Trioxymethylene preparation device

Abstract

The utility model relates to the technical field of chemical production, in particular to a trioxymethylene preparation device, which comprises a trioxymethylene synthesis kettle, a rectifying tower and an evaporator, the top of the trioxymethylene synthesis kettle is directly connected with the rectifying tower, the bottom of the trioxymethylene synthesis kettle is directly connected with the evaporator, and the evaporator is connected with the rectifying tower. A reaction liquid outlet of the trioxymethylene synthesis kettle is communicated with a liquid inlet of the evaporator through a circulating pump. The trioxymethylene preparation device disclosed by the utility model is directly communicated with the rectifying tower and the evaporator, so that interactive mixing of reaction substances is enhanced, and meanwhile, reaction products can be quickly separated from a reaction system. Compared with a traditional mode that the trioxymethylene synthesis kettle and the rectifying tower are connected through a pipeline, the design is simplified, the investment is reduced, and the production efficiency is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical production, in particular to a trioxymethylene production device. Background Art

[0002] Trioxane, also known as trioxane, trimethaldehyde, and 1,3,5-trioxane, is an organic compound with the chemical formula C3H6O3. It is primarily used as an intermediate for the engineering plastic polyoxymethylene and other chemicals. It can also be used as a disinfectant and a colorless, flameless fuel. Trioxane is typically synthesized using high-concentration formaldehyde as a raw material in the presence of an acidic catalyst. However, existing trioxane production processes suffer from complex equipment and processes, low formaldehyde conversion rates, high energy consumption, numerous byproducts, and low purity of the resulting trioxane.

[0003] It can be seen from this that whether it is possible to provide a trioxymethylene preparation device based on the deficiencies in the existing technology, which has a more streamlined structural design, reduces the investment cost of the production device, and produces trioxymethylene with high purity, has become a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0004] The present embodiment provides a trioxymethylene preparation device, which simplifies the device structure, reduces the investment cost of the production device, improves the trioxymethylene preparation efficiency, and increases the reaction speed. The technical solution includes the following contents:

[0005] A trioxymethylene preparation device comprises a trioxymethylene synthesis kettle, a distillation tower and an evaporator. The top of the trioxymethylene synthesis kettle is directly connected to the distillation tower.

[0006] Furthermore, the bottom of the trioxymethylene synthesis kettle is directly connected to the evaporator.

[0007] Furthermore, the reaction liquid outlet of the trioxymethylene synthesis kettle is connected to the liquid inlet of the evaporator through a circulation pump.

[0008] Furthermore, the azeotrope outlet of the distillation tower is connected to the extraction tower.

[0009] Furthermore, the gas outlet of the extraction tower is connected to a desolventizing tower.

[0010] Furthermore, the liquid outlet of the desolventizing tower is connected to a light boiling point removal tower.

[0011] Furthermore, an impurity outlet is provided at the top of the light-boiling-product removal tower, the liquid outlet of the light-boiling-product removal tower is connected to the heavy-boiling-product removal tower, and a trioxymethylene outlet is provided on the heavy-boiling-product removal tower.

[0012] Furthermore, a waste liquid outlet is provided at the bottom of the trioxymethylene synthesis reactor 1 .

[0013] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0014] 1. The trioxymethylene production device of the present invention directly connects the steam outlet at the top of the trioxymethylene synthesis reactor to a distillation tower, and the bottom opening to an evaporator. This direct connection enhances the cross-mixing of reactants and facilitates the rapid separation of reaction products from the reaction system. Compared to the traditional method of connecting the trioxymethylene synthesis reactor and distillation tower via pipes, the design is streamlined and the investment is reduced.

[0015] 2. The trioxymethylene preparation device of the present invention is directly connected to an evaporator at the bottom of the trioxymethylene synthesis kettle. The reaction liquid enters the evaporator through a circulation pump, so that the gas evaporated from the reaction liquid passes into the interior of the trioxymethylene synthesis kettle from the bottom, thereby strengthening the turbulent state of the reaction system, not only accelerating the separation of the product from the reaction system, but also increasing the reaction speed.

[0016] 3. In the trioxymethylene production apparatus of this invention, the liquid outlet of the trioxymethylene synthesis kettle and the liquid inlet of the evaporator are connected via a circulating pump. The circulating pump circulates a reaction liquid that is 3 to 4 times the liquid holding capacity within the trioxymethylene synthesis kettle. This accelerates the reaction liquid's entry into the evaporator, improving its evaporation rate and flushing the evaporator's tubes, preventing the accumulation of paraformaldehyde scale on the inner walls of the evaporator tubes, which affects reaction efficiency. This design breaks away from the traditional thermosiphon design, reducing the evaporator's heat exchange area while improving heat exchange efficiency.

[0017] 4. The trioxymethylene production device of this utility model utilizes a directly connected distillation tower, trioxymethylene synthesis kettle, and evaporator. Furthermore, the extraction tower, desolventizing tower, light-boiling-product removal tower, and heavy-boiling-product removal tower are sequentially connected to the steam outlet of the distillation tower. This ensures that the trioxymethylene distilled from the top of the heavy-boiling-product removal tower has a purity of up to 99.9%. This streamlines the design of the device while significantly improving trioxymethylene production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the trioxymethylene preparation device in the embodiment of this application.

[0019] The accompanying drawings are numbered as follows: 1. Trioxymethylene synthesis kettle; 2. Evaporator; 3. Distillation tower; 4. Extraction tower; 5. Desolventizing tower; 6. Light boiling product removal tower; 7. Heavy boiling product removal tower; 8. Circulation pump. DETAILED DESCRIPTION

[0020] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0022] It should be noted that similar numbers and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures. In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the utility model product is usually placed when in use. They are only for the convenience of describing the utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limiting the utility model. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0023] Furthermore, terms such as "horizontal," "vertical," and "overhanging" do not necessarily imply that a component must be absolutely horizontal or overhanging, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," not that the structure must be perfectly horizontal, but rather that it can be slightly tilted.

[0024] In the description of the present invention, it should also be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0025] The following embodiments of the present invention are described in detail with reference to the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments may be combined with each other.

[0026] Example 1:

[0027] A trioxymethylene production apparatus comprises a trioxymethylene synthesis reactor 1, a distillation tower 3, and an evaporator 2. The trioxymethylene synthesis reactor 1 is provided with a reaction liquid inlet and a liquid outlet. The trioxymethylene synthesis reactor 1 is used to polymerize formaldehyde to produce trioxymethylene. The top of the trioxymethylene synthesis reactor 1 is directly connected to the distillation tower 3, and the bottom of the trioxymethylene synthesis reactor 1 is directly connected to the evaporator 2. This direct connection enhances the cross-mixing of the reactants and facilitates the rapid separation of the reaction products from the reaction system. Compared to the traditional method of connecting the trioxymethylene synthesis reactor 1 and the distillation tower 3 via pipelines, the design is simplified and the investment is reduced. The liquid outlet of the triformaldehyde synthesis reactor 1 and the liquid inlet of the evaporator 2 are connected via a circulation pump 8. Because the evaporator 2 is directly connected to the bottom of the triformaldehyde synthesis reactor 1, the reaction liquid in the triformaldehyde synthesis reactor 1 enters the evaporator 2 through the circulation pump 8. The gas evaporated from the evaporator 2 is then passed into the interior of the triformaldehyde synthesis reactor 1 from the bottom, enhancing the turbulent state of the reaction system, not only accelerating the product's escape from the reaction system but also increasing the reaction rate. The circulation pump 8 circulates 3-4 times the liquid holding capacity of the triformaldehyde synthesis reactor 1. By accelerating the reaction liquid's entry into the evaporator 2, the evaporation rate of the reaction liquid is increased, and the evaporator 2's tubes are flushed, preventing the accumulation of paraformaldehyde scale on the inner walls of the evaporator 2, which affects reaction efficiency. This design breaks away from the traditional thermosiphon design, reducing the heat exchange area of ​​the evaporator 2 while improving heat exchange efficiency.

[0028] A method for preparing trioxymethylene includes: feeding formaldehyde in an aqueous phase having a concentration of approximately 70% by weight as a raw material from a reaction liquid inlet to a trioxymethylene synthesis reactor 1, and introducing an acidic catalyst, such as liquid sulfuric acid or sulfonic acid resin sulfuric acid at a concentration of 0.1% to 1.5% by weight, into the reactor to cause the formaldehyde to undergo a polymerization reaction to produce trioxymethylene. A circulating pump 8 is set with an hourly circulation rate of three times the liquid holding capacity of the trioxymethylene synthesis reactor 1. Under the action of the circulating pump 8, the reacted liquid is continuously circulated from the liquid outlet of the trioxymethylene synthesis reactor 1 to an evaporator 2. The evaporator 2 contains trioxymethylene, formaldehyde, water, and some byproducts. The evaporator 2 evaporates the liquid and enters the trioxymethylene synthesis reactor 1 from the steam outlet. The liquid then enters a distillation tower 3 for distillation to produce an azeotrope containing trioxymethylene and water. Unreacted formaldehyde falls back into the trioxymethylene synthesis reactor 1 and continues to react. The bottom of the trioxymethylene synthesis reactor 1 is also provided with a waste liquid outlet, which needs to be drained regularly to reduce the concentration of unwanted by-products, such as formic acid, formaldehyde oligomers, and the like.

[0029] Example 2:

[0030] Based on the technical solution of Example 1, the azeotrope outlet of the distillation tower 3 is connected to an extraction tower 4. The gas outlet of the extraction tower 4 is connected to a desolventizing tower 5. The liquid outlet of the desolventizing tower 5 is connected to a light-boiler removal tower 6. The top of the light-boiler removal tower 6 is provided with an impurity outlet, and the liquid outlet of the light-boiler removal tower 6 is connected to a heavy-boiler removal tower 7, which is provided with a trioxymethylene outlet.

[0031] A method for preparing trioxymethylene: Based on the preparation method described in Example 1, the azeotrope of trioxymethylene and water is distilled from the top vapor outlet of the distillation tower 3 and transported via a pipeline to an extraction tower 4. Most of the azeotrope is extracted by a solvent and then transported via a pipeline from the top gas outlet of the extraction tower 4 to a solvent tower. The solvent tower is used to remove the extractant. The crude trioxymethylene solution from which the extractant has been removed is transported via a pipeline from the bottom liquid outlet of the solvent tower to a light-boiling-product removal tower 6. In the light-boiling-product removal tower 6, the light-boiling-products are concentrated to obtain trioxymethylene with a purity of 99.8%. The solution is then transported via a pipeline from the bottom liquid outlet to a heavy-boiling-product removal tower 7. Light waste impurities in the light-boiling-product removal tower 6 are discharged via the top impurity outlet. In the heavy-boiling-product removal tower 7, the trioxymethylene is further reboiled, and after removing heavy waste, a trioxymethylene product with a purity of 99.9% is distilled from the top, which can be used for downstream production of polyoxymethylene.

[0032] The trioxymethylene production device of the utility model utilizes a directly connected distillation tower 3, a trioxymethylene synthesis reactor 1, and an evaporator 2, as well as an extraction tower 4, a desolventizing tower 5, a light-boiling-product removal tower 6, and a heavy-boiling-product removal tower 7, all of which are sequentially connected to the steam outlet of the distillation tower 3. This ensures that the trioxymethylene distilled from the top of the heavy-boiling-product removal tower 7 has a purity of up to 99.9%. While streamlining the design of the device, the efficiency of trioxymethylene production is significantly improved.

[0033] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0034] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A trioxymethylene preparation device, characterized in that: The invention comprises a trioxymethylene synthesis kettle, a distillation tower and an evaporator, and is characterized in that the top of the trioxymethylene synthesis kettle is directly connected to the distillation tower, and the bottom of the trioxymethylene synthesis kettle is directly connected to the evaporator.

2. The trioxymethylene production device according to claim 1, characterized in that: The reaction liquid outlet of the trioxymethylene synthesis kettle is connected to the liquid inlet of the evaporator through a circulation pump.

3. The trioxymethylene production device according to any one of claims 1 to 2, characterized in that: The azeotrope outlet of the distillation tower is connected to the extraction tower.

4. The trioxymethylene production device according to claim 3, characterized in that: The gas outlet of the extraction tower is connected to the desolventizing tower.

5. The trioxymethylene production device according to claim 4, characterized in that: The liquid outlet of the desolventizing tower is connected to a light boiling substance removal tower.

6. The trioxymethylene production device according to claim 5, characterized in that: An impurity outlet is provided on the top of the light-boiling-substance removal tower. The liquid outlet of the light-boiling-substance removal tower is connected to the heavy-boiling-substance removal tower. A trioxymethylene outlet is provided on the heavy-boiling-substance removal tower.

7. The trioxymethylene production device according to claim 1, characterized in that: A waste liquid outlet is provided at the bottom of the trioxymethylene synthesis kettle.

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