Methylcyclohexane separation and recovery device

Abstract

The utility model belongs to the resource recovery technical field relates to a methylcyclohexane separation and recovery device, including heavy separation tower, heavy separation tower top reflux pump, de -heavy tower, de -heavy tower reflux pump, product tank and naphtha pipeline, the tower top of heavy separation tower communicates with one end of heavy separation tower top reflux pump, the other end of heavy separation tower top reflux pump communicates with the tower side of heavy separation tower and the tower side of de -heavy tower respectively, the tower top of de -heavy tower communicates with the tower side of de -heavy tower and product tank respectively after de -heavy tower reflux pump. The utility model further realizes the efficient separation and recovery of methylcyclohexane by de -heavy tower, thereby reducing the content of methylcyclohexane in heavy separation tower kettle liquid, improving methylcyclohexane yield and raw material utilization, and avoiding direct economic loss, increasing the income.

Description

Technical Field

[0001] This utility model belongs to the field of separation and recovery technology, and relates to a methylcyclohexane separation and recovery device. Background Technology

[0002] Methylcyclohexane is an important aliphatic cyclic hydrocarbon, widely used in organic solvents, gasoline additives, and chemical intermediates. Its production process is primarily based on petrochemical raw materials, with the core route including the toluene hydrogenation reduction method. In actual production, the separation and purification of methylcyclohexane are necessary during its production and refining processes.

[0003] The existing method for separating and purifying methylcyclohexane involves the bottom liquid from the C7 removal column entering a heavy separation column. The methylcyclohexane fraction produced at the top of the heavy separation column contains impurities such as 2,5-dimethylcyclohexane, which are not only low in purity but also unstable. Therefore, the low-purity methylcyclohexane is passed into a solvent recovery column to separate the impurities, thereby purifying the methylcyclohexane and finally obtaining a methylcyclohexane product with a purity of ≥99.5%. Although existing technologies can improve the purity of methylcyclohexane products, the following problems exist: When using a solvent recovery tower for separation and purification, solvent consumption is high, and the yield of methylcyclohexane is low. This results in unrecovered methylcyclohexane entering the bottom liquid of the heavy separation tower. Measurements show that approximately 15% of the bottom liquid contains methylcyclohexane, making efficient recovery impossible and reducing raw material utilization. Furthermore, the bottom liquid is sold as naphtha, but since methylcyclohexane is more expensive than naphtha, selling the high-priced methylcyclohexane as low-priced naphtha results in direct economic losses. Utility Model Content

[0004] To address the technical problems of low methylcyclohexane yield, reduced raw material utilization, and direct economic losses in the production of methylcyclohexane using existing gravity separation towers, this invention provides a methylcyclohexane separation and recovery device.

[0005] This invention connects the top of the heavy separation tower to the heavy separation tower, and uses the heavy separation tower to achieve efficient separation and recovery of methylcyclohexane, thereby reducing the content of methylcyclohexane in the bottom liquid of the heavy separation tower, improving the yield of methylcyclohexane and the utilization rate of raw materials, avoiding direct economic losses, and increasing profits.

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

[0007] A methylcyclohexane separation and recovery unit includes a heavy separation tower, a heavy separation tower top reflux pump, a heavy separation tower de-heavy separation tower, a heavy separation tower reflux pump, a product tank, and a naphtha pipeline;

[0008] The top of the heavy separation tower is connected to one end of the heavy separation tower top reflux pump; the other end of the heavy separation tower top reflux pump is connected to the tower side of the heavy separation tower and the tower side of the de-heavy separation tower, respectively; the top of the de-heavy separation tower is connected to the tower side of the de-heavy separation tower and the product tank, respectively, after passing through the de-heavy separation tower reflux pump.

[0009] Further specified, a reflux control valve for the heavy separator is provided between the other end of the reflux pump at the top of the heavy separator and the side of the heavy separator; a feed control valve for the de-heavy separator is provided between the other end of the reflux pump at the top of the heavy separator and the side of the de-heavy separator.

[0010] Further specified, a de-weighting tower reflux control valve is provided between the de-weighting tower reflux pump and the tower side of the de-weighting tower; a de-weighting tower product control valve is provided between the de-weighting tower reflux pump and the product tank.

[0011] Further specified, a redistribution tank is provided between the top of the redistribution tower and the redistribution tower top reflux pump.

[0012] Further specified, a deweight removal tower reflux tank is provided between the top of the deweight removal tower and the deweight removal tower reflux pump.

[0013] Furthermore, the other end of the reflux pump at the top of the redistribution tower is also connected to the product tank.

[0014] Further specifying, a redistribution tower product control valve is installed between the other end of the redistribution tower top reflux pump and the product tank.

[0015] Furthermore, the methylcyclohexane separation and recovery unit also includes a naphtha pipeline and a naphtha transfer pump; the bottom of the heavy separation tower and the bottom of the de-heavy separation tower are both connected to the naphtha pipeline via the naphtha transfer pump.

[0016] Further specified, a control valve for the bottom of the heavy separation tower is provided between the bottom of the heavy separation tower and the naphtha transfer pump.

[0017] Further specified, a control valve for the bottom of the deweighting tower is provided between the bottom of the deweighting tower and the naphtha transfer pump.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] 1. In this invention, the top of the heavy separation column is connected to one end of the heavy separation column top reflux pump; the other end of the heavy separation column top reflux pump is connected to both the column side of the heavy separation column and the column side of the de-heavy separation column; the top of the de-heavy separation column, after passing through the de-heavy separation column reflux pump, is connected to both the column side of the de-heavy separation column and the product tank. By connecting the top of the heavy separation column to the column side of the de-heavy separation column, the low-purity methylcyclohexane component produced from the top of the heavy separation column is separated and purified using the de-heavy separation column. This ensures the purity of methylcyclohexane while increasing its yield, thereby reducing the methylcyclohexane content in the bottom liquid of the heavy separation column, significantly improving the utilization rate of raw materials, avoiding direct economic losses, and increasing profits.

[0020] 2. The other end of the reflux pump at the top of the heavy separation tower is connected to the tower side of the heavy separation tower; the top of the de-heavy separation tower is connected to the tower side of the de-heavy separation tower after passing through the de-heavy separation tower reflux pump, so that the top components of the heavy separation tower and the top components of the de-heavy separation tower are partially refluxed back to the corresponding towers for secondary mass transfer separation, thereby further improving the separation and recovery efficiency of methylcyclohexane.

[0021] 3. This invention includes a heavy separation column reflux tank between the top of the heavy separation column and the heavy separation column reflux pump, and a de-heavy separation column reflux tank between the top of the de-heavy separation column and the de-heavy separation column reflux pump. The heavy separation column reflux tank and the de-heavy separation column reflux tank act as buffers for the components separated from the top of the heavy separation column and the top of the de-heavy separation column, respectively, ensuring the operational stability of the entire device.

[0022] 4. This utility model, by setting up a reflux control valve for the heavy separation tower, a feed control valve for the de-heavy separation tower, and a reflux control valve for the de-heavy separation tower, facilitates the control of material reflux and conveying, and provides flexible operation. Attached Figure Description

[0023] Figure 1 The methylcyclohexane recovery device provided by this utility model;

[0024] Figure 2 This is a schematic diagram of the weight-removing tower structure;

[0025] in:

[0026] 10 - Heavy separation tower; 20 - Heavy separation tower reflux tank; 30 - Heavy separation tower top reflux pump; 40 - Naphtha transfer pump; 50 - De-heavy separation tower; 60 - De-heavy separation tower reflux tank; 70 - De-heavy separation tower reflux pump; 80 - Product tank; 90 - Reboiler;

[0027] 101 - Reflux control valve for heavy separation tower; 102 - Bottom control valve for heavy separation tower; 103 - Feed control valve for de-heavy separation tower; 104 - Product control valve for heavy separation tower; 105 - Reflux control valve for de-heavy separation tower; 106 - Product control valve for de-heavy separation tower; 107 - Bottom control valve for de-heavy separation tower. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0029] 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 this application. 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.

[0030] See Figure 1 In one possible embodiment of this utility model, the methylcyclohexane separation and recovery device includes a heavy separation tower 10, a heavy separation tower top reflux pump 30, a heavy separation tower 50, a heavy separation tower reflux pump 70, a product tank 80, and a naphtha pipeline.

[0031] Specifically, the top of the heavy separation tower 10 is connected to one end of the heavy separation tower top reflux pump 30; the other end of the heavy separation tower top reflux pump 30 is connected to the tower side of the heavy separation tower 10 and the tower side of the de-heavy separation tower 50 respectively; the top of the de-heavy separation tower 50 is connected to the tower side of the de-heavy separation tower 50 and the product tank 80 respectively after passing through the de-heavy separation tower reflux pump 70.

[0032] In one possible embodiment of this utility model, the methylcyclohexane separation and recovery device further includes a naphtha pipeline, and the bottom of the heavy separation tower 10 and the bottom of the de-heavy tower 50 are both connected to the naphtha pipeline.

[0033] A feed inlet is provided on the side of the heavy separation column 10 to allow raw materials to enter the column for separation of heavy components. The raw materials are the bottom liquid from the C7 removal column, and the components in the bottom liquid are C7 components and components below C7. A top outlet is provided at the top of the heavy separation column 10, and the top outlet is connected to the top reflux pump 30. A bottom outlet is provided at the bottom of the heavy separation column 10, and the bottom outlet is connected to the naphtha pipeline to collect the naphtha product from the bottom liquid. A reflux port is also provided on the side of the heavy separation column 10 to allow the top components to be refluxed. Preferably, the feed inlet is located on the left side of the heavy separation column 10, the reflux port is located on the right side of the column 10, and the reflux port is located between the feed inlet and the top outlet.

[0034] During operation, the top component of the heavy separator 10 is split into two streams. One stream flows back into the heavy separator 10 via a side stream for secondary mass transfer separation, improving the recovery of the top component. The other stream enters the de-heavy separator 50 to purify and separate the methylcyclohexane from the top component. The methylcyclohexane obtained after separation and purification in the de-heavy separator 50 is split into two streams from the top of the de-heavy separator 50. One stream flows back into the de-heavy separator 50 via a side stream for secondary mass transfer separation, while the other stream enters the product tank 80 to obtain the methylcyclohexane product with a purity ≥99.5% and improved yield, thus increasing the utilization rate of raw materials. Furthermore, the bottom liquid of the heavy separator 10 flows into the naphtha pipeline, where the methylcyclohexane content is significantly reduced. This invention uses a de-heavy separation tower 50 to purify and separate methylcyclohexane from the top component of a heavy separation tower. While ensuring the purity of methylcyclohexane, it increases the yield of methylcyclohexane, thereby reducing the content of methylcyclohexane in the bottom liquid of the heavy separation tower. This significantly improves the utilization rate of raw materials, avoids direct economic losses, and increases profits.

[0035] In one possible embodiment of this utility model, a heavy separation tower reflux control valve 101 is installed between the other end of the heavy separation tower top reflux pump 30 and the tower side of the heavy separation tower 10; a heavy separation tower feed control valve 103 is installed between the other end of the heavy separation tower top reflux pump 30 and the tower side of the de-heavy separation tower 50. The heavy separation tower reflux control valve 101 controls the opening and closing of the reflux pipelines installed at the top of the heavy separation tower and the tower side of the heavy separation tower 10, and simultaneously controls the flow rate of the reflux material (the component at the top of the heavy separation tower) by adjusting the opening degree of the heavy separation tower reflux control valve 101; the heavy separation tower feed control valve 103 controls the opening and closing of the pipeline between the top of the heavy separation tower and the heavy separation tower 50, and simultaneously controls the flow rate of the material (the component at the top of the heavy separation tower) entering the heavy separation tower 50 by adjusting the opening degree of the heavy separation tower feed control valve 103. Preferably, a small portion of the top component of the heavy separation column is refluxed back into the heavy separation column 10 for secondary mass transfer separation; the majority of the top component of the heavy separation column enters the de-heavy separation column 50 for separation and purification.

[0036] In one possible embodiment of this utility model, a de-weighting tower reflux control valve 105 is installed between the de-weighting tower reflux pump 70 and the tower side of the de-weighting tower 50; a de-weighting tower product control valve 106 is installed between the de-weighting tower reflux pump 70 and the product tank 80. The de-weighting tower reflux control valve 105 controls the opening and closing of the reflux pipeline between the top of the de-weighting tower and the tower side, and simultaneously controls the flow rate of the material (top component of the de-weighting tower) refluxed into the de-weighting tower 50 by the valve opening degree of the de-weighting tower reflux control valve 105; the de-weighting tower product control valve 106 controls the opening and closing of the pipeline between the top of the de-weighting tower and the product tank 80, and simultaneously controls the flow rate of the material (top component of the de-weighting tower) entering the product tank 80 by the valve opening degree of the de-weighting tower product control valve 106; preferably, most of the top component of the de-weighting tower enters the product tank 80, and a small portion refluxes back into the de-weighting tower 50. It should be noted that the top component of the de-weighting tower is the methylcyclohexane product.

[0037] See Figure 2 The heavy component removal tower 50 employs a negative pressure fractionation process, with a top pressure of -0.06 MPa, achieving high-purity separation of the target components. To improve the separation and purification efficiency of the heavy component removal tower 50, a reboiler 90 is connected to the lower side of the tower. The heat source for the reboiler 90 is low-pressure steam at 0.5 MPa, which not only improves the separation efficiency but also reduces energy consumption due to the use of low-pressure steam. The connection method and operation of the reboiler 90 are existing technologies in the field and will not be described in detail here.

[0038] Preferably, the heavy separation tower 50 has a top outlet at the top, a feed inlet on the left side, and a reflux inlet on the right side, located between the top outlet and the feed inlet. The bottom outlet is also provided at the bottom. The feed inlet is connected to the heavy separation tower top reflux pump 30 to transport the heavy separation tower top components to the heavy separation tower 50 for separation and purification. The top outlet is connected to one end of the heavy separation tower reflux pump 70, and the reflux inlet is connected to the other end, enabling the reflux of the heavy separation tower top components. The bottom outlet is connected to a naphtha pipeline to collect the naphtha product from the bottom of the heavy separation tower.

[0039] In one possible embodiment of this utility model, the methylcyclohexane separation and recovery device further includes a naphtha transfer pump 40; the bottom of the heavy separation tower 10 and the bottom of the de-heavy separation tower 50 are both connected to the naphtha pipeline via the naphtha transfer pump 40. The naphtha transfer pump 40 provides power for the outflow of the heavy separation tower bottom liquid generated at the bottom of the heavy separation tower 10 and the de-heavy separation tower bottom liquid generated at the bottom of the de-heavy separation tower 50, facilitating their entry into the naphtha pipeline.

[0040] In one possible embodiment of this utility model, a heavy separation tower bottom control valve 102 is installed between the bottom of the heavy separation tower 10 and the naphtha transfer pump 40; the discharge of the heavy separation tower bottom liquid is controlled by the heavy separation tower bottom control valve 102; and a de-heavy separation tower bottom control valve 107 is installed between the bottom of the de-heavy separation tower 50 and the naphtha transfer pump 40. The discharge of the heavy separation tower bottom liquid is controlled by the heavy separation tower bottom control valve 102, and the discharge of the de-heavy separation tower bottom liquid is controlled by the de-heavy separation tower bottom control valve 107.

[0041] In one possible embodiment of this utility model, a heavy separation column reflux tank 20 is provided between the top of the heavy separation column 10 and the heavy separation column top reflux pump 30. By providing the heavy separation column reflux tank 20, the components from the top of the heavy separation column first enter the heavy separation column reflux tank 20, and then are refluxed and fed by the heavy separation column top reflux pump 30, which plays a buffering role and improves the stability of operation.

[0042] In one possible embodiment of this utility model, a deweighting tower reflux tank 60 is provided between the top of the deweighting tower 50 and the deweighting tower reflux pump 70. By providing the deweighting tower reflux tank 60, the components at the top of the deweighting tower first enter the deweighting tower reflux tank 60, and then are refluxed and discharged by the deweighting tower reflux pump 70, which plays a buffering role and improves the stability of operation.

[0043] In one possible embodiment of this utility model, the other end of the heavy fractionation tower top reflux pump 30 is also connected to the product tank 80. This design ensures system operational stability; in the event of an emergency in the de-heavy fractionation tower 50, most of the components at the top of the heavy fractionation tower are not purified and separated, but directly enter the product tank 80, ensuring stable and continuous production. Preferably, a heavy fractionation tower product control valve 104 is installed between the other end of the heavy fractionation tower top reflux pump 30 and the product tank 80. Under normal circumstances, the heavy fractionation tower product control valve 104 is closed, and the de-heavy fractionation tower feed control valve 103 is open, allowing the components at the top of the heavy fractionation tower to enter the de-heavy fractionation tower 50 for separation and purification. In an emergency, the heavy fractionation tower product control valve 104 is opened, and the de-heavy fractionation tower feed control valve 103 is closed, allowing the components at the top of the heavy fractionation tower to enter the product tank 80.

[0044] Taking the actual production of methylcyclohexane in oil-rich Shenmu as an example, the technical advantages of the methylcyclohexane separation and recovery device provided by this utility model are verified. Specifically, in May, a heavy separation tower and a solvent recovery tower (existing methods) were used for the production and recovery of methylcyclohexane. The average value of methylcyclohexane in the bottom liquid of the heavy separation tower was 15.90%, and the average yield of methylcyclohexane was 83.26%. In June, the methylcyclohexane separation and recovery device provided by this utility model was modified, that is, a heavy separation tower and a de-heavy separation tower were used for the production and recovery of methylcyclohexane. After 14 days of production operation in July, the average yield of methylcyclohexane increased from 83.62% to 93%, and the purity of methylcyclohexane was ≥99.5%; the average value of methylcyclohexane in the bottom liquid of the heavy separation tower was 6.38%.

[0045] A comparison before and after the modification shows that, with the same raw material input, approximately 9.38% more methylcyclohexane can be recovered, thus increasing methylcyclohexane production. Simultaneously, the methylcyclohexane content in the bottom liquid of the heavy separation tower decreases, resulting in a relative reduction in naphtha production. Calculations show that the increase in methylcyclohexane production is not significantly different from the decrease. Based on the price difference between naphtha and methylcyclohexane, and after deducting the steam consumption cost of the heavy separation tower, the annual profit could exceed one million yuan. The methylcyclohexane separation and recovery device provided by this invention not only effectively improves the yield of methylcyclohexane and significantly enhances the conversion efficiency and resource utilization of raw materials, but also increases economic benefits, achieving the goals of energy saving, cost reduction, and efficiency improvement.

[0046] It should be noted that in this utility model, the connecting pipelines between the various devices are DN40 carbon steel pipelines; blind flanges are also added to the connecting pipeline between the heavy separation tower top reflux pump 30 and the heavy separation tower 50, and to the rear end of the heavy separation tower feed control valve 103; and blind flanges are also added to the connecting pipeline between the outlet of the heavy separation tower reflux pump 70 and the product tank 80, and to the rear end of the heavy separation tower product control valve 106. These blind flanges prevent media leakage and ensure system safety; furthermore, the connecting pipelines between the devices are purged and purged with nitrogen before commissioning, thereby improving the safety of the unit's operation.

[0047] It should be noted that all the equipment used in this utility model (heavy separation tower, heavy separation tower, valves, and pumps, etc.) are commercially available and conventional in the field, and all of them can meet the technical requirements for pressure, temperature, etc. during operation. Furthermore, the installation and connection methods of all connecting pipelines, valves, and pumps are conventional and known technologies in the field, and will not be described in detail here.

[0048] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A methylcyclohexane separation and recovery device, characterized in that, Includes a heavy separation tower (10), a heavy separation tower top reflux pump (30), a heavy separation tower (50), a heavy separation tower reflux pump (70), a product tank (80), and a naphtha pipeline; The top of the heavy separation tower (10) is connected to one end of the heavy separation tower top reflux pump (30); the other end of the heavy separation tower top reflux pump (30) is connected to the tower side of the heavy separation tower (10) and the tower side of the de-heavy tower (50) respectively; the top of the de-heavy tower (50) is connected to the tower side of the de-heavy tower (50) and the product tank (80) respectively after passing through the de-heavy tower reflux pump (70).

2. The methylcyclohexane separation and recovery device according to claim 1, characterized in that, A reflux control valve (101) for the heavy separator is provided between the other end of the reflux pump (30) at the top of the heavy separator and the side of the heavy separator (10); a feed control valve (103) for the heavy separator is provided between the other end of the reflux pump (30) at the top of the heavy separator and the side of the heavy separator (50).

3. The methylcyclohexane separation and recovery device according to claim 1, characterized in that, A de-weighting tower reflux control valve (105) is provided between the de-weighting tower reflux pump (70) and the tower side of the de-weighting tower (50); a de-weighting tower product control valve (106) is provided between the de-weighting tower reflux pump (70) and the product tank (80).

4. The methylcyclohexane separation and recovery device according to claim 1, characterized in that, A reflux tank (20) is provided between the top of the redistribution tower (10) and the redistribution tower top reflux pump (30).

5. The methylcyclohexane separation and recovery device according to claim 1, characterized in that, A deweight removal tower reflux tank (60) is provided between the top of the deweight removal tower (50) and the deweight removal tower reflux pump (70).

6. The methylcyclohexane separation and recovery device according to claim 1, characterized in that, The other end of the top reflux pump (30) of the redistribution tower is also connected to the product tank (80).

7. The methylcyclohexane separation and recovery device according to claim 6, characterized in that, A product control valve (104) for the heavy separation tower is installed between the other end of the top reflux pump (30) and the product tank (80).

8. The methylcyclohexane separation and recovery device according to claim 1, characterized in that, The methylcyclohexane separation and recovery unit also includes a naphtha pipeline and a naphtha transfer pump (40); the bottom of the heavy separation tower (10) and the bottom of the de-heavy tower (50) are both connected to the naphtha pipeline via the naphtha transfer pump (40).

9. The methylcyclohexane separation and recovery device according to claim 8, characterized in that, A bottom control valve (102) for the heavy separation tower (10) is provided between the bottom of the tower and the naphtha transfer pump (40).

10. The methylcyclohexane separation and recovery apparatus according to claim 8, characterized in that, A deweight removal tower bottom control valve (107) is provided between the bottom of the deweight removal tower (50) and the naphtha transfer pump (40).

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