Phosgenation jet reactor and method for producing isocyanate by using phosgenation jet reactor

Abstract

The invention discloses a phosgenation jet reactor and a method for producing isocyanate by using the phosgenation jet reactor, the jet reactor comprises a reaction cavity, and a feed port N1, a feed port N2, a feed port N3 and a discharge port N4 which are arranged on the reaction cavity, the feed port N1 is arranged at the end part in the reaction cavity, and the discharge port N4 is arranged at the end part in the reaction cavity; and the reaction cavity extends to exceed the central axis of the reaction cavity in the extending direction of the end part of the feeding hole N1. According to the invention, the adjusting device is arranged at the end part of the reaction cavity to adjust the distance between the feeding hole N1 and the nozzle outlet of the injection pipe so as to change the flowing sectional area of the material flow, so that the flow speed of the material is changed, the suction capacity of the injector is ensured, and meanwhile, the circulation volume is adjusted to be matched with the corresponding load. The structure of the jet reactor disclosed by the invention can meet load adjustment of different demands, and the reaction effect of isocyanate is not influenced, so that the production trouble of isocyanate is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of jet reactors, and relates to a phosgenation jet reactor and a method for producing isocyanates using the same, and specifically relates to an adjustable phosgenation jet reactor and a method for producing isocyanates using the same. Background Art

[0002] At present, the production of isocyanate is mainly through the reaction of phosgene and organic amine to form isocyanate and hydrogen chloride, and then separate isocyanate and hydrogen chloride. The reaction of phosgene and organic amine has the characteristics of fast reaction rate and large reaction heat release. Therefore, if the mixing speed is slow, it is very easy to produce more coke, and the accumulation of coke will coke and agglomerate on the wall of the reactor, eventually blocking the reactor.

[0003] The throat of the traditional jet reactor used for isocyanate production is a fixed structure. Therefore, changes in reactor load will inevitably lead to a mismatch between the relevant design parameters and the actual operating conditions. Summary of the invention

[0004] In order to improve the above technical problems, the present invention provides a jet reactor, which includes a reaction chamber and a feed port N1, a feed port N2, a feed port N3 and a discharge port N4 arranged on the reaction chamber, wherein:

[0005] The feed port N1 is at an end portion inside the reaction chamber and extends beyond the central axis of the reaction chamber in the direction in which the end portion of the feed port N1 extends.

[0006] According to an embodiment of the present invention, the end of the feed port N2 inside the reaction chamber does not contact the portion of the feed port N1 inside the reaction chamber. Preferably, the end of the feed port N2 inside the reaction chamber does not exceed the central axis of the reaction chamber in the direction in which the end of the feed port N1 extends.

[0007] According to an embodiment of the present invention, the end of the feed port N3 inside the reaction chamber does not contact the portion of the feed port N1 inside the reaction chamber. Preferably, the end of the feed port N3 inside the reaction chamber does not exceed the central axis of the reaction chamber in the direction in which the end of the feed port N1 extends.

[0008] According to an embodiment of the present invention, the end position of the feed port N1 inside the reaction chamber is adjustable. For example, the end position can be adjusted by a rotary drive device (such as a hand wheel).

[0009] According to an embodiment of the present invention, the cross-sectional area of ​​the end of the feed port N1 inside the reaction chamber is smaller than the cross-sectional area of ​​the feed port N1 outside the reaction chamber.

[0010] According to an embodiment of the present invention, the central axis of the feed port N1 in the extension direction of the end portion inside the reaction chamber coincides with the central axis of the reaction chamber in the same direction.

[0011] According to an embodiment of the present invention, the feed port N1 includes a first same-diameter section, a first reduced-diameter section, and a second same-diameter section, one end of the first reduced-diameter section is connected to the first same-diameter section, and the other end of the first reduced-diameter section is connected to the second same-diameter section. The "same-diameter section" means that the diameters of the sections are the same, and the "reduced-diameter section" means that the diameters of the two ends of the section are different, for example, it can be in the shape of a truncated cone.

[0012] According to an embodiment of the present invention, the first same-diameter section, the first reduced-diameter section and the second same-diameter section may be integrally formed.

[0013] According to an embodiment of the present invention, each of the first section with the same diameter and the second section with the same diameter is cylindrical, and the diameter of the first section with the same diameter is greater than the diameter of the second section with the same diameter.

[0014] According to an embodiment of the present invention, the first diameter-reduced section is in a truncated cone shape, and the diameter of the first diameter-reduced section decreases from top to bottom.

[0015] In the present invention, the first reduced diameter section and the second equal diameter section constitute the nozzle portion of the injection pipe of the injection reactor. Preferably, the ratio of the size to diameter of the nozzle is 2-6, and the cone vertex angle of the nozzle is 20°-90°.

[0016] According to an embodiment of the present invention, the distance between the starting point of the first equal-diameter section and the starting point of the first reduced-diameter section is no more than 250 mm.

[0017] According to an embodiment of the present invention, the distance between the starting point of the first equal-diameter section and the end point of the first reduced-diameter section is no more than 400 nm, exemplarily 350 mm.

[0018] According to an embodiment of the present invention, the distance between the starting point of the first section with the same diameter and the end point of the second section with the same diameter does not exceed 450 mm.

[0019] According to an embodiment of the present invention, the end point of the second section of equal diameter is set at a distance of no more than 20 mm from the bottom of the reaction chamber.

[0020] According to an embodiment of the present invention, the ratio of the cross-sectional area of ​​the end of the feed port N1 inside the reaction chamber to the cross-sectional area of ​​the reaction chamber is (0.1-1):1, exemplarily 1:1.

[0021] According to an embodiment of the present invention, the discharge port N4 is disposed at the tail of the reaction chamber and is not in contact with the portion of the feed port N1 in the reaction chamber.

[0022] According to an embodiment of the present invention, the pressure in the reaction chamber is -0.55 MPa to -0.35 MPa, exemplified by -0.55 MPa, -0.50 MPa, -0.45 MPa, -0.40 MPa, and -0.35 MPa.

[0023] According to an embodiment of the present invention, the average flow rate of the raw material liquid added from the feed port N1 into the reaction chamber is 5 to 60 m / s, exemplified by 5 m / s, 10 m / s, 15 m / s, and 20 m / s.

[0024] According to an embodiment of the present invention, the ratio of the flow rate of the raw material liquid at the outlet of the feed port N1 to the flow rate of the raw material at the outlet of the feed port N2 is 1:1 to 6:1, exemplified by 1:1, 2:1, 3:1, 4:1, 5:1, and 6:1.

[0025] According to an embodiment of the present invention, the average flow rate of the feed inlet N2 is 5 to 10 m / s, exemplified by 5 m / s, 6 m / s, 7 m / s, 8 m / s, 9 m / s, and 10 m / s.

[0026] In the present invention, the feed port N1 can be used, for example, for the addition of amines having the general formula R(NH2)n during the phosgenation reaction; the feed port N2 can be used for the addition of phosgene; and the reflux liquid during the phosgenation reaction re-enters the reaction chamber from the feed port N3 for reaction.

[0027] The jet reactor of the present invention adjusts the position of the feed port N1 from the nozzle outlet of the jet pipe by rotating the hand wheel of the regulating device, thereby changing the cross-sectional area of ​​the material flow and further changing the flow rate of the material.

[0028] According to an embodiment of the present invention, the jet reactor is a phosgenation jet reactor, for example, a jet reactor for isocyanate production.

[0029] The present invention also provides the above-mentioned jet reactor for phosgenation reaction, for example, for preparing isocyanate by phosgenation reaction.

[0030] According to an embodiment of the present invention, the isocyanate has a structure as shown in the following formula I:

[0031] R(NCO)n

[0032] Wherein: R is an aliphatic, alicyclic or aromatic hydrocarbon group having 1 to 15 carbon atoms, and n is an integer from 1 to 3.

[0033] In one embodiment of the present invention, the isocyanate is selected from any one of the following compounds: 1,4-butanediisocyanate, 1,6-hexanediisocyanate, 1,4-diisocyanatocyclohexane, isophoronediisocyanate, 4,4'-dicyclohexylmethanediisocyanate, triisocyanatononane or toluenediisocyanate.

[0034] The present invention also provides a method for preparing isocyanate, which comprises: in the above-mentioned jet reactor, reacting an amine having the general formula R(NH2)n with phosgene in a reaction chamber, and adjusting the end position of the feed port N1 inside the reaction chamber by an adjusting device, thereby changing the cross-sectional area of ​​the material flow, and then changing the flow rate of the material.

[0035] According to an embodiment of the present invention, the amine of R(NH2)n is selected from any one of the following compounds: 1,4-butanediamine, 1,6-hexanediamine, 1,4-diaminocyclohexane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 4,4'-dicyclohexylmethanediamine, triaminononane, a 2,4- / 2,6-toluenediamine mixture with an isomer ratio of 80 / 20-65 / 35 or pure 2,4-toluenediamine.

[0036] According to an embodiment of the present invention, the amine of R(NH2)n is added to the reactor in the form of a solution. For example, the solvent used in the amine solution of R(NH2)n is selected from chlorobenzene, toluene, xylene, o-dichlorobenzene or decalin.

[0037] According to an embodiment of the present invention, the amine solution of R(NH2)n is added into the reactor from the feed port N1.

[0038] According to an embodiment of the present invention, the average flow rate of the amine solution of R(NH2)n is 10 to 50 m / s, exemplified by 10 m / s, 20 m / s, 30 m / s, 40 m / s, and 50 m / s.

[0039] According to an embodiment of the present invention, the phosgene is added to the reactor from the feed port N2. For example, the average flow rate of the phosgene is 5 to 10 m / s, exemplified by 5 m / s, 6 m / s, 7 m / s, 8 m / s, 9 m / s, and 10 m / s.

[0040] According to an embodiment of the present invention, the ratio of the flow rate of the amine solution of R(NH2)n to the flow rate of phosgene at the outlet of the feed port N1 is 1:1 to 6:1, exemplified by 1:1, 2:1, 3:1, 4:1, 5:1, and 6:1.

[0041] Amines with the general formula R(NH2)n are mixed with solvents (chlorobenzene or dichlorobenzene) and enter the jet reactor through port N1. Due to the change in the cross-section of the throat channel of the ejector, suction force is formed at the material inlets N2 and N3. The pressurized gaseous phosgene and reflux liquid are mixed with the amine mixture under the action of suction to carry out a preliminary reaction. The reactor controls a certain pressure to ensure that the reaction materials exist in the reaction system in a liquid state.

[0042] The purpose of installing the reflux line is to reduce the low reaction yield caused by local overheating. The circulating material is mixed with the reactor feed to reduce the risk of local overconcentration and local reactor overheating. The power of the reflux material comes from the change of the cross-section of the channel of the mixture of organic amine and solvent in the ejector, which forms a suction power at the inlet of the remaining materials.

[0043] Beneficial effects of the present invention:

[0044] At present, the reaction load of a single reactor used for the production of isocyanates is at the level of 10,000 tons, and there is uncertainty in the market demand for some isocyanate products. Therefore, the actual production of isocyanates is basically based on sales, and the shelf life of such products is short, which causes the intermittent production of the reaction system, and frequent start-up and shutdown bring greater hidden dangers to production safety. To solve this problem, some existing manufacturers reduce the production capacity of the reactor to match multiple reaction systems, which results in high cost of the device, many control points, and increased difficulty in subsequent production management. In view of this situation, the present invention adjusts the position of the nozzle outlet of the injection pipe from the feed port N1 by arranging an adjustment device at the end of the reaction chamber to change the cross-sectional area of ​​the logistics circulation, so as to change the flow rate of the material to ensure the suction capacity of the injector, and at the same time adjust the circulation volume to keep matching with the corresponding load. The structure of the jet reactor of the present invention can meet the load adjustment of different demand quantities, and does not affect the reaction effect of isocyanate, thereby solving the production troubles of isocyanate. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a schematic diagram of the structure of the adjustable phosgenation jet reactor of the present invention. DETAILED DESCRIPTION

[0046] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0047] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0048] Example 1

[0049] Reference Figure 1 A jet reactor comprises a reaction chamber and a feed port N1, a feed port N2, a feed port N3 and a discharge port N4 arranged on the reaction chamber, wherein: the end of the feed port N1 inside the reaction chamber extends beyond the central axis of the reaction chamber in the extension direction of the end of the feed port N1.

[0050]

Feed port N1

[0051] The end position of the feed port N1 inside the reaction chamber can be adjusted by a hand wheel.

[0052] The cross-sectional area of ​​the end of the feed port N1 inside the reaction chamber is smaller than the cross-sectional area of ​​the feed port N1 outside the reaction chamber.

[0053] The central axis of the end of the feed port N1 in the extension direction inside the reaction chamber coincides with the central axis of the reaction chamber in the same direction.

[0054] The feed port N1 includes a first same-diameter section, a first reduced-diameter section and a second same-diameter section, one end of the first reduced-diameter section is connected to the first same-diameter section, and the other end of the first reduced-diameter section is connected to the second same-diameter section; the first same-diameter section, the first reduced-diameter section and the second same-diameter section are integrally formed.

[0055] Each of the first section of equal diameter and the second section of equal diameter is cylindrical, and the diameter of the first section of equal diameter is larger than the diameter of the second section of equal diameter; the first section of reduced diameter is truncated cone, and the diameter of the first section of reduced diameter decreases from top to bottom. The first section of reduced diameter and the second section of equal diameter constitute the nozzle part of the injection pipe of the injection reactor, the ratio of the size diameter of the nozzle is 2-6, and the cone vertex angle of the nozzle is 20°-90°.

[0056] The distance between the starting point of the first equal diameter section and the starting point of the first reduced diameter section does not exceed 250 mm.

[0057] The distance between the starting point of the first uniform diameter section and the end point of the first reduced diameter section does not exceed 400 nm, and is 350 mm as an example.

[0058] The distance between the starting point of the first section with the same diameter and the end point of the second section with the same diameter shall not exceed 450 mm.

[0059] The end point of the second section of equal diameter is set at a distance of no more than 20 mm from the bottom of the reaction chamber.

[0060]

Feed port N2

[0061] The end of the feed port N2 inside the reaction chamber does not contact the portion of the feed port N1 inside the reaction chamber. Preferably, the end of the feed port N2 inside the reaction chamber does not exceed the central axis of the reaction chamber in the direction in which the end of the feed port N1 extends.

[0062]

Feed port N3

[0063] The end of the feed port N3 inside the reaction chamber does not contact the portion of the feed port N1 inside the reaction chamber. Preferably, the end of the feed port N3 inside the reaction chamber does not exceed the central axis of the reaction chamber in the direction in which the end of the feed port N1 extends.

[0064]

Discharge port N4

[0065] The discharge port N4 is arranged at the rear of the reaction chamber and does not contact the portion of the feed port N1 in the reaction chamber.

[0066]

Reaction chamber

[0067] The ratio of the cross-sectional area of ​​the end of the feed port N1 inside the reaction chamber to the cross-sectional area of ​​the reaction chamber is 1:1.

[0068] The pressure in the reaction chamber is -0.55MPa to -0.35MPa.

[0069] The average flow rate of the raw material liquid added from the feed port N1 into the reaction chamber is 5 to 60 m / s; the ratio of the flow rate of the raw material liquid at the outlet of the feed port N1 to the flow rate of the raw material at the outlet of the feed port N2 is 1:1 to 6:1; the average flow rate of the feed port N2 is 5 to 10 m / s.

[0070] Example 2

[0071] The production method of isocyanate comprises the following steps: in the jet reactor of embodiment 1, mixing hexamethylenediamine and chlorobenzene at a molar ratio of 1:6.25 to obtain a hexamethylenediamine solution, and the solution flows into the jet reactor from a feed port N1 pipe mouth, and the flow rate is about 30 m / s in the diameter change of the feed port N1 of the jet reactor; phosgene enters the ejector from the feed port N2 at a flow rate of 7 m / s; a reaction liquid containing hexamethylene diisocyanate (HDI) with a concentration of 12 wt% enters from the feed port N3 at a flow rate of 1.5 m / s; due to the jetting effect of the hexamethylenediamine raw material containing chlorobenzene solvent at the feed port N1, a negative pressure of about -0.45 MPa is generated in the reaction chamber. The diameter of the first same-diameter section of the feed port N1 is 80 mm, and the distance between the starting point of the first same-diameter section and the starting point of the first reduced-diameter section is 150 mm; the length of the first reduced-diameter section is 100 mm; the first reduced-diameter section and the second same-diameter section constitute the nozzle part of the injection pipe of the injection reactor, the ratio of the size diameter of the nozzle is 4, and the cone vertex angle of the nozzle is 35°; the second same-diameter section (throat) is A regulating valve is set on the feed port N3 to control the reflux rate, and the reflux rate of the reflux material is controlled to be 3.26m 3 / h is used to control the reaction temperature to 125°C and the concentration of ammonium salt (about 3%) to prevent coking and caking from causing blockage of the jet reactor. After the reaction is completed, the reaction mixture is sent to the separator from the discharge port N4 for gas-liquid separation. The liquid phase is sampled for chromatographic analysis, and the yield of isocyanate is 98% of the theoretical yield. (Wherein: yield = actual output of isocyanate / mass of isocyanate produced by reacting 100% of the mass of the feed R(NH2)n*100%).

[0072] Example 3

[0073] Compared with Example 2, the only difference is that the feed amount of hexamethylenediamine added through the feed port N1 is changed to 60% of that in Example 2, and the vacuum period generated by the ejector is maintained at a negative pressure of -0.45 MPa by adjusting the hand wheel. At the same time, the feed amount of phosgene introduced through the feed port N2 is adjusted to 60% of that in Example 2, and the reflux amount of the reflux cooling material through the feed port N3 is adjusted to 60% of that in Example 2. The experimental results show that the reaction is normal, and no abnormal conditions such as blockage occur. The separator material is taken for chromatographic analysis, and the yield of isocyanate is 98.05% of the theoretical yield.

[0074] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A jet reactor, characterized in that: The jet reactor comprises a reaction chamber and a feed port N1, a feed port N2, a feed port N3 and a discharge port N4 arranged on the reaction chamber, wherein: The feed port N1 is at an end portion inside the reaction chamber and extends beyond the central axis of the reaction chamber in the direction in which the end portion of the feed port N1 extends.

2. The jet reactor according to claim 1, characterized in that The end of the feed port N2 inside the reaction chamber does not contact the portion of the feed port N1 inside the reaction chamber. Preferably, the end of the feed port N2 inside the reaction chamber does not exceed the central axis of the reaction chamber in the direction in which the end of the feed port N1 extends. Preferably, the end of the feed port N3 inside the reaction chamber does not contact the portion of the feed port N1 inside the reaction chamber. Preferably, the end of the feed port N3 inside the reaction chamber does not exceed the central axis of the reaction chamber in the direction in which the end of the feed port N1 extends. Preferably, the end position of the feed port N1 inside the reaction chamber is adjustable. For example, the end position can be adjusted by a rotary drive device (such as a hand wheel). Preferably, the cross-sectional area of ​​the end of the feed port N1 inside the reaction chamber is smaller than the cross-sectional area of ​​the feed port N1 outside the reaction chamber. Preferably, a central axis of the feed port N1 in an extending direction of the end portion inside the reaction chamber coincides with a central axis of the reaction chamber in the same direction.

3. The jet reactor according to claim 1, characterized in that The feed port N1 includes a first same-diameter section, a first reduced-diameter section, and a second same-diameter section, one end of the first reduced-diameter section is connected to the first same-diameter section, and the other end of the first reduced-diameter section is connected to the second same-diameter section. Preferably, the first same-diameter section, the first reduced-diameter section and the second same-diameter section may be integrally formed. Preferably, each of the first section with the same diameter and the second section with the same diameter is cylindrical, and the diameter of the first section with the same diameter is greater than the diameter of the second section with the same diameter. Preferably, the first diameter-reduced section is in a truncated cone shape, and the diameter of the first diameter-reduced section decreases from top to bottom. Preferably, the first reduced diameter section and the second equal diameter section constitute the nozzle portion of the injection pipe of the injection reactor. Preferably, the ratio of the size to diameter of the nozzle is 2-6, and the cone vertex angle of the nozzle is 20°-90°. Preferably, the distance between the starting point of the first equal-diameter section and the starting point of the first reduced-diameter section is no more than 250 mm. Preferably, the distance between the starting point of the first equal-diameter section and the end point of the first reduced-diameter section is no more than 400 nm. Preferably, the distance between the starting point of the first section with the same diameter and the end point of the second section with the same diameter does not exceed 450 mm. Preferably, the end point of the second section of equal diameter is arranged at a distance of no more than 20 mm from the bottom of the reaction chamber.

4. The jet reactor according to any one of claims 1 to 3, characterized in that The ratio of the cross-sectional area of ​​the end of the feed port N1 inside the reaction chamber to the cross-sectional area of ​​the reaction chamber is (0.1-1):

1. Preferably, the discharge port N4 is disposed at the tail of the reaction chamber and does not contact the portion of the feed port N1 in the reaction chamber. Preferably, the pressure in the reaction chamber is -0.55 MPa to -0.35 MPa.

5. The jet reactor according to any one of claims 1 to 4, characterized in that The average flow rate of the raw material liquid added through the feed inlet N1 into the reaction chamber is 5-60 m / s. Preferably, the ratio of the flow rate of the raw material liquid at the outlet of the feed port N1 to the flow rate of the raw material at the outlet of the feed port N2 is 1:1 to 6:

1. Preferably, the average flow rate of the feed inlet N2 is 5 to 10 m / s.

6. The jet reactor according to any one of claims 1 to 5 is used for phosgenation reaction.

7. The use according to claim 6, characterized in that The jet reactor is used for preparing isocyanate by phosgenation reaction. Preferably, the isocyanate has a structure as shown in the following formula I: R(NCO)n Wherein: R is an aliphatic, alicyclic or aromatic hydrocarbon group having 1 to 15 carbon atoms, and n is an integer from 1 to 3.

8. The use according to claim 7, characterized in that The isocyanate is selected from any one of the following compounds: 1,4-butanediisocyanate, 1,6-hexanediisocyanate, 1,4-diisocyanatocyclohexane, isophoronediisocyanate, 4,4'-dicyclohexylmethanediisocyanate, triisocyanatononane or toluenediisocyanate.

9. A method for preparing isocyanate, characterized in that: The method comprises: in the jet reactor described in any one of claims 1 to 5, reacting an amine having the general formula R(NH2)n with phosgene in a reaction chamber, adjusting the end position of a feed port N1 inside the reaction chamber by an adjusting device, thereby changing the cross-sectional area of ​​material flow, and further changing the flow rate of the material.

10. The preparation method according to claim 9, characterized in that: The amine of R(NH2)n is selected from any one of the following compounds: 1,4-butanediamine, 1,6-hexanediamine, 1,4-diaminocyclohexane, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 4,4'-dicyclohexylmethanediamine, triaminononane, a 2,4- / 2,6-toluenediamine mixture with an isomer ratio of 80 / 20-65 / 35, or pure 2,4-toluenediamine. Preferably, the amine of R(NH2)n is added to the reactor in the form of a solution. For example, the solvent used in the amine solution of R(NH2)n is selected from chlorobenzene, toluene, xylene, o-dichlorobenzene or decalin. Preferably, the amine solution of R(NH2)n is added into the reactor from the feed port N1. Preferably, the average flow rate of the R(NH2)n amine solution is 10 to 50 m / s. Preferably, the phosgene is added into the reactor from the feed port N2. For example, the average flow rate of the phosgene is 5-10 m / s. Preferably, the ratio of the flow rate of the amine solution of R(NH2)n to the flow rate of phosgene at the outlet of the feed port N1 is 1:1 to 6:1.

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