A falling film reactor for uniform flow splitting in the production of hydroxyacetonitrile from hydrocyanic acid

Abstract

The invention belongs to the technical field of devices for generating new substances by gas-liquid contact reaction, and discloses a falling film reactor for uniformly splitting hydroxyacetonitrile by using hydrocyanic acid, comprising a tower body, on which an air inlet, a liquid inlet, an upper tube plate, a lower tube plate, an air outlet and a liquid outlet are arranged in sequence from top to bottom, a falling film tube is fixed between the upper tube plate and the lower tube plate, and a falling film head fixed by a fixing member is arranged in the falling film tube; an even number of liquid inlets are arranged, and the liquid inlets are evenly distributed along the circumference of the tower body, and two opposite liquid inlets are connected by a guide tube; a plurality of guide protrusions located near the liquid inlet are arranged on the upper tube plate, and the number of the liquid inlets is consistent with the number of the guide protrusions. The invention solves the problem that after a mixed liquid is introduced into an existing falling film reactor, the mixed liquid will flow down from the falling film tube closer to the liquid inlet, resulting in a "dry tube" in other falling film tubes, affecting the contact reaction between hydrocyanic acid and the mixed liquid, and resulting in low production efficiency of hydroxyacetonitrile.

Description

Technical Field

[0001] The invention belongs to the technical field of devices for generating new substances by utilizing gas-liquid contact reaction, and in particular relates to a falling film reactor for uniformly dividing hydroxyacetonitrile in manufacturing hydrocyanic acid. Background Art

[0002] Hydroxyacetonitrile, also known as glycolonitrile or formaldehyde cyanohydrin, is a colorless to light yellow liquid. Hydroxyacetonitrile is widely used in the industries of medicine, electroplating, mineral processing, pesticides, chemicals, dyes, surfactants, etc., and can also be used as an intermediate for the production of glycine, iminodiacetic acid (intermediate of glyphosate), malononitrile, indigo dye, polyglycolic acid, hydantoin, sodium ethylenediaminetetraacetate (EDTA), etc. The preparation method of hydroxyacetonitrile mainly includes acetonitrile oxidation method and hydrocyanic acid hydroxymethylation method, wherein the hydrocyanic acid hydroxymethylation method is to use formaldehyde and hydrocyanic acid to react under neutral to alkaline conditions to generate hydroxyacetonitrile, and an aqueous solution of sodium hydroxide or sodium cyanide is usually used as a catalyst. The specific operation is to mix the formaldehyde aqueous solution with the catalyst (sodium hydroxide or sodium cyanide) aqueous solution and add it into the falling film reactor, and then pass hydrocyanic acid gas into the falling film reactor, so that the hydrocyanic acid gas contacts and reacts with the mixed solution to generate hydroxyacetonitrile.

[0003] The commonly used falling film reactor includes a tower body, on which an air inlet, a liquid inlet, an air outlet and a liquid outlet are arranged in sequence from top to bottom, and a mounting plate, an upper tube plate and a lower tube plate are arranged in sequence from top to bottom in the tower body, and the liquid inlet is located between the mounting plate and the upper tube plate; the upper tube plate and the lower tube plate are provided with a plurality of vertical corresponding through holes, a falling film tube is fixed in the corresponding through holes, and a plurality of falling film heads are also provided on the mounting plate, and the bottom of the falling film head is inserted into the falling film tube. When in use, a mixed liquid is introduced into the tower body through the liquid inlet, and the mixed liquid flows on the upper tube plate. When the liquid level reaches the height of the falling film tube, it enters the falling film tube and flows downward; then hydrocyanic acid gas is introduced through the air inlet, and the hydrocyanic acid gas enters the falling film tube through the falling film head, contacts and reacts with the mixed liquid flowing along the inner wall of the falling film tube, thereby generating hydroxyacetonitrile.

[0004] However, the inventors found that in actual use, after the mixed liquid enters the tower body through the liquid inlet, it will flow down from the falling film tube closer to the liquid inlet, causing the other falling film tubes to become "dry pipes". The "dry pipe" will affect the contact reaction between the hydrocyanic acid gas and the mixed solution, and thus affect the production efficiency of hydroxyacetonitrile. Summary of the invention

[0005] The present invention aims to provide a falling film reactor with uniform flow diversion for producing hydroxyacetonitrile from hydrocyanic acid, so as to solve the problem that after a mixed liquid is introduced into the existing falling film reactor, the mixed liquid will flow down from the falling film tube closer to the liquid inlet, causing the other falling film tubes to become "dry", thus affecting the contact reaction between hydrocyanic acid and the mixed liquid and causing low production efficiency of hydroxyacetonitrile.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a falling film reactor for uniformly splitting hydroxyacetonitrile produced by producing hydrocyanic acid, comprising a tower body, on which an air inlet, a liquid inlet, an air outlet and a liquid outlet are sequentially arranged from top to bottom; an upper tube sheet and a lower tube sheet are further arranged between the liquid inlet and the air outlet on the tower body; the upper tube sheet and the lower tube sheet are both provided with through holes; a falling film tube is fixed between the through holes opposite to each other on the upper tube sheet and the lower tube sheet; a falling film head is inserted into the falling film tube, and a fixing piece fixed to the falling film tube is provided on the falling film head; an even number of liquid inlets are arranged, and the liquid inlets are uniformly distributed along the circumference of the tower body; two opposite liquid inlets are connected by a guide tube, and the guide tube is connected with a liquid inlet tube; a plurality of guide protrusions located near the liquid inlet are arranged on the upper tube sheet, and the number of the liquid inlets is consistent with the number of the guide protrusions.

[0007] The technical principle of this technical solution:

[0008] The mixed liquid is introduced through the liquid inlet. Since there are multiple liquid inlets and they are evenly distributed on the tower body, the mixed liquid can enter multiple parts of the tower body. After entering the tower body, the mixed liquid impacts the guide protrusion, so it is blocked and flows to both sides of the guide protrusion, so that it is evenly arranged along the circumference of the upper tube plate, and then flows into the falling film tube and forms a liquid film on the inner wall of the falling film tube. In addition, hydrogen cyanide gas is introduced into the tower body through the air inlet, so that part of the hydrogen cyanide gas is introduced into the falling film tube through the falling film head to contact and react with the liquid film, while part of the hydrogen cyanide gas directly contacts and reacts with the mixed liquid on the upper tube plate. The reacted liquid and the residual gas are guided to the bottom of the tower body through the falling film tube, and the produced product (reacted liquid) is discharged through the liquid outlet, and the residual gas is discharged through the air outlet.

[0009] Beneficial effects of this technical solution:

[0010] 1. This technical solution provides a guide protrusion at the liquid inlet, so that after the gas enters the tower body, it impacts the guide protrusion, is blocked by the guide protrusion, and flows to both sides of the guide protrusion, so that the mixed liquid is evenly distributed along the circumference of the upper tube plate, and then enters the falling film tube, reducing the probability of "dry tube" in the falling film tube;

[0011] 2. Using a guide pipe to connect the two liquid inlets can achieve the goal of connecting one liquid inlet component to complete the liquid inlet of the two liquid inlets, which can reduce the setting of pipes and liquid inlet components; at the same time, compared with all liquid inlet components being connected by one pipe, the liquid flowing out of each liquid inlet can have a certain flow rate, and after impacting the guide protrusion, it can quickly spread to both sides, so as to evenly cover the upper tube plate along the circumferential direction;

[0012] 3. Compared with the prior art, this technical solution does not use a mounting plate to fix the falling film head, but directly sets a fixing piece on the falling film head to achieve fixation, which can greatly shorten the installation time; and the gas will not be hindered by the mounting plate after entering the tower body. When entering the falling film head, it can also directly contact and react with the liquid on the upper tube plate, thereby improving the reaction effect;

[0013] Through actual tests by the inventors, it was found that when installing the falling film head of a traditional falling film reactor, it takes 3-4 days for each installation because the falling film head is not easy to align with the falling film tube. However, through improvements, the installation can now be completed within 1 day, greatly shortening the installation time and reducing the time cost of hydroxyacetonitrile production.

[0014] Furthermore, an annular distribution plate is fixed on the upper tube plate, the flow guide protrusions are all located on the outer circle of the distribution plate, and the falling film tubes are located on the inner circle of the distribution plate.

[0015] Beneficial effect: The annular distribution plate can make the mixed liquid overflow after the liquid level between the distribution plate and the inner wall of the tower body reaches a certain height, and flow and distribute on the upper tube plate, thereby improving the uniformity of the distribution of the mixed liquid on the upper tube plate.

[0016] Furthermore, a plurality of sawtooth grooves are provided on the top of the distribution plate.

[0017] Beneficial effect: the mixed liquid can overflow within a height range, and the setting of the sawtooth groove can make the liquid overflow in a slow trickle manner, with a good overflow effect.

[0018] Furthermore, it also includes a baffle ring located at the inner circle of the distribution plate, a flow channel is formed between the bottom of the baffle ring and the upper tube plate, a connecting rod is fixed between the outer circle of the baffle ring and the inner circle of the distribution plate, and the baffle ring wraps all the falling film tubes.

[0019] Beneficial effect: After the mixed liquid between the distribution plate and the tower body overflows, it will enter between the baffle ring and the distribution plate, flow downward, and then diffuse and spread to the middle of the upper tube plate through the flow channel. It can make the liquid spread and diffuse horizontally on the upper tube plate, making it easier for the liquid to flow toward the middle of the upper tube plate and achieve uniform distribution.

[0020] Furthermore, the guide protrusion is arc-shaped, and the inner arc surface of the guide protrusion faces the distribution plate.

[0021] Beneficial effect: The arc-shaped guide protrusion has a very good effect of guiding the flow to both sides, thereby improving the uniform distribution of the mixed liquid along the circumference of the upper tube plate.

[0022] Furthermore, the fixing member comprises a plurality of fixing blocks distributed along the circumference of the falling film head, the free ends of the fixing blocks are bent downward, and the bent portions of the fixing blocks are clamped on the falling film.

[0023] Beneficial effect: the falling film head and the falling film tube can be fixed by clamping the bent part of the fixing block on the falling film tube. Even if there is no mounting plate, the falling film head can be fixed; and the setting is very convenient.

[0024] Furthermore, the bottom of the falling film head is in a truncated cone shape, and a gap is left between the bottom end of the falling film head and the inner wall of the falling film tube.

[0025] Beneficial effect: The bottom end of the falling film head is set in a truncated cone shape, which can guide the gas in the falling film head, so that the gas flows toward the inner wall of the falling film tube when it is guided from the falling film head to the falling film tube, completing the contact reaction between the gas and the liquid film. In addition, the bottom end of the falling film head can also limit the flow of the liquid, so that the liquid always forms a liquid film along the inner wall of the falling film head, and even if the liquid flow rate and flow rate on the upper tube plate are large, it will not affect the liquid from forming a liquid film in the falling film tube.

[0026] Furthermore, flow guide channels are evenly distributed in the circumferential direction on the upper portion of the upper tube plate, and the flow guide channels are arranged along the flow channel toward the middle portion of the upper tube plate.

[0027] Beneficial effect: The guide channel can guide the mixed liquid, so that the mixed liquid quickly flows to the middle of the upper tube plate, and completes the uniform distribution of the mixed liquid on the upper tube plate, thereby reducing the occurrence of dry pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0029] Figure 2 for Figure 1 Top view of the middle and upper tube sheet;

[0030] Figure 3 for Figure 1 A magnified view of part A;

[0031] Figure 4 This is a schematic diagram of the structure of Embodiment 2 of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of Example 3 of the present invention. DETAILED DESCRIPTION

[0033] The following is further described in detail through specific implementation methods:

[0034] The reference numerals in the drawings of the specification include: tower body 1, air inlet 11, liquid inlet 12, liquid guide pipe 121, air outlet 13, liquid outlet 14, upper tube plate 2, guide protrusion 21, distribution plate 22, guide hole 221, baffle plate 23, connecting rod 24, guide channel 25, lower tube plate 3, falling film tube 4, falling film head 5, fixing block 51, liquid storage tank 6, rotating shaft 61, rotating impeller 611, driving gear 612, second driving bevel gear 613, liquid outlet pipe 62, rotating shaft 7, driven gear 71, first driving bevel gear 72, mounting block 8, driving shaft 81, dispersion blade 82, first driven bevel gear 83, separation tube 9, separation shaft 91, separation blade 911, second driven bevel gear 912.

[0035] Embodiment 1:

[0036] A falling film reactor for uniformly splitting hydroxyacetonitrile produced by producing hydrocyanic acid, substantially as shown in the attached Figure 1 As shown, the tower body 1 includes an air inlet 11, a liquid inlet 12, an air outlet 13 and a liquid outlet 14, which are arranged on the tower body 1 from top to bottom. The air inlet 11 is arranged at the top of the tower body 1, and the liquid outlet 14 is arranged at the bottom of the tower body 1. The liquid inlet 12 is arranged at the upper part of the tower body 1, and there are an even number of liquid inlets 12. In this embodiment, there are 8 liquid inlets 12, and the 8 liquid inlets 12 are evenly distributed along the axial direction of the tower body 1. The two opposite liquid inlets 12 are connected by a liquid guide tube 121, and the liquid guide tube 121 is connected to a liquid inlet component. In this embodiment, the liquid inlet component is a liquid pump. The air outlet 13 is arranged on the right side of the lower part of the tower body 1.

[0037] An upper tube sheet 2 and a lower tube sheet 3 are also provided in the tower body 1 between the liquid inlet 12 and the gas outlet 13. The upper tube sheet 2 is provided with a plurality of through holes. The number and diameter of the through holes and the diameter of the tower body 1 are set according to actual needs. These data will not affect the specific use of the device, so the specific data are not disclosed here. The lower tube sheet 3 is also provided with a plurality of through holes. The through holes on the upper tube sheet 2 and the through holes on the lower tube sheet 3 are equal in number, and the through holes on the upper tube sheet 2 and the through holes on the lower tube sheet 3 correspond one to one. Falling film tubes 4 are provided in the corresponding through holes on the upper tube sheet 2 and the lower tube sheet 3. The upper part of the falling film tube 4 is sealed and fixed to the through hole on the upper tube sheet 2, and the lower part of the falling film tube 4 is sealed and fixed to the through hole on the lower tube sheet 3.

[0038] Combination Figure 2 , Figure 3 As shown, the upper surface of the upper tube plate 2 is evenly distributed with 8 guide protrusions 21 along the circumferential direction, and each guide protrusion 21 corresponds to a liquid inlet 12, that is, the liquid entering from the liquid inlet 12 will impact on the guide protrusion 21. The guide protrusion 21 is arc-shaped, and the inner arc surface of the guide protrusion 21 faces the middle of the upper tube plate 2.

[0039] An annular distribution plate 22 is welded to the inner ring of the eight flow guide protrusions 21 on the upper tube plate 2. The top of the distribution plate 22 is serrated. The outer ring of the distribution plate 22 is in contact with the inner ring of the eight flow guide protrusions 21. The distribution plate 22 wraps all the falling film tubes 4. A plurality of flow guide holes 221 are evenly distributed on the bottom of the distribution plate 22. A baffle ring located on the inner ring of the distribution plate 22 is also included. The baffle ring includes all the falling film tubes 4. The baffle ring and the distribution plate 22 are coaxially arranged, and there is a gap between the baffle ring and the distribution plate 22. A flow channel is formed between the bottom of the baffle ring and the upper surface of the upper tube plate 2. The baffle ring and the distribution plate 22 are fixed by a connecting rod 24, that is, one end of the connecting rod 24 is welded to the inner wall of the distribution plate 22, and the other end is welded to the outer ring of the baffle ring.

[0040] There are multiple flow guide channels 25 evenly distributed on the upper tube plate 2 at the inner circle of the baffle ring. In this embodiment, there are 8 flow guide channels 25, and the 8 flow guide channels 25 are all arranged from the baffle ring to the middle of the upper tube plate 2.

[0041] A falling film head 5 is provided in each of the falling film tubes 4, and a fixing part is provided on each of the falling film heads 5. The fixing part includes a plurality of fixing blocks 51 uniformly arranged along the circumference of the falling film head 5. In this embodiment, each fixing part includes three fixing blocks 51. One end of the fixing block 51 is welded to the outer wall of the falling film head 5, and the other end of the fixing block 51 is bent downward by 90°, and the fixing block 51 can be inserted into the falling film tube 4. The specific configuration of the falling film head 5 in the falling film tube 4 is that the falling film head 5 is inserted into the falling film tube 4. During the insertion of the falling film head 5, the bent part of the fixing block 51 is close to the outer wall of the falling film tube 4 and slides downward, so that the fixing part is inserted into the falling film tube 4, and the falling film head 5 is fixed. And the three fixing blocks 51 of each fixing part are evenly distributed on the falling film head 5, so when the falling film head 5 is inserted into the falling film tube 4, the three fixing blocks 51 are in contact with the inner wall of the falling film head 5, the falling film head 5 is positioned, and the falling film head 5 and the falling film tube 4 are aligned. The bottom of the falling film head 5 is in a truncated cone shape, and a gap is left between the bottom end of the falling film head 5 and the inner wall of the falling film tube 4.

[0042] The specific implementation process is as follows:

[0043] When in use, liquid (mixed solution of formaldehyde aqueous solution and catalyst) is introduced into the tower body 1 through the liquid inlet 12. When the liquid enters the tower body 1 from the liquid inlet 12, it impacts the guide protrusion 21, and flows to both sides of the guide protrusion 21 after being diverted and guided by the guide protrusion 21, so that the liquid is evenly distributed along the circumference. As the liquid is continuously introduced and the liquid is blocked by the distribution plate 22, the liquid level gradually rises. When the liquid level rises to the top of the distribution plate 22, the liquid leaves the gap between the distribution plate 22 and the baffle ring, and flows horizontally through the flow channel. The liquid between the distribution plate 22 and the inner wall of the tower body 1 will also flow through the guide hole 221, generating a horizontal impact force, thereby driving the liquid to flow toward the middle of the upper tube plate 2. Combined with the flow guidance of the flow guide channel 25, the liquid spreads to the middle of the upper tube sheet 2, and the liquid level gradually rises until the liquid level is flush with the falling film tube 4. The liquid enters the falling film tube 4 and flows along the inner wall of the falling film tube 4 to form a liquid film.

[0044] At the same time, hydrocyanic acid gas is introduced into the tower body 1 through the air inlet 11. After the hydrocyanic acid gas enters the tower body 1, it first contacts and reacts with the liquid on the upper tube plate 2. As the gas is continuously added, the pressure above the upper tube plate 2 in the tower body 1 gradually increases. Therefore, the gas gradually enters the falling film head 5, flows downward along the falling film head 5 and enters the falling film tube 4, and then is guided through the truncated cone-shaped bottom of the falling film head 5, so that the hydrocyanic acid gas contacts and reacts with the liquid film on the inner wall of the falling film tube 4.

[0045] The liquid and hydrocyanic acid gas entering the falling film tube 4 flow downward along the falling film tube 4 and continue to contact and react until the reacted liquid and gas flow out of the falling film tube 4. After the liquid and gas flow out of the falling film tube 4, they accumulate between the lower tube plate 3 and the falling film tube 4 at the bottom, so that the reacted liquid is discharged from the liquid outlet 14 and the reacted gas is discharged from the gas outlet 13.

[0046] In this process, when the liquid inlet speed is fast, the liquid level rises fast, and more liquid enters the falling film tube 4, so the liquid is not easy to flow along the inner wall of the falling film tube 4. When the liquid passes through the bottom of the falling film head 5, it can be guided by the truncated cone-shaped falling film head 5, so that the liquid flows along the inner wall of the falling film tube 4 to form a liquid film, thereby improving the effect of the contact reaction between the liquid and the gas.

[0047] Embodiment 2:

[0048] The difference between Example 2 and Example 1 is that Figure 4As shown, in this embodiment, a liquid storage tank 6 is also provided, and a mounting hole is provided on the top of the liquid storage tank 6, and the bottom of the tower body 1 is inserted into the mounting hole, and the bottom of the tower body 1 is welded to the mounting hole. A liquid outlet pipe 62 is connected to the lower part of the left side wall of the liquid storage tank 6, and a rotating shaft 61 is rotatably connected to the left side wall of the liquid storage tank 6. The left end of the rotating shaft 61 passes through the left side wall of the liquid storage tank 6, and a rotating impeller 611 is fixed to the rotating shaft 61 below the liquid outlet 14.

[0049] The left side of the bottom of the tower body 1 is rotatably connected with a rotating shaft 7, and the left end of the rotating shaft 7 passes through the left side wall of the tower body 1; a driving gear 612 is coaxially fixed to one end of the rotating shaft 61 located outside the liquid storage tank 6, and a driven gear 71 meshing with the driving gear 612 is coaxially fixed to one end of the rotating shaft 7 located outside the tower body 1.

[0050] A mounting block 8 is provided below the lower tube plate 3 in the tower body 1, and also includes a drive shaft 81 that penetrates the mounting block 8 and is vertically arranged. The drive shaft 81 is rotatably connected to the mounting block 8, and a dispersion blade 82 is fixed to one end of the drive shaft 81 located above the mounting block 8. A first active bevel gear 72 is fixed to one end of the rotating shaft 7 located in the tower body 1, and a first driven bevel gear 83 that meshes with the first active bevel gear 72 is coaxially fixed to the bottom end of the drive shaft 81.

[0051] The specific implementation process is as follows:

[0052] After the liquid and gas are led out from the falling film tube 4, the liquid is discharged through the liquid outlet 14, and the gas is discharged through the gas outlet 13. Since there are multiple falling film tubes 4, the amount of liquid discharged from the falling film tube 4 is relatively large, so that the liquid is discharged from the gas outlet 13 and impacts the rotating impeller 611, so that the rotating impeller 611 drives the rotating shaft 61 to rotate, and the rotating shaft 7 drives the driving bevel gear to rotate through the transmission of the driving gear 612 and the driven gear 71. Through the transmission of the driven bevel gear, the driving shaft 81 drives the dispersion blades 82 to rotate. When the dispersion blades 82 rotate, the liquid flowing out of the falling film tube 4 is dispersed, so that the liquid and the gas are contacted and reacted again, thereby improving the reaction effect.

[0053] Embodiment 3:

[0054] The difference between Example 3 and Example 2 is that Figure 5As shown, in this embodiment, a separation part is also provided, and the separation part includes an L-shaped separation tube 9, and the separation tube 9 includes a transverse part connected to the air outlet 13 and a vertical part connected to the transverse part. The transverse part is inclined upward from left to right, and the inclination angle is 10-15°, and 10° is preferred in this embodiment; the opening of the vertical part faces upward. A separation shaft 91 is coaxially arranged in the vertical part, and the bottom of the separation shaft 91 passes through the transverse part and extends downward, and the separation shaft 91 is rotatably connected to the transverse part. Separation blades 911 are distributed circumferentially on the upper part of the separation shaft 91 located in the vertical part, and the separation blades 911 are inclined.

[0055] The right end of the rotating shaft 61 penetrates the right wall of the liquid storage tank 6 and is rotatably connected to the right wall of the liquid storage tank 6. A second driving bevel gear 613 is fixed to the right end of the rotating shaft 61, and a second driven bevel gear 912 meshing with the second driving bevel gear 613 is fixed to the bottom of the separation shaft 91.

[0056] The specific implementation process is as follows:

[0057] Since the dispersing blades 82 disperse the gas and keep in contact with the gas, the discharged gas will be mixed with liquid. In the process of liquid extraction, when the rotating shaft 61 rotates, the second active bevel gear 613 rotates, the separation shaft 91 rotates, and then the separation blades 911 drive the gas to rotate. In this process, due to the different flow rates of gas and liquid, the gas flows upward quickly, while the liquid is separated and flows downward along the separation blades 911, falls into the transverse part, and then flows to the bottom of the tower body 1 and is discharged from the liquid outlet 14.

[0058] For those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention. These will not affect the effect of the implementation of this patent and the practicality of the patent.

Claims

1. A falling film reactor for producing hydroxyacetonitrile with hydrocyanic acid and uniform flow distribution, comprising a tower body, on which an air inlet, a liquid inlet, an air outlet and a liquid outlet are arranged in order from top to bottom, an upper tube sheet and a lower tube sheet are arranged between the liquid inlet and the air outlet in the tower body, through holes are arranged on the upper tube sheet and the lower tube sheet, a falling film tube is fixed between the through holes facing each other on the upper tube sheet and the lower tube sheet, and a falling film head is inserted into the falling film tube, characterized in that: The falling film head is provided with a fixing piece fixed to the falling film tube; an even number of liquid inlets are provided, and the liquid inlets are evenly distributed along the circumference of the tower body, and two opposite liquid inlets are connected through a guide pipe, and the guide pipe is connected to the liquid inlet pipe; a plurality of guide protrusions located near the liquid inlets are provided on the upper tube plate, and the number of the liquid inlets is consistent with the number of the guide protrusions; An annular distribution plate is fixed on the upper tube plate, the flow guide protrusions are all located on the outer circle of the distribution plate, and the falling film tubes are located on the inner circle of the distribution plate; A liquid storage tank is fixed at the bottom of the tower body, and a rotating shaft is rotatably connected to the side wall of the liquid storage tank, a driving gear is fixed to one end of the rotating shaft, and a rotating impeller is fixed to the other end, and the rotating impeller is located below the liquid outlet; a rotating shaft is rotatably connected to the bottom of the tower body, and a driven gear meshing with the driving gear is coaxially fixed to the transmission shaft; a driving shaft is rotatably arranged on the tower body, a dispersion blade is fixed to one end of the driving shaft, a first driving bevel gear is fixed to one end of the rotating shaft, and a first driven bevel gear meshing with the first driving bevel gear is coaxially fixed to the free end of the driving shaft.

2. A falling film reactor for uniform flow splitting of hydroxyacetonitrile produced by hydrocyanic acid according to claim 1, characterized in that: A plurality of sawtooth grooves are arranged on the top of the distribution plate.

3. A falling film reactor for uniform flow splitting of hydroxyacetonitrile produced by hydrocyanic acid according to claim 2, characterized in that: It also includes a baffle ring located at the inner circle of the distribution plate, a flow channel is formed between the bottom of the baffle ring and the upper tube plate, a connecting rod is fixed between the outer circle of the baffle ring and the inner circle of the distribution plate, and the baffle ring wraps all the falling film tubes.

4. A falling film reactor for uniformly splitting hydroxyacetonitrile produced by producing hydrocyanic acid according to any one of claims 1 to 3, characterized in that: The guide protrusion is arc-shaped, and the inner arc surface of the guide protrusion faces the distribution plate.

5. A falling film reactor for uniform flow splitting of hydroxyacetonitrile produced by producing hydrocyanic acid according to claim 4, characterized in that: The fixing member comprises a plurality of fixing blocks distributed along the circumference of the falling film head, the free ends of the fixing blocks are bent downward, and the bent parts of the fixing blocks are clamped on the falling film.

6. A falling film reactor for uniform flow splitting of hydroxyacetonitrile produced by producing hydrocyanic acid according to claim 5, characterized in that: The bottom of the falling film head is in a truncated cone shape, and a gap is left between the bottom end of the falling film head and the inner wall of the falling film tube.

7. A falling film reactor for uniform flow splitting of hydroxyacetonitrile produced by producing hydrocyanic acid according to claim 6, characterized in that: The upper tube plate has flow guide channels evenly distributed in the circumferential direction on the upper surface thereof, and the flow guide channels are arranged along the flow passage toward the middle of the upper tube plate.

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