A propane dehydrogenation unit polypropylene offgas recovery system

Abstract

The utility model belongs to propane dehydrogenation equipment technical field, specifically discloses a kind of propane dehydrogenation device polypropylene tail gas recovery system, it includes: first conveying pipeline, second conveying pipeline, liquid separator, sewage treatment device;First conveying pipeline is used to transport the tail gas of polypropylene device, and second conveying pipeline is used to transport the product gas of product gas compressor;Liquid separator has conveying inlet, and liquid separator is provided with demister at conveying inlet;First conveying pipeline and second conveying pipeline are communicated with conveying inlet;The tail gas of polypropylene device is introduced into the conveying inlet of liquid separator by first conveying pipeline, then the product gas of product gas compressor of second conveying pipeline can be entered into liquid separator together, so that the propylene in the tail gas of polypropylene device, propane can be used as the raw material of propane dehydrogenation device to continue to use, to reach the effective recycling of propylene, propane, reduce the material consumption of propylene, propane, save production cost.

Description

Technical Field

[0001] This utility model relates to the technical field of propane dehydrogenation equipment, and in particular to a polypropylene tail gas recovery system for a propane dehydrogenation unit. Background Technology

[0002] Currently, a polypropylene unit can be installed downstream of a propane dehydrogenation unit. During the production process, the polypropylene unit generates tail gas, the main components of which are propylene, propane and ethylene. The polypropylene unit cannot recover this tail gas and can only discharge it into the flare system, resulting in a large amount of material loss. Utility Model Content

[0003] The purpose of this invention is to provide a polypropylene tail gas recovery system for a propane dehydrogenation unit, in order to solve the technical problem that the tail gas of the polypropylene unit in the prior art can only be discharged to the flare system, resulting in material loss.

[0004] To achieve the above objectives, this utility model provides a polypropylene tail gas recovery system for a propane dehydrogenation unit, comprising: a first conveying pipeline, a second conveying pipeline, a separating tank, and a wastewater treatment device; the first conveying pipeline is used to convey tail gas from the polypropylene unit, and the second conveying pipeline is used to convey product gas from the product gas compressor; the separating tank has a conveying inlet, and a demister is installed at the conveying inlet; the first and second conveying pipelines are connected to the conveying inlet; a gaseous component outlet is provided at the top of the separating tank; a liquid component outlet is provided at the bottom of the separating tank, and the liquid component outlet is connected to the wastewater treatment device through a third conveying pipeline.

[0005] Preferably, the first conveying pipeline is provided with a first regulating valve for adjusting the flow rate.

[0006] Preferably, the first conveying pipeline is further provided with a first switching valve and a second switching valve; the first regulating valve is provided on the pipeline between the first switching valve and the second switching valve.

[0007] Preferably, it further includes: a first parallel pipeline; the first parallel pipeline is connected in parallel with the first conveying pipeline; the first parallel pipeline is provided with a first ball valve.

[0008] Preferably, the third conveying pipeline is provided with a second regulating valve for adjusting the flow rate.

[0009] Preferably, the third conveying pipeline is further provided with a third switching valve and a fourth switching valve; the second regulating valve is disposed on the pipeline between the third switching valve and the fourth switching valve.

[0010] Preferably, it further includes: a second parallel pipeline; the second parallel pipeline is connected in parallel with the second conveying pipeline; the second parallel pipeline is equipped with a second ball valve.

[0011] Preferably, it further includes: a fourth conveying pipe; the fourth conveying pipe is connected to the outlet of the gaseous component.

[0012] The polypropylene tail gas recovery system for a propane dehydrogenation unit provided by this utility model has the following advantages: The first conveying pipe introduces the tail gas from the polypropylene unit into the inlet of the separator, where it enters the separator along with the product gas from the product gas compressor in the second conveying pipe. The separator separates the moisture and heavy hydrocarbons from the product gas and tail gas, allowing the propylene, propane, and ethylene in the product gas and tail gas to be transported from the gaseous component outlet to the product gas compressor of the propane dehydrogenation unit for three-stage compression, thereby achieving the recovery and utilization of the polypropylene unit's tail gas. Compared to directly discharging the tail gas from the polypropylene unit to the flare system, this embodiment allows for the effective recovery and utilization of propylene and propane in the tail gas, reducing the consumption of propylene and propane materials and saving production costs. Furthermore, the demister in the separator can filter out particulate impurities in the tail gas generated by the polypropylene unit, preventing these impurities from entering the product gas compressor of the propane dehydrogenation unit, thus ensuring the safe and stable operation of the product gas compressor and preventing any impact on the operation of the propane dehydrogenation unit.

[0013] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the pipeline connection structure of the polypropylene tail gas recovery system of the propane dehydrogenation device according to an embodiment of this utility model.

[0015] In the diagram, 100 is the first conveying pipeline; 110 is the first regulating valve; 120 is the first switching valve; 130 is the second switching valve; 200 is the second conveying pipeline; 300 is the separator; 310 is the conveying inlet; 320 is the gaseous component outlet; 330 is the liquid component outlet; 400 is the wastewater treatment device; 500 is the third conveying pipeline; 510 is the second regulating valve; 520 is the third switching valve; 530 is the fourth switching valve; 600 is the first parallel pipeline; 610 is the first ball valve; 700 is the second parallel pipeline; 710 is the second ball valve; and 800 is the fourth conveying pipeline. Detailed Implementation

[0016] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0017] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this utility model.

[0018] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0019] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0020] Please refer to the following: Figure 1 The polypropylene tail gas recovery system of the propane dehydrogenation device provided in this embodiment will now be described.

[0021] like Figure 1As shown in the figure, the polypropylene tail gas recovery system of the propane dehydrogenation unit according to this utility model includes: a first conveying pipeline 100, a second conveying pipeline 200, a separating tank 300, and a wastewater treatment device 400; the first conveying pipeline 100 is used to convey the tail gas of the polypropylene unit, and the second conveying pipeline 200 is used to convey the product gas of the product gas compressor; the separating tank 300 has a conveying inlet 310, and a demister is provided at the conveying inlet 310; the first conveying pipeline 100 and the second conveying pipeline 200 are connected to the conveying inlet 310; a gaseous component outlet 320 is provided at the top of the separating tank 300; a liquid component outlet 330 is provided at the bottom of the separating tank 300, and the liquid component outlet 330 is connected to the wastewater treatment device 400 through a third conveying pipeline 500. The gaseous component outlet 320 is used to connect to the product gas compressor of the propane dehydrogenation unit so that propylene and propane in the tail gas generated by the polypropylene unit can be conveyed to the propane dehydrogenation unit.

[0022] During the production process of the polypropylene unit, the first conveying pipeline 100 is used to transport the tail gas of the polypropylene unit. The main components of the tail gas are propylene, propane, and ethylene, which are similar to the product gas composition of the propane dehydrogenation unit. In this embodiment, the separator 300 is a three-stage separator 300 of the product gas compressor of the propane dehydrogenation unit, with an operating pressure of approximately 0.23 MPa. Therefore, the tail gas generated by the polypropylene unit can be transported to the separator 300 through the first conveying pipeline 100, so that the propylene and propane in the tail gas can be transported to the propane dehydrogenation unit to produce propane. Compared with directly discharging the tail gas of the polypropylene unit to the flare system, this embodiment can effectively recover and utilize the propylene in the tail gas, reduce propylene material consumption, and save production costs.

[0023] It should be noted that the three-stage separator 300 of the propane dehydrogenation unit is mainly used to separate moisture and heavy hydrocarbons from the product gas from the second-stage outlet and the tail gas from the polypropylene unit. Subsequently, propylene, propane, and ethylene in the gaseous product gas will be output from the gaseous component outlet 320 and sent to the product gas compressor of the propane dehydrogenation unit for three-stage compression. The moisture and heavy hydrocarbons at the bottom of the separator 300 will be discharged to the wastewater treatment unit 400 via the third conveying pipeline 500. The tail gas from the polypropylene unit contains a small amount of particulate impurities. After entering through the conveying inlet 310, the tail gas from the polypropylene unit passes through a demister. The demister filters out the particulate impurities in the tail gas from the polypropylene unit, thus achieving the function of cleaning particulate impurities from the polypropylene unit's tail gas and preventing particulate impurities from entering the product gas compressor of the propane dehydrogenation unit, thereby ensuring the safe and stable operation of the product gas compressor of the propane dehydrogenation unit.

[0024] In this embodiment, the first conveying pipe 100 introduces the tail gas from the polypropylene unit into the conveying inlet 310 of the separator 300. This allows it to enter the separator 300 along with the product gas from the product gas compressor in the second conveying pipe 200. The separator 300 separates moisture and heavy hydrocarbons from the product gas and tail gas, allowing propylene, propane, and ethylene from the gaseous component outlet to be conveyed to the product gas compressor of the propane dehydrogenation unit for three-stage compression. This achieves tail gas recovery and utilization from the polypropylene unit. Compared to directly discharging the tail gas from the polypropylene unit to the flare system, this embodiment allows for effective recovery and utilization of propylene and propane from the tail gas, reducing propylene and propane consumption and saving production costs. Furthermore, the demister in the separator 300 filters out particulate impurities from the tail gas generated by the polypropylene unit, preventing these impurities from entering the product gas compressor of the propane dehydrogenation unit. This ensures the safe and stable operation of the product gas compressor of the propane dehydrogenation unit and does not affect the operation of the propane dehydrogenation unit.

[0025] In some embodiments of this utility model, the first conveying pipeline 100 is provided with a first regulating valve 110 for adjusting the flow rate. The first regulating valve 110 is used to regulate the flow rate in the first conveying pipeline 100, that is, to regulate the flow rate of the tail gas of the polypropylene device entering the separator 300, thereby ensuring the normal operation of the separator 300 and avoiding the situation where the flow rate is too large and the separator 300 is overloaded.

[0026] In some embodiments of this utility model, the first conveying pipeline 100 is further provided with a first switching valve 120 and a second switching valve 130; the first regulating valve 110 is disposed on the pipeline between the first switching valve 120 and the second switching valve 130. The first switching valve 120 and the second switching valve 130 are shut-off valves, that is, installing shut-off valves before and after the first regulating valve 110 can prevent fluid backflow or pressure fluctuations from affecting the first regulating valve 110, ensuring the stable operation and precise control of the first regulating valve 110.

[0027] In some embodiments of this utility model, it further includes: a first parallel pipeline 600; the first parallel pipeline 600 is connected in parallel with the first conveying pipeline 100; the first parallel pipeline 600 is equipped with a first ball valve 610. When the first regulating valve 110 fails to work properly, the flow rate is temporarily controlled by manually operating the first ball valve 610 to ensure stable operation of the system under special working conditions. If the first regulating valve 110 malfunctions or needs maintenance, the first parallel pipeline 600 can serve as a backup channel to ensure that the system can continue to operate and avoid the entire system from shutting down due to a problem with the first regulating valve 110.

[0028] In some embodiments of this utility model, the third conveying pipe 500 is equipped with a second regulating valve 510 for adjusting the flow rate. The second regulating valve 510 is used to regulate the flow rate within the third conveying pipe 500, that is, to regulate the flow rate of the liquid components discharged from the separator 300 into the wastewater treatment device 400, thereby ensuring the normal operation of the wastewater treatment device 400 and avoiding excessive flow and overload operation of the wastewater treatment device 400. The liquid components output from the separator 300 mainly consist of moisture and heavy hydrocarbons in the product gas or tail gas, wherein the heavy hydrocarbons in the product gas or tail gas can be collected and treated by the wastewater treatment device 400. It is understood that the wastewater treatment device 400 can use physical treatment (grid filtration), chemical treatment (coagulant sedimentation), or biological treatment (biofilter decomposition) to remove heavy hydrocarbons, so as to prevent the direct discharge of wastewater containing heavy hydrocarbons and reduce environmental pollution.

[0029] In some embodiments of this utility model, the third conveying pipeline 500 is further provided with a third switching valve 520 and a fourth switching valve 530; the second regulating valve 510 is disposed on the pipeline between the third switching valve 520 and the fourth switching valve 530. The third switching valve 520 and the fourth switching valve 530 are shut-off valves, that is, installing shut-off valves before and after the second regulating valve 510 can prevent fluid backflow or pressure fluctuations from affecting the second regulating valve 510, ensuring the stable operation and precise control of the second regulating valve 510.

[0030] In some embodiments of this utility model, it further includes: a second parallel pipeline 700; the second parallel pipeline 700 is connected in parallel with the second conveying pipeline 200; the second parallel pipeline 700 is equipped with a second ball valve 710. When the second regulating valve 510 fails to work properly, the flow rate is temporarily controlled by manually operating the second ball valve 710 to ensure stable operation of the system under special operating conditions. If the second regulating valve 510 malfunctions or needs maintenance, the second parallel pipeline 700 can serve as a backup channel to ensure that the system can continue to operate and avoid system shutdown due to problems with the second regulating valve 510.

[0031] In some embodiments of this invention, a fourth conveying pipeline 800 is further included; the fourth conveying pipeline 800 is connected to the gaseous component outlet 320. That is, the gaseous component product gas separated by the separator 300 will be conveyed to the fourth conveying pipeline 800 through the gaseous component outlet 320. The fourth conveying pipeline 800 conveys the product gas to the product gas compressor of the propane dehydrogenation unit for three-stage compression to perform the propane dehydrogenation process.

[0032] In summary, in this embodiment, the first conveying pipe 100 introduces the tail gas of the polypropylene unit into the conveying inlet 310 of the separator 300, so that it can enter the separator 300 together with the product gas from the product gas compressor of the second conveying pipe 200. The separator 300 separates the water and heavy hydrocarbons in the product gas and tail gas, allowing the propylene, propane, and ethylene in the product gas and tail gas to be conveyed from the gaseous component outlet to the product gas compressor of the propane dehydrogenation unit for three-stage compression, thereby realizing the recovery and utilization of the tail gas of the polypropylene unit. Compared with directly discharging the tail gas of the polypropylene unit to the flare system, this embodiment can effectively recover and utilize the propylene and propane in the tail gas of the polypropylene unit, reduce the material consumption of propylene and propane, save production costs, and the demister of the separator 300 can filter out particulate impurities in the tail gas generated by the polypropylene unit, preventing particulate impurities from entering the product gas compressor of the propane dehydrogenation unit, thereby ensuring the safe and stable operation of the product gas compressor of the propane dehydrogenation unit and not affecting the operation of the propane dehydrogenation unit.

[0033] The above are merely preferred embodiments of this utility model. It should be noted that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this utility model, and these improvements and substitutions should also be considered within the protection scope of this utility model.

Claims

1. A polypropylene tail gas recovery system for a propane dehydrogenation unit, characterized in that, include: The system comprises a first conveying pipeline, a second conveying pipeline, a separating tank, and a wastewater treatment device. The first conveying pipeline is used to convey the exhaust gas from the polypropylene unit, and the second conveying pipeline is used to convey the product gas from the product gas compressor. The separating tank has a conveying inlet, and a demister is installed at the conveying inlet. The first and second conveying pipelines are connected to the conveying inlet. A gaseous component outlet is provided at the top of the separating tank, and a liquid component outlet is provided at the bottom of the separating tank. The liquid component outlet is connected to the wastewater treatment device via a third conveying pipeline.

2. The polypropylene tail gas recovery system for a propane dehydrogenation unit according to claim 1, characterized in that, The first conveying pipeline is equipped with a first regulating valve for adjusting the flow rate.

3. The polypropylene tail gas recovery system for a propane dehydrogenation unit according to claim 2, characterized in that, The first conveying pipeline is also provided with a first switching valve and a second switching valve; the first regulating valve is provided on the pipeline between the first switching valve and the second switching valve.

4. The polypropylene tail gas recovery system for a propane dehydrogenation unit according to claim 3, characterized in that, Also includes: A first parallel pipeline; the first parallel pipeline is connected in parallel with the first conveying pipeline; the first parallel pipeline is equipped with a first ball valve.

5. The polypropylene tail gas recovery system for a propane dehydrogenation unit according to claim 1, characterized in that, The third conveying pipeline is equipped with a second regulating valve for adjusting the flow rate.

6. The polypropylene tail gas recovery system for a propane dehydrogenation unit according to claim 5, characterized in that, The third conveying pipeline is also equipped with a third switch valve and a fourth switch valve; the second regulating valve is installed on the pipeline between the third switch valve and the fourth switch valve.

7. The polypropylene tail gas recovery system for a propane dehydrogenation unit according to claim 6, characterized in that, Also includes: The second parallel pipeline is connected in parallel with the second conveying pipeline; the second parallel pipeline is equipped with a second ball valve.

8. The polypropylene tail gas recovery system for a propane dehydrogenation unit according to claim 1, characterized in that, Also includes: A fourth conveying pipeline; the fourth conveying pipeline is connected to the outlet of the gaseous component.

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