A continuous production method and continuous production system of isopropanolamine

Abstract

The present invention provides a continuous production method and continuous production system of isopropanolamine. The scheme of the present invention is adopted to improve the yield and reaction conversion rate of monoisopropanolamine, and the required reaction equipment is simple, the floor space is small, and the equipment investment is small. The continuous production method comprises the following steps: 1) continuously feeding the reaction mass including water, liquid ammonia and propylene oxide into a loop reactor, wherein the reaction mass circulates in the loop reactor and performs a first stage reaction; 2) continuously extracting part of the reaction liquid in the loop reactor into a kettle reactor to continue the second stage reaction, and obtaining a reaction product containing monoisopropanolamine; wherein, an internal hollow spoiler is provided in the inner cavity of the loop reactor, and the spoiler is in an overall expanded diameter structure along the material flow direction in the inner cavity of the loop reactor, and the outer shell of the spoiler is formed with a hollow portion arranged in multiple layers.

Description

Technical Field

[0001] The invention relates to the technical field of isopropanolamine production, and in particular to a continuous production method and a continuous production system of isopropanolamine. Background Art

[0002] Isopropanolamine (IPA) is an important organic intermediate, including three products: monoisopropanolamine, diisopropanolamine, and triisopropanolamine. Monoisopropanolamine can be used as a surfactant, textile auxiliaries, pharmaceutical / pesticide intermediates, dispersants, dye auxiliaries, metal cutting fluids, etc. Diisopropanolamine can be used as a gas desulfurizer, decontaminant, pharmaceutical / pesticide intermediate, etc. Triisopropanolamine can be used as a cement grinding aid, rubber, and a crosslinking agent for processing polyurethane. Among the three products, triisopropanolamine has the largest output, a low production threshold, relatively fierce competition, and the lowest profit margin. Monoisopropanolamine has a high production threshold, is widely used, has a tight supply, and has the highest profit margin. The reaction uses ammonia and propylene oxide as raw materials and water as a catalyst to generate monoisopropanolamine, diisopropanolamine, and triisopropanolamine, which is a three-stage cascade reaction. Regulating the feed ratio of ammonia and propylene oxide can change the proportion of the products. The more ammonia, the greater the proportion of monoisopropanolamine, and vice versa. However, excess ammonia will increase the size of the reactor, increase the energy consumption of the separation cycle, and increase operating costs.

[0003]

[0004] Reducing the degree of back-mixing of the reaction solution can effectively reduce the generation of triisopropanolamine. In theory, the use of tubular reactors and packed towers can suppress back-mixing. Patent application CN1410416A reports the use of multi-stage tubular reactors for the production of isopropanolamine. However, with the increase in production capacity, the length of the tubular reactor will reach several thousand meters, the reactor investment is huge, and the flow pressure drop in the tube is also large. Patent application CN105348118A reports that packed towers are used for the production of isopropanolamine, but the heat exchange area of ​​the packed tower is relatively small, the heat exchange capacity is insufficient, and it is not suitable for such highly exothermic reactions, and the flow pressure drop and fluid distribution of the packed tower also require special consideration. Summary of the invention

[0005] In view of this, the present invention provides a continuous production method and a continuous production system of isopropanolamine. The scheme of the present invention is beneficial to improving the yield and reaction conversion rate of monoisopropanolamine, and the required reaction equipment is simple, the floor space is small, and the equipment investment is small.

[0006] To achieve the purpose, the present invention provides the following technical solutions:

[0007] One aspect of the present invention provides a method for continuously producing isopropanolamine, comprising the steps of:

[0008] 1) continuously feeding reaction materials including water, liquid ammonia and propylene oxide into a loop reactor, wherein the reaction materials circulate in the loop reactor and perform a first stage reaction;

[0009] 2) continuously extracting part of the reaction liquid in the loop reactor into a tank reactor to continue the second stage reaction, thereby obtaining a reaction product containing monoisopropanolamine;

[0010] Among them, a hollow spoiler is provided in the inner cavity of the annular tube reactor. Along the material flow direction in the inner cavity of the annular tube reactor, the spoiler is an overall expanded diameter structure, and the outer shell of the spoiler is formed with multiple layers of hollow parts arranged at intervals.

[0011] In a preferred embodiment, in the loop reactor of step 1), the reaction conditions of the first stage reaction include: a residence time of 30-80 min (e.g., 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, etc.), preferably 30-60 min, a reaction temperature of 120-160 ° C (e.g., 120 ° C, 130 ° C, 140 ° C, 150 ° C, 160 ° C, etc.), for example, 120-150 ° C, preferably 130-150 ° C, an operating pressure of 8-15 MPa; in the autoclave reactor of step 2), the reaction conditions of the second stage reaction include: residence time of 30-80min (e.g., 30min, 40min, 50min, 60min, 70min, 80min, etc.), preferably 30-60min, reaction temperature of 120-160°C (e.g., 120°C, 130°C, 140°C, 150°C, 160°C, etc.), for example, 120-150°C, preferably 130-150°C, operating pressure of 8-15MPa. The preferred combination of reaction conditions is used in the first stage reaction and the second stage reaction, which is conducive to further improving the conversion rate and the yield of monoisopropanolamine.

[0012] In the method of the present invention, the feed ratio between the reaction materials can adopt the conventional ratio in the art, and there is no particular restriction on this. In a preferred embodiment, the molar ratio of the liquid ammonia to the propylene oxide is 5:1-30:1, preferably 8:1-20:1. The preferred molar ratio is advantageous for obtaining a better reaction conversion rate and monoisopropanolamine yield, and will not cause a substantial increase in downstream separation energy consumption and a larger volume requirement for the reaction equipment; the amount of water used is 0.5%-5% of the mass of the liquid ammonia.

[0013] In a preferred embodiment, in step 2), the ratio of the mass flow rate of the reaction liquid extracted from the loop reactor to the mass flow rate of the reaction liquid circulating in the loop reactor is 1:5-30, preferably 1:10-30.

[0014] In some embodiments, in the outer shell of the spoiler, the hollowed-out portions of each layer are annular or substantially annular. Preferably, the outer shell of the spoiler is spiral-shaped; or, the outer shell includes a plurality of annular rings arranged at intervals.

[0015] In a preferred embodiment, the cross-sectional void ratio of the spoiler is 0.6-0.8.

[0016] In some embodiments, the loop reactor is provided with an outer jacket for regulating the reaction temperature in the loop reactor;

[0017] The tank reactor is provided with an inner coil for regulating the reaction temperature in the loop reactor.

[0018] In a preferred embodiment, the stirring paddle provided in the kettle reactor is an upturned axial flow paddle. Preferably, the blade diameter of the upturned axial flow paddle is 1 / 3-1 / 2 of the diameter of the kettle body of the kettle reactor.

[0019] The present invention also provides a continuous production system of isopropanolamine, which is particularly suitable for implementing the continuous production method described above. The continuous production system comprises a loop reactor and a kettle reactor;

[0020] The loop reactor is used to circulate the reaction materials including water, liquid ammonia and propylene oxide which are continuously introduced therein and perform the first stage reaction;

[0021] The kettle reactor is connected to the loop reactor through a withdrawal pipe for receiving part of the reaction liquid withdrawn from the loop reactor and allowing it to continue the second stage reaction to obtain a reaction product containing monoisopropanolamine;

[0022] The inner cavity of the annular tube reactor is provided with an internal hollow spoiler. Along the material flow direction in the inner cavity of the annular tube reactor, the spoiler is an overall expanded diameter structure, and the outer shell of the spoiler is formed with multiple layers of hollow parts arranged at intervals.

[0023] In some embodiments, in the outer shell of the spoiler, the hollow portions of each layer are annular or substantially annular; preferably, the outer shell of the spoiler is spiral; or, the outer shell includes a plurality of annular rings arranged at intervals.

[0024] In a preferred embodiment, the cross-sectional void ratio of the spoiler is 0.6-0.8.

[0025] In a preferred embodiment, the stirring paddle provided in the kettle reactor is an upturned axial flow paddle, and the blade diameter of the upturned axial flow paddle is 1 / 3-1 / 2 of the diameter of the kettle body of the kettle reactor.

[0026] In a preferred embodiment, an axial flow pump is provided in the annular tube reactor.

[0027] The technical solution provided by the present invention has the following beneficial effects:

[0028] The invention adopts a serially connected loop reactor and a kettle reactor, wherein the reaction material first circulates in the loop reactor and performs a first-stage reaction, and then a part of the reaction liquid is taken out and sent to the kettle reactor to continue the second-stage reaction, and a spoiler with a specific structure is arranged in the loop reactor. The scheme of the invention is adopted to continuously prepare isopropanolamine, and a higher reaction conversion rate and monoisopropanolamine yield can be obtained.

[0029] The scheme of the present invention is adopted to continuously prepare isopropanolamine, and the required equipment has a simple structure, a small volume, a small footprint, and a small equipment investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of a continuous production system of isopropanolamine in one embodiment;

[0031] Figure 2 is a partial schematic diagram of a flow disruptor disposed in a loop reactor in one embodiment;

[0032] Figure 3 FIG. 1 is a schematic diagram of the structure of a tank reactor in one embodiment. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the invention belongs. The term "and / or" as may be used herein includes any and all combinations of one or more of the associated listed items.

[0035] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in the art can be used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased commercially.

[0036] The present invention provides a continuous production method of isopropanolamine, which mainly comprises the following steps:

[0037] 1) continuously feeding reaction materials including water, liquid ammonia and propylene oxide into a loop reactor 1, wherein the reaction materials circulate in the loop reactor 1 and undergo a first stage reaction;

[0038] 2) continuously extracting part of the reaction liquid in the loop reactor 1 to the kettle reactor 2 to continue the second stage reaction, thereby obtaining a reaction product containing monoisopropanolamine; and the reaction liquid in the loop reactor 1 that has not been extracted continues to circulate in the loop reactor 1;

[0039] Among them, a hollow spoiler 5 is provided in the inner cavity of the annular tube reactor 1. Along the material flow direction in the inner cavity of the annular tube reactor 1, the spoiler 5 is an overall expanded diameter structure, and the outer shell of the spoiler 5 is formed with multiple layers of hollow parts 15 arranged at intervals.

[0040] Adopt the loop reactor 1 and the kettle reactor 2 connected in series, set the hollow shell and the internal hollow spoiler 5 in the loop reactor 1, and the spoiler 5 is an overall expansion structure along the material flow direction in the inner cavity of the loop reactor 1; the reaction material is reacted in the first stage in the loop reactor 1 provided with the spoiler 5 of a specific structure and circulated therein, and part of the reaction solution is extracted to the kettle reactor 2 for the second stage reaction; the isopropanolamine is continuously prepared in this way, and a higher reaction conversion rate and a higher monoisopropanolamine yield can be taken into account. And the required equipment structure is simple, the operation process is concise, the equipment covers a small area, and the equipment investment is small.

[0041] Preferably, in the loop reactor 1 of step 1), the reaction conditions of the first stage reaction include: residence time of 30-80min, preferably 30-60min, reaction temperature of 120-160°C, preferably 130-150°C, and operating pressure of 8-15MPa; in the kettle reactor 2 of step 2), the reaction conditions of the second stage reaction include: residence time of 30-80min, preferably 30-60min, reaction temperature of 120-160°C, preferably 130-150°C, and operating pressure of 8-15MPa. Adopting the preferred reaction conditions to carry out step 1) and step 2) is conducive to obtaining better reaction effect, and is conducive to further improving the reaction conversion rate and the yield of monoisopropanolamine. Preferably, the residence time of the first stage reaction and the second stage reaction is 30-60min, and under the same process conditions, it can take into account higher production capacity, good conversion rate and monoisopropanol yield. Preferably, the reaction temperatures of the first reaction stage and the second reaction stage are both 130-150° C., which is beneficial for achieving both a higher reaction conversion rate and a higher yield of monoisopropanolamine under the same process conditions.

[0042] In the present invention, the dosage of each component in the reaction material, such as liquid ammonia, propylene oxide and water, can adopt the conventional feeding ratio in the art, and there is no particular restriction on this. Preferably, the molar ratio of liquid ammonia to propylene oxide is 5:1-30:1, and the amount of water is 0.5%-5% of the mass of liquid ammonia. The molar ratio of liquid ammonia to propylene oxide is more preferably 8:1-20:1, which is conducive to taking into account good reaction conversion rate and high monoisopropanolamine yield under the same reaction conditions, and will not cause a significant increase in downstream separation energy consumption and reaction equipment volume.

[0043] In a preferred embodiment, in step 2), the ratio of the mass flow rate of the reaction liquid extracted from the loop reactor 1 to the mass flow rate of the reaction liquid circulating in the loop reactor 1 (referred to as the extraction / circulation ratio) is 1:5-30, preferably 1:10-30; adopting the preferred extraction / circulation ratio can achieve a better mixing effect between the materials in the loop reactor 1 and is conducive to maintaining low pump power consumption.

[0044] The present invention sets a spoiler 5 of a specific structure in the loop reactor 1, and makes the material flow from the narrow end of the spoiler 5 to the wide end as a whole when flowing through the spoiler 5, and the outer shell of the spoiler 5 is hollowed out, and the inside of the spoiler 5 is hollow; by setting such a spoiler 5, the flow boundary layer of the circulating liquid flow of the loop reactor 1 can be effectively broken, turbulence is generated, which is conducive to improving the reaction conversion rate and the yield of monoisopropanolamine, and has a smaller pressure drop. In some embodiments, in the outer shell of the spoiler 5, each layer of the hollow portion 15 is annular or roughly annular. In some embodiments, the outer shell of the spoiler 5 is spiral, specifically, along the material flow direction in the inner cavity of the loop reactor 1, the outer contour of the spiral outer shell is an expanded diameter structure as a whole, and the gap on the spiral line of the spiral outer shell is formed as the hollow portion 15. In some embodiments, the outer shell includes a plurality of annular rings 13 arranged at intervals, and these annular rings 13 can be fixed to each other by one or more pillars 14, and the gap between the annular rings 13 is the hollow portion 15. The spoiler 5 can be made of metal. In some embodiments, the cross section of the spoiler 5 along its axial direction is conical or substantially conical as a whole. Specifically, a plurality of spoilers 5 can be arranged at intervals in the annular reactor 1, and the flow pressure drop is small.

[0045] Preferably, the cross-sectional voidage of the spoiler 5 is 0.6-0.8, and the cross-sectional voidage refers to: in the projection of the spoiler in the flow direction of the fluid in the loop reactor, the ratio of the projection area corresponding to the hollow portion and the cross-sectional area of ​​the tube body cavity of the loop reactor (i.e., the cross-sectional area along the radial direction of the loop reactor). Using a spoiler 5 with a cross-sectional voidage of 0.6-0.8, low flow resistance can be maintained, and a good material mixing effect is obtained; compared to a spoiler with a lower cross-sectional voidage, the monoisopropanolamine yield can be significantly improved.

[0046] In some embodiments, the loop reactor 1 is provided with an outer jacket 4 for regulating the reaction temperature in the loop reactor 1. Specifically, a heat exchange medium, such as thermal oil, can be circulated in the outer jacket 4. The present invention adopts a loop reactor 1 and a kettle reactor 2 connected in series, which has a high volumetric yield and is not prone to temperature runaway. The kettle reactor 2 is provided with an inner coil 10 for regulating the reaction temperature in the kettle reactor 2. Specifically, a heat exchange medium, such as thermal oil, can be circulated in the inner coil 10; the specific arrangement form of the inner coil 10 can adopt the conventional arrangement method in the art, for example, it can be spirally arranged or serpentinely arranged in the kettle body of the kettle reactor 2, and a support plate 16 can be set in the inner cavity of the kettle reactor 2 to fix the inner coil 10.

[0047] Better, see Figure 3 The stirring paddle provided in the tank reactor 2 is an upturned axial flow paddle. Preferably, the blade diameter of the upturned axial flow paddle is 1 / 3-1 / 2 of the diameter of the tank body 8 of the tank reactor 2, which is conducive to obtaining a better material mixing effect and material distribution in the tank reactor 2. In some embodiments, the height / diameter ratio of the tank body 8 of the tank reactor 2 is 1-1.5.

[0048] The present invention also provides a continuous production system capable of implementing the continuous production method of isopropanolamine described above. Figure 1-3The continuous production system mainly includes a loop reactor 1 and a tank reactor 2. The loop reactor 1 is used for the first stage reaction. Specifically, the loop reactor 1 can receive the reaction materials including water, liquid ammonia and propylene oxide continuously introduced therein, and make these reaction materials circulate in the loop reactor 1 and undergo the first stage reaction. Specifically, an axial flow pump 3 is provided in the loop reactor 1, and the axial flow pump 3 is used to promote the materials in the loop reactor 1 to circulate therein; the axial flow pump 3 can be installed in a pipeline at the bottom of the loop reactor 1, for example. The tank reactor 2 is connected to the loop reactor 1 through a withdrawal pipe 7. Specifically, the loop reactor 1 is provided with a withdrawal port, and the tank reactor 2 is provided with a feed port 18. The withdrawal pipe 7 is connected between the withdrawal port of the loop reactor 1 and the feed port 18 of the tank reactor 2. The tank reactor 2 is used to receive the reaction liquid withdrawn from the withdrawal port of the loop reactor 1 and continue the second stage reaction to obtain a reaction product containing monoisopropanolamine. Further, an internal hollow spoiler 5 is provided in the inner cavity of the loop reactor 1, and along the material flow direction in the inner cavity of the loop reactor 1 (i.e., the circulating flow direction of the material in the inner cavity of the loop reactor 1), the spoiler 5 is an overall expanded diameter structure, and the shell of the spoiler 5 is formed with a multi-layer spaced hollow portion 15. Adopting the loop reactor 1 and the kettle reactor 2 connected in series, and arranging the spoiler 5 of a specific structure in the loop reactor 1, it is possible to reduce pressure drop, improve the degree of material mixing, reduce material back mixing, and help improve reaction conversion rate and monoisopropanolamine yield.

[0049] Further, in the outer shell of the spoiler 5, each layer of the hollow portion 15 is annular or substantially annular. In some embodiments, the outer shell of the spoiler 5 is spiral, and the number of spiral turns is, for example, but not limited to, 10-20; specifically, along the material flow direction in the inner cavity of the annular tube reactor 1, the outer contour of the spiral shell is an expanded diameter structure as a whole, and the gap on the spiral line of the spiral shell is the hollow portion 15. In some embodiments, the shell includes a plurality of annular rings 13 arranged at intervals, and the number of annular rings 13 is, for example, but not limited to, 10-20, and these annular rings 13 can be fixed to each other by one or more pillars 14; along the material flow direction in the inner cavity of the annular tube reactor 1, each annular ring 13 is arranged in sequence and the diameter is gradually increasing, and the gap between the annular rings 13 is the hollow portion 15. The spoiler 5 can be made of metal, and the spoiler 5 can be fixed in the annular tube reactor 1 by snapping.

[0050] In a preferred embodiment, the cross-sectional void ratio of the spoiler 5 is 0.6-0.8, such as 0.6, 0.65, 0.7, 0.75, 0.8, etc.

[0051] In a preferred embodiment, the stirring paddle provided in the kettle reactor 2 is an upturned axial flow paddle 9 , and the blade diameter of the upturned axial flow paddle is 1 / 3-1 / 2 of the diameter of the kettle body 8 of the kettle reactor 2 .

[0052] In the present invention, the diameter of the tube body of the loop reactor 1 is not particularly limited, and may be, for example, 100-500 mm.

[0053] Unless otherwise specified, the loop reactor and the tank reactor are conventional structures in the art and will not be described in detail. Figure 3 For example, the kettle body of the kettle reactor is also specifically provided with a feed inlet 18, a thermometer socket 19, a pressure gauge detection port 20, a safety valve 21, a discharge port 17, etc.

[0054] In order to better illustrate the present invention and facilitate understanding of the technical solution of the present invention, the following is further described by examples, but it does not mean that the present invention is limited to the following examples. Product analysis method: Use gas chromatography to analyze the mass fractions of propylene oxide, monoisopropanolamine, diisopropanolamine, and triisopropanolamine in the reaction liquid extracted from the autoclave reactor, and calculate the conversion rate of propylene oxide.

[0055] Gas chromatography detection conditions: Shimadzu GC-2010PLUS; chromatographic column: DB-5MS (60m×0.25mm×0.25um); vaporization chamber temperature: 270°C; programmed temperature conditions: initial temperature 40°C, hold for 3min, heat to 300°C at 15°C / min, hold for 11min; detector temperature: 300°C; carrier gas: high-purity nitrogen (purity 99.999%); column flow rate: 1-1.5ml / min; analysis method: normalization.

[0056] The conversion rate is defined as: 100% - (mass of propylene oxide remaining in the reaction solution / mass of propylene oxide in the initial feed * 100%); the mass fraction of each isopropanolamine is defined as: the mass of the corresponding isopropanolamine in the reaction solution * 100% / the total mass of the reaction solution. The yield of monoisopropanolamine is measured by its mass fraction in the reaction solution.

[0057] Example 1

[0058] This embodiment provides a continuous production method for preparing isopropanolamine. The continuous production system used is as follows: Figure 1 As shown, the loop reactor 1 and the tank reactor 2 are connected in series via a withdrawal pipe 7; for the specific description of the continuous production system, please refer to the above description, which will not be repeated here.

[0059] The spoiler 5 installed in the loop reactor 1 is as follows: Figure 2As shown, the spoiler 5 is formed by a plurality of annular rings 13 arranged at intervals, and the cross-sectional porosity of the spoiler 5 is 0.65; heat transfer oil is introduced into the outer jacket 4 of the loop reactor 1 to control the reaction temperature in the loop reactor 1. The stirring paddle used in the kettle reactor 2 is an upturned axial flow paddle; the paddle diameter of the upturned axial flow paddle is 1 / 2 of the diameter of the kettle body 8 of the kettle reactor 2; heat transfer oil is introduced into the inner coil 10 provided in the kettle body 8 of the kettle reactor 2 to control the reaction temperature in the kettle reactor 2. In the feed of the loop reactor 1, the molar ratio of liquid ammonia to propylene oxide is 10:1, and the total feed amount of each raw material is 0.65m 3 / h, the amount of water (as a catalyst) added is 3% of the mass of liquid ammonia in the feed. Before feeding, the temperature of each raw material is preheated to about 110°C. The reaction pressures of loop reactor 1 and tank reactor 2 are maintained at about 10MPa respectively. The residence time of loop reactor 1 and tank reactor 2 is controlled at about 50min; the reaction temperature is controlled at about 140°C. During the reaction process, the ratio of the mass flow rate of the reaction liquid extracted from loop reactor 1 to the mass flow rate of the reaction liquid circulating in loop reactor 1 is 1:6.

[0060] Experimental results: The reaction liquid taken out from the outlet of the autoclave reactor 2 was analyzed and calculated, wherein the conversion rate of propylene oxide reached 97.3%, the mass fraction of monoisopropanolamine accounted for 18.8wt% of the reaction liquid, the mass fraction of diisopropanolamine accounted for 7.6wt% of the reaction liquid, and the mass fraction of triisopropanolamine accounted for 2.1wt% of the reaction liquid.

[0061] Example 2

[0062] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0063] The residence time of the loop reactor 1 and the tank reactor 2 is controlled at about 80 min.

[0064] Experimental results: The conversion rate of propylene oxide reached 98.0%, monoisopropanolamine accounted for 18.5wt% of the reaction liquid, diisopropanolamine accounted for 8.1wt% of the reaction liquid, and triisopropanolamine accounted for 2.5wt%.

[0065] Compared with Example 1, the residence time of the two reactors in this example is prolonged, and the reaction results are almost the same, indicating that a residence time of more than 60 min has no beneficial effect on the reaction, but will reduce the production capacity.

[0066] Example 3

[0067] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0068] The residence time of the loop reactor 1 and the tank reactor 2 is controlled at about 30 minutes. Experimental results: The conversion rate of propylene oxide reaches 92.0%, monoisopropanolamine accounts for 15.5wt% of the reaction solution, diisopropanolamine accounts for 6.2wt% of the reaction solution, and triisopropanolamine accounts for 2.0wt%.

[0069] Compared with Example 1, the residence time of the two reactors in this example is shortened, the reaction conversion rate is slightly reduced, and the yield of monoisopropanolamine is slightly reduced, but still within the range acceptable to the process.

[0070] Example 4

[0071] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0072] The reaction temperature of the loop reactor 1 and the tank reactor 2 was 120°C.

[0073] Experimental results: The conversion rate of propylene oxide reached 90.3%, monoisopropanolamine accounted for 13.8wt% of the reaction liquid, diisopropanolamine accounted for 5.6wt% of the reaction liquid, and triisopropanolamine accounted for 1.5wt%.

[0074] Compared with Example 1, the reaction temperatures of the two reactors in this example are lowered, the reaction conversion rate decreases, and the yield of monoisopropanolamine decreases.

[0075] Example 5

[0076] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0077] The reaction temperature of the loop reactor 1 and the tank reactor 2 was 160°C.

[0078] Experimental results: The conversion rate of propylene oxide reached 100%, monoisopropanolamine accounted for 10.2wt% of the reaction liquid, diisopropanolamine accounted for 9.0wt% of the reaction liquid, and triisopropanolamine accounted for 5.5wt%.

[0079] Compared with Example 1, the reaction temperatures of the two reactors in this example are increased, and the reaction results are as follows: the reaction conversion rate is increased, but the yield of monoisopropanolamine is reduced, and the heating energy consumption of the reaction at a higher temperature is greater.

[0080] Example 6

[0081] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0082] The molar ratio of liquid ammonia to propylene oxide fed into loop reactor 1 was 5:1.

[0083] Experimental results: The conversion rate of propylene oxide reached 96.6%, monoisopropanolamine accounted for 12.5wt% of the reaction liquid, diisopropanolamine accounted for 10.8wt% of the reaction liquid, and triisopropanolamine accounted for 8.7wt%.

[0084] Compared with Example 1, the conversion rate is slightly lowered and the yield of monoisopropanolamine is reduced.

[0085] Example 7

[0086] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0087] The molar ratio of liquid ammonia to propylene oxide fed into loop reactor 1 was 30:1.

[0088] Experimental results: The conversion rate of propylene oxide reached 99.8%, monoisopropanolamine accounted for 22.3wt% of the reaction liquid, diisopropanolamine accounted for 6.5wt% of the reaction liquid, and triisopropanolamine accounted for 1.4wt%.

[0089] Compared with Example 1, the reaction conversion rate and the yield of monoisopropanolamine are both improved, but excessive liquid ammonia feed will increase the separation energy consumption and the equipment volume.

[0090] Example 8

[0091] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0092] The ratio of the mass flow rate of the reaction liquid extracted from the loop reactor 1 to the mass flow rate of the reaction liquid circulating in the loop reactor 1 is 1:5.

[0093] Experimental results: The conversion rate of propylene oxide reached 97.0%, monoisopropanolamine accounted for 18.4wt% of the reaction liquid, diisopropanolamine accounted for 7.9wt% of the reaction liquid, and triisopropanolamine accounted for 2.4wt%.

[0094] Compared with Example 1, the reaction results did not change significantly, the conversion rate was slightly reduced, and the yield of monoisopropanolamine was slightly reduced.

[0095] Example 9

[0096] This embodiment is carried out with reference to Embodiment 1, and only the differences are described below:

[0097] The ratio of the mass flow rate of the reaction liquid extracted from the loop reactor 1 to the mass flow rate of the reaction liquid circulating in the loop reactor 1 is 1:30.

[0098] Experimental results: The conversion rate of propylene oxide reached 97.9%, monoisopropanolamine accounted for 18.9wt% of the reaction liquid, diisopropanolamine accounted for 7.4wt% of the reaction liquid, and triisopropanolamine accounted for 2.0wt%.

[0099] Compared with Example 1, the reaction results were almost unchanged, but the larger circulation volume increased the energy consumption of the pump.

[0100] Comparative Example 1

[0101] This comparative example is carried out with reference to Example 1, and the similarities are not repeated here, and only the differences are described below: the spoiler 5 is not installed in the loop reactor 1; the residence time of the loop reactor 1 and the kettle reactor 2 is 80 min.

[0102] Experimental results: The reaction liquid taken out from the outlet of the autoclave reactor 2 was analyzed and calculated, wherein the conversion rate of propylene oxide at the outlet of the autoclave reactor 2 was 84.2%, monoisopropanolamine accounted for 11.3wt% of the reaction liquid, diisopropanolamine accounted for 8.8wt% of the reaction liquid, and triisopropanolamine accounted for 3.4wt% of the reaction liquid.

[0103] Compared with Example 1, the comparative example does not install the spoiler 5 in the loop reactor 1. As a result, the reaction is carried out at a longer residence time, but the conversion rate and the yield of monoisopropanolamine comparable to those of Example 1 are still not achieved, and the yield of the target product is greatly reduced, and the reaction conversion rate is also greatly reduced. Compared with Example 2 with the same residence time, the conversion rate and the yield of monoisopropanolamine are also significantly reduced.

[0104] Comparative Example 2

[0105] This comparative example is carried out with reference to Example 1, and the similarities are not repeated here, and only the differences are described below: the loop reactor 1 is not connected to the kettle reactor 2.

[0106] Experimental results: The reaction liquid taken out from the outlet of loop reactor 1 was analyzed and calculated, wherein the conversion rate of propylene oxide at the outlet of loop reactor 1 was 73.6%, monoisopropanolamine accounted for 8.1wt% of the reaction liquid, diisopropanolamine accounted for 6.2wt% of the reaction liquid, and triisopropanolamine accounted for 1.6wt% of the reaction liquid.

[0107] Compared with Example 1, this comparative example only used the loop reactor 1, and as a result, the conversion rate and the yield level of monoisopropanolamine comparable to those of Example 1 could not be achieved.

[0108] Comparative Example 3

[0109] This comparative example is carried out with reference to Example 1, and the similarities are not repeated here, and only the differences are described below: the loop reactor 1 is not used before the kettle reactor 2.

[0110] Experimental results: The reaction liquid taken out from the outlet of the autoclave reactor 2 was analyzed and calculated, wherein the conversion rate of propylene oxide at the outlet of the autoclave reactor 2 was 72.1%, monoisopropanolamine accounted for 7.6wt% of the reaction liquid, diisopropanolamine accounted for 5.8wt% of the reaction liquid, and triisopropanolamine accounted for 1.1wt% of the reaction liquid.

[0111] Compared with Example 1, this comparative example only used the autoclave reactor 2, and as a result, the conversion rate and the yield level of monoisopropanolamine comparable to those of Example 1 could not be achieved.

[0112] Comparative Example 4

[0113] This comparative example is carried out with reference to Example 1, and the similarities are not repeated here, and only the differences are described below: the porosity of the spoiler 5 installed in the loop reactor 1 is 0.4.

[0114] Experimental results: The reaction liquid taken out from the outlet of the autoclave reactor 2 was analyzed and calculated, wherein the conversion rate of propylene oxide at the outlet of the autoclave reactor 2 was 97.8%, monoisopropanolamine accounted for 7.8wt% of the reaction liquid, diisopropanolamine accounted for 7.7wt% of the reaction liquid, and triisopropanolamine accounted for 2.0wt% of the reaction liquid.

[0115] Compared with Example 1, the porosity of the spoiler 5 used in this comparative example becomes smaller, and the conversion rate decreases slightly, but the yield of monoisopropanolamine decreases significantly. Moreover, during the reaction process, the use of the spoiler with a smaller porosity increases the flow pressure drop in the annular tube, which increases the power consumption of the pump.

[0116] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A continuous production method of isopropanolamine, characterized in that, The steps include: 1) continuously feeding reaction materials including water, liquid ammonia and propylene oxide into a loop reactor, wherein the reaction materials circulate in the loop reactor and perform a first stage reaction; the reaction conditions of the first stage reaction include: a residence time of 30-80 min, a reaction temperature of 120-160° C., and an operating pressure of 8-15 MPa; a molar ratio of the liquid ammonia to the propylene oxide of 5:1-30:1, and an amount of water of 0.5%-5% of the mass of the liquid ammonia; 2) continuously extracting part of the reaction liquid in the loop reactor to the kettle reactor to continue the second stage reaction to obtain a reaction product containing monoisopropanolamine; the reaction conditions of the second stage reaction include: a residence time of 30-80 min, a reaction temperature of 120-160° C., and an operating pressure of 8-15 MPa; The inner cavity of the loop reactor is provided with a hollow spoiler. Along the material flow direction in the inner cavity of the loop reactor, the spoiler is an expanded diameter structure as a whole, and the outer shell of the spoiler is formed with multiple layers of hollow parts arranged at intervals; the cross-sectional porosity of the spoiler is 0.6-0.8; The cross-sectional porosity refers to the ratio of the projection area corresponding to the hollow portion in the projection of the flow spoiler in the flow direction of the fluid in the loop reactor to the cross-sectional area of ​​the inner cavity of the tube body of the loop reactor; In step 2), the ratio of the mass flow rate of the reaction liquid extracted from the loop reactor to the mass flow rate of the reaction liquid circulating in the loop reactor is 1:5-30.

2. The continuous production method according to claim 1, characterized in that: In the loop reactor of step 1), the reaction conditions of the first stage reaction include: residence time of 30-60 min, reaction temperature of 130-150° C.; In the autoclave reactor of step 2), the reaction conditions of the second stage reaction include: a residence time of 30-60 min and a reaction temperature of 130-150°C.

3. The continuous production method according to claim 1, characterized in that: The molar ratio of the liquid ammonia to the propylene oxide is 8:1-20:

1.

4. The continuous production method according to any one of claims 1 to 3, characterized in that: In step 2), the ratio of the mass flow rate of the reaction liquid extracted from the loop reactor to the mass flow rate of the reaction liquid circulating in the loop reactor is 1:10-30.

5. The continuous production method according to any one of claims 1 to 3, characterized in that: In the outer shell of the spoiler, each layer of the hollowed-out portion is ring-shaped.

6. The continuous production method according to claim 5, characterized in that: The outer shell of the spoiler is spiral-shaped; or, the outer shell includes a plurality of annular rings arranged at intervals.

7. The continuous production method according to any one of claims 1 to 3, characterized in that: The loop reactor is provided with an outer jacket for regulating the reaction temperature in the loop reactor; The tank reactor is provided with an inner coil for regulating the reaction temperature in the tank reactor.

8. The continuous production method according to any one of claims 1 to 3, characterized in that: The stirring paddle arranged in the kettle reactor is an upward-turned axial flow paddle.

9. The continuous production method according to claim 8, characterized in that: The blade diameter of the upward-turned axial-flow impeller is 1 / 3-1 / 2 of the diameter of the kettle body of the kettle reactor.

10. A continuous production system of isopropanolamine, characterized in that: The continuous production system includes a loop reactor and a tank reactor; The loop reactor is used to circulate the reaction materials including water, liquid ammonia and propylene oxide which are continuously introduced therein and perform the first stage reaction; The kettle reactor is connected to the loop reactor through a withdrawal pipe for receiving part of the reaction liquid withdrawn from the loop reactor and allowing it to continue the second stage reaction to obtain a reaction product containing monoisopropanolamine; A hollow spoiler is provided in the inner cavity of the loop reactor. Along the material flow direction in the inner cavity of the loop reactor, the spoiler is in an expanded diameter structure as a whole, and the outer shell of the spoiler is formed with multiple layers of hollow parts arranged at intervals; The cross-sectional void ratio of the spoiler is 0.6-0.8; The cross-sectional porosity refers to the ratio of the projection area corresponding to the hollow portion in the projection of the spoiler in the flow direction of the fluid in the loop reactor to the cross-sectional area of ​​the inner cavity of the tube body of the loop reactor.

11. The continuous production system according to claim 10, characterized in that: In the outer shell of the spoiler, the hollowed-out portions of each layer are ring-shaped; And / or, the stirring paddle provided in the kettle reactor is an upturned axial flow paddle, and the blade diameter of the upturned axial flow paddle is 1 / 3-1 / 2 of the diameter of the kettle body of the kettle reactor; And / or, an axial flow pump is provided in the annular tube reactor.

12. The continuous production system according to claim 11, characterized in that: The outer shell of the spoiler is spiral-shaped, or the outer shell includes a plurality of annular rings arranged at intervals.

13. The continuous production system according to any one of claims 10 to 12, characterized in that: The continuous production system is used to implement the continuous production method according to any one of claims 1 to 9.

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