Equipment for improving stability and purity of rectified product of propylene carbonate device

Abstract

The utility model provides equipment for improving the stability and purity of a rectified product of a propylene carbonate device, which relates to the technical field of propylene carbonate rectification and comprises a rear dehydrogenation tower, a front dehydrogenation tower, a heavy component removal tower and a synchronous treatment device, a water inlet pipe is fixedly connected to the inner top ends of the rear dehydrogenation tower and the front dehydrogenation tower, a water distribution disc is fixedly connected to the output end of the water inlet pipe, and a gas guide pipe is fixedly connected to the interior of the front dehydrogenation tower; by adopting the design, the gas-liquid contact area is increased and the light component removal rate is improved by combining the silk screen structured packing with the shower effect. Secondly, switching between series connection and parallel connection is achieved through the switching valve, and therefore different production requirements are met. And the heat return pipe recovers waste heat at the top of the tower, so that the steam consumption of the de-heavy tower is reduced, and backmixing pollution to products is avoided due to filler optimization and pressure control of the de-heavy tower.

Description

Technical Field

[0001] This utility model relates to the field of propylene carbonate distillation technology, and in particular to a device for improving the stability and purity of propylene carbonate distillation products. Background Technology

[0002] Propylene carbonate is a key solvent in lithium battery electrolytes, polymer materials and gas separation. Traditional propylene carbonate distillation equipment usually adopts a single-tower or double-tower continuous distillation process, including components such as tower body, tower tray, reboiler and condenser.

[0003] The raw material is fed from the middle of the tower. The light components are condensed by the top condenser and part of them are refluxed and part of them are collected as the top of the tower. The heavy components are heated by the bottom reboiler and part of them are vaporized and part of them are discharged as bottom residue. The target product is collected from the side stream or a specific position at the bottom of the tower.

[0004] However, in practical applications, some propylene carbonate distillation units use a single column, which requires a significant increase in the reflux ratio when performing high-purity separation, resulting in a decrease in throughput. At the same time, when pursuing high output, it is difficult to guarantee product purity, making it impossible to flexibly meet the dual requirements of output and purity in different production scenarios.

[0005] Therefore, this utility model provides a device for improving the stability and purity of distillation products from propylene carbonate equipment. Utility Model Content

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a device to improve the stability and purity of the distillation products of propylene carbonate plants.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a device for improving the stability and purity of distillation products from a propylene carbonate unit, comprising a post-dehydrogenation tower, a pre-dehydrogenation tower, and a de-heavyness tower, and further comprising a synchronous processing device, wherein the synchronous processing device comprises wire mesh structured packing fixedly connected inside the post-dehydrogenation tower and the pre-dehydrogenation tower, wherein a water inlet pipe is fixedly connected to the top of the interior of the post-dehydrogenation tower and the pre-dehydrogenation tower, and a water distribution plate is fixedly connected to the output end of the water inlet pipe; wherein a gas guide pipe is fixedly connected inside the pre-dehydrogenation tower, and a switch valve is fixedly connected to the top of the gas guide pipe;

[0008] A multi-stage condensation assembly includes a primary condenser and a secondary condenser fixedly connected inside the front dehydrogenation tower, and a tertiary condenser fixedly connected to the top of the interior of the rear dehydrogenation tower.

[0009] In a preferred embodiment, the top of the switching valve is fixedly connected to the bottom of the post-dehydrogenation tower.

[0010] In a preferred embodiment, the outer side of the water distribution plate is fixedly connected to the inner walls of the rear dehydrogenation tower and the front dehydrogenation tower.

[0011] In a preferred embodiment, both the rear dehydrogenation tower and the front dehydrogenation tower are fixedly connected to a heat reflux pipe on their outer sides, and the other end of the heat reflux pipe is fixedly connected to the de-weighting tower.

[0012] In a preferred embodiment, both the rear dehydrogenation tower and the front dehydrogenation tower are fixedly connected to the outer side with mounting rings.

[0013] In a preferred embodiment, both the bottom outer sides of the post-dehydrogenation tower and the front dehydrogenation tower are fixedly connected to an inlet pipe, and both the top outer sides of the post-dehydrogenation tower and the front dehydrogenation tower are fixedly connected to an outlet pipe.

[0014] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0015] In this invention, the raw gas enters the bottom of the post-dehydrogenation tower and the pre-dehydrogenation tower through the inlet pipe. During its ascent, the honeycomb structure of the wire mesh-structured packing increases the gas-liquid contact area, initially separating light components. At the top of the tower, a water distribution plate sprays liquid evenly through the inlet pipe, creating a showering effect to enhance gas-liquid mass transfer. The series and parallel operation modes can be switched via the linkage of the gas guide pipe and the switching valve. The heat reflux pipes at the top of the post-dehydrogenation tower and the pre-dehydrogenation tower transport high-temperature steam to the heavy component removal tower to preheat the feed liquid. The heavy component removal tower separates heavy component impurities through optimized packing and pressure control. This design, combining the wire mesh-structured packing with the showering effect, increases the gas-liquid contact area and improves the removal rate of light components. Furthermore, the switching valves allow for switching between series and parallel operation to adapt to different production needs. The heat reflux pipe recovers waste heat from the top of the tower, reducing steam consumption in the heavy component removal tower. Additionally, the optimized packing and pressure control in the heavy component removal tower prevent backmixing and product contamination. Attached Figure Description

[0016] Figure 1 A perspective view of an apparatus for improving the stability and purity of distillation products from a propylene carbonate unit, provided by this utility model;

[0017] Figure 2 A schematic diagram of the synchronous processing device structure for improving the stability and purity of distillation products from a propylene carbonate unit, provided by this utility model;

[0018] Figure 3 A schematic diagram of a multi-stage condenser assembly structure for improving the stability and purity of distillation products from a propylene carbonate unit, provided by this utility model;

[0019] Figure 4 This utility model provides a schematic diagram of the post-dehydrogenation tower structure for an apparatus that improves the stability and purity of distillation products from a propylene carbonate unit.

[0020] Legend:

[0021] 1. Post-dehydrogenation tower; 2. Pre-dehydrogenation tower; 3. Heavy removal tower;

[0022] 4. Synchronous processing device; 41. Wire mesh structured packing; 42. Water inlet pipe; 43. Water distribution plate; 44. Air guide pipe; 45. Switch valve;

[0023] 5. Multi-stage condensing assembly; 51. First-stage condenser; 52. Second-stage condenser; 53. Third-stage condenser;

[0024] 6. Heat return pipe; 7. Mounting ring; 8. Air inlet pipe; 9. Air outlet pipe. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] like Figure 1 - Figure 4 As shown, this embodiment provides a technical solution: an apparatus for improving the stability and purity of distillation products from a propylene carbonate unit, comprising a post-dehydrogenation tower 1, a pre-dehydrogenation tower 2, and a de-heavyness tower 3, and a synchronous processing device 4. The synchronous processing device 4 includes a wire mesh structured packing 41 fixedly connected inside the post-dehydrogenation tower 1 and the pre-dehydrogenation tower 2. A water inlet pipe 42 is fixedly connected to the top of the interior of the post-dehydrogenation tower 1 and the pre-dehydrogenation tower 2. A water distribution plate 43 is fixedly connected to the output end of the water inlet pipe 42. The outer side of the water distribution plate 43 is fixedly connected to the inner wall of the post-dehydrogenation tower 1 and the pre-dehydrogenation tower 2. A gas guide pipe 44 is fixedly connected inside the pre-dehydrogenation tower 2. A switch valve 45 is fixedly connected to the top of the gas guide pipe 44. The top of the switch valve 45 is fixedly connected to the bottom of the post-dehydrogenation tower 1.

[0027] The post-dehydrogenation tower 1 initially removes most of the light components from the raw material, while the pre-dehydrogenation tower 2 deeply removes the remaining trace light components. The two towers are connected by a gas guide pipe 44 and a switching valve 45, allowing for flexible switching between series or parallel modes. The heavy component removal tower 3 is specifically designed to process the heavy components in the materials produced by the first two towers, preventing backmixing of impurities. The wire mesh packing 41 is installed inside the two towers, increasing the gas-liquid contact area through its honeycomb structure. The water inlet pipe 42 and the water distribution plate 43 act as a uniform showering assembly at the top of the towers. The water inlet pipe 42 delivers liquid to the water distribution plate 43, while the water distribution plate 43 sprays liquid evenly onto the packing surface through small holes, resulting in uniform liquid distribution and preventing local dry areas or flooding, thus ensuring stable separation efficiency. The gas guide pipe 44 and the switching valve 45 control the gas flow direction between the two towers. In the series mode, the gas guide pipe 44 is open, and the gas flows from the post-dehydrogenation tower 1 to the pre-dehydrogenation tower 2 for secondary treatment. In the parallel mode, the gas guide pipe 44 is closed, and the two towers have independent gas intake. The mode switching is flexible and requires no manual intervention.

[0028] like Figure 2 - Figure 4 As shown, the multi-stage condensing assembly 5 includes a primary condenser 51 and a secondary condenser 52 fixedly connected inside the pre-dehydrogenation tower 2, and a tertiary condenser 53 fixedly connected to the top of the interior of the post-dehydrogenation tower 1. The primary condenser 51 is installed inside the pre-dehydrogenation tower 2, which is equivalent to the first stage of freezing, using hot water at about 80°C to cool the gas at the top of the pre-dehydrogenation tower 2 and condense and recover most of the light components. The secondary condenser 52 is installed inside the pre-dehydrogenation tower 2, which is equivalent to the second stage of freezing, using low-temperature circulating water at about 40°C to further condense the remaining light components. The tertiary condenser 53 is installed at the top of the interior of the post-dehydrogenation tower 1, which is equivalent to the final stage of freezing, using chilled water below 20°C for deep condensation and complete removal of the last light components.

[0029] like Figure 1 As shown, heat reflux pipes 6 are fixedly connected to the outer sides of both the rear dehydrogenation tower 1 and the front dehydrogenation tower 2, and the other end of the heat reflux pipe 6 is fixedly connected to the heavy removal tower 3. Mounting rings 7 are fixedly connected to the outer sides of both the rear dehydrogenation tower 1 and the front dehydrogenation tower 2. Inlet pipes 8 are fixedly connected to the bottom outer sides of both the rear dehydrogenation tower 1 and the front dehydrogenation tower 2, and outlet pipes 9 are fixedly connected to the top outer sides of both the rear dehydrogenation tower 1 and the front dehydrogenation tower 2.

[0030] The heat reflux pipe 6 transports the high-temperature steam discharged from the top of the post-dehydrogenation tower 1 and the pre-dehydrogenation tower 2 to the de-weighting tower 3 through a pipeline to preheat the feed liquid of the de-weighting tower 3. The mounting ring 7 is used to fix the tower body and connect it to the external support or platform. The gas inlet pipe 8 inputs the raw material gas into the tower from the bottom of the tower. The gas outlet pipe 9 discharges the gas treated at the top of the tower to the next stage.

[0031] like Figure 1 - Figure 4 As shown:

[0032] In use: First, the raw material gas enters the tower from the bottom of the post-dehydrogenation tower 1 and the pre-dehydrogenation tower 2 through the gas inlet pipe 8. During the upward process in the tower, the wire mesh structured packing 41 increases the gas-liquid contact area through the honeycomb structure, initially separating the light components. Then, it drives the water distribution plate 43 at the top of the tower to spray liquid evenly through the water inlet pipe 42, forming a shower effect, so that the liquid and gas can fully contact each other.

[0033] Subsequently, after preliminary treatment, the gas is controlled by the linkage between the gas guide pipe 44 and the switching valve 45.

[0034] In the series mode, when the switching valve 45 is opened, the gas flows from the post-dehydrogenation tower 1 to the pre-dehydrogenation tower 2 for secondary distillation, which can drive the multi-stage condensation components 5 for staged processing. The first-stage condenser 51 and the second-stage condenser 52 in the pre-dehydrogenation tower 2 condense the light components step by step, and the third-stage condenser 53 at the top of the post-dehydrogenation tower 1 further freezes them, thereby increasing the removal rate of light components and keeping the product purity stable.

[0035] In the parallel mode, with valve 45 closed, the two towers independently receive gas and process raw materials simultaneously, which can increase the production capacity by 100% to meet the needs of mass production. At the same time, the heat reflux pipe 6 at the top of the post-dehydrogenation tower 1 and the pre-dehydrogenation tower 2 transports high-temperature steam to the de-heavy component tower 3 to preheat its feed liquid, thereby reducing steam consumption. The de-heavy component tower 3 thoroughly separates heavy component impurities through its own packing optimization and pressure control to avoid backmixing. Finally, the purified gas is discharged through the gas outlet pipe 9.

[0036] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. An apparatus for improving the stability and purity of distillation products from a propylene carbonate unit, comprising a post-dehydrogenation tower (1), a pre-dehydrogenation tower (2), and a heavy-weight removal tower (3), characterized in that, It also includes a synchronous processing device (4), which includes wire mesh structured packing (41) fixedly connected inside the post dehydrogenation tower (1) and the front dehydrogenation tower (2). The top of the interior of the post dehydrogenation tower (1) and the front dehydrogenation tower (2) is fixedly connected to a water inlet pipe (42). The output end of the water inlet pipe (42) is fixedly connected to a water distribution plate (43). The interior of the front dehydrogenation tower (2) is fixedly connected to a gas guide pipe (44). The top of the gas guide pipe (44) is fixedly connected to a switch valve (45). The multi-stage condensation assembly (5) includes a first-stage condenser (51) and a second-stage condenser (52) fixedly connected inside the front dehydrogenation tower (2), and a third-stage condenser (53) fixedly connected to the top of the interior of the rear dehydrogenation tower (1).

2. The equipment for improving the stability and purity of distillation products from a propylene carbonate unit according to claim 1, characterized in that: The top of the switching valve (45) is fixedly connected to the bottom of the post-dehydrogenation tower (1).

3. The equipment for improving the stability and purity of distillation products from a propylene carbonate unit according to claim 1, characterized in that: The outer side of the water distribution plate (43) is fixedly connected to the inner wall of the rear dehydrogenation tower (1) and the front dehydrogenation tower (2).

4. The equipment for improving the stability and purity of distillation products from a propylene carbonate unit according to claim 1, characterized in that: The outer sides of both the post-dehydrogenation tower (1) and the front dehydrogenation tower (2) are fixedly connected to heat reflux pipes (6), and the other end of the heat reflux pipes (6) is fixedly connected to the de-weighting tower (3).

5. The equipment for improving the stability and purity of distillation products from a propylene carbonate unit according to claim 1, characterized in that: The outer sides of both the post-dehydrogenation tower (1) and the front dehydrogenation tower (2) are fixedly connected with mounting rings (7).

6. The equipment for improving the stability and purity of distillation products from a propylene carbonate unit according to claim 1, characterized in that: The bottom outer sides of the rear dehydrogenation tower (1) and the front dehydrogenation tower (2) are both fixedly connected with inlet pipes (8), and the top outer sides of the rear dehydrogenation tower (1) and the front dehydrogenation tower (2) are both fixedly connected with outlet pipes (9).

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