Oil-water separation device based on water-containing crude benzene in benzene hydrogenation process

Abstract

The invention discloses an oil-water separation device based on water-containing crude benzene in a benzene hydrogenation process, relates to the technical field of oil-water separation, and is based on the basic principle of oil-water separation and the density difference of a liquid mixture, and the key is that when a crude benzene product is mixed with production wastewater, the pressure intensity change on an air bag part and the buoyancy change on an air floating bag are changed; the pressure change of the air bag part is mainly used for preliminarily judging the layering state of a liquid mixture, related parameters are provided for the discharge action of production wastewater, and the layering state of two media is further fed back in cooperation with the balance relation between the buoyancy of the air floating bag and the gravity of the balancing weight, so that the layering state of the liquid mixture is determined on the basis. The key point is that the discharge process of the production wastewater is directly controlled according to the judgment result, and the discharge process is used for reducing the residual volume of the production wastewater or the recovery rate of a crude benzene product after the discharge action is completed.

Description

Technical Field

[0001] The invention relates to the technical field of oil-water separation, and in particular to an oil-water separation device based on water-containing crude benzene in a benzene hydrogenation process. Background Art

[0002] Oil-water separation uses the density difference between two media (liquids) to achieve the separation effect. It can be applied to wastewater treatment, industrial production and other fields. Taking the benzene hydrogenation process as an example, because the relative density of crude benzene is less than the density of water, stratification occurs. In the production process, it is necessary to remove the precipitated production wastewater and retain the crude benzene on the upper layer.

[0003] However, since it is impossible to truly detect whether all the wastewater has been discharged, the only option is to increase the discharge volume (wastewater), causing part of the crude benzene to be discharged into the wastewater tank, reducing the crude benzene recovery rate, or cutting into the system when the wastewater is not completely discharged, causing disorder in process control parameters and even causing shutdown, which has a significant impact on the long-term safe and stable operation of the entire production line. This application proposes a solution. Summary of the invention

[0004] The object of the present invention is to provide an oil-water separation device based on water-containing crude benzene in the benzene hydrogenation process. Regarding the oil-water separation process in the benzene hydrogenation process, since it is difficult to control the discharge amount of wastewater, it may cause the wastewater to not be completely discharged or cause the crude benzene to enter the wastewater tank, which directly affects the process control parameters and thus affects the safety and stability of the production line operation.

[0005] The object of the present invention can be achieved by the following technical scheme: an oil-water separation device for water-containing crude benzene in a benzene hydrogenation process, comprising a kettle body, a liquid injection port is provided at the upper end of the outer wall of the kettle body, and a through port is provided at the lower end of the kettle body, a partition cover is installed in the inner position of the kettle body located below the liquid injection port, and an intermediate empty chamber is provided inside the kettle body through the partition cover;

[0006] An active execution structure is installed at the center point of the top end of the outer wall of the kettle body, and a vertically arranged transmission rod is installed at the output end of the active execution structure. The transmission rod penetrates downward into the interior of the kettle body, and an air float and a counterweight are arranged in the interior position of the partition cover corresponding to the transmission rod along the direction from top to bottom, and an air pressure sensor is arranged in the vertical direction of the partition cover.

[0007] It is further configured as follows: the separation cover is composed of a connecting pipe and two fixed cone caps, the fixed cone caps are installed in the inner wall position of the kettle body along the vertical direction, and the connecting pipe is installed in the middle position of the two fixed cone caps.

[0008] It is further configured as follows: the intermediate empty chamber is located in the middle position between the inner wall of the kettle body and the outer wall of the connecting pipe, the air pressure sensor is located in the intermediate empty chamber, and the air pressure sensor transmission position extends in the vertical direction to the outer wall position of the fixed cone cap, and an airbag component is installed on the air pressure sensor transmission position.

[0009] It is further configured as follows: an upper cone cap is slidably mounted on the upper side of the transmission rod corresponding to the partition cover, a gap is provided between the upper cone cap and the fixed cone cap located at the upper side, and the cross section of the upper cone cap is conical.

[0010] It is further configured as follows: the air flotation bag and the counterweight block are located in the inner position of the connecting tube, the air flotation bag and the transmission rod are slidably connected, and the counterweight block and the transmission rod are fixedly connected.

[0011] The oil-water separation device is provided with the following process during operation:

[0012] Process 1: A fixed amount of liquid mixture is injected into the kettle through the liquid injection port, and the kettle does not perform wastewater discharge, and the initial positions of the airbag and the air float are directly calibrated, and the stratification state of the liquid mixture is preliminarily judged through the active execution structure and the air pressure sensor;

[0013] Process 2: After obtaining the stratified state in the kettle body based on process 1, the wastewater discharge action is started, and the air flotation bag and the counterweight block are recalculated through the active execution structure to re-judge the stratified state of the liquid mixture in the kettle body during the discharge action;

[0014] Process three: Based on process one and process two, the discharge volume of produced wastewater per unit time in the wastewater discharge action in process two is first set, and the discharge volume of produced wastewater per unit time in the wastewater discharge action is reset according to the result of re-judgment based on the stratification state of the liquid mixture.

[0015] The present invention has the following beneficial effects:

[0016] 1. According to the basic principle of oil-water separation, a calculation method of pressure and buoyancy is proposed based on the density difference of liquid mixture. First of all, for the pressure calculation process, the key lies in the airbags arranged in the vertical direction, which are specifically used to detect the pressure changes at the upper and lower positions, so that the stratification state of the liquid mixture can be directly fed back according to the relevant values ​​in the air pressure sensor. However, it is not used as the key reference data in the production wastewater action, but mainly provides relevant parameters for the discharge process of production wastewater;

[0017] 2. Based on the above contents, the present invention specifically takes the balance process of the air flotation bag and the counterweight block as the key content. Because the density difference of the liquid mixture will directly break the balance state of the air flotation bag and the counterweight block, the stratification state of the two media can be further fed back. Based on this, the key is to directly control the discharge process of the production wastewater through the above judgment results, specifically to control the discharge volume per unit time in the subsequent discharge action, which is used to reduce the residual amount of production wastewater or the recovery rate of crude benzene product after the discharge action is completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a schematic structural diagram of an oil-water separation device for water-containing crude benzene in a benzene hydrogenation process proposed by the present invention;

[0020] Figure 2 It is a cross-sectional view of the kettle body in the oil-water separation device of the water-containing crude benzene in the benzene hydrogenation process proposed by the present invention;

[0021] Figure 3 The oil-water separation device of the crude benzene containing water in the benzene hydrogenation process proposed by the present invention Figure 2 A front view of

[0022] Figure 4 This is a disassembled diagram of a separation cover in an oil-water separation device for crude benzene containing water in a benzene hydrogenation process proposed by the present invention;

[0023] Figure 5 It is a cross-sectional view of a separation cover in an oil-water separation device for water-containing crude benzene in a benzene hydrogenation process proposed by the present invention;

[0024] Figure 6 The oil-water separation device of the crude benzene containing water in the benzene hydrogenation process proposed by the present invention Figure 5 Front view of .

[0025] In the figure: 1, kettle body; 101, liquid filling port; 102, middle empty chamber; 2, active execution structure; 3, transmission rod; 4, upper cone cap; 5, partition cover; 6, air pressure sensor; 7, airbag component; 8, air float; 9, counterweight block. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1: For the oil-water separation process in the benzene hydrogenation process, since it is difficult to control the discharge volume of wastewater, the wastewater may not be completely discharged or crude benzene may enter the wastewater tank, which directly affects the process control parameters and thus affects the operation safety and stability of the production line. The following technical solutions are proposed:

[0028] Reference Figures 1 to 6 The oil-water separation device based on water-containing crude benzene in the benzene hydrogenation process in this embodiment includes a kettle 1, a liquid injection port 101 is provided at the upper end of the outer wall of the kettle 1, and a through port is provided at the lower end of the kettle 1, a partition cover 5 is installed in the inner position of the kettle 1 below the liquid injection port 101, and an intermediate empty chamber 102 is provided inside the kettle 1 through the partition cover 5;

[0029] An active execution structure 2 is installed at the center point of the top of the outer wall of the kettle body 1, and a vertically arranged transmission rod 3 is installed at the output end of the active execution structure 2. The transmission rod 3 penetrates downward into the inner position of the kettle body 1, and an air floating bag 8 and a counterweight block 9 are arranged in the inner position of the separation cover 5 corresponding to the transmission rod 3 from top to bottom, and the separation cover 5 is provided with an air pressure sensor 6 in the vertical direction;

[0030] The partition cover 5 is composed of a connecting pipe and two fixed cone caps. The fixed cone caps are installed on the inner wall of the kettle body 1 along the vertical direction. The connecting pipe is installed in the middle position of the two fixed cone caps. The intermediate empty chamber 102 is located in the middle position between the inner wall of the kettle body 1 and the outer wall of the connecting pipe. The air pressure sensor 6 is located in the intermediate empty chamber 102, and the transmission position of the air pressure sensor 6 extends to the outer wall position of the fixed cone caps along the vertical direction. An airbag component 7 is installed on the transmission position of the air pressure sensor 6.

[0031] Working principle: The essence of oil-water separation is to use the density difference of liquid medium. For the benzene hydrogenation process, the density of water is about 1.0g / cm³, while the density of crude benzene is 0.87-0.91g / cm³. Therefore, it can be understood that in the crude benzene production process, the crude benzene mixture floats on the water surface. For this, the conventional oil-water separation process is to naturally precipitate the mixture of crude benzene and production wastewater to form layers, and discharge the production wastewater at the lower layer;

[0032] As shown above, it is difficult to actually control the discharge volume during the process of discharging production wastewater, causing part of the crude benzene to be discharged into the wastewater tank, reducing the crude benzene recovery rate, or cutting into the system before the wastewater is completely discharged, causing disorder in process control parameters and even causing shutdown, which has a great impact on the long-term safe and stable operation of the entire production line. Figure 3 After the crude benzene and the production wastewater are separated, two air pressure sensors 6 are first used to detect the pressure change inside the airbag 7, which is explained below:

[0033] S1: In the initial state, because the relative positions of the two airbag components 7 are constant, and the same volume of gas is filled inside to expand the airbag components 7 to a constant state, and combined with the hydraulic pressure change principle, after a certain amount of liquid mixture is injected through the liquid injection port 101, the liquid level inside the kettle body 1 can be known, and combined with the position height of the two airbag components 7, the pressure borne by the two airbag components 7 can be directly obtained, so the air pressure sensors 6 in the two corresponding positions can obtain corresponding values;

[0034] S2: Based on S1, additional explanation is given. If the density of the entire liquid mixture is close to 1.0g / cm³, the displayed values ​​of the two air pressure sensors 6 can be directly calculated based on the height difference of the two airbags 7. However, the injected liquid mixture contains two key substances, water and crude benzene, so its density cannot be directly measured. When the liquid mixture is layered and the production wastewater in the lower layer is discharged, the displayed values ​​of the two air pressure sensors 6 can also be directly obtained through the relevant dimensions of the kettle body 1 and the discharge volume per unit time. In this process, it is important to explain that:

[0035] Because the pressure formula is only related to the density and liquid level height, the displayed value of the air pressure sensor 6 has no relationship with the spread volume in the kettle body 1. However, it needs to be further explained that: after the liquid mixture is stratified, assuming that the bottom layer of the crude benzene after stratification is in contact with the airbag component 7 at the top layer, the density value used in the pressure formula for this position should be the density of the crude benzene product, that is, 0.87-0.91g / cm³, but the density value used in the initial state is the density of water. It can be understood that the pressure difference between the two states is large due to the density difference, so that the density difference when the liquid mixture is discharged can be preferentially detected in this way.

[0036] Embodiment 2: Based on Embodiment 2, further explanation is given for the partition cover:

[0037] An upper cone cap 4 is slidably installed on the upper side of the transmission rod 3 corresponding to the partition cover 5. A gap is provided between the upper cone cap 4 and the fixed cone cap located at the upper side, and the cross-section of the upper cone cap 4 is conical. The air float 8 and the counterweight 9 are located in the internal position of the connecting tube. The air float 8 and the transmission rod 3 are slidably connected, and the counterweight 9 and the transmission rod 3 are fixedly connected.

[0038] Solution description: This embodiment mainly focuses on the principle of buoyancy. Taking the buoyancy calculation formula as an example, F 浮 =ρ 液 Xgf 排 , where V 排 Indicates the volume of liquid displaced by the object, from which it can be understood that: buoyancy is also directly related to the liquid level and the liquid density, as shown in Example 1, where the liquid level / liquid level volume can be directly obtained, the key lies in the change of liquid density;

[0039] When the liquid mixture is completely injected into the kettle body 1 and the layers are separated, it is necessary to ensure that the integral separation cover 5 is arranged at the lower side of the kettle body 1, so as to ensure that the counterweight block 9 and the transmission rod 3 are just located inside the water layer, so that the corresponding buoyancy can be directly calculated through the volume change of the air float 8 and the liquid medium, and the counterweight block 9 of the corresponding weight can be selected according to the calculated buoyancy value;

[0040] In the initial state, the weight of the counterweight block 9 is balanced with the buoyancy of the air float 8, so that the entire transmission rod 3 is in a relatively constant state. Even in the process of discharging industrial wastewater, the transmission rod 3 will reciprocate up and down with a small amplitude, and the moving speed and moving range of the transmission rod 3 can be directly calculated;

[0041] However, with the continuous discharge of industrial wastewater, on the one hand, the liquid level in the kettle body 1 continues to drop, and the degree of drop can also be directly calculated by the unit discharge volume. On the other hand, when the liquid level of the bottom layer of the crude benzene product contacts the air float 8, the density of the water body contacted by the air float 8 is reduced, resulting in a greater reduction in buoyancy, which directly breaks the balance relationship between the air float 8 and the counterweight 9. In this way, the discharge status of the crude benzene product and industrial wastewater can be directly judged.

[0042] Embodiment 3: Supplementary explanation is given in combination with Embodiment 1 and Embodiment 2. The essence of the active execution structure 2 is used to directly determine the movement amplitude of the transmission rod 3. Therefore, the active execution structure 2 can be composed of a structure such as a displacement sensor and a controller. In the specific operation process, the following control method is generated:

[0043] Method 1: A constant amount of liquid mixture is injected into the kettle body 1, and the liquid level height inside the kettle body 1 is directly obtained according to the inner diameter of the kettle body 1 and the size of the partition cover 5, and the stratification state of the liquid mixture is sensed by referring to two groups of air pressure sensors 6 arranged in the vertical direction;

[0044] Specifically, when the displayed values ​​of the two air pressure sensors 6 tend to be stable, the water density at the two positions is reversely calculated in combination with the liquid level height in the kettle body 1 and the setting height of the airbag 7. Specifically, when the displayed values ​​of the two air pressure sensors 6 tend to be stable, it can be directly indicated that the stratification of the liquid mixture is completed;

[0045] Method 2: Further utilizing the moving value of the transmission rod 3, because when the industrial wastewater in the lower layer is not discharged, the buoyancy of the air float 8 is balanced with the gravity of the counterweight 9, and because the partition cover 5 is located at the lower layer of the kettle body, the buoyancy of the air float 8 should be calculated based on the density of water. However, when the industrial wastewater in the lower layer begins to be discharged, the liquid level in the kettle body 1 continues to drop;

[0046] Specifically, the overall capacity of the crude benzene product has not changed, but the amount of production wastewater in the lower layer has decreased, so that the displayed values ​​of the two air pressure sensors 6 are reduced first. However, when the airbags 7 at the upper and lower sides are completely contained in the crude benzene product or the water body, the displayed value in the air pressure sensor 6 is only related to the liquid level. However, with the continuous discharge of industrial wastewater, the airbag 7 at the top layer will preferentially detect the stratification problem of the crude benzene product and the production wastewater. Specifically, when the crude benzene product contacts the airbag 7 at the top layer, the displayed value in the air pressure sensor 6 at this position changes first, thereby preliminarily detecting the stratification state of the liquid mixture.

[0047] Method 3: If Figure 3 As shown, the position of the air flotation bag 8 is lower than the uppermost air bag member 7. After the stratification state of the liquid mixture is detected first in the second method, an "early warning" can also be performed through the balance conversion process of buoyancy and weight.

[0048] Specifically, when the stratified state in the second mode appears, the residual liquid level inside the kettle body 1 is obtained again by the discharge amount of the production wastewater per unit time, and the production wastewater is slowly discharged by reducing the discharge amount of the production wastewater. In this process, because the liquid level inside the kettle body 1 continues to decrease, the buoyancy of the air float 8 is reduced, so the gravity of the counterweight 9 causes the transmission rod 3 to move downward. The speed and movement stroke of the transmission rod 3 are directly obtained by the active execution structure 2, and the second mode is combined to illustrate again;

[0049] When the lower layer of the crude benzene product contacts the air float 8, the density of the contacted medium decreases, resulting in a significant decrease in the buoyancy it bears, and the transmission rod 3 tends to move downward more. When the displayed value of the displacement sensor in the active execution structure 2 appears in this state, the remaining volume of the liquid mixture in the kettle body 1 can be directly calculated, and the remaining capacity of the production wastewater in the kettle body 1 can be directly obtained by referring to the initial position of the transmission rod 3 and the total stroke length. Based on this method, the drainage volume per unit time is further controlled. Based on the calculated residual capacity, after discharging an equal amount of liquid, the kettle body 1 only retains the crude benzene product, without production wastewater or with a very small amount of production wastewater.

[0050] In summary: based on the basic principle of oil-water separation and the density difference of the liquid mixture, the key is reflected in the pressure change on the airbag and the buoyancy change of the air float when the crude benzene product is mixed with the production wastewater. The pressure change on the airbag is mainly used to preliminarily judge the stratification state of the liquid mixture, and provide relevant parameters for the discharge of the production wastewater. In combination with the balance between the buoyancy of the air float and the gravity of the counterweight, the stratification state of the two media is further fed back. Based on this, the key is to directly control the discharge process of the production wastewater through the above-mentioned judgment results, and to reduce the residual amount of production wastewater or the recovery rate of the crude benzene product after the discharge action is completed.

[0051] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An oil-water separation device for water-containing crude benzene in a benzene hydrogenation process, comprising a kettle (1), characterized in that: The upper end of the outer wall of the kettle body (1) is provided with a liquid injection port (101), and the lower end of the kettle body (1) is provided with a through opening; a partition cover (5) is installed in the inner position of the kettle body (1) below the liquid injection port (101), and an intermediate empty chamber (102) is arranged inside the kettle body (1) through the partition cover (5); An active execution structure (2) is installed at the center point of the top end of the outer wall of the kettle body (1), and a vertically arranged transmission rod (3) is installed at the output end of the active execution structure (2). The transmission rod (3) penetrates downward into the interior of the kettle body (1), and an air flotation bag (8) and a counterweight (9) are arranged in a direction from top to bottom in the interior of the partition cover (5) corresponding to the transmission rod (3), and an air pressure sensor (6) is arranged in the vertical direction of the partition cover (5).

2. The oil-water separation device based on water-containing crude benzene in the benzene hydrogenation process according to claim 1 is characterized in that: The partition cover (5) is composed of a connecting pipe and two fixed cone caps. The fixed cone caps are installed in the inner wall of the kettle body (1) in a vertical direction, and the connecting pipe is installed in the middle of the two fixed cone caps.

3. The oil-water separation device based on water-containing crude benzene in the benzene hydrogenation process according to claim 2 is characterized in that: The intermediate hollow chamber (102) is located at a position intermediate between the inner wall of the kettle body (1) and the outer wall of the connecting pipe, the air pressure sensor (6) is located in the intermediate hollow chamber (102), and the transmission position of the air pressure sensor (6) extends in a vertical direction to a position on the outer wall of the fixed cone cap, and an airbag component (7) is installed at the transmission position of the air pressure sensor (6).

4. The oil-water separation device based on water-containing crude benzene in the benzene hydrogenation process according to claim 1, characterized in that: An upper cone cap (4) is slidably mounted on the transmission rod (3) at an upper position corresponding to the partition cover (5), a gap is provided between the upper cone cap (4) and a fixed cone cap located at the upper position, and the cross section of the upper cone cap (4) is conical.

5. The oil-water separation device based on water-containing crude benzene in the benzene hydrogenation process according to claim 2, characterized in that: The air flotation bag (8) and the counterweight block (9) are located inside the connecting tube; the air flotation bag (8) and the transmission rod (3) are slidably connected, and the counterweight block (9) and the transmission rod (3) are fixedly connected.

6. The oil-water separation device based on water-containing crude benzene in the benzene hydrogenation process according to any one of claims 1 to 5, characterized in that: The oil-water separation device is provided with the following process during operation: Process 1: a fixed amount of liquid mixture is injected into the kettle (1) through the liquid injection port (101), and the kettle (1) does not perform the waste water discharge action, and directly calibrates the initial positions of the airbag component (7) and the air float (8), and makes a preliminary judgment on the stratification state of the liquid mixture through the active execution structure (2) and the air pressure sensor (6); Process 2: After obtaining the stratified state in the kettle (1) based on process 1, the wastewater discharge action is started, and the air flotation bag (8) and the counterweight block (9) are recalculated through the active execution structure (2) to re-judge the stratified state of the liquid mixture in the kettle (1) during the discharge action; Process three: Based on process one and process two, the discharge volume of produced wastewater per unit time in the wastewater discharge action in process two is first set, and the discharge volume of produced wastewater per unit time in the wastewater discharge action is reset according to the result of re-judgment based on the stratification state of the liquid mixture.

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