A method for butyl acetate rectification

Abstract

The application provides a butyl acetate rectification method, which comprises the following steps: butyl acetate raw solution is preheated and then enters a rectification tower; high-concentration butyl acetate steam is discharged from the top of the tower and then enters a shell side of a waste heat recovery device, and tower bottom liquid is punched into a hot stream inlet of a preheating subsystem; the material in the tube side of the waste heat recovery device exchanges heat with the steam in the shell side under the driving of a circulating pump, the material in the tube side is boiled and evaporated after heat exchange, the generated gas-liquid mixture enters a purifier to be separated, the steam in the purifier enters an enthalpy booster from the top, is lifted in grade after the enthalpy is increased, and then enters the tower bottom of the rectification tower to participate in heat and mass transfer, and the liquid phase returns to the waste heat recovery device to participate in heat exchange and evaporation; the liquid from the hot stream outlet of the preheating subsystem enters a cooling subsystem, is separated by standing and layering, high-concentration butyl acetate solution is obtained from the upper layer, and the lower layer is an aqueous phase. The tower top condenser is omitted, the cooling water consumption is reduced, and the energy consumption of the butyl acetate rectification process is effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of butyl acetate treatment technology, and more particularly to a butyl acetate distillation method. Background Technology

[0002] Butyl acetate is an important basic chemical raw material, widely used as an organic solvent and extractant in the food and pharmaceutical industries due to its excellent physical properties. Therefore, the recycling and reuse of butyl acetate is a crucial step in the production process, effectively reducing production costs and carbon emissions.

[0003] Currently, simple distillation or rectification processes are commonly used to purify and recover butyl acetate. This system uses external live steam as a heat source. Although the system waste heat is utilized in a simple way by means of preheating the feed, most of the heat is still carried away by the cooling water, resulting in relatively high system energy consumption and operating costs. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art, and proposes a method for distillation of butyl acetate.

[0005] This invention provides a method for distilling butyl acetate, the method comprising:

[0006] The butyl acetate stock solution is preheated via a preheating subsystem before entering the distillation column;

[0007] The preheated butyl acetate stock solution is distilled using the distillation column. High-concentration butyl acetate vapor is discharged from the top of the distillation column and enters the shell side of the waste heat recovery unit. The bottom liquid is pumped into the heat flow inlet of the preheating subsystem by the bottom liquid pump.

[0008] In the waste heat recovery unit, the tube-side material exchanges heat with the shell-side steam under the drive of the circulating pump. After the heat exchange, the tube-side material boils and evaporates, and the resulting vapor-liquid mixture enters the purifier for vapor-liquid separation. The shell-side steam condenses into liquid and enters the condensate tank.

[0009] The vapor phase in the purifier enters the enthalpy enhancer from its top. After the enthalpy is increased and the grade is improved, it enters the distillation column from the bottom of the column to participate in heat and mass transfer. The liquid phase is returned to the waste heat recovery process unit to participate in heat exchange and evaporation.

[0010] The liquid in the condensate tank is pumped into the heat inlet of the preheating subsystem as a heat source for preheating the feed. The liquid at the heat outlet of the preheating subsystem enters the cooling subsystem. After settling and stratification, the upper layer is a high-concentration butyl acetate solution and the lower layer is an aqueous phase, thus completing the distillation of butyl acetate.

[0011] Optionally, the preheating subsystem includes a non-condensable steam preheater, a condensate preheater, a first column bottom liquid preheater, a second column bottom liquid preheater, and a steam ejector; the step of preheating the butyl acetate stock solution via the preheating subsystem before entering the distillation column includes:

[0012] The butyl acetate stock solution is injected into the cold flow inlet of the non-condensable steam preheater for initial preheating.

[0013] After preheating, the butyl acetate stock solution enters the condensate preheater for further preheating and is then discharged from the cold flow outlet.

[0014] The discharged butyl acetate raw liquid successively enters the first column bottom liquid preheater and the second column bottom liquid preheater for preheating and temperature rise, and then enters the steam ejector. After being ejected by external high-pressure live steam, it enters the distillation column.

[0015] Optionally, the method further includes:

[0016] The excess liquid in the purifier is pumped into the first column bottom liquid preheater for preheating before being discharged into the column bottom liquid storage tank.

[0017] Optionally, the cooling subsystem includes a cooler and a phase-separating tank. The liquid in the condensate tank is pumped into the heat inlet of the preheating subsystem as a heat source to preheat the feed. The liquid from the heat outlet of the preheating subsystem enters the cooling subsystem. After settling and stratification, the upper layer is a high-concentration butyl acetate solution, and the lower layer is an aqueous phase, completing the distillation of butyl acetate, including:

[0018] The liquid in the condensate tank is pumped into the heat flow inlet of the condensate preheater as a heat source to preheat the feed.

[0019] The liquid from the hot flow outlet of the condensate preheater is further cooled by the cooler and then enters the phase separation tank. After settling and stratification, the upper layer is a high-concentration butyl acetate solution and the lower layer is an aqueous phase.

[0020] Optionally, before introducing the liquid from the hot outlet of the condensate preheater into the cooler, the method further includes:

[0021] Uncondensed steam from the shell side of the waste heat recovery unit and the top of the condensate tank is collected uniformly;

[0022] The collected non-condensable steam is heated in a non-condensable steam preheater and condensed into liquid. Then, it enters the cooler together with the liquid from the hot flow outlet of the condensate preheater.

[0023] Optionally, the temperature ranges of the butyl acetate stock solution after preheating by the non-condensable steam preheater, condensate preheater, first tower bottom liquid preheater, and second tower bottom liquid preheater are 20℃~30℃, 35℃~40℃, 50℃~60℃, and 70℃~90℃, respectively; and,

[0024] The heat flow side temperature ranges of the non-condensable steam preheater, condensate preheater, first tower bottom liquid preheater, and second tower bottom liquid preheater after heat exchange are 60℃~70℃, 50℃~55℃, 65℃~75℃, and 75℃~95℃, respectively.

[0025] Optionally, the temperature range of the butyl acetate stock solution after preheating by the steam injector is 92℃~98℃.

[0026] Optionally, the temperature range of the high-concentration butyl acetate vapor is 90℃~100℃.

[0027] Optionally, the temperature range for the boiling and evaporation of the tube-side material after heat exchange is 75℃~95℃.

[0028] Optionally, the vapor phase in the purifier is pressurized to 110 kPa to 200 kPa via an enthalpy enhancer.

[0029] The beneficial effects of this invention are as follows:

[0030] The butyl acetate distillation method of the present invention is reasonably designed and has a simple structure. In the method, the bottom liquid of the column is used as the heat transfer medium. The waste heat of the top vapor of the column is recovered and utilized through the interaction between the low temperature bottom liquid and the enthalpy enhancer. At the same time, the top condenser can be eliminated, the consumption of circulating cooling water is reduced, and the energy consumption of the butyl acetate distillation process is effectively reduced. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a butyl acetate distillation system according to an embodiment of the present invention;

[0032] Figure 2 This is a flowchart of a butyl acetate distillation method according to an embodiment of the present invention. Detailed Implementation

[0033] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Embodiments of the present invention relate to a method for distilling butyl acetate, which is applied to a butyl acetate distillation system, such as... Figure 1 As shown, the system includes a preheating subsystem, a distillation subsystem, an evaporation subsystem, and a cooling subsystem. The distillation subsystem includes a distillation column 7 and a bottom liquid pump 16. The evaporation subsystem includes a waste heat recovery unit 8, a purifier 9, an enthalpy enhancer 10, a condensate tank 11, a condensate pump 17, a circulation pump 18, an upper circulation pipe 20, and a lower circulation pipe 21.

[0037] For example, such as Figure 1 As shown, the cold flow inlet of the preheating subsystem is used to receive butyl acetate stock solution, the cold flow outlet of the preheating subsystem is connected to the inlet of the distillation column 7, and the hot flow outlet of the preheating subsystem is connected to the inlet of the cooling subsystem.

[0038] Continue to refer to Figure 1 The top vapor outlet of the distillation column 7 is connected to the shell-side heat inlet of the waste heat recovery unit 8. The bottom heating steam inlet of the distillation column 7 is connected to the outlet of the enthalpy enhancer 10. The bottom liquid outlet of the distillation column 7 is connected to the inlet of the bottom liquid pump 16, and the outlet of the bottom liquid pump 16 is connected to the heat inlet of the preheating subsystem. The distillation column 7 is an essential column-type gas-liquid contact device in the distillation system, utilizing the different volatility of the components in the mixture to achieve the separation of various substances with different boiling points. In this embodiment, the distillation column 7 is preferably a tray type, but packed or mixed distillation columns can also be used.

[0039] For example, such as Figure 1As shown, the inlet of the waste heat recovery unit 8 is connected to the outlet of the circulating pump 18. The vapor-liquid two-phase outlet of the waste heat recovery unit 8 is connected to the vapor-liquid two-phase inlet of the purifier 9 through the upper circulating pipe 20. The liquid phase outlet of the waste heat recovery unit 8 is connected to the liquid phase outlet of the purifier 9 through the lower circulating pipe 21. The shell-side non-condensable vapor outlet of the waste heat recovery unit 8 is connected to the top non-condensable vapor outlet of the condensate tank 11. The shell-side liquid phase outlet of the waste heat recovery unit 8 is connected to the liquid phase inlet of the condensate tank 11. The liquid phase outlet of the condensate tank 11 is connected to the inlet of the condensate pump 17. The outlet of the condensate pump 17 is connected to the heat flow inlet of the preheating subsystem. The vapor phase outlet of the purifier 9 is connected to the inlet of the enthalpy enhancer 10. The lower circulating pipe 21 is also connected to the inlet of the circulating pump 18.

[0040] In this embodiment, the waste heat recovery unit 8 is a key heat exchange device in the butyl acetate heat pump distillation system, used for heat exchange between the top steam and the bottom liquid after flash cooling; the waste heat recovery unit 8 is preferably a falling film waste heat recovery unit, but a forced circulation waste heat recovery unit or a natural circulation waste heat recovery unit can also be used, and the waste heat recovery unit can be a shell and tube heat exchanger or a plate heat exchanger.

[0041] In this embodiment, the purifier 9 is used to separate the vapor-liquid mixture obtained from the evaporation process, employing gravity separation. A cyclone separator or wire mesh packing can be installed in the vapor phase to further remove entrained droplets. The enthalpy enhancer 10 is used for the recovery and reheating of secondary steam for reuse.

[0042] Next, as Figure 2 As shown, a method for distilling butyl acetate includes the following specific steps:

[0043] Step 101: The butyl acetate stock solution is preheated by the preheating subsystem and then fed into the distillation column.

[0044] Step 102: The preheated butyl acetate stock solution is distilled using the distillation column. The high-concentration butyl acetate vapor is discharged from the top of the distillation column and enters the shell side of the waste heat recovery unit. The bottom liquid is pumped into the heat flow inlet of the preheating subsystem by the bottom liquid pump.

[0045] Step 103: The tube-side material of the waste heat recovery unit exchanges heat with the shell-side steam under the drive of the circulating pump. After the heat exchange, the tube-side material boils and evaporates. The resulting vapor-liquid mixture enters the purifier for vapor-liquid separation, and the shell-side steam condenses into liquid and enters the condensate tank.

[0046] Step 104: The vapor phase in the purifier enters the enthalpy enhancer from its top. After the enthalpy is increased and the grade is improved, it enters the column from the bottom of the distillation column to participate in heat and mass transfer. The liquid phase is returned to the waste heat recovery process unit to participate in heat exchange and evaporation.

[0047] Step 105: The liquid in the condensate tank is pumped into the heat inlet of the preheating subsystem as a heat source to preheat the feed. The liquid at the heat outlet of the preheating subsystem enters the cooling subsystem. After settling and stratification, the upper layer is a high-concentration butyl acetate solution and the lower layer is an aqueous phase, thus completing the distillation of butyl acetate.

[0048] The butyl acetate distillation method of this invention is reasonably designed and has a simple structure. The method uses the bottom liquid of the column as the heat transfer medium and realizes the recovery and utilization of the exhaust heat of the top vapor through the interaction between the low temperature bottom liquid and the enthalpy enhancer. At the same time, the top condenser can be eliminated, reducing the consumption of circulating cooling water and effectively reducing the energy consumption of the butyl acetate distillation process.

[0049] For example, such as Figure 1 As shown, the preheating subsystem includes a non-condensable steam preheater 2, a condensate preheater 3, a first tower bottom liquid preheater 4, a second tower bottom liquid preheater 5, and a steam ejector 6. The system also includes a raw liquid storage tank 1 and a feed pump 15. The inlet of the feed pump 15 is connected to the material outlet of the raw liquid storage tank 1, and the outlet of the feed pump 15 is connected to the cold flow inlet of the non-condensable steam preheater 2.

[0050] The cold flow inlet of the non-condensable steam preheater 2 is used to receive butyl acetate raw liquid. The cold flow outlet of the non-condensable steam preheater 2 is connected to the cold flow inlet of the condensate preheater 3. The cold flow outlet of the condensate preheater 3 is connected to the cold flow inlet of the first bottom liquid preheater 4. The cold flow outlet of the first bottom liquid preheater 4 is connected to the cold flow inlet of the second bottom liquid preheater 5. The cold flow outlet of the second bottom liquid preheater 5 is connected to the first inlet of the steam ejector 6. The second inlet of the steam ejector 6 is used to connect to an external high-pressure live steam pipeline. The outlet of the steam ejector 6 is connected to the material inlet of the distillation column 7.

[0051] Step 101 above specifically includes:

[0052] The butyl acetate stock solution is initially preheated by being fed into the cold inlet of the non-condensable steam preheater, with a preheated temperature range of 20℃ to 30℃. After preheating, the butyl acetate stock solution enters the condensate preheater for further preheating before being discharged from the cold outlet, with a preheated temperature range of 35℃ to 40℃. The discharged butyl acetate stock solution subsequently enters the first column bottom liquid preheater (preheated temperature range of 50℃ to 60℃) and the second column bottom liquid preheater, where it is further preheated (preheated temperature range of 70℃ to 90℃) before entering the steam ejector. After being ejected by external high-pressure live steam, it enters the distillation column, with the butyl acetate stock solution preheated by the steam ejector reaching a temperature range of 92℃ to 98℃. The heat flow side temperature ranges of the non-condensable steam preheater, condensate preheater, first tower bottom liquid preheater, and second tower bottom liquid preheater after heat exchange are 60℃~70℃, 50℃~55℃, 65℃~75℃, and 75℃~95℃, respectively.

[0053] In this embodiment, the preheater is used for feed preheating and system waste heat recovery processes, improving system energy efficiency and operational stability. The preheaters used in this system are preferably shell-and-tube heat exchangers, but plate heat exchangers or spiral plate heat exchangers can also be used. The steam ejector 6 uses external high-pressure steam to inject the material into the distillation column, simultaneously heating the feed.

[0054] For example, such as Figure 1 As shown, the system also includes an external discharge pump 19 and a bottom liquid storage tank 12. The inlet of the external discharge pump 19 is connected to the liquid outlet of the purifier 9, the outlet of the external discharge pump 19 is connected to the hot flow inlet of the first bottom liquid preheater 4, and the discharge outlet of the first bottom liquid preheater 4 is connected to the inlet of the bottom liquid storage tank 12.

[0055] Furthermore, the above method also includes:

[0056] Excess liquid in the purifier is pumped into the first column bottom liquid preheater to preheat the feed before being discharged into the column bottom liquid storage tank. This further reduces the consumption of circulating cooling water and effectively lowers the energy consumption of the butyl acetate distillation process.

[0057] For example, such as Figure 1 As shown, the cooling subsystem includes a cooler 13 and a phase-separating tank 14. The cold flow inlet of the cooler 13 is connected to the external circulating water inlet, and the cold flow outlet of the cooler 13 is connected to the external circulating water return. The material outlet of the cooler 13 is connected to the material inlet of the phase-separating tank 14. The top of the phase-separating tank 14 is provided with a butyl acetate outlet pipe, and the bottom of the phase-separating tank is provided with a water outlet pipe.

[0058] Furthermore, step 105 above includes:

[0059] The liquid in the condensate tank is pumped into the heat flow inlet of the condensate preheater as a heat source to preheat the feed.

[0060] The liquid from the hot flow outlet of the condensate preheater is further cooled by the cooler and then enters the phase separation tank. After settling and stratification, the upper layer is a high-concentration butyl acetate solution and the lower layer is an aqueous phase.

[0061] For example, such as Figure 1 As shown, the heat inlet of the non-condensable steam preheater 2 is connected to the shell side of the waste heat recovery unit 8 and the non-condensable steam outlet of the condensate tank 11, respectively; the outlet of the condensate pump 17 is connected to the heat inlet of the condensate preheater 3. The heat outlet of the condensate preheater 3 is connected to the heat outlet of the non-condensable steam preheater 2, and then the heat flow converges into the heat inlet of the cooler 13. The outlet of the bottom liquid pump 16 is connected to the heat inlet of the second tower bottom liquid preheater 5, and the heat outlet of the second tower bottom liquid preheater 5 is connected to the tube-side material inlet of the waste heat recovery unit 8.

[0062] Furthermore, before introducing the liquid from the hot outlet of the condensate preheater into the cooler, the method further includes:

[0063] Uncondensed steam from the shell side of the waste heat recovery unit and the top of the condensate tank is collected uniformly;

[0064] The collected non-condensable steam is heated in a non-condensable steam preheater and condensed into liquid. Then, it enters the cooler together with the liquid from the hot flow outlet of the condensate preheater.

[0065] In some embodiments, the temperature range of the high-concentration butyl acetate vapor obtained after distillation of the preheated butyl acetate stock solution is 90°C to 100°C. In the tube side of the waste heat recovery unit, the temperature range of the boiling evaporation of the material after heat exchange is 75°C to 95°C. The vapor phase in the purifier is pressurized to 110 kPa to 200 kPa via an enthalpy enhancer and then used for heating the bottom liquid of the distillation column.

[0066] The following is combined Figure 1 The distillation method for butyl acetate in this embodiment will be described in detail.

[0067] The butyl acetate raw liquid is discharged from the material outlet of the raw liquid storage tank 1 and pumped into the cold flow inlet of the non-condensable vapor preheater 2 by the feed pump 15 for initial preheating. Subsequently, the material enters the condensate preheater 3 for further preheating and is discharged from the cold flow outlet. Further, the material successively enters the first column bottom liquid preheater 4 and the second column bottom liquid preheater 5 for preheating and then enters the steam ejector 6. After being ejected by external high-pressure live steam, it enters the distillation column 7 and exchanges heat and mass with the material in the column to achieve separation and purification. The high-concentration butyl acetate vapor is discharged from the top of the distillation column 7 and enters the shell side of the waste heat recovery unit 8. The column bottom liquid is pumped into the hot flow inlet of the second column bottom liquid preheater 5 by the bottom liquid pump 16 as a heat source to heat the feed and reduce it to the set temperature before entering the tube side of the waste heat recovery unit 8. Driven by the circulating pump, the tube-side material exchanges heat with the shell-side vapor. After the heat exchange, the tube-side material boils and evaporates. The resulting vapor-liquid mixture enters the purifier 9 through the upper circulating pipe 20 for vapor-liquid separation. The shell-side vapor condenses into liquid and enters the condensate tank 11. In the purifier 9, the vapor phase enters the enthalpy enhancer 10 from the top. After the enthalpy is increased and the grade is improved, it enters the column from the bottom of the distillation column 7 to participate in heat and mass transfer. The liquid phase returns to the waste heat recovery process unit 8 through the lower circulation pipe 21 to participate in heat exchange and evaporation. The excess liquid is pumped into the first column bottom liquid preheater 4 by the external discharge pump 19 to preheat the feed and then discharged into the column bottom liquid storage tank 12. The liquid in the condensate tank 11 is pumped into the hot flow inlet of the condensate preheater 3 by the condensate pump 17 as a heat source to preheat the feed. In the above steam condensation process, there is some uncondensed steam. It is collected by the shell side of the waste heat recovery unit 8 and the top of the condensate tank 11 and enters the non-condensable steam preheater 2 to heat the feed and condense it into liquid. Then, together with the liquid at the hot flow outlet of the condensate preheater 3, it enters the cooler for further cooling and then enters the phase separation tank 14. After settling and stratification, the upper layer is a high-concentration butyl acetate solution and the lower layer is an aqueous phase.

[0068] In summary, the butyl acetate distillation method of this embodiment is reasonably designed and has a simple structure. The system uses the bottom liquid of the column as the heat transfer medium, and the waste heat of the top vapor is recovered and utilized through the interaction between the low-temperature bottom liquid and the enthalpy enhancer. At the same time, the top condenser can be eliminated, reducing the consumption of circulating cooling water and effectively reducing the energy consumption of the butyl acetate distillation process.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for rectifying butyl acetate, characterized by, The method comprises: The butyl acetate crude liquid is preheated by a preheating subsystem and then enters a rectifying tower; The preheated butyl acetate crude liquid is subjected to rectification treatment by the rectifying tower, high-concentration butyl acetate vapor is discharged from the top of the rectifying tower and then enters a waste heat recovery shell side, and tower bottom liquid is pumped by a tower bottom liquid pump and then enters a hot stream inlet of the preheating subsystem; The tube side material of the waste heat recovery device exchanges heat with the shell side vapor under the driving of a circulating pump, and after heat exchange, the tube side material is boiled and evaporated to generate a vapor-liquid mixture which enters a purifier to be subjected to vapor-liquid separation, and the shell side vapor is condensed into liquid which enters a condensate tank; The vapor phase in the purifier enters an enthalpy-increasing device from the top thereof, is upgraded in grade after increasing the enthalpy, and then enters the tower bottom of the rectifying tower to participate in heat and mass transfer in the tower, and the liquid phase returns to the waste heat recovery process device to participate in heat exchange and evaporation; The liquid in the condensate tank is pumped into the hot stream inlet of the preheating subsystem as a heat source to preheat the feed, and the liquid at the hot stream outlet of the preheating subsystem enters a cooling subsystem, is subjected to static stratification, and then high-concentration butyl acetate solution is obtained in the upper layer and water phase is obtained in the lower layer, thereby completing the rectification of butyl acetate; The preheating subsystem comprises a non-condensable vapor preheater, a condensate preheater, a first tower bottom liquid preheater, a second tower bottom liquid preheater, and a steam ejector; and the butyl acetate crude liquid is preheated by the preheating subsystem and then enters the rectifying tower, which comprises: The butyl acetate crude liquid is pumped into the cold stream inlet of the non-condensable vapor preheater to be subjected to preliminary preheating; The preheated butyl acetate crude liquid enters the condensate preheater to be further preheated and then is discharged from the cold stream outlet; The discharged butyl acetate crude liquid successively enters the first tower bottom liquid preheater and the second tower bottom liquid preheater to be preheated and warmed, and then enters the steam ejector after being injected by external high-pressure live steam, and then enters the rectifying tower; The preheated butyl acetate crude liquid is preheated by the non-condensable vapor preheater, the condensate preheater, the first tower bottom liquid preheater, and the second tower bottom liquid preheater, and the temperature ranges of the butyl acetate crude liquid preheated by the non-condensable vapor preheater, the condensate preheater, the first tower bottom liquid preheater, and the second tower bottom liquid preheater are respectively 20-30℃, 35-40℃, 50-60℃, and 70-90℃; and The non-condensable vapor preheater, the condensate preheater, the first tower bottom liquid preheater, and the second tower bottom liquid preheater exchange heat, and the temperature ranges of the hot stream sides of the non-condensable vapor preheater, the condensate preheater, the first tower bottom liquid preheater, and the second tower bottom liquid preheater are respectively 60-70℃, 50-55℃, 65-75℃, and 75-95℃.

2. The method of claim 1, wherein, The method further comprises: The excess liquid in the purifier is pumped into the first tower bottom liquid preheater to preheat the feed and then is discharged into a tower bottom liquid storage tank.

3. The method of claim 2, wherein, The cooling subsystem comprises a cooler and a phase separation tank, the liquid in the condensate tank is pumped into the hot stream inlet of the preheating subsystem as a heat source to preheat the feed, the liquid at the hot stream outlet of the preheating subsystem enters the cooling subsystem, is subjected to static stratification, and then high-concentration butyl acetate solution is obtained in the upper layer and water phase is obtained in the lower layer, thereby completing the rectification of butyl acetate, which comprises: The liquid in the condensate tank is pumped into the hot stream inlet of the condensate preheater as a heat source to preheat the feed; The liquid at the hot stream outlet of the condensate preheater enters the cooler to be further cooled, and then enters the phase separation tank, is subjected to static stratification, and then high-concentration butyl acetate solution is obtained in the upper layer and water phase is obtained in the lower layer.

4. The method of claim 3, wherein, Before the liquid at the hot stream outlet of the condensate preheater enters the cooler, the method further comprises: Collecting the non-condensed steam from the top of the condensate tank and the shell side of the heat recovery unit; The collected non-condensed steam is condensed into liquid after being heated by the non-condensing preheater, and then enters the cooler together with the liquid from the hot stream outlet of the condensate preheater.

5. The method according to any one of claims 1 to 4, characterized in that, The temperature of the butyl acetate solution after being preheated by the steam ejector ranges from 92℃ to 98℃.

6. The method according to any one of claims 1 to 4, characterized in that, The temperature of the high-concentration butyl acetate vapor ranges from 90℃ to 100℃.

7. The method according to any one of claims 1 to 4, characterized in that, The temperature of the tube side material after heat exchange and boiling evaporation ranges from 75℃ to 95℃.

8. The method according to any one of claims 1 to 4, characterized in that, The vapor phase in the purifier is pressurized to 110kPa to 200kPa by the enthalpy booster.

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