Solid maleic anhydride melting kettle for producing succinic acid by hydrogenation of maleic anhydride

Abstract

The utility model discloses a solid succinic anhydride melting kettle for succinic anhydride hydrogenation production butanedioic acid, including shell and set up on the steam jacket of shell outer wall, the inside of shell is divided into a plurality of melting cavities through cone, the lower extreme of each cone all is provided with orifice plate, and the bore diameter of orifice plate gradually becomes smaller from top to bottom, and the helical tube is provided in each melting cavity, and the helical tube in a plurality of melting cavities is connected in turn, and the top of sealing cavity is installed with motor, and the output shaft of motor is connected with hollow shaft after extending into sealing cavity, and the through hole is processed on the hollow shaft in sealing cavity, and the bottom of shell is sealed rotary connection with the lower extreme of hollow shaft, and the bottom of steam jacket is communicated with the lower extreme of hollow shaft, and the hollow shaft in each melting cavity all is provided with agitating rod, and the top of shell is provided with feed inlet. Above all, the utility model has the advantages of uniform heating, fast melting speed, and the advantage of continuous operation.

Description

Technical Field

[0001] This utility model relates to the field of solid maleic anhydride melting technology, specifically to a solid maleic anhydride melting kettle for the hydrogenation of maleic anhydride to produce succinic acid. Background Technology

[0002] Succinic acid, also known as maleic anhydride, is an important chemical raw material widely used in biodegradable plastics, food additives, pharmaceuticals, and chemical synthesis. Catalytic hydrogenation of maleic anhydride is one of the main industrial methods for producing succinic acid. In the process of producing succinic acid through the hydrogenation of maleic anhydride, solid maleic anhydride has a melting point of 52.8℃ and is crystalline at room temperature. Direct hydrogenation in the solid state presents challenges in mass transfer. Therefore, depending on the process conditions and production needs, solid maleic anhydride can be dissolved in water or an organic solvent for the reaction, or it can be melted and reacted in the molten state, which reduces solvent usage and energy consumption.

[0003] Melting solid maleic anhydride requires melting equipment. Current melting equipment suffers from several problems: First, most use external-to-internal heat conduction, causing the solid maleic anhydride near the inner wall to melt first, followed by heat conduction towards the center, resulting in a prolonged heating process and low efficiency. Second, most melting vessels operate intermittently, adding a certain amount of solid maleic anhydride, heating it, and then adding more after it has liquefied and been discharged. This intermittent melting process reduces efficiency and prolongs melting time. Therefore, developing a solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to succinic acid, which offers uniform heating, rapid melting, and continuous operation, is essential. Utility Model Content

[0004] The purpose of this invention is to provide a solid maleic anhydride melting kettle for the production of succinic acid by hydrogenation of maleic anhydride, which features uniform heating, fast melting speed, and continuous operation.

[0005] The purpose of this utility model is achieved as follows: it includes a shell and a steam jacket disposed on the outer wall of the shell. The interior of the shell is divided into multiple melting chambers by cones. Each cone has a perforated plate at its lower end, and the diameter of the perforation plate gradually decreases from top to bottom. Each melting chamber is provided with a spiral tube, and the spiral tubes in multiple melting chambers are connected in series. A sealing chamber is provided at the top of the shell, and a motor is installed at the top of the sealing chamber. The output shaft of the motor extends into the sealing chamber and is connected to a hollow shaft. A through hole is machined on the hollow shaft in the sealing chamber. The lower end of the hollow shaft is rotatably connected to the bottom of the shell and communicates with the bottom of the steam jacket. A stirring rod is provided on the hollow shaft in each melting chamber. A feed port is provided at the top of the shell.

[0006] Furthermore, each hollow shaft inside the melting chamber is equipped with a heat-conducting plate.

[0007] Furthermore, a condenser is connected to the top of the shell via an exhaust pipe. The condensate outlet of the condenser is connected to the top of the shell. Each cone is provided with an upper gas pipe that connects two adjacent melting chambers. The upper end of the upper gas pipe extends into the upper part of the previous melting chamber.

[0008] Furthermore, several heat-conducting rings are arranged at intervals on the inner wall of the shell.

[0009] Furthermore, each hollow shaft in the melting chamber is equipped with a scraper, the lower end face of which contacts the upper surface of the corresponding orifice plate.

[0010] Furthermore, a water-steam mixer and a steam generator are connected on the outside of the shell. The condensate outlet at the bottom of the steam jacket, the steam outlet of the steam jacket, the steam outlet of the spiral tube, and the steam outlet of the sealed cavity are all connected to the water-steam mixer through pipelines. The steam outlet of the steam generator is connected to the steam inlet of the spiral tube and the steam inlet of the steam jacket through pipelines.

[0011] Furthermore, a temperature sensor is installed in each melting chamber.

[0012] This invention relates to the melting of solid maleic anhydride during the hydrogenation of maleic anhydride to produce succinic acid. During operation, the motor is first started, driving the hollow shaft to rotate. The hollow shaft then drives the agitator rod to rotate. Simultaneously, steam is introduced into the steam jacket and the spiral tube. One stream of steam flows within the steam jacket, while another stream enters the hollow shaft from the lower end, flowing upwards within it before exiting through the sealed cavity. The final stream of steam enters the spiral tube, typically starting at the bottom and flowing upwards sequentially, finally exiting from the top. The spiral tube discharges steam, which preheats the internal space of the shell to a certain temperature. Then, solid maleic anhydride is added into the shell through the feed port. The solid maleic anhydride falls into the uppermost melting chamber, where it is heated by steam and melts continuously. The molten maleic anhydride and unmelted small particles of solid maleic anhydride pass through the orifice plate and fall into the next melting chamber. This process continues, with the solid maleic anhydride continuously melting into a liquid state and the unmelted solid maleic anhydride particles becoming smaller and smaller as they fall into the next melting chamber. Finally, all the molten maleic anhydride is discharged from the bottom melting chamber. In this invention, the steam is divided into three streams. One stream enters the steam jacket to heat the solid maleic anhydride from the outside. Another stream enters a spiral tube located in the middle of the shell, heating the solid maleic anhydride from the center. The last stream enters a hollow shaft located at the center of the shell, heating the solid maleic anhydride from the center. These three steam streams simultaneously heat the solid maleic anhydride from the outside, middle, and center. Compared to the traditional method of heat conduction only from the outside to the inside, this provides a larger heating surface for the solid maleic anhydride, allowing for simultaneous heating at multiple points, shortening the heating time, and improving the heating efficiency. Secondly... This invention incorporates a stirring rod, which serves two functions: firstly, it breaks down solid maleic anhydride, reducing its particle size and thus improving its melting efficiency; secondly, it agitates the maleic anhydride, ensuring it remains in a running state and improving the uniformity of heating, thereby enhancing its melting efficiency. Furthermore, during operation, new solid maleic anhydride can be continuously added to the uppermost melting chamber, while molten maleic anhydride continuously falls into the next melting chamber, finally exiting from the lowermost chamber. This process can be continuous, requiring only that the amount of solid maleic anhydride added and discharged be kept relatively constant, significantly improving the melting efficiency. In summary, this invention offers advantages such as uniform heating, rapid melting, and continuous operation. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0014] In the diagram: 1-Shell, 2-Steam jacket, 3-Cone, 4-Melting chamber, 5-Orifice plate, 6-Spiral tube, 7-Sealing chamber, 8-Motor, 9-Hollow shaft, 10-Stirring rod, 11-Feed inlet, 12-Heat-conducting plate, 13-Condenser, 14-Upper steam pipe, 15-Heat-conducting ring, 16-Scraper, 17-Water-steam mixer, 18-Steam generator, 19-Temperature sensor. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.

[0016] like Figure 1 As shown, this utility model includes a shell 1 and a steam jacket 2 disposed on the outer wall of the shell 1. The interior of the shell 1 is divided into multiple melting chambers 4 by cones 3. Each cone 3 has a perforated plate 5 at its lower end. The diameter of the perforations of the multiple perforated plates 5 gradually decreases from top to bottom. Each melting chamber 4 is provided with a spiral tube 6. The spiral tubes 6 in the multiple melting chambers 4 are connected in series. A sealing chamber 7 is provided at the top of the shell 1. A motor 8 is installed at the top of the sealing chamber 7. The output shaft of the motor 8 extends into the sealing chamber 7 and is connected to a hollow shaft 9. A through hole is machined on the hollow shaft 9 in the sealing chamber 7. The lower end of the hollow shaft 9 is rotatably connected to the bottom of the shell 1. The lower end of the hollow shaft 9 is connected to the bottom of the steam jacket 2. Each hollow shaft 9 in the melting chamber 4 is provided with a stirring rod 10. A feed inlet 11 is provided at the top of the shell 1.

[0017] This invention is used for melting solid maleic anhydride during the hydrogenation of maleic anhydride to produce succinic acid. During operation, motor 8 is first started, driving hollow shaft 9 to rotate. Hollow shaft 9 then drives stirring rod 10 to rotate. Simultaneously, steam is introduced into steam jacket 2 and spiral tube 6. One stream of steam flows within steam jacket 2, while another stream enters hollow shaft 9 from its lower end, flowing upwards within it before exiting through sealed cavity 7. The final stream of steam enters spiral tube 6, typically starting at the bottom and flowing upwards sequentially, finally exiting from the bottom. The steam from the upper spiral tube 6 preheats the internal space of the shell 1 to a certain temperature. Then, solid maleic anhydride is added into the shell 1 through the feed port 11. The solid maleic anhydride falls into the uppermost melting chamber 4 and is heated by the steam, continuously melting. The molten maleic anhydride and unmelted small solid maleic anhydride particles pass through the orifice plate 5 and fall into the next melting chamber 4. This process continues, with the solid maleic anhydride continuously melting into a liquid state. The unmelted solid maleic anhydride particles become smaller and smaller and fall into the next melting chamber 4. Finally, all the molten maleic anhydride is discharged from the bottommost melting chamber 4.

[0018] In this invention, the steam is divided into three streams. One stream enters the steam jacket 2 to heat the solid maleic anhydride from the outside. Another stream enters the spiral tube 6, which is located in the middle of the shell 1, and heats the solid maleic anhydride from the middle position. The last stream enters the hollow shaft 9, which is located in the center of the shell 1, and heats the solid maleic anhydride from the center position. The three steam streams heat the solid maleic anhydride simultaneously from the outside, middle, and center positions. Compared with the traditional method of heat conduction only from the outside to the inside, the solid maleic anhydride has a larger heating surface area, allowing for simultaneous heating at multiple points, shortening the heating time, and improving the heating efficiency. Secondly, This invention includes a stirring rod 10, which serves two purposes: firstly, it can break up solid maleic anhydride, reducing its particle size and thus improving its melting efficiency; secondly, it can agitate the maleic anhydride, keeping it in a running state and improving the uniformity of heating, thereby further enhancing its melting efficiency. Furthermore, during operation, new solid maleic anhydride can be continuously added to the uppermost melting chamber 4, while molten maleic anhydride continuously falls into the next melting chamber 4, finally being discharged from the lowermost melting chamber 4. The entire process can be continuous, requiring only that the amount of solid maleic anhydride added and discharged be kept roughly equal, significantly improving the melting efficiency of solid maleic anhydride.

[0019] Each hollow shaft 9 in the melting chamber 4 is equipped with a heat-conducting plate 12. The heat-conducting plate 12 is made of a material with good thermal conductivity and is used to conduct the heat of the steam in the hollow shaft 9, so as to conduct the heat of the steam to a farther location and improve the heat exchange efficiency between the steam and maleic anhydride.

[0020] A condenser 13 is connected to the top of the shell 1 via an exhaust pipe. The condenser 13 is an existing device used to condense the steam discharged from the top of the shell 1. The condensate outlet of the condenser 13 is connected to the top of the shell 1. Each cone 3 has an upper gas pipe 14 connecting two adjacent melting chambers 4. The upper end of the upper gas pipe 14 extends into the upper part of the previous melting chamber 4. In this invention, steam is used to heat and melt solid maleic anhydride. However, due to the characteristics of maleic anhydride, even if it does not melt, it will sublimate after prolonged exposure to 60-80°C, directly changing from a solid to a gaseous state, thus generating gas in each melting chamber 4. To discharge these gases in a timely manner, the upper gas pipe 14 is provided. The gaseous maleic anhydride rises continuously along the upper gas pipe 14 and is finally sent to the condenser 13 for condensation through the exhaust pipe. The condensed liquid maleic anhydride then flows back into the shell 1, effectively preventing the waste of maleic anhydride.

[0021] Several heat-conducting rings 15 are arranged at intervals on the inner wall of the shell 1. The heat-conducting rings 15 are made of a material with good thermal conductivity, which can transfer the steam heat in the steam jacket 2, increase the heat transfer area of ​​the steam, and thus improve the heating efficiency of steam and maleic anhydride.

[0022] Each hollow shaft 9 within the melting chamber 4 is equipped with a scraper 16, the lower end face of which contacts the upper surface of the corresponding orifice plate 5. The scraper 16 is mounted on the hollow shaft 9 and rotates with it. In actual use, the scraper 16 scrapes the orifice plate 5, removing solid maleic anhydride particles adhering to the through holes of the orifice plate 5, ensuring smooth passage of maleic anhydride through the orifice plate 5 and preventing blockage.

[0023] A water-steam mixer 17 and a steam generator 18 are connected on the outer side of the housing 1. The condensate outlet at the bottom of the steam jacket 2, the steam outlet of the steam jacket 2, the steam outlet of the spiral tube 6, and the steam outlet of the sealed cavity 7 are all connected to the water-steam mixer 17 via pipelines. The steam outlet of the steam generator 18 is connected to the steam inlet of the spiral tube 6 and the steam inlet of the steam jacket 2 via pipelines. The water-steam mixer 17 and the steam generator 18 are existing equipment. The water-steam mixer 17 is used to mix water vapor and hot water to average their temperatures, which facilitates the subsequent steam production by the steam generator 18. In this invention, the steam and condensate discharged from the steam jacket 2, as well as the steam discharged from the spiral tube 6 and the sealed cavity 7, all contain a certain amount of heat. Passing them into the steam generator 18 to produce steam can reduce heat loss, improve heat utilization, and reduce the energy consumption of the steam generator 18 in producing steam.

[0024] Each melting chamber 4 is equipped with a temperature sensor 19, which is an existing instrument used to detect the temperature of maleic anhydride in each melting chamber 4, to prevent the temperature from being too high or too low, and to ensure the melting efficiency of solid maleic anhydride.

Claims

1. A solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to produce succinic acid, comprising a shell (1) and a steam jacket (2) disposed on the outer wall of the shell (1), characterized in that: The interior of the shell (1) is divided into multiple melting chambers (4) by cones (3). Each cone (3) has a perforated plate (5) at its lower end. The diameter of the perforated plates (5) gradually decreases from top to bottom. Each melting chamber (4) is equipped with a spiral tube (6). The spiral tubes (6) in the multiple melting chambers (4) are connected in series. The top of the shell (1) is equipped with a sealing chamber (7). A motor (8) is installed on the top of the sealing chamber (7). The output shaft of the motor (8) extends into the sealing chamber (7) and is connected to a hollow shaft (9). The hollow shaft (9) in the sealing chamber (7) has a through hole. The lower end of the hollow shaft (9) is sealed and rotatably connected to the bottom of the shell (1). The lower end of the hollow shaft (9) is connected to the bottom of the steam jacket (2). Each hollow shaft (9) in the melting chamber (4) is equipped with a stirring rod (10). The top of the shell (1) is equipped with a feed inlet (11).

2. The solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to produce succinic acid according to claim 1, characterized in that: Each molten cavity (4) has a heat-conducting plate (12) installed on the hollow shaft (9).

3. The solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to produce succinic acid according to claim 1, characterized in that: The top of the shell (1) is connected to a condenser (13) via an exhaust pipe. The condensate outlet of the condenser (13) is connected to the top of the shell (1). Each cone (3) is provided with an upper air pipe (14) that connects two adjacent melting chambers (4). The upper end of the upper air pipe (14) extends into the upper part of the previous melting chamber (4).

4. The solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to produce succinic acid according to claim 1, characterized in that: The inner wall of the housing (1) is provided with several heat-conducting rings (15) spaced vertically.

5. The solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to produce succinic acid according to claim 1, characterized in that: Each hollow shaft (9) in the melting chamber (4) is provided with a scraper (16), and the lower end face of the scraper (16) is in contact with the upper surface of the corresponding orifice plate (5).

6. The solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to produce succinic acid according to claim 1, characterized in that: The outer side of the housing (1) is provided with a water-steam mixer (17) and a steam generator (18). The condensate outlet at the bottom of the steam jacket (2), the steam outlet of the steam jacket (2), the steam outlet of the spiral tube (6) and the steam outlet of the sealing cavity (7) are all connected to the water-steam mixer (17) through pipelines. The steam outlet of the steam generator (18) is connected to the steam inlet of the spiral tube (6) and the steam inlet of the steam jacket (2) through pipelines respectively.

7. The solid maleic anhydride melting vessel for the hydrogenation of maleic anhydride to produce succinic acid according to claim 1, characterized in that: Each melting chamber (4) is equipped with a temperature sensor (19).

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