A liquid phase adsorption separation system and its application

Abstract

The present invention relates to a liquid-phase adsorption separation system and its application. The system includes an adsorption tower body and three or more adsorbent beds arranged in the adsorption tower body, with a mixing-distribution internal component provided between two adjacent adsorbent beds; the mixing-distribution internal component includes an upper support grid, an intermediate mixing-distributor, and a lower support grid; the intermediate mixing-distributor includes an inlet and outlet pipe, an inlet and outlet conical distribution chamber, a conical mixing chamber, and a conical discharge chamber; the inlet and outlet pipes pass through the upper support grid and the adsorption tower body and are connected to the outside world, the inlet and outlet conical distribution chamber is connected to the inlet and outlet pipes, the conical mixing chamber is provided below the inlet and outlet conical distribution chamber and is connected to the inlet and outlet conical distribution chamber, and the conical discharge chamber is provided below the conical mixing chamber and is connected to the conical mixing chamber. Compared with the prior art, the present invention has the advantages of low production cost, high product purity, and high yield.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorption separation, in particular to a liquid phase adsorption separation system and application thereof. Background Art

[0002] The three isomers of dichlorobenzene—o-dichlorobenzene, m-dichlorobenzene, and p-dichlorobenzene—are all important organic chemical raw materials. o-dichlorobenzene is primarily used as a raw material for organic synthesis, a solvent for dye production, a cleaning agent, a solvent for waxes and tars, and a raw material for the synthesis of pesticides. p-dichlorobenzene is primarily used in the synthesis of pesticides, as a preservative, and as a solvent. m-dichlorobenzene is widely used as an intermediate in the synthesis of dyes, pharmaceuticals, and pesticides, and is a major raw material for the fungicides imazalil, propiconazole, and ethiconazole. Dichlorobenzenes are primarily synthesized through the chlorination of benzene or chlorobenzene. However, chlorination of benzene or chlorobenzene primarily produces o-dichlorobenzene and p-dichlorobenzene, with m-dichlorobenzene being a very small source. m-dichlorobenzene is primarily produced through the isomerization of o-dichlorobenzene or p-dichlorobenzene. The isomerization of o-dichlorobenzene or p-dichlorobenzene produces a mixture of o-, m-, and p-dichlorobenzene isomers. Traditionally, the above-mentioned isomerization reaction uses solid aluminum trichloride as a catalyst, and the isomerization reaction is carried out in a batch reactor using a batch production method. The reaction product is then washed with water and decoked to obtain the isomerized product. Among the three dichlorobenzene isomers, o-dichlorobenzene has a boiling point of 179°C, p-dichlorobenzene has a boiling point of 174°C, a melting point of 53°C, and m-dichlorobenzene has a boiling point between 171-173°C, and a melting point of -24°C. Therefore, traditionally, o-dichlorobenzene is obtained by distillation separation, p-dichlorobenzene is obtained by crystallization separation, and the remaining m-dichlorobenzene is further obtained by distillation. Using the above-mentioned traditional m-dichlorobenzene production method, not only is the isomerization reaction batch production, generating a large amount of wastewater, but the distillation and crystallization separation also require a large amount of energy consumption. At the same time, the production process is long, the three wastes are discharged in large quantities, the equipment investment is large, and the production cost is high, which is uneconomical.

[0003] In recent years, there has been a large amount of research on the production of meta-dichlorobenzene both domestically and internationally. Patent CN112452103A describes a method for producing high-purity meta-dichlorobenzene by vapor-phase adsorption separation. This method uses MFI molecular sieves and X-type molecular sieves as adsorbents to adsorb p-dichlorobenzene and o-dichlorobenzene, leaving m-dichlorobenzene as the unadsorbed portion. The resulting m-dichlorobenzene has a purity of 95.5%. This method involves vapor-phase adsorption, requiring a large amount of heat of vaporization, cooling water, and other energy consumption, resulting in a relatively low m-dichlorobenzene purity. Patent CN1315217A discloses a method for separating mixed dichlorobenzenes using liquid-phase selective adsorption of hydrophobic silicalite. This method uses an MFI-type hydrophobic silicalite molecular sieve adsorbent to adsorb o-dichlorobenzene and / or p-dichlorobenzene, leaving m-dichlorobenzene as the unadsorbed portion. However, this method does not specify the purity of the m-dichlorobenzene achieved. Neither of these patents specifies the specific structure of the adsorption tower equipment or the adsorption efficiency. EP0334025A1 discloses a method for separating isomers of halogenated benzene derivatives. In an example, o-dichlorobenzene is first subjected to a liquid-phase isomerization reaction in a fixed-bed reactor over a ZSM-5 molecular sieve catalyst to produce three dichlorobenzene isomers. These isomers are then separated in a simulated moving bed adsorption tower to obtain the meta-dichlorobenzene product, achieving a purity of 99.5% and a recovery rate of 95%. Patents such as JP04330025, JP11158093, JP11180911, and JP11335308 disclose methods for separating dichlorobenzene isomers using a simulated moving bed adsorption tower to obtain high-purity meta-dichlorobenzene. These methods employ an ion-modified Y-type molecular sieve or other molecular sieve as an adsorbent to adsorb o-dichlorobenzene and p-dichlorobenzene. The unadsorbed meta-dichlorobenzene is then distilled to obtain the high-purity product. Patent US4996380A discloses another method for separating dichlorobenzene isomers by adsorption. It uses an ion-modified X-type molecular sieve as an adsorbent to adsorb meta-dichlorobenzene, leaving ortho-dichlorobenzene and para-dichlorobenzene unadsorbed. Meta-dichlorobenzene is then removed using a desorbent to yield a high-purity meta-dichlorobenzene product. None of these patents clearly define the adsorption tower structure or the fluid distribution within it.

[0004] Patents US6156197A, WO2006 / 055222A1, CN1131394A, CN101056684A, CN201592090U, CN103084084B, etc. disclose a fluid mixing and distribution device or component that can be used in equipment loaded with multiple sections of fillers or adsorbents. In the components disclosed in the above patents, when the fluids are mixed and redistributed, baffles are set at the mixing point or the outlet of the mixed fluid to prevent the fluid from directly flowing out and impacting the lower layer of fillers or adsorbents, thereby forming a fluid distribution blind spot under the baffle; in addition, in order to obtain a more uniform fluid distribution, the above patents divide the entire adsorption tower into several different areas, but when the fluids are mixed and redistributed in each area, different flow rates are not designed according to the distance of distribution, so the distribution in each area is still uneven. Summary of the Invention

[0005] The purpose of the present invention is to provide a liquid phase adsorption separation system and its application, which has more reasonable fluid mixing and distribution and higher adsorption efficiency.

[0006] The object of the present invention can be achieved by the following technical solution: A liquid phase adsorption separation system comprises an adsorption tower body and three or more adsorbent beds arranged in the adsorption tower body, wherein a mixing-distribution internal component is provided between two adjacent adsorbent beds;

[0007] The mixing-distributing internal components include an upper supporting grid, a middle mixing-distributor and a lower supporting grid;

[0008] The intermediate mixing-distributor includes an inlet and outlet pipe, an inlet and outlet conical distribution chamber, a conical mixing chamber and a conical discharge chamber, and the inlet and outlet conical distribution chamber, the conical mixing chamber and the conical discharge chamber are all arranged between the upper support grid and the lower support grid;

[0009] The inlet and outlet pipes pass through the upper support grid and the adsorption tower body and are connected to the outside world. The inlet and outlet conical distribution chamber is connected to the inlet and outlet pipes. The conical mixing chamber is arranged below the inlet and outlet conical distribution chamber and is connected to the inlet and outlet conical distribution chamber. The conical discharge chamber is arranged below the conical mixing chamber and is connected to the conical mixing chamber.

[0010] Preferably, the inlet and outlet conical distribution chamber comprises a half pipe and two perforated plates;

[0011] The two perforated plates form a conical structure, and the half pipe is arranged on the top of the conical structure and is connected with the inlet and outlet pipes.

[0012] Further preferably, the cone angle of the cone structure is 30°-60°.

[0013] Further preferably, each of the perforated plates has 3-6 rows of holes, a hole diameter of 2-25 mm, a hole spacing of 4-15 times the hole diameter, and a flow rate through the holes of 3.0-10.0 m / s.

[0014] Preferably, the conical mixing chamber comprises two conical mixing chamber partitions and two inclined conical mixing chamber baffles;

[0015] One end of the conical mixing chamber partition is fixed, and the other end is connected to the conical mixing chamber baffle. A mixing channel is formed between the conical mixing chamber baffle and the inlet and outlet conical distribution chamber, and a conical mixing chamber outlet is formed between the bottoms of the two conical mixing chamber baffles.

[0016] Further preferably, one end of the conical mixing chamber partition is connected to the adsorption tower body or the middle support tube, and the other end is connected to the conical mixing chamber baffle.

[0017] Further preferably, the conical mixing chamber baffle is parallel to the perforated plate of the inlet and outlet conical distribution chamber.

[0018] Further preferably, the flow velocity of the mixing channel is 1.5-3.5 m / s.

[0019] Further preferably, the outlet flow rate of the conical mixing chamber is 0.5-1.5 m / s.

[0020] Preferably, the conical discharge chamber includes two inclined conical discharge chamber baffles, and a discharge channel is formed between the conical discharge chamber baffles and the conical mixing chamber.

[0021] Further preferably, the conical discharge chamber baffle is parallel to the conical mixing chamber baffle.

[0022] Further preferably, the outlet flow velocity at the cone tail of the discharge channel is 0.1-0.5 m / s.

[0023] Further preferably, the two conical discharge chamber baffles have 3-6 rows of holes, and the hole diameter gradually increases from the cone tip to the cone tail. The hole diameter near the cone tip is 2-5 mm, the hole diameter near the cone tail is 10-15 mm, and the hole diameter in the middle is 5-10 mm.

[0024] More preferably, the flow rate of the opening holes at the tail of the cone is 0.1-0.5 m / s, the flow rate of the opening holes at the tip of the cone is 0.5-1.0 m / s, and the flow rate of the opening holes in the middle is between the former two.

[0025] Preferably, the mixing-distributing internal component is divided into 2-20 sub-internal components of equal area, each sub-internal component is isolated by a partition plate, and each sub-internal component is provided with an intermediate mixing-distributor.

[0026] Preferably, the adsorbent bed has 3 to 20 layers, and the adsorbent bed is filled with adsorbent.

[0027] Further preferably, the adsorbent is solid particles.

[0028] An application of the above-mentioned liquid-phase adsorption separation system, wherein the liquid-phase adsorption separation system is used to produce high-purity meta-dichlorobenzene, comprises the following steps:

[0029] Fresh feed enters the inlet and outlet conical distribution chamber from the first layer of inlet and outlet pipes, and then flows into the mixing channel from the perforated plate of the inlet and outlet conical distribution chamber. The circulating material in the adsorption tower body passes through different adsorbent beds and mixing-distribution internal components from top to bottom, and is then blocked by the baffle of the conical mixing chamber and can only enter the mixing channel of the conical mixing chamber, where it is completely mixed with the fresh feed. The evenly mixed fluid flows out from the outlet of the conical mixing chamber and enters the conical discharge chamber. The fluid flows out through the baffle opening of the conical discharge chamber and the discharge channel;

[0030] The fresh feed comprises o-dichlorobenzene, p-dichlorobenzene and m-dichlorobenzene;

[0031] The recycled material comprises o-dichlorobenzene, p-dichlorobenzene and m-dichlorobenzene;

[0032] The fresh feed and the recycled material are adsorbed by at least N layers (N is not less than 3) of adsorbent beds, and the residual liquid after adsorption is extracted from the inlet and outlet pipes of the N+1 layer;

[0033] Preferably, a circulation pipeline and a circulation pump are provided outside the adsorption tower body, and the circulation pipeline and the circulation pump circulate the fluid flowing out from the bottom head of the adsorption tower body to the upper part as circulating material.

[0034] In the present invention, the circulating material is a mixture of o-dichlorobenzene, p-dichlorobenzene and m-dichlorobenzene circulated from a circulating pump outside the tower.

[0035] Preferably, the adsorbent filled in the adsorbent bed is an adsorbent for adsorbing o-dichlorobenzene and p-dichlorobenzene or an adsorbent for adsorbing m-dichlorobenzene.

[0036] In the present invention, after fresh feed and recycled materials are treated by the system of the present invention, o-dichlorobenzene and p-dichlorobenzene or m-dichlorobenzene are adsorbed by the adsorbent, and the residual liquid is m-dichlorobenzene and the desorbent remaining in the adsorbent or o-dichlorobenzene and p-dichlorobenzene and the desorbent remaining in the adsorbent. The desorbent is separated and reused, and a high-purity m-dichlorobenzene product or a mixture of o-dichlorobenzene and p-dichlorobenzene is obtained at the same time.

[0037] More preferably, the adsorbent loaded in the adsorbent bed is an adsorbent that adsorbs o-dichlorobenzene and p-dichlorobenzene.

[0038] Further preferably, the adsorbent is an X-type molecular sieve, a Y-type molecular sieve, a ZSM series molecular sieve, or a SAPO series molecular sieve modified with a Group IA or Group IIA metal.

[0039] Preferably, the adsorption temperature is 150-250° C., and the adsorption pressure is 0.5-1.5 MPa.

[0040] Preferably, the application of the liquid phase adsorption separation system further comprises the following steps:

[0041] 50 to 250 seconds after the start of fresh feeding, the fresh feeding is stopped, and the desorbent enters the inlet and outlet conical distribution chamber from the first layer of inlet and outlet pipes, and then desorbs the o-dichlorobenzene, p-dichlorobenzene or m-dichlorobenzene adsorbed in the adsorbent along the same channel as the fresh feed;

[0042] The desorption liquid after desorption is drawn out from the inlet and outlet pipes of the N+1th layer (N is not less than 3).

[0043] In the present invention, the desorption liquid comprises o-dichlorobenzene, p-dichlorobenzene and a desorbent, or m-dichlorobenzene and a desorbent. The desorbent is separated and reused, and a mixture of o-dichlorobenzene and p-dichlorobenzene or a high-purity m-dichlorobenzene product is obtained. The desorbent remains in the adsorbent.

[0044] The mixture of o-dichlorobenzene and p-dichlorobenzene separated from the raffinate or desorption liquid can be recycled to the system of the present invention or to the dichlorobenzene isomerization unit to increase the production of m-dichlorobenzene.

[0045] Further preferably, the desorbent is chlorobenzene, dichlorotoluene, xylene or a mixture thereof.

[0046] More preferably, the desorption temperature is 150-250° C., and the desorption pressure is 0.5-1.5 MPa.

[0047] The invention provides an adsorption tower device for preparing meta-dichlorobenzene, which mainly solves the problems of uneven mixing of fluids in the adsorption tower and blind spots in distribution in the previous meta-dichlorobenzene preparation technology.

[0048] An application of the above-mentioned liquid-phase adsorption separation system, wherein the liquid-phase adsorption separation system is used to produce high-purity p-xylene, comprises the following steps:

[0049] Fresh feed enters the inlet and outlet conical distribution chamber from the first layer of inlet and outlet pipes, and then flows into the mixing channel from the perforated plate of the inlet and outlet conical distribution chamber. The circulating material in the adsorption tower body passes through different adsorbent beds and mixing-distribution internal components from top to bottom, and is then blocked by the baffle of the conical mixing chamber and can only enter the mixing channel of the conical mixing chamber, where it is completely mixed with the fresh feed. The evenly mixed fluid flows out from the outlet of the conical mixing chamber and enters the conical discharge chamber. The fluid flows out through the baffle opening of the conical discharge chamber and the discharge channel;

[0050] The fresh feed comprises o-xylene, p-xylene and m-xylene;

[0051] The recycle material comprises o-xylene, p-xylene and m-xylene.

[0052] Preferably, the adsorbent filled in the adsorbent bed is an adsorbent that adsorbs p-xylene.

[0053] Further preferably, the adsorbent is an X-type molecular sieve, a Y-type molecular sieve, a ZSM series molecular sieve, or a SAPO series molecular sieve modified with a Group IA or Group IIA metal.

[0054] After being treated by the system of the present invention, p-xylene is adsorbed by the adsorbent, and the residual liquid is o-xylene, m-xylene and the desorbent remaining in the adsorbent. The desorbent is separated and reused, and a mixture of o-xylene and m-dichlorobenzene is obtained at the same time.

[0055] Preferably, the liquid phase adsorption separation system is used to produce high-purity p-xylene, further comprising the following steps:

[0056] 50 to 250 seconds after the start of fresh feeding, the fresh feeding is stopped, and the desorbent enters the inlet and outlet conical distribution chamber from the first layer of inlet and outlet pipes, and then desorbs the p-xylene adsorbed in the adsorbent along the same channel as the fresh feed;

[0057] The desorption liquid after desorption is drawn out from the inlet and outlet pipes of the N+1th layer (N is not less than 3).

[0058] In the present invention, the desorption liquid includes p-xylene and a desorbent, the desorbent is separated and reused, and a high-purity p-xylene product is obtained at the same time. At this time, the desorbent remains in the adsorbent.

[0059] The mixture of o-xylene and m-xylene separated from the raffinate or desorption liquid can be recycled to the system of the present invention or to the xylene isomerization unit to further increase the production of p-xylene.

[0060] Further preferably, the desorbent is toluene, diethylbenzene or a mixture thereof.

[0061] More preferably, the desorption temperature is 150-250° C., and the desorption pressure is 0.5-1.5 MPa.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] 1. The fluid in the adsorption tower of the present invention is evenly mixed, and the tapered discharge structure avoids the formation of fluid distribution blind spots in the tower. This can solve the problems of uneven fluid mixing and low adsorption efficiency in traditional adsorption tower equipment, making the fluid mixing and distribution more reasonable and the adsorption efficiency higher.

[0064] 2. The present invention comprises multiple adsorbent beds with mixing-distribution internals installed between the beds. These internals are designed with different orifice flow rates for different distribution distances, avoiding blind spots in fluid distribution, and offering advantages such as uniform distribution and high adsorption efficiency.

[0065] 3. The present invention is a liquid phase adsorption process, which avoids the equipment investment and energy consumption of gasification and condensation, and has the advantages of small investment and low energy consumption;

[0066] 4. The present invention has high adsorption efficiency, the purity of the obtained meta-dichlorobenzene is greater than 99.5%, and the recovery rate of meta-dichlorobenzene can reach more than 95%;

[0067] 5. The present invention is applicable to the production of high-purity meta-dichlorobenzene or high-purity para-xylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a partial longitudinal cross-sectional schematic diagram of the liquid phase adsorption separation system of the present invention;

[0069] Figure 2 This is a schematic diagram of the structure of the mixing-distribution internal component of the present invention;

[0070] Figure 3 This is a schematic structural diagram of the inlet and outlet conical distribution chamber in the mixing-distribution internal component of the present invention;

[0071] Figure 4 Schematic diagram of the structure of the conical mixing chamber in the mixing-distributing internal component of the present invention;

[0072] Figure 5 Schematic diagram of the structure of the conical discharge chamber in the mixing-distributing internal component of the present invention;

[0073] Figure 6 This is a cross-sectional view of the adsorption tower body of the present invention. The longitudinal section along the AA direction can be obtained. Figure 1 ;

[0074] In the figure: 1-adsorption tower body, 2-adsorbent bed, 3-mixing-distribution internal component, 31-upper support grid, 32-intermediate mixing-distributor, 321-inlet and outlet pipes, 322-inlet and outlet conical distribution chamber, 3221-half pipe, 3222-perforated plate, 3223-perforated plate opening, 323-conical mixing chamber, 3231-conical mixing chamber partition, 3232-conical mixing chamber baffle, 3233-mixing channel, 3234-conical mixing chamber outlet, 324-conical discharge chamber, 3241-conical discharge chamber baffle, 3242-discharge channel, 3243-baffle opening, 33-lower support grid, 4-partition plate, 5-intermediate support pipe. DETAILED DESCRIPTION

[0075] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0076] Example 1

[0077] A liquid-phase adsorption separation system comprises an adsorption tower body 1, an adsorbent bed 2 and a mixing-distribution internal component 3.

[0078] Among them, the mixing-distribution internal component 3 includes an upper supporting grid 31, an intermediate mixing-distributor 32 and a lower supporting grid 33, and the intermediate mixing-distributor 32 includes an inlet and outlet pipe 321, an inlet and outlet conical distribution chamber 322, a conical mixing chamber 323 and a conical discharge chamber 324.

[0079] Specifically, more than three adsorbent beds 2 are provided in the adsorption tower body 1, the mixing-distribution internal component 3 is arranged between two adjacent adsorbent beds 2, the upper support grid 31 is arranged at the bottom of the upper adsorbent bed 2, and the lower support grid 33 is arranged at the top of the lower adsorbent bed 2. The inlet and outlet conical distribution chamber 322, the conical mixing chamber 323 and the conical discharge chamber 324 of the intermediate mixing-distributor 32 are arranged between the upper support grid 31 and the lower support grid 33, the inlet and outlet pipes 321 pass through the upper support grid 31 and the adsorption tower body 1 to communicate with the outside world, the inlet and outlet conical distribution chamber 322 is communicated with the inlet and outlet pipes 321, the conical mixing chamber 323 is arranged below the inlet and outlet conical distribution chamber 322 and communicated with the inlet and outlet conical distribution chamber 322, and the conical discharge chamber 324 is arranged below the conical mixing chamber 323 and communicated with the conical mixing chamber 323.

[0080] The liquid-phase adsorption separation system of this embodiment can be used to separate and treat a mixed dichlorobenzene containing o-dichlorobenzene, p-dichlorobenzene, and m-dichlorobenzene to produce high-purity m-dichlorobenzene.

[0081] Specifically, the following steps may be included:

[0082] During adsorption, fresh mixed dichlorobenzene enters the conical inlet and outlet distribution chamber 322 from the inlet and outlet pipes 321, and then enters the conical mixing chamber 323. The circulating material in the adsorption tower body 1 passes through different adsorbent beds 2 and mixing-distribution internals 3 from top to bottom, and also enters the conical mixing chamber 323. The fresh mixed dichlorobenzene and the circulating material are evenly mixed in the conical mixing chamber 323 and then flow out through the conical discharge chamber 324. After passing through the next layer of adsorbent bed 2 and mixing-distribution internals 3 from top to bottom, and after passing through N layers (N is not less than 3) of adsorbent beds 2 and mixing-distribution internals 3, the residual liquid is extracted from the inlet and outlet pipes 321 of the N+1 layer. The rest is circulated from the lower part of the adsorption tower body 1 to the upper part of the adsorption tower by external circulation equipment and re-enters the adsorption tower body 1 as circulating material.

[0083] During desorption, the fresh mixed dichlorobenzene is replaced by the desorbent. The desorbent follows the same path as the fresh mixed dichlorobenzene, and the desorption liquid is drawn out from the inlet and outlet pipes 321 of the N+1 layer.

[0084] Example 2

[0085] An adsorption tower device for preparing m-dichlorobenzene, such as Figure 1 As shown, it includes three or more adsorbent beds 2, and a mixing-distribution internal component 3 is installed between every two adsorbent beds 2; Figure 2 As shown, the internal component consists of an upper supporting grid 31, an intermediate mixing-distributor 32, and a lower supporting grid 33; the intermediate mixing-distributor 32 consists of an inlet and outlet pipe 321, an inlet and outlet conical distribution chamber 322, a conical mixing chamber 323, and a conical discharge chamber 324.

[0086] The adsorbent bed 2 preferably has 3 to 20 layers, and the adsorbent bed 2 is filled with an adsorbent for adsorbing o-dichlorobenzene and p-dichlorobenzene or an adsorbent for adsorbing m-dichlorobenzene.

[0087] The adsorbent is preferably an X-type molecular sieve, a Y-type molecular sieve, a ZSM series molecular sieve, or a SAPO series molecular sieve modified with a Group IA or Group IIA metal.

[0088] like Figure 3 As shown, the inlet and outlet conical distribution chamber 322 of the intermediate mixing-distributor 32 is composed of a half pipe 3221 and two perforated plates 3222; the two perforated plates 3222 preferably each have 3-6 rows of holes (perforated plate holes 3223), the hole diameter is preferably 2-25 mm, the hole spacing is preferably 4-15 times the hole diameter, the hole flow rate is preferably 3.0-10.0 m / s, and the hole flow rate is proportional to the distance from the hole position to the tower wall or the partition plate 4.

[0089] Specifically, the top of the inlet and outlet conical distribution chamber 322 of the intermediate mixing-distributor 32 is a semi-tube structure (half-tube 3221), which can ensure that there is no static area at the top of the inlet and outlet conical distribution chamber 322; the orifice plates on both sides (perforated plates 3222) are perforated, and the orifice flow rate is proportional to the distance from the orifice position to the tower wall or the partition plate 4. The farther the orifice position is from the tower wall or the partition plate 4, the greater the orifice flow rate, and vice versa; this design can ensure that the fluid takes the same time to reach the tower wall or the partition plate 4, thereby ensuring uniform fluid distribution.

[0090] like Figure 4 As shown, the conical mixing chamber 323 of the intermediate mixing-distributor 32 is composed of two partitions (conical mixing chamber partitions 3231) and two inwardly inclined baffles (conical mixing chamber baffles 3232); the two baffles and the inlet and outlet conical distribution chamber 322 form a mixing channel 3233, and the flow rate of the mixing channel is preferably 1.5-3.5 m / s; the flow rate at the conical mixing chamber outlet 3234 is preferably 0.5-1.5 m / s.

[0091] Specifically, the conical mixing chamber 323 of the intermediate mixer-distributor 32 has two partitions (conical mixing chamber partitions 3231) on either side, separating the fluid within the adsorption tower. This partition allows the fluid to flow only through the mixing channel 3233, which is formed by two inwardly inclined baffles (conical mixing chamber baffles 3232) and the inlet and outlet conical distribution chamber 322. The feed is ejected through the openings in the conical distribution chamber's baffles, mixing with the fluid flowing up and down within the adsorption tower in the mixing channels 3233 on either side of the mixing chamber. It then flows out through the bottom outlet of the conical mixing chamber 323 (conical mixing chamber outlet 3234). The flow rate at the outlet is lower than that at the mixing channel 3233, ensuring no backmixing or reflux. This design ensures that the feed mixes thoroughly with the fluid within the adsorption tower.

[0092] like Figure 5 As shown, the conical discharge chamber 324 of the intermediate mixing-distributor 32 is composed of two outwardly inclined baffles (conical discharge chamber baffle 3241); the two baffles preferably have 3-6 rows of holes (baffle openings 3243), and the hole diameter gradually increases from the tip of the cone to the tail of the cone. The hole diameter near the tip of the cone is preferably 2-5 mm, the hole diameter near the tail of the cone is preferably 10-15 mm, and the hole diameter in the middle is preferably 5-10 mm; the hole flow rate of the hole at the tail of the cone is preferably 0.1-0.5 m / s, the hole flow rate of the hole at the tip of the cone is preferably 0.5-1.0 m / s, and the hole flow rate of the hole in the middle is between the first two.

[0093] Specifically, the conical discharge chamber 324 of the intermediate mixer-distributor 32 is formed by two outward-angled baffles (conical discharge chamber baffles 3241) and the conical mixing chamber 323, forming discharge channels 3242 on either side. Holes (baffle openings 3243) are formed on the two baffles, and the apertures gradually increase from the cone tip to the cone tail, ensuring that the flow rate at the cone tip is greater than that at the cone tail. Fluid flows out through the openings in the two baffles and the discharge channels 3242 on either side, with the discharge resistance increasing closer to the cone tip. This design ensures uniform flow at all discharge locations and prevents localized flow deviations. Furthermore, this conical structure avoids the formation of a stagnant zone at the bottom of the discharge chamber.

[0094] According to the size of the adsorption tower and the processing scale, the mixing-distribution internal component 3 can be divided into multiple blocks of equal area, such as Figure 6 As shown, to facilitate installation of internal components and uniform fluid distribution, each internal component is separated by a partition plate 4, and each internal component is independently provided with an intermediate mixer-distributor 32 and an inlet and outlet pipe 321. This design avoids the problem of uneven fluid distribution caused by the use of a single internal component due to an oversized tower equipment.

[0095] Specifically, an intermediate support tube 5 is provided in the center of the adsorption tower, and the internal components are fixed at both ends through the tower wall and the intermediate support tube 5 .

[0096] The mixing-distributing internals 3 of the adsorption tower equipment are preferably divided into 2-20 pieces of equal area.

[0097] The adsorption tower is used in the process of preparing meta-dichlorobenzene. The adsorbent is preferably used to adsorb o-dichlorobenzene and p-dichlorobenzene, and the residual liquid is meta-dichlorobenzene. The adsorption temperature is preferably 150-250°C, and the adsorption pressure is preferably 0.5-1.5MPa.

[0098] The adsorption tower is used in the process of preparing meta-dichlorobenzene. The desorbent is preferably chlorobenzene, dichlorotoluene, xylene or a mixture thereof. The desorption temperature is preferably 150-250° C., and the desorption pressure is preferably 0.5-1.5 MPa.

[0099] The above operating conditions can ensure that the adsorption is carried out in a liquid phase environment.

[0100] This embodiment provides an adsorption tower device for preparing high-purity meta-dichlorobenzene, which can be used to prepare a high-purity meta-dichlorobenzene product.

[0101] Specifically, the fresh feed enters the inlet and outlet conical distribution chamber 322 from the inlet and outlet pipes 321, and then flows into the mixing channel 3233 from the orifice opening 3223 of the orifice plate 3222; the circulating material in the adsorption tower passes through different adsorbent beds 2 and the mixing-distribution internal component 3 from top to bottom, and is then blocked by the conical mixing chamber partition 3231, and can only enter the mixing channel 3233 of the conical mixing chamber 323, and is completely mixed with the fresh feed; the evenly mixed fluid flows out through the conical mixing chamber outlet 3234 and enters the conical discharge chamber 324; the fluid flows out through the baffle opening 3243 and the discharge channel 3242 of the conical discharge chamber 324; the baffle opening 3243 has different apertures, so that the closer to the cone tip, the greater the outlet resistance is, to prevent the formation of biased flow when the fluid flows out.

[0102] Example 3

[0103] Meta-dichlorobenzene was prepared using the adsorption tower equipment described in Example 2. The adsorption tower had a diameter of 1.6 meters and contained 12 layers of adsorbent, with each layer of adsorbent having a bed height of 500 mm; the adsorbent was a 13X molecular sieve modified with calcium nitrate and potassium hydroxide. The mixing-distribution internal components were divided into four pieces of equal area, and the orifice plate of the inlet and outlet conical distribution chamber of the intermediate mixing-distributor had three rows of holes, with an aperture of 3.5 mm, a hole spacing of 21 mm, and a calculated hole flow rate of 3.0-9.0 m / s. The mixing channel flow rate of the conical mixing chamber of the intermediate mixing-distributor was designed to be 2.0 m / s, and the flow rate at the outlet of the conical mixing chamber was 1.0 m / s. The conical discharge chamber baffle had three rows of holes, with an aperture of 2.0 mm at the tip, 10.0 mm at the tail, and 5.0 mm in the middle.

[0104] 10 kg of raw material mixed dichlorobenzene (o-dichlorobenzene: p-dichlorobenzene: m-dichlorobenzene = 3:3:4) enters the adsorption tower through the inlet and outlet pipes 321. The adsorption temperature is 200°C and the adsorption pressure is 1.0 MPa. During desorption, the adsorption tower is filled with the desorbent 3,4-dichlorotoluene. The desorption temperature is 250°C and the desorption pressure is 0.5 MPa.

[0105] The collected raffinate was o-dichlorobenzene and p-dichlorobenzene, weighing 6.11 kg; the collected desorption liquid was m-dichlorobenzene, with a purity of 99.65% and a weight of 3.89 kg. The calculated recovery rate of m-dichlorobenzene was 97.25%.

[0106] Example 4

[0107] Meta-dichlorobenzene was prepared using the adsorption tower equipment described in Example 2. The adsorption tower had a diameter of 3.6 meters and contained 6 layers of adsorbent, with each layer of adsorbent having a bed height of 500 mm; the adsorbent was a 13X molecular sieve modified with calcium nitrate and lithium hydroxide. The mixing-distribution internal components were divided into 8 pieces of equal area, and the orifice plate of the inlet and outlet conical distribution chamber of the intermediate mixing-distributor had 3 rows of holes, with an aperture of 5.0 mm, a hole spacing of 30 mm, and a calculated hole flow rate of 5.0-10.0 m / s. The mixing channel flow rate of the conical mixing chamber of the intermediate mixing-distributor was designed to be 2.5 m / s, and the flow rate at the outlet of the conical mixing chamber was 1.5 m / s. The conical discharge chamber baffle had 3 rows of holes, with an aperture of 2.0 mm at the tip, 15.0 mm at the tail, and 8.0 mm in the middle.

[0108] 100 kg of raw material mixed dichlorobenzene (o-dichlorobenzene: p-dichlorobenzene: m-dichlorobenzene = 3:3:4) enters the adsorption tower through the inlet and outlet pipes 321, with an adsorption temperature of 160°C and an adsorption pressure of 0.8 MPa. During desorption, the adsorption tower is filled with the desorbent 3,4-dichlorotoluene, with a desorption temperature of 180°C and a desorption pressure of 0.6 MPa.

[0109] The collected raffinate was m-dichlorobenzene with a purity of 99.55% and a weight of 38.2 kg. The calculated recovery rate of m-dichlorobenzene was 95.5%. The collected desorption liquid (o-dichlorobenzene and p-dichlorobenzene) weighed 61.8 kg.

[0110] Example 5

[0111] Meta-dichlorobenzene was prepared using the adsorption tower equipment described in Example 2. The adsorption tower had a diameter of 2.5 meters and contained 10 layers of adsorbent, with each layer of adsorbent having a bed height of 500 mm. The adsorbent was a ZSM-5 molecular sieve modified with sodium nitrate and lithium hydroxide. The mixing-distribution internal components were divided into 6 pieces of equal area. The orifice plate of the inlet and outlet conical distribution chamber of the intermediate mixing-distributor had 3 rows of holes, with an aperture of 10.0 mm, a hole spacing of 50 mm, and a calculated hole flow rate of 3.0-8.0 m / s. The mixing channel flow rate of the conical mixing chamber of the intermediate mixing-distributor was designed to be 1.8 m / s, and the flow rate at the outlet of the conical mixing chamber was 1.1 m / s. The baffle of the conical discharge chamber had 3 rows of holes, with an aperture of 3.0 mm at the tip, 12.0 mm at the tail, and 6.0 mm in the middle.

[0112] 50 kg of raw material mixed dichlorobenzene (o-dichlorobenzene: p-dichlorobenzene: m-dichlorobenzene = 3:3:4) enters the adsorption tower through the inlet and outlet pipes 321, with an adsorption temperature of 180°C and an adsorption pressure of 1.0 MPa. During desorption, the adsorption tower is filled with desorbent chlorobenzene, with a desorption temperature of 200°C and a desorption pressure of 0.6 MPa.

[0113] The collected raffinate was o-dichlorobenzene and p-dichlorobenzene, weighing 30.7 kg; the collected desorption liquid was m-dichlorobenzene, with a purity of 99.73% and a weight of 19.3 kg. The calculated recovery rate of m-dichlorobenzene was 96.5%.

[0114] Example 6

[0115] Paraxylene was prepared using the adsorption tower equipment described in Example 2. The adsorption tower had a diameter of 3.5 meters and contained 12 layers of adsorbent, with each layer of adsorbent having a bed height of 550 mm; the adsorbent was a 13X molecular sieve modified with potassium nitrate and lithium hydroxide. The mixing-distribution internal components were divided into 12 blocks of equal area, and the orifice plate of the inlet and outlet conical distribution chamber of the intermediate mixing-distributor had three rows of holes, with an aperture of 10.0 mm, a hole spacing of 50 mm, and a calculated hole flow rate of 3.0-8.0 m / s. The mixing channel flow rate of the conical mixing chamber of the intermediate mixing-distributor was designed to be 1.8 m / s, and the flow rate at the outlet of the conical mixing chamber was 1.1 m / s. The conical discharge chamber baffle had three rows of holes, with an aperture of 3.0 mm at the tip, 12.0 mm at the tail, and 6.0 mm in the middle.

[0116] 50 kg of raw material mixed xylene (o-xylene: p-xylene: m-xylene = 3.5:2.5:4) enters the adsorption tower through the inlet and outlet pipes 321, with an adsorption temperature of 175°C and an adsorption pressure of 0.8 MPa. During desorption, the adsorption tower is filled with desorbent toluene, with a desorption temperature of 180°C and a desorption pressure of 0.6 MPa.

[0117] The collected raffinate was o-xylene and m-xylene, weighing 37.9 kg; the collected desorption liquid was p-xylene, with a purity of 99.8% and a weight of 12.0 kg. The calculated p-xylene recovery rate was 96.0%.

[0118] In the present invention, there are no static areas at the top or bottom of the internal components, ensuring sufficient fluid flow. Simultaneously, different hole flow rate designs are employed to ensure that the fluid within the adsorption tower is fully mixed with the inlet and outlet fluids, without backmixing or biased flow. Furthermore, the present invention utilizes a liquid-phase adsorption process, avoiding the equipment investment and energy consumption required for fluid vaporization and condensation, significantly reducing production costs. Using the adsorption tower apparatus of the present invention, a meta-dichlorobenzene product with a purity greater than 99.5% and a yield greater than 95% can be obtained. The adsorption tower apparatus of the present invention can also be applied to the production of high-purity para-xylene.

[0119] The above description of the embodiments is intended to facilitate understanding and use of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A liquid phase adsorption separation system, characterized in that: The invention comprises an adsorption tower body (1) and three or more adsorbent beds (2) arranged in the adsorption tower body (1), wherein a mixing-distribution internal component (3) is provided between two adjacent adsorbent beds (2); The mixing-distributing internal component (3) comprises an upper supporting grid (31), a middle mixing-distributor (32) and a lower supporting grid (33); The intermediate mixing-distributor (32) comprises an inlet and outlet pipe (321), an inlet and outlet conical distribution chamber (322), a conical mixing chamber (323), and a conical discharge chamber (324), wherein the inlet and outlet conical distribution chamber (322), the conical mixing chamber (323), and the conical discharge chamber (324) are all arranged between the upper support grid (31) and the lower support grid (33); The inlet and outlet pipes (321) pass through the upper support grid (31) and the adsorption tower body (1) and are in communication with the outside world; the inlet and outlet conical distribution chamber (322) is in communication with the inlet and outlet pipes (321); the conical mixing chamber (323) is arranged below the inlet and outlet conical distribution chamber (322) and is in communication with the inlet and outlet conical distribution chamber (322); and the conical discharge chamber (324) is arranged below the conical mixing chamber (323) and is in communication with the conical mixing chamber (323); The inlet and outlet conical distribution chamber (322) includes two perforated plates (3222), each of which has 3 to 6 rows of holes with a hole diameter of 2 to 25 mm; The conical discharge chamber (324) comprises two inclined conical discharge chamber baffles (3241), the two conical discharge chamber baffles (3241) are provided with 3-6 rows of holes, the hole diameters of the holes gradually increase from the cone tip to the cone tail, the hole diameters of the holes near the cone tip are 2-5 mm, the hole diameters of the holes near the cone tail are 10-15 mm, and the hole diameters of the holes in the middle are 5-10 mm; The conical mixing chamber (323) comprises two conical mixing chamber partitions (3231) and two inclined conical mixing chamber baffles (3232); One end of the conical mixing chamber partition (3231) is fixed, and the other end is connected to the conical mixing chamber baffle (3232); a mixing channel (3233) is formed between the conical mixing chamber baffle (3232) and the inlet and outlet conical distribution chamber (322); and a conical mixing chamber outlet (3234) is formed between the bottoms of the two conical mixing chamber baffles (3232); A discharge channel (3242) is formed between the conical discharge chamber baffle (3241) of the conical discharge chamber (324) and the conical mixing chamber (323).

2. The liquid phase adsorption separation system according to claim 1, characterized in that: The inlet and outlet conical distribution chamber (322) includes a half pipe (3221) and two perforated plates (3222); The two perforated plates (3222) form a conical structure with a cone angle of 30°-60°. The half pipe (3221) is arranged at the top of the conical structure and is connected to the inlet and outlet pipes (321). The hole spacing of each perforated plate (3222) is 4-15 times the hole diameter, and the perforated hole flow rate is 3.0-10.0 m / s.

3. The liquid phase adsorption separation system according to claim 1, characterized in that: The flow rate of the mixing channel is 1.5-3.5 m / s, and the flow rate of the conical mixing chamber outlet (3234) is 0.5-1.5 m / s.

4. The liquid phase adsorption separation system according to claim 1, characterized in that: The outlet flow rate of the discharge channel (3242) is 0.1-0.5 m / s; The flow rate of the opening holes at the cone tail of the two conical discharge chamber baffles (3241) is 0.1-0.5 m / s, the flow rate of the opening holes at the cone tip is 0.5-1.0 m / s, and the flow rate of the opening holes in the middle is between the former two.

5. The liquid phase adsorption separation system according to claim 1, characterized in that: The mixing-distributing internal component (3) is divided into 2-20 sub-internal components of equal area, each sub-internal component is separated by a partition plate (4), and each sub-internal component is provided with an intermediate mixing-distributor (32); The adsorbent bed layer (2) has 3 to 20 layers, and the adsorbent bed layer (2) is filled with adsorbent.

6. Use of the liquid phase adsorption separation system according to any one of claims 1 to 5, characterized in that: The liquid phase adsorption separation system is used to produce high-purity meta-dichlorobenzene, comprising the following steps: Fresh feed enters the inlet and outlet conical distribution chamber (322) from the first layer of inlet and outlet pipes (321), and then flows into the mixing channel (3233) from the perforated plate (3222) of the inlet and outlet conical distribution chamber (322). The circulating material in the adsorption tower body (1) passes through different adsorbent beds (2) and the mixing-distribution internal components (3) from top to bottom, and is then blocked by the conical mixing chamber baffle (3232) and can only enter the mixing channel (3233) of the conical mixing chamber (323), where it is completely and evenly mixed with the fresh feed. The evenly mixed fluid flows out through the conical mixing chamber outlet (3234) and enters the conical discharge chamber (324). The fluid flows out through the opening of the conical discharge chamber baffle (3241) and the discharge channel (3242). The fresh feed and the recycle material both contain o-dichlorobenzene, p-dichlorobenzene and m-dichlorobenzene; The fresh feed and the circulating material are adsorbed by at least N layers of adsorbent bed (2), and the residual liquid after adsorption is extracted from the feed and discharge pipe (321) of the N+1 layer; The N is not less than 3.

7. Use of the liquid phase adsorption separation system according to claim 6, characterized in that: A circulation pipeline and a circulation pump are provided outside the adsorption tower body (1), and the circulation pipeline and the circulation pump circulate the fluid flowing out from the bottom head of the adsorption tower body (1) to the upper part as circulating material.

8. Use of the liquid phase adsorption separation system according to claim 6, characterized in that: The adsorbent filled in the adsorbent bed (2) is an adsorbent for adsorbing o-dichlorobenzene and p-dichlorobenzene or an adsorbent for adsorbing m-dichlorobenzene, with an adsorption temperature of 150-250° C. and an adsorption pressure of 0.5-1.5 MPa.

9. Use of the liquid phase adsorption separation system according to claim 8, characterized in that: The adsorbent is an X-type molecular sieve, a Y-type molecular sieve, a ZSM series molecular sieve, or a SAPO series molecular sieve modified with a group IA or group IIA metal.

10. Use of the liquid phase adsorption separation system according to claim 6, characterized in that: The following steps are also included: 50 to 250 seconds after the start of fresh feeding, the fresh feeding is stopped, and the desorbent enters the inlet and outlet conical distribution chamber (322) from the first layer inlet and outlet pipe (321), and then desorbs the o-dichlorobenzene and p-dichlorobenzene or m-dichlorobenzene adsorbed in the adsorbent along the same channel as the fresh feeding; The desorbent is chlorobenzene, dichlorotoluene, xylene or a mixture thereof; The desorption temperature is 150-250°C and the desorption pressure is 0.5-1.5 MPa; The desorbed liquid is drawn out from the inlet and outlet pipe (321) of the N+1 layer; The N is not less than 3.

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