Synthesis device and synthesis method for synthesizing butyraldehyde through propylene hydroformylation

Abstract

The invention discloses a synthesis device and a synthesis method for synthesizing butyraldehyde through propylene hydroformylation, and relates to the technical field of organic chemical industry. Comprising a propylene pipeline, a synthetic gas pipeline, a hydrogen pipeline, a first reaction kettle, a second reaction kettle, a flash evaporator, an absorption tower, a desorption tower, a rectifying tower, a separator and a compressor, the propylene pipeline is communicated with the first reaction kettle, the hydrogen pipeline is connected with the synthetic gas pipeline, and the synthetic gas pipeline is communicated with the first reaction kettle and the second reaction kettle; the first reaction kettle comprises a first gas distributor arranged at the bottom, and the second reaction kettle comprises a second gas distributor arranged at the bottom. The circulating pump and the cooler are arranged outside the reaction kettle for synthesizing butyraldehyde through propylene hydroformylation, traditional mechanical stirring is changed into fluid stirring, vented tail gas is separated and recycled, the operation period of the reaction kettle is prolonged, and the shutdown maintenance cost is reduced; the utilization rate of propane and propylene resources is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of organic chemical industry, in particular to a synthesis device and a synthesis method for synthesizing butyraldehyde by hydroformylation of propylene. Background Art

[0002] Butyraldehyde is an important chemical raw material, mainly used as an intermediate for resins, plasticizers, vulcanization accelerators, pesticides, etc. Butyraldehyde is mainly synthesized by propylene hydroformylation. The traditional process for synthesizing butyraldehyde from propylene hydroformylation (see Appendix Figure 1 ) Mechanical stirring is used, and the stirrer must be equipped with a mechanical seal. Due to the large size of the stirrer, it is easy to cause eccentricity, dynamic imbalance, short service life of the mechanical seal and other problems, and frequent inspection and maintenance are required. On the other hand, the exhaust gas from the hydroformylation of propylene to butyraldehyde contains a certain amount of propylene and propane. The traditional process is to directly discharge it into the flare system for incineration after cooling, which seriously wastes resources and has high production costs. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method and a synthesis device for synthesizing butyraldehyde by hydroformylation of propylene, which adopts fluid stirring instead of mechanical stirring, thereby extending the operation cycle of the reactor and reducing the cost of shutdown inspection and maintenance; the vented tail gas is recycled to improve the resource utilization efficiency of propane and propylene and reduce production costs.

[0004] To achieve the above object, the present invention provides the following technical solution: a synthesis device and a synthesis method for synthesizing butyraldehyde by hydroformylation of propylene, comprising: Propylene pipeline, synthesis gas pipeline, hydrogen pipeline, first reactor, second reactor, flash evaporator, absorption tower, analysis tower, distillation tower, separator and compressor; The propylene pipeline is connected to the first reactor, the hydrogen pipeline is connected to the synthesis gas pipeline, and the synthesis gas pipeline is connected to the first reactor and the second reactor; The first reactor includes a first gas distributor disposed at the bottom, the second reactor includes a second gas distributor disposed at the bottom, the top and bottom of the first reactor are respectively provided with a feed port N3 and a feed port N1, and the top and bottom of the second reactor are respectively provided with a feed port N4 and a feed port N5; A discharge port N2 is provided at the middle upper part of the first reactor, and the discharge port N2 is connected to a first cooler via a first circulation pump; a discharge port N7 is provided at the middle upper part of the second reactor, and the discharge port N7 is connected to a second cooler via a second circulation pump; A discharge port N6 is provided at the top of the second reactor, and a flash evaporator is connected to the discharge port N6, which is also connected to the separator.

[0005] Furthermore, with regard to this solution, both the first gas distributor and the second gas distributor are three-layer gas distributors, and the size, number and direction of the openings of the distributors are optimized to make the synthesis gas more evenly distributed in the reactor.

[0006] Further to this solution, a second reactor gas outlet pipeline is arranged at the top of the second reactor, and a compressor is also arranged on the pipeline of the second reactor gas outlet pipeline, and the compressor is connected to the separator and the second reactor.

[0007] Further to this scheme, the separator is provided with a pipeline connected to the absorption tower, a pipeline is provided between the absorption tower and the analysis tower, a pipeline is provided between the analysis tower and the distillation tower, a pipeline is provided between the separator and the analysis tower, and a pipeline is provided at the distillation tower to connect to the propylene pipeline.

[0008] A method for synthesizing butyraldehyde by hydroformylation of propylene, and a device for synthesizing butyraldehyde by hydroformylation of propylene, comprising the following steps: Step 1: Propylene enters the first reactor through the propylene pipeline via the flow feed port N1, synthesis gas and hydrogen enter the first reactor through the synthesis gas pipeline via the flow first gas distributor, and the circulating mother liquid after flash evaporation enters the first reactor through the flow feed port N3; Step 2: After the propylene, synthesis gas and hydrogen react in the first reactor, they enter the first cooler from the outlet N2 through the first circulation pump; Step 3: Propylene, synthesis gas and hydrogen are returned to the first reactor through the feed port N3 after heat exchange in the first cooler; Step 4: The gas is discharged from the gas outlet on the top of the first reactor and enters the second reactor through the second gas distributor; Step 5: The liquid in the first reactor passes through the first circulation pump and enters the second reactor from the bottom feed port N5 of the second reactor; Step 6: The reaction liquid in the second reactor enters the second cooler from the discharge port N7 through the second circulation pump; Step 7: After heat exchange, the reaction liquid returns to the second reactor through the feed port N4 arranged at the top of the second reactor; Step 8: The gas in the second reactor is discharged through the top gas outlet and enters the absorption tower through the second reactor gas outlet pipeline for treatment; Step 9: The reaction liquid in the second reactor enters the flash evaporator through the discharge port N6 set in the upper part of the second reactor, and the liquid treated by the flash evaporator returns to the first reactor through the feed port N1, and the gas enters the separator; Step 10: The gas discharged from the second reactor enters the absorption tower and is absorbed by the mixed butyraldehyde. The gas is discharged from the gas outlet pipeline of the absorption tower, and the mixed liquid enters the analytical tower from the bottom of the absorption tower; Step 11: The mixed liquid enters the analytical tower for separation, the separated propylene and propane mixture enters the distillation tower, and butyraldehyde is discharged from the bottom of the analytical tower; Step 12: After being processed in the distillation tower, propane is discharged from the bottom outlet, and propylene is discharged from the top of the distillation tower into the propylene pipeline; Step 13: After being treated by the separator, the gas is compressed by the compressor and enters the gas outlet pipeline of the second reactor. Part of the butyraldehyde enters the absorption tower, and part is discharged from the bottom of the separator.

[0009] Further to this scheme, in the step one, the flow rate of propylene entering the first reactor is controlled to be 10m-15m / s, the gas flow rate of the synthesis gas and hydrogen entering the first reactor through the synthesis gas pipeline through the first gas distributor is controlled to be 20m-50m / s, and in the step four, the flow rate of propylene, synthesis gas and hydrogen returning to the first reactor through the feed port N3 is controlled to be 10m-15m / s.

[0010] Further to this solution, the angle between the fluid injection angle of the feed port N1 and the feed port N3 toward the first reactor and the horizontal line is set to 0°-45°, and the angle between the discharge port N2 and the feed port N3 and the horizontal plane is set to 90°-180°.

[0011] Furthermore, regarding this solution, a secondary line is provided on the first cooler, and a flow regulation control is added to control the temperature of the first reactor by regulating the flow of the reaction liquid of the first cooler and the flow of the reaction liquid of the secondary line of the first cooler.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention arranges a circulation pump and a cooler outside the propylene hydroformylation butyraldehyde synthesis reactor, replaces the traditional mechanical stirring with fluid stirring, separates and recovers the vented tail gas, prolongs the operation cycle of the reactor, reduces the shutdown and maintenance cost; and improves the utilization rate of propane and propylene resources, reducing the production cost; At the same time, the material flow rate of the inlet pipeline for propylene hydroformylation to synthesize butyraldehyde into the reactor is adjusted to 10-15m / s, the orientation of the reactor inlet pipeline orifice is distributed at a certain angle, a three-layer distributor is used to distribute the synthesis gas into the reactor, the orientation of the reactor discharge pipeline orifice is at a certain angle to the orientation of the pipeline into the reactor after circulating cooling, the traditional mechanical stirring is changed to fluid stirring, and the vented tail gas is separated and recovered, which extends the operation cycle of the reactor and reduces the shutdown and maintenance costs; and improves the utilization rate of propane and propylene resources to reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the structure of the improved process flow of the present invention; Figure 2It is a schematic diagram of the structure of the distributor of the present invention; Figure 3 It is a schematic diagram of the structure of the nozzle in the distributor of the present invention; Figure 4 It is a schematic diagram of the cross-sectional structure of the nozzle of the present invention.

[0014] In the figure: 1, first reactor; 11, first circulation pump; 12, first cooler; 13, first gas distributor; 2, second reactor; 21, second circulation pump; 22, second cooler; 23, second gas distributor; 24, second reactor outlet pipeline; 3, flash evaporator; 4, absorption tower; 41, absorption tower outlet pipeline; 5, analytical tower; 6, distillation tower; 7, separator; 8, compressor; 9, synthesis gas pipeline; 91, hydrogen pipeline; 10, propylene pipeline; 14. Annular pipe; 15. Nozzle; 151. Horizontal pipe; 152. Damping bearing; 153. Nozzle pipe; 154. Side plate; 155. Nut sleeve; 156. Fork-shaped opening; 157. Sleeve; 158. Outlet; 159. Plug; 160. Spring; 161. Cover plate; 162. Partition; 163. Conical mouth; 164. Hanging rod; 16. Connecting pipeline. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] See also Figure 1 The embodiment of the present invention provides a synthesis device and a synthesis method for synthesizing butyraldehyde by hydroformylation of propylene, comprising a first reactor 1, a second reactor 2, a flash evaporator 3 and an absorption tower 4. A feed port N1 is provided at the bottom of the first reactor 1, and the feed port N1 is connected to a propylene pipeline 10.

[0017] A first gas distributor 13 is arranged at the lower part of the first reactor 1. The first gas distributor 13 is a three-layer gas distributor. The size, number and direction of the openings are more reasonable, so that the gas is more evenly distributed in the reactor. The gas distributor has three layers, and the opening form of the distributor adopts an X-shaped distribution. The size of the opening is determined according to the height requirement of the liquid layer of the reactor, and the number of openings is determined according to the flow rate of the synthesis gas required for the production capacity. The design will also change with the change of the production capacity of each set of equipment. The first gas distributor 13 is connected to the synthesis gas pipeline 9 and the hydrogen pipeline 91.

[0018] like Figure 2As shown, specifically, the first gas distributor 13 includes a ring pipe 14, a nozzle 15 and a connecting pipe 16, and the connecting pipe 16 is connected to the propylene pipe 10; like Figure 2 and Figure 3 As shown, the nozzle 15 includes a transverse tube 151, a nozzle tube 153 is fixed on the surface of the transverse tube 151, the nozzle tube 153 is a copper tube and a fork-shaped opening 156 is provided away from the transverse tube 151, the fork-shaped opening 156 is expanded, and a thread is provided on the surface of the nozzle tube 153 from the fork-shaped opening 156, and a nut sleeve 155 is screwed on the thread, that is, the diameter of the fork-shaped opening 156 can be changed, and when the nut sleeve 155 is screwed to the fork-shaped opening 156, the diameter of the opening becomes narrower, and the escape mode of the airflow can be controlled in this way; like Figure 3 and Figure 4 As shown, two side plates 154 are fixed on the horizontal tube 151, and a sleeve 157 is fixed between the two side plates 154. The sleeve 157 is provided with an outlet 158 ​​for gas escape. The length of the sleeve 157 is 5 cm-30 cm. The inner wall of the sleeve 157 near the nozzle tube 153 is provided with a partition 162. The partition 162 is used to separate the two sides of the partition 162. A hole is provided in the middle of the partition 162. 7 is provided with a plug 159, a protrusion is provided in the middle of the plug 159 and the protrusion is inserted into the hole, a cover plate 161 is provided at the end of the sleeve 157 away from the nozzle tube 153, a hanging rod 164 is fixed to the bottom of the cover plate 161 and the hanging rod 164 slides on the inner wall of the sleeve 157, a spring 160 is provided between the cover plate 161 and the plug 159, and conical openings 163 are provided on both sides of the partition 162 for guiding the airflow.

[0019] The first gas distributor 13 can achieve a suitable mixing effect by adjusting the size of the air flow. When the liquid level in the kettle is relatively low, the opening of the first gas distributor 13 is relatively large, so that the air flow can be directly ejected from the nozzle tube 153. The force of the air flow is not enough to push open the plug 159. In other words, the air flow will directly diffuse at the nozzle tube 153. With the cooperation of multiple nozzles 15, the gas can be evenly diffused in the liquid. When the liquid level in the kettle is high, the opening of the first gas distributor 13 is adjusted to the minimum to increase the air flow speed. The gas ejected from the nozzle tube 153 will impact the plug 159 at a very high speed. Due to the high-speed impact, the plug 159 is impacted open, and the gas backflow can be avoided under the action of the spring 160. In this case, the gas will impact upward and quickly reach the top liquid level in the kettle to improve the mixing effect.

[0020] What needs to be understood about the above embodiment is that the transverse tubes 151 are connected via the annular tube 14 , and the transverse tube 151 and the annular tube 14 are connected via the damping bearing 152 , which can adjust the angle of the nozzle 15 while allowing the nozzle 15 to output a stable airflow.

[0021] A discharge port N2 is provided at the upper part of the first reactor 1, and the discharge port N2 is connected to the first circulation pump 11, and the first circulation pump 11 is connected to the first cooler 12. The first cooler 12 is connected to the feed port N3 provided at the top of the first reactor 1, and the angle between the feed port N1 and the feed port N3 is 0°-45°; the angle between the discharge port N2 and the feed port N3 is 90°-180°. This method can form turbulence at the discharge port N2 and the feed port N3 to achieve a better stirring effect and make the materials mixed more evenly. A gas outlet is provided at the top of the first reactor 1; a secondary line is provided on the first cooler 12, and a flow regulation control is added. The temperature of the first reactor 1 is controlled by adjusting the flow of the reaction liquid of the first cooler 12 and the flow of the reaction liquid of the secondary line of the first cooler 12.

[0022] like Figure 1 As shown, a feed port N5 is provided at the bottom of the second reactor 2, and the feed port N5 is connected to the discharge port of the first circulation pump 11. A second gas distributor 23 is provided at the lower part of the second reactor 2. The second gas distributor 23 and the first gas distributor 13 adopt the same structure. The second gas distributor 23 is connected to the gas outlet at the top of the first reactor 1, the synthesis gas pipeline 9 and the hydrogen pipeline 91. A discharge port N7 is provided at the upper part of the second reactor 2, and the discharge port N7 is connected to the second circulation pump 21. The second circulation pump 21 is connected to the second cooler 22. The second cooler 22 is connected to the The feed port N4 is connected, and the angle between the feed port N4 and the feed port N5 is 0°-45°; a secondary line is set on the second cooler 22, and a flow adjustment control is added. The temperature of the second reactor 2 is controlled by adjusting the flow of the reaction liquid of the second cooler 22 and the flow of the reaction liquid of the secondary line of the second cooler 22. A discharge port N6 is also set in the middle and upper part of the second reactor 2. The angle between the discharge port N6 and the feed port N5 is 90°-180°. The discharge port N6 is connected to the flash evaporator 3. The bottom discharge port of the flash evaporator 3 is connected to the feed port N1 of the first reactor 1, and the top discharge port of the flash evaporator 3 is connected to the separator 7.

[0023] like Figure 1As shown, a gas outlet is provided at the top of the second reactor 2, and the gas outlet is connected to the second reactor gas outlet pipeline 24, and the second reactor gas outlet pipeline 24 is connected to the absorption tower 4. An absorption tower gas outlet pipeline 41 is provided at the top of the absorption tower 4, and the absorption tower gas outlet pipeline 41 can be directly discharged to the fuel gas pipeline network for use as external fuel gas, and can also be returned to the carbonyl synthesis reactor after compression treatment. The bottom discharge port of the absorption tower 4 is connected to the analysis tower 5, and the bottom of the analysis tower 5 is provided with a discharge port. The upper discharge port of the analysis tower 5 is connected to the distillation tower 6, and the bottom of the distillation tower 6 is provided with a discharge port. The upper discharge port of the distillation tower 6 is connected to the propylene pipeline 10, and the upper discharge port of the separator 7 is connected to the compressor 8, and the compressor 8 is connected to the second reactor gas outlet pipeline 24, and the bottom discharge port of the separator 7 is connected to the absorption tower 4.

[0024] The embodiment of the present invention provides a method for synthesizing butyraldehyde by hydroformylation of propylene, comprising the following steps: S1: Propylene enters the first reactor 1 through the propylene pipeline 10 via the flow feed port N1, synthesis gas and hydrogen enter the first reactor 1 through the synthesis gas pipeline 9 via the flow first gas distributor 13, and the circulating mother liquid after flashing enters the reactor through the flow feed port N3 (it should be understood that the circulating mother liquid is the butyraldehyde and reaction liquid separated by flashing after hydroformylation, that is, in the equipment startup stage, there is no circulating mother liquid in the first reactor 1), the flow rate of propylene entering the first reactor 1 is controlled to be 10m-15m / s, and the gas flow rate of synthesis gas and hydrogen entering the first reactor 1 through the synthesis gas pipeline 9 via the flow first gas distributor 13 is controlled to be 20m-50m / s; S2: After the reaction in the first reactor 1, propylene, synthesis gas and hydrogen enter the first cooler 12 from the discharge port N2 through the first circulation pump 11. The temperature of the first reactor 1 is controlled by adjusting the flow rate of the reaction liquid in the first cooler 12 and the flow rate of the reaction liquid in the secondary line of the first cooler 12.

[0025] S3: Propylene, synthesis gas and hydrogen are returned to the first reactor 1 through the feed port N3 after heat exchange in the first cooler 12. The flow rate of propylene, synthesis gas and hydrogen returning to the first reactor 1 through the feed port N3 is controlled to be 10m-15m / s; S4: gas (the gas phase coming out of the top of the first reactor 1 directly enters the second gas distributor 23 at the bottom of the second reactor 2 as the gas phase feed of the second reactor 2) is discharged from the gas outlet at the top of the first reactor 1 and enters the second reactor 2 through the second gas distributor 23; S5: The liquid in the first reactor 1 enters the second reactor 2 from the bottom feed port N5 of the second reactor 2 after passing through the first circulation pump 11. The flow rate of the liquid entering the second reactor 2 from the feed port N5 is controlled to be 10m-15m / s; S6: The reaction liquid in the second reactor 2 enters the second cooler 22 from the discharge port N7 through the second circulation pump 21; S7: After heat exchange, the reaction liquid returns to the second reactor 2 through the feed port N4 set at the top of the second reactor 2. The flow rate of the liquid after heat exchange entering the second reactor 2 through the feed port N4 is controlled to be 10m-15m / s. The temperature of the second reactor 2 is controlled by adjusting the flow rate of the reaction liquid in the second cooler 22 and the flow rate of the reaction liquid in the secondary line of the second cooler 22; S8: The gas in the second reactor 2 is discharged through the top gas outlet and enters the absorption tower 4 through the second reactor gas outlet pipeline 24 for treatment; S9: the reaction liquid in the second reactor 2 enters the flash evaporator 3 through the discharge port N6 arranged at the upper part of the second reactor 2, the liquid (flash mother liquid) treated by the flash evaporator 3 returns to the first reactor 1 through the feed port N1, and the gas enters the separator 7 from the top of the second reactor 2; S10: The gas discharged from the second reactor 2 enters the absorption tower 4, and is absorbed by the mixed butyraldehyde. The gas is discharged from the absorption tower outlet pipeline 41, and the mixed liquid enters the analytical tower 5 from the bottom of the absorption tower 4; S11: the mixed liquid enters the analytical tower 5 for separation, the separated propylene and propane mixture enters the distillation tower 6, and butyraldehyde is discharged from the bottom of the analytical tower 5; S12: After being processed by the distillation tower 6, propane is discharged from the bottom outlet, and propylene is discharged from the top of the distillation tower 6 into the propylene pipeline 10; S13: After being processed by the separator 7, the gas is compressed by the compressor 8 and enters the gas outlet pipeline 24 of the second reactor. Part of the butyraldehyde enters the absorption tower 4, and part is discharged from the bottom of the separator 7.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the attached embodiments and their equivalents.

Claims

1. A synthesis device for synthesizing butyraldehyde by hydroformylation of propylene, characterized in that: include: A propylene pipeline (10), a synthesis gas pipeline (9), a hydrogen pipeline (91), a first reaction kettle (1), a second reaction kettle (2), a flash evaporator (3), an absorption tower (4), a desorption tower (5), a distillation tower (6), a separator (7), and a compressor (8); The propylene pipeline (10) is connected to the first reaction kettle (1), the hydrogen pipeline (91) is connected to the synthesis gas pipeline (9), and the synthesis gas pipeline (9) is connected to the first reaction kettle (1) and the second reaction kettle (2); The first reactor (1) comprises a first gas distributor (13) arranged at the bottom, the second reactor (2) comprises a second gas distributor (23) arranged at the bottom, the top and bottom of the first reactor (1) are respectively provided with a feed port N3 and a feed port N1, and the top and bottom of the second reactor (2) are respectively provided with a feed port N4 and a feed port N5; A discharge port N2 is provided at the middle upper part of the first reaction kettle (1), and the discharge port N2 is connected to a first cooler (12) via a first circulation pump (11); a discharge port N7 is provided at the middle upper part of the second reaction kettle (2), and the discharge port N7 is connected to a second cooler (22) via a second circulation pump (21); A discharge port N6 is provided at the top of the second reaction kettle (2), and a flash evaporator (3) is connected to the discharge port N6. The flash evaporator (3) is also connected to the separator (7).

2. The synthesis device for synthesizing butyraldehyde by hydroformylation of propylene according to claim 1, characterized in that: The first gas distributor (13) and the second gas distributor (23) are both three-layer gas distributors, and the size, number and direction of the openings of the distributors are optimized to make the synthesis gas more evenly distributed in the reactor.

3. The synthesis device for synthesizing butyraldehyde by hydroformylation of propylene according to claim 1, characterized in that: A second reactor gas outlet pipeline (24) is provided at the top end of the second reactor (2), and a compressor (8) is also provided on the pipeline of the second reactor gas outlet pipeline (24), and the compressor (8) is connected to the separator (7) and the second reactor (2).

4. The synthesis device for synthesizing butyraldehyde by hydroformylation of propylene according to claim 1, characterized in that: The separator (7) is provided with a pipeline connected to the absorption tower (4), the absorption tower (4) is connected to the analysis tower (5) by a pipeline, the analysis tower (5) is connected to the distillation tower (6) by a pipeline, the separator (7) is connected to the analysis tower (5), and the distillation tower (6) is connected to the propylene pipeline (10).

5. A method for synthesizing butyraldehyde by hydroformylation of propylene, using the synthesis device for synthesizing butyraldehyde by hydroformylation of propylene according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: Propylene enters the first reactor (1) through the propylene pipeline (10) via the flow feed port N1, synthesis gas and hydrogen enter the first reactor (1) through the synthesis gas pipeline (9) via the flow first gas distributor (13), and the circulating mother liquid after flash evaporation enters the first reactor (1) via the flow feed port N3; Step 2: Propylene, synthesis gas and hydrogen react in the first reactor (1) and then enter the first cooler (12) from the outlet N2 through the first circulation pump (11); Step 3: Propylene, synthesis gas and hydrogen are returned to the first reactor (1) through the feed port N3 after heat exchange in the first cooler (12); Step 4: The gas is discharged from the gas outlet at the top of the first reaction kettle (1) and enters the second reaction kettle (2) through the second gas distributor (23); Step 5: the liquid in the first reactor (1) passes through the first circulation pump (11) and enters the second reactor (2) from the bottom feed port N5 of the second reactor (2); Step 6: The reaction liquid in the second reaction kettle (2) enters the second cooler (22) from the discharge port N7 through the second circulation pump (21); Step 7: After heat exchange, the reaction liquid is returned to the second reaction kettle (2) through the feed port N4 arranged at the top of the second reaction kettle (2); Step 8: The gas in the second reaction kettle (2) is discharged through the top gas outlet and enters the absorption tower (4) through the second reaction kettle gas outlet pipeline (24) for treatment; Step 9: the reaction liquid in the second reactor (2) enters the flash evaporator (3) through the discharge port N6 arranged at the upper middle part of the second reactor (2), the liquid treated in the flash evaporator (3) returns to the first reactor (1) through the feed port N1, and the gas enters the separator (7); Step 10: the gas discharged from the second reaction kettle (2) enters the absorption tower (4) and is absorbed by the mixed butyraldehyde. The gas is discharged from the absorption tower outlet pipeline (41), and the mixed liquid enters the analytical tower (5) from the bottom of the absorption tower (4); Step 11: the mixed liquid enters the analytical tower (5) for separation, the separated propylene and propane mixture enters the distillation tower (6), and butyraldehyde is discharged from the bottom of the analytical tower (5); Step 12: After being processed in the distillation tower (6), propane is discharged from the bottom outlet, and propylene is discharged from the top of the distillation tower (6) into the propylene pipeline (10); Step 13: After being processed by the separator (7), the gas is compressed by the compressor (8) and enters the second reactor gas outlet pipeline (24), a part of the butyraldehyde enters the absorption tower (4), and a part is discharged from the bottom of the separator (7).

6. The method for synthesizing butyraldehyde by hydroformylation of propylene according to claim 5, characterized in that: In the step 1, the flow rate of propylene entering the first reactor (1) is controlled to be 10 m-15 m / s, the gas flow rate of the synthesis gas and hydrogen entering the first reactor (1) through the synthesis gas pipeline (9) and the first gas distributor (13) is controlled to be 20 m-50 m / s, and in the step 4, the flow rate of propylene, synthesis gas and hydrogen returning to the first reactor (1) through the feed port N3 is controlled to be 10 m-15 m / s.

7. The method for synthesizing butyraldehyde by hydroformylation of propylene according to claim 5, characterized in that: The angle between the fluid injection angle of the feed port N1 and the feed port N3 toward the first reaction kettle (1) and the horizontal line is set to 0°-45°, and the angle between the discharge port N2 and the feed port N3 and the horizontal plane is set to 90°-180°.

8. The method for synthesizing butyraldehyde by hydroformylation of propylene according to claim 5, characterized in that: The first cooler (12) is provided with a secondary line and a flow rate adjustment control is added, so that the temperature of the first reaction kettle (1) is controlled by adjusting the flow rate of the reaction liquid in the first cooler (12) and the flow rate of the reaction liquid in the secondary line of the first cooler (12).

9. The method for synthesizing butyraldehyde by hydroformylation of propylene according to claim 5, characterized in that: In step 5, the flow rate of the liquid entering the second reactor (2) from the feed port N5 is controlled to be 10m-15m / s, and in step 7, the flow rate of the liquid after heat exchange entering the second reactor (2) from the feed port N4 is controlled to be 10m-15m / s.

10. The method for synthesizing butyraldehyde by hydroformylation of propylene according to claim 5, characterized in that: The second cooler (22) is provided with a secondary line and a flow rate adjustment control is added, so that the temperature of the second reaction kettle (2) is controlled by adjusting the flow rate of the reaction liquid in the second cooler (22) and the flow rate of the reaction liquid in the secondary line of the second cooler (22).

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