Reduced pressure distillation tower structure with forced circulation pump

Abstract

The utility model discloses a reduced pressure distillation tower structure with a forced circulation pump, which relates to the technical field of chemical separation and comprises a distillation tower, a return tank, a circulation pump and a tower kettle pump, the reflux tank is connected with the top of the distillation tower through a pipeline; the inlet end of the circulating pump is connected with the outlet end of the return tank through a pipeline; two pipelines are arranged at the outlet end of the circulating pump, one pipeline is used for extracting mixed alcohol, and the other pipeline is connected with a treatment area at the upper part of the distillation tower; through the design of a double-tower series connection process and the combination of a temperature control system and a vacuum environment, the boiling point of a material is effectively reduced, side reaction is inhibited, an n-isomer volatility difference strengthening technology is adopted, and through molecular polarity regulation and control and tower plate fluid mechanics optimization, the high-purity isomer is obtained. And accurate separation of normal alcohol and isomeric alcohol is realized.

Description

Technical Field

[0001] This utility model relates to the technical field of chemical separation, and more specifically, to a vacuum distillation tower structure with a forced circulation pump. Background Technology

[0002] In the industrial production of higher alcohols, the boiling point difference between normal and isomeric alcohols is small (approximately 10°C), making it difficult for existing distillation techniques to achieve high-purity (≥99.5%) separation. Traditional methods suffer from high energy consumption, low separation efficiency, and poor equipment stability, particularly in vacuum control, reflux ratio adjustment, and the stability of the bottom pump, leading to product quality fluctuations and equipment wear and tear.

[0003] Based on this, the present invention provides a vacuum distillation column structure with a forced circulation pump. Utility Model Content

[0004] To address the problems mentioned in the background art, this utility model provides a vacuum distillation column structure with a forced circulation pump. Through a dual-column series process design, combined with a temperature control system and a vacuum environment, the boiling point of the material is effectively reduced and side reactions are suppressed. By employing the difference in volatility between normal and isomers to enhance the separation of normal and isomer alcohols through molecular polarity regulation and tray fluid dynamics optimization, the precise separation of normal and isomer alcohols is achieved.

[0005] The vacuum distillation column structure with a forced circulation pump provided by this utility model adopts the following technical solution:

[0006] A vacuum distillation column structure with a forced circulation pump includes a distillation column, a reflux tank, a circulation pump, and a bottom pump. The reflux tank is connected to the top of the distillation column via a pipeline. The inlet of the circulation pump is connected to the outlet of the reflux tank via a pipeline. The outlet of the circulation pump is provided with two pipelines: one pipeline for the collection of mixed alcohols, and the other pipeline connected to the upper processing area of ​​the distillation column. The inlet of the bottom pump is connected to the bottom of the distillation column via a pipeline.

[0007] Preferably, a return pipe is provided between the outlet end of the circulating pump and the discharge pipeline of the return tank.

[0008] Preferably, the reflux pipe is equipped with a valve.

[0009] Preferably, a balance pipe is provided at the outlet end of the distillation column pump and at the bottom of the distillation column.

[0010] Preferably, the distillation column includes a column body, a steam inlet tank disposed in the lower region of the column body, and a raw material inlet pipe disposed in the upper region of the column body.

[0011] In summary, this utility model has the following beneficial technical effects:

[0012] 1. By using a dual-tower series process design, combined with a temperature control system and a vacuum environment, the boiling point of the material is effectively reduced and side reactions are suppressed. By adopting the difference in volatility enhancement technology between the positive and negative isomers, and through molecular polarity regulation and tray fluid dynamics optimization, the precise separation of the positive and negative alcohols and the negative alcohols is achieved.

[0013] 2. A return pipe (minimum return flow) is installed between the outlet of the circulating pump and the discharge pipeline of the return tank. A self-regulating valve is configured to automatically open the bypass when the flow rate is lower than MCSF. Multi-stage flow limiting orifice plates are used to control the return flow deviation. A π-type expansion bend is added to the high-temperature pipeline to eliminate thermal stress. This design can ensure that the pump operating flow rate is ≥ MCSF to avoid cavitation, reduce the fluctuation of the main process flow rate, and reduce the overall energy consumption compared with the traditional frequency conversion scheme, thus achieving dual optimization of safety and energy efficiency.

[0014] 3. A balance pipe connected to the gas phase space of the tower bottom is added after the inlet valve of the tower bottom pump. The pressure compensation mechanism enables the pump chamber to be dynamically balanced with the vacuum environment inside the tower, ensuring that the liquid priming conditions are maintained during pump shutdown.

[0015] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the present invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the vacuum distillation tower with a forced circulation pump in an embodiment of this utility model;

[0017] Figure 2 This is a schematic diagram of the vacuum distillation tower structure in an embodiment of this utility model.

[0018] Explanation of reference numerals in the attached drawings: 1. Distillation column; 100. Column body; 101. Steam inlet tank; 102. Raw material inlet pipe; 2. Reflux tank; 3. Circulation pump; 4. Bottom pump; 5. Reflux pipe; 6. Balance pipe. Detailed Implementation

[0019] The following is in conjunction with the appendix Figures 1 to 2 The present invention will be described in further detail below.

[0020] It should be noted that the accompanying drawings are schematic and not to scale. For clarity and convenience, the relative dimensions and proportions of the parts shown are exaggerated or reduced in size; all dimensions are merely illustrative and not limiting. Furthermore, the same reference numerals are used for the same structures, elements, or fittings appearing in more than two drawings to indicate similar features.

[0021] This utility model discloses a vacuum distillation column structure with a forced circulation pump. (Refer to...) Figures 1 to 2 The structure of the vacuum distillation column with a forced circulation pump includes a distillation column 1, a reflux tank 2, a circulation pump 3, and a bottom pump 4.

[0022] The distillation column 1 includes a column body 100, a steam inlet tank 101 located in the lower region of the column body 100, and a raw material inlet pipe 102 located in the upper region of the column body 100. Other specific structures and connections of the distillation column 1 are based on existing technology and are not the focus of this utility model, so they will not be described in detail here.

[0023] Specifically, the reflux tank 2 is connected to the top of the distillation column 1 via a pipeline; the inlet of the circulation pump 3 is connected to the outlet of the reflux tank 2 via a pipeline; the outlet of the circulation pump 3 is equipped with two pipelines, one for the extraction of mixed alcohol and the other for connection to the upper processing area of ​​the distillation column 1; the inlet of the bottom pump 4 is connected to the bottom of the distillation column 1 via a pipeline.

[0024] like Figure 1 As shown, a return pipe 5 is installed between the outlet end of the circulating pump 3 and the discharge pipeline of the return tank 2, and the return pipe 5 is equipped with a valve.

[0025] In the operation of distillation column 1, the reflux ratio needs to be controlled within the range of 1-5 according to the characteristics of the system: for systems with similar boiling points (relative volatility α approaching 1), a high reflux ratio (4-5) is required due to the high separation difficulty to improve the theoretical tray efficiency, while matching the load of the top condenser to balance energy consumption; for systems with significantly different boiling points (α≥2), a low reflux ratio (1-2) can meet the separation requirements, but the risk of entrainment of light components must be prevented. When the system is running at a low reflux ratio, the synchronous decrease in reflux flow and output flow can easily lead to the centrifugal pump outlet flow rate falling below the minimum continuous stable flow rate, causing problems such as cavitation, vibration, and mechanical seal damage. At the same time, the regulating valve enters the nonlinear control region due to excessively small opening, causing flow fluctuations. To address this issue, a reflux pipe 5 (minimum reflux) is installed between the outlet of circulating pump 3 and the discharge pipeline of reflux tank 2, and a self-regulating regulating valve (such as...) is configured. The FCL series automatically opens the bypass when the flow rate is lower than MCSF, supplemented by multi-stage flow-limiting orifice plates to control backflow deviation, and adds π-type expansion bends to high-temperature pipelines to eliminate thermal stress. This design can ensure that the pump operating flow rate is ≥ MCSF to avoid cavitation, reduce the fluctuation of the main process flow rate, and reduce overall energy consumption compared with traditional frequency conversion solutions, achieving dual optimization of safety and energy efficiency.

[0026] like Figure 1 As shown, a balance pipe 6 is installed at the outlet end of the distillation column pump 4 and at the bottom of the distillation column 1.

[0027] During the operation of the distillation system, the stability control of the reboiler pump 4 faces unique challenges: when the production load fluctuates or the output is unstable, frequent start-stop cycles can easily cause process parameters to oscillate. Especially after the pump stops under vacuum conditions, the negative pressure environment inside the column prevents the pump chamber from effectively establishing a priming static pressure head (i.e., "priming" failure). Upon restarting, cavitation can easily occur, leading to uncontrolled liquid level in the reboiler. In view of this, a balance pipe 6 connected to the gas phase space of the reboiler is added after the inlet valve of the reboiler pump 4. Through a pressure compensation mechanism, the pump chamber and the vacuum environment inside the column are dynamically balanced, ensuring that priming conditions are maintained during pump shutdown.

[0028] In the production of higher alcohols, two sets of the structures described in this application are used as follows: Figure 2 As shown, the outlet end of the first set of tower reboiler pump 4 is connected to the raw material inlet pipe 102 of the second set of structures. The specific process is as follows:

[0029] The raw material mixed with higher alcohols first enters the first-structure distillation column 1, where selective volatilization is carried out at 200-230℃ / 8kPa. The light components at the top of the column (containing isomeric alcohols and trace amounts of low carbonic acid) are liquefied by a falling film condenser (45-50℃) and then enter the reflux tank 2. Dynamic reflux ratio management (R=3:1) is implemented by a proportional regulating circulation pump 3 to control the content of n-alcohols in the produced material to be ≤5%.

[0030] The n-alcohol-rich material from the bottom of the column is continuously pumped by the bottom pump 4 to the second-structure distillation column 1. Under enhanced separation conditions of 220-250℃ / 5kPa, the high-purity n-alcohol (≥99.2%) at the top of the column is captured by a two-stage condensation system and enters the reflux tank 2. The reflux ratio of the rectification section is precisely controlled (R=5:1) by the circulation pump 3. An online near-infrared detector is installed at the collection end to ensure product quality. The heavy components at the bottom of the column (polyols and polymerization by-products) are output to the residual liquid treatment system by the bottom pump 4, and the residual effective component content is ≤5%.

[0031] The entire process adopts DCS interlock control, which reduces energy consumption intensity and increases product yield compared with traditional processes.

[0032] This invention utilizes a dual-tower series process design, combined with a temperature control system (operating temperature gradient controlled at 180-280℃) and a vacuum environment (system pressure 5-10kPa), to effectively reduce the boiling point of materials and suppress side reactions. Employing a technology that enhances the difference in volatility between normal and isomers, and through molecular polarity regulation and tray hydrodynamic optimization, it achieves precise separation of normal and isomer alcohols.

[0033] All standard parts used in this utility model can be purchased from the market. Irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment adopt conventional models in the prior art. In addition, the circuit connection adopts conventional connection methods in the prior art, which will not be described in detail here.

[0034] In the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. "A plurality of" means two or more, unless otherwise explicitly specified.

[0035] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0036] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] The accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other.

[0039] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vacuum distillation column structure with a forced circulation pump, characterized in that, include: Distillation column (1), reflux tank (2), circulating pump (3) and bottom pump (4); The reflux tank (2) is connected to the top of the distillation column (1) via a pipeline; The inlet end of the circulating pump (3) is connected to the outlet end of the return tank (2) via a pipeline; The outlet end of the circulating pump (3) is provided with two pipelines, one pipeline for the extraction of mixed alcohol, and the other pipeline connected to the upper processing area of ​​the distillation column (1). The inlet end of the distillation column pump (4) is connected to the bottom of the distillation column (1) via a pipeline.

2. The vacuum distillation column structure with a forced circulation pump according to claim 1, characterized in that: A return pipe (5) is provided between the outlet end of the circulating pump (3) and the discharge pipeline of the return tank (2).

3. The vacuum distillation column structure with a forced circulation pump according to claim 2, characterized in that: The return pipe (5) is equipped with a valve.

4. The vacuum distillation column structure with a forced circulation pump according to claim 1, characterized in that: The outlet end of the distillation column pump (4) is equipped with a balance pipe (6) at the bottom of the distillation column (1).

5. The vacuum distillation column structure with a forced circulation pump according to any one of claims 1-4, characterized in that: The distillation column (1) includes a column body (100), a steam inlet tank (101) located in the lower region of the column body (100), and a raw material inlet pipe (102) located in the upper region of the column body (100).

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