A static mixing device and method for phosgene and organic amine

Abstract

The present invention discloses a static mixing device and method for phosgene and organic amine, wherein the static mixing device comprises a conduit for limiting a fluid flow path and a baffle region inside the conduit; the baffle region is a length region in a tube composed of baffle blocks and baffle plates distributed at intervals. The static mixing device of the present invention can enhance radial turbulence under a relatively small pressure energy loss, thereby comprehensively solving the technical problems proposed by the present invention.

Description

Technical Field

[0001] The invention relates to a mixing device and a method, and in particular to a static mixing device and a method for mixing phosgene and an organic amine. Background Art

[0002] In industry, phosgene and polyamine compounds are usually used to react in a solvent to prepare isocyanates. In large-scale industrial processes, the amount of phosgene and solvent used is often greatly excessive to ensure that the reaction is fully carried out and to avoid the generation of by-products. However, phosgene and solvent often need to be removed in the subsequent process to obtain a high-purity isocyanate product, and this process often consumes a lot of energy. Therefore, reducing the excess rate of phosgene and solvent as much as possible is of great significance to reducing the production cost and process difficulty of isocyanates.

[0003] The reaction of phosgene with organic amines to produce isocyanates usually involves two reaction steps. The first step occurs mainly at low temperatures, and the main product is carbamoyl chloride. The second step occurs mainly at high temperatures, and carbamoyl chloride decomposes under heat to produce isocyanates.

[0004] The study found that the reaction of phosgene with organic amines to form isocyanates releases a byproduct of hydrogen chloride, which is easy to react with organic amines to form amine hydrochlorides with low solubility and precipitate in the solvent. The reaction rate of this solid substance with phosgene is significantly lower than that of the organic amine with phosgene, resulting in the unconverted amine hydrochlorides contacting with isocyanates in the subsequent reaction process to produce urea byproducts. When the side reaction is effectively suppressed, the excess rate of phosgene and solvent can be effectively reduced.

[0005] Patent CN102802773A discloses a static phosgene mixer, in which a guide element occupies the center of an otherwise tubular conduit, and when the phosgene passes through the guide element, the circular phosgene flow path is converted into an annular phosgene flow path; and organic polyamines are introduced through multiple nozzles located in the section where the annular phosgene flow path exists, thereby reducing the occurrence of side reactions by increasing the turbulence of the internal fluid.

[0006] Patent CN104010720A discloses a highly isolated jet mixer for phosgenation of amines, which provides a conduit with jet holes on the inner or outer surface, thereby improving the mixing speed and reducing the generation of undesirable by-products.

[0007] However, the lack of radial mixing effect in the existing design of the conduit leads to the inevitable formation of a stagnant flow zone near the wall, causing hydrogen chloride to react with organic amines to form amine hydrochlorides. On the other hand, the process of preparing isocyanates by the mixed reaction of phosgene and organic amines will produce a large amount of gas phase, mainly because the reaction exotherm causes the liquid phase temperature to rise, the flow in the mixer produces resistance loss, resulting in a pressure drop, and the phosgene dissolved in the liquid phase vaporizes. Phosgene vaporization will cause the phosgene concentration in the liquid phase to decrease, and the possibility of contact between organic amines and liquid phase phosgene will decrease. The energy barrier of the reaction between gas phase phosgene and organic amines is high, resulting in a decrease in the reaction rate, making the side reaction of organic amines and hydrogen chloride more likely to occur. Therefore, it is necessary not only to study how to enhance the mixing effect of phosgene and organic amines, but also to ensure that the pressure drop during the mixing process is small, thereby reducing the adverse effect of the vaporization process of the mixed stream on the reaction effect. Summary of the invention

[0008] In order to solve the above technical problems, the present invention firstly proposes a static mixing device for phosgene and organic amine.

[0009] The invention also provides a method for producing isocyanate by using a static mixing device of phosgene and organic amine.

[0010] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0011] A static mixing device for phosgene and organic amines, comprising a conduit for defining a fluid flow path and a baffle region inside the conduit; the baffle region is a length region inside a tube formed by baffle blocks (4) and baffle plates (5) distributed at intervals; the conduit comprises an inlet end for introducing an axially flowing raw material flow and an outlet end for removing a product flow;

[0012] The baffle block (4) is divided into an upper baffle block (41) and a lower baffle block (42), which are symmetrical up and down along the horizontal axis of the conduit and have a gap in the middle to form a fluid channel;

[0013] In a radial longitudinal section of the catheter with the midline of the baffle block (4) as a tangent, the upper baffle block (41) and the lower baffle block (42) are in an arc shape that is symmetrical up and down, and the arc of the arc is in close contact with the inner wall of the catheter;

[0014] In the axial longitudinal section of the catheter, the lower edge of the upper baffle block (41) is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the upper end of the catheter through the arcuate surfaces; the upper edge of the lower baffle block (42) is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the lower end of the catheter through the arcuate surfaces;

[0015] The baffle (5) is fixedly installed along the radial direction of the conduit, and its front and rear side surfaces are symmetrical convex surfaces; in the axial longitudinal section of the conduit, the baffle (5) is in the shape of a shuttle with pointed upper and lower ends and a wide middle;

[0016] In a radial longitudinal section of the conduit with the midline of the baffle (5) as a tangent, the baffle (5) is in an arc-shaped structure with the upper and lower sides being horizontal and the two ends being in close contact with the inner wall of the conduit; arc-shaped notches are respectively formed between the upper and lower sides of the baffle (5) and the inner wall of the conduit to serve as a fluid channel;

[0017] A front guide piece (3) and a rear guide piece (6) are respectively arranged at the front and rear ends of the baffle area; a plurality of nozzles (2) are also arranged at the front end of the baffle area, and the plurality of nozzles are distributed in a ring shape along the side wall of the conduit.

[0018] As a preferred embodiment of the static mixing device of the present invention, the front flow guide (3) and the rear flow guide (6) are both conical, and they are aligned with the central axis of the conduit; the cone vertex angle of the front flow guide (3) is at the front, and the cone vertex angle of the rear flow guide (6) is at the rear, and the two are distributed in opposite directions; the front flow guide (3) and the rear flow guide (6) respectively form annular channels for feeding and discharging with the inner wall of the conduit;

[0019] Preferably, the cone vertex angles of the front flow guide (3) and the rear flow guide (6) are in the range of 25-75°, preferably 40-60°;

[0020] Preferably, the diameter of the conical bottom surface of the front flow guide (3) and the rear flow guide (6) is 90-95% of the inner diameter of the conduit, preferably 92-93%.

[0021] As a preferred embodiment of the static mixing device of the present invention, the nozzle is located at the rear end of the front guide member (3), and the vertical distance from the center point of the ring formed by the multiple nozzles to the bottom surface of the front guide member (3) is 20-40 mm;

[0022] Preferably, the number of the nozzles is 5-20;

[0023] Preferably, the nozzle has a diameter of 5-30 mm, preferably 10-25 mm.

[0024] As a preferred embodiment of the static mixing device of the present invention, the baffle area starts from the first pair of baffle blocks and ends with the last pair of baffle blocks, so that the flow path formed after the baffle area is connected with the front guide member (3) and the rear guide member (6) is smooth;

[0025] Preferably, the number of the baffles is 4-9 pairs;

[0026] Preferably, adjacent baffles on the same side of the conduit are smoothly connected or spaced apart from each other; more preferably, the spacing distance between adjacent baffles on the same side of the conduit is 0.1-0.8 times the inner diameter of the conduit.

[0027] As a preferred embodiment of the static mixing device of the present invention, in a radial longitudinal section of the conduit with the center line of the baffle (4) as a tangent, the gap area (i.e., the flow area) S1 between the upper baffle (41) and the lower baffle (42) is 10-30% of the conduit cross-sectional area S0;

[0028] Preferably, in the radial longitudinal section of the catheter with the center line of the baffle (5) as the tangent, the total area S2 of the arc-shaped notches on the upper and lower sides of the baffle (5) is greater than or equal to the notch area S1 between the upper baffle block (41) and the lower baffle block (42).

[0029] As a preferred solution in the static mixing device of the present invention, the height of the baffle plate (5) is greater than the spacing height between the lower edge of the upper baffle block (41) and the upper edge of the lower baffle block (42);

[0030] Preferably, the center thickness of the baffle (5) is 10-30 mm.

[0031] As a preferred embodiment of the static mixing device of the present invention, the axial length of the baffle area is 5-15 times the inner diameter of the conduit;

[0032] Preferably, the diameter of the conduit is 100-500 mm, preferably 200-400 mm.

[0033] A method for producing isocyanate using the static mixing device of phosgene and organic amine as described above comprises the following steps:

[0034] An axially flowing phosgene flow is introduced from the inlet end of the conduit, and at the same time, an organic amine flow is injected into the conduit from a nozzle, so that the phosgene flow is mixed with the organic amine flow after diversion and fully mixed and reacted through multi-stage deflection to produce isocyanate.

[0035] As a preferred embodiment of the static mixing device of the present invention, the feed temperature of the phosgene flow is -20°C to 30°C, and the operating pressure is 0.3-4Mpag;

[0036] Preferably, the feed temperature of the organic amine stream is 45-120°C and the operating pressure is 0.35-4.05Mpag;

[0037] Preferably, the feed amounts of the phosgene flow and the organic amine flow are 1.1-4 in terms of the mass ratio of phosgene to organic amine.

[0038] As a preferred embodiment of the static mixing device of the present invention, the phosgene flow is pure phosgene or a mixture of phosgene and a solvent; preferably, the phosgene mass content in the phosgene flow is 60-99%, preferably 70-80%;

[0039] Preferably, the organic amine stream is a mixture of an organic amine and a solvent, wherein the mass content of the organic amine is 35-75%, preferably 55-65%;

[0040] Preferably, the organic amine is selected from one or more of toluenediamine, diphenylmethanediamine, 1,6-hexanediamine, polymethylene polyphenyl polyamines, and meta-xylylenediamine;

[0041] Preferably, the solvent is selected from at least one of chlorobenzene, dichlorobenzene, diethyl carbonate, dimethyl carbonate and toluene.

[0042] Research has found that simply increasing the turbulence in the radial direction of the conduit by setting baffles will lead to a large loss of pressure energy, which will cause the phosgene dissolved in the solvent to vaporize, thereby deteriorating the reaction effect. The static mixing device of the present invention can enhance the radial turbulence with a small loss of pressure energy, thereby comprehensively solving the technical problems proposed by the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the internal structure of the axial longitudinal section of the conduit in the static mixing device of Example 1.

[0044] Figure 2 This is a schematic structural diagram of a radial longitudinal section of a conduit at the midline of a baffle in a static mixing device in Example 1.

[0045] Figure 3 Schematic diagram of the structure of the radial longitudinal section of the conduit at the midline of the baffle in the static mixing device of Example 1.

[0046] Figure 4 Schematic diagram of the internal structure of the axial longitudinal section of the conduit in the static mixing device of comparative example 1.

[0047] Figure 5 Schematic diagram of the internal structure of the axial longitudinal section of the conduit in the static mixing device of comparative example 2.

[0048] Figure 6 Schematic diagram of the internal structure of the axial longitudinal section of the conduit in the static mixing device of comparative example 3.

[0049] In the figure: 1, conduit; 2, nozzle; 3, front guide piece; 4, deflector; 41, upper deflector; 42, lower deflector; 5, deflector plate; 6, rear guide piece. DETAILED DESCRIPTION

[0050] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0051] Unless otherwise specified, the raw materials in the present invention can be purchased from commercial sources.

[0052] The main test methods used in the following embodiments of the present invention are as follows:

[0053] (1) Determination of hydrochloride content in the reaction liquid at the outlet of the static mixer: The hydrochloride content in the cold reaction was determined by liquid phase. Chromatographic conditions: Agilent 1620, chromatographic column waters C18 (4.6*250mm), DAD detector, detection wavelength 254nm; mobile phase: acetonitrile and water gradient elution. Pretreatment method: Take 0.2g sample, add 2.5g methanol, derivatize at 70 degrees for 60min, pass through a 0.45um organic membrane, and put into a liquid phase vial for liquid phase analysis. The results are quantitatively analyzed in terms of area percentage.

[0054] (2) Method for determining the content of acyl chloride in the reaction liquid at the outlet of the static mixer: Acyl chloride was determined by GPC chromatography, chromatographic conditions: Agilent 1620, chromatographic column PLgel 5um 300*7.5mm, RID detector detection. Pretreatment method: Take 0.1g sample in a liquid phase bottle, add 1ml THF, shake well and analyze by GPC. The results were quantitatively analyzed by the area percentage method.

[0055] (3) Method for measuring pressure energy loss: Add pressure monitoring instruments at 2 pipe diameters upstream and 2 pipe diameters downstream of the static mixer. The pressure energy loss is characterized by the ratio of the difference in the pressure monitoring values ​​at the two locations (static mixer pressure drop) to the inlet pressure of the phosgene flow.

[0056] [Example 1]

[0057] like Figure 1 As shown, a static mixing device for phosgene and organic amines comprises a conduit for defining a fluid flow path and a baffle region inside the conduit; the baffle region is a length region inside the tube formed by baffle blocks 4 and baffle plates 5 distributed at intervals; the conduit comprises an inlet end for introducing an axially flowing raw material flow and an outlet end for removing a product flow;

[0058] The baffle block 4 is divided into an upper baffle block 41 and a lower baffle block 42, which are symmetrical up and down along the horizontal axis of the conduit and have a gap in the middle to form a fluid channel;

[0059] like Figure 2 As shown, in the radial longitudinal section of the catheter with the midline of the baffle block 4 as the tangent, the upper baffle block 41 and the lower baffle block 42 are in an arc shape that is symmetrical up and down, and the arc of the arc is in close contact with the inner wall of the catheter;

[0060] In the axial longitudinal section of the catheter, the lower edge of the upper baffle block 41 is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the upper end of the catheter through the arcuate surfaces; the upper edge of the lower baffle block 42 is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the lower end of the catheter through the arcuate surfaces;

[0061] The baffle plate 5 is fixedly installed along the radial direction of the conduit, and its front and rear side surfaces are symmetrical convex surfaces; in the axial longitudinal section of the conduit, the baffle plate 5 is in the shape of a shuttle with sharp ends at the top and bottom and a wide middle;

[0062] like Figure 3 As shown, in the radial longitudinal section of the conduit with the midline of the baffle 5 as the tangent, the baffle 5 is in an arc-shaped structure with the upper and lower sides being horizontal and the two ends being in contact with the inner wall of the conduit; arc-shaped notches are formed between the upper and lower sides of the baffle 5 and the inner wall of the conduit, respectively, as fluid channels;

[0063] The front and rear ends of the deflection area are respectively provided with a front guide member 3 and a rear guide member 6; the front end of the deflection area is also provided with a plurality of nozzles 2, which are distributed in a ring shape along the side wall of the conduit.

[0064] The front guide piece 3 and the rear guide piece 6 are both conical, and they are aligned with the central axis of the conduit; the cone vertex angle of the front guide piece 3 is in the front, and the cone vertex angle of the rear guide piece 6 is in the rear, and the two are distributed in opposite directions; the front guide piece 3 and the rear guide piece 6 form annular channels for feeding and discharging materials with the inner wall of the conduit respectively;

[0065] Specifically, the angle range of the cone vertex angle of the front guide member 3 and the rear guide member 6 is 45°, and the diameter of their cone bottom surface is 90% of the inner diameter of the conduit;

[0066] Specifically, the nozzle is located at the rear end of the front guide member 3, and the vertical distance from the center point of the ring surrounded by the multiple nozzles to the bottom surface of the front guide member 3 is 20 mm;

[0067] Specifically, the number of the nozzles 2 is 12, and the nozzles are circular with a diameter of 15 mm.

[0068] Specifically, the baffle area starts from the first pair of baffle blocks and ends with the last pair of baffle blocks, so that the flow path formed after the baffle blocks are connected with the front guide member 3 and the rear guide member 6 is smooth; the number of the baffle blocks is 7 pairs;

[0069] Specifically, adjacent baffle blocks on the same side of the conduit are spaced apart from each other; and the spacing distance between adjacent baffle blocks on the same side of the conduit is 0.4 times the inner diameter of the conduit.

[0070] Specifically, in the radial longitudinal section of the conduit with the midline of the baffle block 4 as the tangent, the gap area (i.e., the flow area) S1 between the upper baffle block 41 and the lower baffle block 42 is 20% of the conduit cross-sectional area S0;

[0071] Specifically, in the radial longitudinal section of the catheter with the center line of the baffle 5 as the tangent, the total area S2 of the arc-shaped notches on the upper and lower sides of the baffle 5 is equal to the notch area S1 between the upper baffle block 41 and the lower baffle block 42.

[0072] Specifically, the height of the baffle plate 5 is greater than the spacing height between the lower edge of the upper baffle block 41 and the upper edge of the lower baffle block 42;

[0073] Specifically, the center thickness of the baffle plate 5 is 10 mm.

[0074] Specifically, the axial length of the baffle area is 15 times the inner diameter of the catheter;

[0075] Preferably, the diameter of the conduit is 200 mm.

[0076] [Example 2]

[0077] A static mixing device for phosgene and organic amines, comprising a conduit for defining a fluid flow path and a baffle area inside the conduit; the baffle area is a length area in the tube composed of baffle blocks 4 and baffle plates 5 distributed at intervals; the conduit comprises an inlet end for introducing an axially flowing raw material flow and an outlet end for removing a product flow;

[0078] The baffle block 4 is divided into an upper baffle block 41 and a lower baffle block 42, which are symmetrical up and down along the horizontal axis of the conduit and have a gap in the middle to form a fluid channel;

[0079] In the radial longitudinal section of the catheter with the midline of the baffle block 4 as the tangent, the upper baffle block 41 and the lower baffle block 42 are in an arc shape that is symmetrical up and down, and the arc of the arc is in close contact with the inner wall of the catheter;

[0080] In the axial longitudinal section of the catheter, the lower edge of the upper baffle block 41 is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the upper end of the catheter through the arcuate surfaces; the upper edge of the lower baffle block 42 is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the lower end of the catheter through the arcuate surfaces;

[0081] The baffle plate 5 is fixedly installed along the radial direction of the conduit, and its front and rear side surfaces are symmetrical convex surfaces; in the axial longitudinal section of the conduit, the baffle plate 5 is in the shape of a shuttle with sharp ends at the top and bottom and a wide middle;

[0082] In the radial longitudinal section of the conduit with the midline of the baffle 5 as the tangent, the baffle 5 is in an arc-shaped structure with the upper and lower parts being horizontal and the two ends being in contact with the inner wall of the conduit; arc-shaped gaps are formed between the upper and lower sides of the baffle 5 and the inner wall of the conduit, respectively, as fluid channels;

[0083] The front and rear ends of the deflection area are respectively provided with a front guide member 3 and a rear guide member 6; the front end of the deflection area is also provided with a plurality of nozzles 2, which are distributed in a ring shape along the side wall of the conduit.

[0084] The front guide piece 3 and the rear guide piece 6 are both conical, and they are aligned with the central axis of the conduit; the cone vertex angle of the front guide piece 3 is in the front, and the cone vertex angle of the rear guide piece 6 is in the rear, and the two are distributed in opposite directions; the front guide piece 3 and the rear guide piece 6 form annular channels for feeding and discharging materials with the inner wall of the conduit respectively;

[0085] Specifically, the angle range of the cone vertex angle of the front flow guide 3 and the rear flow guide 6 is 25°, and the diameter of their cone bottom surface is 95% of the inner diameter of the conduit;

[0086] Specifically, the nozzle is located at the rear end of the front guide member 3, and the vertical distance from the center point of the ring surrounded by the multiple nozzles to the bottom surface of the front guide member 3 is 30 mm;

[0087] Specifically, the number of the nozzles 2 is 5, and the nozzles are circular with a diameter of 30 mm.

[0088] Specifically, the baffle area starts from the first pair of baffle blocks and ends with the last pair of baffle blocks, so that the flow path formed after the baffle blocks are connected with the front guide member 3 and the rear guide member 6 is smooth; the number of the baffle blocks is 5 pairs;

[0089] Specifically, adjacent baffle blocks on the same side of the conduit are spaced apart from each other; and the spacing distance between adjacent baffle blocks on the same side of the conduit is 0.8 times the inner diameter of the conduit.

[0090] Specifically, in the radial longitudinal section of the conduit with the midline of the baffle block 4 as the tangent, the gap area (i.e., the flow area) S1 between the upper baffle block 41 and the lower baffle block 42 is 10% of the conduit cross-sectional area S0;

[0091] Specifically, in the radial longitudinal section of the catheter with the center line of the baffle 5 as the tangent, the total area S2 of the arc-shaped notches on the upper and lower sides of the baffle 5 is equal to the notch area S1 between the upper baffle block 41 and the lower baffle block 42.

[0092] Specifically, the height of the baffle plate 5 is greater than the spacing height between the lower edge of the upper baffle block 41 and the upper edge of the lower baffle block 42;

[0093] Specifically, the center thickness of the baffle plate 5 is 30 mm.

[0094] Specifically, the axial length of the baffle area is 5 times the inner diameter of the catheter;

[0095] Preferably, the diameter of the conduit is 100 mm.

[0096] [Example 3]

[0097] A static mixing device for phosgene and organic amines, comprising a conduit for defining a fluid flow path and a baffle area inside the conduit; the baffle area is a length area in the tube composed of baffle blocks 4 and baffle plates 5 distributed at intervals; the conduit comprises an inlet end for introducing an axially flowing raw material flow and an outlet end for removing a product flow;

[0098] The baffle block 4 is divided into an upper baffle block 41 and a lower baffle block 42, which are symmetrical up and down along the horizontal axis of the conduit and have a gap in the middle to form a fluid channel;

[0099] In the radial longitudinal section of the catheter with the midline of the baffle block 4 as the tangent, the upper baffle block 41 and the lower baffle block 42 are in an arc shape that is symmetrical up and down, and the arc of the arc is in close contact with the inner wall of the catheter;

[0100] In the axial longitudinal section of the catheter, the lower edge of the upper baffle block 41 is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the upper end of the catheter through the arcuate surfaces; the upper edge of the lower baffle block 42 is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the lower end of the catheter through the arcuate surfaces;

[0101] The baffle plate 5 is fixedly installed along the radial direction of the conduit, and its front and rear side surfaces are symmetrical convex surfaces; in the axial longitudinal section of the conduit, the baffle plate 5 is in the shape of a shuttle with sharp ends at the top and bottom and a wide middle;

[0102] In the radial longitudinal section of the conduit with the midline of the baffle 5 as the tangent, the baffle 5 is in an arc-shaped structure with the upper and lower parts being horizontal and the two ends being in contact with the inner wall of the conduit; arc-shaped gaps are formed between the upper and lower sides of the baffle 5 and the inner wall of the conduit, respectively, as fluid channels;

[0103] The front and rear ends of the deflection area are respectively provided with a front guide member 3 and a rear guide member 6; the front end of the deflection area is also provided with a plurality of nozzles 2, which are distributed in a ring shape along the side wall of the conduit.

[0104] The front guide piece 3 and the rear guide piece 6 are both conical, and they are aligned with the central axis of the conduit; the cone vertex angle of the front guide piece 3 is in the front, and the cone vertex angle of the rear guide piece 6 is in the rear, and the two are distributed in opposite directions; the front guide piece 3 and the rear guide piece 6 form annular channels for feeding and discharging materials with the inner wall of the conduit respectively;

[0105] Specifically, the angle range of the cone vertex angle of the front guide member 3 and the rear guide member 6 is 75°, and the diameter of their cone bottom surface is 93% of the inner diameter of the conduit;

[0106] Specifically, the nozzle is located at the rear end of the front guide member 3, and the vertical distance from the center point of the ring surrounded by the multiple nozzles to the bottom surface of the front guide member 3 is 40 mm;

[0107] Specifically, the number of the nozzles 2 is 20, and the nozzles are circular with a diameter of 5 mm.

[0108] Specifically, the baffle area starts from the first pair of baffle blocks and ends with the last pair of baffle blocks, so that the flow path formed after the baffle blocks are connected with the front guide member 3 and the rear guide member 6 is smooth; the number of the baffle blocks is 7 pairs;

[0109] Specifically, adjacent baffles on the same side of the conduit are connected with a smooth transition.

[0110] Specifically, in the radial longitudinal section of the conduit with the midline of the baffle block 4 as the tangent, the gap area (i.e., the flow area) S1 between the upper baffle block 41 and the lower baffle block 42 is 30% of the conduit cross-sectional area S0;

[0111] Specifically, in the radial longitudinal section of the catheter with the center line of the baffle 5 as the tangent, the total area S2 of the arc-shaped notches on the upper and lower sides of the baffle 5 is equal to the notch area S1 between the upper baffle block 41 and the lower baffle block 42.

[0112] Specifically, the height of the baffle plate 5 is greater than the spacing height between the lower edge of the upper baffle block 41 and the upper edge of the lower baffle block 42;

[0113] Specifically, the center thickness of the baffle 5 is 20 mm.

[0114] Specifically, the axial length of the baffle area is 8 times the inner diameter of the catheter;

[0115] Preferably, the diameter of the conduit is 500 mm.

[0116] [Example 4]

[0117] A method for producing isocyanate using the static mixing device in Example 1 comprises the following steps:

[0118] An axially flowing phosgene flow is introduced from the inlet end of the conduit, and at the same time, an organic amine flow is injected into the conduit from a nozzle, so that the phosgene flow is mixed with the organic amine flow after diversion and fully mixed and reacted through multi-stage deflection to produce isocyanate.

[0119] The phosgene stream comprises 60 wt% of phosgene and 40 wt% of o-dichlorobenzene; the feed flow rate of the phosgene stream is 26 kg / s, the feed temperature is -20°C, and the operating pressure is 0.3 Mpag;

[0120] The organic amine logistics includes 75wt% toluenediamine and 25wt% solvent chlorobenzene; the feed flow rate of the organic amine logistics is 6.5kg / s, the feed temperature is 45°C, and the operating pressure is 0.35Mpag;

[0121] After the reaction was completed, the acyl chloride, amine hydrochloride in the reaction solution at the outlet of the static mixer and the pressure drop of the static mixer were monitored. The results are shown in Table 1.

[0122] [Example 5]

[0123] A method for producing isocyanate using the static mixing device in Example 2 comprises the following steps:

[0124] An axially flowing phosgene flow is introduced from the inlet end of the conduit, and at the same time, an organic amine flow is injected into the conduit from a nozzle, so that the phosgene flow is mixed with the organic amine flow after diversion and fully mixed and reacted through multi-stage deflection to produce isocyanate.

[0125] The phosgene stream comprises 70 wt% phosgene and 30 wt% chlorobenzene; the feed flow rate of the phosgene stream is 26 kg / s, the feed temperature is 15° C., and the operating pressure is 3 Mpag;

[0126] The organic amine logistics includes 35 wt% of diphenylmethanediamine and 65 wt% of solvent chlorobenzene; the feed flow rate of the organic amine logistics is 10 kg / s, the feed temperature is 120° C., and the operating pressure is 3.2 Mpag.

[0127] After the reaction was completed, the acyl chloride, amine hydrochloride in the reaction solution at the outlet of the static mixer and the pressure drop of the static mixer were monitored. The results are shown in Table 1.

[0128] [Example 6]

[0129] A method for producing isocyanate using the static mixing device in Example 3 comprises the following steps:

[0130] An axially flowing phosgene flow is introduced from the inlet end of the conduit, and at the same time, an organic amine flow is injected into the conduit from a nozzle, so that the phosgene flow is mixed with the organic amine flow after diversion and fully mixed and reacted through multi-stage deflection to produce isocyanate.

[0131] The phosgene stream comprises 90 wt% of phosgene and 10 wt% of diethyl carbonate; the feed flow rate of the phosgene stream is 26 kg / s, the feed temperature is 30° C., and the operating pressure is 4.0 Mpag;

[0132] The organic amine stream includes 45 wt% of diphenylmethanediamine and 55 wt% of solvent diethyl carbonate; the feed flow rate of the organic amine stream is 23.6 kg / s, the feed temperature is 80° C., and the operating pressure is

[0133] After the reaction was completed, the acyl chloride, amine hydrochloride in the reaction solution at the outlet of the static mixer and the pressure drop of the static mixer were monitored. The results are shown in Table 1.

[0134] [Comparative Example 1]

[0135] A static mixing device for phosgene and organic amines, the structure of which is substantially the same as that of the static mixing device in Example 1, except that, in the axial longitudinal section of the conduit, the baffle is in the shape of a straight strip and does not have an arc surface. Figure 4 shown.

[0136] [Comparative Example 2]

[0137] A static mixing device for phosgene and organic amines, the structure of which is substantially the same as that of the static mixing device in Example 1, except that, in the axial longitudinal section of the conduit, the baffle is in the shape of a straight strip and does not have two convex surfaces. A schematic diagram of the internal structure of the axial longitudinal section of the conduit in the static mixing device is shown in FIG. Figure 5 shown.

[0138] [Comparative Example 3]

[0139] A static mixing device for phosgene and organic amines, the structure of which is substantially the same as that of the static mixing device in Example 1, except that, in the axial longitudinal section of the conduit, the baffle is in the shape of a straight strip and does not have a curved surface; and the baffle is in the shape of a straight strip and does not have two convex surfaces. Figure 6 shown.

[0140] [Comparative Example 4]

[0141] Isocyanate was produced in substantially the same manner as in Example 4, except that the static mixing device provided in Comparative Example 1 was used in the method.

[0142] After the reaction was completed, the acyl chloride, amine hydrochloride in the reaction solution at the outlet of the static mixer and the pressure drop of the static mixer were monitored. The results are shown in Table 1.

[0143] [Comparative Example 5]

[0144] Isocyanate was produced in substantially the same manner as in Example 4, except that the static mixing device provided in Comparative Example 2 was used in the method.

[0145] After the reaction was completed, the acyl chloride, amine hydrochloride in the reaction solution at the outlet of the static mixer and the pressure drop of the static mixer were monitored. The results are shown in Table 1.

[0146] [Comparative Example 6]

[0147] Isocyanate was produced in substantially the same manner as in Example 4, except that the static mixing device provided in Comparative Example 3 was used in the method.

[0148] After the reaction was completed, the acyl chloride, amine hydrochloride in the reaction solution at the outlet of the static mixer and the pressure drop of the static mixer were monitored. The results are shown in Table 1.

[0149] Table 1. Performance test results

[0150]

[0151] It can be concluded from the results in Table 1 that the use of the static mixing device in this case can effectively reduce the pressure loss during the static mixing process, and at the same time obtain an outlet mixed solution with a higher content of acyl chloride and a lower content of hydrochloride, which effectively improves the reaction effect.

[0152] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A static mixing device for phosgene and organic amine, characterized in that: The invention comprises a conduit for defining a fluid flow path and a baffle area inside the conduit; the baffle area is a length area inside the tube formed by baffle blocks (4) and baffle plates (5) distributed at intervals; The baffle block (4) is divided into an upper baffle block (41) and a lower baffle block (42), which are symmetrical up and down along the horizontal axis of the conduit and have a gap in the middle to form a fluid channel; In a radial longitudinal section of the catheter with the midline of the baffle block (4) as a tangent, the upper baffle block (41) and the lower baffle block (42) are in an arc shape that is symmetrical up and down, and the arc of the arc is in close contact with the inner wall of the catheter; In the axial longitudinal section of the catheter, the lower edge of the upper baffle block (41) is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the upper end of the catheter through the arcuate surfaces; the upper edge of the lower baffle block (42) is connected to two arcuate surfaces extending in opposite directions, and is smoothly connected to the inner wall of the lower end of the catheter through the arcuate surfaces; The baffle (5) is fixedly installed along the radial direction of the conduit, and its front and rear side surfaces are symmetrical convex surfaces; in the axial longitudinal section of the conduit, the baffle (5) is in the shape of a shuttle with pointed upper and lower ends and a wide middle; In a radial longitudinal section of the conduit with the midline of the baffle (5) as a tangent, the baffle (5) is in an arc-shaped structure with the upper and lower sides being horizontal and the two ends being in close contact with the inner wall of the conduit; arc-shaped notches are respectively formed between the upper and lower sides of the baffle (5) and the inner wall of the conduit to serve as a fluid channel; A front guide piece (3) and a rear guide piece (6) are respectively arranged at the front and rear ends of the baffle area; a plurality of nozzles (2) are also arranged at the front end of the baffle area, and the plurality of nozzles are distributed in a ring shape along the side wall of the conduit.

2. The static mixing device of phosgene and organic amine according to claim 1, characterized in that: The front flow guide (3) and the rear flow guide (6) are both conical, and they are aligned with the central axis of the conduit; the cone vertex angle of the front flow guide (3) is at the front, and the cone vertex angle of the rear flow guide (6) is at the rear, and the two are distributed in opposite directions; Preferably, the cone vertex angles of the front flow guide (3) and the rear flow guide (6) are in the range of 25-75°, preferably 40-60°; Preferably, the diameter of the conical bottom surface of the front flow guide (3) and the rear flow guide (6) is 90-95% of the inner diameter of the conduit, preferably 92-93%.

3. The static mixing device of phosgene and organic amine according to claim 1 or 2, characterized in that: The nozzle is located at the rear end of the front flow guide (3), and the vertical distance from the center point of the ring formed by the multiple nozzles to the bottom surface of the front flow guide (3) is 20-40 mm; Preferably, the number of the nozzles is 5-20; Preferably, the nozzle has a diameter of 5-30 mm, preferably 10-25 mm.

4. The static mixing device of phosgene and organic amine according to any one of claims 1 to 3, characterized in that: The baffle area starts from the first pair of baffle blocks and ends with the last pair of baffle blocks, so that the flow path formed after the baffle area is connected with the front guide piece (3) and the rear guide piece (6) is smooth; Preferably, the number of the baffles is 4-9 pairs; Preferably, adjacent baffles on the same side of the conduit are smoothly connected or spaced apart from each other; more preferably, the spacing distance between adjacent baffles on the same side of the conduit is 0.1-0.8 times the inner diameter of the conduit.

5. The static mixing device of phosgene and organic amine according to any one of claims 1 to 4, characterized in that: In the radial longitudinal section of the catheter with the midline of the baffle (4) as the tangent, the gap area S1 between the upper baffle (41) and the lower baffle (42) is 10-30% of the catheter cross-sectional area S0; Preferably, in the radial longitudinal section of the catheter with the center line of the baffle (5) as the tangent, the total area S2 of the arc-shaped notches on the upper and lower sides of the baffle (5) is greater than or equal to the notch area S1 between the upper baffle block (41) and the lower baffle block (42).

6. The static mixing device of phosgene and organic amine according to any one of claims 1 to 5, characterized in that: The height of the baffle plate (5) is greater than the spacing height between the lower edge of the upper baffle block (41) and the upper edge of the lower baffle block (42); Preferably, the center thickness of the baffle (5) is 10-30 mm.

7. The static mixing device of phosgene and organic amine according to any one of claims 1 to 6, characterized in that: The axial length of the baffle area is 5-15 times the inner diameter of the catheter; Preferably, the diameter of the conduit is 100-500 mm, preferably 200-400 mm.

8. A method for producing isocyanate using the static mixing device of phosgene and organic amine according to any one of claims 1 to 7, characterized in that: The following steps are involved: An axially flowing phosgene flow is introduced from the inlet end of the conduit, and at the same time, an organic amine flow is injected into the conduit from a nozzle, so that the phosgene flow is mixed with the organic amine flow after diversion and fully mixed and reacted through multi-stage deflection to produce isocyanate.

9. The method according to claim 8, characterized in that The feed temperature of the phosgene stream is -20°C to 30°C, and the operating pressure is 0.3-4Mpag; Preferably, the feed temperature of the organic amine stream is 45-120°C and the operating pressure is 0.35-4.05Mpag; Preferably, the feed amounts of the phosgene flow and the organic amine flow are 1.1-4 in terms of the mass ratio of phosgene to organic amine.

10. The method according to claim 8, characterized in that The phosgene flow is pure phosgene or a mixture of phosgene and a solvent; preferably, the phosgene mass content in the phosgene flow is 60-99%, preferably 70-80%; Preferably, the organic amine stream is a mixture of an organic amine and a solvent, wherein the mass content of the organic amine is 35-75%, preferably 55-65%; Preferably, the organic amine is selected from one or more of toluenediamine, diphenylmethanediamine, 1,6-hexanediamine, polymethylene polyphenyl polyamines, and meta-xylylenediamine; Preferably, the solvent is selected from at least one of chlorobenzene, dichlorobenzene, diethyl carbonate, dimethyl carbonate and toluene.

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