2-thiophene ethanol rectification system

Abstract

The utility model provides 2 - thiophene ethanol rectification system relates to the chemical production technical field, through the new three - stage preheater, utilizes the waste heat of two - effect rectification tower kettle wastewater to carry out preliminary preheating to raw material, forms the ladder type heat exchange network, reduces the steam consumption 20 % - 30 % simultaneously, and the steam consumption of heat pump technology further reduces 15 %, and the system is more reasonable, reduces the waste of resources, reduces the enterprise production cost. Through setting first effect rectification tower, second effect rectification tower and third effect rectification tower, make the wastewater waste heat recovery in system and make the temperature of the effluent wastewater reduce to below 40 DEG C, reduce the thermal pollution, and the steam condensate reuse rate improves to 95 %.

Description

Technical Field

[0001] This utility model relates to the field of chemical production technology, and more specifically, to a 2-thiophene ethanol distillation system. Background Technology

[0002] 2-Thiopheneethanol is a colorless or pale yellow clear liquid used as an intermediate for the antithrombotic drug ticlopidine, as well as other drug intermediates. It is also the active ingredient in 2-thiopheneethanol fragrance. With the continuous development and application of downstream products, the purity of 2-thiopheneethanol has received increasing attention.

[0003] A search revealed Chinese patent application number "202011496876.1" disclosing a 2-thiophene ethanol distillation process. This process involves: heat exchange between the feedstock and the top steam of the distillation column in a primary preheater; secondary heat exchange between the feedstock and the steam condensate in a secondary preheater; and finally, the feedstock, after secondary heat exchange, is fed into the distillation column and heated in the reboiler. The distillate from one distillation column serves as the heat source for the reboiler of the other column. A double-effect co-current operation is employed for the 2-thiophene ethanol distillation. This process yields high-purity 2-thiophene ethanol and is rationally designed.

[0004] The aforementioned 2-thiophene ethanol distillation system did not fully utilize heat, resulting in resource waste, increased production costs, and low enterprise profits.

[0005] In conclusion, there is an urgent need for a 2-thiophene ethanol distillation system to solve the above problems. Utility Model Content

[0006] To overcome the above shortcomings, this utility model provides a 2-thiophene ethanol distillation system to solve the problems of existing 2-thiophene ethanol distillation systems not making full use of heat, resulting in resource waste, increased production costs, and low enterprise profits.

[0007] This utility model is implemented as follows: After filtration to remove solid impurities ≥50μm in the pretreatment section, 2-thiophene ethanol from outside the distillation column is heated by a spiral plate primary preheater and the overhead steam of the third-effect distillation column. Next, a secondary heat exchange occurs between the preheated feedstock and the bottom wastewater of the second-effect distillation column, further raising the temperature. Subsequently, a tertiary heat exchange occurs between the preheated feedstock and the condensate from the MVR system via a spiral plate tertiary preheater, further increasing the temperature. The feedstock after these three heat exchanges is then fed into the first-effect distillation column, where saturated steam is introduced into the first-effect reboiler for vapor-liquid separation. Of the vapor phase from the top of the first-effect distillation column, 40% serves as the heat source for the second-effect reboiler (via thermosiphon circulation), and 60% enters the MVR system for recompression. The bottom liquid from the first-effect distillation column flows into the second-effect distillation column under its own pressure. The second-effect reboiler simultaneously receives the vapor phase from the top of the first-effect distillation column and the pressurized steam from the MVR system. The vapor phase from the top of the second-effect distillation column enters the spiral plate secondary preheater. 85% of the condensate is refluxed to the top of the column via thermosiphon, and 15% of the liquid phase is collected and sent to the finished product tank area (purity ≥99.5%). The bottom liquid of the second-effect distillation column is depressurized by a throttling valve and then enters the third-effect distillation column. The heat source for the third-effect reboiler of the third-effect distillation column comes from the waste heat of the MVR system to maintain the bottom temperature. The vapor phase from the top of the third-effect distillation column serves as the heat source for the spiral plate primary preheater, and after condensation, it is returned to the system. The wastewater from the bottom of the third-effect distillation column is cooled by the spiral plate primary preheater and then sent to the wastewater treatment section.

[0008] Preferably, in the MVR system integration stage, the uncondensed vapor at the top of the second-effect distillation column enters the two-stage centrifugal compressor, which supplies the second-effect reboiler as an auxiliary heat source on the one hand, and enters the spiral plate three-stage preheater to heat the raw material on the other hand, and is then condensed and recovered to the system.

[0009] Preferably, the first-effect reboiler is a bottom falling film reboiler.

[0010] The beneficial effects of this utility model compared to the prior art are: 1. The 2-thiophene ethanol distillation system shown in this utility model, by adding a three-stage preheater, utilizes the waste heat of the wastewater in the bottom of the double-effect distillation column to preheat the raw materials, forming a stepped heat exchange network; at the same time, it reduces steam consumption by 20%-30%, and the heat pump technology further reduces steam consumption by 15%, making the system more reasonable, reducing resource waste, and lowering enterprise production costs.

[0011] 2. The 2-thiophene ethanol distillation system shown in this utility model, by setting up a first-effect distillation column, a second-effect distillation column and a third-effect distillation column, enables the wastewater waste heat recovery in the system to reduce the temperature of the discharged wastewater to below 40°C, thereby reducing thermal pollution; the steam condensate reuse rate is increased to 95%.

[0012] 3. The 2-thiophene ethanol distillation system shown in this utility model, by adding a filter before preheating, achieves a purity of over 99.5% for the distilled 2-thiophene ethanol, thereby improving both product purity and system stability, and meeting the requirements of green chemical industry and low-carbon production. Attached Figure Description

[0013] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 This is a process flow diagram of the 2-thiophene ethanol distillation system of this utility model.

[0015] In the diagram: 1. 2-Thiopheneethanol (external boundary); 2. Filter; 3. Spiral plate primary preheater; 4. Spiral plate secondary preheater; 5. Spiral plate tertiary preheater; 6. MVR system; 7. First-effect distillation column; 8. First-effect reboiler; 9. Second-effect reboiler; 10. Second-effect distillation column; 11. Third-effect distillation column; 12. Third-effect reboiler; 13. Finished product tank; 14. Throttling valve. Detailed Implementation

[0016] First, it should be noted that in different described embodiments, the same components are given the same reference numerals or the same component names. The disclosure contained throughout this specification can be applied semantically to the same components having the same reference numerals or the same component names. The location descriptions selected in the specification, such as upper, lower, lateral, etc., also refer to the directly described and illustrated figures and are semantically applied to the new location when the location changes. Example 1

[0017] Please see Figure 1 This utility model provides a technical solution: Thiophene ethanol distillation system, such as Figure 1 As shown, Raw material processing: In the pretreatment section, 2-thiophene ethanol 1 is filtered by filter 2 to remove solid impurities with a particle size ≥50μm. Then, it undergoes heat exchange between the 25℃ raw material and the top steam of the 68℃ third-effect distillation column 11 via a spiral plate primary preheater 3, raising its temperature to 55℃. Next, the raw material undergoes secondary heat exchange between the primary preheated raw material and the bottom wastewater of the second-effect distillation column 10 (temperature reduced from 90℃ to 60℃) via a spiral plate secondary preheater 4, raising its temperature to 75℃. Finally, the raw material undergoes tertiary heat exchange between the secondary preheated raw material and the condensate generated by the MVR system 6 (temperature reduced from 95℃ to 80℃) via a spiral plate tertiary preheater 5, raising its temperature to 85℃.

[0018] Distillation stage: The feedstock after three heat exchanges is fed into the first-effect distillation column 7, where it is heated to 120°C using 0.3MPa saturated steam introduced into the first-effect reboiler 8 for vapor-liquid separation. Of the 105°C vapor phase at the top of the first-effect distillation column 7, 40% serves as the heat source for the second-effect reboiler 9 (via thermosiphon circulation), and 60% enters the MVR vapor recompression system 6. The 118°C liquid at the bottom of the first-effect distillation column 7 flows into the second-effect distillation column 10 under its own pressure. The second-effect reboiler 9 simultaneously receives 40% of the 105°C vapor phase from the top of the first-effect distillation column 7 and the 95°C pressurized steam from the MVR system 6. The vapor phase at 82°C at the top of the second-effect distillation column 10 enters the spiral plate secondary preheater 4. 85% of the condensate is refluxed to the top of the column via thermosiphon, and 15% of the liquid phase is collected and sent to the finished product tank 13 (purity ≥99.5%). The bottom liquid of the second-effect distillation column 10 at 90°C enters the third-effect distillation column 11 after being depressurized by the throttle valve 14. The reboiler 12 of the third-effect distillation column 11 is heated by the waste heat at 75°C from the MVR system 6, maintaining the bottom temperature at 65°C. The vapor phase at 68°C at the top of the third-effect distillation column 11 is used as the heat source for the primary preheater 3, and is returned to the system after condensation. The wastewater from the bottom of the third-effect distillation column at 60°C is cooled to 40°C by the spiral plate primary preheater 3 and then sent to the wastewater treatment section.

[0019] MVR system (6) integration link: The uncondensed steam at 65°C and 0.08MPa at the top of the second-effect distillation column 10 enters the two-stage centrifugal compressor. The first stage compressor heats the steam to 80°C (pressure 0.12MPa) and cools it to 75°C using the feed from the first effect at 85°C for intermediate cooling. The second stage compressor heats the steam to 95°C (pressure 0.15MPa). After the steam is compressed to 95°C, 70% is supplied to the second-effect reboiler 9 as an auxiliary heat source, and 30% enters the spiral plate three-stage preheater 5 to heat the raw material. After condensation, it is recovered to the system.

[0020] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A 2-thiophene ethanol distillation system, characterized in that, After solid impurities are removed by filtration using filter (2) in the pretreatment section, the raw material (1) is heated by heat exchange with the top steam of the third-effect distillation column (11) through a spiral plate primary preheater (3) and the bottom steam of the third-effect distillation column (10). The temperature is then raised by heat exchange with the raw material after primary preheating through a spiral plate secondary preheater (4) and the bottom wastewater of the second-effect distillation column (10). Finally, the raw material after secondary preheating undergoes a tertiary heat exchange with the condensate generated by the spiral plate tertiary preheater (5) and the MVR system (6). Further rise; the raw material after three heat exchanges is transported to the first-effect distillation column (7), and saturated steam is introduced into the first-effect reboiler (8) to heat the raw material for vapor-liquid separation; 40% of the gas phase at the top of the first-effect distillation column (7) is used as the heat source for the second-effect reboiler (9), and 60% enters the MVR system (6). The steam is recompressed, and the liquid at the bottom of the first-effect distillation column (7) flows into the second-effect distillation column (10) by self-pressure; the second-effect reboiler (9) simultaneously receives the gas phase at the top of the first-effect distillation column (7) and the pressurized steam from the MVR system (6); The vapor phase at the top of the second-effect distillation column (10) enters the spiral plate secondary preheater (4). 85% of the condensate is returned to the top of the column by thermosiphon, and 15% of the liquid phase is collected to the finished product tank (13). The liquid at the bottom of the second-effect distillation column (10) is depressurized by the throttle valve (14) and then enters the third-effect distillation column (11). The heat source of the third-effect reboiler (12) of the third-effect distillation column (11) comes from the residual heat of the MVR system (6) to maintain the bottom temperature. The vapor phase at the top of the third-effect distillation column (11) serves as the heat source of the spiral plate primary preheater (3). After condensation, it returns to the system. The wastewater at the bottom of the third-effect distillation column (11) is cooled by the spiral plate primary preheater (3) and then sent to the wastewater treatment section.

2. The 2-thiophene ethanol distillation system according to claim 1, characterized in that, In the MVR system (6) integration stage, the uncondensed vapor at the top of the second-effect distillation column (10) enters the two-stage centrifugal compressor and is supplied to the second-effect reboiler (9) as an auxiliary heat source. On the other hand, it enters the spiral plate three-stage preheater (5) to heat the raw material and is then condensed and recovered to the system.

3. The 2-thiophene ethanol distillation system according to claim 2, characterized in that, The first-effect reboiler (8) is a bottom falling film reboiler.

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