Butadiene purification system and method for controlling content of propyne in propyne tower

Abstract

The invention belongs to the field of chemical engineering, and particularly relates to purification of butadiene, in particular to a butadiene purification system and a control method for the content of propyne in a propyne tower. According to the butadiene purification system disclosed by the invention, the propyne recovery system is arranged, so that recycling of propyne is realized, and environmental pollution is reduced. The invention further provides a method for controlling the content of the propyne in the propyne tower, whether the propyne in the propyne tower is discharged or not is controlled according to the pressure and / or temperature of the top end of the propyne tower, and the yield and purification efficiency of 1, 3-butadiene are balanced.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry, and specifically relates to the purification of butadiene, and in particular to a butadiene purification system and a method for controlling the propyne content in a propyne tower. Background Art

[0002] Butadiene is an organic compound with the chemical formula C4H6. It is a colorless gas with a slight aromatic odor. It is insoluble in water but soluble in most organic solvents such as acetone, benzene, acetic acid, esters, etc. It is a raw material for manufacturing synthetic rubber, synthetic resin, nylon, etc.

[0003] In the process of purifying 1,3-butadiene, 1,2-butadiene, propyne, and some C5 hydrocarbons, which have a large difference in boiling point from 1,3-butadiene, need to be separated. In the prior art, propyne is separated in a propyne tower. However, propyne is directly discharged into the atmosphere from the propyne tower, which will cause waste of propyne and pollution of the atmosphere. Summary of the invention

[0004] In order to solve the problems and shortcomings in the prior art, the present invention provides a butadiene purification system and a method for controlling the propyne content in a propyne tower. The present invention provides a 1,3-butadiene purification system, which realizes the recycling of propyne by setting a propyne recovery system and reduces the pollution to the environment. The butadiene purification system of the present invention includes a propyne tower and also includes: A reflux pipeline, wherein the reflux pipeline is at the top of the propyne tower, and one end of the reflux pipeline is connected to the propyne tower so that the propyne in the propyne tower flows from the propyne tower into the reflux pipeline; A propyne recovery system is connected to the other end of the reflux pipeline to collect propyne discharged from the propyne tower.

[0005] Optionally, the purification system further comprises: A carbon four tank, wherein the carbon four tank is connected to the propyne recovery system; A cooling device is provided between the propyne recovery system and the C4 tank.

[0006] Optionally, a monitoring device is provided at the top of the propyne tower, and the monitoring device is used to monitor the pressure and temperature at the top of the propyne tower.

[0007] Furthermore, the present invention provides a method for controlling the propyne content in a propyne tower, which is applicable to the butadiene purification system described in any one of the above items. The control method comprises: When the top temperature of the propyne tower is lower than the first preset temperature, or the top pressure of the propyne tower is higher than the first preset pressure, the top channel of the propyne tower is opened to discharge the propyne in the propyne tower from the propyne tower.

[0008] Optionally, the top channel of the propyne tower is in an open state, and when the top temperature of the propyne tower is greater than a second preset temperature, or the top pressure of the propyne tower is less than the second preset pressure, the top channel of the propyne tower is closed; The second preset temperature is greater than the first preset temperature; The second preset pressure is lower than the first preset pressure.

[0009] Optionally, the first preset temperature is 40°C; The first preset pressure is 0.48 MPa; The second preset temperature is 41°C; The second preset pressure is 0.46 MPa. Compared with the prior art, the present invention has the following beneficial effects: (1) By setting up a propyne recovery system, propyne can be recycled and utilized to reduce environmental pollution.

[0010] (2) Controlling whether propyne is discharged from the propyne tower based on the pressure and / or temperature at the top of the propyne tower to balance the recovery rate and purification efficiency of 1,3-butadiene. DETAILED DESCRIPTION

[0011] The following describes a method for controlling the propyne content in a butadiene purification system and a propyne tower according to an embodiment of the present invention. In the description of this embodiment, it should be understood that the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features, that is, include one or more of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. When a feature "includes or contains" one or some of the features it covers, unless otherwise specifically described, this indication does not exclude other features and may further include other features.

[0012] In the description of the present embodiment, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means 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 representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0013] In some embodiments of the butadiene purification system of the present invention, the purification system includes a propyne tower, a reflux line and a propyne recovery system. The reflux line is at the top of the propyne tower, and one end of the reflux line is connected to the propyne tower so that propyne in the propyne tower flows from the propyne tower into the reflux line. The propyne recovery system is connected to the other end of the reflux line to collect propyne discharged from the propyne tower.

[0014] Specifically, the butadiene purification system includes a propyne tower, a reflux pipeline and a propyne recovery system. One end of the reflux pipeline is connected to the inside of the propyne tower at the top of the propyne tower, and the other end of the reflux pipeline is connected to the propyne recovery system. The propyne gas in the propyne tower can enter the propyne recovery system through the reflux pipeline to realize the recovery of propyne.

[0015] In this embodiment, the propyne gas discharged from the top of the propyne tower enters the propyne recovery system, and the propyne recovery system collects the propyne, which can not only realize the reuse of propyne, but also avoid the propyne being discharged into the air to cause environmental pollution.

[0016] In some embodiments of the butadiene purification system of the present invention, the purification system further comprises a C4 tank and a cooling device. The C4 tank is connected to the propyne recovery system; and the cooling device is arranged between the propyne recovery system and the C4 tank.

[0017] That is to say, the propyne recovery system is connected to the C4 tank, and the gaseous propyne collected in the propyne recovery system releases heat and liquefies when passing through the cooling device, and the liquefied propyne enters the C4 tank.

[0018] In this embodiment, a cooling device is added to the flow channel from the propyne recovery system to the C4 tank, and the gaseous propyne is liquefied to release heat, and the heat is recovered by the cooling device. At the same time, the propyne is liquefied, the volume is reduced, and the mass of propyne contained in the C4 tank is increased.

[0019] In some embodiments of the butadiene purification system of the present invention, a monitoring device is provided at the top of the propyne tower, and the monitoring device is used to monitor the pressure and temperature at the top of the propyne tower.

[0020] In this embodiment, a detection device is installed on the top of the propyne tower to detect the pressure and temperature of the top of the propyne tower, so that the temperature and pressure of the top of the propyne tower can be visualized, thereby facilitating operators to perform corresponding operations based on the monitored data.

[0021] Furthermore, the present invention also provides a method for controlling the propyne content in a propyne tower, which is applicable to the butadiene purification system described in any of the above items. The control method comprises: When the top temperature of the propyne tower is lower than the first preset temperature, or the top pressure of the propyne tower is higher than the first preset pressure, the top channel of the propyne tower is opened to discharge the propyne in the propyne tower from the propyne tower.

[0022] Specifically, during the conventional production process, the top of the propyne tower is in a closed state. That is, the flow path for propyne and other gases in the propyne tower to enter the propyne recovery system is closed. When the temperature at the top of the propyne tower is lower than the first preset temperature, or the pressure at the top of the propyne tower is higher than the first preset pressure, the top channel of the propyne tower is opened, so that propyne and other gases in the propyne tower can flow out from the top of the tower and enter the propyne recovery system.

[0023] In this embodiment, when the temperature at the top of the propyne tower is lower than the first preset temperature, or the pressure at the top of the propyne tower is higher than the first preset pressure, the top channel of the propyne tower is opened to avoid excessive propyne gas content in the propyne tower, thereby affecting the separation and purification effect of 1,3-butadiene.

[0024] In some embodiments of the method for controlling the propyne content in the propyne tower of the present invention, the top channel of the propyne tower is in an open state, and when the top temperature of the propyne tower is greater than a second preset temperature, or the top pressure of the propyne tower is less than the second preset pressure, the top channel of the propyne tower is closed. The second preset temperature is greater than the first preset temperature; the second preset pressure is less than the first preset pressure.

[0025] In this embodiment, under the premise that the flow paths of the propyne tower and the propyne recovery system are unobstructed, when the temperature at the top of the propyne tower is greater than the second preset temperature, or the pressure at the top of the propyne tower is less than the second preset pressure, the top channel of the propyne tower is closed, so that the propyne and other gases in the propyne tower cannot flow out of the propyne tower. In other words, the propyne gas in the propyne tower is allowed to stay in the propyne tower.

[0026] When the gaseous propyne in the propyne tower is discharged to the outside, it will carry part of 1,3-butadiene. In this embodiment, when the temperature at the top of the propyne tower is greater than the second preset temperature, or the pressure at the top of the propyne tower is less than the second preset pressure, the top channel of the propyne tower is closed to avoid excessive loss of 1,3-butadiene, thereby improving the yield of 1,3-butadiene.

[0027] In some embodiments of the method for controlling the propyne content in a propyne tower of the present invention, the first preset temperature is 40° C., the first preset pressure is 0.48 MPa, the second preset temperature is 41° C., and the second preset pressure is 0.46 MPa.

[0028] In this embodiment, the first preset temperature, the second preset temperature, the first preset pressure, and the second preset pressure are set so that the purity and yield of 1,3-butadiene are at a balanced position, enabling the purification system to perform continuous production.

[0029] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A butadiene purification system, comprising a propyne tower, characterized in that: include: A reflux pipeline, wherein the reflux pipeline is at the top of the propyne tower, and one end of the reflux pipeline is connected to the propyne tower so that the propyne in the propyne tower flows from the propyne tower into the reflux pipeline; A propyne recovery system is connected to the other end of the reflux pipeline to collect propyne discharged from the propyne tower.

2. The purification system according to claim 1, characterized in that Also includes: A carbon four tank, wherein the carbon four tank is connected to the propyne recovery system; A cooling device is provided between the propyne recovery system and the C4 tank.

3. The purification system according to claim 1, characterized in that: A monitoring device is arranged at the top of the propyne tower, and the monitoring device is used to monitor the pressure and temperature at the top of the propyne tower.

4. A method for controlling the propyne content in a propyne tower, applicable to the butadiene purification system described in any one of claims 1 to 3, characterized in that: The control method comprises: When the top temperature of the propyne tower is lower than the first preset temperature, or the top pressure of the propyne tower is higher than the first preset pressure, the top channel of the propyne tower is opened to discharge the propyne in the propyne tower from the propyne tower.

5. The control method according to claim 4, characterized in that: The top channel of the propyne tower is in an open state, and when the top temperature of the propyne tower is greater than a second preset temperature, or the top pressure of the propyne tower is less than the second preset pressure, the top channel of the propyne tower is closed; The second preset temperature is greater than the first preset temperature; The second preset pressure is lower than the first preset pressure.

6. The control method according to claim 5, characterized in that: The first preset temperature is 40°C; The first preset pressure is 0.48 MPa; The second preset temperature is 41°C; The second preset pressure is 0.46 MPa.