Ultrahigh-purity propylene purification device and process method thereof

Abstract

The invention discloses an ultra-pure propylene purification device and a process method thereof, and relates to the technical field of chemical low-temperature separation and purification processes. The device comprises a raw material dryer, a precooler, a light component removal tower, a heavy component removal tower, a light component removal tower top condenser, a light component removal tower bottom reboiler, a heavy component removal tower top condenser, a heavy component removal tower bottom reboiler, a high-purity propylene liquefier, a high-purity propylene reheater, a propylene refrigeration compressor, a high-purity propylene product pressure 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. According to the method, the problems of low yield of a high-purity propylene product, overlarge energy consumption and the like in the existing low-temperature rectification process are solved by optimizing the process flow structure of low-temperature rectification, the device flow is simple, the operation is more convenient, the investment cost and the operation cost are also greatly reduced, and the economic performance is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical low-temperature separation and purification technology, and in particular to an ultra-high-purity propylene purification device and a process method thereof. Background Art

[0002] With the rapid development of the domestic semiconductor industry, demand for electronic-grade propylene, a new material emerging in the development of semiconductor technology, is growing. Industrial-grade propylene typically has a purity of 99.5%. To meet the requirements for electronic-grade propylene (99.99%), impurities that are severely harmful to semiconductor technology must be removed from industrial-grade propylene.

[0003] Several methods for producing high-purity propylene have been disclosed in the prior art. All of these methods utilize distillation. However, due to the very low relative volatility of propylene and propane, the number of theoretical plates can reach hundreds, requiring significant equipment investment. Furthermore, methods that utilize adsorption separation to extract high-purity propylene are complex and subject to numerous influencing factors, making them unsuitable for large-scale production. Currently, the industry needs a high-purity propylene purification device that is easy to operate, offers high product yields, and reduces energy consumption, suitable for large-scale production, to meet the growing demand for high-purity propylene. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art high-purity propylene purification technology and provide an ultra-high-purity propylene purification device and process method to meet the ever-evolving high-purity propylene technology requirements.

[0005] The specific technical solutions adopted in the present invention are as follows:

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

[0007] The precooler, the light removal tower top condenser, the light removal tower bottom reboiler, the heavy removal tower top condenser, the heavy removal tower bottom reboiler, the high-purity propylene liquefier and the high-purity propylene reheater are each provided with a first channel and a second channel capable of forming heat exchange contact;

[0008] The raw material tank is connected to the raw material pump, the raw material dryer, the first channel of the precooler, and the lightness removal tower in sequence through pipelines; the gas outlet at the top of the lightness removal tower is connected to the first channel of the condenser at the top of the lightness removal tower, and the liquid outlet at the bottom is connected to the heavyness removal tower after passing through the first channel of the reboiler at the bottom of the lightness removal tower; the gas outlet at the top of the heavyness removal tower is connected to the first channel of the high-purity propylene liquefier, the high-purity propylene buffer tank, the high-purity propylene product pressure pump, the first channel of the high-purity propylene reheater, and the product tank in sequence through pipelines after passing through the first channel of the condenser at the top of the heavyness removal tower; the liquid outlet at the bottom of the heavyness removal tower is connected to the propylene residual liquid recovery tank through a pipeline after passing through the first channel of the reboiler at the bottom of the heavyness removal tower.

[0009] Preferably, the system further comprises a refrigeration pipeline provided 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 passes through the second channel of the high-purity propylene liquefier and is connected to the head end of the refrigeration pipeline to form a loop, and the second refrigeration branch passes through the second channel of the de-weight removal tower top condenser, the second channel of the light removal tower top condenser, and the second channel of the precooler in sequence and is connected to the head end of the refrigeration pipeline to form a loop;

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

[0011] Furthermore, a temperature control valve is provided on the pipeline connecting the precooler and the lightness removal tower, a pressure control valve is provided on the pipeline connecting the outlet of the condenser at the top of the lightness removal tower, a liquid level control valve is provided on the pipeline connecting the reboiler at the bottom of the lightness removal tower and the heavy removal tower, a liquid level control valve is provided on the pipeline connecting the reboiler at the bottom of the heavy removal tower and the propylene residual liquid recovery tank, a pressure control valve is provided on the pipeline connecting the high-purity propylene liquefier and the high-purity propylene buffer tank, and a liquid level control valve is provided on the pipeline connecting the high-purity propylene buffer tank and the high-purity propylene reheater; a temperature control valve is provided on the first refrigeration branch upstream of the high-purity propylene liquefier, and a temperature control valve is provided on the second refrigeration branch upstream of the condenser at the top of the heavy removal tower.

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

[0013] In a second aspect, the present invention provides a process method using the ultra-high purity propylene purification device according to any one of the first aspects, which is as follows:

[0014] The liquid raw material propylene is transported from the raw material tank to the raw material dryer inlet through the raw material pump. After drying, the raw material propylene enters the precooler inlet, is cooled, and is depressurized by the throttle valve before being connected to the de-lightening tower inlet. The gas after distillation in the de-lightening tower enters the first channel of the de-lightening tower top condenser for heat exchange, and is discharged as light component gas after being adjusted by the pressure control valve. The liquid after distillation in the de-lightening tower enters the first channel of the de-lightening tower bottom reboiler for heat exchange, and enters the de-heavy tower after being adjusted by the liquid level control valve. The liquid after distillation in the de-heavy tower enters the first channel of the de-lightening tower bottom reboiler for heat exchange, and enters the de-heavy tower after being adjusted by the liquid level control valve. The propylene residue obtained after adjustment by the liquid level control valve enters the propylene residue recovery tank for recovery; the gas after distillation in the deweighting tower enters the first channel of the deweighting tower top condenser for heat exchange, and the obtained high-purity propylene gas enters the first channel of the high-purity propylene liquefier; the liquefied high-purity propylene enters the high-purity propylene product pressure 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 high-purity propylene liquid reheated to room temperature is collected in the product tank as ultra-high-purity propylene;

[0015] In this process, after being compressed by the propylene refrigeration compressor, the propylene refrigerant 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 liquefier through the first refrigeration branch for heat exchange, and then flows back to the head end of the refrigeration pipeline to complete the circulation; the propylene refrigerant enters the second channel of the de-weighting tower top condenser, the second channel of the de-lighting tower top condenser, and the second channel of the precooler in turn through the second refrigeration branch for heat exchange, and then flows back to the head end of the refrigeration pipeline to complete the circulation.

[0016] Preferably, the temperature of the raw material propylene after being cooled in a precooler is -5°C to 5°C.

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

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

[0019] Preferably, the heat sources of the de-light tower bottom reboiler and the de-heavy tower bottom reboiler are provided by circulating water, heat transfer oil or electric heater, the bottom temperature of the de-light tower bottom reboiler is controlled between 1°C and 10°C, and the bottom temperature of the de-heavy tower bottom reboiler is controlled between -20°C and -30°C.

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

[0021] The present invention uses a two-tower cryogenic distillation process to first remove light components from the feedstock in a light fraction removal column, and then separate a high-purity propylene liquid product in a heavy fraction removal column. By optimizing the cryogenic distillation process, the present invention has the following advantages over existing technologies:

[0022] The number of distillation trays and the height of the light removal tower and heavy removal tower are greatly reduced, and the equipment investment cost is reduced; the process is simple and easy to operate, the yield of high-purity propylene products is greatly improved, the operating energy consumption is low, and the economic performance is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the device of the present invention.

[0024] The accompanying drawings are marked as follows: raw material dryer 1, precooler 2, lightness removal tower 3, heavyness removal tower 4, lightness removal tower top condenser 5, lightness removal tower bottom reboiler 6, heavyness removal tower top condenser 7, heavyness removal tower bottom reboiler 8, high-purity propylene liquefier 9, high-purity propylene reheater 10, propylene refrigeration compressor 11, high-purity propylene product booster pump 12, propylene residual liquid recovery tank 13, high-purity propylene buffer tank 14, raw material tank 15, raw material pump 16, product tank 17. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in the various embodiments of the present invention can be combined accordingly without conflicting with each other.

[0026] In the description of the present invention, it should be understood that when an element is considered to be "connected" to another element, it can be directly connected to the other element or indirectly connected, that is, there are intermediate elements. On the contrary, when an element is said to be "directly" connected to another element, there are no intermediate elements.

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

[0028] In the description of the present invention, it should be understood that expressions such as "high purity" and "ultra-high purity" are only used for descriptive purposes to distinguish products after purification compared to the raw materials, and should not be understood as indicating or implying relative importance or implicitly indicating the purity limit of the indicated technical characteristics.

[0029] like Figure 1 As shown, an ultra-high purity propylene purification device provided by the present invention mainly includes a raw material dryer 1, a precooler 2, a lightness removal tower 3, a heavyness removal tower 4, a lightness removal tower top condenser 5, a lightness removal tower bottom reboiler 6, a heavyness removal tower top condenser 7, a heavyness removal tower bottom reboiler 8, a high-purity propylene liquefier 9, a high-purity propylene reheater 10, a propylene refrigeration compressor 11, a high-purity propylene product pressure pump 12, a propylene residual liquid 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, pipelines and other equipment.

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

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

[0032] In the device of the present invention, the top of the lightness removal tower 3 is connected to the lightness removal tower top condenser 5, and the gas obtained after distillation can enter the lightness removal tower top condenser 5 to achieve heat exchange. The bottom of the lightness removal tower 3 is connected to the lightness removal tower bottom reboiler 6, and the liquid obtained after distillation can enter the lightness removal tower bottom reboiler 6 to achieve heat exchange. The top of the weight removal tower 4 is connected to the weight removal tower top condenser 7, and the gas obtained after distillation can enter the weight removal tower top condenser 7 to achieve heat exchange. The bottom of the weight removal tower 4 is provided with a weight removal tower bottom reboiler 8, and the liquid obtained after distillation can enter the weight removal tower bottom reboiler 8 to achieve heat exchange.

[0033] In the device of the present 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-removing tower 3 via a pipeline. The gas outlet at the top of the light-removing tower 3 is connected to the first channel of the light-removing tower top condenser 5, and the liquid outlet at the bottom is connected to the inlet of the first channel of the light-removing tower bottom reboiler 6. The outlet of the first channel of the light-removing tower bottom reboiler 6 is connected to the inlet of the heavy-removing tower 4 via a pipeline. The gas outlet at the top of the deweighting tower 4 is connected to the first channel inlet of the deweighting tower top condenser 7, the first channel outlet of the deweighting tower top condenser 7 is connected to the first channel inlet of the high-purity propylene liquefier 9 through a pipeline, the first channel outlet of the high-purity propylene liquefier 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 pressure pump 12 through a pipeline, the outlet of the high-purity propylene product pressure pump 12 is connected to the first channel inlet of the high-purity propylene reheater 10 through a pipeline, and the first channel outlet of the high-purity propylene reheater 10 is connected to the inlet of the propylene residual liquid recovery tank 13 through a pipeline.

[0034] As a preferred embodiment of the present invention, the apparatus further includes a refrigeration pipeline equipped with a propylene refrigeration compressor 11. 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 passes through the second channel of the high-purity propylene liquefier 9 and then connects to the head end of the refrigeration pipeline, forming a circulation loop. The second refrigeration branch passes through the second channel of the de-heavy tower top condenser 7, the second channel of the de-light tower top condenser 5, and the second channel of the precooler 2, before connecting to the head end of the refrigeration pipeline, forming a circulation loop.

[0035] In addition, the second channel of the light removal tower bottom reboiler 6 and the second channel of the heavy removal tower bottom reboiler 8 are both used to introduce heat sources. 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 lightness removal column 3, capable of adjusting the valve opening based on the temperature feedback of the medium in the pipeline. A pressure control valve is provided on the pipeline connecting the outlet of the lightness removal column top condenser 5, capable of adjusting the valve opening based on the pressure feedback of the medium in the pipeline. A liquid level control valve is provided on the pipeline connecting the lightness removal column bottom reboiler 6 and the heavy removal column 4, capable of adjusting the valve opening based on the liquid level in the lightness removal column bottom reboiler 6. A liquid level control valve is provided on the pipeline connecting the heavy removal column bottom reboiler 8 and the propylene residual liquid recovery tank 13, capable of adjusting the valve opening based on the liquid level in the heavy removal column bottom reboiler 8. A pressure control valve is provided on the pipeline connecting the high-purity propylene liquefier 9 and the high-purity propylene buffer tank 14, capable of adjusting the valve opening based on the pressure feedback of the medium in 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, capable of adjusting the valve opening based on the liquid level 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 liquefier 9, which can adjust the valve opening based on the temperature feedback of the medium in the pipe. A temperature control valve is installed on the second refrigeration branch upstream of the deweighting tower top condenser 7, which can adjust the valve opening based on the temperature feedback of the medium in the pipe.

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

[0038] The present invention further provides a method for purifying ultra-high-purity propylene using any of the above-mentioned ultra-high-purity propylene purification devices. The method is specifically as follows:

[0039] Liquid propylene feedstock is delivered from feedstock tank 15 via feedstock pump 16 to the inlet of feedstock dryer 1. After drying, the propylene feedstock enters the inlet of precooler 2. After cooling, the propylene feedstock is depressurized by a throttle valve and then fed to the inlet of lightness removal tower 6. In actual use, the temperature of the propylene feedstock after cooling in precooler 2 is between -5°C and 5°C, preferably around 0°C.

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

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

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

[0043] The gas distilled from de-weighting tower 4 enters the first channel of de-weighting tower overhead condenser 7 for heat exchange. The resulting high-purity propylene (purity ≥99.999%) enters the first channel of high-purity propylene liquefier 9. In actual operation, the pressure of de-weighting tower 4 is set at 0.1-0.25 MPaG. The liquefied high-purity propylene passes through a high-purity propylene buffer tank 14 and enters a high-purity propylene product pressure pump 12. The pressurized high-purity propylene liquid enters the first channel of a high-purity propylene reheater 10 for heat exchange. The reheated high-purity propylene liquid, now at room temperature, is collected in product tank 17 as ultra-high-purity propylene.

[0044] In actual use, the heat sources of the de-light tower bottom reboiler 6 and the de-heavy tower bottom reboiler 8 are provided by circulating water or heat transfer oil or electric heater. The bottom temperature of the de-light tower bottom reboiler 6 is controlled between 1°C and 10°C, and the bottom temperature of the de-heavy tower bottom reboiler 8 is controlled between -20°C and -30°C.

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

[0046] After propylene refrigerant is compressed by propylene refrigeration compressor 11, it enters the first refrigeration branch and the second refrigeration branch respectively as a cold source. Propylene refrigerant enters the second channel of high-purity propylene liquefier 9 by the first refrigeration branch and exchanges heat, and then flows back to the head end of refrigeration line, realizing circulation. Propylene refrigerant enters the second channel of de-weighting tower top condenser 7, the second channel of lightness removal tower top condenser 5, the second channel of precooler 2 successively by the second refrigeration branch and exchanges heat respectively, and then flows back to the head end of refrigeration line, realizing circulation.

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

[0048] The present invention overcomes the problems of low yield of high-purity propylene products and excessive energy consumption in existing cryogenic distillation processes by optimizing the process organization of cryogenic distillation. In addition, the device process is simple, the operation is more convenient, the investment cost and the operating cost are greatly reduced, and the economic performance is greatly improved.

[0049] The above embodiment is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Persons skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent substitution or equivalent transformation falls within the scope of protection of the present invention.

Claims

1. An ultra-high purity propylene purification device, characterized in that: The invention comprises a light-removal tower (3) and a heavy-removal tower (4); a light-removal tower top condenser (5) and a light-removal tower bottom reboiler (6) are provided at the top and bottom of the light-removal tower (3), respectively; a heavy-removal tower top condenser (7) and a heavy-removal tower bottom reboiler (8) are provided at the top and bottom of the heavy-removal tower (4); 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 liquefier (9) and the high-purity propylene reheater (10) each have a first channel and a second channel capable of forming heat exchange contact therein; The raw material tank (15) is connected to the raw material pump (16), the raw material dryer (1), the first channel of the precooler (2), and the lightness removal tower (3) in sequence through pipelines; the gas outlet at the top of the lightness removal tower (3) is connected to the first channel of the lightness removal tower top condenser (5), and the liquid outlet at the bottom is connected to the de-weight removal tower (4) after passing through the first channel of the lightness removal tower bottom reboiler (6); the gas outlet at the top of the de-weight removal tower (4) is connected to the first channel of the high-purity propylene liquefier (9), the high-purity propylene buffer tank (14), the high-purity propylene product pressure pump (12), the first channel of the high-purity propylene reheater (10), and the product tank (17) in sequence through pipelines after passing through the first channel of the de-weight removal tower bottom reboiler (8). The liquid outlet at the bottom of the de-weight removal tower (4) is connected to the propylene residual liquid recovery tank (13) through a pipeline after passing through the first channel of the de-weight removal tower bottom reboiler (8).

2. The ultra-high purity propylene purification device according to claim 1, characterized in that: The refrigeration system further comprises a refrigeration pipeline provided 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 head end of the refrigeration pipeline after passing through the second channel of the high-purity propylene liquefier (9) to form a loop, and the second refrigeration branch is connected to the head end of the refrigeration pipeline after passing through the second channel of the de-weighting tower top condenser (7), the second channel of the de-lighting tower top condenser (5), and the second channel of the precooler (2) to form a loop; The second channel of the light removal tower bottom reboiler (6) and the second channel of the heavy removal tower bottom reboiler (8) are both used for introducing a heat source; the second channel of the high-purity propylene reheater (10) is used for introducing circulating water.

3. The ultra-high purity propylene purification device according to claim 2, characterized in that: A temperature control valve is provided on the pipeline connecting the precooler (2) and the lightness removal tower (3); a pressure control valve is provided on the pipeline connecting the outlet of the lightness removal tower top condenser (5); a liquid level control valve is provided on the pipeline connecting the lightness removal tower bottom reboiler (6) and the heavy removal tower (4); a liquid level control valve is provided on the pipeline connecting the heavy removal tower bottom reboiler (8) and the propylene residual liquid recovery tank (13); a pressure control valve is provided on the pipeline connecting the high-purity propylene liquefier (9) and the high-purity propylene buffer tank (14); and 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); a temperature control valve is provided on the first refrigeration branch upstream of the high-purity propylene liquefier (9); and a temperature control valve is provided on the second refrigeration branch upstream of the heavy removal tower top condenser (7).

4. The ultra-high purity propylene purification device according to claim 2, characterized in that: The theoretical number of trays of the light removal tower (3) is 35 to 40, and the theoretical number of trays of the heavy removal tower (4) is 55 to 60.

5. A process using the ultra-high purity propylene purification device according to any one of claims 2 to 4, characterized in that: The details are as follows: The liquid raw material propylene is transported from the raw material tank (15) to the inlet of the raw material dryer (1) through the raw material pump (16). After drying, the raw material propylene enters the inlet of the precooler (2), is cooled, and is depressurized by the throttle valve before being connected to the inlet of the de-lightening tower (6); the gas after distillation in the de-lightening tower (3) enters the first channel of the de-lightening tower top condenser (5) for heat exchange, and is discharged as light component gas after being regulated by the pressure control valve; the liquid after distillation in the de-lightening tower (3) enters the first channel of the de-lightening tower bottom reboiler (6) for heat exchange, and enters the de-weighting tower (4) after being regulated by the liquid level control valve; the liquid after distillation in the de-weighting tower (4) enters the de-weighting tower bottom reboiler (8 ) for heat exchange, 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 deweighting tower (4) enters the first channel of the deweighting tower top condenser (7) for heat exchange, and the high-purity propylene gas obtained enters the first channel of the high-purity propylene liquefier (9); the liquefied high-purity propylene enters the high-purity propylene product pressure pump (12) after passing through the high-purity propylene buffer tank (14), and the pressurized high-purity propylene liquid 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, after being compressed by a propylene refrigeration compressor (11), the propylene refrigerant 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 liquefier (9) through the first refrigeration branch for heat exchange, and then flows back to the head end of the refrigeration pipeline to achieve circulation; the propylene refrigerant enters the second channel of the de-weighting tower top condenser (7), the second channel of the de-lighting tower top condenser (5), and the second channel of the precooler (2) in sequence through the second refrigeration branch for heat exchange, and then flows back to the head end of the refrigeration pipeline to achieve circulation.

6. The process according to claim 5, characterized in that: The temperature of the raw material propylene after being cooled by the precooler (2) is -5°C to 5°C.

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

8. The process according to claim 5, characterized in that: The top temperature of the light removal tower top condenser (5) is controlled between -15°C and -10°C, and the top temperature of the heavy removal tower top condenser (7) is controlled between -20°C and -30°C.

9. The process according to claim 5, characterized in that: The heat sources of the de-light tower bottom reboiler (6) and the de-heavy tower bottom reboiler (8) are provided by circulating water, heat-conducting oil or an electric heater. The bottom temperature of the de-light tower bottom reboiler (6) is controlled between 1°C and 10°C, and the bottom temperature of the de-heavy tower bottom reboiler (8) is controlled between -20°C and -30°C.

10. The process according to claim 5, characterized in that: The purity of the high-purity propylene is ≥99.999%.

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