A polymerization inhibition anti-coking ammoniation reactor

Abstract

The application discloses a polymerization inhibition and anti-coking ammoniation reactor, wherein gas raw materials are tangentially fed in a mixing section; a first separation section is composed of a plurality of coaxially arranged annular surfaces which are nested one above another; a catalyst outlet is arranged at the bottom between the bottom end of each annular surface and the adjacent annular surface; a baffle is arranged at the bottom of a second separation section, the outer edge of the baffle is connected with the side wall of the second separation section, a rising hole is arranged in the center of the baffle, the top end of the annular surface is connected with the edge of the rising hole, a product outlet is arranged around the rising hole on the baffle, a guide plate which is tangentially connected with the product outlet is arranged between the product outlet and the rising hole, a plurality of guide strips are arranged on the inner wall of the second separation section, and the inclination direction of the gap between the guide strips is consistent with the feeding direction of the gas raw materials. The application has the characteristics of efficient inhibition of side reactions, catalyst deactivation resistance, energy efficient utilization and energy saving in catalyst regeneration, and can significantly improve the reaction selectivity and production efficiency, and can significantly save energy and reduce emissions in both the reaction stage and the catalyst regeneration stage.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of reactors, and specifically relates to a polymerization inhibition and anti-coking ammoniation reactor capable of realizing catalyst grading recovery and by-product separation, which can significantly reduce energy consumption and is suitable for ammoniation reactions using caprolactam solution generated by liquid-phase rearrangement of cyclohexanone oxime in fuming sulfuric acid as raw material. BACKGROUND

[0002] 6-Aminocapronitrile is an important intermediate for the production of nylon 66, and in its industrial production process, the liquid-phase rearrangement product of cyclohexanone oxime (caprolactam) is often used as the main raw material to generate 6-aminocapronitrile through an ammoniation reaction. However, the existing ammoniation reaction equipment still has the following key problems in actual production:

[0003] Catalyst is prone to coking and deactivation, and is difficult to recycle: In a high-temperature ammoniation reaction environment, the catalyst surface is prone to coking due to the polymerization reaction of by-products, which leads to rapid decline in catalyst activity and makes it difficult to maintain efficient reaction. At the same time, the regeneration process of the coked catalyst is complex and costly, directly affecting the economy of production.

[0004] It is difficult to efficiently separate polymer by-products: During the ammoniation reaction process, polymer by-products are easily generated. These by-products not only affect the purity of the target product, but also can block the equipment, leading to a decrease in equipment operating efficiency or frequent shutdown for cleaning, increasing the complexity and cost of production.

[0005] Low utilization efficiency of reaction heat: The ammoniation reaction is a strong exothermic reaction, but the utilization of reaction heat in existing equipment is low. Usually, the heat is directly dissipated through cooling, causing energy waste. At the same time, the uneven distribution of reaction temperature in the tower can easily cause side reactions or reduce the selectivity of the target product.

[0006] In view of the above problems, a new type of reactor is developed to optimize gas-liquid mixing, catalyst grading recovery, by-product separation, and heat energy utilization, etc., to realize efficient control of the entire ammoniation reaction process, which has become an important technical requirement to improve the efficiency of 6-aminocapronitrile production. SUMMARY

[0007] In view of the problems of catalyst coking and deactivation, low recovery and utilization efficiency, high regeneration cost, and difficulty in accurately controlling the reaction temperature in the prior art, the present application proposes a polymerization inhibition and anti-coking ammoniation reactor. Through the innovative design of the catalyst grading recovery system, heat energy recovery and recycling system, and by-product efficient separation device, the ammoniation reaction process is comprehensively optimized, the heat energy utilization rate is improved, the energy consumption for by-product separation is reduced, and the energy consumption for catalyst regeneration is reduced.

[0008] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0009] An anti-polymerization and anti-coking ammoniation reactor is disclosed, wherein the reaction chamber of the reactor comprises, from bottom to top, a mixing section, a first separation section, and a second separation section, and the cross-section of the reaction chamber is circular.

[0010] The liquid feed inlet is located at the top of the mixing section, and the gas feed inlet is located on the side wall of the mixing section, with the gas feed direction tangent to the mixing section. A material outlet is located at the top of the reaction chamber.

[0011] The sidewall of the first separation section is composed of several coaxially arranged annular surfaces nested vertically. The top diameter of each annular surface is smaller than its bottom diameter, and the top of each annular surface is higher than the bottom of the adjacent annular surface above it. A catalyst outlet is provided at the bottom of the gap between the bottom of each annular surface and the adjacent annular surface below it.

[0012] The lowest annular surface extends downward to form the sidewall of the mixing section.

[0013] A baffle is horizontally installed at the bottom of the second separation section. The outer edge of the baffle engages with the side wall of the second separation section. A rising hole is formed in the center of the baffle, and the top of the highest annular surface connects to the edge of the rising hole.

[0014] The baffle plate has several product outlets around the rising hole. A guide plate with its bottom connected to the baffle plate is erected between the product outlets and the rising hole, and the guide plate is tangentially connected to the product outlets.

[0015] The inner wall of the second separation section is fitted with several parallel guide strips, with inclined gaps between the guide strips. The inclination direction is consistent with the feeding direction of the gaseous raw material from bottom to top. That is, when the gas is fed counterclockwise in the mixing section, the gaps at the guide strips are inclined counterclockwise from bottom to top, thus conforming to the rotation direction of the gas-liquid mixture. The reverse is also true.

[0016] Furthermore, the lower edge of the guide strip is above the upper edge of the guide plate.

[0017] Furthermore, the product outlet is connected to the inner wall of the second separation section, and the product outlet is uniformly surrounding the rising hole in the circumferential direction.

[0018] Furthermore, a plurality of catalyst scrapers are vertically connected to the inner wall of the annular surface. Preferably, the catalyst scrapers are uniformly arranged circumferentially along the annular surface.

[0019] Furthermore, the annular surface is wrapped with a first heat exchange section, which is filled with a heat-insulating medium, and a heat exchange pipe is disposed within the heat-insulating medium.

[0020] Furthermore, the mixing section is externally wrapped with a second heat exchange section, which is filled with a heat-insulating medium, and a heat exchange pipe is installed within the heat-insulating medium.

[0021] Furthermore, the liquid raw material inlet is connected to a liquid distribution device, which is located above the center of the mixing section.

[0022] Furthermore, the inner wall of the mixing section is also provided with guide strips, and the guide strips are arranged in the same way as the second separation section.

[0023] Furthermore, the gas raw material inlet is connected to a gas injection pipe, through which the gas raw material is injected into the mixing section.

[0024] Furthermore, the gas feedstock inlet has multiple locations, and the gas feedstock inlet directions are all either counterclockwise or all clockwise.

[0025] Furthermore, a residue outlet is provided at the bottom of the reaction chamber.

[0026] Furthermore, the material outlet is connected to the unreacted liquid outlet via a heat exchanger, and the fresh gas inlet is connected to the gas feedstock inlet via the same heat exchanger.

[0027] Furthermore, the heat exchange medium outlet of the heat exchanger is connected to the heat exchange pipe.

[0028] Furthermore, the guide plate is arc-shaped.

[0029] Furthermore, the polymerization-inhibiting and coking-resistant ammoniation reactor is used for the ammoniation reaction of cyclohexanone oxime liquid-phase rearrangement products.

[0030] The anti-polymerization and anti-caking coking ammoniation reactor of this invention features a mixing section where the feed gas is tangentially fed and mixed with the liquid feedstock, causing the reactants to rise in a spiral flow. In the first separation section, the catalyst in good condition in the reactants is centrifuged in the lower half and recovered from the gaps between the annular surfaces of adjacent stages, significantly reducing the catalyst regeneration requirement. The upper half of the first separation section recovers the catalyst in poor condition, which is then processed by a separate, dedicated, low-energy regeneration system and reused. The nested design of multiple annular surfaces in the first separation section allows for the staged recovery of catalysts in different states, reducing catalyst regeneration energy consumption by more than half, significantly lowering production costs, and extending catalyst lifespan.

[0031] Secondly, this invention fully absorbs the exothermic reaction during the process through the heat exchange medium. The heat exchange medium first absorbs the heat from the 6-aminohexanonitrile and unreacted ammonia in the gas phase exiting the top of the tower, achieving the condensation of 6-aminohexanonitrile and preheating the fresh ammonia. Subsequently, the heat exchange medium flows through the heat exchange pipes into the first separation section and mixing section, further absorbing the exothermic reaction and achieving precise temperature control and uniform distribution within the tower. This design effectively avoids side reactions and catalyst deactivation caused by localized overheating, while reducing the demand for external energy and improving overall energy utilization efficiency.

[0032] In addition, the second separation section adopts an optimized design to effectively separate the polymers and heavy components generated during the reaction process, preventing them from adhering to the inner wall of the equipment or clogging the reactor, thus ensuring the stability and continuity of the reaction process.

[0033] Preferably, the heat exchange medium is one or more of ammonia, water, mineral oil, silicone oil, and synthetic oil.

[0034] The beneficial effects of the invention are:

[0035] This invention addresses the problems of easy catalyst coking and deactivation, low recycling efficiency, high regeneration cost, and difficulty in accurately controlling the reaction temperature in existing technologies. It proposes an anti-polymerization and anti-coking ammoniation reactor that can be used for the ammoniation of cyclohexanone oxime liquid-phase rearrangement products. Through the innovative design of a catalyst staged recovery system, a heat energy recovery and recycling system, and a high-efficiency by-product separation device, the ammoniation reaction process is comprehensively optimized, and the overall production energy consumption is reduced. Attached Figure Description

[0036] Fig. 1 This is a schematic diagram of the anti-polymerization and anti-coking ammonialation reactor described in this invention.

[0037] Fig. 2 This is a top view of the baffle structure.

[0038] Fig. 3 This is a three-dimensional structural diagram of the baffle and guide vane.

[0039] Wherein, 1 is the mixing section, 2 is the first separation section, 3 is the second separation section, 4 is the liquid distribution device, 5 is the catalyst outlet, 6 is the gas feed inlet, 7 is the riser hole, 8 is the guide strip, 9 is the catalyst scraper, 10 is the heat exchange pipe, 11 is the product outlet, 12 is the guide plate, 13 is the baffle, 14 is the fresh gas inlet, 15 is the heat exchange medium inlet, 16 is the unreacted liquid outlet, 17 is the heat exchange medium outlet, 18 is the heat exchanger, 19 is the reactor residue outlet, 20 is the insulation medium, and 21 is the gas injection pipe. Detailed Implementation

[0040] like Figs. 1-3The diagram illustrates an anti-polymerization and anti-coking ammonialation reactor. The reactor's reaction chamber, from bottom to top, comprises a mixing section 1, a first separation section 2, and a second separation section 3. The reaction chamber has a circular cross-section. A liquid feed inlet 6 is located at the top of the mixing section, and a gas feed inlet 6 is located on the side wall of the mixing section, with the gas feed direction tangential to the mixing section. A material outlet is located at the top of the reaction chamber. The side wall of the first separation section 2 is composed of several coaxially arranged nested annular surfaces. The top diameter of each annular surface is smaller than its bottom diameter, and the top of each annular surface is higher than the bottom of its adjacent annular surface. A catalyst outlet 5 is located at the bottom of the gap between the bottom of each annular surface and its adjacent annular surface below it. The lower annular surface extends downward to form the sidewall of the mixing section 1. A baffle 13 is horizontally arranged at the bottom of the second separation section 3. The outer edge of the baffle 13 is joined to the sidewall of the second separation section 3. A rising hole 7 is opened in the center of the baffle 13. The top of the highest annular surface is connected to the edge of the rising hole 7. Several product outlets 11 are opened on the baffle 13 around the rising hole 7. A guide plate 12 with its bottom connected to the baffle 13 is erected between the product outlets 11 and the rising hole 7. The guide plate 12 is tangentially connected to the product outlets 11. Several parallel guide strips 8 are attached to the inner wall of the second separation section 3. An inclined gap is left between the guide strips 8. The inclined direction is consistent with the feeding direction of the gas raw material from bottom to top.

[0041] The lower edge of the guide strip 8 is above the upper edge of the guide plate 12.

[0042] The product outlet 11 is connected to the inner wall of the second separation section 3, and the product outlet 11 is uniformly surrounding the rising hole 7 in the circumferential direction.

[0043] A plurality of catalyst scrapers 9 are vertically connected to the inner wall of the annular surface. Preferably, the catalyst scrapers 9 are uniformly arranged along the circumference of the annular surface.

[0044] The annular surface is surrounded by a first heat exchange section, which is filled with a heat-insulating medium 20, and a heat exchange pipe 10 is disposed within the heat-insulating medium 20.

[0045] The mixing section 1 is externally wrapped with a second heat exchange section, which is filled with a heat-insulating medium, and a heat exchange pipe is installed in the heat-insulating medium.

[0046] The liquid raw material inlet is connected to the liquid distribution device 4, which is located above the center of the mixing section 1.

[0047] The inner wall of the mixing section 1 is also provided with guide strips 8, and the guide strips 8 are arranged in the same way as the second separation section.

[0048] The gas raw material inlet 6 is connected to the gas injection pipe 21, and gas is injected into the mixing section 1 through the gas injection pipe 21.

[0049] There are multiple gas feed inlets 6, and the gas feed directions are all either counterclockwise or all clockwise.

[0050] The bottom of the reaction chamber is provided with a residue outlet 19.

[0051] The material outlet is connected to the unreacted liquid outlet 16 via heat exchanger 18, and the fresh gas inlet 14 is connected to the gas raw material inlet 6 via heat exchanger 18.

[0052] The heat exchange medium outlet 17 of the heat exchanger 18 is connected to the heat exchange pipe 10.

[0053] The guide plate 12 is arc-shaped.

[0054] Example 1

[0055] This apparatus was used to perform the ammoniation reaction of cyclohexanone oxime liquid-phase rearrangement products.

[0056] The caprolactam solution obtained from the cyclohexanone oxime rearrangement process was used as the feed solution, and a comparative experiment was conducted between a conventional fluidized bed reactor and the ammoniation reactor of this invention. The operating conditions are shown in Table 1, and the reaction results are compared in Table 2.

[0057] Table 1 Operating conditions for Example 1

[0058] .

[0059] Table 2 Comparison of reaction results

[0060] .

[0061] Example 2

[0062] This apparatus was used to perform the ammoniation reaction of cyclohexanone oxime liquid-phase rearrangement products.

[0063] The caprolactam solution obtained from the cyclohexanone oxime rearrangement process was used as the feed solution, and a comparative experiment was conducted between a conventional fluidized bed reactor and the ammoniation reactor of this invention. The operating conditions are shown in Table 3, and the reaction results are compared in Table 4.

[0064] Table 3 Operating conditions for Example 2

[0065] .

[0066] Table 4 Comparison of reaction results

[0067] .

[0068] Example 3

[0069] This apparatus was used to perform the ammoniation reaction of cyclohexanone oxime liquid-phase rearrangement products.

[0070] The caprolactam solution obtained from the cyclohexanone oxime rearrangement process was used as the feed solution, and a comparative experiment was conducted between a conventional fluidized bed reactor and the ammoniation reactor of this invention. The operating conditions are shown in Table 5, and the reaction results are compared in Table 6.

[0071] Table 5 Operating conditions for Example 3

[0072] .

[0073] Table 6 Comparison of reaction results

[0074] .

[0075] Example 4

[0076] This apparatus was used to perform the ammoniation reaction of cyclohexanone oxime liquid-phase rearrangement products.

[0077] The caprolactam solution obtained from the cyclohexanone oxime rearrangement process was used as the feed solution, and a comparative experiment was conducted between a conventional fluidized bed reactor and the ammoniation reactor of this invention. The operating conditions are shown in Table 7, and the reaction results are compared in Table 8.

[0078] Table 7 Operating conditions for Example 4

[0079] .

[0080] Table 8 Comparison of reaction results

[0081] .

Claims

1. A polymerization inhibitor anti-coking ammoniation reactor characterized by, The reaction cavity of the polymerization inhibition and anti-coking ammoniation reactor from bottom to top is sequentially mixed section (1), first separation section (2) and second separation section (3), and the cross section of the reaction cavity is circular, The liquid raw material inlet is arranged at the top of the mixed section, the gas raw material inlet (6) is arranged on the side wall of the mixed section, and the feeding direction of the gas raw material is tangent to the mixed section, and the material outlet is arranged at the top of the reaction cavity, The side wall of the first separation section (2) is composed of a plurality of coaxially arranged annular surfaces nested from top to bottom, the top end diameter of each annular surface is smaller than the bottom end diameter, the top end of each annular surface is higher than the bottom end of the adjacent annular surface above it, and the bottom of the gap between the bottom end of each annular surface and the adjacent annular surface below it is provided with a catalyst outlet (5), The lowest annular surface extends downward to form the side wall of the mixed section (1), The bottom of the second separation section (3) is horizontally provided with a baffle (13), the outer edge of the baffle (13) is connected with the side wall of the second separation section (3), the center of the baffle (13) is provided with a rising hole (7), and the top end of the highest annular surface is connected with the edge of the rising hole (7), A plurality of product outlets (11) are arranged around the rising hole (7) on the baffle (13), a guide plate (12) connected with the baffle (13) is vertically arranged between the product outlet (11) and the rising hole (7), and the guide plate (12) is tangentially connected with the product outlet (11), The inner wall of the second separation section (3) is provided with a plurality of parallel guide strips (8), and the guide strips (8) are provided with inclined gaps therebetween, and the inclined direction is consistent with the feeding direction of the gas raw material from bottom to top.

2. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The product outlet (11) is connected with the inner wall of the second separation section (3).

3. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The inner wall of the annular surface is vertically connected with a plurality of catalyst scrapers (9).

4. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The outer part of the annular surface is wrapped with a first heat exchange part, the first heat exchange part is filled with a heat preservation medium (20), and a heat exchange pipeline (10) is arranged in the heat preservation medium (20).

5. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The inner wall of the mixed section (1) is also provided with a guide strip (8), and the guide strip (8) is arranged in the same way as the second separation section.

6. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The gas raw material inlet (6) is connected with a gas injection pipe (21), and the gas raw material is injected into the mixed section (1) by the gas injection pipe (21).

7. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The gas raw material inlet (6) has a plurality of gas raw material inlets, and the feeding directions of the gas raw material inlets are counterclockwise or clockwise.

8. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The material outlet is connected with an unreacted liquid outlet (16) through a heat exchanger (18), and a fresh gas inlet (14) is connected with the gas raw material inlet (6) through the heat exchanger (18).

9. The polymerization inhibitor anti-coking ammoniation reactor of claim 1, wherein, The guide plate (12) is arc-shaped.

10. The polymerization inhibitor anti-coking ammoniation reactor according to any one of claims 1-9, wherein, The polymerization inhibition and anti-coking ammoniation reactor is used for the ammoniation reaction of cyclohexanone oxime liquid phase rearrangement product.

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