Rectification extraction device for improving quality of propylene glycol

Abstract

The utility model discloses a rectification extraction device capable of improving the quality of propylene glycol, which belongs to the technical field of rectification and is characterized in that propylene glycol steam generated at high temperature is introduced into a preheating tank and is conveyed upwards along a spiral preheating structure to transfer heat to a mixed solution containing propylene glycol, which is conveyed downwards by the preheating structure, so that the quality of propylene glycol is improved. According to the multi-stage rectification device, the temperature of mixed liquid primarily entering the first rectification tower is effectively increased, propylene glycol steam after being cooled is guided into the second rectification tower to be subjected to secondary rectification after being cooled by the condenser, and the rectification effect is effectively improved through multi-stage rectification, in addition, a stirring barrel matched with a stirring shaft is additionally arranged in the first rectification tower, and the rectification efficiency is improved. Waste liquid in the second rectifying tower is guided into the stirring barrel through the second discharging pipe and mixed with preheated mixed liquid, on one hand, the waste liquid with waste heat is used for conducting secondary preheating on the mixed liquid, on the other hand, the stirring structure is additionally arranged, the heating uniformity of the mixed liquid is improved, and the heating effect is enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of distillation, and more specifically to a distillation extraction device for improving the quality of propylene glycol. Background Art

[0002] Propylene glycol is also known as 1,2-propylene glycol. It is a colorless, odorless, viscous liquid that is soluble in water and most organic solvents. It is widely used in many different fields, including cosmetics, food, medicine, plastics and refrigerants.

[0003] The propylene glycol distillation system is a device used to separate and purify propylene glycol. Based on the difference in boiling points of different components, the mixture is heated by an external reboiler or a built-in heating coil. The high-temperature steam is discharged from the top of the tower and cooled to turn it into a liquid state. This liquid is pure propylene glycol. The solution inside the existing distillation tower takes a lot of time to preheat, and the heating speed is slow. In the cooling process of the high-temperature steam, it is usually cooled directly, which fails to fully utilize the thermal energy of the gaseous propylene glycol, resulting in energy waste.

[0004] To this end, we propose a distillation extraction device to improve the quality of propylene glycol to address the above problems, using waste heat to preheat the mixture when it is introduced into the distillation tower. Utility Model Content

[0005] The utility model aims to solve the existing problems and provides a distillation extraction device for improving the quality of propylene glycol compared with the existing technology. The propylene glycol vapor generated by high temperature is introduced into a preheating tank, and the propylene glycol vapor is transmitted upward along the spiral preheating structure to transfer heat to the mixed liquid containing propylene glycol transmitted downward by the preheating structure, thereby effectively improving the temperature of the mixed liquid when it first enters the first distillation tower. In addition, a stirring drum matched with a stirring shaft is added in the first distillation tower, and the waste liquid in the second distillation tower is introduced into the stirring drum by a second discharge pipe and mixed with the preheated mixed liquid. On the one hand, the waste liquid with residual heat is used to preheat the mixed liquid for a second time, and on the other hand, a stirring structure is added, which is beneficial to improving the heating uniformity of the mixed liquid and enhancing the heating effect.

[0006] The purpose of the utility model can be achieved through the following technical solutions: a distillation extraction device for improving the quality of propylene glycol, comprising a first distillation tower and a second distillation tower, wherein a preheating tank is provided on one side of the upper end of the first distillation tower, a reflux pipe is installed inside the preheating tank, a preheating structure is sleeved on the outside of the reflux pipe, a first feed pipe connected to the preheating structure is fixedly connected to the top of the preheating tank, the bottom end of the preheating structure passes through the bottom of the preheating tank and is connected to the inside of the first distillation tower through the second feed pipe, a first exhaust pipe connected to the inside of the bottom of the preheating tank is fixedly connected to the top of the first distillation tower, a reflux port is provided on the top wall of the reflux pipe, a discharge pipe is fixedly connected to the bottom end of the reflux pipe, the other end of the discharge pipe is connected to the inside of the second distillation tower, a second exhaust pipe is fixedly connected to the top of the second distillation tower, a second discharge pipe and a first discharge pipe are respectively provided at the bottom of the second distillation tower and the first distillation tower, and the other end of the second discharge pipe passes through the inside of the first distillation tower;

[0007] A stirring drum is embedded in the first distillation tower, a driving motor is fixedly installed on the top of the first distillation tower, and a driving shaft of the driving motor is connected to a stirring shaft extending to the stirring drum.

[0008] Furthermore, the preheating structure includes a spiral sheet fixedly mounted on the outer end wall of the reflux pipe, a spiral tube matched with the spiral sheet is wound around the spiral sheet, the spiral sheet and the outer end wall of the spiral tube are fitted with the inner end wall of the preheating tank, and the upper and lower ends of the spiral tube are respectively connected to the first feed pipe and the second feed pipe.

[0009] Furthermore, the spiral sheet and the spiral tube are spiral structures with matching structures, and an exhaust space which is also arranged in a spiral upward shape is reserved between the spiral sheet and the spiral tube.

[0010] Furthermore, the reflux pipe, spiral sheets, and spiral tubes are all made of heat-conducting materials. The upper end of the first exhaust pipe extends to the bottom end of the exhaust space, and the reflux port is connected to the top of the exhaust space. The mixed liquid containing propylene glycol is introduced into the spiral tube through the first feed pipe and transmitted downward through the spiral tube. During the transmission process, the steam generated by the high temperature inside the first distillation tower is introduced into the preheating tank through the first exhaust pipe, and transmitted upward along the exhaust space of the spiral structure formed by the spiral sheets and the spiral tube, so as to heat the mixed liquid transmitted downward by the spiral tube.

[0011] Furthermore, the mixing drum is a conical structure that is wide at the top and narrow at the bottom. The outer diameter of the mixing drum is smaller than the inner diameter of the first distillation tower. The outer end wall of the mixing drum is fixedly mounted with a plurality of heating blocks that are arranged in close contact with the inner wall of the first distillation tower.

[0012] Furthermore, the lower end of the stirring shaft passes through the stirring drum and extends to the bottom of the first distillation tower. The stirring shaft is located inside the stirring drum and on the end wall at the bottom of the first distillation tower, stirring rods are distributed. The lower port of the second feed pipe and the upper port of the second discharge pipe are respectively located on both sides of the upper end of the stirring drum. The initially preheated mixed liquid is introduced into the stirring drum through the second feed pipe, and the waste liquid with residual heat in the second distillation tower is also introduced into the stirring drum through the second discharge pipe. The two are mixed under the rotation of the stirring shaft and the stirring rod. On the one hand, the mixed liquid is preheated for the second time by using the waste liquid with residual heat. On the other hand, the addition of a stirring structure is beneficial to improving the uniformity of heating of the mixed liquid and enhancing the heating effect.

[0013] Compared with the prior art, the advantages of the present invention are:

[0014] (1) This scheme is to pass the propylene glycol vapor generated at high temperature into the preheating tank, and the propylene glycol vapor is transmitted upward along the spiral preheating structure to transfer heat to the mixed liquid containing propylene glycol transmitted downward by the preheating structure, thereby effectively increasing the temperature of the mixed liquid when it first enters the first distillation tower. The cooled propylene glycol vapor is cooled by the condenser and then introduced into the second distillation tower for secondary distillation. Through multi-stage distillation, the distillation effect is effectively improved. In addition, a stirring drum with a stirring shaft is added to the first distillation tower, and the waste liquid in the second distillation tower is introduced into the stirring drum through the second discharge pipe and mixed with the preheated mixed liquid. On the one hand, the waste liquid with residual heat is used to preheat the mixed liquid for the second time. On the other hand, the addition of a stirring structure is conducive to improving the uniformity of heating of the mixed liquid and enhancing the heating effect.

[0015] (2) The preheating structure in this scheme is composed of spiral sheets and spiral tubes that are arranged in a mutually coordinated manner. The reflux pipe, spiral sheets and spiral tubes are all made of heat-conducting materials. The mixed liquid containing propylene glycol is introduced into the spiral tube through the first feed pipe and transmitted downward through the spiral tube. During the transmission process, the steam generated by the high temperature inside the first distillation tower is introduced into the preheating tank through the first exhaust pipe, and is transmitted upward along the exhaust space of the spiral structure formed by the spiral sheets and the spiral tube. The mixed liquid transmitted downward by the spiral tube is heated and arranged into a spiral structure to increase the heating area and time of the mixed liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the external structure of the utility model;

[0017] Figure 2 The utility model is a cross-sectional view Figure 1 ;

[0018] Figure 3 The utility model is a cross-sectional view Figure 2 ;

[0019] Figure 4This is a schematic diagram of the structure of the preheating tank of the utility model when it is disassembled. Figure 1 ;

[0020] Figure 5 This is a schematic diagram of the structure of the preheating tank of the utility model when it is disassembled. Figure 2 ;

[0021] Figure 6 It is a schematic structural diagram of the spiral sheet and the spiral tube of the utility model when they are separated.

[0022] Description of the numbers in the figure:

[0023] 1. First distillation tower; 2. Second distillation tower; 3. Preheating tank; 4. Second feed pipe; 5. Reflux pipe; 501. Reflux port; 502. Discharge pipe; 6. Spiral sheet; 7. Spiral pipe; 8. First feed pipe; 9. First exhaust pipe; 10. Third feed pipe; 11. Condenser; 12. Second discharge pipe; 13. First discharge pipe; 14. Stirring drum; 15. Stirring shaft; 151. Stirring rod; 16. Drive motor; 17. Second exhaust pipe. DETAILED DESCRIPTION

[0024] The following will combine the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. All other embodiments obtained by ordinary technicians in this field without creative work based on the embodiments in the utility model belong to the scope of protection of the utility model.

[0025] Embodiment 1:

[0026] The utility model discloses a distillation extraction device for improving the quality of propylene glycol. Figure 1 , including a first distillation tower 1 and a second distillation tower 2, a preheating tank 3 is provided on one side of the upper end of the first distillation tower 1, a reflux pipe 5 is fixedly connected to the upper and lower end walls of the preheating tank 3, a preheating structure is sleeved on the outside of the reflux pipe 5, a first feed pipe 8 connected to the preheating structure is fixedly connected to the top of the preheating tank 3, the bottom end of the preheating structure passes through the bottom of the preheating tank 3 and is connected to the inside of the first distillation tower 1 through the second feed pipe 4, a first exhaust pipe 9 is fixedly connected to the top of the first distillation tower 1, and the other end of the first exhaust pipe 9 passes through the inside of the bottom of the preheating tank 3;

[0027] See also Figure 2-Figure 6The preheating structure includes a spiral sheet 6 fixedly sleeved on the outer end wall of the reflux pipe 5, a spiral tube 7 matched with the spiral sheet 6 is wound around the spiral sheet 6, the outer end walls of the spiral sheet 6 and the spiral tube 7 are fitted with the inner end wall of the preheating tank 3, the upper and lower ends of the spiral tube 7 are respectively connected with the first feed pipe 8 and the second feed pipe 4, the spiral sheet 6 and the spiral tube 7 are spiral structures matched with each other, and an exhaust space which is also spirally arranged upward is reserved between the spiral sheet 6 and the spiral tube 7.

[0028] The top wall of the reflux pipe 5 is provided with a reflux port 501 connected to the interior thereof, the bottom end of the reflux pipe 5 is fixedly connected with a discharge pipe 502, the other end of the discharge pipe 502 is connected with a third feed pipe 10 connected to the interior of the second distillation tower 2 through a condenser 11, the reflux pipe 5, the spiral sheet 6, and the spiral tube 7 are all made of heat-conducting materials, the upper end of the first exhaust pipe 9 extends to the bottom end of the exhaust space, the reflux port 501 is connected to the top of the exhaust space, the mixed liquid containing propylene glycol is introduced into the spiral tube 7 through the first feed pipe 8, and is transmitted downward through the spiral tube 7. During the transmission process, the steam generated by the high temperature inside the first distillation tower 1 is introduced into the preheating tank 3 through the first exhaust pipe 9, and is transmitted upward along the exhaust space of the spiral structure formed by the spiral sheet 6 and the spiral tube 7, the mixed liquid transmitted downward by the spiral tube 7 is heated, and the temperature of the mixed liquid is increased when it first enters the first distillation tower 1;

[0029] After the steam reaches the top of the exhaust space, it is transmitted downward by the reflux pipe 5 and introduced into the condenser 11 through the discharge pipe 502. The liquid after cooling and condensation is introduced into the second distillation tower 2 through the third feed pipe 10 for secondary distillation. The top of the second distillation tower 2 is fixedly connected with a second exhaust pipe 17. The propylene glycol gas produced by the secondary distillation is discharged from the second exhaust pipe 17 and is also collected after condensation and cooling by the condenser 11. The second distillation tower 2 and the first distillation tower 1 are respectively provided with a second discharge pipe 12 and a first discharge pipe 13 at the bottom ends. The other end of the second discharge pipe 12 passes through the interior of the first distillation tower 1. The waste liquid in the second distillation tower 2 is discharged from the second discharge pipe 12 into the interior of the first distillation tower 1 for distillation again. After multiple distillations, the waste liquid in the first distillation tower 1 is discharged through the first discharge pipe 13.

[0030] Embodiment 2:

[0031] See also Figure 2 , Figure 3 A stirring drum 14 corresponding to the inlet positions of the second feed pipe 4 and the second discharge pipe 12 is embedded in the first distillation tower 1, and a driving motor 16 is fixedly installed on the top of the first distillation tower 1. The driving shaft of the driving motor 16 passes through the first distillation tower 1 and is fixedly connected to a stirring shaft 15 extending to the stirring drum 14.

[0032] Specifically, the stirring drum 14 is a conical structure that is wide at the top and narrow at the bottom. The outer diameter of the stirring drum 14 is smaller than the inner diameter of the first distillation tower 1. A plurality of heating blocks that are arranged in contact with the inner wall of the first distillation tower 1 are fixedly installed on the outer end wall of the stirring drum 14. The lower end of the stirring shaft 15 passes through the stirring drum 14 and extends to the bottom of the first distillation tower 1. The stirring shaft 15 is located inside the stirring drum 14 and has stirring rods 151 distributed on the end wall at the bottom of the first distillation tower 1. The lower port of the second feed pipe 4 and the upper port of the second discharge pipe 12 are respectively located on both sides of the upper end of the stirring drum 14. The preheated mixed liquid is introduced into the stirring drum 14 through the second feed pipe 4, and the waste liquid with residual heat in the second distillation tower 2 is also introduced into the stirring drum 14 through the second discharge pipe 12. The two are mixed under the rotation of the stirring shaft 15 and the stirring rod 151. On the one hand, the waste liquid with residual heat is used to preheat the mixed liquid for the second time. On the other hand, the stirring structure is added, which is beneficial to improving the uniformity of heating of the mixed liquid and enhancing the heating effect.

[0033] The working process and principle of the utility model are as follows:

[0034] First, the mixed liquid containing propylene glycol is introduced into the spiral tube 7 through the first feed pipe 8 and transmitted downward through the spiral tube 7. During the transmission process, the propylene glycol vapor generated by the high temperature inside the first distillation tower 1 is introduced into the preheating tank 3 through the first exhaust pipe 9, and is transmitted upward along the exhaust space of the spiral structure formed by the spiral sheet 6 and the spiral tube 7. The mixed liquid transmitted downward by the spiral tube 7 is heated to increase the temperature of the mixed liquid when it first enters the first distillation tower 1. After the steam reaches the top of the exhaust space, it is introduced into the reflux pipe 5 through the reflux port 501, and is introduced into the condenser 11 along the reflux pipe 5 and the discharge pipe 502. The liquid after cooling and condensation is introduced into the second distillation tower 2 through the third feed pipe 10 for secondary distillation. The propylene glycol gas generated by the secondary distillation is discharged from the second exhaust pipe 17 and is also condensed and cooled by the condenser 11 and collected;

[0035] The waste liquid in the second distillation tower 2 is discharged from the second discharge pipe 12 into the stirring drum 14 in the first distillation tower 1 to mix with the preheated mixed liquid. At this time, the drive motor 16 is started, and the drive motor 16 drives the stirring shaft 15 to rotate. The multiple groups of stirring rods 151 stir the mixed liquid in the stirring drum 14 and at the bottom of the first distillation tower 1 respectively to improve the uniformity of heating of the mixed liquid. After multiple distillations, the waste liquid in the first distillation tower 1 is discharged through the first discharge pipe 13.

[0036] The above are only preferred specific implementation methods of the utility model, but the protection scope of the utility model is not limited to them. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the utility model according to the technical solution and improved ideas of the utility model, which should be included in the protection scope of the utility model.

Claims

1. A distillation extraction device for improving the quality of propylene glycol, comprising a first distillation tower (1) and a second distillation tower (2), wherein a preheating tank (3) is provided on one side of the upper end of the first distillation tower (1), a reflux pipe (5) is installed inside the preheating tank (3), a preheating structure is sleeved on the outside of the reflux pipe (5), a first feed pipe (8) connected to the preheating structure is fixedly connected to the top of the preheating tank (3), the bottom end of the preheating structure passes through the bottom of the preheating tank (3) and is connected to the inside of the first distillation tower (1) through a second feed pipe (4), characterized in that: The top of the first distillation tower (1) is fixedly connected to a first exhaust pipe (9) which is connected to the interior of the lower part of the preheating tank (3); the top wall of the reflux pipe (5) is provided with a reflux port (501); the bottom end of the reflux pipe (5) is fixedly connected to a discharge pipe (502); the other end of the discharge pipe (502) is connected to the interior of the second distillation tower (2); the top of the second distillation tower (2) is fixedly connected to a second exhaust pipe (17); the bottom ends of the second distillation tower (2) and the first distillation tower (1) are respectively provided with a second discharge pipe (12) and a first discharge pipe (13); the other end of the second discharge pipe (12) passes through the interior of the first distillation tower (1); A stirring drum (14) is embedded in the first distillation tower (1), a driving motor (16) is fixedly installed on the top of the first distillation tower (1), and a driving shaft of the driving motor (16) is connected to a stirring shaft (15) extending to the stirring drum (14).

2. A distillation extraction device for improving the quality of propylene glycol according to claim 1, characterized in that: The preheating structure comprises a spiral sheet (6) fixedly sleeved on the outer end wall of the return pipe (5), a spiral tube (7) matched with the spiral sheet (6) being wound around the spiral sheet (6), the outer end walls of the spiral sheet (6) and the spiral tube (7) being arranged in close contact with the inner end wall of the preheating tank (3), and the upper and lower ends of the spiral tube (7) being respectively connected with the first feed pipe (8) and the second feed pipe (4).

3. A distillation extraction device for improving the quality of propylene glycol according to claim 2, characterized in that: The spiral sheet (6) and the spiral tube (7) are spiral structures with matching structures, and an exhaust space which is also arranged in a spiral upward direction is reserved between the spiral sheet (6) and the spiral tube (7).

4. A distillation extraction device for improving the quality of propylene glycol according to claim 3, characterized in that: The reflux pipe (5), spiral sheet (6) and spiral pipe (7) are all made of heat-conducting material; the upper end of the first exhaust pipe (9) extends to the bottom end of the exhaust space; and the reflux port (501) is connected to the top end of the exhaust space.

5. A distillation extraction device for improving the quality of propylene glycol according to claim 1, characterized in that: The stirring drum (14) is in the shape of a cone that is wider at the top and narrower at the bottom. The outer diameter of the stirring drum (14) is smaller than the inner diameter of the first distillation tower (1). A plurality of heating blocks that are arranged in close contact with the inner wall of the first distillation tower (1) are fixedly mounted on the outer end wall of the stirring drum (14).

6. A distillation extraction device for improving the quality of propylene glycol according to claim 5, characterized in that: The lower end of the stirring shaft (15) passes through the stirring drum (14) and extends to the bottom of the first distillation tower (1). The stirring shaft (15) is located inside the stirring drum (14) and a stirring rod (151) is distributed on the end wall at the bottom of the first distillation tower (1). The lower end of the second feed pipe (4) and the upper end of the second discharge pipe (12) are respectively located on both sides of the upper end of the stirring drum (14).

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