A kind of n-butyl acetate purification equipment

Abstract

The invention discloses a n-butyl acetate purification device, comprising an n-butyl acetate purification device, a temperature control device and a temperature control system; the n-butyl acetate purification device comprises a distillation tower and a condenser, wherein a plurality of tower plates are arranged in the distillation tower; the temperature control device comprises a cold liquid tank, a temperature control tank arranged along the height direction of the distillation tower and a cooling component, wherein the plurality of tower plates extend into the temperature control tank, a temperature control heater for heating the tower plates is arranged at a portion of the tower plates located in the temperature control tank, the cooling component comprises an air shower cooling pipe and a second shut-off valve arranged in the temperature control tank, the air shower cooling pipe is provided with a plurality of spray valves opposite to the temperature control heater, the second shut-off valve is arranged between the air shower cooling pipe and the cold liquid tank for connecting or shutting off the two, a heat exchange pipe is connected to the cold liquid tank, cold liquid can be stored in the cold liquid tank, the temperature control system is configured with a temperature monitoring module and a cooling control module, and the cooling control module controls the cooling component according to a first temperature sensing subunit and a second temperature sensing subunit.

Description

Technical Field

[0001] The invention relates to the field of n-butyl acetate purification, in particular to n-butyl acetate purification equipment. Background Art

[0002] In the purification process of n-butyl acetate, high-purity n-butyl acetate is generally obtained by multiple distillations. n-butyl acetate is purified by a distillation tower, and the steam is condensed by a condenser. n-butyl acetate is a colorless, flammable liquid with a relative density of 0.8825, a freezing point of -77.9°C, a boiling point of 126°C, a flash point of 33°C, and an ignition temperature of n-butyl acetate vapor of 370°C. At present, the distillation towers on the market are generally explosion-proof by temperature control, pressure control, and flow control, and it is very easy to set up explosion-proof covers. Application No. CN201110089476.3 involves a method for preventing the explosion of a nitration product distillation tower by adding a stabilizer to achieve an explosion-proof effect. When such flammable liquids as n-butyl acetate are distilled, the distillation tower converts n-butyl acetate from liquid to vapor, and collects the boiling point of 120-130 ℃ fraction to obtain high-purity n-butyl acetate. n-Butyl acetate is flammable and is very likely to cause combustion and explosion when encountering open flames and high thermal energy. The distillation tower of the prior art can avoid encountering open flames, but when the combustion temperature of n-butyl acetate is reached due to reasons such as failure of the heating module of the distillation tower, n-butyl acetate is very likely to cause combustion and explosion. Summary of the invention

[0003] The invention aims at the defect that n-butyl acetate as a flammable liquid in the prior art is prone to combustion and explosion during distillation, and provides n-butyl acetate purification equipment.

[0004] In order to solve the above technical problems, the present invention is solved by the following technical solutions: a n-butyl acetate purification device, comprising a n-butyl acetate purification device, a temperature control device and a temperature control system;

[0005] The n-butyl acetate purification device comprises a distillation tower and a condenser, wherein a plurality of tower plates are arranged in the distillation tower, the condenser is provided with a heat exchange pipe, the temperature control device comprises a cold liquid tank, a temperature control tank arranged along the height direction of the distillation tower and a cooling component, a plurality of the tower plates extend into the temperature control tank, a temperature control heater for heating the tower plates is arranged at the part of the tower plates located in the temperature control tank, the cooling component comprises an air shower cooling pipe and a second shut-off valve arranged in the temperature control tank, the air shower cooling pipe is provided with a plurality of spray valves opposite to the temperature control heater, the second shut-off valve is arranged between the air shower cooling pipe and the cold liquid tank for connecting or shutting off the two, the heat exchange pipe is connected to the cold liquid tank, and cold liquid can be stored in the cold liquid tank,

[0006] The temperature control system is equipped with a temperature monitoring module and a temperature reduction control module. The temperature monitoring module includes a plurality of first temperature sensing subunits and a plurality of second temperature sensing subunits. The plurality of first temperature sensing subunits are arranged at intervals along the height direction of the inner wall of the distillation tower. The second temperature sensing subunits are used to correspond one by one to the temperature control heaters.

[0007] The temperature reduction control module controls the temperature reduction component according to the first temperature sensing sub-unit and the second temperature sensing sub-unit.

[0008] By adopting the above technical scheme, when it is detected that the temperature of the temperature control heating module of the distillation tower exceeds the preset range, the temperature control heating module can be cooled in real time by the cooling component. The cooling method is that the temperature control heating module and its layer tower plate can be cooled by the spray pipe. The layer tower plate is located in the distillation tower and can be used as a carrier for heat conduction. While cooling the layer tower plate, the heat transfer through the layer tower plate can simultaneously achieve the effect of cooling the distillation tower.

[0009] The present invention is further configured as follows: the distillation tower is provided with a ventilation control module, the ventilation control module includes an exhaust subunit and an air intake subunit, the exhaust subunit and the air intake subunit are both arranged in the distillation tower, the exhaust subunit is used to discharge the gas in the distillation tower, the air intake subunit is connected to the heat exchange pipe, and the gas passing through the heat exchange pipe enters the distillation tower through the air intake subunit.

[0010] By adopting the above technical solution, the heat exchange tube is located in the condenser. After the cold liquid enters the heat exchange tube, the steam can be cooled by the cold liquid, which has the effect of accelerating condensation. At the same time, part of the liquid nitrogen in the heat exchange tube is changed from liquid to gas due to heat absorption. The gaseous nitrogen or carbon dioxide enters the distillation tower and can discharge the oxygen in the distillation tower. After ventilation for a period of time, the distillation tower can be completely filled with nitrogen. After ventilation, the distillation tower discharges most of the oxygen, which greatly reduces the possibility of combustion of n-butyl acetate.

[0011] The present invention is further configured as follows: the air intake subunit includes an expansion airbag and a third control valve, the heat exchange tube is connected to the expansion airbag, the third control valve is arranged between the expansion airbag and the distillation tower, and the third control valve is used to connect or cut off the expansion airbag and the distillation tower.

[0012] By adopting the above technical solution, the amount of nitrogen or carbon dioxide entering the distillation tower can be controlled by the third control valve, and the expansion airbag can be used to perform intermediate storage of the gasified nitrogen or carbon dioxide. The expansion airbag is elastic and can also facilitate the entry of the gas into the distillation tower.

[0013] The present invention is further configured as follows: the third control valve adopts a four-way reversing valve, the four-way reversing valve is provided with four valve ports, and the four valve ports are respectively connected to the expansion airbag, the distillation tower, the air shower cooling pipe and the pressure relief tail gas pipe.

[0014] By adopting the above technical solution and a reversing valve, the gas in the expansion airbag can be controlled to enter the distillation tower or the air shower cooling pipe, or to avoid excessive air pressure in the expansion airbag, the gas in the expansion airbag can be discharged through the pressure relief tail pipe.

[0015] The present invention is further configured as follows: the cold liquid tank is arranged above the temperature control tank, and the cooling component also includes a first shut-off valve, which is arranged between the cold liquid tank and the temperature control tank to connect or cut off the two.

[0016] By adopting the above technical solution, the passage between the cold liquid cabin and the temperature control cabin can be directly opened through the first shut-off valve, so that cold liquid can be directly poured into the temperature control cabin for rapid cooling.

[0017] The present invention is further configured as follows: the cooling control module is configured with a cooling strategy table, and the cooling strategy table is configured with a small cooling strategy, a medium cooling strategy and a large cooling strategy according to different degrees of exceeding the preset temperature. The small cooling strategy uses an expansion air bag connected to an air shower cooling pipe for cooling, the medium cooling strategy uses an expansion air bag connected to an air shower cooling pipe and opens the second shut-off valve for cooling, and the large cooling strategy uses opening the first shut-off valve for cooling.

[0018] By adopting the above technical solution, a small cooling strategy, a medium cooling strategy or a large cooling strategy can be selected according to the first temperature sensing subunit and the second temperature sensing subunit, thereby avoiding heat waste.

[0019] The present invention is further configured such that: the cooling liquid is liquid nitrogen or liquid carbon dioxide.

[0020] By adopting the above technical solution, liquid nitrogen and liquid carbon dioxide do not react with n-butyl acetate.

[0021] The present invention is further configured as follows: the n-butyl acetate purification device also includes a decolorization preheating reactor, the expansion airbag is connected to the decolorization preheating reactor, a sixth shut-off valve for controlling the connection or cutoff between the decolorization preheating reactor and the expansion airbag is provided between the decolorization preheating reactor and the expansion airbag, and the decolorization preheating reactor is provided with a ventilation valve.

[0022] By adopting the above technical solution, the inflatable airbag can also perform ventilation operations on other equipment of n-butyl acetate.

[0023] The present invention has significant technical effects due to the adoption of the above technical scheme: the heat exchange tube is located in the condenser, and after the cold liquid enters the heat exchange tube, the steam can be cooled by the cold liquid, which has the effect of accelerating condensation. At the same time, part of the liquid nitrogen in the heat exchange tube is changed from liquid to gas due to heat absorption, and the gaseous nitrogen or carbon dioxide enters the distillation tower, which can discharge the oxygen in the distillation tower. After ventilation for a period of time, the distillation tower can be completely filled with nitrogen. The distillation tower after ventilation discharges most of the oxygen, which greatly reduces the possibility of combustion of n-butyl acetate. The cooling control module generates a cooling strategy according to the first temperature sensing subunit and the second temperature sensing subunit. The cooling control module is configured with a cooling strategy table. In order to obtain high-purity n-butyl acetate, the tower top temperature is controlled to be about 115-125°C, the tower bottom temperature is 130-150°C, the pressure is in the range of 0.1-0.5 MPa, and the boiling point is 120-130 ℃ fraction, thereby obtaining high-purity n-butyl acetate. A pressure detection element is arranged in the distillation tower to monitor the pressure in the distillation tower in real time. When the pressure in the distillation tower is less than 0.1MPa, the expansion airbag is driven to communicate with the distillation tower through the four-way reversing valve, and the expansion airbag can supplement the pressure of the distillation tower. When the pressure of the distillation tower is higher than 0.5MPa, the pressure relief operation can be performed by opening the exhaust valve of the distillation tower. The temperature of the layer plates at different heights of the distillation tower is also different. The temperature is controlled by controlling the temperature control heater of the layer plates. The temperature of the layer plates and the temperature of different heights of the distillation tower are controlled by aligning the first temperature sensing subunit and the second temperature sensing subunit. Monitoring ensures that the temperature of the distillation tower is within the required range. Layer plates at different heights are configured with different preset temperature ranges and cooling strategies. The cooling strategy is that when the second temperature sensing subunit detects that the layer plate exceeds the preset temperature range, the layer plate and the corresponding temperature control heater in the temperature control cabin are cooled. The cooling strategy is configured with a cooling strategy table. According to the temperature exceeding different preset temperature ranges, a small cooling strategy or a medium cooling strategy is selected, or the temperature control heater is turned off and a large cooling strategy is adopted, so as to avoid the vapor temperature of n-butyl acetate exceeding 370 degrees, reduce the ignition temperature of n-butyl acetate, and avoid the combustion of n-butyl acetate due to high heat energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of a n-butyl acetate purification device;

[0025] Figure 2 is an overall cross-sectional view of the distillation tower in Example 1;

[0026] Figure 3 yes Figure 2 The enlarged schematic diagram at A in the middle;

[0027] Figure 4 It is an overall cross-sectional view of the condenser in the first embodiment.

[0028] The names of the parts indicated by the numerical labels in the above drawings are as follows: 1. Distillation tower; 11. Tower body; 12. Layer tower plate; 13. Auxiliary cooling plate; 2. Temperature control device; 21. Cold liquid tank; 22. Temperature control cabin; 23. Cooling component; 231. Air shower cooling pipe; 232. Spray valve; 3. Condenser; 31. Condensation tank; 311. Steam inlet section; 312. Cooling section; 313. Liquefaction outflow section; 32. Steam pipe; 33. Heat exchange pipe; 34. Inlet one; 35. Outlet one; 4. Ventilation control module; 41. Expansion airbag; 42. Third control valve; 43. Exhaust valve; 44. Limit frame; 5. Decolorization preheating reactor. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0030] Embodiment 1:

[0031] A n-butyl acetate purification device, combined with Figure 1 , including a n-butyl acetate purification device, a temperature control device 2 and a temperature control system, the n-butyl acetate purification device includes a decolorization preheating reaction kettle 5, a distillation tower 1, a condenser 3 and a filter, the distillation tower 1 includes a tower body 11 and a layer tower plate 12 arranged in the tower body 11 and along the height direction of the tower body 11, the temperature control device 2 includes a cold liquid tank 21, a temperature control tank 22 and a cooling component 23, the temperature control tank 22 is wrapped around the outside of the tower body 11 and arranged along the height direction of the tower body 11, the tower body 11 is provided with a slot for installing the layer tower plate 12, and a sealing ring for sealing the layer tower 12 is provided at the slot, combined with Figure 3 The layer tower plate 12 partly extends out of the tower body 11 through the groove, and the part of the layer tower plate 12 extending out of the tower body 11 is located in the temperature control cabin 22. The layer tower plate 12 is made of metal material with good thermal conductivity. The part of the layer tower plate 12 located in the temperature control cabin 22 is provided with a temperature control heater. The temperature control heater adopts an existing electric heating plate with controllable heating temperature. The heating temperatures of the temperature control heaters of the layer tower plates 12 at different heights are different, and the temperature of the layer tower plates 12 at different heights is controlled by the temperature control heater.

[0032] See also Figure 1 and Figure 2 The cold liquid cabin 21 is arranged above the temperature control cabin 22. A high-pressure liquid storage tank for storing cold liquid is arranged in the cold liquid cabin 21. The liquid storage tank is provided with a discharge valve for cold liquid discharge. The cold liquid in this embodiment adopts liquid nitrogen, but it is not limited to liquid nitrogen and can also be other flame retardant refrigerants such as liquid carbon dioxide. Figure 3The cooling component 23 includes an air shower cooling pipe 231, a first shut-off valve and a second shut-off valve. The first shut-off valve is arranged between the cold liquid cabin 21 and the temperature control cabin 22 for connecting or shutting off the two. The second shut-off valve body is arranged between the air shower cooling pipe 231 and the cold liquid cabin 21 for connecting or shutting off the two. The air shower cooling pipe 231 is located in the temperature control cabin 22. The air shower cooling pipe 231 is arranged in the temperature control cabin 22. The air shower cooling pipe 231 is evenly spaced along the height direction. A plurality of spray valves are arranged 232, wherein some of the spray valves 232 are oriented toward the temperature control heater and the layer tower plate 12, an auxiliary cooling plate 13 is convexly provided on the distillation tower 1, the auxiliary cooling plate 13 is integrally formed with the tower body 11, and at least one auxiliary cooling plate 13 is provided on the upper and lower sides of the layer tower plate 12, wherein some of the spray valves 232 are oriented toward the temperature control heater and the layer tower plate 12, and the spray range of the spray valve 232 covers the auxiliary cooling plate 13, and the temperature control cabin 22 is provided with an overflow valve for pressure relief.

[0033] See also Figure 1 The distillation tower 1 is provided with steam outlets at different heights, and the steam outlets are provided with condensers 3 for converting the gas phase into the liquid phase. Figure 4 The condenser 3 includes a condenser tank 31, a steam pipe 32 arranged in the condenser tank 31, and a heat exchange pipe 33 for cooling the steam pipe 32. The condenser tank 31 includes a steam inlet section 311, a cooling section 312, and a liquefied outflow section 313. A plurality of steam pipes 32 are arranged in the cooling section 312. A cooling liquid is stored in the cooling section 312. In this embodiment, the cooling liquid is water, but it is not limited to water and other cooling liquids can be used. The heat exchange pipe 33 is arranged in the cooling section 312 in a reciprocating spiral shape. Part The heat exchange tube 33 and the steam pipe 32 are both immersed in the cooling liquid. The heat exchange tube 33 is provided with an inlet 34 and an outlet 35. The inlet 34 and the cold liquid tank 21 are connected by a connecting pipe. A shut-off valve for controlling the connection between the two or throttling is provided between the inlet 34 and the cold liquid tank 21. The cold liquid in the cold liquid tank 21 enters the heat exchange tube 33 through the connecting pipe. The cold liquid cools the steam pipe 32 in the heat exchange tube 33. The liquid nitrogen absorbs heat and vaporizes, changing from liquid to gas. The liquid nitrogen that has become gas can be discharged from the outlet 35.

[0034] See also Figure 1The distillation tower 1 is provided with a ventilation control module 4, which includes an exhaust subunit and an air intake subunit. The air intake subunit includes an expansion airbag 41 and a third control valve 42. The exhaust subunit includes an exhaust valve 43. The expansion airbag 41 can be elastically deformed to become larger or smaller according to the change of air pressure. The expansion airbag 41 is connected to the outlet 35 of the heat exchange tube 33. When the cold liquid in the heat exchange tube 33 is vaporized into gas, the air pressure increases so that the expansion airbag 41 can be inflated. A limiting frame 44 is arranged outside the expansion airbag 41. The limiting frame 44 is used to limit the maximum expansion volume of the expansion airbag 41 to avoid dangerous events such as rupture of the expansion airbag 41 due to excessive volume.

[0035] See also Figure 1 The third control valve 42 is arranged between the expansion airbag 41 and the distillation tower 1. The third control valve 42 adopts a four-way reversing valve. The four-way reversing valve is provided with four valve ports, which are respectively connected to the expansion airbag 41, the distillation tower 1, the air shower cooling pipe 231 and the pressure relief pipe. The remaining valve port is connected to the pressure relief tail gas pipe. The reversing valve can be used to switch the four valve ports. When the distillation tower 1 needs to be ventilated, the four-way reversing valve drives the expansion airbag 41 to communicate with the distillation tower 1, and the nitrogen in the gasified state in the expansion airbag 41 enters the distillation tower 1 through the third control valve 42, and the exhaust valve 43 of the exhaust subunit on the distillation tower 1 is opened, thereby completing the ventilation operation of the distillation tower 1 and minimizing the oxygen concentration in the distillation tower 1. When the expansion airbag 41 is connected to the air shower cooling pipe 231, the second shut-off valve of the air shower cooling pipe 231 is in a cut-off state. At this time, the spray valve 232 is opened to blow air to cool the temperature control heater, which can be used for small-scale cooling. When medium-scale cooling is required, the second shut-off valve can be opened. At this time, the spray valve 232 is opened for synchronous spraying of gas and liquid, which can be used for medium-scale cooling. When the expansion airbag 41 is not connected to the air shower cooling pipe 231, the first shut-off valve and the second shut-off valve are in an open state. At this time, the spray valve 232 is opened for spraying cold liquid, which can be used for large-scale cooling. When the air pressure in the expansion airbag 41 is too high, the four-way reversing valve can control the expansion airbag 41 to be connected to the pressure relief tail pipe, which can relieve the pressure on the expansion airbag 41.

[0036] The decolorization and preheating reactor 5 includes a reactor body, a stirring assembly, a preheating assembly and a multi-layer filter plate arranged on the reactor body. An exhaust subunit is also arranged on the reactor body. A sixth shut-off valve is arranged between the expansion air bag 41 and the reactor body of the decolorization and preheating reactor 5. The sixth shut-off valve is used to connect or cut off the expansion air bag 41 and the reactor body. The exhaust subunit of the decolorization and preheating reactor 5, the exhaust subunit of the distillation tower 1, the pressure relief tail gas pipe connected to the third control valve 42 and the overflow valve on the temperature control cabin 22 are all connected to the waste gas treatment unit. The waste treatment unit is a prior art in the distillation process and will not be elaborated on again.

[0037] The temperature control system is equipped with a temperature monitoring module and a temperature reduction control module. The temperature monitoring module includes a plurality of first temperature sensing subunits and a plurality of second temperature sensing subunits. The plurality of first temperature sensing subunits are evenly spaced along the height direction of the inner wall of the distillation tower 1. The plurality of second temperature sensing subunits correspond to a plurality of temperature control heaters one by one. The temperature reduction control module generates a temperature reduction strategy according to the first temperature sensing subunit and the second temperature sensing subunit. The temperature reduction control module is equipped with a temperature reduction strategy table. In order to obtain high-purity n-butyl acetate, the tower top temperature is controlled to be about 115-125°C, the tower bottom temperature is 130-150°C, the pressure is within the range of 0.1-0.5 MPa, and the boiling point is collected to be 120-130 ℃ fraction, thereby obtaining high-purity n-butyl acetate, a pressure detection element is arranged in the distillation tower 1, which is used to monitor the pressure in the distillation tower 1 in real time, when the pressure in the distillation tower 1 is less than 0.1 MPa, the expansion airbag 41 is driven to communicate with the distillation tower 1 through the four-way reversing valve, and the expansion airbag 41 can supplement the pressure of the distillation tower 1, and when the pressure of the distillation tower 1 is higher than 0.5 MPa, the pressure relief operation can be performed by opening the exhaust valve 43 of the distillation tower 1, and the temperature of the layer plates 12 at different heights of the distillation tower 1 is also different, and the temperature is controlled by controlling the temperature control heater of the layer plate 12, and the temperature of the layer plate 12 and the temperature of different heights of the distillation tower 1 are monitored by aligning the first temperature sensing subunit and the second temperature sensing subunit to ensure that the temperature of the distillation tower 1 is within the required range, and the layer plates 12 at different heights are configured with different preset temperature ranges and cooling strategies, and the cooling strategy is that when the second temperature sensing subunit detects that the layer plate 12 exceeds the preset The temperature range is to cool down the layer tower plate 12 and the corresponding temperature control heater located in the temperature control chamber 22. The cooling strategy is configured with a cooling strategy table. When the temperature exceeds the preset temperature range by less than 50%, a small cooling strategy is adopted. When the temperature exceeds the preset range by less than one time, a medium cooling strategy is adopted. When the temperature exceeds the preset temperature by one time or more, the temperature control heater is turned off and a large cooling strategy is adopted, thereby preventing the vapor temperature of n-butyl acetate from exceeding 370 degrees, reducing the ignition temperature of n-butyl acetate, and avoiding the combustion of n-butyl acetate due to high heat energy.

[0038] The strategy for small-scale cooling is to connect the expansion airbag 41 with the air shower cooling pipe 231, and the second shut-off valve of the air shower cooling pipe 231 is in the cut-off state. At this time, the spray valve 232 is opened to blow air to cool the temperature-controlled heater, and air cooling is adopted; the strategy for medium-scale cooling is to open the second shut-off valve, connect the expansion airbag 41 with the air shower cooling pipe 231, and at this time, open the spray valve 232 to spray gas and liquid synchronously for cooling; for large-scale cooling, the first shut-off valve and the second shut-off valve are both in the open state, or only the first shut-off valve is in the open state, and the cold liquid in the cold liquid compartment 21 directly enters Inside the temperature control valve, the temperature control heater and the layer tower plate 12 extending into the temperature control chamber 22 are caused to cool down instantly, thereby generating different cooling strategies according to the temperatures sensed by the first temperature sensing sub-unit and the second temperature sensing sub-unit. The cooling control module controls the components in the cooling assembly 23 according to the cooling strategy. When only one or several temperature control heaters exceed the preset temperature range, the second shut-off valve opens, and only the spray valve 232 corresponding to the temperature control heater exceeding the preset temperature on the air shower cooling pipe 231 works, and the air shower cooling pipe 231 can perform separate cooling treatment on some temperature control heaters.

[0039] Embodiment 2:

[0040] The difference between this embodiment and the first embodiment is that the third control valve 42 in this embodiment adopts a shut-off valve to connect or cut off the expansion airbag 41 and the distillation tower 1. When the third control valve 42 is opened, the nitrogen in the gasified state in the expansion airbag 41 enters the distillation tower 1 through the third control valve 42, and the exhaust valve 43 of the exhaust subunit on the distillation tower 1 is opened, thereby completing the ventilation operation of the distillation tower 1 and minimizing the oxygen concentration in the distillation tower 1.

Claims

1. A n-butyl acetate purification device, comprising an n-butyl acetate purification device, a temperature control device (2) and a temperature control system, wherein the n-butyl acetate purification device comprises a distillation tower (1) and a condenser (3), wherein the distillation tower (1) is provided with a plurality of trays (12), and the condenser (3) is provided with a heat exchange tube (33), characterized in that: The temperature control device (2) comprises a cold liquid tank (21), a temperature control tank (22) arranged along the height direction of the distillation tower (1), and a cooling component (23); a plurality of the layer trays (12) extend into the temperature control tank (22); a temperature control heater is arranged at the layer trays (12) located in the temperature control tank (22); the temperature control heater is used to heat the layer trays (12) located in the temperature control tank (22); the cooling component (23) comprises an air shower cooling pipe (231) and a second shut-off valve arranged in the temperature control tank (22); the air shower cooling pipe (231) is provided with a plurality of spray valves (232) opposite to the temperature control heater; the second shut-off valve is arranged between the air shower cooling pipe (231) and the cold liquid tank (21) for connecting or shutting off the two; the heat exchange pipe (33) is connected to the cold liquid tank (21); and cold liquid can be stored in the cold liquid tank (21); The distillation tower (1) is provided with a ventilation control module (4), the ventilation control module (4) comprises an air intake subunit, the air intake subunit comprises an expansion airbag (41) and a third control valve (42), the heat exchange pipe (33) is connected to the expansion airbag (41), the third control valve (42) is arranged between the expansion airbag (41) and the distillation tower (1), and the third control valve (42) is used to connect or cut off the expansion airbag (41) and the distillation tower (1); The cold liquid chamber (21) is arranged above the temperature control chamber (22), and the cooling component (23) further comprises a first shut-off valve, which is arranged between the cold liquid chamber (21) and the temperature control chamber (22) and is used to connect or cut off the two. The temperature control system is equipped with a temperature monitoring module and a temperature reduction control module, the temperature monitoring module includes a plurality of first temperature sensing sub-units and a plurality of second temperature sensing sub-units, the plurality of first temperature sensing sub-units are arranged at intervals along the height direction of the inner wall of the distillation tower (1), and the second temperature sensing sub-units are used to correspond one by one to the temperature control heaters; The cooling control module generates a cooling strategy according to the first temperature sensing subunit and the second temperature sensing subunit; The cooling control module is configured with a cooling strategy table, wherein the cooling strategy table is configured with a small cooling strategy, a medium cooling strategy and a large cooling strategy according to different degrees of exceeding the preset temperature. The small cooling strategy uses an expansion air bag (41) connected to the air shower cooling pipe (231) to cool down, the medium cooling strategy uses an expansion air bag (41) connected to the air shower cooling pipe (231) and opens the second shut-off valve to cool down, and the large cooling strategy uses the first shut-off valve to cool down.

2. A n-butyl acetate purification device according to claim 1, characterized in that: The ventilation control module (4) further comprises an exhaust subunit, wherein the exhaust subunit and the air intake subunit are both arranged in the distillation tower (1), the exhaust subunit is used to discharge the gas in the distillation tower (1), and the air intake subunit is connected to the heat exchange pipe (33), and the gas passing through the heat exchange pipe (33) enters the distillation tower (1) through the air intake subunit.

3. A n-butyl acetate purification device according to claim 1, characterized in that: The third control valve (42) is a four-way reversing valve, which is provided with four valve ports, and the four valve ports are respectively connected to the expansion airbag (41), the distillation tower (1), the air shower cooling pipe (231) and the pressure relief tail gas pipe.

4. A n-butyl acetate purification device according to claim 1, characterized in that: The n-butyl acetate purification device also includes a decolorization preheating reactor (5), the expansion air bag (41) is connected to the decolorization preheating reactor (5), a sixth shut-off valve for controlling the connection or cut-off between the decolorization preheating reactor (5) and the expansion air bag (41) is provided between the decolorization preheating reactor (5) and the expansion air bag (41), and the decolorization preheating reactor (5) is provided with a ventilation valve.

5. The n-butyl acetate purification device according to claim 1, characterized in that: A plurality of auxiliary cooling plates (13) are arranged in the temperature control chamber (22); the auxiliary cooling plates (13) are fitted to or integrally formed with the inner wall of the distillation tower (1); the auxiliary cooling plates (13) are arranged on both sides of the layer tower plate (12); and the spray valve (232) can spray the auxiliary cooling plates (13) synchronously.

6. The n-butyl acetate purification device according to claim 1, characterized in that: The cooling liquid is liquid nitrogen or liquid carbon dioxide.

7. The n-butyl acetate purification device according to claim 1, characterized in that: A limiting frame (44) for limiting the maximum expansion volume of the expansion airbag (41) is arranged outside the expansion airbag (41).

Images