Ethylbenzene oxidation reaction system

Abstract

The utility model provides an ethylbenzene oxidation reaction system. The system comprises a reactor, a plurality of partition plates are sequentially arranged in the reactor from top to bottom, and the multiple partition plates sequentially divide the reactor into at least three reaction areas from top to bottom; the uppermost reaction zone in the reactor is connected with a liquid inlet pipeline, and the side wall of the lowermost reaction zone in the reactor is provided with a product outlet; an airlift pipeline is vertically arranged on the upper surface of the partition plate; an overflow weir is arranged between every two adjacent reaction areas, the top of the overflow weir is lower than the liquid level of the upper reaction area, and the bottom of the overflow weir is a first preset distance away from the bottom of the lower reaction area; an enhanced mass transfer unit is arranged in each reaction zone, a gas inlet of the enhanced mass transfer unit is connected with a gas inlet pipeline for inputting a gas-phase raw material, and the gas-phase raw material enters the reaction zone after being treated by the enhanced mass transfer unit so as to enhance the mass transfer effect between the gas-phase raw material and the liquid-phase raw material. According to the scheme, the reaction efficiency of ethylbenzene peroxidation reaction can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of ethylbenzene oxidation reaction, in particular to an ethylbenzene oxidation reaction system. Background Art

[0002] The propylene oxide-styrene (PO / SM) co-production process, also known as the co-oxidation process, is an important chemical production technology. The PO / SM co-production process technology route mainly uses propylene and ethylbenzene as raw materials and adopts the co-oxidation process to produce propylene oxide and styrene product monomers. The process first directly oxidizes ethylbenzene with air or oxygen to produce ethylbenzene hydroperoxide (EBHP), and then EBHP and propylene undergo epoxidation reaction under the action of a molybdenum-based catalyst to produce methylbenzyl alcohol (phenylethanol) and propylene oxide. The epoxidation reaction liquid is distilled to obtain propylene oxide (PO) products, and phenylethanol is dehydrated at 260°C and normal pressure to produce styrene (SM) products.

[0003] In the related art, ethylbenzene peroxidation reaction is usually carried out in multiple (eg, two) non-catalytic, liquid-phase oxidation reactors connected in series. The concentration of EBHP in the reaction product obtained after passing through multiple oxidation reactors is usually only 8-10 wt %, and the reaction efficiency is low.

[0004] In view of this, the present utility model is proposed. Utility Model Content

[0005] The first purpose of the utility model is to provide an ethylbenzene oxidation reaction system, which has a small overall space occupation, low production cost, high reaction efficiency, and a high concentration of ethylbenzene hydrogen peroxide in the reaction product, which can meet the needs of downstream production.

[0006] The second purpose of the utility model is to provide an ethylbenzene oxidation reaction method, which adopts the above system to carry out ethylbenzene oxidation reaction, thereby improving the reaction efficiency and product yield of ethylbenzene peroxidation reaction.

[0007] In order to achieve the above-mentioned purpose of the utility model, the following technical solutions are adopted:

[0008] The utility model provides an ethylbenzene oxidation reaction system, comprising: a reactor, in which a plurality of partitions are sequentially arranged from top to bottom, and the plurality of partitions sequentially divide the reactor from top to bottom to form at least three reaction zones; the reaction zone located at the top of the reactor is connected with a liquid inlet pipeline for inputting liquid-phase raw materials, and the side wall of the reaction zone located at the bottom of the reactor is provided with a product outlet for outputting products; an air lift pipeline is vertically arranged on the upper surface of the partition, the inlet at the bottom of the air lift pipeline is connected with the reaction zone located at the bottom, and the outlet at the top of the air lift pipeline is higher than the liquid level in the reaction zone located at the top in the vertical direction; an overflow weir is arranged between two adjacent reaction zones, the top of the overflow weir is lower than the liquid level in the reaction zone located at the top, and the bottom of the overflow weir is at a first preset distance from the bottom of the reaction zone located at the bottom; each reaction zone is provided with an enhanced mass transfer unit, the air inlet of the enhanced mass transfer unit is connected with an air inlet pipeline for inputting gaseous raw materials, and the gaseous raw materials in the air inlet pipeline enter the reaction zone after being processed by the enhanced mass transfer unit, so as to enhance the mass transfer effect between the gaseous raw materials and the liquid raw materials.

[0009] Such scheme only needs to use one reactor, and the overall space occupation is small, and cost is low. Reactor is divided into multiple reaction zones from top to bottom, and reaction raw materials (i.e. ethylbenzene and oxygen) can react through multiple reaction zones successively, which is conducive to improving raw material conversion rate, and the material after the reaction of the previous reaction zone flows into the next reaction zone, which can effectively avoid liquid phase back mixing, thereby preventing the excessive concentration of EBHP in the product from affecting the generation of ethylbenzene peroxidation. In addition, this mode of dividing the reactor into multiple reaction zones helps to reduce the height of each reaction zone, which helps to avoid the generation of bubble aggregation. Meanwhile, the system is fed with gaseous raw materials in each reaction zone, which can ensure that the gaseous raw materials in the reaction zone are sufficient, thereby helping to improve the conversion rate and reaction yield of liquid-phase raw materials, and the gaseous raw materials are sent to the corresponding reaction zone after being processed by the enhanced mass transfer unit, thus, the gas-liquid contact area of ​​gaseous raw materials and liquid-phase raw materials can be improved, and the gas-liquid mass transfer efficiency can be improved, thereby improving reaction efficiency. In a word, the overall space occupation of the system of this scheme is small, the production cost is low, the reaction efficiency is high, and the concentration of ethylbenzene hydrogen peroxide in the reaction product is higher, which can meet the needs of downstream production.

[0010] Preferably, the enhanced mass transfer unit includes a first enhanced mass transfer reactor, a second enhanced mass transfer reactor and a circulation pipeline; the first enhanced mass transfer reactor is arranged below the liquid level of the reaction zone, and the first enhanced mass transfer reactor is connected to the air inlet pipeline; the second enhanced mass transfer reactor is arranged above the liquid level of the reaction zone, and the outlet of the second enhanced mass transfer reactor is connected to the first enhanced mass transfer reactor; the inlet of the circulation pipeline is connected to the reaction zone, and the outlet of the circulation pipeline is connected to the second enhanced mass transfer reactor, and the material in the reaction zone is transported to the second enhanced mass transfer reactor through the circulation pipeline.

[0011] The above scheme can form a hybrid enhanced mass transfer unit by setting the first enhanced mass transfer reactor, the second enhanced mass transfer reactor and the circulation pipeline in the reaction zone, which is helpful to improve the application effect of a single enhanced mass transfer reactor; on the one hand, a collision flow can be formed between the first enhanced mass transfer reactor and the second enhanced mass transfer reactor to further disperse and crush the bubbles; on the other hand, when the first enhanced mass transfer reactor is blocked, the bubble flow of the second enhanced mass transfer reactor can be used to flush the first enhanced mass transfer reactor to prevent blockage. And such a setting can also improve the fixing effect, and the pipeline between the first enhanced mass transfer reactor and the second enhanced mass transfer reactor can support the second enhanced mass transfer reactor. The space in the reactor itself is relatively narrow. If the enhanced mass transfer reactor is too dispersed, it will also affect the normal operation of the reactor. In addition, the overall structure also shortens the distance between each enhanced mass transfer reactor, strengthens the mutual cooperation ability between each component, and improves the dispersion and crushing effect after the bubbles broken by the micro interface collide and impact each other. In summary, this scheme can obtain an enhanced mass transfer unit with better enhanced mass transfer effect by combining the first enhanced mass transfer reactor with the second enhanced mass transfer reactor. The application of this enhanced mass transfer unit helps to further increase the gas-liquid contact area of ​​the material in the reaction zone, thereby further improving the reaction efficiency and raw material conversion rate.

[0012] Preferably, a heat exchanger is provided on the circulation pipeline, and the material in the circulation pipeline is transported to the second enhanced mass transfer reactor after heat exchange by the heat exchanger. In this scheme, the material in the circulation pipeline is transported to the second enhanced mass transfer reactor after heat exchange by the heat exchanger, and finally enters the reaction zone. Therefore, the heat exchanger can be used to control the temperature of the material in the circulation pipeline, thereby realizing the temperature control of the material in the reaction zone, and avoiding the drastic temperature fluctuation affecting the conversion rate and selectivity of the reaction.

[0013] Preferably, multiple layers of grids are staggered from top to bottom in the reaction zone, and the multiple layers of grids are located between the first enhanced mass transfer reactor and the liquid surface of the reaction zone. In this scheme, the grids are provided to help avoid back-mixing between the reacted materials above and the unreacted materials below in the reaction zone, thereby helping to ensure the selectivity of the reaction, improve the reaction efficiency and the yield of ethylbenzene hydroperoxide.

[0014] Preferably, the inlet of the circulation pipeline is located between the first enhanced mass transfer reactor and the liquid surface of the reaction zone in the vertical direction. In this scheme, the circulation pipeline can stir the material in the reaction zone by sucking the material between the first enhanced mass transfer reactor and the liquid surface of the reaction zone, which helps to evenly distribute the microbubbles in the reaction zone and avoid bubble aggregation, thereby helping to further improve the gas-liquid mass transfer efficiency.

[0015] Preferably, the positions of the enhanced mass transfer units in two adjacent reaction zones are different, wherein the position of the enhanced mass transfer unit is the position of the enhanced mass transfer unit in the corresponding reaction zone; preferably, the number of reaction zones is three, and the positions of the enhanced mass transfer units in the three reaction zones are all different. Such an arrangement helps to further improve the uniformity of microbubble distribution in the reaction zone, thereby helping to further improve the reaction efficiency.

[0016] Preferably, a feed baffle is provided in the uppermost reaction zone in the reactor, the top of the feed baffle is higher than the liquid level in the reaction zone, and the bottom is at a second preset distance from the bottom of the reaction zone; a liquid inlet channel is formed between the feed baffle and the side wall of the reaction zone, and the liquid inlet pipeline is connected to the liquid inlet channel. This solution helps to avoid mixing between the liquid raw material and the reacted material in the reaction zone, and helps to ensure that the reaction in the reaction zone proceeds in an orderly manner.

[0017] Preferably, a discharge baffle is provided in the reaction zone at the bottom of the reactor, the bottom of the discharge baffle is connected to the bottom of the reaction zone, the top is lower than the liquid level of the reaction zone, a discharge channel is formed between the discharge baffle and the side wall of the reaction zone, and the product outlet is connected to the discharge channel. The scheme of this embodiment can prevent the unreacted material at the bottom of the reaction zone at the bottom from being directly discharged from the product outlet by providing the discharge baffle, and helps to extend the reaction path, improve the reaction efficiency and the yield of ethylbenzene hydroperoxide.

[0018] Preferably, for each reaction zone in the reactor except for the top reaction zone, an overflow baffle is provided near the overflow weir in the reaction zone, and the top of the overflow baffle is lower than the liquid level in the reaction zone. This arrangement helps to mitigate the impact of the material in the overflow channel on the material in the reaction zone below, and avoids the mixing of the reacted material in the reaction zone with the pre-reacted material due to the impact, thereby helping to ensure that the reaction in the reaction zone proceeds in an orderly manner.

[0019] Those skilled in the art can understand that the enhanced mass transfer reactor adopted in the present invention has been embodied in the prior patents of the present invention, such as patents with application numbers CN201610641119.6, CN201610641251.7, CN201710766435.0, CN106187660, CN105903425A, CN109437390A, CN205833127U and CN207581700U. The prior patent CN201610641119.6 describes in detail the specific product structure and working principle of the micron bubble generator (i.e., bubble breaker). The application document states that "the micron bubble generator includes a main body and a secondary crushing member, a cavity is provided in the main body, an inlet connected to the cavity is provided on the main body, the first and second opposite ends of the cavity are open, wherein the cross-sectional area of ​​the cavity decreases from the middle of the cavity to the first and second ends of the cavity; the secondary crushing member is provided at at least one of the first and second ends of the cavity, a part of the secondary crushing member is provided in the cavity, and an annular channel is formed between the secondary crushing member and the through holes open at both ends of the cavity. The micron bubble generator also includes an air inlet pipe and a liquid inlet pipe." From the specific structure disclosed in the application document, it can be known that its specific working principle is: the liquid enters the micron bubble generator tangentially through the liquid inlet pipe, rotates at ultra-high speed and cuts the gas, so that the gas bubbles are broken into micron-level microbubbles, thereby increasing the mass transfer area between the liquid phase and the gas phase, and the micron bubble generator in the patent is a pneumatic bubble breaker.

[0020] In addition, the prior patent 201610641251.7 records that the primary bubble breaker has a circulating liquid inlet, a circulating gas inlet and a gas-liquid mixture outlet, and the secondary bubble breaker connects the feed port with the gas-liquid mixture outlet, indicating that the bubble breaker requires gas-liquid mixture to enter. In addition, it can be seen from the following figures that the primary bubble breaker mainly uses circulating liquid as power, so the primary bubble breaker actually belongs to a hydraulic enhanced reactor, and the secondary bubble breaker simultaneously passes the gas-liquid mixture into an elliptical rotating ball for rotation, thereby achieving bubble breaking during the rotation process, so the secondary bubble breaker actually belongs to a gas-liquid linkage type bubble breaker. In fact, whether it is a hydraulic bubble breaker or a gas-liquid linkage type bubble breaker, it is a specific form of a bubble breaker. However, the enhanced mass transfer reactor adopted by the utility model is not limited to the above-mentioned forms. The specific structure of the bubble breaker recorded in the prior patent is only one of the forms that can be adopted by the utility model.

[0021] In addition, the prior patent 201710766435.0 records that "the principle of the bubble breaker is a high-speed jet to achieve mutual collision of gases"; and the prior patent CN106187660 also has relevant records on the specific structure of the bubble breaker, see paragraphs

[0031] -

[0041] in the specification, and the drawings, which explain in detail the specific working principle of the bubble breaker S-2. The top of the bubble breaker is a liquid phase inlet, and the side is a gas phase inlet. The liquid phase coming in from the top provides suction power, thereby achieving the effect of crushing into ultrafine bubbles. It can also be seen in the drawings that the bubble breaker has a conical structure, and the diameter of the upper part is larger than the diameter of the lower part, so that the liquid phase can better provide suction power.

[0022] Since the bubble breaker was just developed in the early stage of the prior patent application, it was named micron bubble generator (CN201610641119.6) in the early stage. With the continuous technical improvement, it was renamed as bubble breaker in the later stage. Now the enhanced mass transfer reactor in the utility model is equivalent to the previous micron bubble generator, micro interface generator, etc., but the name is different. In summary, the enhanced mass transfer reactor of the utility model belongs to the prior art.

[0023] The utility model also provides an ethylbenzene oxidation reaction method, which adopts the above-mentioned system and comprises: breaking the gaseous raw material into micro-bubbles at the micron level through enhanced mass transfer, and then mixing it with the liquid raw material for oxidation reaction; wherein the gaseous raw material is air or oxygen, and the liquid raw material is ethylbenzene.

[0024] Compared with the prior art, the beneficial effects of the utility model are:

[0025] 1. The utility model only needs to use one reactor, which occupies a small space and has low cost.

[0026] 2. The utility model divides the reactor into multiple reaction zones from top to bottom, so that the reaction raw materials (i.e., ethylbenzene and oxygen) can react in multiple reaction zones in sequence, which is beneficial to improving the raw material conversion rate. The materials after the reaction in the previous reaction zone flow into the next reaction zone, which can effectively avoid liquid phase backmixing, thereby preventing the excessive concentration of EBHP in the product from affecting the occurrence of ethylbenzene peroxidation reaction.

[0027] 3. The method of dividing the reactor into multiple reaction zones in the utility model helps to reduce the height of each reaction zone and helps to avoid the occurrence of bubble aggregation.

[0028] 4. The utility model introduces gaseous raw materials into each reaction zone, which can ensure that the gaseous raw materials in the reaction zone are sufficient, thereby helping to improve the conversion rate of the liquid-phase raw materials and the reaction yield. The gas-phase raw materials are all processed by the enhanced mass transfer unit and then sent to the corresponding reaction zone. Therefore, the gas-liquid contact area between the gas-phase raw materials and the liquid-phase raw materials can be increased, the gas-liquid mass transfer efficiency can be improved, and thus the reaction efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limiting of the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0030] Figure 1 The schematic diagram of the ethylbenzene oxidation reaction system according to one embodiment of the utility model is shown, wherein: 1, reactor; 101, first reaction zone; 102, second reaction zone; 103, third reaction zone; 104, tail gas outlet; 2, grille; 3, overflow weir; 4, gas lift pipeline; 5, partition; 6, overflow baffle; 7, discharge baffle; 8, product outlet; 9, feed baffle; 10, liquid inlet pipeline; 11, circulation pipeline; 12, heat exchanger; 13, circulation pump; 14, air inlet pipeline; 15, second enhanced mass transfer reactor; 16, delivery pipeline; 17, first enhanced mass transfer reactor. DETAILED DESCRIPTION

[0031] The technical solution of the utility model will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but those skilled in the art will understand that the embodiments described below are part of the embodiments of the utility model, rather than all of the embodiments, and are only used to illustrate the utility model, and should not be considered as limiting the scope of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the utility model. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0032] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] As described above, in the related art, ethylbenzene peroxidation reaction is usually carried out in multiple (e.g., two) non-catalytic, liquid-phase series oxidation reactors, and the concentration of EBHP in the reaction product obtained after the multiple oxidation reactors is usually only 8-10wt%. On the one hand, this production system requires the use of multiple oxidation reactors, resulting in a large overall space occupation; on the other hand, the concentration of EBHP in the reaction product obtained by this production system is low, the reaction efficiency is low, and due to the low concentration of EBHP, it cannot be directly applied to the downstream (e.g., ethylbenzene hydroperoxide epoxidation reaction), and it is usually necessary to add a concentration device to further concentrate it, which further increases the production cost. In view of this, the utility model provides an ethylbenzene oxidation reaction system and method, which are described in detail below.

[0035] According to one aspect of the utility model, an ethylbenzene oxidation reaction system is provided. Figure 1 A schematic diagram of an ethylbenzene oxidation reaction system according to an embodiment of the present invention is shown. Figure 1As shown, the ethylbenzene oxidation reaction system comprises: a reactor 1, wherein a plurality of partitions 5 are sequentially arranged from top to bottom in the reactor 1, and the plurality of partitions 5 sequentially divide the reactor 1 from top to bottom into at least three reaction zones; the reaction zone located at the top of the reactor 1 is connected to a liquid inlet pipe 10 for inputting liquid raw materials, and the side wall of the reaction zone located at the bottom of the reactor 1 is provided with a product outlet 8 for outputting products; an air lift pipe 4 is vertically arranged on the upper surface of the partition 5, and the inlet at the bottom of the air lift pipe 4 is connected to the reaction zone located below, and the top of the air lift pipe 4 is connected to the reaction zone located below. The outlet is higher than the liquid level in the reaction zone above in the vertical direction; an overflow weir 3 is arranged between two adjacent reaction zones, the top of the overflow weir 3 is lower than the liquid level in the reaction zone above, and the bottom of the overflow weir 3 is at a first preset distance from the bottom of the reaction zone below; each reaction zone is provided with an enhanced mass transfer unit, and the air inlet of the enhanced mass transfer unit is connected to an air inlet pipe 14 for inputting gaseous raw materials. The gaseous raw materials in the air inlet pipe 14 enter the reaction zone after being processed by the enhanced mass transfer unit, so as to enhance the mass transfer effect between the gaseous raw materials and the liquid raw materials.

[0036] In the embodiment of the present invention, the gas phase raw material may be air or oxygen, and the liquid phase raw material may be ethylbenzene. Reactor 1 may be a bubble column reactor.

[0037] As described above, the plurality of partitions 5 can separate the reactor 1 from top to bottom to form at least three reaction zones. For ease of description, the at least three reaction zones can be referred to as the first reaction zone 101, the second reaction zone 102, ..., the Nth reaction zone from top to bottom, wherein N is a positive integer greater than or equal to 3. Figure 1 In the embodiment shown, there are two partitions 5, and the two partitions 5 separate the reactor 1 into three reaction zones, namely, the first reaction zone 101, the second reaction zone 102 and the third reaction zone 103. It can be understood that Figure 1 This is only an example and not a limitation of the present invention. The number of baffles 5 can be greater, and accordingly, the number of reaction zones can increase with the increase in the number of baffles 5. Those skilled in the art can adaptively adjust the number of reaction zones and baffles 5 according to actual needs, which will not be described in detail.

[0038] In the embodiment of the utility model, an air lift pipe 4 is provided on the upper surface of the partition 5. The air lift pipe 4 is used to transport the gas at the top of the lower reaction zone of the two adjacent reaction zones to the upper reaction zone, so that the unreacted oxygen in the lower reaction zone can enter the upper reaction zone to continue to participate in the reaction. At the same time, the air lift pipe 4 can realize the series connection of all reaction zones, and the tail gas generated in the lower reaction zone can also be discharged into the upper reaction zone through the air lift pipe 4, and finally discharged through the tail gas outlet 104 at the top of the reactor 1. For example, the tail gas generated in the second reaction zone 102 can be sent to the first reaction zone 101 through the air lift pipe 4 located in the first reaction zone 101, and discharged from the tail gas outlet 104 together with the tail gas generated in the first reaction zone 101.

[0039] As described above, an overflow weir 3 is provided between two adjacent reaction zones, the top of the overflow weir 3 is lower than the liquid level of the reaction zone located above, and the bottom of the overflow weir 3 is at a first preset distance from the bottom of the reaction zone located below. Thus, an overflow channel can be formed between the overflow weir 3 and the inner wall of the reactor 1, and the reaction product of the reaction zone located above one of the two adjacent reaction zones enters the reaction zone located below through the overflow channel. The first preset distance can be set according to actual needs to ensure that the material in the overflow channel can enter the reaction zone through the gap between the bottom of the overflow weir 3 and the bottom of the reaction zone located below. Still taking the first reaction zone 101 and the second reaction zone 102 as an example for explanation, the material obtained by the reaction in the first reaction zone 101 can overflow to the overflow channel through the top of the overflow weir 3, and enter the second reaction zone 102 along the overflow channel.

[0040] In the embodiment of the utility model, each reaction zone is provided with an enhanced mass transfer unit. Optionally, the enhanced mass transfer unit can be composed of at least one enhanced mass transfer reactor. When the reactor 1 is working, oxygen can be dispersed and broken into micro-bubbles of micron level by the enhanced mass transfer unit to increase the phase boundary mass transfer area between the gas phase raw material and the liquid phase raw material, thereby enhancing the mass transfer effect between the gas phase raw material and the liquid phase raw material.

[0041] by Figure 1 The working process of the reactor 1 is described as an example. Figure 1As shown, ethylbenzene enters the first reaction zone 101 through the liquid inlet pipe 10, and oxygen (or air) enters the first reaction zone 101 after being processed by the enhanced mass transfer unit in the first reaction zone 101, and is mixed with ethylbenzene to undergo an oxidation reaction to generate ethylbenzene hydroperoxide. The material obtained by the reaction in the first reaction zone 101 (including the generated ethylbenzene hydroperoxide and unreacted ethylbenzene) enters the second reaction zone 102 through the overflow weir 3, and oxygen (or air) enters the second reaction zone 102 after being processed by the enhanced mass transfer unit in the second reaction zone 102, and is mixed with ethylbenzene in the material transported by the first reaction zone 101 to undergo an oxidation reaction to generate ethylbenzene hydroperoxide. The materials obtained by the reaction in the second reaction zone 102 (including the generated ethylbenzene hydroperoxide and the unreacted ethylbenzene) enter the third reaction zone 103 through the overflow weir 3, and the oxygen (which may also be air) enters the third reaction zone 103 after being processed by the enhanced mass transfer unit in the third reaction zone 103, and is mixed with the ethylbenzene in the materials transported from the second reaction zone 102 to undergo an oxidation reaction to generate ethylbenzene hydroperoxide. The materials obtained by the reaction in the third reaction zone 103 are discharged through the product outlet 8.

[0042] The utility model person finds through research that the reaction of ethylbenzene oxidation to generate hydrogen peroxide has the characteristics of slow reaction rate, temperature sensitivity, large product concentration influence, medium reaction heat effect, etc., thus, the reactor of this reaction should meet the requirements such as large liquid holdup, high heat transfer efficiency, stable operation, easy control of reaction conditions, etc. However, the utility model person further finds that the liquid phase backmixing in the reactor (such as bubble column reactor) that can meet the large liquid holdup is serious and the ethylbenzene peroxidation reaction is very sensitive to the concentration of product EBHP, and the liquid phase backmixing will reduce the selectivity of the reaction, and is also unfavorable for the control of the reaction. In addition, when the reactor height-diameter ratio is large, there will be the aggregation of bubbles, and the bubble dispersion effect is deteriorated, so that the gas-liquid contact area is reduced, and the gas-liquid mass transfer efficiency is affected. In view of the above-mentioned research, the embodiment of the utility model provides a kind of ethylbenzene oxidation reaction system, and this reaction system only needs to use a reactor, and the overall occupied space is small, and the cost is low. The reactor is divided into multiple reaction zones from top to bottom, and reaction raw materials (i.e. ethylbenzene and oxygen) can react successively through multiple reaction zones, which is conducive to improving raw material conversion, and the material after the reaction of the previous reaction zone flows into the next reaction zone, which can effectively avoid liquid phase back mixing, thereby preventing the excessive concentration of EBHP in the product from affecting the generation of ethylbenzene peroxidation. In addition, this mode of dividing the reactor into multiple reaction zones helps to reduce the height of each reaction zone, which helps to avoid the generation of bubble aggregation. Meanwhile, the system is passed through gaseous raw materials in each reaction zone, which can ensure that the gaseous raw materials in the reaction zone are sufficient, thereby helping to improve the conversion rate and reaction yield of liquid-phase raw materials, and the gaseous raw materials are sent into the corresponding reaction zone after being processed by the enhanced mass transfer unit, thus, the gas-liquid contact area of ​​gaseous raw materials and liquid-phase raw materials can be improved, and the gas-liquid mass transfer efficiency can be improved, thereby improving reaction efficiency. In a word, the overall system footprint of the scheme is small, the production cost is low, the reaction efficiency is high, and the concentration of ethylbenzene hydrogen peroxide in the reaction product is higher, which can meet the needs of downstream production.

[0043] Preferably, if Figure 1 As shown, the enhanced mass transfer unit includes a first enhanced mass transfer reactor 17, a second enhanced mass transfer reactor 15 and a circulation pipeline 11; the first enhanced mass transfer reactor 17 is arranged below the liquid level of the reaction zone, and the first enhanced mass transfer reactor 17 is connected to the air inlet pipeline 14; the second enhanced mass transfer reactor 15 is arranged above the liquid level of the reaction zone, and the outlet of the second enhanced mass transfer reactor 15 is connected to the first enhanced mass transfer reactor 17; the inlet of the circulation pipeline 11 is connected to the reaction zone, and the outlet of the circulation pipeline 11 is connected to the second enhanced mass transfer reactor 15, and the material in the reaction zone is transported to the second enhanced mass transfer reactor 15 through the circulation pipeline 11.

[0044] In this article, the enhanced mass transfer reactor can be any one of a pneumatic enhanced mass transfer reactor, a hydraulic enhanced mass transfer reactor, and a gas-liquid coupled enhanced mass transfer reactor. Figure 1In the illustrated embodiment, the first enhanced mass transfer reactor 17 is a pneumatic enhanced mass transfer reactor, and the second enhanced mass transfer reactor 15 is a hydraulic enhanced mass transfer reactor.

[0045] Optionally, a circulation pump 13 may be provided on the circulation pipeline 11 .

[0046] As described above, the outlet of the second intensified mass transfer reactor 15 is connected to the first intensified mass transfer reactor 17. Figure 1 In the illustrated embodiment, the outlet of the second enhanced mass transfer reactor 15 is connected to the first enhanced mass transfer reactor 17 via a delivery pipe 16. The microbubble flow outputted from the second enhanced mass transfer reactor 15 enters the first enhanced mass transfer reactor 17 through the delivery pipe 16, and is discharged from the outlet of the first enhanced mass transfer reactor 17 together with the microbubble flow in the first enhanced mass transfer reactor 17.

[0047] Optionally, the outlet of the first enhanced mass transfer reactor 17 can be arranged on the side wall or the top of the first enhanced mass transfer reactor 17. In this case, the power for transporting the microbubble flow outward comes from the first enhanced mass transfer reactor 17 and the second enhanced mass transfer reactor 15, thereby increasing the flow energy of the microbubble flow, impacting the material at the outlet of the first enhanced mass transfer reactor 17, and preventing the microbubbles from coalescing at the outlet of the first enhanced mass transfer reactor 17.

[0048] In the scheme of this embodiment, the circulation pipeline 11 can extract the liquid in the reaction zone and transport it to the second enhanced mass transfer reactor 15. On the one hand, the circulation pipeline 11 can stir the material in the reaction zone during the circulation of the material, which helps to evenly distribute the microbubbles in the reaction zone and avoid bubble aggregation, thereby helping to further improve the gas-liquid mass transfer efficiency. On the other hand, after the material in the circulation pipeline 11 enters the second enhanced mass transfer reactor 15, the second enhanced mass transfer reactor 15 can be used to further disperse and crush the material to form microbubbles, further increasing the gas-liquid contact area.

[0049] According to the above preferred embodiment, by arranging the first enhanced mass transfer reactor 17, the second enhanced mass transfer reactor 15 and the circulation pipeline 11 in the reaction zone, a hybrid enhanced mass transfer unit can be formed, which is helpful to improve the application effect of a single enhanced mass transfer reactor; on the one hand, a collision flow can be formed between the first enhanced mass transfer reactor 17 and the second enhanced mass transfer reactor 15 to further disperse and crush the bubbles; on the other hand, when the first enhanced mass transfer reactor 17 is blocked, the bubble flow of the second enhanced mass transfer reactor 15 can be used to flush the first enhanced mass transfer reactor 17 to prevent blockage. And such an arrangement can also improve the fixing effect, and the pipeline between the first enhanced mass transfer reactor 17 and the second enhanced mass transfer reactor 15 plays a supporting effect on the second enhanced mass transfer reactor 15. The space in the reactor itself is relatively narrow. If the enhanced mass transfer reactor is too dispersed, it will also affect the normal operation of the reactor. In addition, the overall structure also shortens the distance between each enhanced mass transfer reactor, strengthens the mutual cooperation ability between each component, and improves the dispersion and crushing effect after the bubbles broken by the micro interface collide and impact each other. In summary, this scheme can obtain an enhanced mass transfer unit with better enhanced mass transfer effect by combining the first enhanced mass transfer reactor 17 and the second enhanced mass transfer reactor 15. The application of this enhanced mass transfer unit helps to further increase the gas-liquid contact area of ​​the material in the reaction zone, thereby further improving the reaction efficiency and raw material conversion rate.

[0050] Preferably, if Figure 1 As shown, a heat exchanger 12 is provided on the circulation pipeline 11 , and the material in the circulation pipeline 11 is transported to the second enhanced mass transfer reactor 15 after heat exchange in the heat exchanger 12 .

[0051] In such Figure 1 In the illustrated embodiment, the circulation pump 13 is disposed behind the heat exchanger 12 along the material flow direction in the circulation pipeline 11 , thereby helping to reduce the circulation resistance of the circulation pump 13 .

[0052] In this preferred technical solution, the material in the circulation pipeline 11 is transported to the second enhanced mass transfer reactor 15 after heat exchange in the heat exchanger 12, and finally enters the reaction zone. Therefore, the heat exchanger 12 can be used to control the temperature of the material in the circulation pipeline 11, thereby achieving temperature control of the material in the reaction zone and avoiding drastic temperature fluctuations that affect the conversion rate and selectivity of the reaction.

[0053] Preferably, if Figure 1 As shown, the reaction zone is staggered with multi-layered grids 2 from top to bottom, and the multi-layered grids 2 are located between the first enhanced mass transfer reactor 17 and the liquid surface of the reaction zone. In this scheme, the grids 2 are provided to help avoid the back-mixing between the reacted materials above and the unreacted materials below in the reaction zone, thereby helping to ensure the selectivity of the reaction, improve the reaction efficiency and the yield of ethylbenzene hydroperoxide.

[0054] Preferably, if Figure 1 As shown, the inlet of the circulation pipeline 11 is located between the first enhanced mass transfer reactor 17 and the liquid surface of the reaction zone in the vertical direction. Therefore, the circulation pipeline 11 can play a stirring role on the material in the reaction zone by sucking the material between the first enhanced mass transfer reactor 17 and the liquid surface of the reaction zone, which helps to evenly distribute the microbubbles in the reaction zone and avoid bubble aggregation, thereby helping to further improve the gas-liquid mass transfer efficiency.

[0055] Preferably, the positions of the enhanced mass transfer units in two adjacent reaction zones are different, wherein the position of the enhanced mass transfer unit is the position of the enhanced mass transfer unit in the corresponding reaction zone. Figure 1 As shown, there are three reaction zones, and the positions of the enhanced mass transfer units in the three reaction zones are all different. This arrangement helps to further improve the uniformity of microbubble distribution in the reaction zones, thereby helping to further improve the reaction efficiency.

[0056] Preferably, a feed baffle 9 is provided in the uppermost reaction zone of the reactor 1, the top of the feed baffle 9 is higher than the liquid level in the reaction zone, and the bottom is at a second preset distance from the bottom of the reaction zone; a liquid inlet channel is formed between the feed baffle 9 and the side wall of the reaction zone, and the liquid inlet pipe 10 is connected to the liquid inlet channel. The second preset distance can be set according to actual needs and will not be described in detail.

[0057] by Figure 1 For example, in this preferred embodiment, the liquid phase material enters the first reaction zone 101 from the bottom of the first reaction zone 101 along the liquid inlet channel to participate in the reaction. Thus, it is prevented from mixing with the reacted material in the first reaction zone 101, which helps to ensure that the reaction in the first reaction zone 101 proceeds in an orderly manner.

[0058] Preferably, if Figure 1 As shown, the reaction zone at the bottom of the reactor 1 (at Figure 1 In the embodiment, the reaction zone is the third reaction zone 103) in which a discharge baffle 7 is provided, the bottom of the discharge baffle 7 is connected to the bottom of the reaction zone, the top is lower than the liquid level of the reaction zone, a discharge channel is formed between the discharge baffle 7 and the side wall of the reaction zone, and the product outlet 8 is connected to the discharge channel. In this embodiment, the product after the reaction in the third reaction zone 103 overflows into the discharge channel through the discharge baffle 7 and is discharged from the product outlet 8. The scheme of this embodiment can avoid the direct discharge of the unreacted material at the bottom of the third reaction zone 103 from the product outlet 8 by providing the discharge baffle 7, and helps to extend the reaction path, improve the reaction efficiency and the yield of ethylbenzene hydrogen peroxide.

[0059] Preferably, if Figure 1As shown, for each reaction zone in the reactor 1 except the top reaction zone, an overflow baffle 6 is provided near the overflow weir 3 in the reaction zone, and the top of the overflow baffle 6 is lower than the liquid level in the reaction zone. Taking the second reaction zone 102 as an example, in the second reaction zone 102, the inner wall of the reactor 1, the overflow weir 3, and the overflow baffle 6 form a "U"-shaped channel, and the material obtained by the reaction in the first reaction zone 101 enters the second reaction zone 102 through the "U"-shaped channel. This arrangement helps to mitigate the impact of the material in the overflow channel on the material in the reaction zone below, and avoids the mixing of the reacted material in the reaction zone with the pre-reacted material due to the impact, thereby helping to ensure that the reaction in the reaction zone proceeds in an orderly manner.

[0060] According to another aspect of the utility model, an ethylbenzene oxidation reaction method is provided, which adopts the system of any of the above embodiments, and the method comprises: breaking the gaseous raw material into micro-bubbles of micron level by enhanced mass transfer, and then mixing with the liquid raw material for oxidation reaction; wherein the gaseous raw material is air or oxygen, and the liquid raw material is ethylbenzene. In a specific embodiment, the gaseous raw material is air.

[0061] In order to more clearly explain the technical solution of the present invention, it is described in the form of specific embodiments below.

[0062] Example 1

[0063] This embodiment adopts Figure 1 The system shown produces ethylbenzene hydroperoxide. The gas phase raw material is air, the liquid phase raw material is ethylbenzene, the reaction temperature in the reactor is 145°C, and the pressure is 0.24MPa. After testing, the concentration of ethylbenzene hydroperoxide in the reaction product (i.e., the material discharged from the product outlet) is 48wt%.

[0064] Example 2

[0065] The difference between this embodiment and embodiment 1 is that the first enhanced mass transfer reactor and the second enhanced mass transfer reactor in the enhanced mass transfer unit are not connected, and the outlet of the second enhanced mass transfer reactor is arranged below the liquid surface. After testing, the concentration of ethylbenzene hydroperoxide in the reaction product (i.e., the material discharged from the product outlet) is 43wt%.

[0066] By comparing Example 1 and Example 2, it can be seen that the concentration of ethylbenzene hydroperoxide in the reaction product in Example 1 is significantly higher than that in Example 2. It can be seen that the technical solution of Example 1 can improve the application effect of a single enhanced mass transfer reactor by connecting two enhanced mass transfer reactors, further improve the dispersion and crushing effect of the material, thereby improving the reaction efficiency and product yield.

[0067] Example 3

[0068] The difference between this embodiment and embodiment 1 is that the enhanced mass transfer unit does not include a circulation pipeline, and the inlet of the second enhanced mass transfer reactor is connected to the liquid inlet channel. After testing, the concentration of ethylbenzene hydroperoxide in the reaction product (i.e., the material discharged from the product outlet) is 45wt%.

[0069] Comparing Example 1 and Example 3, it can be seen that the concentration of ethylbenzene hydroperoxide in the reaction product in Example 1 is significantly higher than that in Example 3. This may be because the circulation pipeline can not only transport materials to the second enhanced mass transfer reactor, but also stir the materials in the reaction zone to prevent bubbles from agglomerating and affecting the gas-liquid mass transfer efficiency.

[0070] Example 4

[0071] The only difference between this embodiment and embodiment 1 is that no heat exchanger is provided on the circulation pipeline. According to detection, the concentration of ethylbenzene hydroperoxide in the reaction product (ie, the material discharged from the product outlet) is 38 wt %.

[0072] Comparing Example 1 and Example 4, it can be seen that the concentration of ethylbenzene hydroperoxide in the reaction product in Example 1 is significantly higher than that in Example 4. This may be due to the fact that the exothermic reaction in Example 4 causes a more drastic temperature fluctuation in the reaction zone, which affects the conversion rate and selectivity of the reaction. It can be seen that the scheme of Example 1 can achieve temperature control of the material in the reaction zone by arranging a heat exchanger on the circulation pipeline, thereby avoiding the drastic temperature fluctuation affecting the conversion rate and selectivity of the reaction.

[0073] Example 5

[0074] The only difference between this embodiment and embodiment 1 is that no barrier is provided. According to detection, the concentration of ethylbenzene hydroperoxide in the reaction product (ie, the material discharged from the product outlet) is 43 wt %.

[0075] Comparing Example 1 and Example 5, it can be seen that the concentration of ethylbenzene hydroperoxide in the reaction product in Example 1 is significantly higher than that in Example 5. This may be because Example 1 reduces liquid phase backmixing by setting a barrier, avoids the occurrence of ethylbenzene peroxidation reaction inhibited by excessively high concentration of ethylbenzene hydroperoxide in the product, thereby improving the reaction efficiency and product yield.

[0076] Example 6

[0077] The only difference between this embodiment and embodiment 1 is that the positions of the enhanced mass transfer units in the multiple reaction zones are the same. According to the test, the concentration of ethylbenzene hydroperoxide in the reaction product (ie, the material discharged from the product outlet) is 45 wt%.

[0078] By comparing Example 1 and Example 6, it can be seen that the concentration of ethylbenzene hydroperoxide in the reaction product in Example 1 is significantly higher than that in Example 6. This may be because the uniformity of the microbubble distribution in Example 6 is lower than that in Example 1. It can be seen that in Example 1, by making the positions of the enhanced mass transfer units in the two adjacent reaction zones different, it is helpful to improve the uniformity of the microbubble distribution in the reaction zone, thereby helping to further increase the gas-liquid contact area and improve the reaction efficiency.

[0079] Comparative Example 1

[0080] The only difference between this embodiment and embodiment 1 is that no enhanced mass transfer unit is provided in the reaction zone. According to detection, the concentration of ethylbenzene hydroperoxide in the reaction product (i.e., the material discharged from the product outlet) is 18 wt %.

[0081] Comparing Examples 1-6 with Comparative Example 1, it can be seen that the concentrations of ethylbenzene hydroperoxide in the reaction products of Examples 1-6 are significantly higher than those of Comparative Example 1. It can be seen that the solution of the utility model significantly improves the reaction efficiency and product yield by arranging an enhanced mass transfer unit in the reaction zone.

[0082] Comparative Example 2

[0083] The reaction temperature, pressure and reaction raw materials of this embodiment are the same as those of embodiment 1. In this embodiment, two non-catalytic, liquid-phase oxidation reactors connected in series are used as reactors for the ethylbenzene peroxidation reaction. According to the test, the concentration of ethylbenzene hydroperoxide in the reaction product obtained by the reaction is 9wt%.

[0084] Comparative Example 2 is a solution adopted in the related art. Comparing Examples 1-6 with Comparative Example 2, it can be seen that the concentration of ethylbenzene hydroperoxide in the reaction product in Examples 1-6 is significantly higher than that in Comparative Example 2. This shows that the system of the utility model can significantly improve the reaction efficiency and product yield of the ethylbenzene peroxidation reaction, and the concentration of ethylbenzene hydroperoxide in Examples 1-6 basically meets the requirements of the downstream epoxidation reaction (i.e., the concentration of ethylbenzene hydroperoxide in the product reaches about 40wt%). Therefore, when the system of the utility model is applied to the PO / SM co-production process, there is no need to set a concentration unit to further concentrate the product, and the reaction product of the reactor can be directly sent to the epoxidation reactor, which can reduce the occupied area of ​​the production system adopted by the PO / SM co-production process and reduce production costs.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. An ethylbenzene oxidation reaction system, characterized in that: include: A reactor, wherein a plurality of partitions are sequentially arranged from top to bottom in the reactor, and the plurality of partitions sequentially divide the reactor from top to bottom into at least three reaction zones; the reaction zone located at the top of the reactor is connected to a liquid inlet pipeline for inputting liquid raw materials, and the side wall of the reaction zone located at the bottom of the reactor is provided with a product outlet for outputting products; An air lift pipe is vertically arranged on the upper surface of the partition, the inlet at the bottom of the air lift pipe is connected to the reaction zone located below, and the outlet at the top of the air lift pipe is higher than the liquid level in the reaction zone located above in the vertical direction; An overflow weir is arranged between two adjacent reaction zones, the top of the overflow weir is lower than the liquid level of the reaction zone located above, and the bottom of the overflow weir is at a first preset distance from the bottom of the reaction zone located below; An enhanced mass transfer unit is provided in each of the reaction zones, and an air inlet of the enhanced mass transfer unit is connected to an air inlet pipeline for inputting gaseous raw materials. The gaseous raw materials in the air inlet pipeline enter the reaction zone after being processed by the enhanced mass transfer unit, so as to enhance the mass transfer effect between the gaseous raw materials and the liquid raw materials.

2. The system according to claim 1, characterized in that The enhanced mass transfer unit comprises a first enhanced mass transfer reactor, a second enhanced mass transfer reactor and a circulation pipeline; The first enhanced mass transfer reactor is disposed below the liquid surface of the reaction zone, and the first enhanced mass transfer reactor is connected to the air inlet pipeline; The second enhanced mass transfer reactor is disposed above the liquid level of the reaction zone, and the outlet of the second enhanced mass transfer reactor is connected to the first enhanced mass transfer reactor; The inlet of the circulation pipeline is connected to the reaction zone, the outlet of the circulation pipeline is connected to the second enhanced mass transfer reactor, and the material in the reaction zone is transported to the second enhanced mass transfer reactor through the circulation pipeline.

3. The system according to claim 2, characterized in that The circulation pipeline is provided with a heat exchanger, and the material in the circulation pipeline is transported to the second enhanced mass transfer reactor after heat exchange by the heat exchanger.

4. The system according to claim 2, characterized in that Multiple layers of grids are staggered from top to bottom in the reaction zone, and the multiple layers of grids are located between the first enhanced mass transfer reactor and the liquid surface of the reaction zone.

5. The system according to claim 2, characterized in that The inlet of the circulation pipeline is located between the first enhanced mass transfer reactor and the liquid surface of the reaction zone in the vertical direction.

6. The system according to any one of claims 1 to 4, characterized in that: The positions of the enhanced mass transfer units in two adjacent reaction zones are different, wherein the position of the enhanced mass transfer unit is the position of the enhanced mass transfer unit in the corresponding reaction zone.

7. The system according to claim 6, characterized in that The number of the reaction zones is three, and the positions of the enhanced mass transfer units in the three reaction zones are different.

8. The system according to any one of claims 1 to 4, characterized in that: A feed baffle is provided in the uppermost reaction zone of the reactor, wherein the top of the feed baffle is higher than the liquid level in the reaction zone, and the bottom of the feed baffle is at a second preset distance from the bottom of the reaction zone; a liquid inlet channel is formed between the feed baffle and the side wall of the reaction zone, and the liquid inlet pipe is connected to the liquid inlet channel.

9. The system according to any one of claims 1 to 4, characterized in that: A discharge baffle is provided in the reaction zone at the bottom of the reactor, the bottom of the discharge baffle is connected to the bottom of the reaction zone, and the top is lower than the liquid level of the reaction zone. A discharge channel is formed between the discharge baffle and the side wall of the reaction zone, and the product outlet is connected to the discharge channel.

10. The system according to any one of claims 1 to 4, characterized in that: For each reaction zone in the reactor except the reaction zone located at the top, an overflow baffle is arranged in the reaction zone near the overflow weir, and the top of the overflow baffle is lower than the liquid level of the reaction zone.

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