Device and method for efficiently purifying octafluoropropane

Abstract

The invention provides a device for efficiently purifying octafluoropropane, the device is divided into three stages of towers, namely a first-stage de-heavy tower, a second-stage de-light tower and a third-stage dehydrating tower, the first-stage de-heavy tower and the second-stage de-light tower are respectively composed of an upper tower and a lower tower and are two-stage rectifying towers, the third-stage dehydrating tower is a one-stage conventional rectifying tower, and the upper tower and the lower tower are two-stage rectifying towers. An upper tower liquid phase of the two-section rectifying tower enters the lower tower through forced conveying, a lower tower gas phase enters the upper tower through spontaneous conveying, and the separation effect is obviously higher than that of a conventional rectifying tower; the invention also provides a method for efficiently purifying octafluoropropane, which comprises the following steps of: heating and vaporizing an octafluoropropane crude product in the raw material tank to enter the first-stage heavy component removal tower to remove heavy component impurities, extracting the primarily purified octafluoropropane from the top of the first-stage heavy component removal tower, and entering the second-stage light component removal tower to remove light component impurities; the octafluoropropane after two-step purification enters a three-stage dehydration tower for further dehydration, so that electronic-grade octafluoropropane gas with the purity being greater than 99.999% can be obtained. The method is simple in process and mild in operation condition.

Description

Technical Field

[0001] The invention relates to a high-efficiency purification device and method of octafluoropropane by multi-tower series distillation, belonging to the field of chemical separation. Background Art

[0002] High-purity octafluoropropane (purity greater than 99.999%) is a perfluorinated electronic specialty gas with good stability, excellent insulation, low atmospheric life and efficient etching and cleaning performance. It has been widely used in industries such as medicine, refrigeration, semiconductors and integrated circuits.

[0003] At present, high-purity octafluoropropane is obtained by combining two or more methods such as distillation, adsorption, impurity conversion and membrane separation for purification. Chinese patent CN202410202329.X provides a method for purifying octafluoropropane by extractive distillation technology, comprising the following steps: (1) extractive distillation; the extractant and the crude octafluoropropane enter the extractive distillation tower together, wherein the mass ratio of the crude octafluoropropane to the extractant is 1:3-7, and the reflux ratio is 2:1-6; (2) adsorption; the crude octafluoropropane after extractive distillation is passed into the adsorption tower filled with adsorbent, the adsorption temperature is 10-30°C, the pressure is 0.1-0.6MPa, and the flow rate is 15-25kg / h to obtain purified octafluoropropane; the adsorbent described in step (2) is a copper salt-doped modified crystalline silicon-aluminum zeolite molecular sieve adsorbent. The process is relatively complicated, and the extraction agent needs to be added, and the production efficiency is low.

[0004] Chinese patent CN202311416436.4 discloses a method for purifying high-purity octafluoropropane, which specifically includes the following steps: first, filtering the unpurified octafluoropropane raw material stored in the storage tank for particles; second, passing the filtered octafluoropropane into a heavy-removal distillation tower, performing a primary distillation on the octafluoropropane to remove the heavy impurities in the octafluoropropane; then, passing the octafluoropropane from which the heavy impurities have been removed into a light-removal distillation tower, performing a secondary distillation on the octafluoropropane to remove the light impurities in the octafluoropropane; finally, performing an adsorption operation on the octafluoropropane from which the light impurities have been removed, and high-purity octafluoropropane can be obtained. When using a purification process containing an adsorption method, the adsorbent needs to be activated and regenerated, and the adsorption capacity of the adsorbent will also change with the continuous purification of the crude product, and the stability of the entire purification process is poor. When using a purification process containing an impurity conversion method or a membrane separation method, the operating cost will be relatively high.

[0005] Therefore, it is particularly necessary to seek a method for purifying octafluoropropane with simple process and good economic efficiency. Summary of the invention

[0006] The purpose of the present invention is to provide an efficient purification device and method for octafluoropropane, which has simple process, good stability, effectively removes impurities in octafluoropropane, and finally achieves a purity of octafluoropropane greater than 99.999%.

[0007] The present invention provides the following technical solutions:

[0008] An efficient device for purifying octafluoropropane comprises a raw material tank, an upper tower of a primary deheaving tower, a lower tower of a primary deheaving tower, a deheaving reflux pump, an upper tower of a secondary deheaving tower, a lower tower of a secondary deheaving tower, a deheaving reflux pump and a tertiary dehydration tower;

[0009] The raw material tank is provided with a raw material tank discharge port, the lower tower of the first-level de-weighting tower is provided with a raw material feed port of the first-level de-weighting tower, a reflux feed port of the lower tower of the first-level de-weighting tower and a top discharge port of the lower tower of the first-level de-weighting tower, the upper tower of the first-level de-weighting tower is provided with a feed port of the upper tower of the first-level de-weighting tower, a top discharge port of the upper tower of the first-level de-weighting tower and a discharge port of the upper kettle of the first-level de-weighting tower, the upper tower of the second-level de-lighting tower is provided with a raw material feed port of the second-level de-lighting tower, a feed port of the upper tower of the second-level de-lighting tower and a discharge port of the upper kettle of the second-level de-lighting tower, the lower tower of the second-level de-lighting tower is provided with a discharge port of the lower kettle of the second-level de-lighting tower, a reflux feed port of the lower tower of the second-level de-lighting tower and a top discharge port of the lower tower of the second-level de-lighting tower, and the third-level de-watering tower is provided with a raw material feed port of the third-level de-watering tower and a discharge port of the third-level de-watering tower;

[0010] The discharge port of the raw material tank is connected to the raw material feed port of the first-stage de-weighting tower through a pipeline, the discharge port of the lower tower top of the first-stage de-weighting tower is connected to the feed port of the upper tower of the first-stage de-weighting tower through a pipeline, the discharge port of the upper tower kettle of the first-stage de-weighting tower is connected to the reflux feed port of the lower tower of the first-stage de-weighting tower through a pipeline, the upper tower top discharge port of the first-stage de-weighting tower is connected to the raw material feed port of the second-stage de-lighting tower through a pipeline, the upper tower kettle discharge port of the second-stage de-lighting tower is connected to the reflux feed port of the lower tower of the second-stage de-lighting tower through a pipeline, the lower tower top discharge port of the second-stage de-lighting tower is connected to the feed port of the upper tower of the second-stage de-lighting tower through a pipeline, and the lower tower kettle discharge port of the second-stage de-lighting tower is connected to the raw material feed port of the tertiary dehydration tower through a pipeline.

[0011] Preferably, a de-heavy-ness reflux pump is provided on the pipeline between the discharge port of the upper kettle of the first de-heavy-ness tower and the reflux feed port of the lower kettle of the first de-heavy-ness tower, and a de-light-ness reflux pump is provided on the pipeline between the discharge port of the upper kettle of the second de-light-ness tower and the reflux feed port of the lower kettle of the second de-light-ness tower.

[0012] Preferably, a condenser is arranged at the top of the upper tower of the first-stage deheavy tower to provide reflux liquid of the upper tower, and a heater is arranged at the kettle of the lower tower of the first-stage deheavy tower to provide rising gas of the lower tower; a condenser is arranged at the top of the upper tower of the second-stage delightening tower to provide reflux liquid of the upper tower, and a heater is arranged at the kettle of the lower tower of the second-stage delightening tower to provide rising gas of the lower tower.

[0013] A method for efficiently purifying octafluoropropane, comprising the following steps:

[0014] (1) heating and pressurizing the crude octafluoropropane in the raw material tank;

[0015] (2) The crude gaseous octafluoropropane enters the lower tower of the first de-weighting tower through a feed pipeline, removes heavy component impurities through distillation, and is extracted from the top of the upper tower of the first de-weighting tower; a condenser is arranged on the top of the upper tower of the first de-weighting tower to provide reflux liquid from the upper tower; a heater is arranged in the kettle of the lower tower of the first de-weighting tower to provide ascending gas from the lower tower; the reflux liquid of the lower tower of the first de-weighting tower is provided by a de-weighting reflux pump; the reflux liquid of the upper tower of the first de-weighting tower is refluxed to the lower tower of the first de-weighting tower;

[0016] (3) The octafluoropropane after preliminary purification is extracted from the top of the upper tower of the primary de-heavy tower and enters the upper tower of the secondary de-light tower, where light component impurities are removed by distillation and extracted from the lower tower kettle of the secondary de-light tower; a condenser is arranged on the top of the upper tower of the secondary de-light tower to provide reflux liquid of the upper tower; a heater is arranged in the kettle of the lower tower of the secondary de-light tower to provide ascending gas of the lower tower; the reflux liquid of the lower tower of the secondary de-light tower is provided by a de-light reflux pump; the reflux liquid of the upper tower of the secondary de-light tower is refluxed to the lower tower of the secondary de-light tower;

[0017] (4) After two steps of purification, the octafluoropropane finally enters a three-stage dehydration tower to remove water and obtain electronic grade octafluoropropane gas.

[0018] The main impurities removed by the primary deheaving tower are high-boiling impurities such as hexafluoropropylene, hexafluoropropane and heptafluoropropane. The main impurities removed by the secondary delightening tower are low-boiling impurities such as nitrogen and hexafluoroethane. The main impurities removed by the tertiary dehydration tower are trace amounts of water impurities.

[0019] Furthermore, before purification, the first de-heavy tower upper tower, the first de-heavy tower lower tower, the de-heavy reflux pump, the second de-light tower upper tower, the second de-light tower lower tower, the de-light reflux pump, and the third dehydration tower and its pipelines are purged and replaced. After the entire purification system is tested and qualified, it is pumped to a negative pressure of -0.1 to -0.095MPa.

[0020] Furthermore, the bottom temperature of the first-stage deweighting tower is 10-30°C, the top temperature is -20-20°C, the bottom pressure is 0.2-0.5MPa, the top pressure is 0.2-0.5MPa, and the liquid reflux rate is 400-1000kg / h.

[0021] Further preferably, the bottom temperature of the first deweighting tower is -5-25°C, the top temperature is -15-15°C, the bottom pressure is 0.2-0.4MPa, the top pressure is 0.2-0.4MPa, and the liquid reflux rate of the first deweighting tower is 600-900kg / h.

[0022] Furthermore, the bottom temperature of the secondary light-removal tower is 0-30°C, the top temperature is -5-25°C, the bottom pressure is 0.1-0.4MPa, the top pressure is 0.1-0.4MPa, and the liquid reflux rate is 400-1000kg / h.

[0023] Further preferably, the bottom temperature of the secondary light-removal tower is 5-25°C, the top temperature is 0-20°C, the bottom pressure is 0.2-0.35MPa, the top pressure is 0.2-0.35MPa, and the liquid reflux rate of the secondary light-removal tower is 600-900kg / h.

[0024] Furthermore, the bottom temperature of the three-stage dehydration tower is -5-20°C, the top temperature is -10-15°C, the bottom pressure is 0.15-0.3MPa, and the top pressure is 0.15-0.3MPa.

[0025] Further preferably, the bottom temperature of the three-stage dehydration tower is 5-20°C, the top temperature is 0-15°C, the bottom pressure is 0.15-0.25 MPa, and the top pressure is 0.15-0.25 MPa.

[0026] Furthermore, both the heavy-duty removal reflux pump and the light-duty removal reflux pump are shielded pumps.

[0027] Furthermore, the purity of crude octafluoropropane is 72%-95%, and the purity of electronic grade octafluoropropane gas is 99.999%.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The purification method of the present invention can increase the purity of crude octafluoropropane (content 72%-95%) to more than 99.999% by using a single distillation technology, breaking the inherent combination technology purification process of electronic grade octafluoropropane gas and broadening the purification path of electronic grade octafluoropropane gas.

[0030] 2. The present invention uses a two-stage distillation tower for the removal of heavy and light components from electronic-grade octafluoropropane. While achieving superior separation effects, it effectively reduces the required height of the distillation tower, provides convenience for equipment construction, daily operation, inspection and maintenance, and has obvious practical significance.

[0031] 3. The use of single distillation purification technology is conducive to achieving stable control of product quality. The process is simple, has better operability and economy, and is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the process flow of the present invention.

[0033] In the attached drawings, 1-raw material tank, 2-upper tower of primary deheaving tower, 3-lower tower of primary deheaving tower, 4-heavy deheaving reflux pump, 5-upper tower of secondary deheaving tower, 6-lower tower of secondary deheaving tower, 7-light deheaving reflux pump, 8-tertiary dehydration tower. DETAILED DESCRIPTION

[0034] Equipment Examples

[0035] based on Figure 1 , a device for efficiently purifying octafluoropropane, comprising a raw material tank 1, a first-stage de-heavy tower upper tower 2, a first-stage de-heavy tower lower tower 3, a de-heavy reflux pump 4, a second-stage de-light tower upper tower 5, a second-stage de-light tower lower tower 6, a de-light reflux pump 7 and a third-stage dehydration tower 8; a condenser is arranged on the top of the first-stage de-heavy tower upper tower 2 to provide upper tower reflux liquid, and a heater is arranged on the kettle of the first-stage de-heavy tower lower tower 3 to provide lower tower rising gas; a condenser is arranged on the top of the second-stage de-light tower upper tower 5 to provide upper tower reflux liquid, and a heater is arranged on the kettle of the second-stage de-light tower lower tower 6 to provide lower tower rising gas. A de-heavy reflux pump 4 is arranged on the pipeline between the discharge port of the first-stage de-heavy tower upper tower kettle and the reflux feed port of the first-stage de-light tower lower tower, and a de-light reflux pump 7 is arranged on the pipeline between the discharge port of the second-stage de-light tower upper tower kettle and the reflux feed port of the second-stage de-light tower lower tower.

[0036] The raw material tank 1 is provided with a raw material tank discharge port, the first-stage de-weighting tower lower tower 3 is provided with a first-stage de-weighting tower raw material feed port, a first-stage de-weighting tower lower tower reflux feed port and a first-stage de-weighting tower lower tower top discharge port, the first-stage de-weighting tower upper tower 2 is provided with a first-stage de-weighting tower upper tower feed port, a first-stage de-weighting tower upper tower top discharge port and a first-stage de-weighting tower upper tower kettle discharge port, the second-stage de-lighting tower upper tower 5 is provided with a second-stage de-lighting tower raw material feed port, a second-stage de-lighting tower upper tower feed port and a second-stage de-lighting tower upper tower kettle discharge port, the second-stage de-lighting tower lower tower 6 is provided with a second-stage de-lighting tower lower tower kettle discharge port, a second-stage de-lighting tower lower tower reflux feed port and a second-stage de-lighting tower lower tower top discharge port, the third-stage dehydration tower 8 is provided with a A tertiary dehydration tower raw material feed port and a tertiary dehydration tower discharge port are provided; the raw material tank discharge port is connected to the raw material feed port of the first dehydration tower through a pipeline, the lower tower top discharge port of the first dehydration tower is connected to the upper tower feed port of the first dehydration tower through a pipeline, the upper tower kettle discharge port of the first dehydration tower is connected to the lower tower reflux feed port of the first dehydration tower through a pipeline, the upper tower top discharge port of the first dehydration tower is connected to the raw material feed port of the second de-lightness tower through a pipeline, the upper tower kettle discharge port of the second de-lightness tower is connected to the lower tower reflux feed port of the second de-lightness tower through a pipeline, the lower tower top discharge port of the second de-lightness tower is connected to the upper tower feed port of the second de-lightness tower through a pipeline, and the lower tower kettle discharge port of the second de-lightness tower is connected to the raw material feed port of the tertiary dehydration tower through a pipeline.

[0037] Example 1-5 provides a method for efficiently purifying octafluoropropane, using the equipment of Example 1, the only difference being the operating conditions. The test results are shown in Table 1.

[0038] Example 1

[0039] (1) The first-stage de-heavy tower upper tower 2, the first-stage de-heavy tower lower tower 3, the de-heavy reflux pump 4, the second-stage de-light tower upper tower 5, the second-stage de-light tower lower tower 6, the de-light reflux pump 7 and the third-stage dehydration tower 8 and their pipelines are purged and replaced, and the pressure is maintained for leak detection. After the entire purification system is tested and qualified, it is pumped to a negative pressure of -0.1MPa;

[0040] (2) Wrap the raw material tank 1 with a heating bag with temperature control, turn on the heating, and the raw material is vaporized and pressurized.

[0041] (3) The crude octafluoropropane enters the first de-weighting tower lower tower 3 through the feed pipeline, and the heavy impurities are removed by distillation. The de-weighted octafluoropropane is produced from the top of the first de-weighting tower upper tower 2. The bottom temperature of the first de-weighting tower upper tower 2 and the first de-weighting tower lower tower 3 is 5°C, the top temperature is 0°C, the bottom pressure is 0.305MPa, the top pressure is 0.300MPa, and the liquid reflux rate is 900kg / h.

[0042] (4) The initially purified octafluoropropane is extracted from the top of the primary deheaving tower 2 and enters the secondary delightening tower 5. The light component impurities are removed by distillation, and the delightened octafluoropropane is extracted from the kettle of the secondary delightening tower 6. The kettle temperature of the secondary delightening tower 5 and the secondary delightening tower 6 is 10°C, the top temperature is 5°C, the kettle pressure is 0.255MPa, the top pressure is 0.250MPa, and the liquid reflux rate is 900kg / h.

[0043] (5) After two-step purification, the octafluoropropane enters the tertiary dehydration tower 8 for water removal, and the distillate sample at the top of the tower is tested. After passing the test, the fine octafluoropropane is extracted. The bottom temperature of the tertiary dehydration tower 8 is 5°C, the top temperature is 0°C, the bottom pressure is 0.205MPa, and the top pressure is 0.200MPa.

[0044] Example 2

[0045] (1) The first-stage de-heavy tower upper tower 2, the first-stage de-heavy tower lower tower 3, the de-heavy reflux pump 4, the second-stage de-light tower upper tower 5, the second-stage de-light tower lower tower 6, the de-light reflux pump 7 and the third-stage dehydration tower 8 and their pipelines are purged and replaced, and the pressure is maintained for leak detection. After the entire purification system is tested and qualified, it is pumped to a negative pressure of -0.1MPa;

[0046] (2) Wrap the raw material tank 1 with a heating bag with temperature control, turn on the heating, and the raw material is vaporized and pressurized.

[0047] (3) The crude octafluoropropane enters the lower tower 3 of the first de-weighting tower through the feed pipeline, and the heavy impurities are removed by distillation. The de-weighted octafluoropropane is produced from the top of the upper tower 2 of the first de-weighting tower. The bottom temperature of the upper tower 2 of the first de-weighting tower and the lower tower 3 of the first de-weighting tower is 5°C, the top temperature is 0°C, the bottom pressure is 0.305MPa, the top pressure is 0.300MPa, and the liquid reflux rate is 700kg / h.

[0048] (4) The initially purified octafluoropropane is extracted from the top of the primary deheaving tower 2 and enters the secondary delightening tower 5. The light component impurities are removed by distillation, and the delightened octafluoropropane is extracted from the kettle of the secondary delightening tower 6. The kettle temperature of the secondary delightening tower 5 and the secondary delightening tower 6 is 10°C, the tower top temperature is 5°C, the kettle pressure is 0.255MPa, the tower top pressure is 0.250MPa, and the liquid reflux rate is 700kg / h.

[0049] (5) After two-step purification, the octafluoropropane enters the third-stage dehydration tower to remove water, and the distillate sample at the top of the tower is tested. After passing the test, the fine octafluoropropane is extracted. The bottom temperature of the third-stage dehydration tower 8 is 5°C, the top temperature is 0°C, the bottom pressure is 0.205MPa, and the top pressure is 0.200MPa.

[0050] Example 3

[0051] (1) The first-stage de-heavy tower upper tower 2, the first-stage de-heavy tower lower tower 3, the de-heavy reflux pump 4, the second-stage de-light tower upper tower 5, the second-stage de-light tower lower tower 6, the de-light reflux pump 7 and the third-stage dehydration tower 8 and their pipelines are purged and replaced, and the pressure is maintained for leak detection. After the entire purification system is tested and qualified, it is pumped to a negative pressure of -0.095MPa;

[0052] (2) Wrap the raw material tank 1 with a heating bag with temperature control, turn on the heating, and the raw material is vaporized and pressurized.

[0053] (3) The crude octafluoropropane enters the first de-weighting tower lower tower 3 through the feed pipeline, and the heavy impurities are removed by distillation. The de-weighted octafluoropropane is produced from the top of the first de-weighting tower upper tower 2. The bottom temperature of the first de-weighting tower upper tower 2 and the first de-weighting tower lower tower 3 is 5°C, the top temperature is 0°C, the bottom pressure is 0.325MPa, the top pressure is 0.320MPa, and the liquid reflux rate is 900kg / h.

[0054] (4) The initially purified octafluoropropane is extracted from the top of the primary deheaving tower 3 and enters the secondary delightening tower 5. The light component impurities are removed by distillation, and the delightened octafluoropropane is extracted from the kettle of the secondary delightening tower 6. The kettle temperature of the secondary delightening tower 5 and the secondary delightening tower 6 is 10°C, the top temperature is 5°C, the kettle pressure is 0.255MPa, the top pressure is 0.250MPa, and the liquid reflux rate is 900kg / h.

[0055] (5) After two-step purification, the octafluoropropane enters the tertiary dehydration tower 8 for water removal, and the distillate sample at the top of the tower is tested. After passing the test, the fine octafluoropropane is extracted. The bottom temperature of the tertiary dehydration tower 8 is 5°C, the top temperature is 0°C, the bottom pressure is 0.205MPa, and the top pressure is 0.200MPa.

[0056] Example 4

[0057] (1) The first-stage de-heavy tower upper tower 2, the first-stage de-heavy tower lower tower 3, the de-heavy reflux pump 4, the second-stage de-light tower upper tower 5, the second-stage de-light tower lower tower 6, the de-light reflux pump 7 and the third-stage dehydration tower 8 and their pipelines are purged and replaced, and the pressure is maintained for leak detection. After the entire purification system is tested and qualified, it is pumped to a negative pressure of -0.098MPa;

[0058] (2) Wrap the raw material tank 1 with a heating bag with temperature control, turn on the heating, and the raw material is vaporized and pressurized.

[0059] (3) The crude octafluoropropane enters the first de-weighting tower lower tower 3 through the feed pipeline, and the heavy impurities are removed by distillation. The de-weighted octafluoropropane is produced from the top of the first de-weighting tower upper tower 2. The bottom temperature of the first de-weighting tower upper tower 2 and the first de-weighting tower lower tower 3 is 5°C, the top temperature is 0°C, the bottom pressure is 0.305MPa, the top pressure is 0.300MPa, and the liquid reflux rate is 900kg / h.

[0060] (4) The initially purified octafluoropropane is extracted from the top of the primary deheaving tower 2 and enters the secondary delightening tower 5. The light component impurities are removed by distillation, and the delightened octafluoropropane is extracted from the kettle of the secondary delightening tower 6. The kettle temperature of the secondary delightening tower 5 and the secondary delightening tower 6 is 10°C, the top temperature is 5°C, the kettle pressure is 0.275MPa, the top pressure is 0.270MPa, and the liquid reflux rate is 900kg / h.

[0061] (5) After two-step purification, the octafluoropropane enters the tertiary dehydration tower 8 for water removal, and the distillate sample at the top of the tower is tested. After passing the test, the fine octafluoropropane is extracted. The bottom temperature of the tertiary dehydration tower 8 is 5°C, the top temperature is 0°C, the bottom pressure is 0.205MPa, and the top pressure is 0.200MPa.

[0062] Example 5

[0063] (1) The first-stage de-heavy tower upper tower 2, the first-stage de-heavy tower lower tower 3, the de-heavy reflux pump 4, the second-stage de-light tower upper tower 5, the second-stage de-light tower lower tower 6, the de-light reflux pump 7 and the third-stage dehydration tower 8 and their pipelines are purged and replaced, and the pressure is maintained for leak detection. After the entire purification system is tested and qualified, it is pumped to a negative pressure of -0.1MPa;

[0064] (2) Wrap the raw material tank 1 with a heating bag with temperature control, turn on the heating, and the raw material is vaporized and pressurized.

[0065] (3) The crude octafluoropropane enters the first de-weighting tower lower tower 3 through the feed pipeline, and the heavy impurities are removed by distillation. The de-weighted octafluoropropane is produced from the top of the first de-weighting tower upper tower 2. The bottom temperature of the first de-weighting tower upper tower 2 and the first de-weighting tower lower tower 3 is 5°C, the top temperature is 0°C, the bottom pressure is 0.305MPa, the top pressure is 0.300MPa, and the liquid reflux rate is 900kg / h.

[0066] (4) The initially purified octafluoropropane is extracted from the top of the primary deheaving tower 2 and enters the secondary delightening tower 5. The light component impurities are removed by distillation, and the delightened octafluoropropane is extracted from the kettle of the secondary delightening tower 6. The kettle temperature of the secondary delightening tower 5 and the secondary delightening tower 6 is 10°C, the top temperature is 5°C, the kettle pressure is 0.255MPa, the top pressure is 0.250MPa, and the liquid reflux rate is 900kg / h.

[0067] (5) After two-step purification, the octafluoropropane enters the tertiary dehydration tower 8 for water removal, and the distillate sample at the top of the tower is tested. After passing the test, the fine octafluoropropane is extracted. The bottom temperature of the tertiary dehydration tower 8 is 5°C, the top temperature is 0°C, the bottom pressure is 0.185MPa, and the top pressure is 0.180MPa.

[0068] Table 1 Test results of Examples 1-5

[0069]

[0070] The above descriptions are only five embodiments of the present invention. Any simple modification or replacement based on the present invention is within the protection scope of the present invention.

Claims

1. A device for efficiently purifying octafluoropropane, characterized in that: Including raw material tank, first-stage de-heavy tower upper tower, first-stage de-heavy tower lower tower, de-heavy reflux pump, second-stage de-light tower upper tower, second-stage de-light tower lower tower, de-light reflux pump and third-stage dehydration tower; The raw material tank is provided with a raw material tank discharge port, the lower tower of the first-level de-weighting tower is provided with a raw material feed port of the first-level de-weighting tower, a reflux feed port of the lower tower of the first-level de-weighting tower and a top discharge port of the lower tower of the first-level de-weighting tower, the upper tower of the first-level de-weighting tower is provided with a feed port of the upper tower of the first-level de-weighting tower, a top discharge port of the upper tower of the first-level de-weighting tower and a discharge port of the upper kettle of the first-level de-weighting tower, the upper tower of the second-level de-lighting tower is provided with a raw material feed port of the second-level de-lighting tower, a feed port of the upper tower of the second-level de-lighting tower and a discharge port of the upper kettle of the second-level de-lighting tower, the lower tower of the second-level de-lighting tower is provided with a discharge port of the lower kettle of the second-level de-lighting tower, a reflux feed port of the lower tower of the second-level de-lighting tower and a top discharge port of the lower tower of the second-level de-lighting tower, and the third-level de-watering tower is provided with a raw material feed port of the third-level de-watering tower and a discharge port of the third-level de-watering tower; The discharge port of the raw material tank is connected to the raw material feed port of the first-stage de-weighting tower through a pipeline, the discharge port of the lower tower top of the first-stage de-weighting tower is connected to the feed port of the upper tower of the first-stage de-weighting tower through a pipeline, the discharge port of the upper tower kettle of the first-stage de-weighting tower is connected to the reflux feed port of the lower tower of the first-stage de-weighting tower through a pipeline, the upper tower top discharge port of the first-stage de-weighting tower is connected to the raw material feed port of the second-stage de-lighting tower through a pipeline, the upper tower kettle discharge port of the second-stage de-lighting tower is connected to the reflux feed port of the lower tower of the second-stage de-lighting tower through a pipeline, the lower tower top discharge port of the second-stage de-lighting tower is connected to the feed port of the upper tower of the second-stage de-lighting tower through a pipeline, and the lower tower kettle discharge port of the second-stage de-lighting tower is connected to the raw material feed port of the tertiary dehydration tower through a pipeline.

2. The device for efficiently purifying octafluoropropane according to claim 1, characterized in that: A de-heavy reflux pump is provided on the pipeline between the discharge port of the upper kettle of the first de-heavy tower and the reflux feed port of the lower tower of the first de-heavy tower, and a de-light reflux pump is provided on the pipeline between the discharge port of the upper kettle of the second de-light tower and the reflux feed port of the lower tower of the second de-light tower.

3. The device for efficiently purifying octafluoropropane according to claim 1, characterized in that: A condenser is arranged at the top of the upper tower of the first-stage deheavy tower to provide reflux liquid for the upper tower, and a heater is arranged at the kettle of the lower tower of the first-stage deheavy tower to provide rising gas for the lower tower; a condenser is arranged at the top of the upper tower of the second-stage delightening tower to provide reflux liquid for the upper tower, and a heater is arranged at the kettle of the lower tower of the second-stage delightening tower to provide rising gas for the lower tower.

4. A method for efficiently purifying octafluoropropane, using the device for efficiently purifying octafluoropropane according to any one of claims 1 to 3, characterized in that: The specific steps are as follows: (1) heating and pressurizing the crude octafluoropropane in the raw material tank; (2) The crude gaseous octafluoropropane enters the lower tower of the first de-weighting tower through the feed pipeline, removes the heavy component impurities through distillation, and is extracted from the top of the upper tower of the first de-weighting tower; the reflux liquid of the upper tower of the first de-weighting tower is refluxed to the lower tower of the first de-weighting tower; (3) The initially purified octafluoropropane is extracted from the top of the first heavy removal tower and enters the second light removal tower. The light component impurities are removed by distillation and then extracted from the bottom kettle of the second light removal tower. The reflux liquid of the second light removal tower is refluxed to the bottom tower of the second light removal tower. (4) After two steps of purification, the octafluoropropane finally enters a three-stage dehydration tower to remove water and obtain electronic grade octafluoropropane gas.

5. A method for efficiently purifying octafluoropropane as claimed in claim 4, characterized in that: Before purification, the upper tower of the first-stage deheavy removal tower, the lower tower of the first-stage deheavy removal tower, the deheavy removal reflux pump, the upper tower of the second-stage deheavy removal tower, the lower tower of the second-stage deheavy removal tower, the deheavy removal reflux pump and the tertiary dehydration tower and its pipelines are purged and replaced. After the entire purification system is tested and qualified, it is pumped to a negative pressure of -0.1 to -0.095MPa.

6. A method for efficiently purifying octafluoropropane as claimed in claim 4, characterized in that: The bottom temperature of the first-stage deweighting tower is 10-30°C, the top temperature is -20-20°C, the bottom pressure is 0.2-0.5MPa, the top pressure is 0.2-0.5MPa, and the liquid reflux rate is 400-1000kg / h.

7. A method for efficiently purifying octafluoropropane as claimed in claim 4, characterized in that: The bottom temperature of the secondary light-removal tower is 0-30°C, the top temperature is -5-25°C, the bottom pressure is 0.1-0.4MPa, the top pressure is 0.1-0.4MPa, and the liquid reflux rate is 400-1000kg / h.

8. A method for efficiently purifying octafluoropropane as claimed in claim 4, characterized in that: The bottom temperature of the three-stage dehydration tower is -5-20°C, the top temperature is -10-15°C, the bottom pressure is 0.15-0.3MPa, and the top pressure is 0.15-0.3MPa.

9. A method for efficiently purifying octafluoropropane as claimed in claim 4, characterized in that: Both the heavy-weight removal reflux pump and the light-weight removal reflux pump are shielded pumps.

10. The method for efficiently purifying octafluoropropane according to claim 1, characterized in that: The purity of crude octafluoropropane is 72%-95%, and the purity of electronic grade octafluoropropane gas is 99.999%.

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