Propyne alcohol purification system and process based on heat pump rectification

Abstract

This invention belongs to the field of fine chemical production processes and discloses a propynyl alcohol purification system and process based on heat pump distillation. It utilizes heat pump distillation technology to achieve internal heat circulation, working in conjunction with a de-weighting tower, flash tank, azeotropic distillation tower, and refining tower to form a complete and efficient propynyl alcohol purification system. First, the mixture containing propynyl alcohol is filtered to remove water-insoluble organic impurities and precipitated inorganic salts. Then, water, high-boiling-point organic impurities, and inorganic salts are removed by distillation in the de-weighting tower, while low-boiling-point organic impurities are removed by temperature-controlled flash tank. Subsequently, an azeotropic distillation tower is used to efficiently remove water by adding an azeotropic agent, yielding propynyl alcohol with low water content. Finally, low-pressure distillation in the refining tower yields high-purity propynyl alcohol with a water content of less than 1 wt%. This invention effectively protects propynyl alcohol from thermal deterioration, breaks the azeotropic system, and combines the advantages of efficient water removal, energy saving, reduced equipment corrosion, and continuous and high-yield propynyl alcohol purification.

Description

Technical Field

[0001] This invention relates to the field of fine chemical production processes, specifically to a propynyl alcohol purification system and process based on heat pump distillation. Background Technology

[0002] Propynol, also known as 2-propyn-1-ol or propynyl alcohol, is the simplest alkynol compound. It is a volatile liquid at room temperature, exhibiting high reactivity and a high boiling point (approximately 114°C). It is miscible with many polar solvents such as water, ethanol, and acetone, making it an important organic intermediate. However, existing reaction systems for preparing propynol often result in a product system containing a large amount of water, and propynol exhibits an azeotropic reaction with water. Traditional simple distillation is insufficient for effectively removing water during the purification of propynol.

[0003] The existing separation technology mainly faces the following problems: (1) High heat sensitivity: propynol will deteriorate rapidly at temperatures above 100°C, affecting the quality of the final product and limiting the upper limit of the dehydration process; (2) Difficult to separate azeotropic systems: when water is used as an azeotropic agent to azeotropically with propynol, the water content is high, and the two phases are difficult to separate completely; (3) High cost of traditional extraction: physical extraction requires the use of high-boiling-point extractants and strict control of water content, resulting in high costs.

[0004] Patent CN107032956A discloses a method for preparing propynyl alcohol. The purification method of propynyl alcohol is as follows: after adding the azeotropic agent isopropyl ether to the crude propynyl alcohol, it is azeotropically dehydrated at 62°C using a fractionating column with a theoretical plate number of 4 until the resulting condensate does not separate into layers. The remaining liquid after azeotropic dehydration is fractionated using a fractionating column with a theoretical plate number of 10, with the reflux ratio controlled at 2:1. The fraction at 112-115°C is collected to obtain high-purity propynyl alcohol. However, this method does not solve the problem of heat sensitivity, and the theoretical plate number and reflux ratio used are small, resulting in propynyl alcohol at the top of the column, which affects the separation effect.

[0005] Therefore, there is an urgent need for a process that can overcome the heat sensitivity of propynyl alcohol, achieve efficient water removal, reduce energy consumption, and minimize equipment corrosion. Summary of the Invention

[0006] To address the problems of high heat sensitivity of propynyl alcohol, difficulty in separating it from water in an azeotropic system, and high cost of traditional extraction in existing technologies, this invention provides a propynyl alcohol purification system and process based on heat pump distillation. Utilizing heat pump distillation technology to achieve internal heat circulation, it works in conjunction with a de-weighting tower, flash tank, azeotropic distillation tower, and refining tower to form a complete and efficient propynyl alcohol purification system. First, the mixture containing propynyl alcohol is filtered to remove water-insoluble organic impurities and precipitated inorganic salts. Then, water, high-boiling-point organic impurities, and inorganic salts are removed by distillation in the de-weighting tower, while low-boiling-point organic impurities are removed by temperature-controlled flash tank. Subsequently, an azeotropic distillation column is used to efficiently remove water by adding an azeotropic agent, yielding propynyl alcohol with low water content. Finally, low-pressure distillation in the refining tower yields high-purity propynyl alcohol with a water content of less than 1 wt%, achieving efficient separation of propynyl alcohol while significantly reducing energy consumption.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A propynyl alcohol purification system based on heat pump distillation, the purification system mainly includes a centrifuge, a deweighting tower, a flash tank, an azeotropic distillation tower, a layered tank, a refining tower, a compressor, a heat exchanger, and a reboiler.

[0008] The centrifuge filters the mixture containing propynyl alcohol to remove water-insoluble organic impurities and precipitated inorganic salts. The filtrate is then heated by a transfer pump and two heat exchangers before entering the deweighting tower.

[0009] The de-weighting tower receives filtrate from the centrifuge in its middle section to remove water, high-boiling-point organic impurities, and inorganic salts. The treated mixture containing propynyl alcohol is discharged from the top of the tower into a flash tank. A reboiler is installed at the bottom of the tower to provide heat energy for the de-weighting tower. Furthermore, the distillate from the top of the de-weighting tower is heated by a compressor, then transferred to the feed of the de-weighting tower via a heat exchanger. After being cooled by another heat exchanger, one stream returns to the top of the tower, while the other enters the flash tank. The bottom components of the de-weighting tower can further provide heat to the heat exchanger on the centrifuge discharge line. This effectively achieves internal energy recovery from the top and bottom of the tower, reducing the need for external heating and lowering energy consumption.

[0010] The lower part of the flash tank receives a mixture containing propynyl alcohol from the de-weighting tower to remove low-boiling-point organic impurities. The top is provided with a low-boiling-point impurity outlet. After treatment, the resulting propynyl alcohol aqueous solution is discharged from the lower part of the flash tank and enters the azeotropic distillation tower.

[0011] The middle section of the azeotropic distillation column receives propargyl alcohol aqueous solution from the flash tank for efficient dehydration. The azeotropic agent enters from the top of the column. The distillate from the top of the azeotropic distillation column is heated by a compressor, and then the heat is transferred to the azeotropic agent through a heat exchanger. After being cooled by another heat exchanger, one stream flows back to the top of the column, and the other stream enters the separator, thus achieving internal energy recovery and utilization. The lower part of the separator separates out water, and the upper part separates out the azeotropic agent, which is pumped back into the column for recycling. A reboiler is installed at the bottom of the column to provide heat energy for the azeotropic distillation column. The dehydrated propargyl alcohol aqueous solution is discharged from the bottom of the column and enters the purification column.

[0012] The middle section of the refining column receives propargyl alcohol aqueous solution from the azeotropic distillation column. High-purity propargyl alcohol is obtained through further low-pressure distillation. The distillate from the top of the column is cooled by a heat exchanger and then refluxed back to the top of the column, while transferring heat to the feed of the flash tank, thus realizing energy recovery and utilization. A reboiler is installed at the bottom of the column to provide heat energy for the refining column.

[0013] It is worth noting that this invention relates to a mixture containing propynyl alcohol obtained after the reaction is completed in the preparation process of propynyl alcohol in the prior application CN119569537A. The mixture mainly contains propynyl alcohol, water, organic impurities, and inorganic salts, wherein the content of propynyl alcohol is 2-10 wt%, the content of water is 20-80 wt%, and the balance is organic impurities and inorganic salts.

[0014] The organic impurities are divided into water-insoluble organic impurities, high-boiling-point organic impurities, and low-boiling-point organic impurities. The water-insoluble organic impurities are tar, the high-boiling-point organic impurities are the intermediate 3-chloroprop-2-en-1-ol and phase transfer catalysts, among which the phase transfer catalysts are dodecylmethylammonium chloride, trioctylmethylammonium chloride or trioctylmethylammonium bromide, the low-boiling-point organic impurities are 3-chloropropene, and the inorganic salts are sodium hydroxide or potassium hydroxide.

[0015] The present invention also provides a propynyl alcohol purification process based on heat pump distillation, wherein the process uses the above-mentioned purification system, and the specific steps are as follows: (1) Removal and pretreatment: The mixture containing propynyl alcohol is cooled and then filtered by a centrifuge to remove water-insoluble organic impurities and inorganic salts. The filtrate is then pumped by a transfer pump and successively heated in two heat exchangers before entering the deweighting tower. The mixture containing propynyl alcohol described in step (1) is cooled to -5 to 30°C to allow inorganic salts to precipitate. The centrifuge operates at a speed of 1000-5000 rpm, and the heating temperature is 30-100℃.

[0016] (2) Removal of impurities and water in the de-weighting tower: The de-weighting tower distillation removes water, high-boiling-point organic impurities, and inorganic salts from the filtrate discharged from the centrifuge. The reboiler at the bottom of the tower provides heat energy for the de-weighting tower. After being heated by the compressor, the distillate from the top of the tower first transfers heat to the feed of the de-weighting tower through a heat exchanger, and then is cooled to 0-30℃ through another heat exchanger. One stream returns to the top of the tower, while the other stream enters the flash tank. After removing impurities and water in the de-weighting tower, a propynyl alcohol aqueous solution with a water content of 30-60wt% is obtained and enters the flash tank. The theoretical number of trays in the de-weighting tower described in step (2) is 10-30, the operating pressure is 0-150 kPa, preferably 10-30 kPa, the top temperature is 50-70℃, the bottom temperature is 65-80℃, and the reflux ratio is 1-4.

[0017] The feed location for the deweighting tower is at trays 5-15.

[0018] The compressor has an outlet pressure of 70-100 kPa and an outlet temperature of 70-100 °C.

[0019] (3) Flash tank impurity removal: The propynyl alcohol aqueous solution discharged from the de-weighting tower enters the flash tank for impurity removal. Low-boiling-point impurities evaporate from the top of the flash tank, and the purified propynyl alcohol aqueous solution enters the azeotropic distillation tower. The operating pressure of the flash tank in step (3) is atmospheric pressure, and the operating temperature is 40-80℃.

[0020] (4) Dehydration of the azeotropic distillation column: The propynyl alcohol aqueous solution from the flash tank enters from the middle of the azeotropic distillation column, and the azeotropic agent enters from the top of the azeotropic distillation column. After the top distillate is heated by the compressor, it first transfers heat to the azeotropic agent through a heat exchanger, and then cools down to 0-30℃ through another heat exchanger. One stream returns to the top of the column, and the other stream enters the separator. The water is separated from the bottom of the separator, and the azeotropic agent separated from the top is pumped back into the column for recycling. A reboiler is installed at the bottom of the column to provide heat energy for the azeotropic distillation column. After dehydration, the propynyl alcohol aqueous solution with a water content of 1-10wt% is obtained and discharged from the bottom of the column into the purification column. The theoretical number of plates in the azeotropic distillation column described in step (4) is 15-35, the operating pressure is 0-70 kPa, the top temperature is 20-60℃, and the reflux ratio is 1-5.

[0021] The feed location for the azeotropic distillation column is at trays 7-17.

[0022] The compressor has an outlet pressure of 70-200 kPa and an outlet temperature of 60-90℃.

[0023] The azeotropic agent is one of toluene, cyclohexane, and isopropyl ether, and the mass ratio of the azeotropic agent to the water in the feed is 5-20:1.

[0024] (5) Refining column distillation: The propynyl alcohol aqueous solution from the azeotropic distillation column is further dehydrated in the refining column. The distillate from the top of the column is cooled to 0-30℃ by a heat exchanger and returned to the top of the column, while transferring heat to the feed of the flash tank. A reboiler is installed at the bottom of the column to provide heat energy for the refining column. After distillation, high-purity propynyl alcohol with a water content of less than 1wt% is obtained.

[0025] The theoretical number of trays in the refining column described in step (5) is 10-40, the operating pressure is 0-70 kPa, the top temperature is 50-100℃, and the reflux ratio is 2-5.

[0026] The feed point for the refining tower is located at trays 5-30.

[0027] Compared with the prior art, the technical effects achieved by the present invention are as follows: (1) The purification system provided by the present invention uses heat pump distillation technology. The compressor converts the low-grade heat of the top distillate of the de-weighting tower / azeotropic distillation tower into a high-grade heat source, realizing the heat exchange between the top reflux component and the component in the tower. Through the internal heat integration of the system, the heat inside the system is fully utilized, reducing the consumption of external utilities.

[0028] (2) The present invention further selects a low-boiling-point, non-polar azeotropic agent to break the azeotropic system of propynyl alcohol and water, achieve efficient water removal and reduce the risk of corrosion, and remove impurities through filtration and distillation to obtain an efficient and energy-saving treatment solution.

[0029] (3) The processing technology provided by the present invention adopts low-pressure operation, and the overall system temperature is lower than the boiling point of propynol, which can protect propynol from thermal deterioration, ensure product quality, break the azeotropic system, and has the advantages of efficient water removal, energy saving and consumption reduction, and reduced equipment corrosion, thus realizing the continuous and high yield of propynol purification. Attached Figure Description

[0030] Figure 1 This is a simplified flowchart of the present invention.

[0031] In the diagram, 1 is a centrifuge, 2 is a transfer pump a, 3 is a heat exchanger a, 4 is a heat exchanger b, 5 is a deweighting tower, 6 is a compressor a, 7 is a heat exchanger c, 8 is a reboiler a, 9 is a flash tank, 10 is an azeotropic distillation tower, 11 is a compressor b, 12 is a heat exchanger d, 13 is a heat exchanger e, 14 is a stratification tank, 15 is a transfer pump b, 16 is a reboiler b, 17 is a refining tower, 18 is a heat exchanger f, and 19 is a reboiler c. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to specific embodiments. These embodiments are only used to illustrate the technical solution of the present invention in more detail and should not be construed as limiting the scope of protection of the present invention.

[0033] A propynyl alcohol purification system based on heat pump distillation, the purification system mainly includes a centrifuge 1, a deweighting tower 5, a flash tank 9, an azeotropic distillation tower 10, a layered tank 14, a refining tower 17, compressors a / b, heat exchangers a / b / c / d / e / f, and reboilers a / b / c.

[0034] Centrifuge 1 filters the mixture containing propynyl alcohol to remove water-insoluble organic impurities and precipitated inorganic salts. The filtrate is then heated by transfer pump a 2, heat exchanger a 3, and heat exchanger b 4 before entering the deweighting tower 5.

[0035] The middle section of the de-weighting tower 5 receives the filtrate from the centrifuge 1 and is used to remove water, high-boiling-point organic impurities and inorganic salts. The treated mixture containing propynyl alcohol is discharged from the top of the tower into the flash tank 9. At the same time, a reboiler a8 is installed at the bottom of the tower to provide heat energy for the de-weighting tower 5.

[0036] Furthermore, after being heated by compressor a6, the distillate from the top of the de-weighting tower 5 first transfers heat to the feed of the de-weighting tower 5 through heat exchanger b4, and then is cooled by heat exchanger c7 before flowing back to the top of the tower in one direction and into flash tank 9 in the other. The bottom components of the de-weighting tower 5 can further provide heat to heat exchanger a3 on the discharge pipeline of centrifuge 1. This effectively realizes the internal recovery of energy from the top and bottom of the tower, reduces the need for external heating, and lowers energy consumption.

[0037] The lower part of the flash tank 9 receives a mixture containing propynyl alcohol from the de-weighting tower 5 to remove low-boiling-point organic impurities. The top is provided with a low-boiling-point impurity outlet. After treatment, the propynyl alcohol aqueous solution is discharged from the lower part of the flash tank 9 and enters the azeotropic distillation tower 10.

[0038] The middle section of the azeotropic distillation column 10 receives propynyl alcohol aqueous solution from flash tank 9 for efficient dehydration. The azeotropic agent enters from the top of the column. The distillate from the top of the azeotropic distillation column 10 is heated by compressor b 11, and then the heat is transferred to the azeotropic agent through heat exchanger d 12. After being cooled by heat exchanger e 13, one stream flows back to the top of the column, and the other stream enters the separator 14, thus realizing internal energy recovery and utilization. The lower part of the separator 14 separates out water, and the upper part of the separated azeotropic agent is pumped back into the column by transfer pump b 15 for recycling. A reboiler b 16 is installed at the bottom of the column to provide heat energy for the azeotropic distillation column 10. The dehydrated propynyl alcohol aqueous solution is discharged from the bottom of the column and enters the purification column 17.

[0039] The middle section of the refining column 17 receives a propynyl alcohol aqueous solution from the azeotropic distillation column 10. High-purity propynyl alcohol is obtained through further low-pressure distillation. The distillate from the top of the column is cooled by heat exchanger f 18 and then refluxed back to the top of the column, while transferring heat to the feed of the flash tank 9 to achieve energy recovery and utilization. A reboiler c 19 is installed at the bottom of the column to provide heat energy for the refining column 17.

[0040] The following examples use the purification system described above to purify the propargyl alcohol-containing mixture obtained after the reaction in the preparation process of propargyl alcohol in the prior application CN119569537A. The following examples process the same batch of material.

[0041] Example 1: A propynyl alcohol purification system and process based on heat pump distillation (1) Impurity removal and pretreatment: The mixture containing propynyl alcohol is cooled to 20°C and then filtered through centrifuge 1 to remove water-insoluble organic impurities and inorganic salts. The rotation speed is 2000 rpm, and the filtrate accounts for 4% of the total weight. The filtrate is lifted by transfer pump a 2 and then enters heat exchanger a 3 and heat exchanger b 4 in sequence to be heated to 70°C before entering the deweighting tower 5. (2) Removal of impurities and water in the de-weighting tower: Subsequently, water, high-boiling-point organic impurities and inorganic salts are removed by distillation in the de-weighting tower 5. The de-weighting tower 5 has 15 trays, the feed position is at the 7th tray, the reflux ratio is 2, and the reboiler a 8 at the bottom of the tower provides heat energy to the de-weighting tower 5. The de-weighting tower 5 is controlled at a pressure of 50 kPa, the top temperature is 65℃, and the bottom temperature is 72℃. The distillate at the top of the tower is compressed to 100 kPa and the temperature is 95℃ by the compressor a 6. The heat is first transferred to the feed of the de-weighting tower 5 through the heat exchanger b 4, and then cooled to 0-10℃ through the heat exchanger c 7. One stream is refluxed back to the top of the tower, and the other stream enters the flash tank 9. After removing impurities and water in the de-weighting tower 5, a propynyl alcohol solution with 43 wt% water is obtained. (3) Flash tank impurity removal: The propynyl alcohol aqueous solution discharged from the de-weighting tower 5 enters the flash tank 9 for impurity removal. The flash tank 9 is operated at atmospheric pressure and the operating temperature is 60℃. Low boiling point impurities evaporate from the top of the flash tank 9 to obtain a propynyl alcohol solution with 42wt% water, which enters the azeotropic distillation tower 10. (4) Dehydration of the azeotropic distillation column: The azeotropic distillation column 10 has 20 trays, an operating pressure of 30 kPa, a top temperature of 30°C, and a reflux ratio of 2. The propynyl alcohol aqueous solution from the flash tank 9 enters from the 10th tray of the azeotropic distillation column 10. The azeotropic agent cyclohexane enters from the top of the azeotropic distillation column 10. The mass ratio of cyclohexane to water in the feed is 10:1. A reboiler b 16 is installed at the bottom of the column to provide heat energy for the azeotropic distillation column 10. The distillate from the top of the column is compressed to 130 kPa and 70°C by the compressor b 11. The heat is first transferred to the azeotropic agent through the heat exchanger d 12, and then cooled to 0-10°C through the heat exchanger e 13. One stream returns to the top of the column, and the other stream enters the separator 14. Water is separated from the bottom of the separator 14, and the cyclohexane separated from the top is transferred to the top by the transfer pump b. 15 is returned to the tower for recycling; after dehydration, a 4.3wt% propynyl alcohol aqueous solution is obtained and discharged from the bottom of the tower into the refining tower 17; (5) Refining column distillation: The refining column has 25 trays, an operating pressure of 30 kPa, a top temperature of 70°C, and a reflux ratio of 3. The propynyl alcohol aqueous solution from the azeotropic distillation column 10 enters from the 13th tray of the refining column 17. The top distillate is cooled to 0-10°C by the heat exchanger f 18 and then refluxed back to the top of the column, while transferring heat to the feed of the flash tank 9. A reboiler c 19 is installed at the bottom of the column to provide heat energy for the refining column 17. By utilizing the high reflux ratio, the aqueous phase is enriched at the top of the column, and the bottom liquid is propynyl alcohol with a water content of 0.83 wt%.

[0042] Example 2: A propynyl alcohol purification system and process based on heat pump distillation (1) Impurity removal and pretreatment: The mixture containing propynyl alcohol is cooled to 20°C and then filtered through centrifuge 1 to remove water-insoluble organic impurities and inorganic salts. The rotation speed is 2000 rpm, and the filtrate accounts for 4% of the total weight. The filtrate is lifted by transfer pump a 2 and then enters heat exchanger a 3 and heat exchanger b 4 in sequence to be heated to 70°C before entering the deweighting tower 5. (2) Removal of impurities and water in the de-weighting tower: Water, high-boiling-point organic impurities and inorganic salts are then removed by distillation in the de-weighting tower 5. The de-weighting tower 5 has 15 trays, the feed position is at the 7th tray, the reflux ratio is 2, and the reboiler a 8 at the bottom of the tower provides heat energy to the de-weighting tower 5. The pressure of the de-weighting tower 5 is controlled at 70 kPa, the top temperature is 66℃, and the bottom temperature is 80℃. The distillate at the top of the tower is compressed to 100 kPa and the temperature is 95℃ by the compressor a 6. The heat is first transferred to the feed of the de-weighting tower 5 through the heat exchanger b 4, and then cooled to 0-10℃ through the heat exchanger c 7. One stream returns to the top of the tower, and the other stream enters the flash tank 9. After removing impurities and water in the de-weighting tower 5, a propynyl alcohol solution with 44 wt% water is obtained. (3) Flash tank impurity removal: The propynyl alcohol aqueous solution discharged from the de-weighting tower 5 enters the flash tank 9 for impurity removal. The flash tank 9 is operated at atmospheric pressure and the operating temperature is 70℃. Low boiling point impurities evaporate from the top of the flash tank 9 to obtain a propynyl alcohol solution with 44wt% water, which enters the azeotropic distillation tower 10. (4) Dehydration of the azeotropic distillation column: The azeotropic distillation column has 20 trays, an operating pressure of 30 kPa, a top temperature of 30°C, and a reflux ratio of 2. The propynyl alcohol aqueous solution from flash tank 9 enters from the 10th tray of the azeotropic distillation column 10. The azeotropic agent cyclohexane enters from the top of the azeotropic distillation column 10. The mass ratio of cyclohexane to water in the feed is 10:1. A reboiler b 16 is installed at the bottom of the column to provide heat energy for the azeotropic distillation column 10. The distillate from the top of the column is compressed to 130 kPa and 70°C by compressor b 11. The heat is first transferred to the azeotropic agent through heat exchanger d 12, and then cooled to 0-10°C through heat exchanger e 13. One stream returns to the top of the column, and the other stream enters the separator 14. Water is separated from the bottom of the separator 14, and the cyclohexane separated from the top is transferred to pump b 15 is returned to the tower for recycling; after dehydration, a 5.7wt% propynyl alcohol aqueous solution is obtained and discharged from the bottom of the tower into the refining tower 17; (5) Refining column distillation: The number of trays in the refining column is 25, the operating pressure is 30 kPa, the top temperature is 70℃, and the reflux ratio is 4. The propynyl alcohol aqueous solution from the azeotropic distillation column 10 enters from the 13th tray of the refining column 17. The top distillate is cooled to 0-10℃ by the heat exchanger f 18 and then refluxed back to the top of the column, while transferring heat to the feed of the flash tank 9. A reboiler c 19 is installed at the bottom of the column to provide heat energy for the refining column 17. By utilizing the high reflux ratio, the aqueous phase is enriched at the top of the column, and the bottom liquid is propynyl alcohol with a water content of 0.94 w%.

[0043] Based on Example 2, the inventors further compared the effects of different top pressures on the water content of propargyl alcohol in step (2), as shown in Table 1 below. The data in the table show that as the top pressure of the de-weighting tower decreases, the water content of propargyl alcohol decreases, and the pressure range is further preferably 10-30 kPa.

[0044] Table 1. Effect of different top pressures of the dehydration tower on the water content of propargyl alcohol. .

[0045] Example 3: A propynyl alcohol purification system and process based on heat pump distillation (1) Impurity removal and pretreatment: The mixture containing propynyl alcohol is cooled to 20°C and then filtered through centrifuge 1 to remove water-insoluble organic impurities and inorganic salts. The rotation speed is 2000 rpm, and the filtrate accounts for 4% of the total weight. The filtrate is lifted by transfer pump a 2 and then enters heat exchanger a 3 and heat exchanger b 4 in sequence to be heated to 70°C before entering the deweighting tower 5. (2) Removal of impurities and water in the de-weighting tower: Subsequently, water, high-boiling-point organic impurities and inorganic salts are removed by distillation in the de-weighting tower 5. The de-weighting tower 5 has 20 trays, the feed position is at the 10th tray, the reflux ratio is 2, and the reboiler a 8 at the bottom of the tower provides heat energy to the de-weighting tower 5. The pressure of the de-weighting tower 5 is controlled at 30 kPa, the top temperature is 62℃, the bottom temperature is 70℃, and the top distillate is compressed to 80 kPa and 90℃ by the compressor a 6. The heat is first transferred to the feed of the de-weighting tower 5 through the heat exchanger b 4, and then cooled to 0-10℃ through the heat exchanger c 7. One stream returns to the top of the tower, and the other stream enters the flash tank 9. After removing impurities and water in the de-weighting tower 5, a propynyl alcohol solution with 40 wt% water is obtained. (3) Flash tank impurity removal: The propynyl alcohol aqueous solution discharged from the de-weighting tower 5 enters the flash tank 9 for impurity removal. The flash tank 9 is operated at atmospheric pressure and the operating temperature is 70℃. Low boiling point impurities evaporate from the top of the flash tank 9 to obtain a propynyl alcohol solution with a water content of 39wt%, which enters the azeotropic distillation tower 10. (4) Dehydration of the azeotropic distillation column: The azeotropic distillation column has 25 trays, an operating pressure of 20 kPa, a top temperature of 28°C, and a reflux ratio of 2. The propynyl alcohol aqueous solution from flash tank 9 enters from the 12th tray of the azeotropic distillation column 10. The azeotropic agent toluene enters from the top of the azeotropic distillation column 10. The mass ratio of toluene to water in the feed is 20:1. A reboiler b16 is installed at the bottom of the column to provide heat energy for the azeotropic distillation column 10. The distillate from the top of the column is compressed to 130 kPa and 70°C by compressor b11. The heat is first transferred to the azeotropic agent through heat exchanger d12, and then cooled to 0-10°C through heat exchanger e13. One stream returns to the top of the column, and the other stream enters the separator 14. Water is separated from the bottom of the separator 14, and cyclohexane separated from the top is transferred to pump b14. 15 is returned to the tower for recycling; after dehydration, a 2.8% (w%) propynyl alcohol aqueous solution is obtained and discharged from the bottom of the tower into the refining tower 17; (5) Refining column distillation: The number of trays in the refining column is 25, the operating pressure is 30 kPa, the top temperature is 70 °C, and the reflux ratio is 5. The propynyl alcohol aqueous solution from the azeotropic distillation column 10 enters from the 12th tray of the refining column. The top distillate is cooled to 0-10 °C by heat exchanger f 18 and then refluxed back to the top of the column, while transferring heat to the feed of flash tank 9. A reboiler c 19 is installed at the bottom of the column to provide heat energy for the refining column 17. By utilizing the high reflux ratio, the aqueous phase is enriched at the top of the column, and the bottom liquid is propynyl alcohol with a water content of 0.37 w%.

[0046] Based on step (2) of Example 3, the present invention further compared the effect of the addition multiple of azeotropic agent on the water content of propargyl alcohol, as shown in Table 2 below. It can be seen that as the amount of azeotropic agent added increases, the water content of propargyl alcohol after treatment in the azeotropic distillation column decreases. However, increasing the amount of azeotropic agent will increase the cost. Therefore, the mass ratio of azeotropic agent to water in the feed is controlled at 5-20:1.

[0047] Table 2. Effect of different azeotropic agent addition ratios on propargyl alcohol water content. .

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any equivalent substitutions or modifications made by those skilled in the art within the spirit and principle of the present invention without any creative effort should be included within the protection scope of the present invention.

Claims

1. A propynyl alcohol purification system based on heat pump distillation, characterized in that, The purification system mainly includes a centrifuge, a deweighting tower, a flash tank, an azeotropic distillation tower, a layered tank, a refining tower, a compressor, a heat exchanger, and a reboiler; The centrifuge filters the mixture containing propynyl alcohol, and the filtrate is then heated by a transfer pump and two heat exchangers before entering the deweighting tower. The de-heavy column receives filtrate from the centrifuge in its middle section. The treated mixture containing propynyl alcohol is discharged from the top of the column into a flash tank, while a reboiler is installed at the bottom of the column. The distillate from the top of the de-heavy column is heated by a compressor, and then the heat is transferred to the feed of the de-heavy column through a heat exchanger. After being cooled by another heat exchanger, one stream flows back to the top of the column, and the other stream flows into the flash tank. The bottom component of the de-heavy column provides heat to the heat exchanger on the centrifuge discharge line. The lower part of the flash tank receives a mixture containing propynyl alcohol from the de-weighting tower, and the top is provided with a low-boiling-point impurity outlet. After processing, the resulting propynyl alcohol aqueous solution is discharged from the lower part of the flash tank and enters the azeotropic distillation tower. The middle section of the azeotropic distillation column receives propargyl alcohol aqueous solution from the flash tank. The azeotropic agent enters from the top of the column. The distillate from the top of the azeotropic distillation column is heated by a compressor, and then the heat is transferred to the azeotropic agent through a heat exchanger. After being cooled by another heat exchanger, one stream flows back to the top of the column, and the other stream enters the separator. Water is separated from the bottom of the separator, and the azeotropic agent separated from the top is pumped back into the column. A reboiler is installed at the bottom of the column, and the propargyl alcohol aqueous solution after water removal is discharged from the bottom of the column and enters the refining column. The middle section of the refining column receives a propargyl alcohol aqueous solution from the azeotropic distillation column. High-purity propargyl alcohol is obtained through further low-pressure distillation. The distillate from the top of the column is cooled by a heat exchanger and then refluxed back to the top of the column, while transferring heat to the feed of the flash tank. A reboiler is installed at the bottom of the column.

2. A propynyl alcohol purification process based on heat pump distillation, characterized in that, The propynyl alcohol purification system using heat pump distillation as described in claim 1 is employed, and the specific steps are as follows: (1) Removal and pretreatment: The mixture containing propynyl alcohol is cooled and then filtered by a centrifuge to remove water-insoluble organic impurities and inorganic salts. The filtrate is then pumped by a transfer pump and successively heated in two heat exchangers before entering the deweighting tower. (2) Removal of impurities and water in the de-weighting tower: The de-weighting tower distillation removes water, high-boiling-point organic impurities and inorganic salts from the filtrate discharged from the centrifuge. A reboiler is installed at the bottom of the tower. After the distillate from the top of the tower is heated by the compressor, the heat is first transferred to the feed of the de-weighting tower through a heat exchanger, and then cooled to 0-30℃ through another heat exchanger. One stream flows back to the top of the tower, and the other stream enters the flash tank. After the de-weighting tower removes impurities and water, a propynyl alcohol aqueous solution with a water content of 30-60wt% is obtained and enters the flash tank. (3) Flash tank impurity removal: The propynyl alcohol aqueous solution discharged from the de-weighting tower enters the flash tank for impurity removal. Low-boiling-point impurities evaporate from the top of the flash tank, and the purified propynyl alcohol aqueous solution enters the azeotropic distillation tower. (4) Dehydration of the azeotropic distillation column: The propynyl alcohol aqueous solution from the flash tank enters from the middle of the azeotropic distillation column, and the azeotropic agent enters from the top of the azeotropic distillation column. After the top distillate is heated by the compressor, it first transfers heat to the azeotropic agent through a heat exchanger, and then cools down to 0-30℃ through another heat exchanger. One stream returns to the top of the column, and the other stream enters the separator. The water is separated from the bottom of the separator, and the azeotropic agent separated from the top is pumped back into the column by a transfer pump. A reboiler is installed at the bottom of the column. After dehydration, a propynyl alcohol aqueous solution with a water content of 1-10wt% is obtained and discharged from the bottom of the column into the purification column. (5) Refining column distillation: The propynyl alcohol aqueous solution from the azeotropic distillation column is further dehydrated in the refining column. The distillate from the top of the column is cooled to 0-30℃ by a heat exchanger and returned to the top of the column, while transferring heat to the feed of the flash tank. A reboiler is installed at the bottom of the column, and high-purity propynyl alcohol with a water content of less than 1wt% is obtained by distillation.

3. The propyne alcohol purification process based on heat pump distillation according to claim 2, characterized in that, In step (1), the mixture containing propynyl alcohol is cooled to -5 to 30°C to allow inorganic salts to precipitate; the centrifuge speed is 1000 to 5000 rpm and the heating temperature is 30 to 100°C.

4. The propyne alcohol purification process based on heat pump distillation according to claim 2, characterized in that, The theoretical number of trays in the deweight removal tower in step (2) is 10-30, the operating pressure is 0-150 kPa, the top temperature is 50-70℃, the bottom temperature is 65-80℃, and the reflux ratio is 1-4; the feed position of the deweight removal tower is at the 5th-15th tray; the outlet pressure of the compressor is 70-100 kPa, and the outlet temperature is 70-100℃.

5. The propyne alcohol purification process based on heat pump distillation according to claim 4, characterized in that, The operating pressure of the deweight removal tower in step (2) is 10-30 kPa.

6. The propyne alcohol purification process based on heat pump distillation according to claim 2, characterized in that, The operating pressure of the flash tank in step (3) is atmospheric pressure, and the operating temperature is 40-80℃.

7. The propyne alcohol purification process based on heat pump distillation according to claim 2, characterized in that, The theoretical number of trays in the azeotropic distillation column described in step (4) is 15-35, the operating pressure is 0-70 kPa, the top temperature is 20-60℃, and the reflux ratio is 1-5; the feed position of the azeotropic distillation column is at the 7th-17th tray.

8. The propyne alcohol purification process based on heat pump distillation according to claim 2, characterized in that, The compressor in step (4) has an outlet pressure of 70-200 kPa and an outlet temperature of 60-90 °C.

9. The propyne alcohol purification process based on heat pump distillation according to claim 2, characterized in that, The azeotropic agent mentioned in step (4) is one of toluene, cyclohexane, and isopropyl ether, and the mass ratio of the azeotropic agent to the water in the feed is 5-20:

1.

10. The propyne alcohol purification process based on heat pump distillation according to claim 2, characterized in that, The theoretical number of trays in the refining tower described in step (5) is 10-40, the operating pressure is 0-70 kPa, the top temperature is 50-100℃, the reflux ratio is 2-5, and the feed position of the refining tower is at the 5th-30th tray.

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