A crude cyclohexane processing apparatus

Abstract

This invention provides a crude cyclohexane processing apparatus, comprising a first pipeline, a second pipeline, a third pipeline, a cyclohexane storage tank, a hydrotreated naphtha storage tank, a hydrotreated naphtha pump, a continuous reforming unit, and an aromatics complex. The input end of the first pipeline is connected to an external crude cyclohexane pipeline, and the output end of the first pipeline is connected to the input end of the cyclohexane storage tank. The input end of the second pipeline is connected to an external hydrotreated naphtha pipeline. The first and second pipelines are connected via the third pipeline. The output end of the second pipeline is connected to the input end of the hydrotreated naphtha storage tank, and the output end of the hydrotreated naphtha storage tank is connected to the input end of the hydrotreated naphtha pump. This invention uses a new pipeline to deliver crude cyclohexane to the hydrotreated naphtha tank, which is then pumped to the continuous reforming unit. Under the action of a catalyst, cyclohexane is dehydrogenated to benzene, producing hydrogen as a byproduct. The resulting product is then processed by the aromatics complex to produce qualified aromatics.

Description

Technical Field

[0001] This utility model relates to the field of cyclohexane utilization, and in particular to a crude cyclohexane processing apparatus. Background Technology

[0002] Cyclohexane is a saturated six-membered cycloalkanes, a colorless, volatile liquid with a gasoline-like odor at room temperature. It is a crucial raw material for the production of adipic acid, caprolactam, and nylon-6 and nylon-66. Industrially, cyclohexane is primarily produced through the hydrogenation of benzene. However, in the hydration process for cyclohexanol, cyclohexane is also produced as a byproduct in the form of "crude cyclohexane." Crude cyclohexane refers to the light oil phase obtained after condensation and oil-water separation during the cyclohexanol synthesis process. Besides containing 75–90% (wt) cyclohexane, it also contains impurities such as methylcyclopentane, cyclohexene, benzene, and water. Its complex composition and low purity usually result in it being sold directly as a low-value byproduct.

[0003] To improve the purity of crude cyclohexane, existing technologies generally employ a "distillation-hydrogenation-re-distillation" refining route: First, crude cyclohexane is fed into a light component column, where C5 and C6 light hydrocarbons and water are removed at the top. The bottom product is then passed through a hydrogenation reactor, where unsaturated components such as cyclohexene and benzene are hydrogenated to saturation under the action of Ni / Al2O3 or Pd / Al2O3 catalysts. It then enters a refined cyclohexane column, where further separation is achieved under conditions of a reflux ratio of 5–10 and a top temperature of approximately 80°C, ultimately yielding cyclohexane with a purity ≥99.5%. To reduce energy consumption, some units also employ heat pump distillation, partitioned-wall distillations, or thermal coupling technologies. Simultaneously, to prevent cyclohexane-water azeotropy, a phase separator or molecular sieve drying system is required at the top of the column. The entire refining process involves numerous equipment and complex control, necessitating the independent construction of hydrogenation, distillation, and utility systems.

[0004] However, the above-mentioned refining process has the following obvious shortcomings: long process and high equipment investment, requiring the construction of new hydrogenation reactors, high-pressure circulating hydrogen systems, multi-tower distillation and drying units, with investments often reaching tens of millions of yuan; high energy consumption and high operating costs, the hydrogenation reaction needs to be maintained at 2.0-3.0 MPa and 150-200℃, and the steam consumption of the reboiler in the distillation tower exceeds 1.2t steam / t product, resulting in high overall energy consumption; refined cyclohexane is mainly used in solvent or adipic acid units, while the output of crude cyclohexane by-product is relatively small, making it difficult to achieve economies of scale and difficult to sell; therefore, there is an urgent need for a new method that requires less investment, has low energy consumption, and can convert crude cyclohexane into higher-value products. Utility Model Content

[0005] This invention provides a crude cyclohexane processing device, which solves the problem of low conversion value of existing crude cyclohexane.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A crude cyclohexane processing unit includes a first pipeline, a second pipeline, a third pipeline, a cyclohexane storage tank, a hydrotreated naphtha storage tank, a hydrotreated naphtha pump, a continuous reforming unit, and an aromatics complex.

[0008] The input end of the first pipeline is connected to an external crude cyclohexane pipeline, and the output end of the first pipeline is connected to the input end of the cyclohexane storage tank. The input end of the second pipeline is connected to an external hydrotreated naphtha pipeline. The first and second pipelines are connected by a third pipeline. The output end of the second pipeline is connected to the input end of the hydrotreated naphtha storage tank. The output end of the hydrotreated naphtha storage tank is connected to the input end of the hydrotreated naphtha pump. The output end of the hydrotreated naphtha pump is connected to the input end of the continuous reforming unit. The output end of the continuous reforming unit is connected to the input end of the aromatics complex.

[0009] Furthermore, a flow regulating valve is provided on the third pipeline.

[0010] Furthermore, the first pipeline and the third pipeline, as well as the second pipeline and the third pipeline, are all connected by flanges through reserved interfaces.

[0011] Furthermore, the spacing between the reserved interfaces is less than or equal to 300 meters.

[0012] Furthermore, the hydrotreated naphtha storage tank is equipped with a static mixer.

[0013] Furthermore, the hydrotreated naphtha pump is a variable frequency centrifugal pump.

[0014] Furthermore, the aromatic hydrocarbon complex includes a benzene tower, a toluene tower, and a xylene tower.

[0015] The beneficial effects of this utility model are as follows:

[0016] This invention, through a simple modification of the pipeline, directly introduces low-value crude cyclohexane into an existing continuous reforming-aromatics complex, allowing the cyclohexane to undergo one-step dehydrogenation to convert it into benzene on a reforming catalyst. The benzene is then separated in the aromatics complex to obtain high-purity aromatic products. Compared with existing technologies, this invention has the following significant advantages:

[0017] This utility model only requires the addition of a DN50 to DN80 connecting pipe between the crude cyclohexane to the storage tank pipeline and the hydrotreated naphtha to the storage tank pipeline, utilizing the existing reserved interface, without the need to build new hydrotreating, distillation and public works facilities, thus saving investment;

[0018] The processing of crude cyclohexane relies entirely on the waste heat and pressure of existing reforming and aromatics complexes, requiring no additional steam, hydrogen, or cooling water. The energy consumption per ton of product is lower than that of traditional refining routes.

[0019] Cyclohexane is dehydrogenated to produce benzene, which is then further converted into high-value-added products such as PX and OX via an aromatics complex, increasing the overall value and providing a large market capacity and stable sales.

[0020] The crude cyclohexane feed rate can be flexibly adjusted within the range of 5–10 t / h, and the reforming unit load does not need to be adjusted, without affecting the original naphtha processing scheme; Attached Figure Description

[0021] To more clearly illustrate the embodiments of this utility model or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the device of this utility model.

[0023] Explanation of icon numbers:

[0024] 1. First pipeline; 2. Second pipeline; 3. Third pipeline; 4. Cyclohexane storage tank; 5. Hydrogenated naphtha storage tank; 6. Hydrogenated naphtha pump; 7. Continuous reforming unit; 8. Aromatics complex unit. Detailed Implementation

[0025] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this utility model or its application or use. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0029] In the description of this utility model, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0030] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0031] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0032] This utility model provides a technical solution: a crude cyclohexane processing apparatus, such as... Figure 1 As shown, it includes a first pipeline 1, a second pipeline 2, a third pipeline 3, a cyclohexane storage tank 4, a hydrotreated naphtha storage tank 5, a hydrotreated naphtha pump 6, a continuous reforming unit 7, and an aromatics complex 8.

[0033] The input end of the first pipeline 1 is connected to an external crude cyclohexane pipeline, and the output end of the first pipeline 1 is connected to the input end of the cyclohexane storage tank 4. The input end of the second pipeline 2 is connected to an external hydrotreated naphtha pipeline. The first pipeline 1 and the second pipeline 2 are connected by a third pipeline 3. The output end of the second pipeline 2 is connected to the input end of the hydrotreated naphtha storage tank 5. The output end of the hydrotreated naphtha storage tank 5 is connected to the input end of the hydrotreated naphtha pump 6. The output end of the hydrotreated naphtha pump 6 is connected to the input end of the continuous reforming unit 7. The output end of the continuous reforming unit 7 is connected to the input end of the aromatics complex 8. The continuous reforming unit 7 operates under certain temperature and pressure conditions, using a platinum (Pt) catalyst to rearrange the hydrocarbon molecules in the feedstock naphtha, converting cycloalkanes and alkanes into aromatics or isoalkanes, while simultaneously generating some hydrogen.

[0034] Preferably, the third pipeline 3 is equipped with a flow regulating valve.

[0035] Preferably, the first pipeline 1 and the third pipeline 3, and the second pipeline 2 and the third pipeline 3 are all connected by flanges through reserved interfaces.

[0036] Preferably, the spacing between the reserved interfaces is less than or equal to 300 meters.

[0037] Preferably, the hydrotreated naphtha storage tank 5 is equipped with a static mixer.

[0038] Preferably, the hydrotreated naphtha pump 6 is a variable frequency centrifugal pump.

[0039] Preferably, the aromatic hydrocarbon complex 8 includes a benzene tower, a toluene tower, and a xylene tower.

[0040] This invention introduces a new pipeline to deliver crude cyclohexane to a hydrotreated naphtha tank, which is then pumped to a continuous reforming unit via a naphtha pump in the tank area. Under the action of a catalyst, cyclohexane is dehydrogenated into benzene, with hydrogen as a byproduct. The product is then processed by an aromatics complex to produce qualified aromatics.

[0041] The new pipeline connects the crude cyclohexane to the storage tank pipeline with the hydrotreated naphtha pipeline. The crude cyclohexane is sent to the hydrotreated naphtha storage tank via the new pipeline. After being pressurized by a pump, it passes through the continuous reforming unit and the aromatics complex unit to finally produce qualified aromatics products. The crude cyclohexane flow rate is 5-10 t / h and the temperature is ≤40℃.

[0042] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A crude cyclohexane processing apparatus characterized by: It includes the first pipeline (1), the second pipeline (2), the third pipeline (3), the cyclohexane storage tank (4), the hydrotreated naphtha storage tank (5), the hydrotreated naphtha pump (6), the continuous reforming unit (7), and the aromatics complex (8). The input end of the first pipeline (1) is connected to an external crude cyclohexane pipe, the output end of the first pipeline (1) is connected to the input end of the cyclohexane storage tank (4), the input end of the second pipeline (2) is connected to an external hydrotreated naphtha pipe, the first pipeline (1) and the second pipeline (2) are connected by a third pipeline (3), the output end of the second pipeline (2) is connected to the input end of the hydrotreated naphtha storage tank (5), the output end of the hydrotreated naphtha storage tank (5) is connected to the input end of the hydrotreated naphtha pump (6), the output end of the hydrotreated naphtha pump (6) is connected to the input end of the continuous reforming unit (7), and the output end of the continuous reforming unit (7) is connected to the input end of the aromatics complex (8).

2. The crude cyclohexane processing apparatus according to claim 1, characterized in that: The third pipeline (3) is equipped with a flow regulating valve.

3. The crude cyclohexane processing apparatus of claim 1, wherein: The first pipeline (1) and the third pipeline (3), and the second pipeline (2) and the third pipeline (3) are all connected by flanges through reserved interfaces.

4. The crude cyclohexane processing apparatus of claim 3, wherein: The spacing between the reserved interfaces is less than or equal to 300 meters.

5. The crude cyclohexane processing apparatus of claim 1, wherein: The hydrogenated naphtha storage tank (5) is equipped with a static mixer.

6. The crude cyclohexane processing apparatus of claim 1, wherein: The hydrogenated naphtha pump (6) is a variable frequency centrifugal pump.

7. The crude cyclohexane processing apparatus of claim 1, wherein: The aromatics complex (8) includes a benzene tower, a toluene tower and a xylene tower.

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