Polyester esterification reactor capable of being cleaned on line

Abstract

The utility model discloses a polyester esterification reactor capable of being cleaned on line, and relates to the technical field of esterification reaction devices. An inlet of the first heat exchange branch is communicated with the bottom of the esterification reactor, an outlet of the first heat exchange branch is communicated with the side face of the esterification reactor, and the outlet of the first heat exchange branch is higher than the liquid level of the esterification reactor; the first heat exchanger is arranged on the first heat exchange branch in a communicating manner; an inlet of the second heat exchange branch is communicated with the bottom of the esterification reactor, an outlet of the second heat exchange branch is communicated with the side face of the esterification reactor, the outlet of the second heat exchange branch is higher than the liquid level of the esterification reactor, and the second heat exchange branch is connected with the first heat exchange branch in parallel; and the second heat exchanger communicates with the second heat exchange branch. The esterification reaction device solves the technical problem that a heat exchange part of an existing esterification reaction device is difficult to clean.

Description

Technical Field

[0001] The utility model relates to the technical field of esterification reaction devices, in particular to a polyester esterification reactor capable of being cleaned online. Background Art

[0002] At present, the domestic polyester industry, especially PBT and PBS polyesters, has an esterification reaction temperature that is ~40°C lower than that of traditional PET (polyethylene terephthalate), so most of them use titanate catalysts with good low-temperature activity.

[0003] However, titanate catalysts and the water produced in the esterification reaction are prone to hydrolysis reaction, generating a catalytically inactive hydrolysis product Ti(OH)4. Under the action of the heat source of the esterification kettle, Ti(OH)4 is dehydrated and decomposed into TiO2 solid, which adheres to the heat exchange tubes in the esterification kettle, thereby affecting the heat transfer of the equipment. Specifically, the following problems will arise: (1) After 6 to 10 months of normal operation, the esterification kettle of PBT and PBS polyesters will stop for cleaning due to scaling, causing the heat transfer efficiency to drop to a threshold. For continuous polyester production lines, one start and stop will affect production for at least one week, and a lot of transition materials or waste will be generated during the start and stop, affecting the economic benefits of the enterprise. (2) When cleaning the heat exchange tubes of the esterification kettle of PBT and PBS polyesters, workers usually need to enter the equipment inside the esterification kettle to clean the heat exchange tubes, which poses safety hazards such as high temperature, suffocation, and toxic gas injuries. Utility Model Content

[0004] The purpose of the utility model is to provide a polyester esterification reactor that can be cleaned online, which solves the technical problem of difficulty in cleaning heat exchange components of esterification reaction devices in the prior art.

[0005] The present application discloses an online cleaning polyester esterification reactor, comprising:

[0006] Esterification reactor;

[0007] a first heat exchange branch, wherein the inlet of the first heat exchange branch is connected to the bottom of the esterification reactor, and the outlet of the first heat exchange branch is connected to the side of the esterification reactor, and the outlet of the first heat exchange branch is higher than the liquid level of the esterification reactor;

[0008] a first heat exchanger, connected to the first heat exchange branch;

[0009] a second heat exchange branch, wherein the inlet of the second heat exchange branch is connected to the bottom of the esterification reactor, and the outlet of the second heat exchange branch is connected to the side of the esterification reactor, the outlet of the second heat exchange branch is higher than the liquid level of the esterification reactor, and the second heat exchange branch is connected in parallel with the first heat exchange branch;

[0010] The second heat exchanger is connected to the second heat exchange branch.

[0011] The present application is provided with external first and second heat exchangers, so as to achieve non-stop cleaning of the entire system and ensure work efficiency.

[0012] Based on the above technical solution, the embodiment of the present application can also be improved as follows:

[0013] Furthermore, the first heat exchange branch and the second heat exchange branch are both provided with a shut-off valve. The beneficial effect of adopting this step is to realize the switching of different heat exchange branches through the shut-off valve.

[0014] Furthermore, the first heat exchange branch and the second heat exchange branch are both provided with detachable pipes. The beneficial effect of adopting this step is to facilitate the disassembly of the heat exchanger.

[0015] Furthermore, the heat source inlet of the first heat exchanger and the heat source inlet of the second heat exchanger are both installed with temperature regulating valves. The beneficial effect of adopting this step is to ensure the quality of the product by adjusting the heat source flow.

[0016] Furthermore, the first and second heat exchangers are both shell and tube reboilers, and the beneficial effect of this step facilitates subsequent cleaning.

[0017] Furthermore, the esterification reactor is a vertical fully mixed kettle.

[0018] Furthermore, the outer wall of the esterification reactor is provided with a heat-insulating sleeve. The beneficial effect of adopting this step is to play a heat-insulating role.

[0019] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0020] 1. This application adopts an external heat exchanger, which does not require the esterification kettle to be stopped for cleaning. The maintenance cycle of the original device can be increased from 6 to 10 months to 3 to 4 years, which greatly reduces the generation of transition materials or waste materials during the start-up and shutdown process, and indirectly improves the production capacity of the device and improves the economic benefits of the enterprise.

[0021] 2. This application can clean the heat exchanger separately, without the need for workers to enter the esterification kettle to clean the heat exchange tubes, reducing the safety risks of the enterprise and improving the safety of workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is a structural schematic diagram of an online-cleanable polyester esterification reactor according to a specific embodiment of the present utility model;

[0024] Reference numerals:

[0025] 1-esterification reactor; 2-first heat exchange branch; 3-first heat exchanger; 4-second heat exchange branch; 5-second heat exchanger; 6-shut-off valve; 7-temperature regulating valve; 8-insulation jacket; 9-detachable pipeline. DETAILED DESCRIPTION

[0026] The following embodiments of the technical solution of the present invention are described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0027] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which this utility model belongs.

[0028] In this application, unless otherwise specified or limited, the terms "installed," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections; direct connections, or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0029] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0030] Example:

[0031] like Figure 1 As shown, the present application discloses a polyester esterification reactor that can be cleaned online. By providing two external heat exchangers, the detachable pipe 9 can be disassembled separately and the heat exchange tube can be cleaned to clean the TiO2 solids. At the same time, the other heat exchanger can be activated to ensure the stable operation of the entire device without affecting the operation of the entire device.

[0032] The specific structure of this application includes:

[0033] Esterification reactor 1, which is the main body of the reaction and is used to carry out the esterification reaction;

[0034] a first heat exchange branch 2, wherein the inlet of the first heat exchange branch 2 is connected to the bottom of the esterification reactor 1, and the outlet of the first heat exchange branch 2 is connected to the side of the esterification reactor 1, and the outlet of the first heat exchange branch 2 is higher than the liquid level of the esterification reactor 1;

[0035] The first heat exchanger 3 is connected to the first heat exchange branch 2. The first heat exchanger 3 is an external heat exchanger, so it can be directly disassembled for cleaning during subsequent cleaning to ensure the safety of employees;

[0036] A second heat exchange branch 4, the inlet of the second heat exchange branch 4 is connected to the bottom of the esterification reactor 1, and the outlet of the second heat exchange branch 4 is connected to the side of the esterification reactor 1, the outlet of the second heat exchange branch 4 is higher than the liquid level of the esterification reactor 1, the second heat exchange branch 4 is connected in parallel with the first heat exchange branch 2, and the second heat exchange branch 4 and the first heat exchange branch 2 in the present application are connected in parallel, so that it can be used as a backup to ensure that the operation of the entire system is not affected when the heat exchanger is cleaned;

[0037] The second heat exchanger 5 is connected to the second heat exchange branch 4. The second heat exchanger 5 is an external heat exchanger and has a similar function to the first heat exchanger 3, and can ensure the safety of employees.

[0038] Specifically, in the present application, a shut-off valve 6 is provided on both the first heat exchange branch 2 and the second heat exchange branch 4. Preferably, there are two shut-off valves 6 on the first heat exchange branch 2, which are located at both ends of the first heat exchanger 3, so that the shut-off can be performed to ensure that the front and rear ends of the first heat exchanger 3 are cut off, and then the first heat exchanger 3 is removed for separate cleaning. At this time, the second heat exchange branch 4 is activated for heat exchange; conversely, the first heat exchange branch 2 is activated and the second heat exchanger 5 is removed for cleaning.

[0039] In order to facilitate the disassembly of the first heat exchanger 3 or the second heat exchanger 5, the first heat exchange branch 2 and the second heat exchange branch 4 in the present application are both provided with a detachable pipe 9. Specifically, the detachable pipe 9 is respectively located at the upper and lower ends of the first heat exchanger 3 and the upper and lower ends of the second heat exchanger 5.

[0040] In order to adjust the flow rate of the heat source fluid and accurately control the temperature of the material in the reactor, the present application installs temperature regulating valves 7 at the heat source inlet of the first heat exchanger 3 and the heat source inlet of the second heat exchanger 5, so as to better ensure the quality of the product.

[0041] Specifically, the first and second heat exchangers are both shell and tube reboilers, which serve as backup for each other, thus facilitating disassembly.

[0042] Specifically, the esterification reactor 1 is a vertical fully mixed kettle.

[0043] In order to avoid heat loss in the esterification reactor 1 , the outer wall of the esterification reactor 1 described in the present application is provided with a heat insulation jacket 8 .

[0044] Further explanation of this application:

[0045] The present application is a polyester esterification reactor that can be cleaned online. There is no need to stop the esterification kettle to clean it, nor is there a need for workers to enter the esterification kettle to clean the heat exchange tubes. It is only necessary to disassemble the external first and second heat exchangers for cleaning.

[0046] The esterification reactor in the present application is a vertical fully mixed kettle (which can be equipped with an agitator, a reducer, an electric motor, etc.), which can be used for reaction temperatures of 130°C to 280°C, reaction pressures of 10KPa to 0.3MPa absolute pressure, and residence time of the reaction raw materials of 0.5 hours to 6 hours, with a wide range of applications. At the same time, the present application is provided with an insulating jacket but no heating coil is provided, which can reduce heat loss. A jacket, heating pipe, electric heating or insulation material can also be used.

[0047] The esterification reactor in the present application is provided with an external heat exchanger, namely the first heat exchanger 3 and the second heat exchanger 5. A plurality of external heat exchangers may also be provided, wherein the first and second heat exchangers are both shell and tube reboilers, serving as backup units for each other. At the same time, the present application is also provided with a detachable pipe located at the inlet and outlet ends of the first and second heat exchangers, so as to facilitate the cleaning of the first and second heat exchangers. Specifically, when the first heat exchanger is scaled to the point where it cannot work normally and the heat exchange tubes need to be cleaned, the spare second heat exchanger is first activated, the shut-off valve of the first heat exchanger is closed, the detachable pipes at the inlet and outlet of the first heat exchanger are removed, and the scale on the heat exchange tubes is cleaned. After completion, the detachable section is installed and kept ready for use. Similarly, if the second heat exchanger is scaled to the point where it cannot work normally, the same operation is followed.

[0048] In the present application, temperature regulating valves are provided on the heat source inlet and outlet pipes of the first heat exchanger and the second heat exchanger, so as to accurately control the temperature of the material in the reactor by adjusting the flow rate of the heat source fluid.

[0049] The outlets of the first heat exchanger 3 and the second heat exchanger 5 in the present application are higher than the liquid level in the esterification reactor, which can reduce the contact between the water produced by the reaction and the titanate catalyst.

[0050] In the specification of the present invention, a large number of specific details are described. However, it is understood that the embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0051] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. A polyester esterification reactor capable of online cleaning, characterized in that: include: Esterification reactor (1); a first heat exchange branch (2), wherein the inlet of the first heat exchange branch (2) is connected to the bottom of the esterification reactor (1), and the outlet of the first heat exchange branch (2) is connected to the side of the esterification reactor (1), and the outlet of the first heat exchange branch (2) is higher than the liquid level of the esterification reactor (1); A first heat exchanger (3) is arranged in communication with the first heat exchange branch (2); a second heat exchange branch (4), wherein the inlet of the second heat exchange branch (4) is connected to the bottom of the esterification reactor (1), and the outlet of the second heat exchange branch (4) is connected to the side of the esterification reactor (1), the outlet of the second heat exchange branch (4) is higher than the liquid level of the esterification reactor (1), and the second heat exchange branch (4) is connected in parallel with the first heat exchange branch (2); The second heat exchanger (5) is arranged in communication with the second heat exchange branch (4).

2. The polyester esterification reactor according to claim 1, characterized in that Both the first heat exchange branch (2) and the second heat exchange branch (4) are provided with a shut-off valve (6).

3. The polyester esterification reactor according to claim 1, characterized in that The first heat exchange branch (2) and the second heat exchange branch (4) are both provided with detachable pipes (9).

4. The polyester esterification reactor according to claim 1, characterized in that The heat source inlet of the first heat exchanger (3) and the heat source inlet of the second heat exchanger (5) are both installed with temperature regulating valves (7).

5. The polyester esterification reactor according to claim 1, characterized in that The first and second heat exchangers are both shell and tube reboilers.

6. The polyester esterification reactor according to claim 5, characterized in that The esterification reactor (1) is a vertical fully mixed kettle.

7. The polyester esterification reactor according to claim 6, characterized in that The outer wall of the esterification reactor (1) is provided with a heat insulation sleeve (8).

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