Ethylene oxide conversion reactor and method for improving conversion rate

Abstract

The invention discloses an ethylene oxide conversion reactor and a method for improving the conversion rate, and belongs to the field of ethylene oxide reactors, the ethylene oxide conversion reactor comprises: a reaction tank provided with an ethylene oxide inlet, a synthesis gas inlet and a catalyst inlet; the stirring shaft is rotatably arranged on the reaction tank, the stirring shaft is of a hollow structure, the top end of the stirring shaft is connected with a water conveying pipe, a water spraying pipe is arranged and serves as a stirring part when synthesis gas reacts with ethylene oxide, reaction of raw materials is facilitated, and when the interior of the tank needs to be cleaned, arc-shaped pipes at the two ends are attached to the shape of the reaction tank and pass through the reaction tank; water is injected into the stirring shaft through the water conveying pipe, flows to the transverse pipe along the stirring shaft of a hollow structure, then enters the vertical pipe and the arc-shaped pipe and finally is sprayed out of the water spraying opening to clean the interior of the reaction tank, the stirring shaft and the water spraying pipe are driven by the driving motor to rotate, and the water spraying pipe rotates to clean the interior of the reaction tank in all directions. And splashed water can be used for cleaning the stirring shaft and the water spraying pipe.

Description

Technical Field

[0001] The invention relates to the field of ethylene oxide reactors, and in particular to an ethylene oxide conversion reactor and a method for improving the conversion rate. Background Art

[0002] 1,3-Propanediol (PDO) is an important organic fine chemical. It can not only be used to produce antifreeze, plasticizers, preservatives and emulsifiers, but also widely used in food, cosmetics and pharmaceutical industries.

[0003] The process of producing PDO by ethylene oxide is mainly divided into two steps: first, ethylene oxide undergoes hydroformylation reaction with synthesis gas (mainly composed of hydrogen and carbon monoxide) under the action of a catalyst to produce 3-hydroxypropionaldehyde (HPA); then, HPA undergoes catalytic hydrogenation reaction to produce PDO. The key to this process lies in the efficiency and selectivity of the hydroformylation reaction, which directly affects the yield and production cost of PDO.

[0004] In the process of hydroformylation of ethylene oxide and synthesis gas to produce 3-hydroxypropionaldehyde (3-HPA), the cleaning of the reaction tank is an important link, which directly affects the efficiency of subsequent reactions and the purity of the product. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a water spray pipe installed on the stirring shaft. The water spray pipe cleans the inner wall of the reaction tank through the rotation of the stirring shaft. The water spray pipe acts as a stirring component when the synthesis gas reacts with ethylene oxide. In order to solve the above technical problems, the present invention is solved by the following technical solutions.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] An ethylene oxide conversion reactor comprises: a reaction tank, on which an ethylene oxide inlet, a synthesis gas inlet and a catalyst inlet are arranged; a stirring shaft, which is rotatably arranged on the reaction tank, the stirring shaft is of a hollow structure, the top of the stirring shaft is connected to a water pipe, and the water pipe is connected to a switch valve; a water spray pipe, which is arranged in the reaction tank, the water spray pipe comprises a horizontal pipe connected to the stirring shaft, the horizontal pipe is connected to a vertical pipe, both ends of the vertical pipe are connected to arc pipes that fit the upper and lower shapes of the reaction tank, and the vertical pipe and the arc pipe are evenly provided with water spray ports on the side facing the inner wall of the reaction tank.

[0008] Preferably, a plurality of the transverse tubes are arranged in the longitudinal direction, and the lowest transverse tube is connected to the bottom of the hollow structure of the stirring shaft.

[0009] Preferably, a disc is connected to the stirring shaft, and a lifting retaining ring is provided on the edge of the disc.

[0010] Preferably, the retaining ring is connected to two brackets extending toward the stirring shaft, the upper ends of the two brackets are connected by a ring body, and two support rods passing through the two brackets respectively are arranged in the reaction tank, and the two support rods are slidably connected to the corresponding brackets respectively.

[0011] Preferably, a support plate is fixed to the bottom of the support rod, a spring is sleeved on the support rod, and two ends of the spring are respectively connected to the bracket and the support rod.

[0012] Preferably, a push rod is fixed on the stirring shaft, a ball is connected to the top end of the push rod, a circular boss is fixed to the lower surface of the ring body, the circular boss has a guide surface for ball contact, and the guide surface includes an arc-shaped inclined surface and a plane connecting the two ends of the arc-shaped inclined surface.

[0013] Preferably, an inward guide plate contacting the disc is connected to the bracket, and one end of the inward guide plate contacts the inner annular surface of the retaining ring.

[0014] Preferably, a support bar is fixed to the other end of the inward guide plate, a diverter plate is connected to the support bar, and a guide groove is formed on the diverter plate.

[0015] Preferably, a fan blade facing upward is fixed on the stirring shaft below the disc.

[0016] Preferably, the method for improving the conversion rate of ethylene oxide is to mix the raw synthesis gas and ethylene oxide in a ratio of 2.3:1, the reaction temperature is 130° C., the reaction pressure is 12 MPaG, and the residence time of the reactants in the reaction tube is 2 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The water spray pipe is provided, which acts as a stirring component when the synthesis gas reacts with ethylene oxide, which is beneficial to the reaction of the raw materials. When the tank needs to be cleaned, the arc-shaped pipes at both ends fit the shape of the reaction tank, and water is injected into the stirring shaft through the water pipe. The water flows along the hollow structure of the stirring shaft to the horizontal pipe and then enters the vertical pipe and the arc pipe, and finally sprays out from the water spray port to clean the inside of the reaction tank. Then, the stirring shaft and the water spray pipe are rotated by the driving motor. The rotation of the water spray pipe cleans the inside of the reaction tank in all directions, and the splashing water can clean the stirring shaft and the water spray pipe.

[0019] The disc, the retaining ring, the inward guide plate, the diverter plate and the guide groove are arranged so that the catalyst falls intermittently while moving on the disc, which is beneficial to the reaction of the synthesis gas and ethylene oxide.

[0020] The fan blades arranged on the stirring shaft rotate with the stirring shaft, so that the airflow flows. The airflow and the airflow blown upward by the fan blades slow down the falling of the catalyst, which is beneficial to the reaction of ethylene oxide and synthesis gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0023] Figure 2 It is a schematic diagram of the internal structure of the reaction tank of the present invention.

[0024] Figure 3 For the present invention Figure 2 Enlarged schematic diagram at point A in the middle.

[0025] Figure 4 It is a schematic diagram of a water spray pipe of the present invention.

[0026] Figure 5 For the present invention Figure 4 Enlarged schematic diagram of point B in the middle.

[0027] Figure 6 It is a schematic cross-sectional view of the water spray pipe and the stirring shaft of the present invention.

[0028] Figure 7 It is a schematic diagram of the guide surface of the present invention.

[0029] Explanation of the figure numbers: 1. Reaction tank; 11. Tank body; 12. Tank cover; 13. Ethylene oxide inlet; 14. Synthesis gas inlet; 15. Catalyst inlet; 16. Jacket; 2. Agitator shaft; 21. Gear set; 22. Water pipe; 221. Switch valve; 23. Disc; 24. Push rod; 241. Ball bearing; 3. Water spray pipe; 31. Horizontal pipe; 32. Vertical pipe; 33. Arc pipe; 34. Water spray port; 4. Drive motor; 5. Retaining ring; 51. Bracket; 511. Ring body; 512. Circular boss; 513. Guide surface; 5131. Arc slope; 5132. Plane; 6. Support rod; 61. Support plate; 7. Spring; 8. Inward guide plate; 81. Support bar; 82. Diverter plate; 821. Diversion groove; 9. Fan blade. DETAILED DESCRIPTION

[0030] The present invention is described in further detail below with reference to the accompanying drawings.

[0031] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the present invention defined in the following description can be used for other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the present invention.

[0032] Those skilled in the art should understand that, in the disclosure of the present invention, the directions or positions indicated by the terms "longitudinal", "lateral", "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the simplified description of the present invention, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the above terms should not be understood as limiting the present invention.

[0033] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0034] See also Figure 1-Figure 7 , an ethylene oxide conversion reactor, comprising a reaction tank 1, a stirring shaft 2 and a water spray pipe 3, the reaction tank 1 comprises a tank body 11 and a tank cover 12, the tank cover 12 is provided with an ethylene oxide inlet 13, a synthesis gas inlet 14 and a catalyst inlet 15, etc., in addition, the tank cover 12 is also provided with a thermometer and a pressure gauge, a jacket 16 is provided on the surface of the tank body 11, a heating device is provided between the jacket 16 and the tank body 12, a cooling water inlet is provided on the lower side of the jacket 16, the jacket 16, the heating device and the cooling water inlet are prior art and will not be described again;

[0035] The stirring shaft 2 is rotatably arranged on the reaction tank 1, a gear set 21 is fixed on the upper end of the stirring shaft 2, a driving motor 4 is connected to the gear set 21, and the driving motor 4 is installed on the tank cover 12, the stirring shaft 2 is a hollow structure, a water pipe 22 is connected to the top of the stirring shaft 2, the water pipe 22 and the stirring shaft 2 are connected by a rotary joint, a switch valve 221 is connected to the water pipe 22, the switch valve 221 controls the communication between the water pipe 22 and the stirring shaft 2, and the switch valve 221 and the rotary joint are prior art;

[0036] The water spray pipe 3 is arranged in the reaction tank 1. A plurality of water spray pipes 3 can be arranged on the circumference of the stirring shaft 2. The present application takes two symmetrical ones as an example. The water spray pipe 3 includes a horizontal pipe 31 connected to the stirring shaft 2. The horizontal pipe 31 is connected to a vertical pipe 32. Both ends of the vertical pipe 32 are connected to arc pipes 33 that fit the upper and lower shapes of the reaction tank 1. The vertical pipe 32 and the arc pipe 33 are an integral structure. The vertical pipe 32 and the arc pipe 33 are evenly provided with water spray ports 34 on one side facing the inner wall of the reaction tank 1. Figure 6 As shown, a plurality of transverse tubes 31 are arranged in the longitudinal direction, and the lowest transverse tube 31 is connected to the bottom of the hollow structure of the stirring shaft 2, so that all water flows out from the stirring shaft 2, achieving the purpose of no water accumulation. The bottom of the lower arc tube 33 has a water spraying port 34, which also achieves the purpose of no water accumulation in the water spraying pipe 3. The lower side of the tank body 11 is provided with an outlet.

[0037] When cleaning is required, the switch valve 221 is opened first, and water is delivered to the stirring shaft 2 through the water delivery pipe 22. The water flows along the hollow structure of the stirring shaft 2 to the horizontal pipe 31 and then enters the vertical pipe 32 and the arc pipe 33, and finally sprays out from the water spray port 34 to clean the inside of the reaction tank 1. Then, the stirring shaft 2 and the water spray pipe 3 are rotated by the driving motor 4, and the water spray pipe 3 rotates to clean the inside of the reaction tank 1 in all directions. The splashing water can clean the stirring shaft 2 and the water spray pipe 3, and when ethylene oxide and synthesis gas react in the tank, the water spray pipe 3 follows the stirring shaft 2 and serves as a stirring rod.

[0038] As shown in the figure, a plurality of transverse tubes 31 are arranged in the longitudinal direction, and the lowest transverse tube 31 is connected to the bottom of the hollow structure of the stirring shaft 2, so that all water flows out of the stirring shaft 2, achieving the purpose of no water accumulation.

[0039] In order to make ethylene oxide and synthesis gas react better, a disc 23 is connected to the stirring shaft 2. The edge of the disc 23 is provided with a lifting and lowering retaining ring 5. The disc 23 is used to hold the catalyst. When the disc 23 rotates with the stirring shaft 2, the catalyst is thrown to the outside through centrifugal force. The movement of the catalyst is beneficial to the reaction of ethylene oxide and synthesis gas.

[0040] The retaining ring 5 is connected with two brackets 51 extending toward the stirring shaft 2. The lower end of the bracket 51 is fixed to the retaining ring 5. The upper ends of the two brackets 51 are connected through a ring body 511. The ring body 511 is sleeved on the stirring shaft 2 and does not rub against the stirring shaft 2. Two support rods 6 are respectively passed through the two brackets 51 in the reaction tank 1. The two support rods 6 stabilize the retaining ring 5. The two support rods 6 are slidably connected with the corresponding brackets 51, and the two support rods 6 enable the retaining ring 5 to move longitudinally. When the retaining ring 5 is separated from the disc 23, the catalyst on the disc 23 will fly upward, which is also beneficial to the reaction.

[0041] A support plate 61 is fixed to the bottom of the support rod 6, and a spring 7 is sleeved on the support rod 6. The two ends of the spring 7 are respectively connected to the bracket 51 and the support rod 6. A top rod 24 is fixed to the stirring shaft 2, and a ball 241 is connected to the top of the top rod 24. The ball 241 is conducive to reducing friction. A circular boss 512 is fixed to the lower surface of the ring body 511. The circular boss 512 has a guide surface 513 that the ball 241 contacts. The guide surface 513 includes an arc-shaped inclined surface 5131 and a plane 5132 connecting the two ends of the arc-shaped inclined surface 5131.

[0042] like Figure 7 As shown, the ball 241 on the push rod 24 is at the uppermost side of the arc-shaped inclined surface 5131, and the retaining ring 5 is at the lowermost side at this time. The stirring shaft 2 drives the push rod 24 to rotate. In the process of the push rod 24 rotating from the uppermost side of the arc-shaped inclined surface 5131 to the plane 5132, the circular boss 512 rises, bringing the bracket 51 up, and the bracket 51 rises with the retaining ring 5. When the ball 241 on the push rod 24 is located on the plane 5132, the retaining ring 5 is separated from the disc 23. When the ball 241 on the push rod 24 rotates on the plane 5132, the retaining ring 5 and the disc 23 remain separated.

[0043] The bracket 51 is connected with an inward guide plate 8 that contacts the disc 23. One end of the inward guide plate 8 contacts the inner ring surface of the retaining ring 5. The inward guide plate 8 guides the catalyst thrown outward to the inside. The other end of the inward guide plate 8 is fixed with a support bar 81. The support bar 81 is connected with a diverter plate 82. The diverter plate 82 disperses the catalyst. The diverter plate 82 is provided with a guide groove 821. The catalyst is more dispersed through the separation plate and the guide groove 821, which is beneficial to the reaction of ethylene oxide and synthesis gas in the tank. The stirring shaft 2 below the disc 23 is fixed with a fan blade 9 facing upward. The horizontal tube 31 above the fan blade 9 is provided with a water spray port 34 corresponding to the fan blade 9. When cleaning, the fan blade 9 is also cleaned. The fan blade 9 rotates with the stirring shaft 2 to make the air flow. The air flow and the air flow blown upward by the fan blade 9 slow down the catalyst from falling, which is beneficial to the reaction of ethylene oxide and synthesis gas.

[0044] A method for improving the conversion rate of ethylene oxide, wherein the raw material synthesis gas and ethylene oxide are mixed in a ratio of 2.3:1, the reaction temperature is 130°C, the reaction pressure is 12MPaG, and the residence time of the reactants in the reaction tube is 2h. When in use, firstly, a catalyst disc 23 is added into the tank, and the air is replaced by synthesis gas, and then the pressure is increased to a set value, and then ethylene oxide is added, the synthesis gas and ethylene oxide are added in a ratio of 2.3:1, and the reaction temperature and pressure are controlled so that the reaction is carried out under the set conditions, so that the conversion rate of ethylene oxide can stably reach more than 98%.

[0045] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are only examples and do not limit the present invention. The purpose of the present invention has been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and the embodiments of the present invention may be changed or modified without departing from the principles.

Claims

1. An ethylene oxide conversion reactor, characterized in that: include: A reaction tank (1) is provided with an ethylene oxide inlet (13), a synthesis gas inlet (14) and a catalyst inlet (15); A stirring shaft (2) is rotatably disposed on the reaction tank (1); the stirring shaft (2) is of a hollow structure; a top end of the stirring shaft (2) is connected to a water pipe (22); and a switch valve (221) is connected to the water pipe (22); A water spray pipe (3) is arranged in the reaction tank (1), the water spray pipe (3) comprising a horizontal pipe (31) connected to the stirring shaft (2), the horizontal pipe (31) being connected to a vertical pipe (32), both ends of the vertical pipe (32) being connected to arc-shaped pipes (33) fitting the upper and lower shapes of the reaction tank (1), and water spray ports (34) are evenly provided on one side of the vertical pipe (32) and the arc-shaped pipe (33) facing the inner wall of the reaction tank (1).

2. An ethylene oxide conversion reactor according to claim 1, characterized in that: A plurality of the transverse tubes (31) are arranged in the longitudinal direction, and the lowest transverse tube (31) is connected to the bottom of the hollow structure of the stirring shaft (2).

3. An ethylene oxide conversion reactor according to claim 1, characterized in that: The stirring shaft (2) is connected to a disc (23), and a lifting and lowering retaining ring (5) is provided on the edge of the disc (23).

4. An ethylene oxide conversion reactor according to claim 3, characterized in that: The retaining ring (5) is connected to two brackets (51) extending toward the stirring shaft (2); the upper ends of the two brackets (51) are connected via a ring body (511); and two support rods (6) passing through the two brackets (51) are arranged in the reaction tank (1); the two support rods (6) are slidably connected to the corresponding brackets (51) respectively.

5. An ethylene oxide conversion reactor according to claim 4, characterized in that: A support plate (61) is fixed to the bottom of the support rod (6), a spring (7) is sleeved on the support rod (6), and two ends of the spring (7) are respectively connected to the bracket (51) and the support rod (6).

6. An ethylene oxide conversion reactor according to claim 5, characterized in that: A push rod (24) is fixed on the stirring shaft (2), and a ball (241) is connected to the top end of the push rod (24). A circular boss (512) is fixed to the lower surface of the ring body (511), and the circular boss (512) has a guide surface (513) that contacts the ball (241), and the guide surface (513) includes an arc-shaped inclined surface (5131) and a plane (5132) connecting the two ends of the arc-shaped inclined surface (5131).

7. An ethylene oxide conversion reactor according to claim 6, characterized in that: An inward guide plate (8) that contacts the disc (23) is connected to the bracket (51), and one end of the inward guide plate (8) contacts the inner annular surface of the retaining ring (5).

8. An ethylene oxide conversion reactor according to claim 7, characterized in that: A support bar (81) is fixed to the other end of the inward guide plate (8), a flow diversion plate (82) is connected to the support bar (81), and a flow diversion groove (821) is provided on the flow diversion plate (82).

9. An ethylene oxide conversion reactor according to claim 6, characterized in that: A fan blade (9) facing upward is fixed on the stirring shaft (2) below the circular disc (23).

10. The method for improving the conversion rate of ethylene oxide according to any one of claims 1 to 9, characterized in that: The raw synthesis gas and ethylene oxide are mixed in a ratio of 2.3:1, the reaction temperature is 130°C, the reaction pressure is 12MPaG, and the residence time of the reactants in the reaction tube is 2h.

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