Energy recycling system for polyformaldehyde process
By introducing a recovery tower bottom reboiler and a methanol recovery tower during the polyformaldehyde production process, the heat exchange of triformaldehyde gas with the recovery tower bottom material was solved, and the heat problem of unused heat at the top of the triformaldehyde reboiling tower was solved. Improves energy recovery and reduces production costs.
Patent Information
- Application Number
- CN202420819485.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-19
- Publication Date
- 2025-01-03
- Estimated Expiration
- 2034-04-19
AI Technical Summary
During the polyformaldehyde production process, the heat produced on the top of the paraformaldehyde reboiling tower is not effectively utilized, resulting in an increase in the workload of downstream heat exchange equipment and a low energy utilization rate.
A polyformaldehyde process energy recycling system was designed. By setting up a recovery tower bottom reboiler and methanol recovery tower on the top of the triformaldehyde reboiling tower, the heat exchange of triformaldehyde gas and the recovery tower bottom material is improved. Energy recovery and utilization rate, and effective heat transport through circulating pumps and valve controls.
It improves energy utilization, reduces the workload and production costs of downstream heat exchange equipment, and realizes efficient heat recycling.
Smart Images
Figure CN222286435U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of heat energy recovery, in particular to a polyoxymethylene process energy recovery and utilization system. Background Art
[0002] Polyoxymethylene (POM), the full name of polyoxymethylene resin, is a linear polymer without side chains, high density, high crystallinity, and has excellent heat resistance, wear resistance, oil resistance, peroxide resistance, fatigue resistance, etc. The monomer raw material of POM, trioxymethylene, is polymerized by high-concentration formaldehyde through a catalyst. When the high-concentration trioxymethylene is at a high temperature and low pressure, it can be used as a medium energy source like medium steam. Even if the temperature drops to become crystalline trioxymethylene, it will become a liquid and flow normally after the temperature rises.
[0003] At present, in the production process of trioxymethylene, it will be concentrated and purified through a trioxymethylene reboiling tower. The top of the trioxymethylene reboiling tower of the trioxymethylene plant will produce trioxymethylene gas. Furthermore, in order to obtain liquid trioxymethylene and transport it downstream for subsequent polymerization reactions, the trioxymethylene gas produced at the top of the tower needs to pass through several heat exchangers and then enter the condensate receiving tank of the condenser.
[0004] However, in this process, a large amount of heat is generated when trioxymethylene gas is produced at the top of the trioxymethylene reboiling tower. If this part of heat is not utilized, it will directly enter the downstream primary heat exchanger and secondary heat exchanger, which not only increases the workload of the downstream heat exchange equipment, but also causes unnecessary waste of heat of the top material of the trioxymethylene reboiling tower, resulting in low energy utilization rate. Utility Model Content
[0005] In view of the defects of the prior art, the utility model provides a polyoxymethylene process energy recovery and utilization system, which can utilize the heat of the top material of the trioxymethylene reboiling tower in the trioxymethylene refining system, improve the energy utilization rate, and reduce the workload of the downstream heat exchange equipment.
[0006] In order to achieve the above-mentioned purpose, the technical solution provided by the utility model is a polyoxymethylene process energy recovery and utilization system, which includes a trioxymethylene reboiling tower, a primary heat exchanger, a secondary heat exchanger, a first condenser, a top reflux pump, a recovery tower bottom reboiler, a methanol recovery tower, and a second condenser; the primary heat exchanger is connected to the top of the trioxymethylene reboiling tower; the secondary heat exchanger is connected to the primary heat exchanger; the first condenser is connected to the secondary heat exchanger; the top reflux pump is connected to the first condenser, and the top reflux pump is connected to the top of the trioxymethylene reboiling tower; the recovery tower bottom reboiler is connected to the top of the trioxymethylene reboiling tower; the bottom of the methanol recovery tower is connected to the recovery tower bottom reboiler; the second condenser is connected to the recovery tower bottom reboiler, and the second condenser is connected to the secondary heat exchanger.
[0007] Furthermore, a circulation pump is provided on the pipeline between the second condenser and the secondary heat exchanger.
[0008] Furthermore, the top of the trioxymethylene reboiling tower is connected to the primary heat exchanger via a top discharge pipeline.
[0009] Furthermore, a first valve is provided on the tower top discharge pipeline.
[0010] Furthermore, the top of the trioxymethylene reboiling tower is connected to the reboiler at the bottom of the recovery tower through an energy recovery pipeline.
[0011] Furthermore, a second valve is provided on the energy recovery pipeline.
[0012] Furthermore, the energy recovery pipeline meets the tower top discharge pipeline upstream of the first valve.
[0013] Furthermore, the tower top reflux pump is connected to the tower top of the trioxymethylene reboiling tower through a reflux pipeline.
[0014] Furthermore, the reflux line is provided with a third valve.
[0015] During the production process, trioxymethylene gas and a large amount of heat will be produced at the top of the trioxymethylene reboiling tower. The trioxymethylene gas enters the bottom reboiler of the recovery tower from the top of the trioxymethylene reboiling tower, and exchanges heat with the material flowing out from the bottom of the methanol recovery tower to utilize the heat accompanying the trioxymethylene gas and provide the heat of trioxymethylene to the bottom reboiler of the recovery tower, thereby achieving the effect of improving the energy recovery rate. The trioxymethylene gas that has passed through the bottom reboiler of the recovery tower enters the condensate receiving tank of the second condenser and is pumped to the secondary heat exchanger for cooling, and finally converges to the condensate receiving tank of the first condenser.
[0016] The beneficial effects of the utility model are as follows: a pipeline is added to the gas phase pipeline from the trioxymethylene reboiling tower to the primary heat exchanger, so that a large amount of heat brought by the trioxymethylene is transported to the bottom reboiler of the recovery tower at the bottom of the methanol recovery tower. This process can simultaneously reduce the energy consumption of the primary heat exchanger and the bottom reboiler of the recovery tower, so as to achieve the purpose of improving the energy recovery utilization rate, thereby reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 This is a process flow chart of a polyoxymethylene process energy recovery and utilization system in one embodiment of the utility model;
[0018] In the figure:
[0019] 100. Trioxymethylene reboiling tower, 110. Tower top discharge pipeline, 111. First valve, 120. Energy recovery pipeline, 121. Second valve,
[0020] 200. Primary heat exchanger,
[0021] 300, secondary heat exchanger,
[0022] 400, the first condenser,
[0023] 500, tower top reflux pump, 510, reflux pipeline, 511, third valve,
[0024] 600, Recovery tower bottom reboiler,
[0025] 700, methanol recovery tower,
[0026] 800. The second condenser. 810. The circulating pump. DETAILED DESCRIPTION
[0027] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model, so the utility model is not limited by the specific embodiments disclosed below.
[0028] See also Figure 1, shows a process flow chart of a polyoxymethylene process energy recovery and utilization system in one embodiment of the utility model, which includes a trioxymethylene reboiling tower 100, a primary heat exchanger 200, a secondary heat exchanger 300, a first condenser 400, a tower top reflux pump 500, a recovery tower bottom reboiler 600, a methanol recovery tower 700, and a second condenser 800; the primary heat exchanger 200 is connected to the top of the trioxymethylene reboiling tower 100; the secondary heat exchanger 300 is connected to the primary heat exchanger 200; the first condenser 400 is connected to the secondary heat exchanger 300; the tower top reflux pump 500 is connected to the first condenser 400 The top reflux pump 500 is connected to the top of the trioxymethylene reboiling tower 100; the gaseous medium produced at the top of the trioxymethylene reboiling tower 100 enters the condensate receiving tank of the first condenser 400 through the primary heat exchanger 200 and the secondary heat exchanger 300. In this embodiment, the bottom of the methanol recovery tower 700 is connected to the bottom reboiler 600 of the recovery tower; the bottom reboiler 600 of the recovery tower connected to the bottom of the methanol recovery tower 700 is connected to the top of the trioxymethylene reboiling tower 100; the second condenser 800 is connected to the bottom reboiler 600 of the recovery tower, and the second condenser 800 is connected to the secondary heat exchanger 300.
[0029] During the production process, the top of the trioxymethylene reboiling tower 100 will produce trioxymethylene gas accompanied by a large amount of heat. The trioxymethylene gas enters the bottom reboiler 600 of the recovery tower from the top of the trioxymethylene reboiling tower 100, and exchanges heat with the material flowing out from the bottom of the methanol recovery tower 700 to utilize the heat accompanying the trioxymethylene gas, and provide the heat of trioxymethylene to the bottom reboiler 600 of the recovery tower, thereby achieving the effect of improving the energy recovery rate. The trioxymethylene gas passing through the bottom reboiler 600 of the recovery tower enters the condensate receiving tank of the second condenser 800, is pumped to the secondary heat exchanger 300 for cooling, and finally converges to the condensate receiving tank of the first condenser 400.
[0030] The above-mentioned polyoxymethylene process energy recovery and utilization system adds a pipeline to the gas phase pipeline from the polyoxymethylene reboiling tower 100 to the primary heat exchanger 200, so that a large amount of heat brought by the polyoxymethylene is transported to the recovery tower bottom reboiler 600 at the bottom of the methanol recovery tower 700. This process can simultaneously reduce the energy consumption of the primary heat exchanger 200 and the recovery tower bottom reboiler 600, so as to achieve the purpose of improving the energy recovery and utilization rate, thereby reducing production costs.
[0031] In one embodiment, a circulating pump 810 is provided on the pipeline between the second condenser 800 and the secondary heat exchanger 300. The circulating pump 810 is used to pump the material entering the second condenser 800 and completing condensation to the upstream secondary heat exchanger 300 through the pipeline, and then returns to the process from the secondary heat exchanger 300 to the first condenser 400.
[0032] In one embodiment, the top of the trioxymethylene reboiling tower 100 is connected to the primary heat exchanger 200 via a top discharge line 110 .
[0033] In one embodiment, a first valve 111 is disposed on the tower top discharge pipeline 110 .
[0034] In one embodiment, the top of the trioxymethylene reboiling tower 100 is connected to the bottom reboiler 600 of the recovery tower through an energy recovery pipeline 120. It should be noted that the energy recovery pipeline 120 needs to be insulated to ensure that a large amount of heat is not lost. Further, in one embodiment, an insulation tape is wrapped around the outer wall of the energy recovery pipeline 120 to further improve energy utilization.
[0035] In one embodiment, a second valve 121 is provided on the energy recovery line 120. Thus, the second valve 121 can be used to cut off or open the newly added process from the top of the trioxymethylene reboiling tower 100 to the reboiler 600 at the bottom of the recovery tower, further improving the flexibility of the system and being able to adapt to more working conditions.
[0036] In one embodiment, the energy recovery line 120 meets the tower top discharge line 110 upstream of the first valve 111 .
[0037] In one embodiment, the top reflux pump 500 is connected to the top of the trioxymethylene reboiling column 100 via a reflux line 510 .
[0038] In one embodiment, the return line 510 is provided with a third valve 511 .
[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.
[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.
[0041] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0042] In the present utility model, unless otherwise clearly specified and limited, the first feature "above" or "below" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature may be that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. It should be noted that when an element is referred to as "fixed to" or "set on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.
Claims
1. A polyoxymethylene process energy recovery and utilization system, characterized in that: include Trioxymethylene reboiling tower; A primary heat exchanger connected to the top of the trioxymethylene reboiling tower; A secondary heat exchanger connected to the primary heat exchanger; A first condenser connected to the secondary heat exchanger; A tower top reflux pump connected to the first condenser, wherein the tower top reflux pump is connected to the top of the trioxymethylene reboiling tower; A reboiler at the bottom of the recovery tower is connected to the top of the trioxymethylene reboiling tower; A methanol recovery tower, the bottom of which is connected to a reboiler at the bottom of the recovery tower; The second condenser is connected to the reboiler at the bottom of the recovery tower, and the second condenser is connected to the secondary heat exchanger.
2. The polyoxymethylene process energy recovery and utilization system according to claim 1, characterized in that: A circulation pump is arranged on the pipeline between the second condenser and the secondary heat exchanger.
3. A polyoxymethylene process energy recovery and utilization system according to claim 1 or 2, characterized in that: The top of the trioxymethylene reboiling tower is connected to the primary heat exchanger through a top discharge pipeline.
4. The polyoxymethylene process energy recovery and utilization system according to claim 3, characterized in that: The tower top discharge pipeline is provided with a first valve.
5. The polyoxymethylene process energy recovery and utilization system according to claim 4, characterized in that: The top of the trioxymethylene reboiling tower is connected to the bottom reboiler of the recovery tower through an energy recovery pipeline.
6. The polyoxymethylene process energy recovery and utilization system according to claim 5, characterized in that: A thermal insulation tape is wound around the outer wall of the energy recovery pipeline.
7. The polyoxymethylene process energy recovery and utilization system according to claim 5, characterized in that: The energy recovery pipeline is provided with a second valve.
8. The polyoxymethylene process energy recovery and utilization system according to claim 7, characterized in that: The energy recovery pipeline meets the tower top discharge pipeline upstream of the first valve.
9. A polyoxymethylene process energy recovery and utilization system according to claim 1 or 2, characterized in that: The tower top reflux pump is connected to the tower top of the trioxymethylene reboiling tower through a reflux pipeline.
10. The polyoxymethylene process energy recovery and utilization system according to claim 9, characterized in that: The reflux line is provided with a third valve.