Nitric acid feeding line and dimethyl oxalate production equipment

Abstract

The utility model relates to the field of a dimethyl oxalate synthesis process, in particular to a nitric acid feeding line and dimethyl oxalate production equipment, an original nitric acid liquid inlet subline is cancelled, and a nitric acid boundary valve is arranged at the output end of a nitric acid feeding system to control the flow of nitric acid entering a specific area or system, so that the nitric acid is ensured to flow in a specified range; it is ensured that nitric acid can stably and continuously enter the next link through a nitric acid feeding valve; through the arrangement of the nitric acid drainage regulating valve and the check valve behind the nitric acid feeding valve, after nitric acid supplementing is stopped, the nitric acid in the pipeline is released through the nitric acid drainage regulating valve, nitric acid accumulated liquid stored in the pipeline is avoided, and therefore the situation that the nitric acid flows backwards and reacts with liquid stored in the pipeline is doubly avoided; and the safety of the pipeline is further improved. The problem that the accident risk is high due to the fact that nitric acid feed of an existing nitric acid reduction tower accumulates in a pipeline and reacts with alcohol-containing liquid of a methyl nitrite regeneration tower reversely into the nitric acid pipeline is solved.

Description

Technical Field

[0001] This utility model relates to the technical field of dimethyl oxalate synthesis process, specifically to a nitric acid feed line and dimethyl oxalate production equipment. Background Technology

[0002] Dimethyl oxalate, also known as dimethyl oxalate, is an important intermediate in the manufacture of dyes, resins, plastics, and pharmaceuticals, and is widely used in various fields such as chemical engineering, materials science, pharmaceuticals, agriculture, and manufacturing. Currently, the global dimethyl oxalate market is quite large, mainly concentrated in Asia. Its production process involves an esterification reaction of an alcoholic solution with nitric oxide and nitric acid to produce methyl nitrite; then, methyl nitrite is carbonylated with carbon monoxide to produce dimethyl oxalate. In the synthesis of dimethyl oxalate, nitric acid plays a crucial role as a nitrogen source.

[0003] The existing nitric acid reduction tower has a nitric acid pipeline and a bypass line at the feed end. When the nitric acid supply stops, nitric acid easily accumulates in the nitric acid pipeline and bypass line. Due to changes in the internal pressure of the system, the alcohol-containing liquid in the MN regeneration tower may backflow into the nitric acid pipeline and react with the accumulated nitric acid to produce methyl nitrate. The reaction principle is: CH3OH + HNO3 = CH3ONO2 + H2O. This reaction releases a large amount of heat, which can lead to accidents and greatly increase the risk of explosion. Utility Model Content

[0004] In view of the high risk of accidents caused by the accumulation of nitric acid feed in the pipeline of the nitric acid reduction tower and the backflow of alcohol-containing liquid from the methyl nitrite (MN) regeneration tower into the nitric acid pipeline, this utility model provides a nitric acid feed line and dimethyl oxalate production equipment.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This utility model provides a nitric acid feed line, including a nitric acid feeding system. The output end of the nitric acid feeding system is sequentially connected to a nitric acid boundary valve, a nitric acid feed valve, a nitric acid discharge regulating valve, a check valve, and a mixer. The output end of the mixer is connected to a nitric acid reduction tower. The nitric acid discharge regulating valve is connected to a first drain valve.

[0007] Optionally, a nitric acid flow meter is installed between the nitric acid boundary valve and the nitric acid feed valve.

[0008] Optionally, a second drain valve is provided between the nitric acid flow meter and the nitric acid feed valve.

[0009] Optionally, a first manual valve is provided between the nitric acid discharge regulating valve and the check valve.

[0010] Optionally, a shut-off valve is provided between the first hand valve and the check valve.

[0011] Optionally, a second hand valve is provided between the mixer and the nitric acid reduction tower.

[0012] This utility model provides a dimethyl oxalate production equipment, including an alcohol feeding system, a demineralized water feeding system, and the aforementioned nitric acid feed line; the alcohol feeding system is connected to an alcohol feed regulating valve; the demineralized water feeding system is connected to a demineralized water regulating valve; both the alcohol feed regulating valve and the demineralized water regulating valve are connected to a mixer.

[0013] Optionally, an alcohol flow meter is installed between the alcohol feed regulating valve and the alcohol feeding system.

[0014] Optionally, a third manual valve is provided between the alcohol flow meter and the alcohol feed regulating valve, and a third drain valve is provided between the third manual valve and the alcohol feed regulating valve.

[0015] Optionally, a fourth manual valve is provided between the alcohol feed regulating valve and the mixer.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This utility model provides a nitric acid feed line, including a nitric acid feeding system. The output end of the nitric acid feeding system is sequentially connected to a nitric acid boundary valve, a nitric acid feed valve, a nitric acid discharge regulating valve, a check valve, and a mixer. The output end of the mixer is connected to a nitric acid reduction tower. The nitric acid discharge regulating valve is connected to a first drain valve. For safety reasons, the original nitric acid feed line was eliminated, and a nitric acid boundary valve was installed at the output of the nitric acid feeding system to control the flow rate of nitric acid into a specific area or system, ensuring that the nitric acid flows within a specified range. The nitric acid feed valve controls the flow rate of nitric acid into subsequent processing stages, ensuring that the nitric acid can stably and continuously enter the next stage. By setting up a nitric acid drain regulating valve and a check valve after the nitric acid feed valve, the backflow of alcohol can be effectively prevented after the nitric acid supply stops. At the same time, the nitric acid drain regulating valve releases the nitric acid in the pipeline, avoiding the accumulation of nitric acid in the pipeline. This doubly prevents the backflow of alcohol and the reaction of the liquid in the pipeline, further improving the safety of the pipeline. The mixer is used to mix nitric acid and alcohol and introduce them into the nitric acid reduction tower for reaction. By connecting the first drain valve to the nitric acid drain regulating valve, the excess nitric acid in the pipeline can be released by the nitric acid drain regulating valve, avoiding the reaction with alcohol and the heat release that would affect the safety of the production line.

[0018] A nitric acid flow meter is installed between the nitric acid boundary valve and the nitric acid feed valve, which can accurately measure and monitor the flow changes of nitric acid in real time, ensuring that the supply of nitric acid matches the production demand. This helps to avoid nitric acid waste and shortage, and improves production efficiency and product quality.

[0019] A second drain valve is provided between the nitric acid flow meter and the nitric acid feed valve, which can release the residual liquid at the front end of the nitric acid feed valve after the nitric acid supply stops. At the same time, it provides convenience for the maintenance and calibration of the flow meter.

[0020] A first-hand valve is installed between the nitric acid discharge regulating valve and the check valve. This first-hand valve increases the safety of system operation. In emergencies, such as nitric acid leaks or pipeline ruptures, the flow of nitric acid can be quickly cut off by closing the first-hand valve, preventing further escalation. This helps protect the safety of production personnel and equipment, reducing the risk of accidents.

[0021] A shut-off valve is installed between the first manual valve and the check valve. After the nitric acid supply stops, the shut-off valve can quickly cut off the connection between the nitric acid pipeline and the mixer. In conjunction with the check valve, the effect of preventing backflow of alcohol is further improved, ensuring the safety of the production line.

[0022] A secondary valve is installed between the mixer and the nitric acid reduction tower. During maintenance and repair of the mixer or nitric acid reduction tower, the relevant part can be isolated from the entire system by closing the secondary valve, thus preventing nitric acid leakage or contamination during the maintenance process.

[0023] This invention also provides a dimethyl oxalate production device, including an alcohol feeding system, a demineralized water feeding system, and the aforementioned nitric acid feed line; the alcohol feeding system is connected to an alcohol feed regulating valve; the demineralized water feeding system is connected to a demineralized water regulating valve; both the alcohol feed regulating valve and the demineralized water regulating valve are connected to a mixer. The alcohol feeding system precisely controls the flow rate of the alcohol through the alcohol feed regulating valve, ensuring that the alcohol enters the mixer at an appropriate ratio and flow rate; the demineralized water feeding system can effectively reduce the desorption of MN in the alcohol. This equipment features high safety, high reliability, and ease of system maintenance and repair.

[0024] An alcohol flow meter is installed between the alcohol feed regulating valve and the alcohol feeding system. The flow meter can measure the alcohol flow rate in real time and accurately, providing precise data support for flow control during the production process. By monitoring the alcohol flow rate, operators can adjust the opening of the alcohol feed regulating valve in a timely manner to ensure that the alcohol enters the mixer at an appropriate flow rate, thereby optimizing chemical reaction conditions and improving the production efficiency and product quality of dimethyl oxalate.

[0025] A third hand valve is installed between the alcohol flow meter and the alcohol feed regulating valve, and a third drain valve is installed between the third hand valve and the alcohol feed regulating valve. The third hand valve allows for the rapid shut-off of alcohol flow in emergencies, preventing further escalation and helping to protect the safety of production personnel and equipment, thus reducing the risk of accidents. The combined use of the third hand valve and the third drain valve enables the system to be flexibly adjusted under different operating conditions.

[0026] A fourth hand valve is installed between the alcohol feed regulating valve and the mixer. This fourth hand valve is used to quickly close the flow of alcohol to the mixer in case of abnormal situations during production, such as alcohol leakage, mixer malfunction, or abnormal system pressure, thus protecting production and equipment safety. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a nitric acid feed line according to the present invention.

[0028] Figure 2 This is a structural diagram of the dimethyl oxalate production equipment of this utility model.

[0029] Among them, 1-nitric acid feeding system, 2-nitric acid boundary valve, 3-nitric acid feed valve, 4-nitric acid drain regulating valve, 5-check valve, 6-mixer, 7-nitric acid reduction tower, 8-first drain valve, 9-nitric acid flow meter, 10-second drain valve, 11-first manual valve, 12-shut-off valve, 13-second manual valve, 14-alcohol feeding system, 15-alcohol feed regulating valve, 16-alcohol flow meter, 17-third manual valve, 18-third drain valve, 19-fourth manual valve, 20-drain drain valve, 21-bypass manual valve, 22-demineralized water feeding system, 23-demineralized water regulating valve, 24-alcohol auxiliary feeding system. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] 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 merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] In the description of the embodiments of this utility model, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the utility model. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0034] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0035] In the description of the embodiments of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0036] The present invention will be further described in detail below with reference to specific embodiments. The description is for explanation and not limitation of the present invention.

[0037] See Figure 1 This utility model discloses a nitric acid feed line, including a nitric acid feeding system 1. The output end of the nitric acid feeding system 1 is sequentially connected to a nitric acid boundary valve 2, a nitric acid flow meter 9, a nitric acid feed valve 3, a nitric acid discharge regulating valve 4, a first manual valve 11, a shut-off valve 12, a check valve 5, and a mixer 6. The output end of the mixer 6 is connected to a nitric acid reduction tower 7. The nitric acid discharge regulating valve 4 is connected to a first drain valve 8. A second drain valve 10 is provided between the nitric acid flow meter 9 and the nitric acid feed valve 3. A second manual valve 13 is provided between the mixer 6 and the nitric acid reduction tower 7.

[0038] Nitric acid output from nitric acid feeding system 1 passes through nitric acid boundary valve 2, nitric acid flow meter 9, nitric acid feed valve 3, nitric acid drain regulating valve 4, first hand valve 11, shut-off valve 12, and check valve 5, and enters mixer 6 to mix with alcohol and be transported to nitric acid reduction tower 7 for reaction. When nitric acid replenishment stops, the presence of check valve 5 prevents alcohol from backflowing into the nitric acid feed line. Shut-off valve 12 further prevents alcohol from entering the nitric acid feed line. Finally, nitric acid drain regulating valve 4 and first drain valve 8 are opened to discharge residual liquid in the nitric acid feed line, further improving pipeline safety.

[0039] See Figure 2 This utility model also provides a dimethyl oxalate production equipment, including an alcohol feeding system 14, a demineralized water feeding system 22, an alcohol auxiliary feeding system 24, and the aforementioned nitric acid feed line; the alcohol feeding system 14 is sequentially connected to an alcohol flow meter 16, a third manual valve 17, a third drain valve 18, an alcohol feed regulating valve 15, and a fourth manual valve 19; the demineralized water feeding system 22 is connected to a demineralized water regulating valve 23; both the fourth manual valve 19 and the demineralized water regulating valve 23 are connected to a mixer 6; the alcohol auxiliary feeding system 24 is connected to a drain valve 20, which is connected between the alcohol feed regulating valve 15 and the fourth manual valve 19; a bypass manual valve 20 is provided outside the third manual valve 17 and the fourth manual valve 19 to facilitate the replacement and maintenance of the third manual valve 17, the third drain valve 18, the alcohol feed regulating valve 15, and the fourth manual valve 19. The equipment features high safety, high reliability, and ease of system maintenance and repair.

[0040] In summary, this utility model provides a nitric acid feed line and dimethyl oxalate production equipment. For safety reasons, the original nitric acid feed branch line is eliminated, and a nitric acid boundary valve 2 is installed at the output end of the nitric acid feed system 1 to control the flow rate of nitric acid into a specific area or system, ensuring that the nitric acid flows within a specified range. The nitric acid feed valve 3 controls the flow rate of nitric acid into the subsequent processing stage, ensuring that the nitric acid can stably and continuously enter the next stage. With the nitric acid discharge regulating valve 4 and check valve 5 installed after the nitric acid feed valve 3, the backflow of alcohol can be effectively prevented after the nitric acid supply stops. At the same time, the nitric acid in the pipeline is released through the nitric acid discharge regulating valve 4, avoiding the accumulation of nitric acid in the pipeline. This doubly prevents the backflow of alcohol and the reaction of the liquid in the pipeline, further improving the safety of the pipeline.

[0041] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the technical solution of the present utility model in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present utility model, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A nitric acid feed line, characterized in that, The system includes a nitric acid feeding system (1), the output of which is sequentially connected to a nitric acid boundary valve (2), a nitric acid feed valve (3), a nitric acid drain regulating valve (4), a check valve (5), and a mixer (6), the output of which is connected to a nitric acid reduction tower (7); the nitric acid drain regulating valve (4) is connected to a first drain valve (8).

2. The nitric acid feed line according to claim 1, characterized in that, A nitric acid flow meter (9) is installed between the nitric acid boundary valve (2) and the nitric acid feed valve (3).

3. The nitric acid feed line according to claim 2, characterized in that, A second drain valve (10) is provided between the nitric acid flow meter (9) and the nitric acid feed valve (3).

4. The nitric acid feed line according to claim 1, characterized in that, A first manual valve (11) is provided between the nitric acid discharge regulating valve (4) and the check valve (5).

5. The nitric acid feed line according to claim 4, characterized in that, A shut-off valve (12) is provided between the first hand valve (11) and the check valve (5).

6. The nitric acid feed line according to claim 1, characterized in that, A second hand valve (13) is provided between the mixer (6) and the nitric acid reduction tower (7).

7. A dimethyl oxalate production equipment, characterized in that, It includes an alcohol feed system (14), a demineralized water feed system (22), and a nitric acid feed line as described in any one of claims 1-6; the alcohol feed system (14) is connected to an alcohol feed regulating valve (15); the demineralized water feed system (22) is connected to a demineralized water regulating valve (23); both the alcohol feed regulating valve (15) and the demineralized water regulating valve (23) are connected to a mixer (6).

8. The dimethyl oxalate production equipment according to claim 7, characterized in that, An alcohol flow meter (16) is installed between the alcohol feed regulating valve (15) and the alcohol feeding system (14).

9. The dimethyl oxalate production equipment according to claim 8, characterized in that, A third manual valve (17) is provided between the alcohol flow meter (16) and the alcohol feed regulating valve (15), and a third drain valve (18) is provided between the third manual valve (17) and the alcohol feed regulating valve (15).

10. The dimethyl oxalate production equipment according to claim 7, characterized in that, A fourth manual valve (19) is provided between the alcohol feed regulating valve (15) and the mixer (6).

Images