Continuous synthesis process and device of alkenyl succinic anhydride

Abstract

The invention relates to the technical field of alkenyl succinic anhydride synthesis, in particular to a continuous synthesis process and device for alkenyl succinic anhydride, and the continuous synthesis process at least comprises the following steps: filling a fixed bed reactor with an immobilized AlCl3 catalyst; a mixed material obtained after preheating of maleic anhydride and internal olefin enters a fixed bed reactor, the mixed material makes contact with an immobilized AlCl3 catalyst and is subjected to a catalytic reaction to synthesize a crude product, the crude product is cooled, olefin is separated and recycled through distillation, and the alkenyl succinic anhydride product is obtained after filtration. Compared with a traditional production technology, continuous production is achieved, the technological process is simple, safety is higher, and the production cost is low. Meanwhile, the energy consumption and the equipment investment cost are effectively reduced, and large-scale industrial application production is easy to realize.

Description

Technical Field

[0001] The invention relates to the technical field of alkenyl succinic anhydride synthesis, in particular to a continuous synthesis process and device of alkenyl succinic anhydride. Background Art

[0002] Alkenyl succinic anhydride (ASA) is an oily, viscous amber liquid at room temperature. It is synthesized from unsaturated internal olefins and maleic anhydride, and contains two hydrophobic groups and a reactive anhydride group in its molecular structure. Alkenyl succinic anhydride products mainly include dodecenyl succinic anhydride (DDSA), hexadecenyl succinic anhydride (HDSA), and octadecenyl succinic anhydride (ODSA). They are mainly used in the fields of sizing agents, curing, lubricating oils, solubilizers, corrosion resistance, and rust inhibitors. In particular, as a neutral sizing agent in papermaking, it not only has a fast sizing speed, but also can extend the service life of paper, prevent the paper from yellowing and becoming brittle, improve the wear resistance of paper, and improve the chemical environment of the papermaking process.

[0003] The traditional production process of ASA is mainly to synthesize olefins and maleic anhydride through a stirred reactor at high temperature for a long time. For example, a Chinese patent (authorization announcement number is CN 112898248 B) discloses a method for preparing alkenyl succinic anhydride, which is intermittent operation, long production cycle, high energy consumption, and the product is obtained by distillation and refining, with low yield, and the tar substrate is difficult to handle after refining. In addition, maleic anhydride and internal olefins are prone to self-polymerization under long-term high temperature conditions, resulting in increased and complex side reactions, and there are more coking insolubles on the wall of the reactor that are difficult to handle; the production process is complicated, there are many engineering equipment, and the floor space is large. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a continuous synthesis process of alkenyl succinic anhydride. Compared with the traditional production process, it realizes continuous production, has a simple process flow, and is safer. At the same time, it effectively reduces energy consumption and equipment investment costs, and is easy to realize large-scale industrial application production.

[0005] On one hand, the present invention provides a continuous synthesis process of alkenyl succinic anhydride, which comprises at least the following steps: a solid-supported AlCl3 catalyst is loaded in a fixed bed reactor; a preheated mixture of maleic anhydride and internal olefin enters the fixed bed reactor, contacts with the solid-supported AlCl3 catalyst and undergoes a catalytic reaction to synthesize a crude product, the crude product is cooled, the olefin is separated and recovered by distillation, and the alkenyl succinic anhydride product is obtained after filtering.

[0006] As a preferred technical solution, the preparation device of the immobilized AlCl3 catalyst at least includes a nitrogen bottle, a drying tube, a flow meter, a tubular immobilized reactor, a heating bypass pipe outside the loading zone, a loading zone, a heating bypass pipe outside the gasification zone, a gasification zone, and a tail gas receiving bottle, wherein the nitrogen bottle, the drying tube, the tubular immobilized reactor, and the tail gas receiving bottle are connected in sequence, a flow meter is arranged between the drying tube and the tubular immobilized reactor, the interior of the tubular immobilized reactor is divided into a loading zone and a gasification zone, the gasification zone and the loading zone are respectively supported by a porous sieve plate, a heating bypass pipe outside the loading zone is arranged outside the loading zone, and a heating bypass pipe outside the gasification zone is arranged outside the gasification zone.

[0007] As a preferred technical solution, the preparation method of the immobilized AlCl3 catalyst comprises at least the following steps: filling anhydrous AlCl3 in the gasification zone of the tubular immobilized reactor, filling the calcined carrier in the loading zone of the tubular immobilized reactor, and heating the gasification zone to 200-220°C after nitrogen replaces the internal gas of the tubular immobilized reactor, introducing high-purity nitrogen at a rated flow rate at this temperature, and the generated AlCl3 steam is brought into the loading zone of the immobilized reactor by the high-purity nitrogen, and the temperature is controlled to carry out the loading reaction. After the reaction is completed, stop introducing AlCl3, and obtain the immobilized AlCl3 catalyst by blowing and cooling under nitrogen protection.

[0008] As a preferred technical solution, the temperature of the loading reaction is 190-240°C, preferably 200-220°C.

[0009] As a preferred technical solution, the load reaction time is 2-7h, preferably 3-5h.

[0010] As a preferred technical solution, the inlet flow rate of the high-purity nitrogen is 60-120 mL / min, preferably 70-90 mL / min.

[0011] As a preferred technical solution, the preparation method of the calcined carrier is: the carrier is calcined at a constant temperature of 400-600°C for 2-4h, and the calcined carrier is obtained after cooling to 15-30°C.

[0012] As a preferred technical solution, the carrier is a mesoporous structure with a specific surface area of ​​150-200m 2 / g, and the average particle size is 10-20nm.

[0013] Preferably, the carrier is γ-Al2O3.

[0014] As a preferred technical solution, the added mass ratio of the anhydrous AlCl3 and the calcined carrier is (1-6):10, preferably (3-5):10.

[0015] As a preferred technical solution, the structural formula of the internal olefin is C n H 2n , n=12-20.

[0016] As a preferred technical solution, the molar ratio of maleic anhydride to internal olefin is 1:(1-6), preferably 1:(2-4).

[0017] As a preferred technical solution, the temperature of the mixed material is 160-230°C, preferably 190-220°C.

[0018] As a preferred technical solution, the temperature of the catalytic reaction is 160-230°C, preferably 190-220°C.

[0019] As a preferred technical solution, the mass space velocity of the mixed material entering the fixed bed reactor is 1.0-2.0h -1 , preferably 1.4-1.7h -1 .

[0020] The continuous synthesis process provided by the present invention adopts a solid-supported AlCl3 catalyst and a fixed bed reactor, greatly shortens the reaction time, improves the reaction rate, effectively inhibits the self-polymerization or cross-polymerization reaction of reactants and products, and solves the problems of long reaction time and low yield in the synthesis of alkenyl succinic anhydride in the prior art. In particular, γ-Al2O3 is used as a carrier to immobilize AlCl3, and the addition mass ratio of anhydrous AlCl3 and the calcined carrier is controlled in the preparation process, and the loading reaction conditions are controlled to ensure the selectivity and catalytic reaction efficiency of the catalyst for the subsequent catalytic reaction of maleic anhydride and internal olefins.

[0021] Further comprehensive control of the molar ratio of maleic anhydride to internal olefin, the temperature of the mixture, the temperature of the catalytic reaction and the mass space velocity of the mixture entering the fixed bed reactor can reduce the occurrence of side reactions, reduce the product color number, and improve the reaction selectivity and yield.

[0022] On the other hand, the present invention provides a continuous synthesis device for alkenyl succinic anhydride, which at least comprises an internal olefin raw material tank, an internal olefin metering pump, a maleic anhydride raw material tank, a maleic anhydride metering pump, a preheater, a fixed bed reactor, and a crude product receiving bottle. The internal olefin metering pump is arranged between the internal olefin raw material tank and the preheater, the maleic anhydride metering pump is arranged between the maleic anhydride raw material tank and the preheater, and the preheater is connected to the fixed bed reactor and the crude product receiving bottle in sequence.

[0023] The continuous synthesis device of alkenyl succinic anhydride provided by the invention is simple, easy to operate, high in production efficiency, small in floor space, low in energy consumption, and has extremely high market application and promotion value.

[0024] Beneficial Effects

[0025] 1. The present invention provides a continuous synthesis process of alkenyl succinic anhydride. Compared with the traditional production process, it realizes continuous production, has a simple process flow, and is safer. At the same time, it effectively reduces energy consumption and equipment investment costs, and is easy to realize large-scale industrial application production.

[0026] 2. The continuous synthesis process provided by the present invention adopts a solid-supported AlCl3 catalyst and a fixed bed reactor, which greatly shortens the reaction time, improves the reaction rate, and effectively inhibits the self-polymerization or cross-polymerization reaction of the reactants and products, thereby solving the problems of long reaction time and low yield in the prior art for synthesizing alkenyl succinic anhydride.

[0027] 3. The present invention uses γ-Al2O3 as a carrier to immobilize AlCl3, and controls the added mass ratio of anhydrous AlCl3 and the calcined carrier and the loading reaction conditions during the preparation process to ensure the selectivity and efficiency of the catalyst in the subsequent catalytic reaction of maleic anhydride and internal olefins.

[0028] 4. The present invention comprehensively controls the molar ratio of maleic anhydride and internal olefin, the temperature of the mixture, the temperature of the catalytic reaction and the mass space velocity of the mixture entering the fixed bed reactor, thereby reducing the occurrence of side reactions, lowering the product color number, and improving the reaction selectivity and yield.

[0029] 5. The continuous synthesis device of alkenyl succinic anhydride provided by the present invention is simple, easy to operate, has high production efficiency, small footprint, low energy consumption, and has extremely high market application and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the preparation device of the immobilized AlCl3 catalyst in Example 1 of the present invention, in which: 1. nitrogen bottle; 2. drying tube; 3. flow meter; 4. tubular immobilized reactor; 5. external heating bypass pipe of the loading zone; 6. loading zone; 7. external heating bypass pipe of the gasification zone; 8. gasification zone; 9. tail gas receiving bottle.

[0031] Figure 2 Schematic diagram of the continuous synthesis device of alkenyl succinic anhydride provided in Example 1 of the present invention, in which: 1. internal olefin raw material tank; 2. internal olefin metering pump; 3. maleic anhydride raw material tank; 4. maleic anhydride metering pump; 5. preheater; 6. fixed bed reactor; 7. crude product receiving bottle. DETAILED DESCRIPTION

[0032] Example 1

[0033] Embodiment 1 of the present invention provides a continuous synthesis process of alkenyl succinic anhydride, comprising the following steps: 60g of immobilized AlCl3 catalyst is loaded in a fixed bed reactor; maleic anhydride is loaded in a maleic anhydride raw material tank, internal olefin is loaded in a raw material tank for internal olefin, the maleic anhydride raw material tank is heated to 70°C to make the maleic anhydride in a hot melt state, the maleic anhydride metering pump controls the maleic anhydride flow rate in the hot melt state to be 0.2g / min, the internal olefin metering pump controls the internal olefin flow rate to be 1.40g / min, the maleic anhydride and octadecene molar ratio under this feed flow rate is 1:2.72, and the mixed materials enter a preheater together, the preheated mixed materials enter a fixed bed reactor, contact with the immobilized AlCl3 catalyst and perform a catalytic reaction to synthesize a crude product, the crude product enters a crude product receiving bottle after being cooled by a cooler, the olefin is separated and recovered by distillation under negative pressure, and the alkenyl succinic anhydride product is obtained after filtration.

[0034] See also Figure 1 The preparation device of the immobilized AlCl3 catalyst comprises a nitrogen bottle 1, a drying tube 2, a flow meter 3, a tubular immobilized reactor 4, a loading zone external heating bypass pipe 5, a loading zone 6, a gasification zone external heating bypass pipe 7, a gasification zone 8, and a tail gas receiving bottle 9, wherein the nitrogen bottle 1, the drying tube 2, the tubular immobilized reactor 4, and the tail gas receiving bottle 9 are connected in sequence, a flow meter 3 is arranged between the drying tube 2 and the tubular immobilized reactor 4, the interior of the tubular immobilized reactor 4 is divided into a loading zone 6 and a gasification zone 7, the gasification zone 8 and the loading zone 6 are respectively supported by a porous sieve plate, an external heating bypass pipe 5 of the loading zone 6 is arranged outside the loading zone 6, and an external heating bypass pipe 7 of the gasification zone 8 is arranged outside the gasification zone 8.

[0035] The preparation method of the immobilized AlCl3 catalyst comprises the following steps: 24g of anhydrous AlCl3 is filled in the gasification zone of the tubular immobilized reactor, 60g of the calcined carrier is filled in the loading zone of the tubular immobilized reactor, the gasification zone is heated to 210°C after nitrogen replaces the internal gas of the tubular immobilized reactor, high-purity nitrogen with a rated flow rate is introduced at this temperature, the generated AlCl3 steam is brought into the loading zone of the immobilized reactor by the high-purity nitrogen, and the loading reaction is carried out by controlling the temperature. After the reaction is completed, the introduction of AlCl3 is stopped, and the immobilized AlCl3 catalyst is obtained by purging and cooling under nitrogen protection.

[0036] The temperature of the loading reaction was 210°C.

[0037] The load reaction time is 4 hours.

[0038] The inlet flow rate of the high-purity nitrogen is 80 mL / min.

[0039] The preparation method of the calcined carrier is as follows: the carrier is calcined at a constant temperature of 500° C. for 3 hours, and then cooled to 25° C. to obtain the calcined carrier.

[0040] The carrier is γ-Al2O3, which has a mesoporous structure and a specific surface area of ​​150-200m 2 / g, average particle size is 10-20nm. Manufacturer: Beijing Dekedaojin Technology Co., Ltd., model DK410-2.

[0041] The internal olefin is octadecene.

[0042] The temperature of the mixed material is 210°C.

[0043] The temperature of the catalytic reaction is 210°C.

[0044] The mass space velocity of the mixed material entering the fixed bed reactor is 1.60h -1 .

[0045] See also Figure 2 On the other hand, the present invention provides a continuous synthesis device of alkenyl succinic anhydride, comprising an internal olefin raw material tank 1, an internal olefin metering pump 2, a maleic anhydride raw material tank 3, a maleic anhydride metering pump 4, a preheater 5, a fixed bed reactor 6, and a crude product receiving bottle 7. The internal olefin metering pump 2 is arranged between the internal olefin raw material tank 1 and the preheater 5, the maleic anhydride metering pump 4 is arranged between the maleic anhydride raw material tank 3 and the preheater 5, and the preheater 5 is connected to the fixed bed reactor 6 and the crude product receiving bottle 7 in sequence.

[0046] Example 2

[0047] Example 2 of the present invention provides a continuous synthesis process and apparatus for alkenyl succinic anhydride, and its specific implementation method is the same as that of Example 1, except that the maleic anhydride metering pump controls the maleic anhydride flow rate in the hot melt state to be 0.26 g / min, and the internal olefin metering pump controls the internal olefin flow rate to be 1.34 g / min. At this feed flow rate, the molar ratio of maleic anhydride to octadecene is 1:2.

[0048] Example 3

[0049] Example 3 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride. The specific implementation method is the same as that of Example 1, except that the maleic anhydride metering pump controls the maleic anhydride flow rate in the hot melt state to be 0.4 g / min, and the internal olefin metering pump controls the internal olefin flow rate to be 1.80 g / min. At this feed flow rate, the molar ratio of maleic anhydride to octadecene is 1:1.75, and the mass space velocity of the mixed material entering the fixed bed reactor is 2.20 h -1 .

[0050] Example 4

[0051] Example 4 of the present invention provides a continuous synthesis process and apparatus for alkenyl succinic anhydride, and its specific implementation is the same as that of Example 1, except that the temperature of the mixed material is 190°C and the temperature of the catalytic reaction is 190°C.

[0052] Example 5

[0053] Example 5 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride. The specific implementation method is the same as that of Example 1, except that the maleic anhydride metering pump controls the maleic anhydride flow rate in the hot melt state to be 0.2 g / min, and the internal olefin metering pump controls the internal olefin flow rate to be 1.50 g / min. At this feed flow rate, the molar ratio of maleic anhydride to octadecene is 1:2.91, and the mass space velocity of the mixed material entering the fixed bed reactor is 1.70 h -1 , the temperature of the mixed material is 150°C, and the temperature of the catalytic reaction is 150°C.

[0054] Example 6

[0055] Example 6 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride, and its specific implementation is the same as that of Example 1, except that 18 g of anhydrous AlCl3 is filled in the gasification zone of the tubular solid-supported reactor, and 60 g of a calcined carrier is filled in the loading zone of the tubular solid-supported reactor. The loading reaction temperature is 220° C., and the loading reaction time is 3 h.

[0056] Example 7

[0057] Example 7 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride, and its specific implementation is the same as that of Example 1, except that 12 g of anhydrous AlCl3 is filled in the gasification zone of the tubular solid-supported reactor, and 60 g of a calcined carrier is filled in the loading zone of the tubular solid-supported reactor. The loading reaction temperature is 220° C., and the loading reaction time is 8 h.

[0058] Example 8

[0059] Example 8 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride, and its specific implementation is the same as that of Example 1, except that 48 g of anhydrous AlCl3 is filled in the gasification zone of the tubular solid-supported reactor, and 60 g of the calcined carrier is filled in the loading zone of the tubular solid-supported reactor. The loading reaction temperature is 200° C., and the loading reaction time is 3 h.

[0060] Example 9

[0061] Example 9 of the present invention provides a continuous synthesis process and apparatus for alkenyl succinic anhydride, and its specific implementation is the same as that of Example 1, except that the temperature of the loading reaction is 250° C., and the time of the loading reaction is 3 hours.

[0062] Example 10

[0063] Example 10 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride, and its specific implementation is the same as that of Example 1, except that 30 g of anhydrous AlCl3 is filled in the gasification zone of the tubular solid-supported reactor, and 60 g of a calcined carrier is filled in the loading zone of the tubular solid-supported reactor. The loading reaction temperature is 200° C., and the loading reaction time is 3 h.

[0064] Embodiment 11

[0065] Example 11 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride, and its specific implementation method is the same as that of Example 1, except that the internal olefin is replaced by hexadecene, the maleic anhydride metering pump controls the maleic anhydride flow rate in the hot melt state to be 0.2 g / min, and the internal olefin metering pump controls the internal olefin flow rate to be 1.30 g / min. At this feed flow rate, the molar ratio of maleic anhydride to hexadecene is 1:2.84, and the mass space velocity of the mixed material entering the fixed bed reactor is 1.50 h -1 , the temperature of the mixed material is 200°C, and the temperature of the catalytic reaction is 200°C.

[0066] Example 12

[0067] Example 12 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride, and its specific implementation method is the same as that of Example 1, except that the internal olefin is replaced by hexadecene, the maleic anhydride metering pump controls the maleic anhydride flow rate in the hot melt state to be 0.2 g / min, and the internal olefin metering pump controls the internal olefin flow rate to be 1.50 g / min. At this feed flow rate, the molar ratio of maleic anhydride to hexadecene is 1:3.28, and the mass space velocity of the mixed material entering the fixed bed reactor is 1.70 h -1 , the temperature of the mixed material is 200°C, and the temperature of the catalytic reaction is 200°C.

[0068] Example 13

[0069] Example 13 of the present invention provides a continuous synthesis process and device for alkenyl succinic anhydride, and its specific implementation method is the same as that of Example 1, except that the internal olefin is replaced by dodecene, the maleic anhydride metering pump controls the maleic anhydride flow rate in the hot melt state to be 0.3 g / min, and the internal olefin metering pump controls the internal olefin flow rate to be 1.40 g / min. At this feed flow rate, the molar ratio of maleic anhydride to dodecene is 1:2.70, and the mass space velocity of the mixed material entering the fixed bed reactor is 1.70 h -1 , the temperature of the mixed material is 200°C, and the temperature of the catalytic reaction is 200°C.

[0070] Performance Testing

[0071] The yield of the alkenyl succinic anhydride product provided in Examples 1-13 was calculated based on maleic anhydride, and the purity (GCMS area normalization method) and color number of the alkenyl succinic anhydride product provided in Examples 1-13 were tested. The test results are shown in Table 1.

[0072] Table 1

[0073] Example Yield / % purity / % Color number (Fe-Co) Example 1 97.3 99.2 9 Example 2 94.9 98.8 9 Example 3 83.8 97.7 8 Example 4 93.4 99.5 7 Example 5 61.6 97.1 6 Example 6 95.6 98.5 8 Example 7 90.5 97.7 7 Example 8 77.6 95.1 10 Example 9 71.1 94.2 11 Example 10 95.0 98.7 8 Embodiment 11 97.5 99.0 8 Example 12 96.8 99.2 8 Example 13 96.4 98.5 8

Claims

1. A continuous synthesis process for alkenyl succinic anhydride, characterized in that: At least the following steps are included: The immobilized AlCl3 catalyst is loaded in a fixed bed reactor; the preheated mixture of maleic anhydride and internal olefin enters the fixed bed reactor, contacts with the immobilized AlCl3 catalyst and undergoes a catalytic reaction to synthesize a crude product; the crude product is cooled, separated by distillation to recover the olefin, and filtered to obtain an alkenyl succinic anhydride product.

2. A continuous synthesis process for alkenyl succinic anhydride according to claim 1, characterized in that: The preparation device of the immobilized AlCl3 catalyst at least comprises a nitrogen bottle, a drying tube, a flow meter, a tubular immobilized reactor, a heating bypass pipe outside the loading zone, a loading zone, a heating bypass pipe outside the gasification zone, a gasification zone, and a tail gas receiving bottle, wherein the nitrogen bottle, the drying tube, the tubular immobilized reactor, and the tail gas receiving bottle are connected in sequence, a flow meter is arranged between the drying tube and the tubular immobilized reactor, the interior of the tubular immobilized reactor is divided into a loading zone and a gasification zone, the gasification zone and the loading zone are respectively supported by porous sieve plates, a heating bypass pipe outside the loading zone is arranged outside the loading zone, and a heating bypass pipe outside the gasification zone is arranged outside the gasification zone.

3. A continuous synthesis process for alkenyl succinic anhydride according to claim 2, characterized in that: The preparation method of the immobilized AlCl3 catalyst comprises at least the following steps: filling anhydrous AlCl3 in the gasification zone of the tubular immobilized reactor, filling the calcined carrier in the loading zone of the tubular immobilized reactor, heating the gasification zone to 200-220°C after nitrogen replaces the gas inside the tubular immobilized reactor, introducing high-purity nitrogen at a rated flow rate at this temperature, and bringing the generated AlCl3 steam into the loading zone of the immobilized reactor by the high-purity nitrogen, and controlling the temperature to carry out the loading reaction; after the reaction is completed, stopping the introduction of AlCl3, and cooling while purging under nitrogen protection to obtain the immobilized AlCl3 catalyst.

4. A continuous synthesis process for alkenyl succinic anhydride according to claim 3, characterized in that: The temperature of the loading reaction is 190-240° C., and the time of the loading reaction is 2-7 hours.

5. A continuous synthesis process for alkenyl succinic anhydride according to claim 4, characterized in that: The high-purity nitrogen gas has an inlet flow rate of 60-120 mL / min.

6. A continuous synthesis process for alkenyl succinic anhydride according to claim 5, characterized in that: The added mass ratio of the anhydrous AlCl3 and the calcined carrier is (1-6):

10.

7. A continuous synthesis process for alkenyl succinic anhydride according to claim 6, characterized in that: The molar ratio of maleic anhydride to internal olefin is 1:(1-6).

8. A continuous synthesis process for alkenyl succinic anhydride according to claim 7, characterized in that: The temperature of the mixed material is 160-230°C, and the temperature of the catalytic reaction is 160-230°C.

9. A continuous synthesis process for alkenyl succinic anhydride according to claim 8, characterized in that: The mass space velocity of the mixed material entering the fixed bed reactor is 1.0-2.0h -1 .

10. A continuous synthesis device for alkenyl succinic anhydride, used for carrying out the continuous synthesis process for alkenyl succinic anhydride according to any one of claims 1 to 9, characterized in that: The method comprises at least an internal olefin raw material tank, an internal olefin metering pump, a maleic anhydride raw material tank, a maleic anhydride metering pump, a preheater, a fixed bed reactor, and a crude product receiving bottle. The internal olefin metering pump is arranged between the internal olefin raw material tank and the preheater, the maleic anhydride metering pump is arranged between the maleic anhydride raw material tank and the preheater, and the preheater is connected with the fixed bed reactor and the crude product receiving bottle in sequence.

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