An acetone cyanohydrin acylation reactor and control system thereof

Abstract

The present application relates to chemical equipment and control technology field, provide a kind of acetone cyanohydrin acylation reactor, including shell, agitator, cooling system, acetone cyanohydrin distributor;Agitator includes motor, stirring shaft, paddle, paddle includes radial paddle, axial paddle, dispersion paddle, the blade of dispersion paddle is specific three-section type that main body is inclined upward, can simultaneously generate radial flow and axial flow;Acetone cyanohydrin distributor is circular ring, and two rows of openings are arranged along circumference on the lower side, and two rows of holes are staggered, so that acetone cyanohydrin is distributed in reactor in larger cross section;Cooling system includes multiple groups of heat exchange water pipes, improves heat exchange amount and heat exchange efficiency;Agitator, cooling system, acetone cyanohydrin distributor synergistic effect, so that acetone cyanohydrin and sulfuric acid in reaction kettle can be quickly and uniformly mixed, heat is removed in time, avoid local overheating, effectively reduce the probability of side reaction occurrence.The present application also discloses the control system of the above-mentioned acetone cyanohydrin acylation reactor.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment and control technology, specifically to an acetone cyanohydrin acylation reactor and its control system. Background Technology

[0002] In the acetone cyanohydrin process for producing methyl methacrylate (MMA), the intermediate reaction involving the acylation of acetone cyanohydrin with concentrated sulfuric acid to form α-formamidoisopropyl hydrogen sulfate is a key step in MMA production. The reaction equation is as follows:

[0003]

[0004] This reaction is highly exothermic, fast-paced, and requires strict temperature control. If the heat of reaction cannot be removed in time, overheating will occur, leading to a large number of side reactions. This will not only reduce the yield, but some byproducts will also react further in downstream processes, causing blockages and preventing the equipment from operating normally.

[0005] Patent CN210613689U discloses an acylation reactor with an internal heat exchange tube bundle, a multi-stage agitator, and a multi-stage acetone cyanohydrin inlet. The reactor features multi-point temperature measurement to monitor temperatures in different regions. The reactor's agitator blades include both stirring blades and scrapers, which are alternately distributed. The acetone cyanohydrin inlet is located within the same horizontal cross-section of the scrapers and on the outer side of the blades. By utilizing the scrapers to rapidly disperse the acetone cyanohydrin feed, localized temperature runaway caused by excessively high local acetone cyanohydrin concentrations is avoided, reducing temperature inhomogeneity and the incidence of side reactions within the reactor. However, the scrapers are radial blades, and their dispersion of acetone cyanohydrin is mainly concentrated within the horizontal cross-section, contributing little to axial dispersion. The lowest layer of scrapers, in particular, cannot achieve rapid mixing of acetone cyanohydrin and sulfuric acid. Currently, most domestic acetone cyanohydrin process plants use the aforementioned acylation reactors, which have many acylation side reactions, low product yields, and acylation byproducts that continue to react in downstream esterification reaction units, causing polymer accumulation, blockage of the reaction system, and inability to operate continuously for long periods.

[0006] Therefore, it is necessary to develop an acylation device that can reduce the occurrence rate of side reactions in acetone cyanohydrin acylation and improve the reaction yield. Summary of the Invention

[0007] The purpose of this invention is to provide an acylation apparatus that can reduce the occurrence rate of side reactions in acetone cyanohydrin acylation and improve the reaction yield.

[0008] To achieve the above objectives, the present invention provides an acetone cyanohydrin acylation reactor, comprising a shell, a stirrer, a cooling system, and an acetone cyanohydrin distributor. The shell is provided with an acetone cyanohydrin inlet, a sulfuric acid inlet, and a liquid outlet. The acetone cyanohydrin inlet is connected to the acetone cyanohydrin distributor. The stirrer includes a motor, a stirring shaft, and blades disposed on the stirring shaft. The blades include axial blades, radial blades, and dispersing blades.

[0009] Preferably, the blades include at least two groups, wherein the lowermost group includes an axial blade and a dispersion blade located below the axial blade, and the remaining groups include an axial blade and a radial blade.

[0010] Preferably, the dispersion blade comprises multiple blades, which are three-sectioned: a horizontal section, a main section, and a bending section. The length of the main section is 5 / 6 to 4 / 5 of the total blade length, and the main section is inclined upward at an angle of 5° to 10°. The length of the horizontal section is 1 / 6 to 1 / 5 of the total blade length, and the length of the bending section is 1 / 6 to 1 / 5 of the total blade length. The angle between the bending section and the main section is 10° to 20°.

[0011] Preferably, the distance between two adjacent blades is 1 to 2 times the blade diameter, and the uppermost blade is located below the liquid outlet, with a distance between it and the liquid outlet of 1.5 to 2 times the blade diameter.

[0012] Preferably, the diameter of the impeller is 1 / 4 to 1 / 3 of the diameter of the reactor.

[0013] The acetone cyanohydrin distributor provided by the present invention is annular, with two rows of holes arranged alternately along the circumference of the bottom surface.

[0014] Preferably, the included angle between the two rows of holes is 90° to 130°, the diameter of the holes is 8mm to 15mm, and the center-to-center distance between two adjacent holes is 2 to 3 times the diameter of the holes.

[0015] Preferably, the acetone cyanohydrin distributor is located below the blade, the distance between the top of the acetone cyanohydrin distributor and the bottom of the blade is 20mm to 80mm, and the inner diameter of the acetone cyanohydrin distributor is 0.8 to 1.2 times the diameter of the blade.

[0016] Preferably, the acetone cyanohydrin distributor comprises at least two, respectively disposed below the radial blade and the dispersion blade.

[0017] The cooling system provided by the present invention includes multiple sets of hot water exchange pipes. The hot water exchange pipes are U-shaped and include multiple sets. Adjacent hot water exchange pipes are arranged in an equilateral triangle, and the center-to-center distance is 1 to 2 times the diameter of the hot water exchange pipe.

[0018] Preferably, the hot water replacement pipes include 3 to 8 sets, and the diameter of the hot water replacement pipes is 10mm to 25mm.

[0019] Preferably, the distance between the inner heat exchange pipe and the outer edge of the impeller in the cooling system is 20mm to 60mm, and the distance between the outer heat exchange pipe and the inner wall of the reactor is 50mm to 100mm.

[0020] Preferably, the cooling system further includes a cooling jacket disposed outside the housing.

[0021] Preferably, the length-to-diameter ratio of the reactor is 5 to 10.

[0022] The present invention also provides a control system for an acetone cyanohydrin acylation reactor, including a temperature detection controller, a temperature anomaly controller, an acetone cyanohydrin feed control unit, and a cooling medium flow rate regulation unit;

[0023] The temperature detection controller is connected to the cooling medium flow regulation unit and the temperature abnormality controller respectively. The temperature abnormality controller is connected to the acetone cyanohydrin feed control unit.

[0024] The temperature detection controller includes multiple temperature sensors arranged in different areas of the reactor to detect the temperature in different areas. When the temperature difference between different areas is greater than 0 and less than the set allowable range, the temperature detection controller feeds back the highest temperature to the cooling medium flow regulation unit, which increases the cooling medium flow rate. When the temperature difference between different areas exceeds the set allowable range, the temperature detection controller feeds back the highest temperature to the temperature anomaly controller. The acetone cyanohydrin feed control unit includes multiple units, corresponding to the temperature sensors. The temperature anomaly controller controls the acetone cyanohydrin feed control unit based on the highest temperature fed back by the temperature detection controller, which reduces the acetone cyanohydrin feed rate in the area corresponding to the highest temperature. After the temperature returns to the set allowable range, it automatically switches back to the temperature detection controller control mode.

[0025] Preferably, it also includes a sulfuric acid feed control unit, which is connected to an acetone cyanohydrin feed control unit. The sulfuric acid feed rate is adjusted according to the total acetone cyanohydrin feed rate, and the ratio of the total acetone cyanohydrin feed rate to the sulfuric acid feed rate is controlled within a set range.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The agitator of the reactor of the present invention includes radial blades, axial blades and dispersion blades. Conventional blades can only produce one main flow pattern, namely axial flow or radial flow. However, the blades of the present invention achieve complex mixing flow pattern control through a specific three-section structure. At the same time, they can quickly disperse and mix acetone cyanohydrin across the entire reactor cross section, while turning up the feed sulfuric acid at the bottom of the reactor to dilute the acetone cyanohydrin. This makes it easier to remove the exothermic reaction, and the temperature rise of the material is more uniform. It can also avoid the formation of a fluid mixing dead zone in the reactor bottom and increase the effective volume of the reactor.

[0028] (2) The acetone cyanohydrin distributor of the reactor of the present invention enables acetone cyanohydrin to be distributed in the reactor over a larger cross-sectional area. The acetone cyanohydrin distributor is set below each set of impellers, so that the acetone cyanohydrin is immediately dispersed by the impellers after flowing out, and quickly and evenly mixed with sulfuric acid, avoiding local overheating and effectively reducing the probability of side reactions.

[0029] (3) The cooling system of the reactor of the present invention has a safe and reasonable structure, which can increase the heat exchange and heat exchange efficiency and meet the heat exchange requirements of the acetone cyanohydrin acylation reaction.

[0030] (4) The control system of this invention can realize temperature control and reaction feed control. By coordinating the cooling medium flow control and the acetone cyanohydrin feed control at each stage, the temperature of each feed zone is precisely controlled and adjusted, thereby achieving precise temperature control in each zone of the reactor. The reaction feed control includes the distribution control between the multi-stage acetone cyanohydrin feed and the ratio (reaction ratio) of the total acetone cyanohydrin feed to the sulfuric acid feed, which is precisely controlled according to the settings. Attached Figure Description

[0031] To more fully understand this disclosure, reference can be made to the following description of exemplary embodiments taken in conjunction with the accompanying drawings.

[0032] In the picture:

[0033] Figure 1 A longitudinal cross-sectional view of the acetone cyanohydrin acylation reactor of the present invention.

[0034] Figure 2 A schematic diagram of the dispersion stirring blade of the present invention.

[0035] Figure 3A A bottom view of the acetone cyanohydrin distributor of the present invention.

[0036] Figure 3B A cross-sectional view of the acetone cyanohydrin distributor ring of the present invention.

[0037] Figure 4A The location diagram of the hot water exchange pipe in the acetone cyanohydrin acylation reactor of the present invention.

[0038] Figure 4B A schematic diagram of the hot water exchange pipe of the present invention.

[0039] Figure 5 A schematic diagram of the control system of the acetone cyanohydrin acylation reactor of the present invention.

[0040] Figure 6 A schematic diagram of the acetone cyanohydrin acylation reactor and control system of the present invention.

[0041] List of reference numerals: 1-Shell; 2-Agitator; 201-Motor; 202-Agitator shaft; 2031, 2032, 2033, 2034-Axial blades; 2041, 2042, 2043-Radial blades; 205-Dispersion blades; 205a-Horizontal section, 205b-Main body section, 205c-Bent section; 3-Acetone cyanohydrin distributor; 4-Acetone cyanohydrin inlet; 5-Sulfuric acid inlet; 6-Gas outlet; 7-Liquid outlet; 801-Cooling jacket; 802-Cooling medium inlet; 803-Cooling medium outlet; 901-Hot water pipe; 902- Cooling medium inlet; 903-Cooling medium outlet; 10-Temperature detection controller; 11-Acetone cyanohydrin feed control unit; 1101-Acetone cyanohydrin controller; 1102-Acetone cyanohydrin feed regulating valve; 12-Sulfuric acid feed control unit; 1201-Sulfuric acid feed controller; 1202-Sulfuric acid feed regulating valve; 13-Temperature anomaly controller; 14-Cooling medium flow regulating unit; 14a-Hot water exchanger pipe cooling medium regulating valve; 14b-Cooling jacket cooling medium regulating valve; a1, a2, a3, a4-Acetone cyanohydrin feed pipelines; T1, T2, T3, T4-Temperature sensors. Detailed Implementation

[0042] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0043] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0044] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions; "inner" and "outer" generally refer to the interior or exterior of the cavity relative to the inner chamber or the radial interior or exterior relative to the center of the circle.

[0045] like Figure 1~3. This embodiment provides an acetone cyanohydrin acylation reactor, including a shell 1, a stirrer 2 located in the center of the shell, a cooling system, and an acetone cyanohydrin distributor 3. Multiple acetone cyanohydrin inlets 4, corresponding to the acetone cyanohydrin distributor 3, are arranged vertically on the side of the shell. A gas outlet 6 and a liquid outlet 7 are provided at the top of the shell, and a sulfuric acid inlet 5 is provided at the bottom of the shell. The length-to-diameter ratio of the reactor is 5-10.

[0046] The agitator 2 in the reactor includes a motor 201, a stirring shaft 202, and multiple blades mounted on the stirring shaft. In this embodiment, the blades include four sets, of which three sets each include an axial blade 2031, 2032, 3033 and a radial blade 2041, 2042, 2043. The axial blades are located above the radial blades, and the bottom set of blades includes an axial blade 2034 and a dispersing blade 205.

[0047] The axial blades lift the material below the blades upwards through the outer side of the blades and form a downward circulation on the inner side of the blades, creating back mixing and promoting mixing between materials. At the same time, it increases the turbulence of the material at the outer wall of the heat exchange pipe, reduces thermal resistance, and improves the heat exchange system and heat transfer efficiency.

[0048] The radial blades diffuse the material from the inside to the outside of the blades, and change the flow direction on the inner wall of the reactor or the outer wall of the heat exchange pipe, turning it back to the blades. This rapidly disperses acetone cyanohydrin throughout the entire reactor cross section, and the concentration of acetone cyanohydrin is quickly diluted under the stirring action of two adjacent axial blades.

[0049] The dispersion blade 205 is located below the axial blade 2034. In this embodiment, the dispersion blade includes three blades, such as... Figure 2 As shown, the blades are three-sectioned: horizontal section 205a, main section 205b, and bent section 205c. The horizontal section generates radial flow, dispersing acetone cyanohydrin within the horizontal cross-section of the reactor. The length of the horizontal section is 1 / 5 to 1 / 4 of the total blade length. If it is too short, the dispersion effect on acetone cyanohydrin will be insignificant; if it is too long, it will weaken the effect of agitating the concentrated sulfuric acid at the bottom of the reactor. The main section generates both radial and axial flow. The length of the main section is 5 / 6 to 4 / 5 of the total blade length. The main section is inclined upwards at an angle of 5°-10°. If the angle is too small, it will not be able to agitate the concentrated sulfuric acid at the bottom of the reactor; if the angle is too large, it will weaken the dispersion effect on acetone cyanohydrin. The bending section is 1 / 6 to 1 / 5 of the total blade length, and the angle between the bending section and the main section is 10° to 20°. The function of the bending section is to control the axial flow within a small axial range near the dispersing blade (with the mixing center as the center, the vertical mixing height is about the length of the main section), avoiding axial flow in a larger area, which saves energy and enables rapid dispersion and mixing of acetone cyanohydrin and concentrated sulfuric acid.

[0050] The spacing between two adjacent layers of blades is 1 to 2 times the blade diameter. The uppermost blade, axial blade 2031, is located below the liquid outlet 7, and the spacing between it and the liquid outlet 7 is 1.5 to 2 times the blade diameter. The blade diameter is 1 / 4 to 1 / 3 of the reactor diameter. Therefore, the structure of the stirrer of this invention ensures rapid and uniform mixing of the reaction materials and an effective heat exchange rate between the reaction mixture and the cooling system, avoiding local overheating and effectively reducing the probability of side reactions.

[0051] The acetone cyanohydrin distributor 3 in the reactor is annular, with an inner diameter 0.8 to 1.2 times the diameter of the impeller. For example... Figure 3A As shown, the acetone cyanohydrin distributor has two rows of holes distributed circumferentially on both the inner and outer diameter sides of its bottom surface. These holes are staggered, with a diameter of 8mm to 15mm, and the center-to-center distance between adjacent holes is 2 to 3 times the hole diameter. Figure 3B As shown, the included angle between the two rows of holes in the acetone cyanohydrin distributor is 90° to 130°. Setting the angle within this range allows the acetone cyanohydrin to be dispersed over a larger horizontal cross-section. Then, through a radial flow stirring impeller, it achieves uniform mixing with the rising stream in a counter-current flow. If the angle is too small, the dispersion effect is poor; if the angle is too large, it easily leads to high concentrations of acetone cyanohydrin in the center and on the side walls, reducing the mixing effect. In this embodiment, four acetone cyanohydrin distributors are included, each positioned below a set of impeller blades. The distance between the top of each acetone cyanohydrin distributor and the bottom of the impeller blade is 20mm to 80mm. The acetone cyanohydrin distributor and the stirrer of this invention work synergistically, ensuring that after the acetone cyanohydrin flows out of the distributor, it is immediately further dispersed by the impeller blades of the stirrer, resulting in uniform mixing with the sulfuric acid in the reactor.

[0052] To better control the heat generated by the exothermic reaction, the reactor in this embodiment includes 3 to 8 sets of hot water exchange pipes 901 disposed in an annular region between the reactor inner wall and the stirrer. The inlet and outlet of the hot water exchange pipes 901 are connected to the cooling medium inlet 902 and the cooling medium outlet 903 respectively via manifolds. Figure 4A As shown, the heat exchanger tube 901 has two U-shaped passes within the reactor, which increases the amount of cooling medium, thereby increasing the heat exchange capacity and efficiency. Figure 4BAs shown, adjacent heat exchange pipes are arranged in an equilateral triangle, with the center-to-center spacing between the pipes being 1 to 2 times their diameter. The diameter of the heat exchange pipes is 10 mm to 25 mm, ensuring an effective heat exchange rate with the reaction mixture. In this embodiment, the distance between the inner heat exchange pipe near the center of the reactor and the outer edge of the impeller is 20 mm to 60 mm, and the distance between the outer heat exchange pipe near the reactor shell and the inner wall of the reactor is 50 mm to 100 mm. Too close a distance between the heat exchange pipe and the outer edge of the impeller can easily lead to collision, while too large a distance cannot meet the heat exchange requirements. In the cooling system of this invention, the arrangement of the heat exchange pipes is safe and reasonable, and can meet the heat exchange requirements of the acetone cyanohydrin acylation reaction.

[0053] The reactor in this embodiment also includes a cooling jacket 801 disposed outside the reactor shell, through which the cooling medium flows from the bottom inlet 802 to the top outlet 803.

[0054] Figures 5-6 The control system of the acetone cyanohydrin acylation reactor of this embodiment is shown, including: temperature detection controller 10, acetone cyanohydrin feed control unit 11, sulfuric acid feed control unit 12, temperature anomaly controller 13, and cooling medium flow rate regulation unit 14.

[0055] The temperature detection controller 10 is connected to the cooling medium flow regulation unit 14 and the temperature anomaly controller 13. The temperature anomaly controller 13 is further connected to the acetone cyanohydrin feed control unit 11.

[0056] The acetone cyanohydrin feed control unit 11 includes an acetone cyanohydrin controller 1101 and an acetone cyanohydrin feed regulating valve 1102 installed on each of the acetone cyanohydrin feed pipelines a1-a4. The acetone cyanohydrin controller 1101 controls the opening degree of each acetone cyanohydrin feed regulating valve 1102 according to the settings, so as to precisely regulate the acetone cyanohydrin feed ratio at each stage.

[0057] The cooling medium flow regulating unit 14 includes a cooling medium regulating valve 14a for the hot water pipe connected to the cooling medium outlet of the hot water pipe, and a cooling medium regulating valve 14b for the cooling jacket connected to the cooling medium outlet of the cooling jacket.

[0058] In existing technologies, reaction temperatures are generally controlled between 95℃ and 115℃. This invention precisely controls the set allowable range of 95℃ to 105℃ to reduce the occurrence of side reactions. The temperature detection controller 10 includes four temperature sensors T1-T4 for detecting the temperature in different areas within the reactor. When the difference between the temperature measured by any temperature sensor and the maximum limit temperature (e.g., 105℃) is greater than 0 but less than the set allowable range (e.g., 2℃), the temperature detection controller 10 adjusts the opening of the cooling medium regulating valve 14a of the hot water exchange pipe and the cooling medium regulating valve 14b of the cooling jacket, thereby increasing the cooling medium flow rate to control heat exchange and temperature. When the temperature difference exceeds the set allowable range, i.e., the reading at the highest temperature test point exceeds the set temperature (e.g., 105℃) by more than 2℃, the temperature detection controller 10 feeds back the highest point temperature to the temperature anomaly controller 13. The temperature anomaly controller 13 controls the acetone cyanohydrin feed control unit 11 to reduce the acetone cyanohydrin feed rate in the area corresponding to the highest point temperature, restoring the temperature to normal. Furthermore, the total amount of acetone cyanohydrin feed at each stage is fed back to the sulfuric acid feed control unit 12. The sulfuric acid feed control unit 12 adjusts the sulfuric acid feed rate to control the total acetone cyanohydrin feed rate and sulfuric acid feed ratio within the design range. After the temperature returns to the set allowable range, it automatically switches back to the temperature detection and control mode.

[0059] The working principle of the control system in this embodiment is as follows:

[0060] (1) Set the feed ratio of each stage of acetone cyanohydrin and the ratio of the total feed amount of acetone cyanohydrin to the feed amount of sulfuric acid. The acetone cyanohydrin control unit 11 adjusts the opening degree of each acetone cyanohydrin feed regulating valve 1102 according to the set conditions to accurately control the feed ratio between each stage of acetone cyanohydrin.

[0061] (2) Set the reaction temperature and the allowable range of the difference between the temperature measured by the temperature detection controller 10 and the reaction temperature. Throughout the reaction process, the temperature detection controller 10 detects the temperature in different areas of the reactor and compares the difference between the measured temperature and the set reaction temperature.

[0062] (3) When the temperature difference is within the set allowable range, the temperature detection controller 10 adjusts the opening of the cooling medium regulating valve and controls the heat exchange and temperature by the flow rate of the cooling medium.

[0063] (4) When the temperature difference exceeds the set allowable range, the temperature detection controller 10 feeds a signal back to the temperature anomaly controller 13. The temperature anomaly controller 13 receives the signal from the temperature detection controller 10 and feeds back the highest temperature value to the acetone cyanohydrin controller 1101. Based on the highest temperature value fed back by the temperature anomaly controller 13, the acetone cyanohydrin controller 1101 controls the acetone cyanohydrin feed regulating valve 1102 of the corresponding area to reduce the acetone cyanohydrin feed rate and adjust the temperature to return to normal. After the temperature returns to the set allowable range, it automatically switches back to the temperature detection controller control mode.

[0064] (5) At the same time, the acetone cyanohydrin controller 1101 feeds back the amount of each acetone cyanohydrin feed to the sulfuric acid feed controller 1201, adjusts the opening of the sulfuric acid feed regulating valve 1202, and controls the total amount of acetone cyanohydrin feed and the ratio of sulfuric acid feed within the design range.

[0065] The control system of this invention enables temperature control and reaction feed control. Temperature control, through the coordinated action of cooling medium flow control and acetone cyanohydrin (ACE) stage feed control, precisely controls and regulates the temperature of each feed zone, thereby achieving precise temperature control in all areas of the reactor. Reaction feed control includes the distribution control between multiple ACE cyanohydrin feed stages and the control of the ratio of total ACE cyanohydrin feed to sulfuric acid feed (reaction ratio). Based on the set parameters, the distribution between each ACE cyanohydrin feed stage and the ratio of total ACE cyanohydrin feed to sulfuric acid feed are precisely controlled.

[0066] The process of carrying out the acetone cyanohydrin acylation reaction using the acetone cyanohydrin acylation reactor in this embodiment is as follows:

[0067] 100% sulfuric acid is metered by the sulfuric acid feed control unit 12 and enters the sulfuric acid feed inlet 5. After the agitator 2 is started and the liquid level rises, acetone cyanohydrin is metered by the acetone cyanohydrin feed unit 11 and enters the acetone cyanohydrin feed inlet 4. It is then distributed in the reactor through the acetone cyanohydrin distributor 3. After the acetone cyanohydrin flows out of the acetone cyanohydrin distributor, it is immediately dispersed again by the blades 2041, 2042, 2043, and 205 above the acetone cyanohydrin distributor, and is uniformly mixed with the sulfuric acid in the reactor. The reaction of sulfuric acid and acetone cyanohydrin is exothermic, causing the temperature of the reactants to rise. Circulating cooling water is introduced into the reactor from the cooling jacket inlet 802 and flows out from the cooling jacket outlet 803. Circulating cooling water is also introduced into the reactor from the heat exchanger pipe outlet 902 and flows out from the heat exchanger pipe outlet 903. The flow rates of the cooling water in the cooling jacket 801 and the heat exchanger pipe 901 are regulated by cooling medium regulating valves 14a and 14b, respectively. The temperature monitoring controller 10 controls the opening of the cooling medium regulating valves based on the temperature difference measured by temperature sensors T1-T4, maintaining the reaction temperature between 95℃ and 105℃. When the reactant level rises to the liquid outlet 7, it flows out from the liquid outlet, and the gas produced by the reaction of sulfuric acid and acetone cyanohydrin is discharged from the gas outlet 6.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An acetone cyanohydrin acylation reactor, comprising a shell, a stirrer, a cooling system, and an acetone cyanohydrin distributor, wherein the shell is provided with an acetone cyanohydrin inlet, a sulfuric acid inlet, and a liquid outlet, the acetone cyanohydrin inlet being connected to the acetone cyanohydrin distributor, and the stirrer comprising a motor, a stirring shaft, and impellers disposed on the stirring shaft, characterized in that, The blades include a combination of axial blades, radial blades and dispersion blades. The dispersion blades include multiple blades, and the blades are three-sectioned, namely a horizontal section, a main body section and a bending section. The main body section is 5 / 6 to 4 / 5 of the total blade length, and it is inclined upward at an angle of 5° to 10°; the horizontal section is 1 / 6 to 1 / 5 of the total blade length; the bending section is 1 / 6 to 1 / 5 of the total blade length, and the angle between the bending section and the main body section is 10° to 20°. The blades include at least two sets, wherein the lowest set includes an axial blade and a dispersion blade, the dispersion blade being located below the axial blade, and the remaining sets include an axial blade and a radial blade. The acetone cyanohydrin distributor is located below the blade, and the distance between the top of the acetone cyanohydrin distributor and the bottom of the blade is 20mm to 80mm. The inner diameter of the acetone cyanohydrin distributor is 0.8 to 1.2 times the diameter of the blade. The acetone cyanohydrin distributor includes at least two, which are respectively located below the radial blade and the dispersion blade.

2. The reactor according to claim 1, characterized in that, The distance between two adjacent blades is 1 to 2 times the blade diameter. The uppermost blade is located below the liquid outlet, and the distance between it and the liquid outlet is 1.5 to 2 times the blade diameter.

3. The reactor according to claim 1, characterized in that, The diameter of the impeller is 1 / 4 to 1 / 3 of the reactor diameter.

4. The reactor according to claim 1, characterized in that, The acetone cyanohydrin distributor is annular, with two rows of holes arranged alternately along the circumference of the bottom surface.

5. The reactor according to claim 4, characterized in that, The included angle between the two rows of holes is 90°~130°, the diameter of the holes is 8mm~15mm, and the center distance between two adjacent holes is 2~3 times the diameter of the holes.

6. The reactor according to claim 1, characterized in that, The cooling system includes multiple sets of hot water exchange pipes, which are U-shaped and arranged in an equilateral triangle with a center-to-center distance of 1 to 2 times the diameter of the hot water exchange pipe.

7. The reactor according to claim 6, characterized in that, The hot water exchange pipes consist of 3 to 8 sets, and the diameter of the hot water exchange pipes is 10mm to 25mm.

8. The reactor according to claim 6, characterized in that, The distance between the inner hot water exchange pipe and the outer edge of the impeller is 20mm~60mm, and the distance between the outer hot water exchange pipe and the inner wall of the reactor is 50mm~100mm.

9. The reactor according to claim 6, characterized in that, The cooling system also includes a cooling jacket disposed outside the housing.

10. The reactor according to claim 1, characterized in that, The reactor has a length-to-diameter ratio of 5 to 10.

11. A control system for the acetone cyanohydrin acylation reactor according to claim 1, characterized in that, Includes a temperature detection controller, a temperature anomaly controller, an acetone cyanohydrin feed control unit, and a cooling medium flow regulation unit; The temperature detection controller is connected to the cooling medium flow regulation unit and the temperature anomaly controller respectively, and the temperature anomaly controller is connected to the acetone cyanohydrin feed control unit; The temperature detection controller includes multiple temperature sensors arranged in different areas of the reactor to detect the temperature in different areas of the reactor. When the temperature difference between different areas is greater than 0 and less than a set allowable range, the temperature detection controller feeds back the highest temperature to the cooling medium flow rate regulation unit, which increases the cooling medium flow rate. When the temperature difference between different areas exceeds the set allowable range, the temperature detection controller feeds back the highest temperature to the temperature anomaly controller. The acetone cyanohydrin feed control unit includes multiple units, corresponding to the temperature sensors. The temperature anomaly controller controls the acetone cyanohydrin feed control unit based on the highest temperature fed back by the temperature detection controller. The acetone cyanohydrin feed control unit reduces the acetone cyanohydrin feed rate in the region corresponding to the highest temperature. After the temperature returns to the set allowable range, it automatically switches back to the temperature detection controller control mode.

12. The control system according to claim 11, characterized in that, It also includes a sulfuric acid feed control unit, which is connected to the acetone cyanohydrin feed control unit. The sulfuric acid feed rate is adjusted according to the total acetone cyanohydrin feed rate, and the ratio of the total acetone cyanohydrin feed rate to the sulfuric acid feed rate is controlled within a set range.

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