A wide load adaptive N-methylaniline synthesis system and process

Abstract

The application discloses a wide-load self-adaptive N-methylaniline synthesis system and process, and belongs to the field of chemical technology. The synthesis system comprises n adiabatic reaction units and a self-heating reaction unit, wherein n is an integer greater than or equal to 2; each adiabatic reaction unit comprises an adiabatic reactor, a temperature control raw material gas conveying line and an adiabatic temperature regulating heat exchanger; the self-heating reaction unit comprises a self-heating reactor, a self-heating reactor inlet pipeline and a self-heating temperature regulating heat exchanger. The application further discloses a wide-load self-adaptive N-methylaniline synthesis process implemented by using the system. The synthesis system is designed based on the synthesis process characteristics of N-methylaniline, has a wide adjustment range, high conversion rate, simple control, can realize quick online replacement of a catalyst and stable continuous operation.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to a wide-load adaptive N-methylaniline synthesis system and process. Background Technology

[0002] N-Methylaniline, as an important chemical intermediate, is widely used in pharmaceuticals, pesticides, and dyes due to its excellent anti-explosion properties. Currently, the industrial synthesis of N-methylaniline mainly involves two processes: liquid-phase synthesis and gas-phase synthesis. Liquid-phase synthesis, which uses strong acid catalysts, suffers from severe equipment corrosion, significant environmental pollution, and numerous byproducts that are difficult to separate; therefore, it has been gradually replaced by gas-phase synthesis.

[0003] Gas-phase synthesis employs environmentally friendly solid catalysts, using methanol as the alkylating agent, to catalyze the synthesis of N-methylaniline from aniline in a fixed-bed reactor under gas-phase conditions. Currently, industrially, axial reactors with fixed tubular tubes are commonly used, with heat exchange via heat transfer oil or steam to control the reaction temperature. Copper-based catalysts are frequently used, as these solid catalysts exhibit high catalytic activity and selectivity, with single-pass conversion >90% and selectivity >94%. Nevertheless, existing gas-phase synthesis processes still suffer from the following drawbacks: (1) The catalyst loading and replacement of fixed tube axial reactors are labor-intensive and have a long cycle, which affects the operating efficiency of the unit; (2) Aniline raw materials and products are prone to coking. Although the existing process sets up a filter in front of the reactor and configures a complex coking removal structure inside, the overall structure is complex and the oil and coking removal effect is limited. (3) As the operating time increases, the system pressure drop gradually increases. After coking, the catalyst is difficult to remove from the tube bundle. The service life of the catalyst is generally no more than one year, which is difficult to meet the mainstream requirement of the current chemical industry for a single unit to operate continuously for more than 20,000 hours. (4) The reaction process requires alternating heating and heat removal in multiple temperature ranges, which causes the catalyst to undergo frequent hot and cold cycles (nearly 1000 times) during its life cycle, making temperature control difficult and affecting reaction stability; (5) The market price of N-methylaniline products fluctuates greatly; taking 2024 as an example, the price range is RMB 13,000 to 26,500 per ton. Enterprises need to be able to flexibly adjust their production capacity within a wide load range to match economic needs, but the existing process is not adaptable to the load. (6) The operating pressure of the reaction system is low. Due to the limited transportation radius of the reactor, the production capacity of a single unit is usually difficult to exceed 30,000 tons, which restricts the development of large-scale units.

[0004] In existing technologies, research on the synthesis process of N-methylaniline mainly focuses on aspects such as catalyst synthesis, catalyst reduction, distillation processes, and production safety at Rongsheng Petrochemical. For example, patent CN107115881A discloses a method for preparing and applying a catalyst for the synthesis of N-methylaniline, patent CN116159602A discloses a reduction process using a copper-based catalyst for the synthesis of N-methylaniline, patent CN210480914U discloses an azeotropic distillation system for N-methylaniline wastewater, and patent CN212942821U discloses an emergency venting safety device for the N-methylaniline reaction. However, there is relatively little coverage of key engineering issues such as reactor structure, catalyst lifespan, operational flexibility, and scale-up. Furthermore, while there is considerable research on N,N-dimethylaniline in existing literature, systematic optimization research specifically targeting the N-methylaniline synthesis process remains lacking.

[0005] Therefore, a wide-load adaptive synthesis method suitable for the synthesis of N-methylaniline is needed. This method features simplified reactor structure, high operational flexibility, long catalyst lifetime, excellent anti-coking performance, and easy large-scale production expansion. It aims to solve the problems of difficult catalyst replacement, rapid increase in system pressure drop, complex thermal management, insufficient load adjustment capability, and limited single-unit capacity in the existing technology. This has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] One of the objectives of this invention is to provide a wide-load adaptive N-methylaniline synthesis system; designed according to the characteristics of the N-methylaniline synthesis process, it features a wide adjustment range, high conversion rate, simple control, rapid online catalyst replacement, and stable continuous operation.

[0007] The second objective of this invention is to provide a wide-load adaptive method for synthesizing N-methylaniline, which is implemented using the above-described system.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention discloses a wide-load adaptive N-methylaniline synthesis system, which includes: n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each adiabatic reaction unit includes an adiabatic reactor, a temperature-controlled feed gas delivery line, and an adiabatic temperature-regulating heat exchanger. The feed inlet of the adiabatic reactor is connected to the feed gas delivery line via a pipeline. The inlet of the temperature-controlled feed gas delivery line is connected to the feed gas delivery line, and its outlet is connected to the reaction bed of the adiabatic reactor. The adiabatic temperature-regulating heat exchanger is located on the temperature-controlled feed gas delivery line. The outlets of the adiabatic reactors from the first to the (n-1)th stage are respectively connected to the feed inlet of the next stage adiabatic reactor via pipelines. The self-heating reaction unit includes a self-heating reactor, a self-heating reactor inlet pipeline, and a self-heating temperature regulating heat exchanger. The self-heating temperature regulating heat exchanger is installed on the self-heating reactor inlet pipeline. The self-heating reactor inlet pipeline is connected to each adiabatic reactor via pipelines. A crude product gas delivery line is connected to the outlet of the natural reactor.

[0009] In some embodiments of the present invention, at least one temperature-controlled raw material gas conveying branch line is provided in parallel on the temperature-controlled raw material gas conveying line for conveying part or all of the raw material mixture gas around the adiabatic temperature-regulating heat exchanger.

[0010] In some embodiments of the present invention, the 2nd to nth adiabatic reaction units each include a feed ratio controller A; The outlets of the first to n-1th stage adiabatic reactors are connected to the feed inlet of the next stage adiabatic reactor via a syngas delivery line. The syngas conveying line is connected to the feed ratio controller A via a pipeline, which is used to add vaporized aniline to the syngas after the reaction; Preferably, the syngas conveying line is connected to the next-stage temperature-controlled feed gas conveying line.

[0011] In some embodiments of the present invention, at least one temperature-controlled self-heating reaction raw material gas delivery branch line is connected in parallel on the inlet pipeline of the self-heating reactor, for delivering part or all of the reaction synthesis gas around the self-heating temperature-regulating heat exchanger. Preferably, the self-heating reactor is also equipped with a circulation line; Preferably, the self-heating reaction unit further includes a feed ratio controller B; the outlet of each adiabatic reactor is connected to the inlet pipeline of the self-heating reactor via a pipeline, and the feed ratio controller B is connected to the inlet pipeline of the self-heating reactor via a pipeline.

[0012] In some embodiments of the present invention, the system further includes a cooler, a gas-liquid separator, and a distillation column sequentially connected from the self-heating reactor; Preferably, the self-heating reactor and the cooler are connected via a crude product gas conveying line; Preferably, the liquid phase outlet of the gas-liquid separator is connected to the feed inlet of the distillation column for distillation of the crude N-methylaniline product separated by gas-liquid separation; Preferably, the gas phase outlet of the gas-liquid separator is connected to an external hydrogen purification system.

[0013] In some embodiments of the present invention, valves are installed on each pipeline of the system. The process flow, process parameters and system switching are controlled by opening and closing the valves and adjusting their opening degree.

[0014] A second aspect of this invention discloses a wide-load adaptive N-methylaniline synthesis process, which is implemented using the above-described system, wherein n=2, and includes the following steps: The raw material mixture formed by the vaporization of methanol and aniline is divided into two streams. The main part enters the first-stage adiabatic reactor for reaction, while the remaining part is temperature-regulated by the first-stage adiabatic temperature-regulating heat exchanger and then injected into the bed space of the first-stage adiabatic reactor through the first-stage temperature-controlled raw material gas delivery line to participate in subsequent reactions. The synthesis gas output from the first-stage adiabatic reactor is mixed with vaporized aniline added through the second-stage feed ratio controller A to adjust the feed ratio. The mixed gas is divided into two streams. The main part enters the second-stage adiabatic reactor to continue the reaction, while the remaining part is temperature-regulated by the second-stage adiabatic temperature-regulating heat exchanger and then injected into the bed between the beds of the second-stage adiabatic reactor through the second-stage temperature-controlled feed gas delivery line to participate in subsequent reactions. The synthesis gas output from the second-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The mixed gas is then regulated by a self-heating temperature-regulating heat exchanger and enters the self-heating reactor for further alkylation reaction. Preferably, the synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

[0015] A third aspect of this invention discloses a wide-load adaptive N-methylaniline synthesis process, which is implemented using the above-described system, wherein n=2, and includes the following steps: The raw material mixture formed by the vaporization of methanol and aniline is divided into two streams. The main part enters the first-stage adiabatic reactor for reaction, while the remaining part is temperature-regulated by the first-stage adiabatic temperature-regulating heat exchanger and then injected into the bed space of the first-stage adiabatic reactor through the first-stage temperature-controlled raw material gas delivery line to participate in subsequent reactions. The synthesis gas output from the first-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The mixed gas is then conditioned by a self-heating temperature-regulating heat exchanger and enters the self-heating reactor for further alkylation reaction. The second-stage adiabatic reaction unit was disconnected from the synthesis system, and the catalyst was replaced online. Preferably, the synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

[0016] The fourth aspect of this invention discloses a wide-load adaptive N-methylaniline synthesis process, which is implemented using the above-described system, wherein n=2, and includes the following steps: The raw material mixture formed by mixing vaporized methanol and aniline is fed into the first-stage adiabatic reactor and the second-stage adiabatic reactor for reaction. Simultaneously, a portion of the raw material mixture is fed into the bed space of the first-stage adiabatic reactor after its temperature is regulated by the first-stage adiabatic temperature-regulating heat exchanger and the first-stage temperature-controlled raw material gas delivery branch line. A portion of the raw material mixture is also fed into the bed space of the second-stage adiabatic reactor after its temperature is regulated by the second-stage adiabatic temperature-regulating heat exchanger and the second-stage temperature-controlled raw material gas delivery branch line. The synthesis gas output from the second-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The resulting mixed gas enters the self-heating reactor sequentially through the self-heating temperature control heat exchanger and the inlet pipeline of the self-heating reactor to continue the alkylation reaction. Preferably, the synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

[0017] In some embodiments of the present invention, the self-heating reactor is filled with a portion of methanol cracking catalyst to produce hydrogen as a byproduct during the reaction.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention is scientifically designed and ingeniously conceived. The synthesis system of this invention is designed based on the characteristics of the synthesis process of N-methylaniline, and has the advantages of wide adjustment range, high conversion rate, simple control, rapid online catalyst replacement, and stable continuous operation.

[0019] This invention employs n adiabatic reaction units, enabling rapid loading and replacement of the catalyst, significantly reducing the traditional 7-12 day operation time to 1-2 days.

[0020] The synthesis system of this invention offers flexible operation and high conversion rates. The adiabatic reactor supports series or parallel operation and can be individually shut down for online catalyst replacement without affecting normal system operation. Combined with the design of the self-heating reactor, it ensures that the single-pass conversion rate remains above 99% under various operating conditions.

[0021] The synthesis system using this invention significantly increases production capacity. By arranging adiabatic reactors in parallel, the production capacity of a single system can be increased to over 55,000 tons, which is more than 80% higher than the traditional single-system capacity of 30,000 tons.

[0022] Furthermore, the synthesis system of this invention has a simplified structure and enables online maintenance. This invention eliminates the complex oil removal structures such as filters before and after the reactor and isothermal axial reactors found in traditional processes. It utilizes the catalyst in the upper part of the adiabatic reactor to simultaneously intercept aniline coking during deactivation. Based on changes in bed pressure drop, some of the coking catalyst can be quickly replaced online at any time, ensuring continuous and stable operation of the unit.

[0023] The synthesis system of this invention features temperature control and operational safety. The adiabatic reactor adopts a segmented design, and temperature control is achieved by supplementing fresh gas between the two catalyst stages, maintaining a stable bed temperature. This effectively avoids vessel fatigue and safety hazards caused by frequent hot-cold switching of the heat medium in traditional processes, and solves the problem of nearly a thousand hot-cold alternations throughout the catalyst's entire life cycle. Attached Figure Description

[0024] Appendix Figure 1 This is a schematic diagram of the system of the present invention.

[0025] Appendix Figure 2 The above are process flow diagrams for Embodiments 7 and 10 of the present invention.

[0026] Appendix Figure 3 This is a process flow diagram of Embodiment 8 of the present invention.

[0027] Appendix Figure 4 This is a process flow diagram of Embodiment 9 of the present invention.

[0028] The names corresponding to the reference numerals in the attached figures are: 1-Insulated reactor, 2-Insulated temperature-regulating heat exchanger, 3-Self-heating reactor, 4-Self-heating temperature-regulating heat exchanger, 5-Feed ratio controller A, 6-Feed ratio controller B, 7-Cooler, 8-Gas-liquid separator, 9-Distillation column. 101-Temperature-controlled raw material gas conveying line, 102-Raw material mixed gas conveying line, 103-Self-heating reactor inlet pipeline, 104-Temperature-controlled raw material gas conveying branch line, 105-Synthesis gas conveying line, 106-Temperature-controlled self-heating reaction raw material gas conveying branch line, 107-Circulation line, 108-Crude product gas conveying line. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1 As attached Figure 1 As shown, this embodiment discloses a wide-load adaptive N-methylaniline synthesis system, which includes n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each of the aforementioned adiabatic reaction units includes an adiabatic reactor 1, a temperature-controlled feed gas delivery line 101, and an adiabatic temperature-regulating heat exchanger 2; the feed inlet of the adiabatic reactor 1 is connected to the feed gas delivery line 102 via a pipeline, the inlet of the temperature-controlled feed gas delivery line 101 is connected to the feed gas delivery line 102, and its outlet is connected to the reaction bed of the adiabatic reactor 1; the adiabatic temperature-regulating heat exchanger 2 is disposed on the temperature-controlled feed gas delivery line 101; the outlets of the adiabatic reactors 1 from the first to the (n-1)th stage are respectively connected to the feed inlet of the next stage adiabatic reactor 1 via pipelines. The self-heating reaction unit includes a self-heating reactor 3, a self-heating reactor inlet pipeline 103, and a self-heating temperature regulating heat exchanger 4. The self-heating temperature regulating heat exchanger 4 is installed on the self-heating reactor inlet pipeline 103. The self-heating reactor inlet pipeline 103 is connected to each adiabatic reactor 1 via pipelines. A crude product gas delivery line 108 is connected to the outlet of the natural reactor 3.

[0031] This invention constructs a highly efficient, flexible, and wide-load adaptive N-methylaniline synthesis system by employing a combination design of n adiabatic reaction units and one self-heating reaction unit. The system is highly flexible in operation; the adiabatic reactors can be operated in series and parallel, and the catalyst can be replaced individually online, ensuring that the single-pass conversion rate is consistently maintained above 99%. Maintenance is convenient; the catalyst replacement time is significantly reduced from the traditional 7-12 days to 1-2 days, and the coking catalyst can be quickly replaced online, ensuring long-term stable operation. Production capacity is significantly increased; through parallel arrangement, the production capacity of a single system is increased by more than 80%. Operation is safe; through segmented temperature control technology, it effectively solves the equipment fatigue and safety hazards caused by frequent switching of heat transfer media in traditional processes. The overall system structure is simplified, with a wide adjustment range, easy control, and excellent comprehensive performance.

[0032] Example 2 As attached Figure 1 As shown, this embodiment discloses a wide-load adaptive N-methylaniline synthesis system, which includes n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each of the aforementioned adiabatic reaction units includes an adiabatic reactor 1, a temperature-controlled feed gas delivery line 101, and an adiabatic temperature-regulating heat exchanger 2; the feed inlet of the adiabatic reactor 1 is connected to the feed gas delivery line 102 via a pipeline, the inlet of the temperature-controlled feed gas delivery line 101 is connected to the feed gas delivery line 102, and its outlet is connected to the reaction bed of the adiabatic reactor 1; the adiabatic temperature-regulating heat exchanger 2 is disposed on the temperature-controlled feed gas delivery line 101; the outlets of the adiabatic reactors 1 from the first to the (n-1)th stage are respectively connected to the feed inlet of the next stage adiabatic reactor 1 via pipelines. The self-heating reaction unit includes a self-heating reactor 3, a self-heating reactor inlet pipeline 103, and a self-heating temperature regulating heat exchanger 4. The self-heating temperature regulating heat exchanger 4 is installed on the self-heating reactor inlet pipeline 103. The self-heating reactor inlet pipeline 103 is connected to each adiabatic reactor 1 via pipelines. A crude product gas delivery line 108 is connected to the outlet of the natural reactor 3.

[0033] At least one temperature-controlled raw material gas conveying branch line 104 is connected in parallel on the temperature-controlled raw material gas conveying line 101 to convey part or all of the raw material mixed gas around the insulated temperature-regulating heat exchanger 2.

[0034] This embodiment 2 provides a more preferred technical solution based on embodiment 1. Specifically, at least one temperature-controlled raw material gas delivery branch line 104 is connected in parallel on the temperature-controlled raw material gas delivery line 101, used to deliver part or all of the raw material mixture gas around the adiabatic temperature-regulating heat exchanger 2. This embodiment 2 achieves flexible and precise control of the reactor inlet temperature through parallel branches, effectively improving the system's response speed and adaptability to load changes.

[0035] Example 3 As attached Figure 1 As shown, this embodiment discloses a wide-load adaptive N-methylaniline synthesis system, which includes n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each of the aforementioned adiabatic reaction units includes an adiabatic reactor 1, a temperature-controlled feed gas delivery line 101, and an adiabatic temperature-regulating heat exchanger 2; the feed inlet of the adiabatic reactor 1 is connected to the feed gas delivery line 102 via a pipeline, the inlet of the temperature-controlled feed gas delivery line 101 is connected to the feed gas delivery line 102, and its outlet is connected to the reaction bed of the adiabatic reactor 1; the adiabatic temperature-regulating heat exchanger 2 is disposed on the temperature-controlled feed gas delivery line 101; the outlets of the adiabatic reactors 1 from the first to the (n-1)th stage are respectively connected to the feed inlet of the next stage adiabatic reactor 1 via pipelines. The self-heating reaction unit includes a self-heating reactor 3, a self-heating reactor inlet pipeline 103, and a self-heating temperature regulating heat exchanger 4. The self-heating temperature regulating heat exchanger 4 is installed on the self-heating reactor inlet pipeline 103. The self-heating reactor inlet pipeline 103 is connected to each adiabatic reactor 1 via pipelines. A crude product gas delivery line 108 is connected to the outlet of the natural reactor 3.

[0036] At least one temperature-controlled raw material gas conveying branch line 104 is connected in parallel on the temperature-controlled raw material gas conveying line 101 to convey part or all of the raw material mixed gas around the insulated temperature-regulating heat exchanger 2.

[0037] Each of the 2nd to nth adiabatic reaction units includes a feed ratio controller A5; The outlets of the first to n-1th stage adiabatic reactors 1 are connected to the feed inlet of the next stage adiabatic reactor 1 via syngas conveying line 105. The syngas conveying line 105 is connected to the feed ratio controller A5 via a pipeline, which is used to add vaporized aniline to the syngas after the reaction. The syngas delivery line 105 is connected to the next-level temperature-controlled raw material gas delivery line 101.

[0038] This embodiment 3 provides a more preferred technical solution based on embodiment 2. Specifically: each of the 2nd to nth adiabatic reaction units includes a feed ratio controller A5; the outlet of the adiabatic reactor 1 from the 1st to the (n-1th)th stage is connected to the raw material inlet of the next stage adiabatic reactor 1 via a syngas conveying line 105; the syngas conveying line 105 is connected to the feed ratio controller A5 via a pipeline for adding vaporized aniline to the syngas after the reaction; the syngas conveying line 105 is connected to the next stage temperature-controlled raw material gas conveying line 101. This embodiment 3, by supplementing with vaporized aniline, precisely controls the feed ratio of subsequent reactors, thereby optimizing the reaction process and effectively improving the overall conversion rate and reaction efficiency of the raw materials.

[0039] Example 4 As attached Figure 1 As shown, this embodiment discloses a wide-load adaptive N-methylaniline synthesis system, which includes n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each of the aforementioned adiabatic reaction units includes an adiabatic reactor 1, a temperature-controlled feed gas delivery line 101, and an adiabatic temperature-regulating heat exchanger 2; the feed inlet of the adiabatic reactor 1 is connected to the feed gas delivery line 102 via a pipeline, the inlet of the temperature-controlled feed gas delivery line 101 is connected to the feed gas delivery line 102, and its outlet is connected to the reaction bed of the adiabatic reactor 1; the adiabatic temperature-regulating heat exchanger 2 is disposed on the temperature-controlled feed gas delivery line 101; the outlets of the adiabatic reactors 1 from the first to the (n-1)th stage are respectively connected to the feed inlet of the next stage adiabatic reactor 1 via pipelines. The self-heating reaction unit includes a self-heating reactor 3, a self-heating reactor inlet pipeline 103, and a self-heating temperature regulating heat exchanger 4. The self-heating temperature regulating heat exchanger 4 is installed on the self-heating reactor inlet pipeline 103. The self-heating reactor inlet pipeline 103 is connected to each adiabatic reactor 1 via pipelines. A crude product gas delivery line 108 is connected to the outlet of the natural reactor 3.

[0040] At least one temperature-controlled raw material gas conveying branch line 104 is connected in parallel on the temperature-controlled raw material gas conveying line 101 to convey part or all of the raw material mixed gas around the insulated temperature-regulating heat exchanger 2.

[0041] Each of the 2nd to nth adiabatic reaction units includes a feed ratio controller A5; The outlets of the first to n-1th stage adiabatic reactors 1 are connected to the feed inlet of the next stage adiabatic reactor 1 via syngas conveying line 105. The syngas conveying line 105 is connected to the feed ratio controller A5 via a pipeline, which is used to add vaporized aniline to the syngas after the reaction. The syngas delivery line 105 is connected to the next-level temperature-controlled raw material gas delivery line 101.

[0042] At least one temperature-controlled self-heating reaction raw material gas conveying branch line 106 is connected in parallel on the inlet pipeline 103 of the self-heating reactor to convey part or all of the reaction synthesis gas around the self-heating temperature-regulating heat exchanger 4; the self-heating reactor 3 is also provided with a circulation line 107. The self-heating reaction unit also includes a feed ratio controller B6; the outlet of each adiabatic reactor 1 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline, and the feed ratio controller B6 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline.

[0043] This embodiment 4 provides a more preferred technical solution based on embodiment 3. Specifically: at least one temperature-controlled self-heating reaction feed gas delivery branch line 106 is connected in parallel to the inlet pipeline 103 of the self-heating reactor, used to transport part or all of the reaction synthesis gas around the self-heating temperature-regulating heat exchanger 4; the self-heating reactor 3 is also provided with a circulation line 107; the self-heating reaction unit also includes a feed ratio controller B6; the outlet of each adiabatic reactor 1 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline, and the feed ratio controller B6 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline. This embodiment 4, through parallel branches and circulation lines, precisely controls the inlet temperature and reactant ratio of the self-heating reactor, thereby achieving optimal reaction conditions within a wide load range, further improving the conversion rate and ensuring stable system operation.

[0044] Example 5 As attached Figure 1 As shown, this embodiment discloses a wide-load adaptive N-methylaniline synthesis system, which includes n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each of the aforementioned adiabatic reaction units includes an adiabatic reactor 1, a temperature-controlled feed gas delivery line 101, and an adiabatic temperature-regulating heat exchanger 2; the feed inlet of the adiabatic reactor 1 is connected to the feed gas delivery line 102 via a pipeline, the inlet of the temperature-controlled feed gas delivery line 101 is connected to the feed gas delivery line 102, and its outlet is connected to the reaction bed of the adiabatic reactor 1; the adiabatic temperature-regulating heat exchanger 2 is disposed on the temperature-controlled feed gas delivery line 101; the outlets of the adiabatic reactors 1 from the first to the (n-1)th stage are respectively connected to the feed inlet of the next stage adiabatic reactor 1 via pipelines. The self-heating reaction unit includes a self-heating reactor 3, a self-heating reactor inlet pipeline 103, and a self-heating temperature regulating heat exchanger 4. The self-heating temperature regulating heat exchanger 4 is installed on the self-heating reactor inlet pipeline 103. The self-heating reactor inlet pipeline 103 is connected to each adiabatic reactor 1 via pipelines. A crude product gas delivery line 108 is connected to the outlet of the natural reactor 3.

[0045] At least one temperature-controlled raw material gas conveying branch line 104 is connected in parallel on the temperature-controlled raw material gas conveying line 101 to convey part or all of the raw material mixed gas around the insulated temperature-regulating heat exchanger 2.

[0046] Each of the 2nd to nth adiabatic reaction units includes a feed ratio controller A5; The outlets of the first to n-1th stage adiabatic reactors 1 are connected to the feed inlet of the next stage adiabatic reactor 1 via syngas conveying line 105. The syngas conveying line 105 is connected to the feed ratio controller A5 via a pipeline, which is used to add vaporized aniline to the syngas after the reaction. The syngas delivery line 105 is connected to the next-level temperature-controlled raw material gas delivery line 101.

[0047] At least one temperature-controlled self-heating reaction raw material gas conveying branch line 106 is connected in parallel on the inlet pipeline 103 of the self-heating reactor to convey part or all of the reaction synthesis gas around the self-heating temperature-regulating heat exchanger 4; the self-heating reactor 3 is also provided with a circulation line 107. The self-heating reaction unit also includes a feed ratio controller B6; the outlet of each adiabatic reactor 1 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline, and the feed ratio controller B6 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline.

[0048] The wide-load adaptive N-methylaniline synthesis system also includes a cooler 7, a gas-liquid separator 8, and a distillation column 9 connected sequentially from the self-heating reactor 3; The self-heating reactor 3 and the cooler 7 are connected by a crude product gas conveying line 108. The liquid phase outlet of the gas-liquid separator 8 is connected to the raw material inlet of the distillation column 9 for distillation of the crude N-methylaniline product separated by gas-liquid separation; The gas phase outlet of gas-liquid separator 8 is connected to an external hydrogen purification system.

[0049] This embodiment 5 provides a more preferred technical solution based on embodiment 4. Specifically, the wide-load adaptive N-methylaniline synthesis system further includes a cooler 7, a gas-liquid separator 8, and a distillation column 9 sequentially connected from the self-heating reactor 3; the self-heating reactor 3 and the cooler 7 are connected via a crude product gas conveying line 108; the liquid phase outlet of the gas-liquid separator 8 is connected to the raw material inlet of the distillation column 9 for distillation of the crude N-methylaniline product separated by gas-liquid separation; the gas phase outlet of the gas-liquid separator 8 is connected to an external hydrogen purification system. This embodiment 5, by integrating the post-reaction processing unit, achieves integrated distillation of reaction and separation, directly obtaining high-purity products and realizing the recovery and utilization of unreacted raw materials, thereby improving the overall process efficiency and economic benefits.

[0050] Example 6 As attached Figure 1 As shown, this embodiment discloses a wide-load adaptive N-methylaniline synthesis system, which includes n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each of the aforementioned adiabatic reaction units includes an adiabatic reactor 1, a temperature-controlled feed gas delivery line 101, and an adiabatic temperature-regulating heat exchanger 2; the feed inlet of the adiabatic reactor 1 is connected to the feed gas delivery line 102 via a pipeline, the inlet of the temperature-controlled feed gas delivery line 101 is connected to the feed gas delivery line 102, and its outlet is connected to the reaction bed of the adiabatic reactor 1; the adiabatic temperature-regulating heat exchanger 2 is disposed on the temperature-controlled feed gas delivery line 101; the outlets of the adiabatic reactors 1 from the first to the (n-1)th stage are respectively connected to the feed inlet of the next stage adiabatic reactor 1 via pipelines. The self-heating reaction unit includes a self-heating reactor 3, a self-heating reactor inlet pipeline 103, and a self-heating temperature regulating heat exchanger 4. The self-heating temperature regulating heat exchanger 4 is installed on the self-heating reactor inlet pipeline 103. The self-heating reactor inlet pipeline 103 is connected to each adiabatic reactor 1 via pipelines. A crude product gas delivery line 108 is connected to the outlet of the natural reactor 3.

[0051] At least one temperature-controlled raw material gas conveying branch line 104 is connected in parallel on the temperature-controlled raw material gas conveying line 101 to convey part or all of the raw material mixed gas around the insulated temperature-regulating heat exchanger 2.

[0052] Each of the 2nd to nth adiabatic reaction units includes a feed ratio controller A5; The outlets of the first to n-1th stage adiabatic reactors 1 are connected to the feed inlet of the next stage adiabatic reactor 1 via syngas conveying line 105. The syngas conveying line 105 is connected to the feed ratio controller A5 via a pipeline, which is used to add vaporized aniline to the syngas after the reaction. The syngas delivery line 105 is connected to the next-level temperature-controlled raw material gas delivery line 101.

[0053] At least one temperature-controlled self-heating reaction raw material gas conveying branch line 106 is connected in parallel on the inlet pipeline 103 of the self-heating reactor to convey part or all of the reaction synthesis gas around the self-heating temperature-regulating heat exchanger 4; the self-heating reactor 3 is also provided with a circulation line 107. The self-heating reaction unit also includes a feed ratio controller B6; the outlet of each adiabatic reactor 1 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline, and the feed ratio controller B6 is connected to the inlet pipeline 103 of the self-heating reactor via a pipeline.

[0054] The wide-load adaptive N-methylaniline synthesis system also includes a cooler 7, a gas-liquid separator 8, and a distillation column 9 connected sequentially from the self-heating reactor 3; The self-heating reactor 3 and the cooler 7 are connected by a crude product gas conveying line 108. The liquid phase outlet of the gas-liquid separator 8 is connected to the raw material inlet of the distillation column 9 for distillation of the crude N-methylaniline product separated by gas-liquid separation; The gas phase outlet of gas-liquid separator 8 is connected to an external hydrogen purification system.

[0055] Each pipeline in the system is equipped with a valve. By opening and closing the valve and adjusting its opening degree, the process flow can be controlled, process parameters can be adjusted, and system switching can be achieved.

[0056] This embodiment 6 presents a more preferred technical solution based on embodiment 5. Specifically, valves are installed on each pipeline of the system. By opening and closing the valves and adjusting their opening degree, the process flow, process parameters, and system switching can be controlled. This embodiment 6, by configuring valves throughout the system pipelines, achieves flexible and precise control over the process flow, operating parameters, and operating modes, thereby significantly improving the system's adaptability to different production loads and the overall stability of operation.

[0057] Example 7 This embodiment discloses the wide-load adaptive N-methylaniline synthesis process of the present invention, which is implemented using the system of Example 6, where n = 2. The synthesis process flow of this embodiment is attached. Figure 2 As shown, the specific steps include the following: The raw material mixture formed by the vaporized methanol and aniline is divided into two streams. The main part enters the first-stage adiabatic reactor for reaction, while the remaining part is temperature-regulated by the first-stage adiabatic temperature-regulating heat exchanger and then injected into the bed space of the first-stage adiabatic reactor through the first-stage temperature-controlled raw material gas delivery line to participate in subsequent reactions. The synthesis gas output from the first-stage adiabatic reactor is mixed with vaporized aniline added through the second-stage feed ratio controller A to adjust the feed ratio. The mixed gas is divided into two streams. The main part enters the second-stage adiabatic reactor to continue the reaction, while the remaining part is temperature-regulated by the second-stage adiabatic temperature-regulating heat exchanger and then injected into the bed between the beds of the second-stage adiabatic reactor through the second-stage temperature-controlled feed gas delivery line to participate in subsequent reactions. The synthesis gas output from the second-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The mixed gas is then regulated by a self-heating temperature-regulating heat exchanger and enters the self-heating reactor for further alkylation reaction. The synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

[0058] Example 8 This embodiment discloses the wide-load adaptive N-methylaniline synthesis process of the present invention, which is implemented using the system of Example 6, where n=2. The synthesis process flow of this embodiment is attached. Figure 3 As shown, the specific steps include the following: The raw material mixture formed by the vaporized methanol and aniline is divided into two streams. The main part enters the first-stage adiabatic reactor for reaction, while the remaining part is temperature-regulated by the first-stage adiabatic temperature-regulating heat exchanger and then injected into the bed space of the first-stage adiabatic reactor through the first-stage temperature-controlled raw material gas delivery line to participate in subsequent reactions. The synthesis gas output from the first-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The mixed gas is then conditioned by a self-heating temperature-regulating heat exchanger and enters the self-heating reactor for further alkylation reaction. The second-stage adiabatic reaction unit was disconnected from the synthesis system, and the catalyst was replaced online. Preferably, the synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

[0059] Example 9 This embodiment discloses the wide-load adaptive N-methylaniline synthesis process of the present invention, which is implemented using the system of Example 6, where n=2. The synthesis process flow of this embodiment is attached. Figure 4 As shown, the specific steps include the following: The raw material mixture formed by mixing vaporized methanol and aniline is fed into the first-stage adiabatic reactor and the second-stage adiabatic reactor for reaction. Simultaneously, a portion of the raw material mixture is fed into the bed space of the first-stage adiabatic reactor after its temperature is regulated by the first-stage adiabatic temperature-regulating heat exchanger and the first-stage temperature-controlled raw material gas delivery branch line. A portion of the raw material mixture is also fed into the bed space of the second-stage adiabatic reactor after its temperature is regulated by the second-stage adiabatic temperature-regulating heat exchanger and the second-stage temperature-controlled raw material gas delivery branch line. The synthesis gas output from the first-stage adiabatic reactor and the synthesis gas output from the second-stage adiabatic reactor are mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The resulting mixed gas enters the self-heating reactor through the self-heating temperature control heat exchanger and the inlet pipeline of the self-heating reactor to continue the alkylation reaction. The synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

[0060] Example 10 This embodiment discloses the wide-load adaptive N-methylaniline synthesis process of the present invention, which is implemented using the system of Example 6, where n=2. The synthesis process flow of this embodiment is attached. Figure 2 As shown, the specific steps include the following: The raw material mixture formed by mixing vaporized methanol and aniline is divided into two streams. The main part enters the first-stage adiabatic reactor for reaction, while the remaining part is temperature-regulated by the first-stage adiabatic temperature-regulating heat exchanger and then injected into the bed space of the first-stage adiabatic reactor through the first-stage temperature-controlled raw material gas delivery line to participate in subsequent reactions. The synthesis gas output from the first-stage adiabatic reactor is mixed with vaporized aniline added through the second-stage feed ratio controller A to adjust the feed ratio. The mixed gas is divided into two streams. The main part enters the second-stage adiabatic reactor to continue the reaction, while the remaining part is temperature-regulated by the second-stage adiabatic temperature-regulating heat exchanger and then injected into the bed between the beds of the second-stage adiabatic reactor through the second-stage temperature-controlled feed gas delivery line to participate in subsequent reactions. The synthesis gas output from the second-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The mixed gas is then conditioned by a self-heating temperature-regulating heat exchanger before entering the self-heating reactor to continue the alkylation reaction. The self-heating reactor is filled with a portion of methanol cracking catalyst to produce hydrogen as a byproduct during the reaction. The synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

[0061] The synthesis process of Example 7 was used for production, taking a production capacity of 5000 tons / year of N-methylaniline as an example, with the following parameters: Methanol at 200℃ and a flow rate of ~725 kg / h and aniline at 200℃ and a flow rate of ~600 kg / h are mixed and then sequentially fed into an adiabatic reactor and a self-heating reactor connected in series for reaction. After cooling, the mixture is sent for distillation to obtain N-methylaniline with a flow rate of ~630 kg / h. The product quality meets the superior grade indicators in HG / T 3409-2010.

[0062] The synthesis process of Example 7 was used for production, taking a production capacity of 10,000 tons / year of N-methylaniline as an example, with the following parameters: Methanol at 210℃ and a flow rate of ~1565 kg / h and aniline at 210℃ and a flow rate of ~1200 kg / h are mixed in the gas phase and fed into a series of adiabatic reactors and self-heating reactors. After cooling, the mixture is sent for distillation to obtain N-methylaniline with a flow rate of ~1255 kg / h. The product quality meets the superior grade indicators in HG / T 3409-2010.

[0063] The synthesis process of Example 7 was used for production, taking a production capacity of 20,000 tons / year of N-methylaniline as an example, with the following parameters: Methanol and aniline are continuously mixed at 220℃ and a flow rate of ~3105 kg / h, and then continuously mixed at 220℃ and a flow rate of ~2400 kg / h. The mixture is then fed into a series of adiabatic reactors and an autothermal reactor for reaction. After cooling, the mixture is distilled to obtain N-methylaniline at a flow rate of ~2505 kg / h. The product quality meets the superior grade standards in HG / T 3409-2010.

[0064] The synthesis process described in Example 9 was used for production, with an N-methylaniline production capacity of 50,000 tons / year as an example. The parameters are as follows: Methanol at 230℃ and a flow rate of ~8105 kg / h and aniline at 230℃ and a flow rate of ~6000 kg / h are mixed in the gas phase and then fed into a reactor. Two-stage adiabatic reactors are connected in parallel and in series with a self-heating reactor. The synthesis gas is cooled and then sent for distillation to obtain N-methylaniline with a flow rate of ~6250 kg / h. The product quality meets the superior grade indicators in HG / T 3409-2010.

[0065] The above description is merely a preferred embodiment of the invention and does not constitute any limitation on the invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments based on the technical essence of the invention and within the spirit and principles of the invention shall still fall within the protection scope of the invention's technical solution.

Claims

1. A wide-load adaptive N-methylaniline synthesis system, characterized in that, include: There are n adiabatic reaction units and one autothermal reaction unit, where n is an integer greater than or equal to 2; Each of the aforementioned adiabatic reaction units includes an adiabatic reactor (1), a temperature-controlled raw material gas delivery line (101), and an adiabatic temperature-regulating heat exchanger (2); the raw material inlet of the adiabatic reactor (1) is connected to the raw material mixed gas delivery line (102) via a pipeline, the inlet of the temperature-controlled raw material gas delivery line (101) is connected to the raw material mixed gas delivery line (102), and its outlet is connected to the reaction bed of the adiabatic reactor (1); the adiabatic temperature-regulating heat exchanger (2) is installed on the temperature-controlled raw material gas delivery line (101); the outlets of the adiabatic reactors (1) from the first to the (n-1)th stage are respectively connected to the raw material inlet of the next stage adiabatic reactor (1) via pipelines. The self-heating reaction unit includes a self-heating reactor (3), a self-heating reactor inlet pipeline (103), and a self-heating temperature regulating heat exchanger (4). The self-heating temperature regulating heat exchanger (4) is installed on the self-heating reactor inlet pipeline (103). The self-heating reactor inlet pipeline (103) is connected to each adiabatic reactor (1) via pipelines. A crude product gas delivery line (108) is connected to the outlet of the self-heating reactor (3). At least one temperature-controlled raw material gas conveying branch line (104) is connected in parallel on the temperature-controlled raw material gas conveying line (101) to convey part or all of the raw material mixed gas around the insulated temperature-regulating heat exchanger (2). Each of the 2nd to nth adiabatic reaction units includes a feed ratio controller A (5); The outlets of the first to n-1th stage adiabatic reactors (1) are connected to the feed inlet of the next stage adiabatic reactor (1) via a syngas delivery line (105). The syngas delivery line (105) is connected to the feed ratio controller A (5) via a pipeline, which is used to add vaporized aniline to the syngas after the reaction; At least one temperature-controlled self-heating reaction raw material gas delivery branch line (106) is connected in parallel on the inlet pipeline (103) of the self-heating reactor to deliver part or all of the reaction synthesis gas around the self-heating temperature-regulating heat exchanger (4). The self-heating reactor (3) is also equipped with a circulation line (107). The self-heating reaction unit also includes a feed ratio controller B (6); the outlet of each adiabatic reactor (1) is connected to the inlet pipeline (103) of the self-heating reactor via a pipeline, and the feed ratio controller B (6) is connected to the inlet pipeline (103) of the self-heating reactor via a pipeline; The system also includes a cooler (7), a gas-liquid separator (8), and a distillation column (9) that are sequentially connected from the self-heating reactor (3).

2. The wide-load adaptive N-methylaniline synthesis system according to claim 1, characterized in that, The syngas delivery line (105) is connected to the next-level temperature-controlled raw material gas delivery line (101).

3. The wide-load adaptive N-methylaniline synthesis system according to claim 1, characterized in that, The self-heating reactor (3) and the cooler (7) are connected by a crude product gas conveying line (108).

4. The wide-load adaptive N-methylaniline synthesis system according to claim 1, characterized in that, The liquid outlet of the gas-liquid separator (8) is connected to the raw material inlet of the distillation column (9) for distillation of the crude N-methylaniline product separated by gas-liquid separation.

5. The wide-load adaptive N-methylaniline synthesis system according to claim 1, characterized in that, The gas phase outlet of the gas-liquid separator (8) is connected to the hydrogen purification system outside the boundary.

6. The wide-load adaptive N-methylaniline synthesis system according to claim 1, characterized in that, Each pipeline in the system is equipped with a valve. By opening and closing the valve and adjusting its opening degree, the process flow can be controlled, process parameters can be adjusted, and system switching can be achieved.

7. A wide-load adaptive N-methylaniline synthesis process, characterized in that, The system implementation according to any one of claims 1-6, wherein n=2, includes the following steps: The raw material mixture formed by the vaporized methanol and aniline is divided into two streams. The main part enters the first-stage adiabatic reactor for reaction, while the remaining part is temperature-regulated by the first-stage adiabatic temperature-regulating heat exchanger and then injected into the bed space of the first-stage adiabatic reactor through the first-stage temperature-controlled raw material gas delivery line to participate in subsequent reactions. The synthesis gas output from the first-stage adiabatic reactor is mixed with vaporized aniline added through the second-stage feed ratio controller A to adjust the feed ratio. The mixed gas is divided into two streams. The main part enters the second-stage adiabatic reactor to continue the reaction, while the remaining part is temperature-regulated by the second-stage adiabatic temperature-regulating heat exchanger and then injected into the bed between the beds of the second-stage adiabatic reactor through the second-stage temperature-controlled feed gas delivery line to participate in subsequent reactions. The synthesis gas output from the second-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The mixed gas is then conditioned by a self-heating temperature-regulating heat exchanger before entering the self-heating reactor for further alkylation reaction.

8. The wide-load adaptive N-methylaniline synthesis process according to claim 7, characterized in that, The synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

9. A wide-load adaptive N-methylaniline synthesis process, characterized in that, The system implementation according to any one of claims 1-6, wherein n=2, includes the following steps: The raw material mixture formed by the vaporized methanol and aniline is divided into two streams. The main part enters the first-stage adiabatic reactor for reaction, while the remaining part is temperature-regulated by the first-stage adiabatic temperature-regulating heat exchanger and then injected into the bed space of the first-stage adiabatic reactor through the first-stage temperature-controlled raw material gas delivery line to participate in subsequent reactions. The synthesis gas output from the first-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The mixed gas is then conditioned by a self-heating temperature-regulating heat exchanger and enters the self-heating reactor for further alkylation reaction. The second-stage adiabatic reaction unit is disconnected from the synthesis system, and the catalyst is replaced online.

10. The wide-load adaptive N-methylaniline synthesis process according to claim 9, characterized in that, The synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

11. A wide-load adaptive N-methylaniline synthesis process, characterized in that, The system implementation according to any one of claims 1-6, wherein n=2, includes the following steps: The raw material mixture formed by mixing vaporized methanol and aniline is fed into the first-stage adiabatic reactor and the second-stage adiabatic reactor for reaction. At the same time, part of the raw material mixture is fed into the bed space of the first-stage adiabatic reactor after the temperature is regulated by the first-stage adiabatic temperature-regulating heat exchanger and the first-stage temperature-controlled raw material gas delivery branch line to participate in subsequent reactions. And part of the raw material mixture is fed into the bed space of the second-stage adiabatic reactor after the temperature is regulated by the second-stage adiabatic temperature-regulating heat exchanger and the second-stage temperature-controlled raw material gas delivery branch line to participate in subsequent reactions. The synthesis gas output from the second-stage adiabatic reactor is mixed with vaporized aniline added through the feed ratio controller B to adjust the feed ratio. The resulting mixed gas enters the self-heating reactor sequentially through the self-heating temperature-regulating heat exchanger and the inlet pipeline of the self-heating reactor to continue the alkylation reaction.

12. The wide-load adaptive N-methylaniline synthesis process according to claim 11, characterized in that, The synthesis gas output from the self-heating reactor is cooled by a cooler and then enters a gas-liquid separator to separate crude N-methylaniline product and hydrogen-rich tail gas. The crude N-methylaniline product is fed into a distillation column for purification to obtain the N-methylaniline product; the hydrogen-rich tail gas is sent outside the boundary for hydrogen purification treatment.

13. A wide-load adaptive N-methylaniline synthesis process according to any one of claims 7-11, characterized in that, The self-heating reactor is filled with a portion of methanol cracking catalyst to produce hydrogen as a byproduct during the reaction.

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