An esterification reaction tower for producing triacetin

Abstract

The invention discloses an esterification reaction tower for the production of triacetin, comprising a tower body, a reboiler, a gas separator, a first condenser, a pervaporation membrane separator, a second condenser, a buffer tank, a reflux channel, a rack mechanism, a mesh drum, and a reduction motor. The invention rapidly and efficiently dehydrates the gas phase azeotrope of water and water-carrying agent generated by the reaction at the top of the tower, and the removed water is concentrated and recovered in the buffer tank, and the recovered water-carrying agent can be sent back to the tower as needed, or discharged, and is flexible to use; the invention can directly retain the activated carbon in the catalyst in the material in the mesh drum, reducing the difficulty of filtering in subsequent processes, and at the same time the mesh drum can reciprocate up and down in the tower and rotate continuously, which, on the one hand, plays a role in stirring the feed liquid, and on the other hand, disperses the activated carbon, which is conducive to the reaction; the feed door of the mesh drum cooperates with the reset spring, the upper pressure head, and the lower pressure head to realize the functions of automatic feeding, cleaning and discharging, and has the advantages of convenient operation and maintenance.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production equipment, and in particular relates to an esterification reaction tower for producing triacetin. Background Art

[0002] When triacetin is synthesized, glycerol and acetic acid can be used as raw materials for esterification reaction. In order to facilitate the reaction, it is usually necessary to add a water-carrying agent and a catalyst, wherein the catalyst can use a concentrated sulfuric acid-activated carbon catalyst, which is prepared by mixing concentrated sulfuric acid and activated carbon in a certain mass ratio and raising them to a certain temperature, cooling and placing them for a certain period of time. After the above raw materials are pre-reacted in the esterification reactor, the materials are sent to the esterification tower to continue the esterification reaction. The azeotrope of the water-carrying agent and water is discharged from the top of the tower in the form of a gas phase. However, the existing equipment has the disadvantage of a long dehydration time when the azeotrope is cooled and dehydrated, which is not conducive to the problem of water-carrying agent recovery. In addition, during the reaction process, the activated carbon is unevenly distributed in the feed liquid, which affects the reaction rate. For this reason, it is very necessary to develop an esterification tower for triacetin production that can solve the above problems. Summary of the invention

[0003] The object of the present invention is to provide an esterification reaction tower for producing triacetin.

[0004] The object of the present invention is achieved in this way, comprising a tower body, a discharge valve is arranged at the bottom of the tower body, a reboiler is arranged at the bottom of the tower body, a gas separator is arranged at the top of the tower body, a plurality of vertical steam guide holes are arranged in the gas separator, a plurality of first condensers are arranged outside the tower body, the upper ends of the steam guide holes are connected to the steam inlet end of the first condenser through pipelines, the first condensers correspond to the steam guide holes one by one, a pervaporation membrane separator, a second condenser, and a buffer tank are arranged in sequence from top to bottom on the outer side of the tower body below the first condenser, the liquid outlet end of the first condenser is connected to the top of the pervaporation membrane separator through pipelines, the water vapor discharge end of the pervaporation membrane separator is connected to the steam inlet end of the second condenser through pipelines, and the liquid outlet end of the second condenser is connected to the buffer tank through pipelines. A tank is connected, a vacuum port is provided on the upper side of the buffer tank, a vertical reflux channel is provided on the outside of the tower body, the upper end of the reflux channel is connected to the retentate discharge end of the pervaporation membrane separator through a pipeline, the lower end of the reflux channel is connected to the reflux port of the tower body through a pipeline, a plurality of slow flow plates are provided in the reflux channel from top to bottom, rack mechanisms are vertically provided on both sides of the lower part of the tower body, a net cylinder is provided between the two rack mechanisms, the rotating shafts at both ends of the net cylinder are respectively connected to the corresponding rack mechanisms, the rotating shafts are respectively sleeved with wheels, a reduction motor is provided on the outside of the tower body, the power output end of the reduction motor is connected to the suspension shaft in the tower body, the wheel is suspended on the suspension shaft through a rope, and a feed door is provided at the feed inlet on the top of the net cylinder.

[0005] The beneficial effects of the present invention are as follows: the present invention can quickly and efficiently dehydrate the gas phase azeotrope of water generated by the reaction and the water-carrying agent at the top of the tower, thus solving the problem of long waiting time for recovery in traditional recovery equipment. The removed water is concentrated and recovered in the buffer tank, and the recovered water-carrying agent can be sent back to the tower as needed, or discharged, which is flexible to use; the slow flow plate in the reflux channel prevents the water-carrying agent from refluxing into the tower body and splashing large droplets, thereby keeping the liquid level stable and facilitating normal stratification in the later stage of the reaction; during feeding, the present invention can directly retain the activated carbon in the catalyst in the material in the mesh cylinder, thus reducing the difficulty of filtering in subsequent processes, and at the same time, the mesh cylinder can reciprocate up and down in the tower and rotate continuously, which can agitate the feed liquid on the one hand and disperse the activated carbon on the other hand, thus facilitating the reaction, increasing the reaction rate and shortening the reaction time; the feeding door of the mesh cylinder cooperates with the reset spring, the upper pressure head and the lower pressure head to realize the functions of automatic feeding, cleaning and discharging, and has the advantages of convenient operation and easy maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a structural schematic diagram of the present invention;

[0007] Figure 2 It is an enlarged structural diagram of the lower part of the tower;

[0008] Figure 3 is a schematic diagram of the side structure of the rack mechanism;

[0009] In the figure: 1-tower body, 2-reboiler, 3-gas distributor, 4-steam guide hole, 5-first condenser, 6-pervaporization membrane separator, 7-second condenser, 8-buffer tank, 9-vacuum port, 10-reflux channel, 11-slow flow plate, 12-rack mechanism, 12a-rack, 12b-gear, 12c-limiting bar, 13-net cylinder, 14-rotating shaft, 15-rotor, 16-reduction motor, 17-suspension shaft, 18-rope, 19-feeding door, 20-upper cross bar, 21-lower cross bar, 22-upper pressure head, 23-lower pressure head, 24-reset spring, 25-feeding pipe, 26-three-way valve. DETAILED DESCRIPTION

[0010] The present invention is further described below in conjunction with the accompanying drawings, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0011] As attached Figure 1~Figure 3The present invention as shown includes a tower body 1, a discharge valve is provided at the bottom of the tower body 1, a reboiler 2 is provided at the bottom of the tower body 1, a gas separator 3 is provided at the top of the tower body 1, a plurality of vertical steam guide holes 4 are provided in the gas separator 3, a plurality of first condensers 5 are provided outside the tower body 1, the upper ends of the steam guide holes 4 are connected to the steam inlet end of the first condenser 5 through pipelines, the first condensers 5 correspond to the steam guide holes 4 one by one, a pervaporation membrane separator 6, a second condenser 7, and a buffer tank 8 are sequentially provided on the outside of the tower body 1 below the first condenser 5 from top to bottom, the liquid outlet end of the first condenser 5 is connected to the top of the pervaporation membrane separator 6 through pipelines, the water vapor discharge end of the pervaporation membrane separator 6 is connected to the steam inlet end of the second condenser 7 through pipelines, the liquid outlet end of the second condenser 7 is connected to the buffer tank through pipelines, a vacuum port 9 is provided on the upper side of the buffer tank, and the outside of the tower body 1 A vertical reflux channel 10 is provided on the side, the upper end of the reflux channel 10 is connected to the retentate discharge end of the pervaporation membrane separator 6 through a pipeline, and the lower end of the reflux channel 10 is connected to the reflux port of the tower body 1 through a pipeline, and a plurality of slow flow plates 11 are provided from top to bottom in the reflux channel 10, rack mechanisms 12 are vertically provided on both sides of the lower part of the tower body 1, a net cylinder 13 is provided between the two rack mechanisms 12, rotating shafts 14 at both ends of the net cylinder 13 are respectively connected to the corresponding rack mechanisms 12, and rotating wheels 15 are respectively sleeved on the rotating shafts 14, a reduction motor 16 is provided on the outside of the tower body 1, and the power output end of the reduction motor 16 is connected to the suspension shaft 17 in the tower body 1, and the rotating wheel 15 is suspended on the suspension shaft 17 by a rope 18, and a feed gate 19 is provided at the top feed port of the net cylinder 13; wherein the net cylinder is a cylinder with a mesh structure on the side wall well known to those skilled in the art.

[0012] Preferably, the rotating wheel 15 is fixed on the rotating shaft 14, and the rotating wheel 15 is provided with a rope groove.

[0013] Preferably, the reboiler 2 is a steam reboiler.

[0014] Preferably, the rack mechanism 12 includes a rack 12a, a gear 12b, and a limit bar 12c. The rack 12a and the limit bar 12c are parallel and opposite to each other, the tooth surface of the rack 12a faces the limit bar 12c, the gear 12b is arranged between the rack 12a and the limit bar 12c, and the gear 12b is meshed with the rack 12a, and the gear 12b is fixed to the end of the rotating shaft 14.

[0015] Preferably, an upper cross bar 20 is provided at the lower part of the tower body 1, a lower cross bar 21 is provided at the bottom of the tower body 1, an upper pressure head 22 is provided at the bottom of the upper cross bar 20, a lower pressure head 23 is provided at the top of the lower cross bar 21, and the upper pressure head 22 and the lower pressure head 23 are arranged opposite to each other, the rack mechanism 12 is located between the upper cross bar 20 and the lower cross bar 21, the feed gate 19 is located in the mesh cylinder 13, and a return spring 24 is provided in the mesh cylinder 13, and the top of the return spring 24 is connected to the inner side of the feed gate 19.

[0016] Preferably, the feed pipe 25 is located between the suspension shaft 17 and the mesh cylinder 13 , and the feed opening at the end of the feed pipe 25 corresponds to the feed gate 19 .

[0017] Preferably, the mesh cylinder 13 is a spindle-shaped structure.

[0018] Preferably, a counterweight block is provided on the net cylinder 13.

[0019] Preferably, the slow flow plates 11 are staggered up and down so that the liquid flowing from top to bottom in the reflux channel 10 forms a zigzag liquid flow on the slow flow plates 11 .

[0020] Preferably, the vacuum port 9 is connected to a vacuum pump through a pipeline.

[0021] Preferably, the height of the tower body 1 is 20 meters.

[0022] Preferably, the first condenser 5 and the second condenser 7 are both water condensers.

[0023] Preferably, the number of the steam-conducting holes 4 is at least four.

[0024] Preferably, a drain valve is provided at the bottom of the buffer tank 8.

[0025] The working principle and working process of the present invention are as follows: the semi-finished product material flows into the mesh cylinder 13 from the feeding port at the end of the feeding pipe 25 through the feeding port at the top of the mesh cylinder 13; the mesh structure of the mesh cylinder 13 blocks the activated carbon in the catalyst in the material in the mesh cylinder 13, and the remaining material falls to the bottom of the tower body 1 through the mesh structure; the temperature in the tower body 1 is controlled by the reboiler 2, and the unreacted material continues to react in the tower body 1. During this period, the reduction motor 16 is started, and the suspension shaft 17 slowly lowers the rope 18 during the rotation process, that is, the mesh cylinder 13 begins to descend, and the feeding door 19 of the mesh cylinder 13 is separated from the upper pressure head 22. Under the action of the reset spring 24, the feeding door 19 closes the feeding port of the mesh cylinder 13. The net cylinder 13 is pressed against and sealed to prevent the activated carbon in the net cylinder 13 from leaking out; during the descent of the net cylinder 13, the gear 12b in the rack mechanism 12 and the rack 12a are meshed, and the gear 12b continuously rotates and moves downward, so that the net cylinder 13 continuously rotates, and the net cylinder 13 rotates and descends in the liquid of the tower body 1, which, on the one hand, stirs the liquid, and on the other hand, the activated carbon in the net cylinder 13 continuously rotates, so that the activated carbon is dispersed, which is beneficial to the reaction; when the net cylinder 13 descends to a certain height, the reduction motor 16 rotates in the opposite direction, so that the net cylinder 13 continuously rises during the reverse rotation, and when it reaches a certain height, it descends and continuously repeats the rising and falling actions; the water generated in the reaction process is azeotropic with the water-carrying agent Gas is formed, and the gas rises and is divided through the steam guide holes 4 of the gas distributor plate 3 and sent to different first condensers, thereby reducing the processing pressure of a single first condenser and ensuring the condensation effect. The gas enters the first condenser 5 and is condensed into liquid, and the liquid enters the pervaporation membrane separator 6. Since the downstream side of the pervaporation membrane in the pervaporation membrane separator 6 is in a reduced pressure state under the action of the vacuum pump, the water in the liquid forms water vapor after passing through the pervaporation membrane, and the water vapor is condensed into water through the second condenser 7 and flows into the buffer tank 8, while the water-carrying agent retained on the pervaporation membrane flows into the reflux channel 10 through the retentate discharge end, and the slow flow plate in the reflux channel 10 plays the role of slowing down the flow of the water-carrying agent, and the water-carrying agent From the lower end of the reflux channel 10, it refluxes into the tower body 1 through the reflux port of the tower body 1 to prevent the water-carrying agent from reflux into the tower body 1 and splashing large droplets, keep the liquid level stable, and facilitate normal stratification in the later stage of the reaction; when it is necessary to discharge the recovered water-carrying agent, the passage from the three-way valve 26 to the reflux port of the tower body 1 can be closed through the three-way valve 26, and the passage from the three-way valve 26 to the external discharge pipe can be opened, so that the water-carrying agent can be discharged from the external discharge pipe; when it is necessary to clear the activated carbon in the mesh cylinder 13, the mesh cylinder 13 is first lowered to the maximum position by the reduction motor 16, and the feed door 19 of the mesh cylinder 13 is resisted and pushed open by the down-pressure head 23, with the feed port facing downward, and then the mesh cylinder 13 is flushed through the feed pipe 25, and the activated carbon is discharged from the feed port.

Claims

1. An esterification reaction tower for producing triacetin, comprising a tower body (1), a discharge valve being provided at the bottom of the tower body (1), characterized in that The tower body (1) is provided with a reboiler (2) at the bottom, a gas separator (3) is provided at the top of the tower body (1), a plurality of vertical steam guide holes (4) are provided in the gas separator (3), a plurality of first condensers (5) are provided outside the tower body (1), the upper ends of the steam guide holes (4) are connected to the steam inlet ends of the first condensers (5) through pipelines, the first condensers (5) correspond to the steam guide holes (4) one by one, a pervaporation membrane separator (6), a second condenser (7), and a buffer tank (8) are provided on the outside of the tower body (1) below the first condensers (5) in order from top to bottom, the liquid outlet ends of the first condensers (5) are connected to the tops of the pervaporation membrane separators (6) through pipelines, the water vapor discharge ends of the pervaporation membrane separators (6) are connected to the steam inlet ends of the second condensers (7) through pipelines, the liquid outlet ends of the second condensers (7) are connected to the buffer tank through pipelines, the upper side of the buffer tank is provided with a vacuum port (9), the outside of the tower body (1) is provided with a vacuum port (9), and the inside of the tower body (1) is provided with a vacuum port (9). A vertical reflux channel (10) is provided on the side, the upper end of the reflux channel (10) is connected to the retentate discharge end of the pervaporation membrane separator (6) through a pipeline, and the lower end of the reflux channel (10) is connected to the reflux port of the tower body (1) through a pipeline. A plurality of slow flow plates (11) are provided from top to bottom in the reflux channel (10), and rack mechanisms (12) are vertically provided on both sides of the lower part of the tower body (1), and a net cylinder (13) is provided between the two rack mechanisms (12). (13) The rotating shafts (14) at both ends are respectively connected to the corresponding rack mechanisms (12), and the rotating shafts (14) are respectively sleeved with rotating wheels (15). A reduction motor (16) is provided on the outside of the tower body (1), and the power output end of the reduction motor (16) is connected to the suspension shaft (17) in the tower body (1). The rotating wheel (15) is suspended on the suspension shaft (17) through a rope (18), and a feeding door (19) is provided at the feeding port on the top of the net cylinder (13); The feed pipe (25) is located between the suspension shaft (17) and the net cylinder (13), and the feed opening at the end of the feed pipe (25) corresponds to the feed gate (19); The slow flow plate (11) is staggered between the upper and lower parts, so that the liquid flowing from top to bottom in the reflux channel (10) forms a zigzag liquid flow on the slow flow plate (11).

2. The esterification reaction tower for triacetin production according to claim 1, characterized in that The rack mechanism (12) comprises a rack (12a), a gear (12b), and a limit bar (12c); the rack (12a) and the limit bar (12c) are parallel and arranged opposite to each other; the tooth surface of the rack (12a) faces the limit bar (12c); the gear (12b) is arranged between the rack (12a) and the limit bar (12c); the gear (12b) is meshed with the rack (12a); and the gear (12b) is fixedly connected to the end of the rotating shaft (14).

3. The esterification reaction tower for triacetin production according to claim 1, characterized in that An upper cross bar (20) is provided at the lower part of the tower body (1), a lower cross bar (21) is provided at the bottom of the tower body (1), an upper pressure head (22) is provided at the bottom of the upper cross bar (20), a lower pressure head (23) is provided at the top of the lower cross bar (21), and the upper pressure head (22) and the lower pressure head (23) are arranged opposite to each other, the rack mechanism (12) is located between the upper cross bar (20) and the lower cross bar (21), the feed gate (19) is located in the net cylinder (13), a return spring (24) is provided in the net cylinder (13), and the top of the return spring (24) is connected to the inner side of the feed gate (19).

4. The esterification reaction tower for triacetin production according to claim 1 or 3, characterized in that The net cylinder (13) is a spindle-shaped structure.

5. The esterification reaction tower for triacetin production according to claim 1, characterized in that The net cylinder (13) is provided with a counterweight block.

6. The esterification reaction tower for producing triacetin according to claim 1, characterized in that The vacuum port (9) is connected to a vacuum pump via a pipeline.

7. The esterification reaction tower for producing triacetin according to claim 1, characterized in that The height of the tower body (1) is 20 meters.

8. The esterification reaction tower for producing triacetin according to claim 1, characterized in that A three-way valve (26) is provided on the pipeline between the lower end of the reflux channel (10) and the reflux port of the tower body (1), and the three-way valve (26) is connected to an external discharge pipe.

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