Method and apparatus for preparing purified 1, 4-butanediol composition

Abstract

The invention discloses a method and an apparatus for preparing a purified 1, 4-butanediol composition. The method comprises the following steps: providing a dividing wall column; a 1, 4-butanediol composition to be purified is introduced into the dividing wall column, and the purified 1, 4-butanediol composition is prepared through the dividing wall column; the 1, 4-butanediol composition to be purified is prepared from gamma-butyrolactone, dimethyl succinate and 1, 4-butanediol. Effective separation and purification can be realized by only adopting one dividing wall column, so that not only is the equipment investment saved, but also the energy consumption is reduced.

Description

Technical Field

[0001] This invention relates to a method and apparatus for preparing purified 1,4-butanediol compositions. Background Technology

[0002] Ester hydrogenation is the mainstream process for producing 1,4-butanediol (BDO), and there are generally two routes: ① Chemical method, which produces maleic anhydride from butane and then hydrogenates the maleic anhydride. This process has a wide range of raw material sources and is suitable for large-scale production; ② Biological method, which produces 1,4-butanediol from bio-based succinic acid by esterification and then hydrogenation. This process uses biomass raw materials and is green and low-carbon.

[0003] In both of the above-mentioned process routes for producing 1,4-butanediol (BDO) by ester hydrogenation, the products of the ester hydrogenation reaction contain γ-butyrolactone (GBL), dimethyl succinate (DMS), and 1,4-butanediol (BDO), and may also contain n-butanol (BUOH). This mixture needs to be further separated by distillation to obtain 1,4-butanediol (BDO) as pure as possible.

[0004] The distillation separation of the above-mentioned ester hydrogenation reaction product mixture is difficult, especially dimethyl succinate (DMS), which is difficult to separate effectively from 1,4-butanediol (BDO). Traditional processes require at least two distillation columns to achieve the above separation and purification, resulting in high energy consumption and large equipment investment. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies in the purification of 1,4-butanediol (BDO), namely, the difficulty in effectively separating dimethyl succinate (DMS) from 1,4-butanediol (BDO), or the complexity and high cost of the separation process. Therefore, this invention provides a method and apparatus for preparing purified 1,4-butanediol compositions. The method of this invention can achieve effective separation and purification using only one partition wall column, saving on equipment investment and reducing energy consumption.

[0006] In this invention, the 1,4-butanediol composition to be purified comprises 1,4-butanediol (BDO), and at least dimethyl succinate (DMS) and γ-butyrolactone (GBL). The inventors have discovered that DMS and GBL form an azeotrope, the presence of which affects the relative volatility of DMS and BDO, thus influencing the ease of separation and purification of BDO in the system. Furthermore, the current lack of relevant azeotropic data for reference increases the operational difficulty. Therefore, this invention creatively utilizes a partitioned-wall column for preparing the purified 1,4-butanediol composition, achieving separation and purification using only one partitioned-wall column, saving on equipment investment and reducing energy consumption.

[0007] Specifically, the present invention solves the above-mentioned technical problems through the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a purified 1,4-butanediol composition, comprising the following steps:

[0009] Provide the adjacent tower;

[0010] The 1,4-butanediol composition to be purified is passed into the partition wall column, and the purified 1,4-butanediol composition is obtained by passing it through the partition wall column.

[0011] The 1,4-butanediol composition to be purified includes γ-butyrolactone, dimethyl succinate, and 1,4-butanediol.

[0012] [The neighboring tower]

[0013] In this invention, the Dividing Wall Column (DWC), also known as a partition column, is essentially a vertical partition installed inside a traditional distillation column.

[0014] In this invention, the theoretical plate number (N, also known as the theoretical stage) of the partition column refers to the minimum number of equilibrium units (mass transfer units) required to achieve a specified separation effect under ideal conditions in a separation process (such as a distillation column, packed column, or chromatographic column). Each theoretical plate is considered an ideal layer that has completely achieved gas-liquid or stationary-mobile phase thermodynamic equilibrium.

[0015] The total theoretical number of plates in the adjacent tower is equal to the theoretical number of plates in the top separation zone, the theoretical number of plates in the first separation zone, the theoretical number of plates in the second separation zone, and the theoretical number of plates in the bottom separation zone.

[0016] In this invention, the partition wall tower may, from top to bottom, include a top separation zone, a partition zone, and a bottom separation zone. The partition zone is divided into a first separation zone and a second separation zone by partitions. The first separation zone may have a feed inlet, and the second separation zone may have a first side outlet. The purified 1,4-butanediol composition is collected from the first side outlet. The top separation zone refers to the area above the partition zone inside the partition wall tower, and the bottom separation zone refers to the area below the partition zone inside the partition wall tower.

[0017] In some embodiments, the 1,4-butanediol composition to be purified further includes n-butanol (BUOH), and the top separation zone is further provided with a second side stream outlet; the n-butanol composition is collected from the top of the partition column, and the azeotrope is collected from the second side stream outlet, the azeotrope including dimethyl succinate and γ-butyrolactone. When the system to be purified further includes n-butanol, the purification and separation difficulty is further increased. To achieve the separation of n-butanol while using a partition column to separate other components, the present invention adds a second side stream outlet to the top separation zone. In other embodiments, the 1,4-butanediol composition to be purified does not include n-butanol, and the azeotrope is collected from the top of the partition column; the azeotrope includes dimethyl succinate and γ-butyrolactone.

[0018] In this invention, the specific operation of collecting the stream from the top of the partition column includes: the gaseous stream flows out from the gaseous outlet at the top of the partition column, sequentially enters a condenser and a collector, a portion of the stream flowing out from the collector is refluxed back to the top separation zone through the top reflux inlet, and the other portion is collected. When the system to be purified further includes n-butanol, the stream collected from the top of the column is a n-butanol composition; when the system to be purified does not include n-butanol, the stream collected from the top of the column is an azeotrope of dimethyl succinate and γ-butyrolactone.

[0019] In this invention, the total theoretical number of trays in the partition tower can be 32-160, preferably 53-115.

[0020] In some specific implementations, the total theoretical number of plates in the partition tower is 32, 45, 52, 53, 56, 61, 66, 70, 75, 80, 94, 105, 108, 115, or 120.

[0021] In this invention, the number of theoretical plates in the first separation zone can be 5-40, preferably 10-40, and more preferably 15-30.

[0022] In some specific implementations, the number of theoretical plates in the first separation zone is 5, 10, 15, 24, 32, 36, or 40.

[0023] In this invention, the feed inlet may be located at the 5th to 25th theoretical plate from top to bottom in the first separation zone, for example, at the 12th theoretical plate.

[0024] In this invention, the number of theoretical plates in the second separation zone can be 5-40, preferably 10-40, and more preferably 15-30.

[0025] In some specific implementations, the number of theoretical plates in the second separation zone is 5, 10, 14, 15, 16, 24, 28, 30, 36, or 40.

[0026] In this invention, the first side outlet can be located at the 5th to 25th block from top to bottom in the second separation zone, preferably at the 10th to 15th block, for example at the 12th theoretical plate.

[0027] In this invention, the number of theoretical plates in the top separation zone can be 5-50, preferably 12-35.

[0028] In some specific implementations, the number of theoretical plates in the top separation zone is 5, 8, 10, 12, 15, 17, 18, 22, 32, 33, 35, or 50.

[0029] In this invention, the theoretical number of plates in the bottom separation zone can be 5-30, preferably 8-20, for example 5, 8, 10, 15, 16, 20 or 30.

[0030] In this invention, the top separation zone may also be provided with a second side stream outlet. Preferably, the second side stream outlet is located at the 2nd to 20th theoretical plate from top to bottom in the top separation zone, and more preferably at the 7th to 15th theoretical plate from top to bottom in the top separation zone. The main purpose of providing the second side stream outlet is to accommodate systems containing n-butanol.

[0031] In some specific implementations, the second side line outlet is located at the 2nd, 5th, 7th, 10th, 14th, 15th, or 20th theoretical plate from top to bottom in the top separation zone.

[0032] In some preferred embodiments, the number of theoretical plates in the first separation zone is 10-40, the number of theoretical plates in the second separation zone is 10-40, the number of theoretical plates in the top separation zone is 12-35, and the number of theoretical plates in the bottom separation zone is 8-20.

[0033] In some preferred embodiments, the 1,4-butanediol composition to be purified further includes n-butanol, and the top separation zone is further provided with a second side stream outlet located at the 7th-15th theoretical plate from top to bottom in the top separation zone. The number of theoretical plates in the first separation zone is 10-40, the number of theoretical plates in the second separation zone is 10-40, the number of theoretical plates in the top separation zone is 12-35, and the number of theoretical plates in the bottom separation zone is 8-20.

[0034] In this invention, the position of the partition can satisfy h / D=0.15-0.7, preferably h / D=0.15-0.5, further satisfy h / D=0.15-0.49, further satisfy h / D=0.35-0.48, and more preferably satisfy h / D=0.42-0.48, where h is the maximum width of the first separation zone in the horizontal direction, and D is the inner diameter of the partition tower.

[0035] In some specific implementations, the position of the partition plate satisfies, for example, h / D=0.37, h / D=0.40, h / D=0.43, h / D=0.47 or h / D=0.48, where h is the maximum width of the first separation zone in the horizontal direction and D is the inner diameter of the partition tower.

[0036] In this invention, the inner diameter of the partition tower can be selected according to the production scale. In some embodiments, the inner diameter D of the partition tower is 1300-3500 mm, for example, D = 1300 mm, 1400 mm, 1500 mm, 1600 mm, 1700 mm, 1800 mm, 2000 mm, 2100 mm, 2700 mm, 3000 mm, 3400 mm, or 3500 mm. The inner diameter of the partition tower here corresponds to a production scale of 30,000 tons of BDO per year.

[0037] In this invention, the form of the partition tower and other necessary components can be conventional in the art.

[0038] In some embodiments, the partition tower may be a packed tower. The packing material for the partition tower is preferably plate corrugated structured packing or wire mesh structured packing; for example, Mellapak series, Mellapak Plus series, BX or BX Plus packing.

[0039] In some implementations, the condenser of the partition tower may be a U-tube condenser, a hammerhead condenser, a horizontal shell-side condenser, or a vertical tube-side condenser.

[0040] In some embodiments, the reboiler of the partition tower may be a falling film reboiler, a forced circulation reboiler, or a thermosiphon reboiler, preferably a falling film reboiler.

[0041] In some implementations, the pump for the partition tower may be a centrifugal pump, a reciprocating pump, a gear pump, or a canned motor pump, with a centrifugal pump being preferred.

[0042] In some implementations, the storage tank of the partition tower can be a vertical tank or a horizontal tank, preferably a horizontal tank.

[0043] [The 1,4-butanediol composition to be purified]

[0044] In this invention, the mass percentage of γ-butyrolactone in the 1,4-butanediol composition to be purified can be 5%-30%, preferably 9%-15%, for example 9.11%, 11.3% or 12.11%.

[0045] In this invention, the mass percentage of dimethyl succinate in the 1,4-butanediol composition to be purified can be 0.1%-15%, preferably 1%-10%, for example 1.12%, 5.12% or 8.12%.

[0046] In this invention, the mass percentage of 1,4-butanediol in the 1,4-butanediol composition to be purified can be 55%-95%, preferably 70%-80%, for example 74.33%, 75.66% or 79.57%.

[0047] In this invention, the mass percentage of n-butanol in the 1,4-butanediol composition to be purified can be 0-10%, preferably 0-5%, for example 0, 1.05% or 1.11%.

[0048] In this invention, the above-mentioned mass percentage refers to the mass percentage of the 1,4-butanediol composition to be purified.

[0049] In this invention, the 1,4-butanediol composition to be purified can be derived from the reaction product of the ester hydrogenation process for producing 1,4-butanediol.

[0050] The process for producing 1,4-butanediol by ester hydrogenation is a well-known process in the art, for example, the content disclosed in patent application CN103946201A can be referred to.

[0051] The ester hydrogenation process can be a gas-phase or liquid-phase ester hydrogenation process.

[0052] The raw materials for the ester hydrogenation process can be selected from one or more of succinic acid, succinic anhydride, maleic acid, and maleic anhydride.

[0053] The raw material for the ester hydrogenation process can be a monoester or a polyester.

[0054]

Preparation Method Parameters

[0055] In this invention, the reflux rate / BDO output rate can be 1-10, preferably 1-5, and more preferably 2-3. The reflux rate / BDO output rate refers to the ratio of the reflux rate to the BDO output rate, where the reflux rate is the mass flow rate of the top reflux from the partition column, and the BDO output rate is the mass flow rate of the purified 1,4-butanediol composition.

[0056] In some specific implementations, the return flow / BDO output is, for example, 1.65, 1.66, 1.99, 2.12, 2.13, 2.25, 2.28, 2.31, 2.32, 2.56, 2.71, 2.93, 2.97, 3.55 or 4.12, 6.86, 7.11, 8.11 or 8.31.

[0057] In this invention, the partition ratio R L It can be 0.01-0.4, preferably 0.05-0.2, where R L The allocation ratio R is the ratio of the amount allocated to the first separation zone to the amount extracted from the top separation zone, where the amount extracted from the top separation zone is the total mass flow rate of the descending liquid extracted from the top separation zone; and the allocation amount to the first separation zone is the mass flow rate of the descending liquid extracted from the top separation zone allocated to the first separation zone. In this invention, the allocation ratio R... L The design can be based on the theoretical number of trays, the location of the baffles, and other process parameters (such as temperature and pressure) in each zone of the adjacent tower.

[0058] In this invention, the specific operation of the material distribution in the partition zone may include: all the descending liquid in the top separation zone is drawn out through the top separation zone outlet located at the lower part of the top separation zone, according to the designed distribution ratio R. L A portion of the extracted liquid from the top separation zone descends into the first separation zone through the first separation zone inlet, while the other portion of the extracted liquid from the top separation zone descends into the second separation zone through the second separation zone inlet.

[0059] In some specific implementations, the partition's distribution ratio R L For example, 0.06, 0.08, 0.09, 0.10, 0.11, 0.12, 0.13, 0.14, 0.15, 0.17, 0.18, or 0.19.

[0060] In this invention, the operating temperature at the top of the adjacent tower can be 100-170℃, preferably 100-150℃.

[0061] In some specific embodiments, the operating temperature at the top of the adjacent tower is, for example, 110.6℃, 111℃, 111.2℃, 111.3℃, 125.5℃, 126.1℃, 139.7℃, 140.1℃, 140.2℃, 140.4℃, 140.7℃, 140.9℃, 156.8℃, 156.9℃, or 157.2℃.

[0062] In this invention, the absolute operating pressure of the partition tower can be 5-50 kPaA, preferably 10-30 kPaA, for example 10 kPaA or 30 kPaA.

[0063] In this invention, the operating temperature of the bottom of the partition tower can be 130-200℃, preferably 160-200℃, for example 172.9℃, 173.1℃, 174.1℃, 174.2℃, 174.3℃, 174.5℃, 174.8℃, 198.1℃, 198.3℃, 198.4℃, 198.9℃, 199.2℃, 199.3℃, 199.6℃ or 199.9℃.

[0064] In a second aspect, the present invention provides an apparatus for preparing a purified 1,4-butanediol composition, comprising a partitioned column, wherein the partitioned column comprises, from top to bottom, a top separation zone, a partition zone, and a bottom separation zone, wherein the partition zone is divided into a first separation zone and a second separation zone by a partition.

[0065] The first separation zone is provided with a feed inlet for introducing the 1,4-butanediol composition to be purified; the 1,4-butanediol composition to be purified includes γ-butyrolactone, dimethyl succinate and 1,4-butanediol;

[0066] The second separation zone is provided with a first side outlet for collecting the purified 1,4-butanediol composition.

[0067] In some embodiments, the top separation zone is further provided with a second side outlet, which is used to collect azeotropes, including dimethyl succinate and γ-butyrolactone, when the 1,4-butanediol composition to be purified also includes n-butanol.

[0068] Preferably, the second side stream outlet is located at the 2nd to 20th theoretical plate from top to bottom in the top separation zone, and more preferably at the 7th to 15th theoretical plate from top to bottom in the top separation zone. The main purpose of setting the second side stream outlet is to accommodate systems containing n-butanol.

[0069] In some specific implementations, the second side line outlet is located at the 2nd, 5th, 7th, 10th, 14th, 15th, or 20th theoretical plate from top to bottom in the top separation zone.

[0070] In this invention, the total theoretical number of trays in the partition tower can be 32-160, preferably 53-115.

[0071] In some specific implementations, the total theoretical number of plates in the partition tower is 32, 45, 52, 53, 56, 61, 66, 70, 75, 80, 94, 105, 108, 115, or 120.

[0072] In this invention, the number of theoretical plates in the first separation zone can be 5-40, preferably 10-40, and more preferably 15-30.

[0073] In some specific implementations, the number of theoretical plates in the first separation zone is 5, 10, 15, 24, 32, 36, or 40.

[0074] In this invention, the feed inlet may be located at the 5th to 25th theoretical plate from top to bottom in the first separation zone, for example, at the 12th theoretical plate.

[0075] In this invention, the number of theoretical plates in the second separation zone can be 5-40, preferably 10-40, and more preferably 15-30.

[0076] In some specific implementations, the number of theoretical plates in the second separation zone is 5, 10, 14, 15, 16, 24, 28, 30, 36, or 40.

[0077] In some implementations, the first side outlet is located at the 5th to 25th section from top to bottom in the second separation zone, preferably at the 10th to 15th section, such as the 12th theoretical plate.

[0078] In this invention, the number of theoretical plates in the top separation zone can be 5-50, preferably 12-35.

[0079] In some specific implementations, the number of theoretical plates in the top separation zone is 5, 8, 10, 12, 15, 17, 18, 22, 32, 33, 35, or 50.

[0080] In this invention, the theoretical number of plates in the bottom separation zone can be 5-30, preferably 8-20, for example 5, 8, 10, 15, 16, 20 or 30.

[0081] In some preferred embodiments, the number of theoretical plates in the first separation zone is 10-40, the number of theoretical plates in the second separation zone is 10-40, the number of theoretical plates in the top separation zone is 12-35, and the number of theoretical plates in the bottom separation zone is 8-20.

[0082] In some preferred embodiments, the top separation zone is further provided with a second side line outlet, which is located at the 7th to 15th theoretical plate from top to bottom in the top separation zone. The number of theoretical plates in the first separation zone is 10-40, the number of theoretical plates in the second separation zone is 10-40, the number of theoretical plates in the top separation zone is 12-35, and the number of theoretical plates in the bottom separation zone is 8-20.

[0083] In this invention, the position of the partition can satisfy h / D=0.15-0.7, preferably h / D=0.15-0.5, further satisfy h / D=0.15-0.49, further satisfy h / D=0.35-0.48, and more preferably satisfy h / D=0.42-0.48, where h is the maximum width of the first separation zone in the horizontal direction, and D is the inner diameter of the partition tower.

[0084] In some specific implementations, the position of the partition plate satisfies, for example, h / D=0.37, h / D=0.4, h / D=0.43, h / D=0.47 or h / D=0.48, where h is the maximum width of the first separation zone in the horizontal direction and D is the inner diameter of the partition tower.

[0085] In this invention, preferably, the inner diameter D of the partition tower is 1300-3500 mm, more preferably, D is 1300-2100 mm.

[0086] In some specific implementations, the inner diameter D of the partition tower is 1400 mm, 1500 mm, 1600 mm, 1700 mm, 1800 mm, 2000 mm, 2100 mm, 2700 mm, 3000 mm, 3400 mm or 3500 mm.

[0087] In this invention, the form of the partition tower and other necessary components can be conventional in the art.

[0088] In some embodiments, the partition tower may be a packed tower. The packing material for the partition tower is preferably plate corrugated structured packing or wire mesh structured packing; for example, Mellapak series, Mellapak Plus series, BX or BX Plus packing.

[0089] In some implementations, the condenser of the partition tower may be a U-tube condenser, a hammerhead condenser, a horizontal shell-side condenser, or a vertical tube-side condenser.

[0090] In some embodiments, the reboiler of the partition tower may be a falling film reboiler, a forced circulation reboiler, or a thermosiphon reboiler, preferably a falling film reboiler.

[0091] In some implementations, the pump for the partition tower may be a centrifugal pump, a reciprocating pump, a gear pump, or a canned motor pump, with a centrifugal pump being preferred.

[0092] In some implementations, the storage tank of the partition tower can be a vertical tank or a horizontal tank, preferably a horizontal tank.

[0093] The positive and progressive effects of this invention are as follows:

[0094] (1) The present invention uses partition wall tower technology to prepare purified 1,4-butanediol compositions, mainly targeting 1,4-butanediol compositions containing DMS, and achieves effective separation and purification;

[0095] (2) The method of the present invention requires only one partition tower, and the entire purification process is operated in a single partition tower. Compared with the traditional multi-tower process, it greatly simplifies the process flow and reduces equipment investment and floor space.

[0096] (3) The heat and mass coupling in the partition tower of the present invention enhances the heat and mass transfer efficiency and significantly reduces the process energy consumption;

[0097] (4) This invention is applicable to different material systems containing 1,4-butanediol, which may contain n-butanol or not, and can achieve the purification of 1,4-butanediol compositions, ensuring the continuity and stability of the process. Attached Figure Description

[0098] Figure 1 The process flow diagrams are shown in Examples 1 and 2.

[0099] Figure 2 This is a cross-sectional view of the partition tower in this invention;

[0100] Figure 3 This is a process flow diagram from Example 3;

[0101] Figure 4 The process flow diagrams are for Comparative Examples 1 to 3;

[0102] The attached figures are labeled as follows:

[0103] The neighboring tower is 100;

[0104] Feed inlet 101, first side line outlet 102, second side line outlet 103, top gas phase outlet 104, top reflux inlet 105, top separation zone outlet 106, first separation zone inlet 107, second separation zone inlet 108, bottom liquid phase outlet 109, bottom reflux inlet 110;

[0105] 200 partitions;

[0106] Condenser 300;

[0107] Reboiler 400. Detailed Implementation

[0108] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0109] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0110] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0111] In the following examples and comparative examples,

[0112] Dividing Wall Column (DWC), also known as a partition column, is essentially a vertical partition placed inside a traditional distillation column.

[0113] The theoretical plate number (N, also known as the theoretical stage) of a column refers to the minimum number of equilibrium units (mass transfer units) required under ideal conditions to achieve a specified separation effect in a separation process (such as distillation columns, packed columns, and chromatographic columns). Each theoretical plate is considered an ideal layer that has achieved complete thermodynamic equilibrium between the gas and liquid phases or between the stationary and mobile phases.

[0114] The total theoretical number of plates in the adjacent tower = the theoretical number of plates in the top separation zone + the theoretical number of plates in the first separation zone + the theoretical number of plates in the second separation zone + the theoretical number of plates in the bottom separation zone.

[0115] The reflux / BDO output refers to the ratio of the mass flow rate of the overhead reflux (overhead stream) from the adjacent column to the mass flow rate of the purified 1,4-butanediol composition stream.

[0116] The reflux / side stream output refers to the ratio of the mass flow rate of the top reflux (top stream) to the mass flow rate of the side stream output in a conventional distillation column.

[0117] Allocation ratio R LThis refers to the ratio of the amount allocated to the first separation zone to the amount extracted from the top separation zone, where the amount extracted from the top separation zone is the total mass flow rate of the descending liquid extracted from the top separation zone; and the amount allocated to the first separation zone is the mass flow rate of the descending liquid extracted from the top separation zone allocated to the first separation zone.

[0118] The product recovery rate of BDO is defined as the mass flow rate of BDO in the purified 1,4-butanediol composition stream / the mass flow rate of BDO in the 1,4-butanediol composition stream to be purified × 100%.

[0119] The product purity of BDO is defined as the mass flow rate of BDO in the purified 1,4-butanediol composition stream / the total mass flow rate of the purified 1,4-butanediol composition stream × 100%.

[0120] The DMS+GBL content in BDO products refers to the sum of the mass flow rates of DMS and GBL in the purified 1,4-butanediol composition stream / the total mass flow rate of the purified 1,4-butanediol composition stream × 100%.

[0121] The BDO content in an azeotrope (DMS+GBL) is calculated as: (mass flow rate of BDO in the azeotrope stream / mass flow rate of the azeotrope stream) × 100%.

[0122] The DMS+GBL content in n-butanol (BUOH) products refers to the sum of the mass flow rates of DMS and GBL in the overhead stream containing n-butanol / the mass flow rate of the overhead stream containing n-butanol × 100%.

[0123] Example 1

[0124] A method for preparing a purified 1,4-butanediol composition is as follows:

[0125] Taking a BDO production capacity of 30,000 tons per year as an example, the mass composition of the 1,4-butanediol composition stream to be purified (feed 1) is shown in Table 1-1:

[0126] Table 1-1

[0127]

[0128] The light components include methanol, ethanol, hydrogen, methane, tetrahydrofuran, water, toluene, xylene, dimethyl ether, carbon dioxide, and carbon monoxide; the heavy components are mainly acetals and ether oligomers, such as hydroxybutyral, acetal, 2-(4-hydroxybutoxy)tetrahydrofuran, dibutanediol, 2-methyl-BDO, and 2-ethyl-BDO. The presence of both light and heavy components has almost no impact on the separation and purification of 1,4-butanediol (BDO).

[0129] like Figure 1As shown, the 1,4-butanediol composition stream to be purified is introduced into the partition column 100 through inlet 101. All streams in the partition column 100 operate continuously, and are collected simultaneously from each outlet, specifically as follows: The overhead stream containing n-butanol and light components collected from the vapor outlet 104 of the partition column 100 is condensed by condenser 300, with a portion refluxed through the overhead reflux inlet 105, and the remainder collected as the n-butanol composition product stream. The purified 1,4-butanediol composition product stream is collected from the first side outlet 102 of the partition column 100. The azeotropic stream containing γ-butyrolactone (GBL) and dimethyl succinate (DMS) is collected from the second side outlet 103 in the middle of the top separation zone of the partition column 100 (between section I and section II). The descending liquid stream in the top separation zone (sections I and II) of the adjacent tower 100 is collected through the top separation zone outlet 106 located at the lower part of the top separation zone, according to the designed distribution ratio R. L The stream is divided into two streams, which are respectively distributed into the first separation zone (section III) and the second separation zone (section IV) via inlet 107 of the first separation zone and inlet 108 of the second separation zone. The stream containing heavy components is collected from the liquid phase outlet 109 of the bottom of the adjacent column 100. Part of it is heated by the reboiler 400 and then refluxed through the bottom reflux inlet 110, while the remainder is collected as residual liquid.

[0130] like Figure 1 As shown, the partition column 100 includes, from top to bottom, a top separation zone, a partition zone, and a bottom separation zone (section V). The partition zone is divided into a first separation zone (section III) and a second separation zone (section IV) by a partition 200. The top of the partition column 100 has a top gas phase outlet 104 and a top reflux inlet 105. The top separation zone also has a second side line outlet 103 and a top separation zone inlet 106. The top separation zone is divided into section I and section II from top to bottom, with the second side line outlet 103 as the boundary. The first separation zone has a feed inlet 101 and a first separation zone inlet 107, and the second separation zone has a first side line outlet 102 and a second separation zone inlet 108. The bottom of the partition column 100 has a bottom liquid phase outlet 109 and a bottom reflux inlet 110. The partition positions are as follows... Figure 2 As shown, h is the maximum horizontal width of the first separation zone, and D is the inner diameter of the partition column. The condenser 300 is a U-tube condenser, and the reboiler 400 is a falling film reboiler. Furthermore, the partition column 100 is a packed column, with Mellapk packing. The pump for the partition column 100 is a centrifugal pump. The storage tank for the partition column 100 is a horizontal tank.

[0131] Specifically, this embodiment includes 5 operating conditions, of which operating condition 1-1 is as follows:

[0132] (1) Design parameters

[0133] The inner diameter of the partition tower is D = 1700 mm, and the partition plate position satisfies h / D = 0.48. The total theoretical number of plates in the partition tower is 80 (total theoretical stage number is 80). Among them, the top separation zone is divided into section I and section II from top to bottom, with the second side line outlet as the boundary. Section I has 10 theoretical plates and section II has 12 theoretical plates. The first separation zone (section III) has 24 theoretical plates, and the feed inlet is located on the 12th theoretical plate of the first separation zone (section III) (from top to bottom). The second separation zone (section IV) has 24 theoretical plates, and the first side line outlet is located on the 12th theoretical plate of the second separation zone (section IV) of section IV (from top to bottom). The bottom separation zone (section V) has 10 theoretical plates.

[0134] (2) Operating parameters

[0135] The operating pressure at the top of the adjacent column is 10 kPaA (absolute pressure), the operating temperature at the top is 111.3℃, and the operating temperature at the bottom is 174.5℃. The overhead stream from the vapor outlet is condensed and collected, and a portion is refluxed back into the adjacent column, forming a reflux stream. The reflux rate / BDO output is 2.12. All the liquid descending from the top separation zone (Section II) is collected and distributed to the first separation zone (Section III) and the second separation zone (Section IV) on either side of the partition, with a distribution ratio R... L The allocation ratio R is 0.14. L The design needs to be determined by combining tower design parameters (such as the number of theoretical plates in each zone and the position of the baffles), tower operating parameters (such as temperature and pressure), and product separation requirements.

[0136] (3) Separation results

[0137] In the purified 1,4-butanediol composition stream collected from the first side outlet of the adjacent tower, the purity of BDO was 99.66 wt%, the yield of BDO was 98.5%, and the content of the azeotrope (DMS+GBL) in the BDO product was only 0.017 wt%. This achieved high-purity and high-yield purification of BDO and effective separation from the difficult-to-separate azeotrope (DMS+GBL).

[0138] Meanwhile, the BDO content in the azeotrope (DMS+GBL) collected from the second side outlet of the adjacent tower was only 0.001 wt%, further demonstrating that BDO and the azeotrope (DMS+GBL) were effectively separated.

[0139] Furthermore, the method in this embodiment can also purify BUOH. The azeotropic content (DMS+GBL) of the BUOH product taken from the top of the column is only 7.164 wt%, resulting in a n-butanol product with significantly improved purity.

[0140] The purity and yield of BDO products remained constant under each operating condition. The column design parameters, column operating parameters, and column separation results are shown in Table 1-2.

[0141] Table 1-2

[0142]

[0143] Compared with operating condition 1-2, operating condition 1-1 maintains the same product indicators and total theoretical number of trays, but the operating pressure increases from 10 kPaA to 30 kPaA, the reflux flow rate / BDO output rate increases, the temperature at the top and bottom of the column increases, and the position of the baffle moves towards the feed side.

[0144] Compared with operating conditions 1-3, operating conditions 1-1 maintain product indicators and reflux / BDO output, the total theoretical number of trays increases from 80 to 120, the operating pressure increases from 10 kPaA to 30 kPaA, the operating temperatures at the top and bottom of the column increase, and the position of the partition moves towards the feed side.

[0145] Compared with operating conditions 1-4, operating condition 1-1 maintains product indicators, the total theoretical number of trays decreases from 80 to 54, the reflux rate / BDO output increases, and the baffle position moves towards the feed side.

[0146] Compared with operating condition 1-5, operating condition 1-1 maintains the position of the baffle, the total number of theoretical trays increases from 80 to 108, the operating pressure increases from 10 kPaA to 30 kPaA, the reflux flow / BDO output increases, and the operating temperature at the top and bottom of the tower increases.

[0147] The purity and yield of BDO products remained unchanged under each operating condition. The column design parameters, column operating parameters and column separation results are shown in Table 1-3.

[0148] Table 1-3

[0149]

[0150] Compared to condition 1-1, in operating conditions 1-6, the theoretical number of trays in section IV is reduced to 5. If the purity and yield of the BDO product are to remain the same as in condition 1-1, the column diameter and reflux / BDO output rate need to be increased accordingly, leading to increases in both fixed and variable costs, as well as a larger equipment footprint. Otherwise, the entire distillation separation process may malfunction, resulting in abnormal situations such as excessively high reboiler temperatures or a decrease in purity due to chemical changes in the product.

[0151] Compared to condition 1-1, in operating conditions 1-7, the number of theoretical plates in stage III is reduced to 5. If the purity and yield of the BDO product are to remain the same as in condition 1-1, the column diameter and reflux / BDO output rate need to be increased accordingly. This leads to an increase in both fixed and variable costs, as well as an increase in equipment footprint. Otherwise, the entire distillation separation process may not proceed normally, resulting in abnormal situations such as excessively high reboiler temperature or a decrease in purity due to chemical changes in the product.

[0152] Compared to condition 1-1, in operating conditions 1-8, the theoretical number of trays in sections I and II is reduced to 5. If the purity and yield of the BDO product are to remain the same as in condition 1-1, the column diameter and reflux / BDO output rate need to be increased accordingly. This leads to an increase in both fixed and variable costs, as well as an increase in equipment footprint. Otherwise, the entire distillation separation process may not proceed normally, resulting in abnormal situations such as excessively high reboiler temperature or a decrease in purity due to chemical changes in the product.

[0153] Compared to condition 1-1, condition 1-9 reduces the theoretical number of trays in section V to 5. To maintain the same BDO product purity and yield as in condition 1-1, the column diameter and reflux / BDO output need to be increased accordingly, leading to higher fixed and variable costs, as well as increased equipment footprint. Otherwise, the entire distillation process may malfunction, resulting in excessively high reboiler temperatures or purity decreases due to chemical changes in the product.

[0154] Example 2

[0155] The process flow of Example 2 is the same as that of Example 1. The difference between Example 2 and Example 1 is that the composition of the 1,4-butanediol composition to be purified is different and the operating conditions are also different.

[0156] In this embodiment, the mass composition of the 1,4-butanediol composition stream (feed 2) to be purified is shown in Table 2-1:

[0157] Table 2-1

[0158]

[0159] In this embodiment, five operating conditions are included. The purity and yield of BDO products remain unchanged under each operating condition. The tower design parameters, tower operating parameters, and tower separation results are shown in Table 2-2.

[0160] In this embodiment, after separation by the adjacent column, the azeotropic content (DMS+GBL) in the BDO product was less than 0.02 wt%, while the BDO content in the azeotropic content (DMS+GBL) was only 0.001 wt%. This achieved the separation of BDO from the 1,4-butanediol composition stream containing the azeotropic system, especially the separation of BDO and DMS. The azeotropic content (DMS+GBL) in the BUOH product was only 6.463 wt%, resulting in a n-butanol product with significantly improved purity.

[0161] Table 2-2

[0162]

[0163] Comparing operating conditions 2-2 and 2-4 in Example 2 with operating conditions 1-2 and 1-4 in Example 1, it can be seen that in operating conditions 2-2 and 2-4, the h / D ratio is smaller, meaning the baffle is positioned further off-center and is more sensitive to changes in the feed. This means that when the feed composition changes, the return flow rate needs to be significantly increased to ensure product quality, which in turn leads to a significant increase in variable costs.

[0164] Example 3

[0165] In this embodiment, the mass composition of the 1,4-butanediol composition stream (feed 3) to be purified is shown in Table 3-1:

[0166] Table 3-1

[0167]

[0168] The light components include methanol, ethanol, hydrogen, methane, tetrahydrofuran, water, toluene, xylene, dimethyl ether, carbon dioxide, and carbon monoxide; the heavy components are mainly acetals and ether oligomers, such as hydroxybutyral, acetal, 2-(4-hydroxybutoxy)tetrahydrofuran, dibutanediol, 2-methyl-BDO, and 2-ethyl-BDO. The presence of both light and heavy components has almost no impact on the separation and purification of 1,4-butanediol (BDO).

[0169] like Figure 3As shown, the 1,4-butanediol composition stream to be purified is introduced into the partition column 100 through inlet 101. All streams in the partition column 100 operate continuously, and are collected simultaneously from each outlet, specifically as follows: The azeotropic stream containing light components, γ-butyrolactone (GBL), and dimethyl succinate (DMS) collected from the vapor outlet 104 at the top of the partition column 100 is condensed by condenser 300, with a portion refluxed through the top reflux inlet 105 and the remainder collected. The purified 1,4-butanediol composition product stream is collected from the first side outlet 102 of the partition column 100. The descending liquid stream in the top separation zone of the partition column 100 is collected through the top separation zone outlet 106 located at the lower part of the top separation zone, according to the designed distribution ratio R. L The stream is divided into two streams, which are respectively distributed into the first separation zone (section III) and the second separation zone (section IV) via inlet 107 of the first separation zone and inlet 108 of the second separation zone. The stream containing heavy components is collected from the liquid phase outlet 109 of the bottom of the adjacent column 100. Part of it is heated by the reboiler 400 and then refluxed through the bottom reflux inlet 110, while the remainder is collected as residual liquid.

[0170] like Figure 3 As shown, the partition column 100 includes, from top to bottom, a top separation zone, a partition zone, and a bottom separation zone (section V). The partition zone is divided into a first separation zone (section III) and a second separation zone (section IV) by a partition 200. The top of the partition column 100 has a top gas phase outlet 104 and a top reflux inlet 105. The top separation zone of the partition column 100 also has a top separation zone outlet 106, but no second side-stream outlet is added. The first separation zone has a feed inlet 101 and a first separation zone inlet 107, and the second separation zone has a first side-stream outlet 102 and a second separation zone inlet 108. The bottom of the partition column 100 has a bottom liquid phase outlet 109 and a bottom reflux inlet 110. The partition positions are as follows... Figure 2 As shown, h is the maximum horizontal width of the first separation zone, and D is the inner diameter of the partition column. The condenser 300 is a U-tube condenser, and the reboiler 400 is a falling film reboiler. Furthermore, the partition column 100 is a packed column, with Mellapk packing. The pump for the partition column 100 is a centrifugal pump. The storage tank for the partition column 100 is a horizontal tank.

[0171] This embodiment includes five operating conditions, in which the purity and yield of BDO product remain constant. The column design parameters, column operating parameters, and column separation results are shown in Table 3-2. In this embodiment, after separation by the partition column, the azeotropic content (DMS+GBL) in the BDO product is less than 0.02 wt%; at the same time, the BDO content in the azeotropic content (DMS+GBL) is only 0.001 wt%, achieving the separation of BDO from the 1,4-butanediol composition stream containing the azeotropic system, especially the separation of BDO and DMS.

[0172] Table 3-2

[0173]

[0174] Note: a It should be noted that, Figure 3 No second side outlet is added to the top separation zone. The top separation zone is not actually divided into Section I and Section II. The "number of trays in Section I + Section II" in the table is the number of trays in the top separation zone.

[0175] Compared to Example 3: Since the 1,4-butanediol composition to be purified does not contain n-butanol, the theoretical plate number in the top separation zone (Section I + Section II) is significantly reduced, while the top operating temperature is significantly increased. Because the azeotropic (DMS + GBL) stream is not drawn from the side stream, the reflux / BDO output ratio is reduced to some extent.

[0176] Comparative Example 1

[0177] A method for purifying a 1,4-butanediol composition is as follows:

[0178] Taking an annual production capacity of 30,000 tons of BDO as an example, the composition of the 1,4-butanediol composition to be purified is the same as in Example 1 (feed 1).

[0179] like Figure 4 As shown, this comparative example uses a dual-tower process. The 1,4-butanediol composition stream to be purified is introduced into the GBL tower (hereinafter referred to as the left tower) through the feed inlet. The top stream containing n-butanol is collected from the top of the left tower, the azeotropic stream (DMS+GBL) is collected from the top outlet of the left tower, and the bottom stream containing BDO is collected from the bottom of the left tower as the feed to the BDO tower (hereinafter referred to as the right tower). The top stream of the right tower is collected from the light component stream, the purified 1,4-butanediol composition stream is collected from the top outlet of the right tower, and the bottom stream of the heavy component residue is collected from the bottom of the right tower.

[0180] Specifically, the left column has a diameter of 1300 mm and 54 theoretical plates. The feed is located on the 19th theoretical plate (counting from the top of the column, from top to bottom). The absolute pressure at the top of the column is 10 kPaA, the operating temperature at the top of the column is 100℃, and the operating temperature at the bottom of the column is 170℃. The ratio of the mass flow rate of the reflux (top stream 1) to the mass flow rate of the side stream (reflux / side stream) is 5.52. The top stream containing n-butanol is collected from the top of the column, and the bottom stream containing BDO is collected from the bottom of the column (as the feed to the right column). The azeotropic stream (DMS+GBL) is collected from the 13th theoretical plate (counting from the top of the column, from top to bottom).

[0181] The right column has a diameter of 1400 mm and 25 theoretical plates. The feed is located on the 14th theoretical plate (counting from the top of the column, from top to bottom). The absolute pressure at the top of the column is 10 kPaA, the operating temperature at the top of the column is 160℃, and the operating temperature at the bottom of the column is 175℃. The ratio of the mass flow rate of the reflux (top stream 2) to the mass flow rate of the side stream (reflux / side stream) is 2.27. The light component stream is collected from the top of the column, and the heavy component residue stream is collected from the bottom of the column. The purified 1,4-butanediol composition stream is collected from the 8th theoretical plate (counting from the top of the column, from top to bottom).

[0182] Table 4 shows a comparison of the main tower design parameters, tower operating parameters, and tower separation results between Example 1 and Comparative Example 1.

[0183] Table 4

[0184]

[0185] Comparative Example 2

[0186] The difference from Comparative Example 1 is that the composition of the 1,4-butanediol composition stream to be purified is the same as that in Example 2 (feed 2), and the corresponding process conditions are obtained according to the changes in the composition to be purified.

[0187] Table 5 shows a comparison of the main tower design parameters, tower operating parameters, and tower separation results between Example 2 and Comparative Example 2.

[0188] Table 5

[0189]

[0190] Comparative Example 3

[0191] The difference from Comparative Example 1 is that the composition of the 1,4-butanediol composition stream to be purified is the same as that in Example 3 (feed 3), and the corresponding process conditions are obtained according to the changes in the composition to be purified.

[0192] Table 6 shows a comparison of the main tower design parameters, tower operating parameters, and tower separation results between Example 3 and Comparative Example 3.

[0193] Table 6

[0194]

[0195] Variable costs mainly include steam consumption, as well as circulating water and electricity consumption; fixed costs mainly include towers and packing, heat exchangers, pumps, tanks, instruments, pipelines and related buildings and structures, as well as related construction and installation costs.

[0196] This invention uses a partitioned tower and selects appropriate process parameters according to the feeding conditions. This not only significantly reduces variable costs and achieves energy conservation and emission reduction, but also reduces fixed costs and decreases investment in the tower and its ancillary facilities.

[0197] The above data uses an annual production capacity of 30,000 tons of BDO as an example. Currently, the maximum capacity of a single unit using similar technology is approximately 300,000 tons, meaning the benefits of the upgrade will be increased tenfold. Therefore, this invention demonstrates significant economic efficiency and has enormous market potential.

[0198] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for preparing a purified 1,4-butanediol composition, characterized in that, It includes the following steps: Provide the adjacent tower; The 1,4-butanediol composition to be purified is passed into the partition wall column, and the purified 1,4-butanediol composition is obtained by passing it through the partition wall column. The 1,4-butanediol composition to be purified includes γ-butyrolactone, dimethyl succinate, and 1,4-butanediol.

2. The method for preparing a purified 1,4-butanediol composition according to claim 1, characterized in that, The partition tower includes a top separation zone, a partition zone, and a bottom separation zone from top to bottom. The partition zone is divided into a first separation zone and a second separation zone by a partition. The first separation zone is provided with a feed inlet, and the second separation zone is provided with a first side outlet. The purified 1,4-butanediol composition is collected from the first side outlet.

3. The method for preparing a purified 1,4-butanediol composition according to claim 2, characterized in that, It meets one or more of the following conditions: (1) The total theoretical number of trays in the adjacent tower is 32-160; (2) The theoretical number of plates in the first separation zone is 5-40; (3) The theoretical number of plates in the second separation zone is 5-40; (4) The feed inlet is located at the 5th to 25th theoretical tray from top to bottom in the first separation zone; (5) The first side line outlet is located at the 5th to 25th theoretical tray from top to bottom in the second separation zone; (6) The theoretical number of plates in the top separation zone is 5-50; (7) The theoretical number of plates in the bottom separation zone is 5-30.

4. The method for preparing a purified 1,4-butanediol composition according to claim 3, characterized in that, The first separation zone has 10-40 theoretical plates, the second separation zone has 10-40 theoretical plates, the top separation zone has 12-35 theoretical plates, and the bottom separation zone has 8-20 theoretical plates.

5. The method for preparing a purified 1,4-butanediol composition according to any one of claims 2-4, characterized in that, When the 1,4-butanediol composition to be purified also includes n-butanol, the top separation zone is further provided with a second side stream outlet; the n-butanol composition is collected from the top of the partition column, and the azeotrope is collected from the second side stream outlet, the azeotrope including dimethyl succinate and γ-butyrolactone; the second side stream outlet is located at the 2nd to 20th theoretical plate from top to bottom in the top separation zone; Alternatively, if the 1,4-butanediol composition to be purified does not include n-butanol, the azeotrope is collected from the top of the partition column; the azeotrope includes dimethyl succinate and γ-butyrolactone.

6. The method for preparing a purified 1,4-butanediol composition according to any one of claims 2-4, characterized in that, It meets one or two of the following conditions: (1) The position of the partition plate satisfies h / D=0.15-0.7, where h is the maximum width of the first separation zone in the horizontal direction and D is the inner diameter of the partition tower; (2) The distribution ratio R of the partition L The value is between 0.01 and 0.4, where R L The ratio of the amount allocated to the first separation zone to the amount extracted from the top separation zone, wherein the amount extracted from the top separation zone is the total mass flow rate of the descending liquid extracted from the top separation zone; and the amount allocated to the first separation zone is the mass flow rate of the descending liquid extracted from the top separation zone allocated to the first separation zone.

7. The method for preparing a purified 1,4-butanediol composition according to any one of claims 1-4, characterized in that, It meets one or more of the following conditions: (1) The reflux flow rate / BDO output rate is 1-5; wherein, the reflux flow rate / BDO output rate refers to the ratio of reflux flow rate to BDO output rate, the reflux flow rate is the top reflux mass flow rate of the adjacent column, and the BDO output rate is the mass flow rate of the purified 1,4-butanediol composition. (2) The operating temperature at the top of the adjacent tower is 100-170℃; (3) The absolute operating pressure of the partition tower is 5-50 kPaA; (4) The operating temperature of the bottom of the partition tower is 130-200℃.

8. The method for preparing a purified 1,4-butanediol composition according to any one of claims 1-4, characterized in that, It meets one or more of the following conditions: (1) The 1,4-butanediol composition to be purified is a reaction product of the ester hydrogenation process for producing 1,4-butanediol; (2) In the 1,4-butanediol composition to be purified, the mass percentage of γ-butyrolactone is 5%-30%; (3) In the 1,4-butanediol composition to be purified, the mass percentage of dimethyl succinate is 0.1%-15%; (4) In the 1,4-butanediol composition to be purified, the mass percentage of 1,4-butanediol is 55%-95%; (5) In the 1,4-butanediol composition to be purified, the mass percentage of n-butanol is 0-10%.

9. An apparatus for preparing purified 1,4-butanediol compositions, characterized in that, It includes a partition tower, which from top to bottom includes a top separation zone, a partition zone and a bottom separation zone, and the partition zone is divided into a first separation zone and a second separation zone by a partition. The first separation zone is provided with a feed inlet for introducing the 1,4-butanediol composition to be purified; the 1,4-butanediol composition to be purified includes γ-butyrolactone, dimethyl succinate and 1,4-butanediol; The second separation zone is provided with a first side outlet for collecting the purified 1,4-butanediol composition.

10. The apparatus for preparing a purified 1,4-butanediol composition according to claim 9, characterized in that, When the 1,4-butanediol composition to be purified also includes n-butanol, the top separation zone is further provided with a second side outlet for collecting azeotropic substances, which include dimethyl succinate and γ-butyrolactone.

11. The apparatus for preparing a purified 1,4-butanediol composition according to claim 10, characterized in that, The second side outlet is located at the 2nd to 20th theoretical plate from top to bottom in the top separation zone.

12. The apparatus for preparing a purified 1,4-butanediol composition according to any one of claims 9-11, characterized in that, It meets one or more of the following conditions: (1) The total theoretical number of trays in the adjacent tower is 32-160; (2) The theoretical number of plates in the first separation zone is 10-40; (3) The theoretical number of plates in the second separation zone is 10-40; (4) The feed inlet is located at the 5th to 25th theoretical tray from top to bottom in the first separation zone; (5) The first side line outlet is located at the 5th to 25th theoretical tray from top to bottom in the second separation zone; (6) The theoretical number of plates in the top separation zone is 5-50; (7) The theoretical number of plates in the bottom separation zone is 5-30; (8) The position of the partition plate satisfies h / D=0.15-0.7, where h is the maximum width of the first separation zone in the horizontal direction and D is the inner diameter of the partition tower.

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