An ultra-high purity propylene purification device and process method thereof

Abstract

The application discloses an ultra-high-purity propylene purification device and a process method thereof, and relates to the technical field of low-temperature separation and purification process of chemical industry. The device comprises a raw material dryer, a pre-cooler, a light-removing tower, a heavy-removing tower, a light-removing tower top condenser, a light-removing tower bottom reboiler, a heavy-removing tower top condenser, a heavy-removing tower bottom reboiler, a high-purity propylene liquefier, a high-purity propylene reheater, a propylene refrigeration compressor, a high-purity propylene product pressurizing pump, a propylene residual liquid recovery tank, a high-purity propylene buffer tank, a raw material tank, a raw material pump and a product tank. The application overcomes the problems of low high-purity propylene product yield and excessive energy consumption in the prior low-temperature distillation process by optimizing the process flow of low-temperature distillation, and the device flow is simple, the operation is more convenient, the investment cost and the operation cost are greatly reduced, and the economic performance is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of low-temperature separation and purification technology in the chemical industry, specifically to an ultra-high purity propylene purification device and its process method. Background Technology

[0002] With the rapid development of the domestic semiconductor industry, the demand for electronic-grade propylene, a new material that has emerged in the process of semiconductor technology development, is constantly increasing. Industrial-grade propylene typically has a purity of 99.5%. In order to meet the requirements for use of electronic-grade propylene (purity of 99.99%), impurities that are seriously harmful to semiconductor technology must be removed from industrial-grade propylene.

[0003] Existing technologies have disclosed various methods for preparing high-purity propylene, all employing distillation. However, due to the very low relative volatility of propylene and propane, the theoretical plate number can reach hundreds, resulting in significant equipment investment. Furthermore, adsorption separation for high-purity propylene extraction is unsuitable for large-scale production due to its complex process and numerous influencing factors. Currently, the industry needs a high-purity propylene purification unit that is easy to operate, has a high product yield, low energy consumption, and is suitable for large-scale production to meet the growing demand for high-purity propylene. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing high-purity propylene purification technologies and to provide an ultra-high-purity propylene purification device and process method to meet the ever-evolving requirements of high-purity propylene technology.

[0005] The specific technical solution adopted in this invention is as follows:

[0006] In a first aspect, the present invention provides an ultra-high purity propylene purification device, comprising a light-removal tower and a heavy-removal tower; the top and bottom of the light-removal tower are respectively provided with a light-removal tower top condenser and a light-removal tower bottom reboiler, and the top and bottom of the heavy-removal tower are respectively provided with a heavy-removal tower top condenser and a heavy-removal tower bottom reboiler.

[0007] The precooler, the light propylene top condenser, the light propylene bottom reboiler, the heavy propylene top condenser, the heavy propylene bottom reboiler, the high-purity propylene liquefaction unit, and the high-purity propylene reheater each have a first channel and a second channel that can form a heat exchange contact.

[0008] The raw material tank is connected in sequence to the raw material pump, raw material dryer, first channel of precooler, and light propylene stripping tower via pipelines; the gas outlet at the top of the light propylene stripping tower is connected to the first channel of the top condenser of the light propylene stripping tower, and the liquid outlet at the bottom is connected to the heavy propylene stripping tower via the first channel of the bottom reboiler of the light propylene stripping tower; the gas outlet at the top of the heavy propylene stripping tower is connected in sequence to the first channel of high-purity propylene liquefaction unit, high-purity propylene buffer tank, high-purity propylene product pressurization pump, first channel of high-purity propylene reheater, and product tank via pipelines via the first channel of the bottom reboiler of the heavy propylene stripping tower; the liquid outlet at the bottom of the heavy propylene stripping tower is connected to the propylene residue recovery tank via pipelines via the first channel of the bottom reboiler of the heavy propylene stripping tower.

[0009] Preferably, the system also includes a refrigeration pipeline equipped with a propylene refrigeration compressor; the end of the refrigeration pipeline is divided into a first refrigeration branch and a second refrigeration branch. The first refrigeration branch is connected to the beginning of the refrigeration pipeline after passing through the second channel of the high-purity propylene liquefaction unit and forming a loop. The second refrigeration branch is connected to the beginning of the refrigeration pipeline after passing through the second channel of the heavy removal tower top condenser, the second channel of the light removal tower top condenser, and the second channel of the precooler in sequence and forming a loop.

[0010] The second channel of the bottom reboiler of the light propylene removal tower and the second channel of the bottom reboiler of the heavy propylene removal tower are both used to introduce a heat source; the second channel of the high-purity propylene reheater is used to introduce circulating water.

[0011] Furthermore, a temperature control valve is installed on the pipeline connecting the precooler and the light propylene stripping tower; a pressure control valve is installed on the pipeline connecting the outlet of the top condenser of the light propylene stripping tower; a level control valve is installed on the pipeline connecting the bottom reboiler of the light propylene stripping tower and the heavy propylene stripping tower; a level control valve is installed on the pipeline connecting the bottom reboiler of the heavy propylene stripping tower and the propylene residue recovery tank; a pressure control valve is installed on the pipeline connecting the high-purity propylene liquefaction unit and the high-purity propylene buffer tank; and a level control valve is installed on the pipeline connecting the high-purity propylene buffer tank and the high-purity propylene reheater. A temperature control valve is installed on the first refrigeration branch upstream of the high-purity propylene liquefaction unit and on the second refrigeration branch upstream of the top condenser of the heavy propylene stripping tower.

[0012] Furthermore, the theoretical number of trays for the light-weight removal tower is 35-40, and the theoretical number of trays for the heavy-weight removal tower is 55-60.

[0013] Secondly, the present invention provides a process method for purifying ultra-high purity propylene using the ultra-high purity propylene purification apparatus described in any one of the first aspects, as follows:

[0014] Liquid propylene feedstock is pumped from the feed tank to the feed dryer inlet via a feed pump. After drying, the propylene feedstock enters the precooler inlet, and after cooling, it is depressurized by a throttle valve before entering the light component removal tower inlet. The gas from the light component removal tower distillation enters the first channel of the top condenser of the light component removal tower for heat exchange, and is discharged as a light component gas after being regulated by a pressure control valve. The liquid from the light component removal tower distillation enters the first channel of the bottom reboiler of the light component removal tower for heat exchange, and is discharged as a heavy component gas after being regulated by a liquid level control valve. The liquid from the heavy component removal tower distillation enters the first channel of the bottom reboiler of the heavy component removal tower. The propylene residue obtained after heat exchange in the de-weighting tower and adjustment by the liquid level control valve enters the propylene residue recovery tank for recovery; the gas after distillation in the de-weighting tower enters the first channel of the top condenser of the de-weighting tower for heat exchange, and the obtained high-purity propylene gas enters the first channel of the high-purity propylene liquefaction unit; the liquefied high-purity propylene enters the high-purity propylene product pressurization pump after passing through the high-purity propylene buffer tank, and the pressurized high-purity propylene liquid enters the first channel of the high-purity propylene reheater for heat exchange, and the reheated high-purity propylene liquid at room temperature is collected in the product tank as ultra-high-purity propylene;

[0015] In this process, the propylene refrigerant is compressed by the propylene refrigeration compressor and then enters the first refrigeration branch and the second refrigeration branch as a cold source. The propylene refrigerant enters the second channel of the high-purity propylene liquefaction unit through the first refrigeration branch for heat exchange, and then flows back to the beginning of the refrigeration pipeline to achieve circulation. The propylene refrigerant enters the second channel of the heavy propylene removal tower top condenser, the second channel of the light propylene removal tower top condenser, and the second channel of the precooler through the second refrigeration branch for heat exchange, and then flows back to the beginning of the refrigeration pipeline to achieve circulation.

[0016] Preferably, the temperature of the raw material propylene after being cooled by the precooler is -5℃ to 5℃.

[0017] Preferably, the pressure of the light-weight removal tower is set to 0.3~0.45 MPaG, and the pressure of the heavy-weight removal tower is set to 0.1~0.25 MPaG.

[0018] Preferably, the top temperature of the light-weight removal tower top condenser is controlled between -15℃ and -10℃, and the top temperature of the heavy-weight removal tower top condenser is controlled between -20℃ and -30℃.

[0019] Preferably, the heat source for the reboiler at the bottom of the light component removal tower and the reboiler at the bottom of the heavy component removal tower is provided by circulating water, heat transfer oil, or an electric heater. The bottom temperature of the reboiler at the bottom of the light component removal tower is controlled between 1°C and 10°C, and the bottom temperature of the reboiler at the bottom of the heavy component removal tower is controlled between -20°C and -30°C.

[0020] Preferably, the purity of the high-purity propylene is ≥99.999%.

[0021] This invention employs a two-tower cryogenic distillation method. First, light components are removed from the feedstock in a light component removal tower, and then high-purity propylene liquid product is separated in a heavy component removal tower. This invention, through optimized process organization of cryogenic distillation, offers the following advantages compared to existing technologies:

[0022] The number of trays and the height of the distillation towers for removing light and heavy propylene are significantly reduced, resulting in lower equipment investment costs. The process is simple and easy to operate, the yield of high-purity propylene is greatly improved, the energy consumption is low, and the economic performance is significantly enhanced. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the device of the present invention.

[0024] The attached diagram is labeled as follows: 1. Raw material dryer; 2. Precooler; 3. Light propylene removal tower; 4. Heavy propylene removal tower; 5. Light propylene removal tower top condenser; 6. Light propylene removal tower bottom reboiler; 7. Heavy propylene removal tower top condenser; 8. Heavy propylene removal tower bottom reboiler; 9. High-purity propylene liquefaction unit; 10. High-purity propylene reheater; 11. Propylene refrigeration compressor; 12. High-purity propylene product pressurization pump; 13. Propylene residue recovery tank; 14. High-purity propylene buffer tank; 15. Raw material tank; 16. Raw material pump; 17. Product tank. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Technical features in the various embodiments of the present invention can be combined accordingly without mutual conflict.

[0026] In the description of this invention, it should be understood that when an element is considered to be "connected" to another element, it can be a direct connection to the other element or an indirect connection, i.e., there is an intermediate element. Conversely, when an element is said to be "directly" connected to another element, there is no intermediate element.

[0027] In the description of this invention, it should be understood that the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0028] In the description of this invention, it should be understood that expressions such as "high purity" and "ultra-high purity" are used only for distinguishing purposes and refer to the purified product compared to the raw material. They should not be construed as indicating or implying relative importance or implicitly specifying the purity limit of the indicated technical features.

[0029] like Figure 1 As shown, this invention provides an ultra-high purity propylene purification device, which mainly includes a raw material dryer 1, a precooler 2, a light propylene removal tower 3, a heavy propylene removal tower 4, a light propylene removal tower top condenser 5, a light propylene removal tower bottom reboiler 6, a heavy propylene removal tower top condenser 7, a heavy propylene removal tower bottom reboiler 8, a high-purity propylene liquefaction unit 9, a high-purity propylene reheater 10, a propylene refrigeration compressor 11, a high-purity propylene product pressurization pump 12, a propylene residue recovery tank 13, a high-purity propylene buffer tank 14, a raw material tank 15, a raw material pump 16, a product tank 17, and supporting valves and pipelines.

[0030] Among them, the precooler 2, the light propylene top condenser 5, the light propylene bottom reboiler 6, the heavy propylene top condenser 7, the heavy propylene bottom reboiler 8, the high-purity propylene liquefaction unit 9, and the high-purity propylene reheater 10 each have a first channel and a second channel that can form a heat exchange contact.

[0031] The following is a detailed description of the cooperation and interaction relationships between the components.

[0032] In the apparatus of this invention, the top of the light-weight distillation tower 3 is connected to a top condenser 5, allowing the gas obtained after distillation to enter the top condenser 5 for heat exchange. The bottom of the light-weight distillation tower 3 is connected to a bottom reboiler 6, allowing the liquid obtained after distillation to enter the bottom reboiler 6 for heat exchange. The top of the heavy-weight distillation tower 4 is connected to a top condenser 7, allowing the gas obtained after distillation to enter the top condenser 7 for heat exchange. The bottom of the heavy-weight distillation tower 4 is equipped with a bottom reboiler 8, allowing the liquid obtained after distillation to enter the bottom reboiler 8 for heat exchange.

[0033] In the apparatus of this invention, the raw material tank 15 is connected to the inlet of the raw material pump 16 via a pipeline, the outlet of the raw material pump 16 is connected to the inlet of the raw material dryer 1 via a pipeline, the outlet of the raw material dryer 1 is connected to the inlet of the first channel of the precooler 2 via a pipeline, and the outlet of the first channel of the precooler 2 is connected to the inlet of the light-weight removal tower 3 via a pipeline. The top gas outlet of the light-weight removal tower 3 is connected to the first channel of the top condenser 5 of the light-weight removal tower, and the bottom liquid outlet is connected to the inlet of the first channel of the bottom reboiler 6 of the light-weight removal tower. The outlet of the first channel of the bottom reboiler 6 of the light-weight removal tower is connected to the inlet of the heavy-weight removal tower 4 via a pipeline. The gas outlet at the top of the deweight removal tower 4 is connected to the first channel inlet of the top condenser 7 of the deweight removal tower. The first channel outlet of the top condenser 7 of the deweight removal tower is connected to the first channel inlet of the high-purity propylene liquefaction unit 9 through a pipeline. The first channel outlet of the high-purity propylene liquefaction unit 9 is connected to the inlet of the high-purity propylene buffer tank 14 through a pipeline. The outlet of the high-purity propylene buffer tank 14 is connected to the inlet of the high-purity propylene product pressurization pump 12 through a pipeline. The outlet of the high-purity propylene product pressurization pump 12 is connected to the first channel inlet of the high-purity propylene reheater 10 through a pipeline. The first channel outlet of the high-purity propylene reheater 10 is connected to the inlet of the product tank 17 through a pipeline.

[0034] In a preferred embodiment of the present invention, the device further includes a refrigeration pipeline, on which a propylene refrigeration compressor 11 is installed. The end of the refrigeration pipeline is divided into two parallel pipelines: a first refrigeration branch and a second refrigeration branch. The first refrigeration branch is connected to the beginning of the refrigeration pipeline after passing through the second channel of the high-purity propylene liquefaction unit 9, forming a circulation loop. The second refrigeration branch passes sequentially through the second channel of the heavy propylene removal tower top condenser 7, the second channel of the light propylene removal tower top condenser 5, and the second channel of the precooler 2, before being connected to the beginning of the refrigeration pipeline, forming a circulation loop.

[0035] In addition, the second channel of the reboiler 6 at the bottom of the light propylene removal tower and the second channel of the reboiler 8 at the bottom of the heavy propylene removal tower are both used to introduce a heat source. The second channel of the high-purity propylene reheater 10 is used to introduce circulating water.

[0036] In a preferred embodiment of the present invention, a temperature control valve is provided on the pipeline connecting the precooler 2 and the light propylene stripping tower 3, which can adjust the valve opening based on the temperature feedback of the medium inside the pipeline. A pressure control valve is provided on the pipeline connecting the outlet of the light propylene stripping tower top condenser 5, which can adjust the valve opening based on the pressure feedback of the medium inside the pipeline. A liquid level control valve is provided on the pipeline connecting the light propylene stripping tower bottom reboiler 6 and the heavy propylene stripping tower 4, which can adjust the valve opening based on the liquid level feedback in the light propylene stripping tower bottom reboiler 6. A liquid level control valve is provided on the pipeline connecting the heavy propylene stripping tower bottom reboiler 8 and the propylene residue recovery tank 13, which can adjust the valve opening based on the liquid level feedback in the heavy propylene stripping tower bottom reboiler 8. A pressure control valve is provided on the pipeline connecting the high-purity propylene liquefaction tank 9 and the high-purity propylene buffer tank 14, which can adjust the valve opening based on the pressure feedback of the medium inside the pipeline. A liquid level control valve is provided on the pipeline connecting the high-purity propylene buffer tank 14 and the high-purity propylene reheater 10, which can adjust the valve opening based on the liquid level feedback in the high-purity propylene buffer tank 14. A temperature control valve is installed on the first refrigeration branch upstream of the high-purity propylene liquefaction unit 9, which can adjust the valve opening based on the temperature feedback of the medium inside the pipe. A temperature control valve is also installed on the second refrigeration branch upstream of the top condenser 7 of the de-burden tower, which can adjust the valve opening based on the temperature feedback of the medium inside the pipe.

[0037] In a preferred embodiment of the present invention, the theoretical number of trays in the light-removal tower 3 can be set between 35 and 40, and the theoretical number of trays in the heavy-removal tower 4 can be set between 55 and 60.

[0038] Utilizing any of the above-mentioned ultra-high purity propylene purification devices, the present invention also provides a purification process method for ultra-high purity propylene, the specific purification process method being as follows:

[0039] Liquid propylene is transported from raw material tank 15 to the inlet of raw material dryer 1 via raw material pump 16. After drying, the propylene enters the inlet of precooler 2, and after cooling, it is depressurized by a throttling valve before entering the inlet of light propylene removal tower 3. In actual use, the temperature of the propylene after cooling in precooler 2 is -5℃ to 5℃, preferably around 0℃.

[0040] The gas after distillation in the light component removal tower 3 enters the first channel of the top condenser 5 for heat exchange. After being regulated by the pressure control valve, it is discharged as a light component gas. In actual use, the tower pressure of the light component removal tower 3 is set to 0.3~0.45 MPaG.

[0041] The liquid after distillation in the light-light distillation tower 3 enters the first channel of the reboiler 6 at the bottom of the light-light distillation tower for heat exchange, and then enters the heavy-light distillation tower 4 after being regulated by the liquid level control valve.

[0042] The liquid after distillation in the de-weighting tower 4 enters the first channel of the reboiler 8 at the bottom of the de-weighting tower for heat exchange. The propylene residue obtained after adjustment by the liquid level control valve enters the propylene residue recovery tank 13 for recovery.

[0043] The gas from the distillation process in the heavy propylene removal tower 4 enters the first channel of the top condenser 7 for heat exchange. The resulting high-purity propylene gas (purity ≥ 99.999%) enters the first channel of the high-purity propylene liquefaction tank 9. In actual use, the tower pressure of the heavy propylene removal tower 4 is set to 0.1~0.25 MPaG. After liquefaction, the high-purity propylene passes through the high-purity propylene buffer tank 14 and then enters the high-purity propylene product pressurization pump 12. The pressurized high-purity propylene liquid enters the first channel of the high-purity propylene reheater 10 for heat exchange. The reheated high-purity propylene liquid at room temperature is collected as ultra-high-purity propylene in the product tank 17.

[0044] In actual use, the heat source for the reboiler 6 at the bottom of the light-weight removal tower and the reboiler 8 at the bottom of the heavy-weight removal tower is provided by circulating water, heat transfer oil or electric heater. The bottom temperature of the reboiler 6 at the bottom of the light-weight removal tower is controlled between 1℃ and 10℃, and the bottom temperature of the reboiler 8 at the bottom of the heavy-weight removal tower is controlled between -20℃ and -30℃.

[0045] In the ultra-high purity propylene purification process, propylene refrigerant serves as the cold source for the top condenser 5 of the light component removal tower and the top condenser 7 of the heavy component removal tower, and is supplied by the propylene refrigeration compressor 11. The specific operation is as follows:

[0046] After being compressed by the propylene refrigeration compressor 11, the propylene refrigerant serves as a cold source, entering the first and second refrigeration branches respectively. The propylene refrigerant then enters the second channel of the high-purity propylene liquefaction unit 9 through the first refrigeration branch for heat exchange, and subsequently flows back to the beginning of the refrigeration pipeline, completing the circulation. The propylene refrigerant then sequentially enters the second channel of the heavy propylene removal tower top condenser 7, the second channel of the light propylene removal tower top condenser 5, and the second channel of the precooler 2 through the second refrigeration branch for heat exchange, and subsequently flows back to the beginning of the refrigeration pipeline, completing the circulation.

[0047] In practical use, the top temperature of the light-weight removal tower top condenser 5 can be controlled between -15℃ and -10℃, and the top temperature of the heavy-weight removal tower top condenser 7 can be controlled between -20℃ and -30℃.

[0048] This invention overcomes the problems of low yield of high-purity propylene and excessive energy consumption in existing low-temperature distillation processes by optimizing the process flow of low-temperature distillation. Furthermore, the equipment process is simple, easier to operate, and investment and operating costs are significantly reduced, resulting in a substantial improvement in economic performance.

[0049] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, all technical solutions obtained through equivalent substitution or transformation fall within the protection scope of the present invention.

Claims

1. A device for purifying ultra-high purity propylene, characterized in that, It includes a light-removal tower (3) and a heavy-removal tower (4); the top and bottom of the light-removal tower (3) are respectively equipped with a light-removal tower top condenser (5) and a light-removal tower bottom reboiler (6), and the top and bottom of the heavy-removal tower (4) are respectively equipped with a heavy-removal tower top condenser (7) and a heavy-removal tower bottom reboiler (8). The precooler (2), the light-removal tower top condenser (5), the light-removal tower bottom reboiler (6), the heavy-removal tower top condenser (7), the heavy-removal tower bottom reboiler (8), the high-purity propylene liquefaction unit (9), and the high-purity propylene reheater (10) each have a first channel and a second channel that can form heat exchange contact. The raw material tank (15) is connected in sequence to the raw material pump (16), the raw material dryer (1), the first channel of the precooler (2), and the light-light removal tower (3) via pipelines; the gas outlet at the top of the light-light removal tower (3) is connected to the first channel of the light-light removal tower top condenser (5), and the liquid outlet at the bottom is connected to the heavy removal tower (4) via the first channel of the light-light removal tower bottom reboiler (6); the gas outlet at the top of the heavy removal tower (4) is connected in sequence to the first channel of the high-purity propylene liquefaction unit (9), the high-purity propylene buffer tank (14), the high-purity propylene product pressurization pump (12), the first channel of the high-purity propylene reheater (10), and the product tank (17) via pipelines via the first channel of the heavy removal tower bottom reboiler (8); the liquid outlet at the bottom of the heavy removal tower (4) is connected to the propylene residue recovery tank (13) via pipelines via the first channel of the heavy removal tower bottom reboiler (8). It also includes a refrigeration pipeline equipped with a propylene refrigeration compressor (11); the end of the refrigeration pipeline is divided into a first refrigeration branch and a second refrigeration branch. The first refrigeration branch is connected to the beginning of the refrigeration pipeline after passing through the second channel of the high-purity propylene liquefaction unit (9) and forming a loop. The second refrigeration branch is connected to the beginning of the refrigeration pipeline after passing through the second channel of the heavy removal tower top condenser (7), the second channel of the light removal tower top condenser (5), and the second channel of the precooler (2) in sequence and forming a loop. The second channel of the bottom reboiler (6) of the light propylene removal tower and the second channel of the bottom reboiler (8) of the heavy propylene removal tower are both used to introduce a heat source; the second channel of the high-purity propylene reheater (10) is used to introduce circulating water. The theoretical number of trays for the light removal tower (3) is 35-40, and the theoretical number of trays for the heavy removal tower (4) is 55-60.

2. The ultra-high purity propylene purification device according to claim 1, characterized in that, Temperature control valves are provided on the pipelines connecting the precooler (2) and the light-weight removal tower (3), pressure control valves are provided on the pipelines connecting the outlet of the light-weight removal tower top condenser (5), level control valves are provided on the pipelines connecting the light-weight removal tower bottom reboiler (6) and the heavy-weight removal tower (4), level control valves are provided on the pipelines connecting the heavy-weight removal tower bottom reboiler (8) and the propylene residue recovery tank (13), pressure control valves are provided on the pipelines connecting the high-purity propylene liquefaction unit (9) and the high-purity propylene buffer tank (14), and level control valves are provided on the pipelines connecting the high-purity propylene buffer tank (14) and the high-purity propylene reheater (10); temperature control valves are provided on the first refrigeration branch upstream of the high-purity propylene liquefaction unit (9) and on the second refrigeration branch upstream of the heavy-weight removal tower top condenser (7).

3. A process method using the ultra-high purity propylene purification apparatus according to claim 1 or 2, characterized in that, Specifically as follows: Liquid propylene is transported from the raw material tank (15) to the inlet of the raw material dryer (1) via the raw material pump (16). After drying, the raw material propylene enters the inlet of the precooler (2), and after cooling, it is depressurized by the throttle valve and then connected to the inlet of the light component removal tower (3). The gas after distillation in the light component removal tower (3) enters the first channel of the top condenser (5) of the light component removal tower for heat exchange. After being regulated by the pressure control valve, it is discharged as a light component gas. The liquid after distillation in the light component removal tower (3) enters the first channel of the bottom reboiler (6) of the light component removal tower for heat exchange. After being regulated by the liquid level control valve, it enters the heavy component removal tower (4). The liquid after distillation in the heavy component removal tower (4) enters the bottom reboiler (8) of the heavy component removal tower. The first channel of the propylene residue is heat exchanged, and the propylene residue obtained after adjustment by the liquid level control valve enters the propylene residue recovery tank (13) for recovery; the gas after distillation in the de-weighting tower (4) enters the first channel of the top condenser (7) of the de-weighting tower for heat exchange, and the obtained high-purity propylene gas enters the first channel of the high-purity propylene liquefaction tank (9); the high-purity propylene after liquefaction enters the high-purity propylene product pressurization pump (12) after passing through the high-purity propylene buffer tank (14), and the high-purity propylene liquid after pressurization enters the first channel of the high-purity propylene reheater (10) for heat exchange, and the high-purity propylene liquid reheated to room temperature is collected in the product tank (17) as ultra-high-purity propylene; In this process, the propylene refrigerant is compressed by the propylene refrigeration compressor (11) and enters the first refrigeration branch and the second refrigeration branch as a cold source. The propylene refrigerant enters the second channel of the high-purity propylene liquefaction unit (9) through the first refrigeration branch for heat exchange, and then flows back to the beginning of the refrigeration pipeline to achieve circulation. The propylene refrigerant enters the second channel of the heavy removal tower top condenser (7), the second channel of the light removal tower top condenser (5), and the second channel of the precooler (2) through the second refrigeration branch for heat exchange, and then flows back to the beginning of the refrigeration pipeline to achieve circulation.

4. The process method according to claim 3, characterized in that, The temperature of the raw material propylene after being cooled by the precooler (2) is -5℃ to 5℃.

5. The process method according to claim 3, characterized in that, The pressure of the light-removal tower (3) is set to 0.3~0.45 MPaG, and the pressure of the heavy-removal tower (4) is set to 0.1~0.25 MPaG.

6. The process method according to claim 3, characterized in that, The top temperature of the light-weight removal tower top condenser (5) is controlled between -15℃ and -10℃, and the top temperature of the heavy-weight removal tower top condenser (7) is controlled between -20℃ and -30℃.

7. The process method according to claim 3, characterized in that, The heat source for the reboiler (6) at the bottom of the light-removal tower and the reboiler (8) at the bottom of the heavy-removal tower is provided by circulating water, heat transfer oil or electric heater. The bottom temperature of the reboiler (6) at the bottom of the light-removal tower is controlled between 1℃ and 10℃, and the bottom temperature of the reboiler (8) at the bottom of the heavy-removal tower is controlled between -20℃ and -30℃.

8. The process method according to claim 3, characterized in that, The purity of the high-purity propylene is ≥99.999%.

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