCRIPTION

[0020] The technical solution of the utility model is described in detail and clearly below in conjunction with the accompanying drawings.

[0021] like Figure 1-Figure 3 As shown, the multi-stage hybrid acrylic acid production homogenization device includes a first oxidation reactor 1 and a second oxidation reactor 2. The top feed port of the first oxidation reactor 1 is connected to a pipeline mixer A3, the pipeline mixer A3 is connected to a premixer 4, the premixer 4 is connected to an air preheater 5, and the feed port of the pipeline mixer A3 is provided with a pipeline connected to a propylene superheater 9; the first oxidation reactor 1 is connected to the feed port of the pipeline mixer B13 through a bottom discharge port, the pipeline mixer B13 discharge port is provided with a pipeline connected to the top of the second oxidation reactor 2, and the bottom of the second oxidation reactor 2 is provided with a discharge port to transport the reacted materials to the next process.

[0022] The feed port of the pipeline mixer A3 is connected to the circulating gas pipeline 12 , and the feed port of the premixer 4 is connected to the steam pipeline 11 .

[0023] The air inlet of the air preheater 5 is connected to the turbine compressor 6, the turbine compressor 6 is connected to the air filter 7, and the air filter 7 is connected to the air pipeline 8; the air preheater 5 is provided with a pipeline connected to the pipeline mixer B13.

[0024] The propylene superheater 9 is connected to the propylene spherical tank 10 .

[0025] The pipeline mixer A3 is composed of an external shell 301 and an internal mixing element. Three feed ports are arranged on one side of the feed port of the external shell 301. The feed port A302 is located on the side wall, and the feed port B303 and the feed port C304 are located on the upper and lower sides. The feed port A302 is used to convey a mixture of steam and air, the feed port B303 is used to convey propylene, and the feed port C304 is used to convey circulating gas. The external shell 301 is in a trumpet shape as a whole, and the feed port side is narrower than the discharge port side.

[0026] The feed inlet A302 and the feed inlet B303 both extend into the interior of the pipeline mixer A3 for a certain distance, and the gas outlets of the feed inlet A302 and the feed inlet B303 are spray gun structures.

[0027] The internal mixing elements are of two types: spiral blades 305 and porous plates 306. The porous plates 306 are located at the feed inlet and discharge outlet of the pipeline mixer A3, and the spiral blades 305 are located at other locations. The spiral blades 305 are connected to porous plates 306 before and after.

[0028] The pipeline mixer A3 and the pipeline mixer B13 have the same structure. The pipeline mixer B13 is provided with two feed ports, which are respectively located on the side wall and the upper wall. Its structure is the same as that of the feed ports A302 and B303 in the pipeline mixer A3.

[0029] The working process of the multi-stage hybrid acrylic acid production homogenization device is as follows: fresh air is dust-removed by an air filter 7 and then transported to a turbine compressor 6 through a pipeline. The compressed air enters an air preheater 5, which heats the air to a desired temperature and then is divided into two paths. One path of air is mixed with steam from a steam pipeline 11 and enters a premixer 4. After mixing, the air enters the next mixing section through a feed port A302 on the side wall of a pipeline mixer A3. A feed port B303 and a feed port C304 are also provided on one side of the feed port of the pipeline mixer A3, which are located at one end of the feed port, respectively. On the upper and lower walls of the side, the feed port B303 is used to transport propylene from the propylene superheater 9, and the feed port C304 is used to transport the circulating gas recycled from the reaction system to realize gas circulation; the feed port A302 and the feed port B303 are both spray gun structures to ensure that the two reaction gases can quickly transfer heat. The three raw materials are fully mixed through the mixing element arranged inside the pipeline mixer A3 (passing through the porous plate 306, the spiral blade 305, and the porous plate 306 in sequence), and enter the top of the first oxidation reactor 1. Under the action of the catalyst, a reaction occurs to generate acrolein.

[0030] After the first stage of reaction is completed, the generated acrolein mixed gas is discharged from the bottom of the first oxidation reactor 1, and mixed with another air heated by the air preheater 5 at the pipeline mixer B13. The pipeline mixer B13 has the same structure as the pipeline mixer A3, except that the pipeline mixer B13 has only two feed ports, which are located on the side wall and the upper wall respectively. After being mixed by the mixing element (passing through the porous plate 306, the spiral blade 305, and the porous plate 306 in sequence), it enters the second oxidation reactor 2, and continues to undergo oxidation reaction under the action of the catalyst to obtain an acrylic acid mixed gas, which is transported to the next process through the bottom discharge port for separation and refining operations.

Claims

1. A multi-stage hybrid acrylic acid production homogenization device, characterized in that: The invention comprises a first oxidation reactor (1) and a second oxidation reactor (2), wherein the top feed port of the first oxidation reactor (1) is connected to a pipeline mixer A (3), the pipeline mixer A (3) is connected to a premixer (4), the premixer (4) is connected to an air preheater (5), and the feed port of the pipeline mixer A (3) is provided with a pipeline connected to a propylene superheater (9); the first oxidation reactor (1) is connected to the feed port of a pipeline mixer B (13) through a bottom discharge port, the discharge port of the pipeline mixer B (13) is provided with a pipeline connected to the top of the second oxidation reactor (2), and the bottom of the second oxidation reactor (2) is provided with a discharge port to transport the reacted material to the next process.

2. The multi-stage hybrid acrylic acid production homogenization device according to claim 1, characterized in that: The feed port of the pipeline mixer A (3) is connected to the circulating gas pipeline (12), and the feed port of the premixer (4) is connected to the steam pipeline (11).

3. The multi-stage hybrid acrylic acid production homogenization device according to claim 1, characterized in that: The air inlet of the air preheater (5) is connected to the turbine compressor (6), the turbine compressor (6) is connected to the air filter (7), and the air filter (7) is connected to the air pipeline (8); the air preheater (5) is provided with a pipeline connected to the pipeline mixer B (13).

4. The multi-stage hybrid acrylic acid production homogenization device according to claim 1, characterized in that: The propylene superheater (9) is connected to the propylene spherical tank (10).

5. The multi-stage hybrid acrylic acid production homogenization device according to claim 1, characterized in that: The pipeline mixer A (3) is composed of an external shell (301) and an internal mixing element. Three feed ports are arranged on one side of the feed port of the external shell (301). The feed port A (302) is located on the side wall, and the feed ports B (303) and C (304) are located on the upper and lower sides. The feed port A (302) is used to transport a mixture of steam and air, the feed port B (303) is used to transport propylene, and the feed port C (304) is used to transport circulating gas. The external shell (301) is in a trumpet shape as a whole, and the feed port side is narrower than the discharge port side.

6. The multi-stage hybrid acrylic acid production homogenization device according to claim 5, characterized in that: The feed port A (302) and the feed port B (303) both extend into the interior of the pipeline mixer A (3) for a certain distance, and the gas outlets of the feed port A (302) and the feed port B (303) are spray gun structures.

7. The multi-stage hybrid acrylic acid production homogenization device according to claim 5, characterized in that: The internal mixing elements are of two types: spiral blades (305) and porous plates (306). The porous plates (306) are located at the feed inlet and the discharge outlet of the pipeline mixer A (3), and the spiral blades (305) are located at the other positions. The porous plates (306) are connected to the front and rear of the spiral blades (305).

8. The multi-stage hybrid acrylic acid production homogenization device according to claim 5, characterized in that: The pipeline mixer A (3) and the pipeline mixer B (13) have the same structure. The pipeline mixer B (13) is provided with two feed inlets, which are respectively located on the side wall and the upper wall of the pipeline mixer B (13). The structure of the two inlets is the same as that of the feed inlet A (302) and the feed inlet B (303) in the pipeline mixer A (3).

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