Dual column rectification system for reducing single column height

Abstract

This invention discloses a dual-tower distillation system for reducing the height of a single tower, belonging to the technical field of dual-tower distillation systems. It solves the shortcomings of existing single-tower systems, which suffer from excessive height and high operational difficulty and risk for operators. Its main structure includes a main tower and a secondary tower. A feed pipe is installed on the side of the main tower, and the top of the main tower is connected back to the main tower via a reflux tank. The bottom of the main tower is connected to the interior of the secondary tower via the main tower's discharge pipe. The top of the secondary tower is connected to the interior of the main tower via a steam return pipe, and the bottom of the secondary tower is connected back to the interior of the secondary tower via the secondary tower's discharge pipe and a reboiler. This invention is mainly used for separating alcohols with similar boiling points.

Description

Technical Field

[0001] This utility model belongs to the technical field of dual-tower distillation systems, and more specifically, it relates to a dual-tower distillation system for reducing the height of a single tower. Background Technology

[0002] In fields such as chemical production, distillation is often required to separate substances with different boiling points. However, traditional single-tower distillation faces the problem of excessive tower height when handling certain large-scale production or specific process requirements. On the one hand, excessive tower height leads to a significant increase in construction costs. For example, the construction of a tall tower requires a large amount of building materials such as steel, and also places higher demands on construction technology and equipment, increasing investment costs. On the other hand, excessive tower height also brings many difficulties to operation and maintenance. For instance, during equipment installation, inspection, and routine maintenance, a higher working platform and more complex operating equipment are required, increasing the difficulty of the operator's work and safety risks. At the same time, tall towers have more stringent requirements for the foundation, which may require special foundation treatment, further increasing the complexity and cost of the project.

[0003] For example, Chinese invention patent application publication number CN 112891977 A discloses a CHPPO dual-tower distillation separation system and method. It introduces water into a water washer to control the top feed of the distillation tower to be water-free, while the bottom feed of the recovery tower contains water. Through an oil-water separation tank between the distillation tower and the recovery tower, the oil phase in the top feed of the recovery tower is sent back to the distillation tower, and the water phase is returned to the recovery tower. However, its shortcomings are: 1) it cannot be used to separate alcohols with similar boiling points, and 2) it lacks a steam recycling mechanism between the main and auxiliary towers, resulting in poor heat integration. Utility Model Content

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and to provide a dual-tower distillation system for reducing the height of a single tower.

[0005] To achieve the above objectives, this utility model employs the following technical solution:

[0006] A dual-tower distillation system for reducing the height of a single tower includes a main tower and a secondary tower. The main tower has a feed pipe on its side, and its top is connected back to the interior of the main tower via a reflux tank. Its bottom is connected to the interior of the secondary tower via a main tower discharge pipe. The top of the secondary tower is connected to the interior of the main tower via a steam return pipe, and its bottom is connected back to the interior of the secondary tower via a secondary tower discharge pipe and a reboiler.

[0007] Preferably, a condenser for cooling steam is provided between the top of the main tower and the inlet of the reflux tank, and a reflux pump for extracting cooling liquid is provided between the outlet of the reflux tank and the main tower.

[0008] Preferably, a discharge pump is installed on the discharge pipe of the main tower.

[0009] Preferably, the reboiler is further provided with a steam inlet pipe and a cold liquid outlet pipe.

[0010] Preferably, the reflux tank is also provided with a product discharge pipe.

[0011] Preferably, temperature sensors for real-time monitoring of the internal temperature of the main tower are installed at the top, middle and bottom of the main tower.

[0012] Preferably, temperature sensors for real-time monitoring of the internal temperature of the secondary tower are provided at the top, middle and bottom of the tower.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1. By setting up a main tower and a secondary tower and establishing a material and steam circulation channel between them, the distillation process is segmented, effectively reducing the height of a single distillation tower. At the same time, the two towers can be arranged more flexibly according to site conditions to adapt to different production site environments.

[0015] 2. A condenser and reflux tank are installed at the top of the main tower, and the condensate is returned to the inside of the main tower by a reflux pump. This helps to control the temperature at the top of the tower, adjust the reflux ratio, and improve the separation efficiency. At the same time, a discharge pump is installed on the discharge pipe of the main tower, which can improve the stability and controllability of material conveying and ensure the continuous operation of the system.

[0016] 3. Compared to ultra-high single towers, dual towers are easier to operate, and operators can more easily reach various operating points to perform monitoring, adjustment and maintenance work, reducing operational risks and labor intensity;

[0017] 4. The lower height of the two towers makes equipment maintenance and repair more convenient;

[0018] 5. The dual towers can be optimized for different separation stages. For example, the main tower can focus on preliminary separation, while the secondary tower can perform fine separation, thereby improving the overall separation effect and product quality.

[0019] 6. The dual-tower system can better realize the recovery and utilization of heat energy, and can transfer the waste heat of one tower to another tower, thereby improving energy utilization efficiency and reducing energy consumption;

[0020] In summary, this invention utilizes a dual-tower distillation system to reduce the height of a single tower. By distributing the task of what would have been a single tall tower to two relatively shorter towers, it effectively reduces construction costs, simplifies operation and maintenance, and improves the reliability and economy of the entire production system without affecting the distillation effect. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the system of this utility model.

[0022] In the diagram: 1. Reflux tank; 2. Main tower; 3. Steam return pipe; 4. Secondary tower; 5. Reboiler; 6. Cold liquid outlet pipe; 7. Steam inlet pipe; 8. Main tower discharge pipe; 9. Condenser; 10. Reflux pump; 11. Discharge pump; 12. Feed pipe; 13. Secondary tower discharge pipe; 14. Product discharge pipe. Detailed Implementation

[0023] The present invention will be further described below through specific embodiments and in conjunction with the accompanying drawings.

[0024] Example 1:

[0025] like Figure 1 As shown, a dual-tower distillation system for reducing the height of a single tower includes a main tower 2 and a secondary tower 4. The main tower 2 has a feed pipe 12 on its side. The top of the tower is connected back to the interior of the main tower 2 through a reflux tank 1, and the bottom of the tower is connected to the interior of the secondary tower 4 through a main tower discharge pipe 8. A discharge pump 11 is installed on the main tower discharge pipe 8. The top of the secondary tower 4 is connected to the interior of the main tower 2 through a steam return pipe 3, and the bottom of the secondary tower 4 is connected back to the interior of the secondary tower 4 through a secondary tower discharge pipe 13 and a reboiler 5.

[0026] In actual production processes, since the boiling points of various components are relatively similar, separating them requires increasing the height of the distillation column to expand the temperature range. However, excessively increasing the height of a single column is not only costly but also difficult to operate. Therefore, this invention achieves segmented processing of the distillation process by setting up a main column 2 and a secondary column 4, and establishing a material and steam circulation channel between them. This effectively reduces the height of a single distillation column, not only solving the goal of separating components with similar boiling points but also reducing costs and improving safety.

[0027] In this embodiment, in the main column 2, the mixture is separated according to the differences in boiling points of each component. The auxiliary column 4 provides heat to partially vaporize the liquid at the bottom of the column. The rising vapor and the descending liquid undergo mass and heat transfer on the trays or packing. The more volatile components are enriched in the vapor and gradually rise to the top of the column. The vapor at the top of the column enters the condenser 9 and is cooled into liquid, flowing into the reflux tank 1. Part of it is pumped back into the main column 2 by the reflux pump 10. The reflux tank 1 is also equipped with a product discharge pipe 14, through which qualified products are collected.

[0028] Example 2:

[0029] A dual-tower distillation system for reducing the height of a single tower differs from Embodiment 1 in that a condenser 9 for cooling vapor is provided between the top of the main tower 2 and the feed inlet of the reflux tank 1, and a reflux pump 10 for drawing cooling liquid is also provided between the discharge outlet of the reflux tank 1 and the main tower 2.

[0030] Furthermore, temperature sensors for real-time monitoring of the internal temperature of the main tower 2 are installed at the top, middle and bottom of the main tower 2, and temperature sensors for real-time monitoring of the internal temperature of the secondary tower 4 are installed at the top, middle and bottom of the secondary tower 4. Temperature changes are monitored in real time through temperature sensors and adjustments are made as needed.

[0031] This invention controls the temperature distribution of various parts of the main column 2 and the auxiliary column 4 by adjusting the heating power of the reboiler 5 and the cooling water volume of the condenser 9. The temperature at different locations reflects the concentration changes of different components and is an important indicator for judging whether the distillation process is proceeding normally.

[0032] Maintaining appropriate pressure within the column is crucial for the stable operation of the distillation process; excessively high or low pressure will affect the gas-liquid balance and separation efficiency. The pressure within the column can be controlled by adjusting the cooling water flow rate of condenser 9, the venting rate of reflux tank 1, or by using pressure control valves.

[0033] The reflux ratio can be controlled by adjusting the liquid level in the reflux tank 1 and the flow rate of the reflux pump 10. The appropriate reflux ratio needs to be selected by comprehensively considering factors such as feed composition, product quality requirements, and energy consumption.

[0034] The liquid levels at the bottom of the main tower 2 and the auxiliary tower 4, as well as the liquid level in the reflux tank 1, need to be maintained within an appropriate range. If the liquid level is too high, it may cause the tower to flood, affecting gas-liquid mass transfer; if the liquid level is too low, it may cause the reboiler 5 to burn dry or the pump to run dry.

[0035] The working principle of this utility model is as follows:

[0036] I. Feeding and Initial Separation (Main Tower 2 Operation):

[0037] The raw material enters the middle of the main tower 2 through the feed pipe 12. In the packing or on the tower plate, the gas and liquid phases come into full contact and carry out mass and heat transfer. Due to the different volatility of each component, the more volatile components gradually accumulate in the steam and reach the top of the tower with the rising steam; while the less volatile components accumulate more in the liquid and flow downward to the bottom of the tower.

[0038] The vapor at the top of the column is cooled by the condenser 9 to form a liquid phase, which flows into the reflux tank 1. Part of the liquid in the reflux tank 1 is returned to the main column as reflux liquid by the reflux pump 10 to maintain the stability of the column top temperature and improve the separation accuracy; the other part is collected as the final product through the product discharge pipe 14.

[0039] The liquid at the bottom of the main tower, containing a large amount of high-boiling-point components, is transported to the auxiliary tower 4 for further processing via the discharge pipe 8 and the discharge pump 11.

[0040] II. Heat Recovery and Secondary Distillation (Operation of Sub-tower 4):

[0041] The liquid discharged from the bottom of the main column 2 mainly contains high-boiling-point components and a small amount of low-boiling-point components. It enters the secondary column 4 for further distillation. The reboiler 5 is also equipped with a steam inlet pipe 7 and a coolant outlet pipe 6. Steam enters through the steam inlet pipe 7, while the cooled liquid is discharged from the reboiler 5 through the coolant outlet pipe 6. At this time, the secondary column 4 enters the reboiler 5 through the secondary column outlet pipe 13 to provide heat, causing the liquid at the bottom of the column to vaporize. The rising steam and the falling liquid undergo mass and heat transfer in the column. The high-boiling-point product or residue discharged from the bottom of the secondary column 4 can be further processed as needed.

[0042] III. Parameter Monitoring and Control:

[0043] To ensure the stable operation of the entire system, temperature sensors are installed at the top and bottom of both the main column 2 and the auxiliary column 4 to monitor the temperature changes of each key part in real time. The temperature data reflects the component concentration distribution and is an important basis for judging the distillation effect.

[0044] Meanwhile, the system controls the operating temperature and pressure of the main tower 2 and the auxiliary tower 4 by adjusting the cooling water volume of the condenser 9, the heating power of the reboiler 5, and the flow rate of the reflux pump 10, thereby maintaining a gas-liquid balance.

[0045] In summary, this invention achieves efficient separation of mixed components with similar boiling points through the synergistic effect of the main column 2 and the auxiliary column 4. It breaks down the multi-component separation task, which originally required extremely tall columns, into a distillation process involving the cooperation of two columns, thereby significantly reducing the height of a single column while maintaining separation efficiency.

Claims

1. A dual-tower distillation system for reducing the height of a single tower, characterized in that: The main tower (2) includes a main tower (2) and a secondary tower (4). The main tower (2) is provided with a feed pipe (12) on its side. The top of the tower is connected back to the interior of the main tower (2) through a reflux tank (1), and the bottom of the tower is connected to the interior of the secondary tower (4) through the main tower discharge pipe (8). The top of the secondary tower (4) is connected to the interior of the main tower (2) through a steam return pipe (3), and the bottom of the secondary tower (4) is connected back to the interior of the secondary tower (4) through the secondary tower discharge pipe (13) and a reboiler (5).

2. The dual-tower distillation system for reducing the height of a single tower according to claim 1, characterized in that: A condenser (9) for cooling steam is provided between the top of the main tower (2) and the inlet of the reflux tank (1), and a reflux pump (10) for drawing cooling liquid is provided between the outlet of the reflux tank (1) and the main tower (2).

3. The dual-tower distillation system for reducing the height of a single tower according to claim 2, characterized in that: A discharge pump (11) is installed on the discharge pipe (8) of the main tower.

4. The dual-tower distillation system for reducing the height of a single tower according to claim 2, characterized in that: The reboiler (5) is also equipped with a steam inlet pipe (7) and a cold liquid outlet pipe (6).

5. The dual-tower distillation system for reducing the height of a single tower according to any one of claims 1-4, characterized in that: The reflux tank (1) is also equipped with a product discharge pipe (14).

6. The dual-tower distillation system for reducing the height of a single tower according to any one of claims 1-4, characterized in that: Temperature sensors for real-time monitoring of the internal temperature of the main tower (2) are installed at the top, middle and bottom of the tower.

7. The dual-tower distillation system for reducing the height of a single tower according to claim 6, characterized in that: Temperature sensors for real-time monitoring of the internal temperature of the secondary tower (4) are installed at the top, middle and bottom of the tower.

Images