Deoxidation polymerization inhibitor adding device for reflux tank of light component removal tower for preparing butadiene by acetonitrile method

Abstract

The utility model relates to the technical field of chemical production, and particularly discloses a deoxidation polymerization inhibitor adding device for a reflux tank of a light component removal tower for preparing butadiene by an acetonitrile method. The deoxidation polymerization inhibitor adding device comprises a polymerization inhibitor injection pipeline, a water injection pipeline, a heat exchanger, a reflux tank and a reflux pump; the deoxidation polymerization inhibitor adding device is matched with the light component removal tower; a top outlet of the light component removal tower is connected to the heat exchanger; a bottom outlet of the heat exchanger is connected to the top of a reflux tank through a liquid inlet connecting pipeline, a bottom outlet of the reflux tank is connected to a reflux pump, and the reflux pump is connected to the upper side wall of the light component removal tower through a pipeline. According to the device, the light component removal tower which does not have the deoxidation function originally has the deoxidation capacity, generation of butadiene peroxide and terminal polymers in the butadiene water washing tower can be effectively reduced and delayed by adding the polymerization inhibitor, the device can run better and more stably, economic losses caused by abnormal shutdown are reduced, and the service life of the device is prolonged. And the potential safety hazard of the device due to polymer generation is also reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical production, and specifically discloses a deoxidation inhibitor adding device for a reflux tank of a lightness removal tower for preparing butadiene by an acetonitrile process. Background Art

[0002] The butadiene unit adopts the acetonitrile method to produce butadiene. The function of the butadiene lightness removal tower is to remove propyne from the system. The medium in the butadiene lightness removal tower is butadiene with a purity greater than 99.5%. Butadiene contacts with oxygen to generate butadiene peroxide, which is further polymerized to generate extremely dangerous butadiene end polymers.

[0003] Butadiene is a conjugated diene with very active chemical properties. It will polymerize to form butadiene peroxide under aerobic conditions. The peroxide will further polymerize to form butadiene end polymers. The main inducing factors for the formation of polymers are oxygen, including air, rust, etc.

[0004] High-concentration butadiene reacts with oxygen within the equipment and pipelines, easily forming peroxide autopolymers and end-polymers. Peroxides are highly unstable and can rapidly decompose and explode upon impact or sudden heating. This can also trigger the polymerization of butadiene end groups, producing a white, honeycomb-like solid. The formation of butadiene end-polymers is a free radical chain growth process with high polymerization heat. Once polymerization occurs, the heat cannot be dissipated quickly, which in turn accelerates free radical generation and chain growth, accelerating polymerization and forming a vicious cycle that ultimately leads to explosive polymerization. The polymer particles continue to grow and extend outward until they fill the equipment. When butadiene end-polymers fill the equipment or form large aggregates, some of the active centers are shielded within the solid particles. While linear butadiene molecules can penetrate the macromolecular rings formed by polymerization and enter the solid interior, inhibitor molecules with macromolecular groups have difficulty entering the solid interior. Therefore, once the polymer is formed, the inhibitor's effectiveness is quite limited.

[0005] Therefore, strict requirements must be placed on the location and amount of polymerization inhibitors added to ensure that there is no oxygen in the device that can induce polymerization of butadiene, thereby preventing the generation of butadiene peroxides and end polymers.

[0006] Deoxidation inhibitors, such as sodium nitrite solution, are excellent scavengers, effectively consuming oxygen in the system and preventing butadiene from self-polymerization. The butadiene in the T-202 butadiene lightness removal tower is greater than 99.5% pure. High-purity butadiene, when exposed to oxygen within the tower, is susceptible to the formation of butadiene peroxides, which further polymerize into butadiene endpolymers.

[0007] Currently, the T-202 tower and reflux tank lack a deoxidation inhibitor addition point. Trace amounts of oxygen in the system accelerate the self-polymerization of high-purity butadiene, generating butadiene peroxides and, in turn, end-polymers. These can clog the tower trays, hindering gas-liquid mass transfer, and potentially rupture flanges and equipment, causing damage and butadiene leakage, ultimately leading to fire and explosion. Butadiene polymer particles gradually break apart into smaller particles due to expansion and internal molecular crosslinking, generating stronger expansion stress. As their volume increases, the expansion of end-polymers can easily cause equipment and pipeline ruptures, leading to leaks. Therefore, depleting oxygen within the T202 refining tower is highly effective in preventing butadiene polymerization. If polymer clogging the tower trays causes plant shutdown, significant economic losses and safety hazards can result.

[0008] Therefore, it is necessary to design a deoxidation inhibitor adding device for the reflux tank of the light removal tower for preparing butadiene by the acetonitrile method to ensure the normal operation of the system equipment and product production. Utility Model Content

[0009] The technical solutions adopted in this utility model are as follows:

[0010] A deoxidation inhibitor adding device for a reflux tank of a lightness removal tower for preparing butadiene by an acetonitrile process, comprising a polymerization inhibitor injection pipe 6, a water injection pipe 7, a heat exchanger 8, a reflux tank 9, and a reflux pump 10; the deoxidation inhibitor adding device is coordinated with a lightness removal tower 11;

[0011] The top outlet of the light removal tower 11 is connected to the heat exchanger 8; the bottom outlet of the heat exchanger 8 is connected to the top of the reflux tank 9 through the liquid inlet connecting pipe 5, and the bottom outlet of the reflux tank 9 is connected to the reflux pump 10, and the reflux pump 10 is connected to the upper side wall of the light removal tower 11 through a pipeline;

[0012] The outlet of the water injection pipe 7 is merged into the outlet of the polymerization inhibitor injection pipe 6, and the common outlet of the two pipes is connected to the middle section of the liquid inlet connecting pipe 5; a liquid inlet valve is provided before the common outlet of the two pipes is connected to the connection point of the liquid inlet connecting pipe 5;

[0013] The polymerization inhibitor injection pipe 6 is used to input polymerization inhibitor, and the water injection pipe 7 is used to input water.

[0014] Preferably, the liquid inlet valve includes a first valve 1 , an automatic regulating valve 2 and a second valve 3 connected in series, for regulating the input flow of the inhibitor injection pipeline 6 and the water injection pipeline 7 .

[0015] Furthermore, a bypass pipe is connected in parallel between the two ends of the first valve 1 and the second valve 3 , and a bypass valve 4 is provided on the bypass pipe for repairing the redundant valve provided in the automatic regulating valve 2 .

[0016] Preferably, the polymerization inhibitor input into the polymerization inhibitor injection pipe 6 is a 1% to 2% sodium nitrite solution.

[0017] Preferably, the water injection pipe 7 is provided with a water injection valve 13 before being merged into the outlet pipe of the polymerization inhibitor injection pipe 6 .

[0018] Preferably, a water separation funnel valve 14 is provided at the bottom of the reflux tank 9 for separating and discharging the sodium nitrite aqueous solution and butadiene.

[0019] Preferably, valves are provided on the liquid inlet connecting pipe 5 and the pipe connecting the top outlet of the lightness removal tower 11 to the heat exchanger 8.

[0020] Preferably, the bottom of the light-removal tower 11 is connected to the extraction tower via a pressure pump 12 .

[0021] The principle of this utility model is to connect a polymerization inhibitor injection pipe 6, containing a 1% to 2% sodium nitrite solution, to the top of a lightness removal tower 11, using a liquid inlet connecting pipe 5 for adding wash water. This allows the additive system to pass the 1% to 2% sodium nitrite solution into the top of the lightness removal tower 11 through a first valve 1, a regulating valve 2, and a second valve 3. The amount of the 1% to 2% sodium nitrite solution entering the lightness removal tower 11 is precisely adjusted by a pneumatic regulating valve 1, so that the oxygen in the T-301 tower is consumed by the 1% to 2% sodium nitrite solution. This depletion of oxygen within the tower eliminates the conditions for the formation of peroxides and end polymers, thereby ensuring smooth system operation and reducing unexpected shutdowns, minimizing economic losses and the potential safety hazards associated with butadiene polymers.

[0022] Beneficial effects achieved by this utility model:

[0023] The utility model discloses a deoxidation and polymerization inhibitor adding device for a reflux tank of a lightness removal tower for preparing butadiene by an acetonitrile process. By arranging an auxiliary agent adding system at a washing water inlet at the top of the tower, the lightness removal tower, which originally does not have a deoxidation function, is endowed with a deoxidation function. The addition of the polymerization inhibitor can effectively reduce and delay the generation of butadiene peroxides and terminal polymers in the butadiene water washing tower, thereby enabling the device to operate better and more stably, reducing economic losses caused by abnormal shutdowns, and also lowering the potential safety hazards of the device due to the generation of polymers. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the deoxidation inhibitor adding device for the reflux tank of the light removal tower for the preparation of butadiene by acetonitrile method DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention more clear and distinct, the present invention is further described in detail with reference to the following embodiments. It should be noted that the present invention is not limited to the following embodiments.

[0026] Example 1

[0027] A deoxidation inhibitor adding device for a reflux tank of a lightness removal tower for preparing butadiene by an acetonitrile process, comprising a polymerization inhibitor injection pipe 6, a water injection pipe 7, a heat exchanger 8, a reflux tank 9, and a reflux pump 10; the deoxidation inhibitor adding device is coordinated with a lightness removal tower 11;

[0028] The top outlet of the light removal tower 11 is connected to the heat exchanger 8; the bottom outlet of the heat exchanger 8 is connected to the top of the reflux tank 9 through the liquid inlet connecting pipe 5, and the bottom outlet of the reflux tank 9 is connected to the reflux pump 10, and the reflux pump 10 is connected to the upper side wall of the light removal tower 11 through a pipeline;

[0029] The outlet of the water injection pipe 7 is merged into the outlet of the polymerization inhibitor injection pipe 6, and the common outlet of the two pipes is connected to the middle section of the liquid inlet connecting pipe 5; a liquid inlet valve is provided before the common outlet of the two pipes is connected to the connection point of the liquid inlet connecting pipe 5;

[0030] The polymerization inhibitor injection pipe 6 is used to input polymerization inhibitor, and the water injection pipe 7 is used to input water.

[0031] Preferably, the liquid inlet valve includes a first valve 1, an automatic regulating valve 2 and a second valve 3 connected in series, which are used to adjust the input flow of the inhibitor injection pipe 6 and the water injection pipe 7. A bypass pipe is connected in parallel at both ends of the first valve 1 and the second valve 3. The bypass pipe is provided with a bypass valve 4 for repairing the redundant valve provided by the automatic regulating valve 2. The water injection pipe 7 is provided with a water injection valve 13 before the outlet pipe is incorporated into the inhibitor injection pipe 6. A water diversion funnel valve 14 is provided at the bottom of the reflux tank 9 for separating and discharging the sodium nitrite aqueous solution and butadiene. Valves are provided on the liquid inlet connecting pipe 5 and the pipe connecting the top outlet of the de-lightening tower 11 to the heat exchanger 8. The bottom of the de-lightening tower 11 is connected to the extraction tower through a pressure pump 12.

[0032] The polymerization inhibitor injected into the polymerization inhibitor injection pipe 6 is a 1% to 2% sodium nitrite solution.

[0033] Through the liquid inlet connecting pipe 5, which adds wash water to the top of the lightness removal tower 11, a polymerization inhibitor injection pipe 6, to which a 1% to 2% sodium nitrite solution is added, is connected to the liquid inlet connecting pipe 5. The auxiliary agent system then injects the 1% to 2% sodium nitrite solution into the top of the lightness removal tower 11 through a first valve 1, a regulating valve 2, and a second valve 3. The amount of the 1% to 2% sodium nitrite solution entering the lightness removal tower 11 is precisely adjusted by a pneumatic regulating valve 1, so that the oxygen in the T-301 tower is consumed by the 1% to 2% sodium nitrite solution. The loss of oxygen in the tower eliminates the conditions for the formation of peroxides and end polymers, thereby ensuring smooth system operation and reducing unexpected shutdowns, minimizing economic losses and safety hazards associated with butadiene polymers.

Claims

1. A deoxidation inhibitor adding device for the reflux tank of the light removal tower for preparing butadiene by acetonitrile process, characterized in that: It comprises a polymerization inhibitor injection pipe (6), a water injection pipe (7), a heat exchanger (8), a reflux tank (9) and a reflux pump (10); the deoxidation polymerization inhibitor adding device is coordinated with a light removal tower (11); The top outlet of the light-removal tower (11) is connected to the heat exchanger (8); the bottom outlet of the heat exchanger (8) is connected to the top of the reflux tank (9) through the liquid inlet connecting pipe (5); the bottom outlet of the reflux tank (9) is connected to the reflux pump (10), and the reflux pump (10) is connected to the upper side wall of the light-removal tower (11) through a pipe; The outlet of the water injection pipe (7) is merged into the outlet of the polymerization inhibitor injection pipe (6), and the common outlet of the two pipes is connected to the middle section of the liquid inlet connecting pipe (5); the common outlet of the two pipes is provided with a liquid inlet valve before the connection point to the liquid inlet connecting pipe (5); The polymerization inhibitor injection pipe (6) is used to input polymerization inhibitor, and the water injection pipe (7) is used to input water.

2. The deoxidation inhibitor adding device of the lightness removal tower reflux tank for preparing butadiene by acetonitrile method according to claim 1, characterized in that, The liquid inlet valve comprises a first valve (1), an automatic regulating valve (2) and a second valve (3) which are sequentially connected in series and are used to regulate the input flow of the polymerization inhibitor injection pipeline (6) and the water injection pipeline (7).

3. The deoxidation inhibitor adding device of the lightness removal tower reflux tank for preparing butadiene by acetonitrile method according to claim 2, characterized in that, A bypass pipeline is connected in parallel between the two ends of the first valve (1) and the second valve (3), and a bypass valve (4) is provided on the bypass pipeline for repairing the redundant valve provided on the automatic regulating valve (2).

4. The deoxidation inhibitor adding device of the lightness removal tower reflux tank for preparing butadiene by acetonitrile method according to claim 1, characterized in that, The polymerization inhibitor injected into the polymerization inhibitor injection pipe (6) is a 1% to 2% sodium nitrite solution.

5. The deoxidation inhibitor adding device of the lightness removal tower reflux tank for preparing butadiene by acetonitrile method according to claim 1, characterized in that, The water injection pipe (7) is provided with a water injection valve (13) before being merged into the outlet pipe of the polymerization inhibitor injection pipe (6).

6. The deoxidation inhibitor adding device of the lightness removal tower reflux tank for preparing butadiene by acetonitrile method according to claim 1, characterized in that, A water separation funnel valve (14) is provided at the bottom of the reflux tank (9) for separating and discharging the sodium nitrite aqueous solution and butadiene.

7. The deoxidation inhibitor adding device of the lightness removal tower reflux tank for preparing butadiene by acetonitrile method according to claim 1, characterized in that, Valves are provided on the liquid inlet connecting pipe (5) and the pipe connecting the top outlet of the light removal tower (11) to the heat exchanger (8).

8. The deoxidation inhibitor adding device of the lightness removal tower reflux tank for preparing butadiene by acetonitrile method according to claim 1, characterized in that, The bottom of the light removal tower (11) is connected to the extraction tower via a pressure pump (12).

Images