A heat exchange device for a long-running extruder hot oil system

Abstract

This utility model discloses a heat exchange device for a long-running extruder hot oil system, comprising a demineralized water tank, a demineralized water circulating pump, a melt-mixing section cold oil cooler, a melt pump high-temperature oil cooler, and a demineralized water cooler. The demineralized water tank is connected to a demineralized water outlet pipeline, which is connected to the cold medium inlet of the melt-mixing section cold oil cooler via a first pipeline. The demineralized water outlet pipeline is also connected to the cold medium inlet of the melt pump high-temperature oil cooler via a second pipeline. The cold medium outlets of the melt-mixing section cold oil cooler and the melt pump high-temperature oil cooler are connected to the hot medium inlet of the demineralized water cooler. The hot medium outlet of the demineralized water cooler is connected to the circulating demineralized water inlet of the demineralized water tank. This device solves the core problems of severe scaling and short operating cycles in existing technologies, and can improve production continuity, reduce annual maintenance costs, and save labor and improve efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of polypropylene production technology, specifically relating to a heat exchange device for a hot oil system of an extruder with a long operating cycle. Background Technology

[0002] In the polypropylene production process, polypropylene powder and additives are mixed and fed into the extruder barrel, where they are extruded and melted at high temperatures. During normal operation, the extruder unit utilizes a hot oil system to heat / cool the extruder barrel (sections 2-9) and the melt pump, controlling the temperature range between 180℃ and 320℃. In this hot oil system, heat exchangers, such as the cold oil cooler in the melt mixing section and the high-temperature oil cooler in the melt pump, are used for cooling the hot oil in either the extruder barrel or the melt pump. However, due to the high temperature of the hot oil (>180℃), the heat exchangers operate at scaling temperatures for extended periods, resulting in decreased heat exchange efficiency. Furthermore, cleaning requires more than 24 hours, severely impacting production continuity. Currently, the operating cycle is only about 12 months, which cannot meet the requirements for long-term operation. Utility Model Content

[0003] The purpose of this invention is to provide a heat exchange device for an extruder hot oil system with a long operating cycle, which solves the problem of heat exchanger scaling mentioned in the background art and extends the operating cycle of the heat exchange system.

[0004] This utility model is implemented by the following technical solution:

[0005] A heat exchange device for a long-running extruder hot oil system includes a melt-mixing section cold oil cooler for cooling hot oil in sections 2-9 of the extruder barrel, a melt pump high-temperature oil cooler for cooling hot oil in the melt pump, a demineralized water tank for storing demineralized water, and a demineralized water cooler for removing heat from the demineralized water after cooling the hot oil. The demineralized water tank's circulating demineralized water outlet is connected to a demineralized water outflow pipeline, on which a demineralized water circulation pump is installed to provide a stable flow rate, increase demineralized water pressure, and enhance heat exchange efficiency. The demineralized water outflow pipeline is connected to the cold medium inlet of the melt-mixing section cold oil cooler via a first pipeline, and the cold medium outlet of the melt-mixing section cold oil cooler is connected to the hot medium inlet of the demineralized water cooler. The demineralized water outflow pipeline is connected to the cold medium inlet of the melt pump high-temperature oil cooler via a second pipeline, and the cold medium outlet of the melt pump high-temperature oil cooler is connected to the hot medium inlet of the demineralized water cooler. The hot medium outlet of the demineralized water cooler is connected to the circulating demineralized water inlet of the demineralized water tank.

[0006] In the hot oil system, the demineralized water in the demineralized water tank flows through the first pipeline and the second pipeline into the cold oil cooler of the melting and mixing section and the high-temperature oil cooler of the melting pump, respectively, as a cold medium to exchange heat with the hot oil. After the heat exchange, the temperature of the demineralized water rises as a cold medium, and then it enters the demineralized water cooler as a hot medium to cool down. After cooling, the demineralized water returns to the demineralized water tank for continued use, forming a closed demineralized water system, reducing the entry of scaling substances and making it less prone to scaling. The arrangement of the demineralized water tank, demineralized water cooler and related pipelines helps to improve the heat exchange effect of the heat exchanger of the hot oil system. The arrangement of heat exchange pipelines can improve the heat exchange efficiency by 15%-20%.

[0007] Furthermore, the pure nitrogen inlet of the demineralized water tank is connected to a pure nitrogen pipeline. Pure nitrogen is continuously introduced into the top space of the demineralized water tank to form an inert gas covering layer, which isolates the air, especially CO2, from contact with water, reducing the risk of scaling such as carbonate formation.

[0008] Furthermore, the demineralized water tank is equipped with a conductivity meter, an online pH meter, and a first thermometer; the wastewater outlet of the demineralized water tank is connected to a wastewater discharge pipeline, and a first solenoid valve is installed on the wastewater discharge pipeline. The demineralized water in the demineralized water tank is periodically tested. When the conductivity meter detects that the conductivity of the demineralized water exceeds the standard, the online pH meter detects that the pH of the demineralized water exceeds the standard, and the first thermometer detects that the temperature of the demineralized water exceeds the standard, the first solenoid valve is opened, and the demineralized water in the tank is discharged as wastewater or sent to other processes for treatment.

[0009] Furthermore, the demineralized water tank is equipped with a level gauge; the water inlet of the demineralized water tank is connected to a water supply pipeline; a second thermometer is installed at the inlet end of the water supply pipeline; a water supply cooler is also included; the heat medium inlet of the water supply cooler is connected to the water supply pipeline between the second thermometer and the demineralized water tank via a cooling water supply pipeline, the water supply pipeline between the cooling water supply pipeline and the demineralized water tank is a conventional water supply pipeline, the heat medium outlet of the water supply cooler is connected to the conventional water supply pipeline; a second solenoid valve is installed on the cooling water supply pipeline, a third solenoid valve is installed on the conventional water supply pipeline; the heat medium outlet of the water supply cooler is connected to the water supply inlet of the demineralized water tank. When the amount of demineralized water discharged from the demineralized water tank exceeds the standard, the level gauge detects a drop in the liquid level. At this time, demineralized water is replenished through the water supply pipeline. The incoming water temperature is monitored by the second thermometer. If the incoming water temperature meets the requirements, the second solenoid valve is closed and the third solenoid valve is opened, and the replenished demineralized water is supplied to the demineralized water tank through the conventional water supply pipeline. If the incoming water temperature is high, the third solenoid valve is closed and the second solenoid valve is opened, so that the replenished demineralized water first enters the water supply cooler through the cooling water supply pipeline to cool the replenished demineralized water before it is introduced into the demineralized water tank.

[0010] Furthermore, it also includes a controller; the signal input terminal of the controller is connected to the signal output terminals of the conductivity meter, the online pH meter, the first thermometer, the second thermometer, and the level gauge; the signal output terminal of the controller is connected to the signal input terminals of the first solenoid valve, the second solenoid valve, and the third solenoid valve. The controller enables online drainage and water replenishment of this device, saving labor and improving efficiency.

[0011] Beneficial effects: This utility model provides a heat exchange device for a long-running extruder hot oil system. Through the demineralized water tank, demineralized water cooler, and their pipeline connection with the heat exchanger in the hot oil system, the hot oil cooling function of the heat exchanger is completed, solving the core problems of severe scaling and short operating cycle in the prior art. It can also improve production continuity and reduce annual maintenance costs. Through the setting of controllers and instruments, water quality monitoring and online drainage and water replenishment can be realized, which is conducive to saving labor and improving efficiency. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of this utility model;

[0014] Figure 2 This is a schematic diagram of the controller's signal connections.

[0015] The attached diagram is described below:

[0016] 10. Demineralized water tank; 11. Makeup water cooler; 12. Conductivity meter; 13. Online pH meter; 14. First thermometer; 15. Level gauge; 16. Second thermometer; 17. First solenoid valve; 18. Second solenoid valve; 19. Third solenoid valve; 20. Demineralized water circulation pump; 30. Melt mixing section cold oil cooler; 40. Melt pump high-temperature oil cooler; 50. Demineralized water cooler; 60. Controller;

[0017] L1, Demineralized water outflow pipeline; L2, First pipeline; L3, Second pipeline; L4, Pure nitrogen pipeline; L5, Wastewater discharge pipeline; L6, Water replenishment pipeline; L7, Cooling water replenishment pipeline; L8, Conventional water replenishment pipeline. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present utility model. In addition, the terms "first", "second", etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. 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.

[0019] Example

[0020] A heat exchange device for an extruder hot oil system with a long operating cycle, such as Figure 1 As shown, it includes a demineralized water tank 10, a melt mixing section cold oil cooler 30, a melt pump high-temperature oil cooler 40, and a demineralized water cooler 50.

[0021] The demineralized water tank 10 has a circulating demineralized water outlet connected to a demineralized water outlet pipeline L1, on which a demineralized water circulation pump 20 is installed. The demineralized water outlet pipeline L1 is connected to the cold medium inlet of the melt mixing section cold oil cooler 30 via a first pipeline L2. The cold medium outlet of the melt mixing section cold oil cooler 30 is connected to the hot medium inlet of the demineralized water cooler 50. The hot medium of the melt mixing section cold oil cooler 30 is hot oil in the hot oil system. The demineralized water outlet pipeline L1 is connected to the cold medium inlet of the melt pump high-temperature oil cooler 40 via a second pipeline L3. The cold medium outlet of the melt pump high-temperature oil cooler 40 is connected to the hot medium inlet of the demineralized water cooler 50. The hot medium of the melt pump high-temperature oil cooler 40 is hot oil in the hot oil system. The hot medium outlet of the demineralized water cooler 50 is connected to the circulating demineralized water inlet of the demineralized water tank 10. The cold medium inlet of the demineralized water cooler 50 is connected to a circulating water supply pipeline, and the cold medium outlet of the demineralized water cooler 50 is connected to a circulating water return pipeline. In this embodiment, circulating water supply lines are connected to the cold medium inlet of the cold oil cooler 30 in the molten mixing section and the cold medium inlet of the high-temperature oil cooler 40 in the molten pump. Circulating water return lines are also connected to the cold medium outlet of the cold oil cooler 30 in the molten mixing section and the cold medium outlet of the high-temperature oil cooler 40 in the molten pump. During periods of water replenishment or demineralized water system failure, circulating water can be temporarily used to ensure continuous heat exchange operation. In this embodiment, a bypass line is also provided. The inlet of the bypass line is connected to the demineralized water outlet line L1 after the demineralized water circulating pump 20, and the outlet of the bypass line is connected to the circulating demineralized water inlet of the demineralized water tank 10. This can be used to dynamically balance the demineralized water outlet flow rate and pressure, and to maintain operation during heat exchanger maintenance or shutdown.

[0022] The demineralized water tank 10 is equipped with a conductivity meter 12, an online pH meter 13, a first thermometer 14, and a level gauge 15.

[0023] The demineralized water tank 10 has a pure nitrogen inlet connected to a pure nitrogen pipeline L4, and a pressure relief valve is installed on the top of the demineralized water tank 10. The demineralized water tank 10 is also connected to a heated water supply pipeline and a heated water return pipeline, which can be used to insulate the demineralized water inside the tank 10 when the winter temperature is too low (in this embodiment, the demineralized water temperature is controlled between 20~40℃), preventing freezing or temperature fluctuations from affecting water quality. Furthermore, low-temperature demineralized water dissolves CO2 more easily, and the heating system further reduces scaling. The wastewater outlet of the demineralized water tank 10 is connected to a wastewater discharge pipeline L5, and a first solenoid valve 17 is installed on the wastewater discharge pipeline L5. The demineralized water tank 10 has a water supply inlet connected to a water supply pipeline L6; a second thermometer 16 is installed at the inlet of the water supply pipeline L6; it also includes a water supply cooler 11; the cold medium inlet of the water supply cooler 11 is connected to a circulating water supply pipeline, and the cold medium outlet of the water supply cooler 11 is connected to a circulating water return pipeline; the hot medium inlet of the water supply cooler 11 is connected to the water supply pipeline L6 between the second thermometer 16 and the demineralized water tank 10 via a cooling water supply pipeline L7; the water supply pipeline L6 between the cooling water supply pipeline L7 and the demineralized water tank 10 is a conventional water supply pipeline L8; the hot medium outlet of the water supply cooler 11 is connected to the conventional water supply pipeline L8; a second solenoid valve 18 is installed on the cooling water supply pipeline L7, and a third solenoid valve 19 is installed on the conventional water supply pipeline L8; the hot medium outlet of the water supply cooler 11 is connected to the water supply inlet of the demineralized water tank 10.

[0024] It also includes controller 60; such as Figure 2 As shown, the signal input terminal of the controller 60 is connected to the signal output terminal of the conductivity meter 12, the signal output terminal of the online pH meter 13, the signal output terminal of the first thermometer 14, the signal output terminal of the level gauge 15, and the signal output terminal of the second thermometer 16; the signal output terminal of the controller 60 is connected to the signal input terminal of the first solenoid valve 17, the signal input terminal of the second solenoid valve 18, and the signal input terminal of the third solenoid valve 19.

[0025] The working principle is as follows:

[0026] In the hot oil system, the demineralized water in the demineralized water tank 10 flows through the demineralized water outlet pipeline L1. Under the pressure of the demineralized water circulation pump 20, it flows through the first pipeline L2 and the second pipeline L3 into the cold oil cooler 30 of the melting and mixing section and the high-temperature oil cooler 40 of the melting pump, respectively. As a cold medium, it exchanges heat with the hot oil. After the heat exchange, the temperature of the demineralized water rises as a cold medium. It then enters the demineralized water cooler 50 as a hot medium for cooling. After cooling, the demineralized water returns to the demineralized water tank 10 for recycling.

[0027] The demineralized water in the demineralized water tank 10 is tested periodically (every 72 hours in this embodiment, or continuous online monitoring can also be maintained). When the conductivity meter 12 detects that the conductivity of the demineralized water is >10 μS / cm and / or the online pH meter detects that the pH of the demineralized water is >7.5 and / or the first thermometer detects that the temperature of the demineralized water is >40°C, the first solenoid valve is opened through the signal transmission of the controller 60, and the demineralized water in the tank is discharged as wastewater through the wastewater discharge pipeline L5 or sent to other processes for treatment. When the amount of demineralized water discharged from the demineralized water tank 10 exceeds the standard, the level gauge 14 detects a drop in the liquid level. At this time, demineralized water is replenished through the water replenishment line L6. Table 1 below shows the relevant indicators of the replenished demineralized water sampled from the water replenishment line L6 during a certain period of the test. The incoming water temperature is monitored by the second thermometer 16. If the incoming water temperature is ≤40℃, the controller 60 controls the second solenoid valve 18 to close and the third solenoid valve 19 to open, and the replenished demineralized water is replenished into the demineralized water tank through the conventional water replenishment line L8. If the incoming water temperature is >40℃, the controller 60 controls the third solenoid valve 19 to close and the second solenoid valve 18 to open, so that the replenished demineralized water first enters the water replenishment cooler 11 through the cooling water replenishment line L7 to cool down the replenished demineralized water before it is introduced into the demineralized water tank 10.

[0028] Table 1 Supplementary Desalinated Water Quality Indicators

[0029]

[0030] After applying this device, the heat exchange efficiency is increased by 15-20%, the scaling rate is reduced by 75%, and the heat exchanger operating cycle is extended to more than 48 months; in addition, production continuity is improved, and the annual maintenance cost is reduced by 75%, resulting in significant economic benefits.

[0031] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A long run extruder hot oil system heat exchanger apparatus comprising a melt mixing section cold oil cooler, a melt pump high temperature oil cooler, characterized by, It also includes a demineralized water tank and a demineralized water cooler; the demineralized water outlet of the demineralized water tank is connected to a demineralized water outflow pipeline, and a demineralized water circulation pump is installed on the demineralized water outflow pipeline; The demineralized water outflow pipeline is connected to the cold medium inlet of the melt mixing section cold oil cooler via a first pipeline, and the cold medium outlet of the melt mixing section cold oil cooler is connected to the hot medium inlet of the demineralized water cooler. The demineralized water outflow pipeline is connected to the cold medium inlet of the high-temperature oil cooler of the molten pump via a second pipeline, and the cold medium outlet of the high-temperature oil cooler of the molten pump is connected to the hot medium inlet of the demineralized water cooler. The hot medium outlet of the demineralized water cooler is connected to the circulating demineralized water inlet of the demineralized water tank.

2. The heat exchanger device of the long running period extruder hot oil system according to claim 1, characterized in that, The pure nitrogen inlet of the demineralized water tank is connected to a pure nitrogen pipeline.

3. The heat exchanger device of claim 1, wherein, The demineralized water tank is equipped with a conductivity meter, an online pH meter, and a first thermometer; the wastewater outlet of the demineralized water tank is connected to a wastewater discharge pipeline, and a first solenoid valve is installed on the wastewater discharge pipeline.

4. The heat exchanger device of claim 3, wherein, The demineralized water tank is equipped with a level gauge; the water inlet of the demineralized water tank is connected to a water supply pipeline; a second thermometer is installed at the inlet end of the water supply pipeline; a water supply cooler is also included; the heat medium inlet of the water supply cooler is connected to the water supply pipeline between the second thermometer and the demineralized water tank via a cooling water supply pipeline, the water supply pipeline between the cooling water supply pipeline and the demineralized water tank is a conventional water supply pipeline, the heat medium outlet of the water supply cooler is connected to the conventional water supply pipeline; a second solenoid valve is installed on the cooling water supply pipeline, a third solenoid valve is installed on the conventional water supply pipeline; the heat medium outlet of the water supply cooler is connected to the water supply inlet of the demineralized water tank.

5. A heat exchange device for a long-running extruder hot oil system according to claim 4, characterized in that, It also includes a controller; the signal input terminal of the controller is connected to the signal output terminal of the conductivity meter, the signal output terminal of the online pH meter, the signal output terminal of the first thermometer, the signal output terminal of the second thermometer, and the signal output terminal of the level gauge; the signal output terminal of the controller is connected to the signal input terminal of the first solenoid valve, the signal input terminal of the second solenoid valve, and the signal input terminal of the third solenoid valve.

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