Tank structure for liquid-liquid coalescence separation

Abstract

The utility model discloses a tank structure for liquid-liquid coalescence separation, which is used for liquid-liquid separation operation in petrochemical industry and comprises a tank body, an anti-disturbance liquid distributor, a first-stage plate-type coalescer, a second-stage fibration silk screen coalescer and a third-stage fibration silk screen coalescer, a feeding pipe is arranged on the left side of the interior of the tank body, and a feeding port of the feeding pipe is formed in the upper surface of the tank body; the first-stage plate-type coalescer is arranged at a position close to the feeding pipe; an anti-disturbance liquid distributor is arranged on the left side of the first-stage plate-type coalescer; the second-stage fibration silk screen coalescer and the third-stage fibration silk screen coalescer are arranged on the right side of the first-stage plate-type coalescer; the second-stage fibration silk screen coalescer and the third-stage fibration silk screen coalescer are arranged side by side; the discharging pipe is of an L-shaped structure, a discharging port of the discharging pipe is formed in the upper surface of the middle of the tank body, and an inlet of the discharging pipe is formed in the right side of the interior of the tank body. The liquid-liquid two-phase coalescer can be used for coalescing and separating the liquid phase and the liquid phase generated by reaction.

Description

Technical Field

[0001] The utility model belongs to the technical field of liquid-liquid separation tanks, especially sedimentation tanks, dehydration tanks or water washing tanks used in petrochemical industry. Background Art

[0002] The liquid-phase sulfuric acid alkylation method is a process for producing high-octane gasoline components. The production principle of the liquid-phase sulfuric acid method is to use sulfuric acid as a catalyst to carry out an alkylation reaction between olefins and isobutane at low temperature to produce high-octane alkylated oil. The technological process includes: raw material pretreatment, purifying and drying olefins and isobutane to remove impurities and moisture; alkylation reaction, feeding the pretreated olefins and isobutane into an alkylation reactor to carry out an alkylation reaction under the action of a sulfuric acid catalyst; product separation, separating the reaction products to obtain alkylated oil and waste sulfuric acid; waste sulfuric acid treatment, treating the waste sulfuric acid to recover sulfuric acid therein and carry out recycling.

[0003] The sulfuric acid method is mainly applied in the oil refining industry to produce high-octane gasoline components. In addition, this method can also be used to produce other chemicals, such as isobutene, MTBE, etc.

[0004] In the sulfuric acid method, the acid sedimentation tank plays an important role. One of the main functions of the acid sedimentation tank is to separate sulfuric acid (catalyst) from hydrocarbon substances. After the alkylation reaction, the reaction product is a mixture of alkylated oil and sulfuric acid. After entering the acid sedimentation tank, due to the density difference, sulfuric acid will settle to the bottom, while hydrocarbon substances will float on the top, thus achieving preliminary separation. The sulfuric acid settled at the bottom of the tank can be recovered and recycled. This not only reduces the production cost but also reduces environmental pollution. After certain treatment and purification, sulfuric acid can be transported back to the alkylation reactor to continue to play a catalytic role.

[0005] As Figure 1 shown, for the existing acid sedimentation tank used in the similar DuPont sulfuric acid method, the feeding is carried out through the inlet at the middle part of the tank, and the discharging is carried out through the outlet 102 at the top. The feeding is of H-shaped structure, and the bottom of the inlet and outlet pipes is provided with holes. There is no coalescer element in the tank. This structure will lead to incomplete acid-hydrocarbon separation, unstable operation, the acid-hydrocarbon separation not meeting the process requirements, a large amount of sulfuric acid in the hydrocarbon, resulting in high operation costs, and seriously corroding downstream equipment and endangering production. Summary of the Invention

[0006] The purpose of the utility model is to provide a tank structure for liquid-liquid coalescence separation, which can be applied to the alkylation of the similar DuPont sulfuric acid method, save the usage amount of acid, and improve the acid-hydrocarbon separation efficiency.

[0007] To achieve the above object, the present utility model provides a tank structure for liquid-liquid coalescence separation, which is used for liquid-liquid separation operation in petrochemical industry, and includes: a tank body, an anti-disturbance liquid distributor, a primary plate coalescer, a secondary fibrous mesh coalescer and a tertiary fibrous mesh coalescer; a feed pipe is arranged on the left side inside the tank body, and the feed inlet of the feed pipe is arranged on the upper surface of the tank body; the primary plate coalescer is arranged at a position close to the feed pipe; an anti-disturbance liquid distributor is arranged on the left side of the primary plate coalescer; the secondary fibrous mesh coalescer and the tertiary fibrous mesh coalescer are arranged on the right side of the primary plate coalescer; the secondary fibrous mesh coalescer and the tertiary fibrous mesh coalescer are arranged side by side; the discharge pipe is of an L-shaped structure, its discharge port is arranged on the upper surface in the middle of the tank body, and the inlet is arranged on the right side inside the tank body.

[0008] In an embodiment of the present utility model, a feed distributor is further arranged at the outlet of the feed pipe inside the tank body; the feed distributor is of a tubular structure, and a plurality of holes are arranged on the pipe.

[0009] In an embodiment of the present utility model, the side surface of the feed distributor is evenly divided into four surfaces, and equal-spacing and uniform holes are arranged on three of the surfaces, and the other surface has no holes and faces the anti-disturbance liquid distributor.

[0010] In an embodiment of the present utility model, the primary plate coalescer is arranged on the entire cross-section of the tank body.

[0011] In an embodiment of the present utility model, a partition is arranged below the secondary fibrous mesh coalescer and the tertiary fibrous mesh coalescer.

[0012] In an embodiment of the present utility model, a gap is left between the partition and the bottom of the tank body.

[0013] In an embodiment of the present utility model, the height of the partition is 0 mm - 1000 mm.

[0014] In an embodiment of the present utility model, the secondary fibrous mesh coalescer, the tertiary fibrous mesh coalescer and the partition are arranged on the entire cross-section of the tank body.

[0015] Compared with the prior art, according to a tank structure for liquid-liquid coalescence separation of the present utility model, the flow setting from left to right in the tank body may make the acid and hydrocarbon in the tank have a more definite direction during the flow process, making it easier for the acid and hydrocarbon to be stratified during the flow, avoiding the difficulty of separation caused by uneven local mixing; reducing the unnecessary carrying away of acid in the subsequent treatment, saving the usage amount of acid, avoiding excessive use of acid, and achieving the purpose of saving and environmental protection. Description of the Drawings

[0016] Figure 1 is the acid settling tank used in the DuPont sulfuric acid process in the prior art;

[0017] Figure 2 is a schematic structural diagram of a tank structure for liquid-liquid coalescence separation according to an embodiment of the present invention;

[0018] Figure 3 is Figure 2 the A-A cross-sectional view in

[0019] Figure 4 is Figure 2 the B-B cross-sectional view in

[0020] Figure 5 is Figure 2 the D-D cross-sectional view in

[0021] Main reference numeral description:

[0022] 1 - Tank body, 2 - Feed pipe, 3 - Anti-disturbance liquid distributor, 4 - Primary plate coalescer, 5 - Secondary fibrous screen coalescer, 6 - Tertiary fibrous screen coalescer, 7 - Discharge pipe, 8 - Partition board, 9 - Feed port, 10 - Discharge port, 11 - Inlet. Detailed Embodiments

[0023] The following combines the drawings to describe in detail the specific embodiments of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0024] Unless otherwise clearly stated, in the whole specification and claims, the term "comprising" or its variations such as "including" or "having" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0025] As Figures 2 to 5 shown, a tank structure for liquid-liquid coalescence separation according to a preferred embodiment of the present invention is mainly used in liquid-liquid separation operations in petrochemical industry (for example, in the reaction process of DuPont sulfuric acid process), and includes: tank body 1, feed pipe 2, anti-disturbance liquid distributor 3, primary plate coalescer 4, secondary fibrous screen coalescer 5, tertiary fibrous screen coalescer 6 and discharge pipe 7.

[0026] The feed pipe 2 is arranged on the left side inside the tank body 1, extending from the upper part to the bottom, and the feed port 9 of the feed pipe 2 is arranged on the upper surface of the tank body.

[0027] Inside the tank body 1, a feed distributor 201 is also provided at the outlet of the feed pipe 2. The feed distributor 201 is a tubular structure, and multiple holes are provided on the pipe, enabling the feed to be evenly distributed within the tank body 1 rather than accumulating at the outlet of the feed pipe 2. This setting can redistribute the feed. During the entire reaction process, the reaction materials are evenly distributed, with a longer residence time inside the tank body 1 and a more sufficient reaction. Among them, the side surface of the feed distributor 201 is evenly divided into four surfaces, and three of these surfaces are provided with equally spaced and uniform holes, while the other surface has no holes and faces the anti-disturbance liquid distributor 3.

[0028] A primary plate coalescer 4 is provided at a position close to the feed pipe 2. As Figure 4 shown, the primary plate coalescer 4 is arranged across the entire cross-section of the tank body 1, and thus can cover the flow area of the materials to the greatest extent, ensuring that all the materials entering the tank body 1 will pass through the primary plate coalescer 4 for sedimentation separation, initially improving the acid-hydrocarbon separation effect.

[0029] The primary plate coalescer 4 utilizes the difference in sedimentation velocities of substances with different densities in the liquid under the action of gravity, causing the heavier liquid droplets or solid particles to settle to the bottom of the coalescer, which can promote the preliminary sedimentation separation of the liquid-liquid two phases in the reaction materials. In the primary plate coalescer 4, the light and heavy fine particles in the liquid phase quickly settle on the upper and lower surfaces of the primary plate coalescer 4, namely the light phase and the heavy phase. The liquid droplets collide and coalesce with each other, increasing their particle size. When the particles increase to a certain extent, due to the action of gravity, they can be more efficiently sedimented and separated, accelerating the separation between the two immiscible liquids.

[0030] For example, when the tank structure for liquid-liquid coalescence separation of the present invention is applied to a production process similar to the DuPont sulfuric acid method, it can cause the tiny acid-phase particles (catalyst sulfuric acid) in the production process to collide and coalesce with each other, increasing the particle size of the acid mist particles, and sedimenting and separating from the two phases due to the action of gravity, thereby greatly improving the acid removal efficiency and reducing the adverse effects of the acid phase on subsequent equipment and the environment.

[0031] An anti-disturbance liquid distributor 3 is provided on the left side of the primary plate coalescer 4, and this anti-disturbance liquid distributor 3 is arranged between the primary plate coalescer 4 and the feed pipe 2. The anti-disturbance liquid distributor 3 can evenly distribute the feed and minimize the disturbance, making the feed more evenly distributed over the cross-sectional area of the tank body 1, and can also avoid the spraying and turbulence phenomena of the feed, preventing the uneven distribution of the liquid phase in the tank caused by capacity expansion or operation fluctuations.

[0032] On the right side of the primary plate coalescer 4, there are a secondary fibrous screen coalescer 5 and a tertiary fibrous screen coalescer 6. The secondary fibrous screen coalescer 5 and the tertiary fibrous screen coalescer 6 are generally arranged side by side to achieve the second and third aggregations of even tinier liquid particles. The secondary fibrous screen coalescer 5 and the tertiary fibrous screen coalescer 6 are 0 - 1000 mm away from the bottom of the tank body 1.

[0033] The primary plate coalescer 4 makes use of the small gap distance between plates (compared with the upper and lower tank bottoms of the empty tank, the sedimentation distance of liquid droplets is shortened, and small liquid droplets coalesce into large liquid droplets on the plate surface; while the secondary fibrous screen coalescer 5 and the tertiary fibrous screen coalescer 6 utilize the direct interception or collision of small-diameter wire meshes to coalesce small liquid droplets into large liquid droplets.

[0034] The secondary fibrous screen coalescer 5 and the tertiary fibrous screen coalescer 6 are high-efficiency coalescers woven from two different surface free energy materials: such as metals and non-metals (plastics, polyesters, fiberglass, etc.). Through the fibrous screen coalescer woven from metal and non-metal, the advantages of the two materials are fully utilized. The metal part can usually provide mechanical strength and stability and can withstand a certain amount of pressure and impact force. The non-metal part may have special surface properties, such as low surface free energy, which helps to improve the coalescence efficiency. The woven structure can increase the surface area and provide more attachment and coalescence opportunities for tiny particles in the fluid, thereby improving the performance of the coalescer. In the petrochemical industry, for fluids containing corrosive media, the non-metal part can provide good corrosion resistance, while the metal part ensures the mechanical strength of the equipment.

[0035] Below the secondary fibrous screen coalescer 5 and the tertiary fibrous screen coalescer 6, there can be a baffle plate 8, which can block impurities and viscous substances (such as sulfate esters) from entering the secondary fibrous screen coalescer 5 and the tertiary fibrous screen coalescer 6 at the bottom. The height of the baffle plate 8 is 0 - 1000 mm. There is a certain gap between the baffle plate 8 and the bottom of the tank body 1 to facilitate the passage of impurities and viscous substances (such as sulfate esters).

[0036] Figure 5 The figure shows a schematic structural diagram of the secondary fibrous screen coalescer 5, the tertiary fibrous screen coalescer 6, and the baffle plate 8 arranged on the entire cross-section of the tank body 1. Figure 5 It is a left-right symmetric structure. The left side shows the baffle plate for fixing the fibrous screen coalescer, and the right side is the fibrous screen coalescer.

[0037] In order to utilize the position of the original tank outlet pipe, in the present utility model, the discharge pipe 7 is changed to an L-shaped structure. On the right side of the entire tank body 1, the discharge is on the right side of the tank body 1, and the entire process extends from the left to the right of the tank body 1, with a longer residence time, making it easier for the liquid-liquid phase products to settle and separate during flow, thereby achieving a better separation effect; the uniform flow distribution helps the liquid-liquid two-phase products to have a more stable distribution state throughout the tank body, avoiding separation difficulties caused by uneven local mixing. This uniformity can make the separation process more efficient and improve the separation purity.

[0038] Through the above structural settings, the liquid-liquid two phases can be better separated, and the proportion of the heavy phase in the outlet liquid phase will be further reduced.

[0039] For example, when a tank structure for liquid-liquid coalescence separation of the present utility model is applied to a production process similar to the DuPont sulfuric acid process, the separation effect of acid and hydrocarbon in the product is better, and the loss of acid during the mixing with hydrocarbon can be reduced. When the separation of acid and hydrocarbon is not thorough, it may cause the acid to be carried away unnecessarily in subsequent processing, while good separation can keep more acid in the required links, thus saving the usage amount of acid. Saving the usage amount of acid itself reduces the potential pollution risk that the acid may cause to the environment. If the usage amount of acid is reduced, then the acid discharged into the environment during the production process will also be correspondingly reduced, reducing the potential harm to environmental elements such as soil and water bodies. In addition, better acid-hydrocarbon separation can reduce the energy required for separation.

[0040] The foregoing description of the specific exemplary embodiments of the present utility model is for the purposes of illustration and exemplification. These descriptions are not intended to limit the present utility model to the precise forms disclosed, and obviously, many changes and variations can be made in light of the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present utility model and its practical applications, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present utility model, as well as various different selections and changes. The scope of the present utility model is intended to be defined by the claims and their equivalents.

Claims

1. A tank structure for liquid-liquid coalescence separation, characterized in that, The liquid-liquid separation operation for petrochemical industry includes: a tank body, an anti-disturbance liquid distributor, a primary plate coalescer, a secondary fibrous mesh coalescer and a tertiary fibrous mesh coalescer; a feed pipe is arranged on the left side inside the tank body, and the feed inlet of the feed pipe is arranged on the upper surface of the tank body; the primary plate coalescer is arranged at a position close to the feed pipe; an anti-disturbance liquid distributor is arranged on the left side of the primary plate coalescer; the secondary fibrous mesh coalescer and the tertiary fibrous mesh coalescer are arranged on the right side of the primary plate coalescer; the secondary fibrous mesh coalescer and the tertiary fibrous mesh coalescer are arranged side by side; the discharge pipe is of an L-shaped structure, its discharge outlet is arranged on the upper surface in the middle of the tank body, and the inlet is arranged on the right side inside the tank body.

2. The tank structure for liquid-liquid coalescence separation according to claim 1, characterized in that, Inside the tank body, a feed distributor is further arranged at the outlet of the feed pipe; the feed distributor is of a tubular structure, and a plurality of holes are arranged on the pipe.

3. The tank structure for liquid-liquid coalescence separation according to claim 2, wherein, The side surface of the feed distributor is evenly divided into four surfaces, and equal-spacing and uniform holes are arranged on three of the surfaces, and the other surface has no holes and faces the anti-disturbance liquid distributor.

4. The tank structure for liquid-liquid coalescence separation according to claim 1, characterized in that, The primary plate coalescer is arranged on the entire cross-section of the tank body.

5. The tank structure for liquid-liquid coalescence separation according to claim 1, characterized in that, A partition plate is arranged below the secondary fibrous mesh coalescer and the tertiary fibrous mesh coalescer.

6. The tank structure for liquid-liquid coalescence separation according to claim 5, wherein A gap is left between the partition plate and the bottom of the tank body.

7. The tank structure for liquid-liquid coalescence separation according to claim 5, wherein The height of the partition plate is 0 mm - 1000 mm.

8. The tank structure for liquid-liquid coalescence separation according to claim 5, characterized in that, The secondary fibrous mesh coalescer, the tertiary fibrous mesh coalescer and the partition plate are arranged on the entire cross-section of the tank body.

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