Tert-butyl alcohol double-effect rectification system
By adopting the dual-towel joint operation of the tert-butanol double-effect rectification system and vacuum condensation and recovery technology during the caprolactam production process, the problems of large steam consumption, cyclohexanone oxime hydrolysis and ammonia incondensation are solved, and efficient and energy-saving tert-butanol separation and quality assurance of oxime aqueous solution are achieved.
Patent Information
- Application Number
- CN202421913168.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-08-07
AI Technical Summary
Prior Art In the production process of caprolactam, the separation of tert-butanol and aqueous oxime solution requires a large amount of steam consumption, resulting in waste of steam; at the same time, the aqueous oxime solution stays in a high temperature state, resulting in hydrolysis of cyclohexanone oxime; and ammonia does not condense during the separation process, resulting in high column pressure.
The tert-butanol dual-effect distillation system is adopted, and the dual-towel of the high-pressure recovery tower is combined with the dual-tower recovery tower, and the distillation technology is used for production. The top tower gas phase of the high-pressure recovery tower is used as the reboiler heat source of the normal-pressure recovery tower. The reboiler of the high-pressure recovery tower uses steam as the heat source to reuse the non-condensed steam twice to reduce steam consumption; at the same time, the non-condensed gas containing ammonia is recovered through vacuum condensation, reducing system pressure and ammonia consumption.
It effectively reduces steam consumption, improves the treatment efficiency of tert-butanol, shortens the residence time of the oxime aqueous solution in high temperature state, avoids cyclohexanone oxime hydrolysis, ensures the quality of the oxime aqueous solution, and reduces the consumption of ammonia.
Smart Images
Figure CN222900241U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of caprolactam production, and particularly relates to a double-effect rectification system for tert-butanol. Background Art
[0002] The technological process of producing caprolactam by the ammoximation method includes an ammoximation unit, a membrane separation unit, a catalyst unloading unit, a solvent recovery unit, a toluene extraction unit, a toluene / oxime fractionation unit, a toluene separation unit, a sewage treatment unit, etc. After membrane separation, the produced cyclohexanone oxime enters the solvent recovery unit along with the tert-butanol aqueous solution, and the tert-butanol is separated by distillation and refluxed into the reactor.
[0003] In the process of recovering tert-butanol in the solvent recovery unit, a single-line single-column production process is adopted. The tert-butanol recovery column uses a once-through reboiler, and the reboiler operates at atmospheric pressure and uses 0.4 MPa steam as the heat source. The existing technical problems are as follows: In the production process, in order to separate tert-butanol from the oxime aqueous solution, the steam consumption needs to be increased, resulting in steam waste; the oxime aqueous solution stays at a high temperature at the bottom of the column for a long time, which will cause the hydrolysis of cyclohexanone oxime to produce cyclohexanone; a large amount of ammonia is contained in the reaction clear liquid. During the separation process of tert-butanol, ammonia accumulates at the top of the column as non-condensable gas, resulting in a high pressure in the tert-butanol column. Summary of the Utility Model
[0004] The purpose of the utility model is to provide a double-effect rectification system for tert-butanol.
[0005] The utility model is implemented by the following technical solutions: The double-effect rectification system for tert-butanol includes an oxime product storage tank, an atmospheric pressure recovery tower, a high-pressure recovery tower, a reboiler, a recovery tank, a tert-butanol storage tank, a high-pressure section condenser, an ammonia absorption tower, and a high-pressure section reflux tank;
[0006] The liquid inlet of the oxime product storage tank is connected to an oxime product inlet pipe, the liquid outlet of the oxime product storage tank is connected to the liquid inlet pipeline of the atmospheric pressure recovery tower, the liquid outlet of the atmospheric pressure recovery tower is connected to the liquid inlet pipeline of the high-pressure recovery tower, the non-condensable gas outlet of the high-pressure recovery tower is connected to the heat medium inlet pipeline of the reboiler of the atmospheric pressure recovery tower, the heat medium outlet of the reboiler is connected to the inlet pipeline of the recovery tank, the outlet of the recovery tank is connected to the inlet pipeline of the high-pressure section condenser, the outlet of the high-pressure section condenser is connected to the inlet pipeline of the high-pressure section reflux tank, the gas outlet of the high-pressure section reflux tank is connected to the inlet pipeline of the ammonia absorption tower, the tert-butanol outlet of the high-pressure recovery tower is connected to the inlet pipeline of the tert-butanol storage tank, the liquid outlet of the high-pressure section reflux tank is connected to the inlet pipeline of the tert-butanol storage tank, and the liquid outlet of the high-pressure recovery tower is connected to an oxime solution outlet pipe.
[0007] Further, the gas outlet of the oxime product storage tank is connected to the inlet pipeline of the ammonia absorption tower.
[0008] Further, the tert-butanol outlet of the atmospheric pressure recovery tower is connected to the inlet pipeline of the tert-butanol storage tank, the non-condensable gas outlet of the atmospheric pressure recovery tower is connected to the inlet pipeline of the air cooler in the atmospheric pressure section, the outlet of the air cooler in the atmospheric pressure section is connected to the inlet pipeline of the condenser in the atmospheric pressure section, the outlet of the condenser in the atmospheric pressure section is connected to the inlet pipeline of the reflux drum in the atmospheric pressure section, the liquid outlet of the reflux drum in the atmospheric pressure section is connected to the inlet pipeline of the tert-butanol storage tank, and the gas outlet of the reflux drum in the atmospheric pressure section is connected to the inlet pipeline of the ammonia absorption tower.
[0009] Further, the tail gas outlet of the ammonia absorption tower is connected to the pipeline of the oxime tail gas recovery system, and the ammonia outlet of the ammonia absorption tower is connected to the inlet pipeline of the oxime reactor.
[0010] Further, a sodium hydroxide inlet pipe is communicated on the pipeline between the liquid outlet of the oxime product storage tank and the liquid inlet of the atmospheric pressure recovery tower.
[0011] Advantages of the present utility model: By adding the combined operation of a double tower of an atmospheric pressure recovery tower and a high-pressure recovery tower, and adopting distillation technology for production, the top tower gas phase of the high-pressure recovery tower is used as the heat source of the reboiler of the atmospheric pressure recovery tower, and the reboiler of the high-pressure recovery tower uses steam as the heat source. Since the temperature of the non-condensable gas at the top of the high-pressure recovery tower is relatively high, this part of the steam is recycled for the second time, saving a large amount of steam consumption;
[0012] The double tower simultaneously processes tert-butanol, improving the working efficiency and solving the working cycle in single tower processing. Therefore, the residence time of the cyclohexanone oxime aqueous solution at the high temperature at the bottom of the tower is shortened, solving the problem of hydrolysis of cyclohexanone oxime and ensuring the quality of the cyclohexanone oxime aqueous solution;
[0013] The non-condensable gas containing ammonia is recovered through vacuum condensation. While reducing the internal pressure of the atmospheric pressure recovery tower and the high-pressure recovery tower, the ammonia in the system is recovered, reducing ammonia consumption. Description of the Drawings
[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0015] Figure 1 It is a structural schematic diagram of the utility model;
[0016] In the figure: the inlet pipe 1 of the oximation product, the oximation product storage tank 2, the atmospheric pressure recovery tower 3, the high-pressure recovery tower 4, the reboiler 5, the recovery tank 6, the high-pressure section condenser 7, the high-pressure section reflux tank 8, the ammonia absorption tower 9, the air cooler 10 in the atmospheric pressure section, the condenser 11 in the atmospheric pressure section, the reflux tank 12 in the atmospheric pressure section, the tert-butanol storage tank 13, the outlet pipe 14 of the oximation solution, the oximation tail gas recovery system 15, the oximation reactor 16, the inlet pipe 17 of sodium hydroxide. Specific embodiments
[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0018] As Figure 1 shown, the double-effect rectification system for tert-butanol includes an oximation product storage tank 2, an atmospheric pressure recovery tower 3, a high-pressure recovery tower 4, a reboiler 5, a recovery tank 6, a tert-butanol storage tank 13, a high-pressure section condenser 7, an ammonia absorption tower 9, and a high-pressure section reflux tank 8;
[0019] The inlet of the oximation product storage tank 2 is connected to the inlet pipe 1 of the oximation product, the outlet of the oximation product storage tank 2 is connected to the inlet pipeline of the atmospheric pressure recovery tower 3, the outlet of the atmospheric pressure recovery tower 3 is connected to the inlet pipeline of the high-pressure recovery tower 4, the non-condensable gas outlet of the high-pressure recovery tower 4 is connected to the hot medium inlet pipeline of the reboiler 5 of the atmospheric pressure recovery tower 3, the hot medium outlet of the reboiler 5 is connected to the inlet pipeline of the recovery tank 6, and the outlet of the recovery tank 6 is connected to the inlet pipeline of the high-pressure section condenser 7.
[0020] During use, through the combined operation of the double towers of the atmospheric pressure recovery tower 3 and the high-pressure recovery tower 4, production is carried out using distillation technology. The top tower gas phase of the high-pressure recovery tower 4 is used as the heat source for the reboiler 5 of the atmospheric pressure recovery tower 3, and the reboiler of the high-pressure recovery tower 4 uses steam as the heat source. Since the temperature of the non-condensable gas at the top of the high-pressure recovery tower 4 is relatively high, this part of the steam is recycled for a second time, saving a large amount of steam consumption. Since the two towers simultaneously process tert-butanol, the efficiency is improved, the working cycle during single-tower processing is solved, so the residence time of the cyclohexanone oxime aqueous solution at the bottom of the tower at a high temperature is shortened, the problem of cyclohexanone oxime hydrolysis is solved, and the quality of the cyclohexanone oxime aqueous solution is ensured.
[0021] The outlet of the high-pressure condenser 7 is connected to the inlet pipeline of the high-pressure reflux drum 8. The gas outlet of the high-pressure reflux drum 8 is connected to the inlet pipeline of the ammonia absorption tower 9. The non-condensable gas outlet of the atmospheric-pressure recovery tower 3 is connected to the inlet pipeline of the air cooler 10 in the atmospheric-pressure section. The outlet of the air cooler 10 in the atmospheric-pressure section is connected to the inlet pipeline of the atmospheric-pressure condenser 11. The outlet of the atmospheric-pressure condenser 11 is connected to the inlet pipeline of the atmospheric-pressure reflux drum 12. The gas outlet of the atmospheric-pressure reflux drum 12 is connected to the inlet pipeline of the ammonia absorption tower 9.
[0022] During use, the non-condensable gas containing ammonia is recovered through vacuum condensation, reducing the internal pressure of the atmospheric-pressure recovery tower 3 and the high-pressure recovery tower 4 while recovering ammonia in the system and reducing ammonia consumption.
[0023] The liquid outlet of the atmospheric-pressure reflux drum 12 is connected to the inlet pipeline of the tert-butanol storage tank 13. The tert-butanol outlet of the atmospheric-pressure recovery tower 3 is connected to the inlet pipeline of the tert-butanol storage tank 13. The liquid outlet of the high-pressure reflux drum 8 is connected to the inlet pipeline of the tert-butanol storage tank 13. The tert-butanol outlet of the high-pressure recovery tower 4 is connected to the inlet pipeline of the tert-butanol storage tank 13. The tert-butanol recovered by the atmospheric-pressure recovery tower 3 and the high-pressure recovery tower 4 is sent to the tert-butanol storage tank 13 for reuse.
[0024] The liquid outlet of the high-pressure recovery tower 4 is connected with an oximation solution outlet pipe 14, and the treated oximation solution is sent to the next process section for further treatment.
[0025] Furthermore, the gas outlet of the oximation product storage tank 2 is connected to the inlet pipeline of the ammonia absorption tower 9.
[0026] Furthermore, the tail gas outlet of the ammonia absorption tower 9 is connected to the pipeline of the oximation tail gas recovery system 15. The ammonia outlet of the ammonia absorption tower 9 is connected to the inlet pipeline of the oximation reactor 16. Ammonia is reused in the oximation reactor 16, and part of the non-recoverable tail gas is sent to the oximation tail gas recovery system 15 for treatment.
[0027] Furthermore, a sodium hydroxide inlet pipe 17 is connected to the pipeline between the liquid outlet of the oximation product storage tank 2 and the liquid inlet of the atmospheric-pressure recovery tower 3 to decompose the ammonium salt in the oximation reaction product with sodium hydroxide.
[0028] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
Claims
1. A tert-butyl alcohol double-effect distillation system, characterized in that: It includes an oximation product storage tank, a normal pressure recovery tower, a high pressure recovery tower, a reboiler, a recovery tank, a tert-butyl alcohol storage tank, a high pressure section condenser, an ammonia absorption tower, and a high pressure section reflux tank; The liquid inlet of the oximation product storage tank is connected to the oximation product liquid inlet pipe, the liquid outlet of the oximation product storage tank is connected to the liquid inlet pipeline of the atmospheric pressure recovery tower, the liquid outlet of the atmospheric pressure recovery tower is connected to the liquid inlet pipeline of the high-pressure recovery tower, the non-condensable gas outlet of the high-pressure recovery tower is connected to the heat medium inlet pipeline of the reboiler of the atmospheric pressure recovery tower, the heat medium outlet of the reboiler is connected to the inlet pipeline of the recovery tank, the outlet of the recovery tank is connected to the inlet pipeline of the high-pressure section condenser, the outlet of the high-pressure section condenser is connected to the inlet pipeline of the high-pressure section reflux tank, the gas outlet of the high-pressure section reflux tank is connected to the inlet pipeline of the ammonia absorption tower, the tert-butyl alcohol outlet of the high-pressure recovery tower is connected to the inlet pipeline of the tert-butyl alcohol storage tank, the liquid outlet of the high-pressure section reflux tank is connected to the inlet pipeline of the tert-butyl alcohol storage tank, and the liquid outlet of the high-pressure recovery tower is connected with the oximation solution liquid outlet pipe.
2. The tert-butyl alcohol double-effect distillation system according to claim 1, characterized in that: The gas outlet of the oximation product storage tank is connected to the inlet pipeline of the ammonia absorption tower.
3. The tert-butyl alcohol double-effect distillation system according to claim 2, characterized in that: The tert-butanol outlet of the atmospheric pressure recovery tower is connected to the inlet pipeline of the tert-butanol storage tank, the non-condensable gas outlet of the atmospheric pressure recovery tower is connected to the inlet pipeline of the atmospheric pressure section air cooler, the outlet of the atmospheric pressure section air cooler is connected to the inlet pipeline of the atmospheric pressure section condenser, the outlet of the atmospheric pressure section condenser is connected to the inlet pipeline of the atmospheric pressure section reflux tank, the liquid outlet of the atmospheric pressure section reflux tank is connected to the inlet pipeline of the tert-butanol storage tank, and the gas outlet of the atmospheric pressure section reflux tank is connected to the inlet pipeline of the ammonia absorption tower.
4. The tert-butyl alcohol double-effect distillation system according to claim 3, characterized in that: The tail gas outlet of the ammonia absorption tower is connected to the pipeline of the oximation tail gas recovery system, and the ammonia outlet of the ammonia absorption tower is connected to the inlet pipeline of the oximation reactor.
5. The tert-butyl alcohol double-effect distillation system according to claim 4, characterized in that: A sodium hydroxide liquid inlet pipe is connected to the pipeline between the liquid outlet of the oximation product storage tank and the liquid inlet of the atmospheric pressure recovery tower.