A two-stage high-boiling substance pretreatment device and a system using the same

Abstract

The utility model discloses a high boiling matter two-stage pretreatment device and system using the device, including primary heating kettle, secondary heating groove and the conveying pipeline that links primary heating kettle and secondary heating groove, sets up primary heating jacket outside primary heating kettle, sets up high boiling matter raw material entrance and primary steam export respectively in the upper portion both sides of primary heating kettle, is sealed in the top of primary heating kettle, and sets up agitator shaft motor at its top, sets up conveying valve in the side of conveying pipeline close to primary heating kettle, sets up agitator cage motor in the side of connecting secondary heating groove, sets up secondary heating jacket outside secondary heating groove, sets up solid discharge port in the bottom of secondary heating groove, sets up secondary steam export in the top of secondary heating groove, and the material in secondary heating groove is stirred and pushes to solid discharge port by auxiliary stirring and pushing mechanism. The device can quickly and efficiently steam out high boiling matter and not stick kettle through two-stage heating treatment, and the device structure is simple, and the cost is low.

Description

Technical Field

[0001] This utility model relates to the field of high-boiling-point substance recovery technology, specifically to a two-stage pretreatment device for high-boiling-point substances and a system using the device, which is particularly suitable for pretreatment of high-boiling-point substance mixtures generated during the chlorination process of PVC. Background Technology

[0002] The ethylene chlorination process for PVC production generates a large amount of high-boiling-point substances. This mixture contains a significant amount of valuable 1,2-dichloroethane (boiling point 83.5℃) and other substances. The high-boiling-point substances produced in the ethylene chlorination process differ from those produced in the acetylene process. The high-boiling-point substances from the ethylene chlorination process are primarily composed of 1,2-dichloroethane (the high-boiling-point substances from the calcium carbide process are mainly 1,1-dichloroethane, boiling point 57.3℃), which is quite viscous. Previous treatment processes have been unable to address the recycling of 1,2-dichloroethane, forcing it to be treated as hazardous waste. This results in substantial annual hazardous waste disposal costs for companies.

[0003] Existing pretreatment devices for high-boiling-point substances generally only perform simple evaporation in an evaporator, extracting a small portion of the liquid phase and treating the remaining mixture as waste. This results in low product recovery efficiency. Alternatively, expensive foreign incinerators can be purchased for processing, which typically cost hundreds of millions of yuan. Although the incineration process can recover some heat, the actual incineration cost is also very high, wasting recyclable raw materials and increasing processing costs. Utility Model Content

[0004] To address the shortcomings of existing technologies, the technical problem this invention aims to solve is to provide a two-stage pretreatment device for high-boiling-point substances and a system using this device. This device, through two-stage heating treatment, can rapidly and efficiently distill high-boiling-point substances without sticking to the vessel. The device has a simple structure and low cost.

[0005] The technical solution adopted by this utility model to solve the aforementioned technical problem is as follows: A two-stage pretreatment device for high-boiling-point substances includes a primary heating vessel (3), a secondary heating tank (15), and a conveying pipe (8) connecting the primary heating vessel and the secondary heating tank. A primary heating jacket (2) is provided outside the primary heating vessel (3). A high-boiling-point substance raw material inlet (1) and a primary steam outlet (6) are respectively provided on the upper two sides of the primary heating vessel (3). The top of the primary heating vessel (3) is sealed, and a stirring shaft motor (5) is provided on its top. A stirring shaft (4) is connected below the stirring shaft motor (5) and the stirring shaft (4) extends into the interior of the primary heating vessel (3). The conveying pipe (8) is located at the lower part of the primary heating vessel (3) and connected to the secondary heating tank (15); the conveying pipe (8) is provided with a conveying valve on the side near the primary heating vessel, and a stirring cage motor (10) is provided on the side connected to the secondary heating tank; a stirring cage conveying shaft (9) is provided in the conveying pipe (8), and the stirring cage conveying shaft is connected to the stirring cage motor. A secondary heating jacket (11) is provided outside the secondary heating tank (15), a solid discharge port (14) is provided at the bottom of the secondary heating tank, and a secondary steam outlet (16) is provided at the top of the secondary heating tank. The material in the secondary heating tank (15) is stirred and pushed to the solid discharge port (14) by an auxiliary stirring and pushing mechanism.

[0006] Furthermore, both the primary steam outlet and the secondary steam outlet are connected to the post-treatment equipment for high-boiling-point substances.

[0007] Furthermore, stirring blades are provided on the stirring shaft 4. The stirring blades are arranged in layers along the height direction of the primary heating vessel. During the rotation of the stirring blades, they do not touch the wall of the primary heating vessel, but can stir all the liquid in the primary heating vessel, thus avoiding the formation of dead zones in the liquid stirring.

[0008] Furthermore, the stirring shaft is provided with spiral stirring blades along the height direction. The stirring blades are designed to stir all the liquid in the primary heating vessel without hitting the walls, thus avoiding dead zones in the liquid stirring.

[0009] Furthermore, the primary heating jacket and the secondary heating jacket are heated by circulating steam, hot water or heat transfer oil. The upper end of the primary heating jacket is located below the primary steam outlet, and the upper end of the primary heating jacket is not less than 1 / 4 of the height of the primary heating vessel body. The upper end of the secondary heating jacket is at the same height as the upper end of the secondary heating tank.

[0010] Furthermore, the auxiliary stirring and pushing mechanism includes a crushing and pushing shaft (13) and a crushing and pushing motor (12). The crushing and pushing shaft is located at the lower part of the secondary heating tank (15). The crushing and pushing shaft does not contact the wall of the secondary heating tank. The crushing and pushing shaft is arranged horizontally, and the secondary heating tank is a horizontal tank.

[0011] Furthermore, the conveying pipe (8) is inclinedly arranged at the lower part of the primary heating vessel (3), and the inclination angle of the conveying pipe (8) is 10°-85°; Meters are installed at the secondary steam outlet, primary steam outlet, and conveying pipeline to collect data on the secondary steam output, primary steam output, and material entering the secondary heating tank, respectively. A meter is also installed at the inlet of the high-boiling-point raw material. The conveying valve is normally closed.

[0012] Furthermore, the auxiliary stirring and pushing mechanism includes a scraper and a vertical blade.

[0013] This utility model also protects a high-boiling-point substance recovery system using the aforementioned two-stage pretreatment device, wherein the high-boiling-point substance raw material inlet is connected to a conveying pipeline for the high-boiling-point substance mixture to be recovered, and both the primary steam outlet and the secondary steam outlet are connected to the high-boiling-point substance post-treatment equipment.

[0014] Furthermore, the high-boiling-point mixture is a high-boiling-point mixture produced during the ethylene chlorination process of PVC production, with 1,2-dichloroethane as the main component.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention comprises two parts: a primary heating stage and a secondary heating stage. After treatment in the primary heating tank, a large amount of liquid is rapidly vaporized and extracted from the primary steam outlet, increasing the yield of high-boiling-point substances. The material, after the primary heating tank has removed a significant amount of liquid, is then fed into the secondary heating tank. The steam generated during the secondary heating process is extracted through the secondary steam outlet. An auxiliary stirring and pushing mechanism ensures uniform heating, guaranteeing the long-term operation of the device and system, and solving the problem of material overheating and coking / sticking to the tank during single-stage heating.

[0016] The system using the device described in this utility model solves the problem of frequent blockages and shutdowns caused by directly feeding the high-boiling mixture generated in the ethylene chlorination PVC production into the distillation column in the traditional process. The recovery rate and purity are high, and the pretreatment device ensures that the solid part does not coke, does not stick to the reactor, and is easy to break and handle while maintaining the solid.

[0017] This utility model features low equipment investment, low cost, simple operation, high operational flexibility, and can increase the throughput by at least 40% for the same volume diameter. At the same time, it solves the problems of serious material entrainment, frequent blockage of trays or packing in traditional processes, inability to operate continuously for long periods of time, and difficulty in maintenance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of a two-stage pretreatment device for high-boiling-point substances according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of a two-stage pretreatment device for high-boiling-point substances according to an embodiment of the present invention.

[0020] In the diagram, 1. High-boiling-point raw material inlet; 2. Primary heating jacket; 3. Primary heating vessel; 4. Stirring shaft; 5. Stirring shaft motor; 6. Primary steam outlet; 7. Conveying valve; 8. Conveying pipeline; 9. Stirring cage conveying shaft; 10. Stirring cage motor; 11. Secondary heating jacket; 12. Crushing push motor; 13. Crushing push shaft; 14. Solid discharge port; 15. Secondary heating tank; 16. Secondary steam outlet; 17. Scraper; 18. Vertical blade. Detailed Implementation

[0021] The present invention will be further explained below with reference to the embodiments and accompanying drawings, but this is not intended to limit the scope of protection of this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0022] Example 1 The two-stage pretreatment device for high-boiling-point substances in this embodiment is as follows: Figure 1 As shown, it includes a high-boiling-point raw material inlet (1); a primary heating jacket (2) (with steam or heat transfer oil inside); a primary heating vessel (3); a stirring shaft (4); a stirring shaft motor (5); a primary steam outlet (6); a conveying valve (7); a conveying pipe (8); a stirring cage conveying shaft (9); a stirring cage motor (10); a secondary heating jacket (11) (with steam or heat transfer oil inside); a crushing push motor (12); a crushing push shaft (13); a solid discharge port (14); a secondary heating tank (15); and a secondary steam outlet (16).

[0023] The positions are as follows: a primary heating jacket (2) is provided on the outside of the primary heating vessel (3); the high-boiling-point raw material inlet (1) and the primary steam outlet (6) are both on the upper side of the primary heating vessel (3), but in different orientations. A stirring shaft motor (5) is provided on the top of the primary heating vessel (3), and a stirring shaft (4) is connected below the stirring shaft motor (5), with the stirring shaft (4) extending into the interior of the primary heating vessel (3). The conveying pipe (8) is located at the lower part of the primary heating vessel (3), and the conveying valve (7) is located in the upper part of the conveying pipe (8). The stirring cage conveying shaft (9) is located inside the conveying pipe (8) and below the conveying valve (7), with the stirring cage motor (10) connected behind the stirring cage conveying shaft (9).

[0024] The secondary heating tank (15) is equipped with a secondary heating jacket (11) on the outside and a crushing push shaft (13) inside. The bottom is a solid discharge port (14). When the material is heated in the secondary heating tank (15), the crushing push shaft (13) rotates to crush larger solids into smaller pieces and form a jelly-like solid. After heating, the crushing push shaft (13) sends the jelly-like solid out of the equipment through the solid discharge port (14). The steam generated during the heating process is extracted through the secondary steam outlet (16).

[0025] The crushing push motor (12) and the crushing push shaft (13) constitute the auxiliary stirring and pushing mechanism.

[0026] The pretreatment device divides the entire process into two parts. First, in the primary heating vessel (3), due to the large amount of liquid and the low viscosity of the solid-liquid mixture, a large amount of liquid can be quickly vaporized and sent to the post-treatment device, such as a distillation column. The material after removing a large amount of liquid is sent to the secondary heating tank (15). Then, in the secondary heating tank (15), the material is more viscous. Under the rotational motion of the crushing and pushing shaft (13), the solid-liquid mixture can be transformed into smaller, jelly-like solids suitable for subsequent processing and pushed out during the solidification process.

[0027] This utility model device adopts a horizontal two-stage heating tank with the crushing and pushing shaft arranged at the bottom to avoid coking at the bottom of the heating tank. At the same time, the up-and-down flipping action of the crushing and pushing shaft can make the material coke evenly, eventually forming a jelly-like solid. The formed jelly-like solid is discharged from the solid discharge port. This jelly-like solid has the advantages of elasticity and cohesiveness, easy breakage and non-sticking to the pot, making it easier to push, avoiding the phenomenon of sticking to the wall, and improving heating efficiency.

[0028] Example 2 In this embodiment, the angle between the conveying pipe 8 and the horizontal plane is 10°~90°, and can be any angle such as 10°, 20°, 30°, 50°, 60°, 70°, 85°, 88°, etc., preferably 30-60°.

[0029] Example 3 This embodiment of the high-boiling-point recovery system is used to treat the high-boiling-point mixture generated in the ethylene chlorination process of PVC production. The primary steam outlet 6 and the secondary steam outlet are both connected to the distillation column 102.

[0030] The temperature in the primary heating vessel (3) is 50-120℃, the pressure is 1kPa (absolute pressure) to atmospheric pressure, and the heating time is 2-72 hours after entering the vessel.

[0031] The temperature in the secondary heating bath 15 is 70-150℃, the pressure is 1kPa (absolute pressure) to atmospheric pressure, and the heating time is 12-108 hours after entering the vessel. The preferred temperature is 70-140℃.

[0032] Example 4 The two-stage pretreatment device for high-boiling-point substances in this embodiment is as follows: Figure 2 As shown, stirring blades are provided on the stirring shaft 4, and the stirring blades are arranged in layers along the height direction of the primary heating vessel. The auxiliary stirring and pushing mechanism includes a scraper 17 and a vertical blade 18. The secondary heating tank adopts a vertical structure, and the solid discharge port 14 is located at the bottom of the secondary heating tank. The specific driving operation of the scraper and the vertical blade can be implemented according to existing technology.

[0033] Example 5 In this embodiment, the two-stage pretreatment device for high-boiling-point substances can be equipped with a control unit. Temperature and pressure detection equipment, heating equipment, valves, power components (motors), etc. of the primary and secondary heating kettles can all be electrically connected to the control unit to achieve automated operation.

[0034] Example 6 In this embodiment, the two-stage pretreatment device for high-boiling-point substances can be equipped with a vacuum device to provide an internal negative pressure environment.

[0035] Example 7 The high-boiling-point recovery system in this embodiment is used to treat the high-boiling-point mixture generated in the ethylene chlorination process of PVC production. The primary steam outlet 6 and the secondary steam outlet are both connected to the feed inlet of the distillation column 102 after being condensed by a condenser.

[0036] The material is processed in the pretreatment unit. After the liquid part is vaporized, it is condensed by the condenser and enters the distillation column. The distillation column is heated by the distillation column reboiler and cooled by the distillation column condenser. The top part is refluxed and the product is drawn into the top product tank. The bottom product is pumped into the bottom liquid tank of the distillation column. Part of the liquid in the bottom liquid tank of the distillation column is returned to the solid-liquid separator as reflux liquid, and part of it is entered into the bottom product tank as bottom product. The vacuum equipment provides a negative pressure environment for the system.

[0037] The two-stage pretreatment device for high-boiling-point substances operates under negative or normal pressure and is equipped with a stirring shaft and a crushing and pushing shaft. Under the heating of the secondary heating jacket (11), the material becomes dehydrated and shaped, and enters the solid discharge port (14) to obtain a solid product. The liquid evaporated from the secondary steam outlet 16 also enters the distillation column. The solid product is jelly-like. This solid is neither too dry nor too wet. Under certain humidity, it has good properties, making the discharged solid easy to shape, non-sticky to the fabric, non-sticky to the kettle, fragile, and easy to handle, thus avoiding the defects of traditional processes.

[0038] The reflux ratio in the distillation column is 0.3 to 10:1. The height of the trays or packing in the rectifying section of the distillation column is 3 to 50 layers or 1 to 15 meters, and the height of the trays or packing in the stripping section of the distillation column is 3 to 50 layers or 1 to 15 meters.

[0039] The operating conditions for a distillation column are: top temperature 50-120℃, bottom temperature 70-180℃ (the lower the temperature, the better), pressure controlled at 10kPa~300kPa (absolute pressure), and a pressure difference of 5-15kPa between the top and bottom of the column. It is preferred to operate the entire column under negative pressure.

[0040] The bottom product of the tower is a mixture mainly composed of trichloroethylene, wherein the mass content of trichloroethylene in the mixture is 30%-50%. The mass content of 1,2-dichloroethane in the high-boiling feedstock is above 20%, preferably 25%-55%.

[0041] Adding the bottom liquid of the distillation column as reflux liquid to the solid-liquid separator can significantly improve the recovery rate of 1,2-dichloroethane in the entire system. The recovery rate of 1,2-dichloroethane can reach more than 95%, and the purity can meet the requirement of at least 80% for direct reuse, and even the purity can reach more than 95% of the raw material requirements.

[0042] This invention transforms hazardous waste into qualified reusable products. The recovered high-purity 1,2-dichloroethane can be used directly as a raw material for chlorination production of PVC. The solid portion from the solid discharge port can be reused as carbon powder, improving the environmental and economic benefits of enterprises and solving the shortcomings of existing technologies that only recover small amounts of high-boiling-point mixtures or treat them directly as hazardous waste.

[0043] Any matters not covered in this utility model are common knowledge.

Claims

1. A two-stage pretreatment device for high-boiling-point substances, characterized in that, The pretreatment device includes a primary heating vessel (3), a secondary heating tank (15), and a conveying pipe (8) connecting the primary heating vessel and the secondary heating tank. A primary heating jacket (2) is set outside the primary heating vessel (3). A high-boiling-point raw material inlet (1) and a primary steam outlet (6) are set on the upper two sides of the primary heating vessel (3). The top of the primary heating vessel (3) is sealed, and a stirring shaft motor (5) is set on its top. A stirring shaft (4) is connected below the stirring shaft motor (5). The stirring shaft (4) extends into the interior of the primary heating vessel (3). The conveying pipe (8) is located at the lower part of the primary heating vessel (3) and connected to the secondary heating tank (15); the conveying pipe (8) is provided with a conveying valve on the side near the primary heating vessel, and a stirring cage motor (10) is provided on the side connected to the secondary heating tank; a stirring cage conveying shaft (9) is provided in the conveying pipe (8), and the stirring cage conveying shaft is connected to the stirring cage motor. A secondary heating jacket (11) is provided outside the secondary heating tank (15), a solid discharge port (14) is provided at the bottom of the secondary heating tank, and a secondary steam outlet (16) is provided at the top of the secondary heating tank. The material in the secondary heating tank (15) is stirred and pushed to the solid discharge port (14) by an auxiliary stirring and pushing mechanism.

2. The two-stage pretreatment device for high-boiling-point substances according to claim 1, characterized in that, Both the primary steam outlet and the secondary steam outlet are connected to the post-treatment equipment for high-boiling-point substances.

3. The two-stage pretreatment device for high-boiling-point substances according to claim 1, characterized in that, A stirring blade is provided on the stirring shaft (4). The stirring blade is arranged in layers along the height direction of the primary heating vessel. During the rotation process, the stirring blade will not touch the wall of the primary heating vessel, and can stir all the liquid in the primary heating vessel, thus avoiding the occurrence of dead zones in the liquid stirring.

4. The two-stage pretreatment device for high-boiling-point substances according to claim 1, characterized in that, The stirring shaft is equipped with spiral stirring blades along the height direction. The stirring blades are designed to stir all the liquid in the primary heating vessel without hitting the walls, thus avoiding dead zones in the liquid stirring.

5. The two-stage pretreatment apparatus for high-boiling-point substances according to claim 1, characterized in that, The primary heating jacket and the secondary heating jacket are heated by circulating steam, hot water or heat transfer oil. The upper end of the primary heating jacket is located below the primary steam outlet, and the upper end of the primary heating jacket is not less than 1 / 4 of the height of the primary heating vessel body. The upper end of the secondary heating jacket is at the same height as the upper end of the secondary heating tank.

6. The two-stage pretreatment apparatus for high-boiling-point substances according to claim 1, characterized in that, The auxiliary stirring and pushing mechanism includes a crushing and pushing shaft (13) and a crushing and pushing motor (12). The crushing and pushing shaft is located at the lower part of the secondary heating tank (15). The crushing and pushing shaft does not contact the wall of the secondary heating tank. The crushing and pushing shaft is arranged horizontally. The secondary heating tank is a horizontal tank.

7. The two-stage pretreatment apparatus for high-boiling-point substances according to claim 1, characterized in that, The conveying pipe (8) is inclined at the lower part of the primary heating vessel (3), and the inclination angle of the conveying pipe (8) is 10°-85°; Meters are installed at the secondary steam outlet, primary steam outlet, and conveying pipeline to collect data on the secondary steam output, primary steam output, and material entering the secondary heating tank, respectively. A meter is also installed at the inlet of the high-boiling-point raw material. The conveying valve is normally closed.

8. The two-stage pretreatment apparatus for high-boiling-point substances according to claim 1, characterized in that, The auxiliary stirring and pushing mechanism includes a scraper and a vertical blade.

9. A high-boiling-point substance recovery system using the two-stage pretreatment device for high-boiling-point substances as described in claim 1, characterized in that, The high-boiling-point raw material inlet is connected to the pipeline for conveying the high-boiling-point mixture to be recovered, and both the primary steam outlet and the secondary steam outlet are connected to the high-boiling-point post-processing equipment.

10. The system according to claim 9, characterized in that, The high-boiling-point mixture is a mixture of high-boiling-point substances produced in the ethylene chlorination process of PVC production, mainly composed of 1,2-dichloroethane.

Images