CN107434757B - Method and device for recycling caprolactam organic extractant with ultralow energy consumption - Google Patents
Method and device for recycling caprolactam organic extractant with ultralow energy consumption Download PDFInfo
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- CN107434757B CN107434757B CN201610352663.9A CN201610352663A CN107434757B CN 107434757 B CN107434757 B CN 107434757B CN 201610352663 A CN201610352663 A CN 201610352663A CN 107434757 B CN107434757 B CN 107434757B
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- C07C7/04—Purification; Separation; Use of additives by distillation
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- C07C7/04—Purification; Separation; Use of additives by distillation
- C07C7/05—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds
- C07C7/06—Purification; Separation; Use of additives by distillation with the aid of auxiliary compounds by azeotropic distillation
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- C07D223/06—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract
The invention discloses a method and a device for recycling caprolactam organic extractant with ultralow energy consumption, wherein the device comprises a high-pressure wastewater stripping tower, a medium-pressure organic solvent rectifying tower, a low-pressure organic solvent rectifying tower, a wastewater feeding preheater, an organic solvent feeding preheater, a low-pressure tower top condenser, a high-pressure tower kettle reboiler, a medium-pressure tower kettle reboiler, a low-pressure tower kettle reboiler, a split-phase tank, an organic solvent discharging cooler, a high-pressure tower top auxiliary condenser, a pump and the like; the organic extractant is recovered by double-effect rectification, and the condensation load of the top of the middle-pressure organic solvent rectifying tower is matched with the thermal load of a reboiler of the bottom of the low-pressure organic solvent rectifying tower, so that thermal coupling rectification is realized; the top steam of the high-pressure wastewater stripping tower is used for heating a tower kettle reboiler of the middle-pressure organic solvent rectifying tower, so that the ultralow energy consumption recovery of the caprolactam organic extractant is realized; greatly reduces the production cost of caprolactam.
Description
Technical Field
The invention belongs to the technical field of rectification, and particularly relates to a method and a device for recycling caprolactam organic extractant with ultralow energy consumption.
Background
In the lactam device, the cyclohexanone oxime preparation working section, the wastewater generated after the reaction solution is extracted and washed by the solvent recovery, extraction and washing of the cyclohexanone oxime aqueous solution after the reaction solvent recovery enters a wastewater stripping tower, the wastewater meeting the requirements is obtained at the bottom of the stripping tower and then is sent to a wastewater treatment station, the top discharge is separated into an organic phase after phase separation, the water phase is refluxed to the feed for continuous distillation, and the wastewater stripping tower has high energy consumption due to large water quantity and circulation quantity, different indexes of wastewater at the bottom of the tower and different consumed raw steam quantities.
In the crude caprolactam refining section, an organic extractant is required to extract caprolactam for purifying caprolactam, and then the caprolactam in the organic extractant is back-extracted by water. During the extraction process, the organic extractant must be regenerated due to the accumulation of byproducts in the organic extractant. At present, the regeneration of the organic extractant adopts a distillation method, the organic extractant is distilled out from the top of the tower to be purified, and single-tower distillation is adopted in most China, so that the energy consumption is high, and the production cost of caprolactam is increased.
If the consumption of the condensing load at the top of the tower and the heating load at the bottom of the tower can be minimized through various means, the energy saving and consumption reduction in the production process can be realized, the production cost can be reduced, the competitive advantage of the caprolactam production process can be improved, and the method has great significance.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a device for recycling caprolactam organic extractant with ultralow energy consumption.
It is a second object of the present invention to provide a second ultra low energy recovery apparatus for caprolactam organic extractant.
The third object of the invention is to provide a method for recovering caprolactam organic extractant with ultra-low energy consumption.
The technical scheme of the invention is summarized as follows:
an ultralow energy consumption caprolactam organic extractant recovery device comprises a high-pressure wastewater stripping tower 1, a medium-pressure organic solvent rectifying tower 2, a low-pressure organic solvent rectifying tower 3, a wastewater feeding preheater 4, an organic solvent feeding preheater 5, a low-pressure tower top condenser 6, a high-pressure tower kettle reboiler 7, a medium-pressure tower kettle reboiler 8, a low-pressure tower kettle reboiler 9, a phase separation tank 10, an organic solvent discharging cooler 11, a high-pressure tower top auxiliary condenser 12 and a first pump 14; the waste water feeding tank area A is sequentially connected with the waste water feeding preheater 4 and the upper part of the high-pressure waste water stripping tower 1 through pipelines, the top of the high-pressure waste water stripping tower 1 is connected with the high-pressure tower top auxiliary condenser 12 through pipelines and then divided into two paths, one path is connected with the medium-pressure tower kettle reboiler 8 and then connected with the split-phase tank 10, and the other path is directly connected with the split-phase tank 10; the upper part of the phase-splitting tank 10 is connected with a waste water organic solvent tank area I through a pipeline; the lower part of the split-phase tank 10 is connected with the upper part of the high-pressure wastewater stripping tower 1 after being connected with the first pump 14 through a pipeline; the bottom of the high-pressure wastewater stripping tower 1 is respectively connected with the bottom of a high-pressure tower kettle reboiler 7 and the shell side inlet of the wastewater feeding preheater 4 through pipelines; the top of the high-pressure tower kettle reboiler 7 is connected with the lower part of the high-pressure wastewater stripping tower 1 through a pipeline; the shell side outlet of the wastewater feeding preheater 4 is connected with a wastewater treatment working section G through a pipeline; the organic solvent feeding tank area C is connected with the organic solvent feeding preheater 5 through a pipeline and then divided into two paths, one path is connected with the upper part of the medium-pressure organic solvent rectifying tower 2, the other path is connected with the upper part of the low-pressure organic solvent rectifying tower 3, and the top of the medium-pressure organic solvent rectifying tower 2 is connected with the low-pressure tower kettle reboiler 9 and the organic solvent discharging cooler 11 in sequence through pipelines and then connected with the organic solvent tank area L; the bottom of the medium-pressure organic solvent rectifying tower 2 is respectively connected with the bottom of a reboiler 8 of the medium-pressure tower kettle and the middle part of the low-pressure organic solvent rectifying tower 3 through pipelines; the top of the middle pressure tower kettle reboiler 8 is connected with the lower part of the middle pressure organic solvent rectifying tower 2 through a pipeline; the top of the low-pressure organic solvent rectifying tower 3 is connected with a shell side inlet of the organic solvent feeding preheater 5 through a pipeline; the shell side vapor phase outlet of the organic solvent feeding preheater 5 is connected with the shell side inlet of the low-pressure tower top condenser 6 through a pipeline, and the shell side liquid phase outlet of the organic solvent feeding preheater 5 is connected with the organic solvent tank area L through a pipeline; the shell side outlet of the low-pressure tower top condenser 6 is connected with the organic solvent tank area L through a pipeline; the bottom of the low-pressure organic solvent rectifying tower 3 is respectively connected with the bottom of a low-pressure tower kettle reboiler 9 and the organic solvent heavy component separation device K through a pipeline, and the top of the low-pressure tower kettle reboiler 9 is connected with the lower part of the low-pressure organic solvent rectifying tower 3 through a pipeline; the shell side inlet of the organic solvent discharging cooler 11 is connected with a caprolactam water solution tank area D through a pipeline; the shell side outlet of the organic solvent discharging cooler 11 is connected with a caprolactam refining section M through a pipeline; the raw steam tank area B is respectively connected with a shell side inlet of the high-pressure tower kettle reboiler 7 and a shell side inlet of the medium-pressure tower kettle reboiler 8 through pipelines, and a shell side outlet of the high-pressure tower kettle reboiler 7 and a shell side outlet of the medium-pressure tower kettle reboiler 8 are respectively connected with the raw steam condensate tank area H through pipelines; the circulating cooling water tank area E is connected with the tube side of the low-pressure tower top condenser 6 through a pipeline and then is connected with the circulating water backwater tank area F.
The second device for recovering caprolactam organic extractant with ultralow energy consumption comprises a high-pressure wastewater stripping tower 21, a medium-pressure organic solvent rectifying tower 22, a low-pressure organic solvent rectifying tower 23, a wastewater feeding preheater 24, an organic solvent feeding preheater 25, a low-pressure tower top condenser 26, a high-pressure tower kettle reboiler 27, a medium-pressure tower kettle reboiler 28, a low-pressure tower kettle reboiler 29, a phase separation tank 30, an organic solvent discharging cooler 31, a high-pressure tower top auxiliary condenser 32, a first pump 34 and a second pump 33; the waste water feeding tank area A2 is sequentially connected with the waste water feeding preheater 24 and the upper part of the high-pressure waste water stripping tower 21 through pipelines, and the top of the high-pressure waste water stripping tower 21 is sequentially connected with the high-pressure tower top auxiliary condenser 32, the medium-pressure tower kettle reboiler 28 and the split-phase tank 30 through pipelines; the upper part of the phase-splitting tank 30 is connected with a waste water organic solvent tank area I2 through a pipeline; the lower part of the split-phase tank 30 is connected with the first pump 34 through a pipeline and then is connected with the upper part of the high-pressure wastewater stripping tower 21; the bottom of the high-pressure wastewater stripping tower 21 is respectively connected with the bottom of a high-pressure tower kettle reboiler 27 and the shell side inlet of the wastewater feed preheater 24 through pipelines; the top of the high-pressure tower kettle reboiler 27 is connected with the lower part of the high-pressure wastewater stripping tower 21 through a pipeline; the shell side outlet of the wastewater feed preheater 24 is connected with the wastewater treatment working section G2 through a pipeline; the organic solvent feeding tank area C2 is connected with the organic solvent feeding preheater 25 through a pipeline and then divided into two paths, one path is connected with the upper part of the medium-pressure organic solvent rectifying tower 22, the other path is connected with the upper part of the low-pressure organic solvent rectifying tower 23, and the top of the medium-pressure organic solvent rectifying tower 22 is connected with the low-pressure tower kettle reboiler 29 and the organic solvent discharging cooler 31 in sequence through pipelines and then connected with the organic solvent tank area L2; the bottom of the medium-pressure organic solvent rectifying tower 22 is respectively connected with the bottom of a medium-pressure tower kettle reboiler 28 and an organic solvent heavy component separation device K2 through pipelines; the top of the middle pressure tower kettle reboiler 28 is connected with the lower part of the middle pressure organic solvent rectifying tower 22 through a pipeline; the top of the low-pressure organic solvent rectifying tower 23 is connected with a shell side inlet of an organic solvent feeding preheater 25 through a pipeline; the shell side vapor phase outlet of the organic solvent feed preheater 25 is connected with the shell side inlet of the low pressure overhead condenser 26 through a pipeline, and the shell side liquid phase outlet of the organic solvent feed preheater 25 is connected with the organic solvent tank zone L2 through a pipeline; the shell side outlet of the low pressure overhead condenser 26 is connected to the organic solvent tank farm L2 by a pipe; the bottom of the low-pressure organic solvent rectifying tower 23 is respectively connected with the bottom of the low-pressure tower kettle reboiler 29 and the second pump 33 through a pipeline, the second pump 33 is connected with the middle part of the medium-pressure organic solvent rectifying tower 22 through a pipeline, and the top of the low-pressure tower kettle reboiler 29 is connected with the lower part of the low-pressure organic solvent rectifying tower 23 through a pipeline; the shell side inlet of the organic solvent discharging cooler 31 is connected with a caprolactam water solution tank area D2 through a pipeline; the shell side outlet of the organic solvent discharging cooler 31 is connected with a caprolactam refining section M2 through a pipeline; the raw steam tank area B2 is respectively connected with a shell side inlet of a high-pressure tower kettle reboiler 27, a shell side inlet of a medium-pressure tower kettle reboiler 28 and a split-phase tank 30 through pipelines; the shell side outlet of the high-pressure tower kettle reboiler 27 and the shell side outlet of the medium-pressure tower kettle reboiler 28 are respectively connected with a raw steam condensate tank area H2 through pipelines; the circulating cooling water tank area E2 is connected with the tube side of the low-pressure tower top condenser 26 through a pipeline and then is connected with the circulating water backwater tank area F2.
A method for recycling caprolactam organic extractant with ultra-low energy consumption, which comprises the following steps:
a) Use of the device of claim 1 or 2;
b) The operating pressure of the high-pressure wastewater stripping tower is controlled to be 0.1-1.0 MPaA, the operating pressure of the medium-pressure organic solvent rectifying tower is controlled to be 0.01-0.8 MPaA, the operating pressure of the low-pressure organic solvent rectifying tower is controlled to be 0.01-0.5 MPaA, and the top steam temperature of the high-pressure wastewater stripping tower is 5-50 ℃ higher than the bottom liquid temperature of the medium-pressure organic solvent rectifying tower; the temperature of the steam at the top of the medium-pressure organic solvent rectifying tower is 5-50 ℃ higher than that of the kettle liquid at the kettle of the low-pressure organic solvent rectifying tower;
c) The top steam of the high-pressure wastewater stripping tower provides a heat source for the medium-pressure organic solvent rectifying tower;
d) The top steam of the medium-pressure organic solvent rectifying tower provides a heat source for the low-pressure organic solvent rectifying tower;
e) And (3) carrying out heat exchange on the wastewater feed of the high-pressure wastewater stripping tower and the discharge of the high-pressure wastewater stripping tower kettle, carrying out heat exchange on the organic solvent and the top steam of the low-pressure organic solvent rectifying tower, and carrying out heat exchange on the top steam condensate of the medium-pressure organic solvent rectifying tower and the caprolactam water solution.
The invention has the advantages that:
1. the organic extractant is recovered by double-effect rectification, and the condensation load of the top of the middle-pressure organic solvent rectifying tower is matched with the thermal load of a reboiler of the bottom of the low-pressure organic solvent rectifying tower, so that the thermal coupling rectification is realized.
2. The top steam of the high-pressure wastewater stripping tower is used for heating a tower kettle reboiler of the middle-pressure organic solvent rectifying tower, so that the ultralow energy consumption recovery of the caprolactam organic extractant is realized.
3. The energy is fully recycled by exchanging heat between the wastewater feed and the discharge of the high-pressure wastewater stripping tower kettle, exchanging heat between the organic solvent feed and the steam at the top of the low-pressure organic solvent rectifying tower, and exchanging heat between the caprolactam aqueous solution and the discharge of the condensate at the top of the medium-pressure organic solvent rectifying tower.
Drawings
FIG. 1 is a schematic diagram of an apparatus for recovering caprolactam organic extractant with ultra-low energy consumption.
FIG. 2 is a schematic diagram of a second apparatus for ultra low energy recovery of caprolactam organic extractant.
Detailed Description
The invention will now be further described by way of specific examples with reference to the accompanying drawings, which are given by way of illustration only and not by way of limitation, and thus do not limit the scope of the invention.
An ultralow energy consumption caprolactam organic extractant recovery device (see figure 1) comprises a high-pressure wastewater stripping tower 1, a medium-pressure organic solvent rectifying tower 2, a low-pressure organic solvent rectifying tower 3, a wastewater feeding preheater 4, an organic solvent feeding preheater 5, a low-pressure tower top condenser 6, a high-pressure tower kettle reboiler 7, a medium-pressure tower kettle reboiler 8, a low-pressure tower kettle reboiler 9, a phase separation tank 10, an organic solvent discharging cooler 11, a high-pressure tower top auxiliary condenser 12 and a first pump 14; the waste water feeding tank area A is sequentially connected with the waste water feeding preheater 4 and the upper part of the high-pressure waste water stripping tower 1 through pipelines, the top of the high-pressure waste water stripping tower 1 is connected with the high-pressure tower top auxiliary condenser 12 through pipelines and then divided into two paths, one path is connected with the medium-pressure tower kettle reboiler 8 and then connected with the split-phase tank 10, and the other path is directly connected with the split-phase tank 10; the upper part of the phase-splitting tank 10 is connected with a waste water organic solvent tank area I through a pipeline; the lower part of the split-phase tank 10 is connected with the upper part of the high-pressure wastewater stripping tower 1 after being connected with the first pump 14 through a pipeline; the bottom of the high-pressure wastewater stripping tower 1 is respectively connected with the bottom of a high-pressure tower kettle reboiler 7 and the shell side inlet of the wastewater feeding preheater 4 through pipelines; the top of the high-pressure tower kettle reboiler 7 is connected with the lower part of the high-pressure wastewater stripping tower 1 through a pipeline; the shell side outlet of the wastewater feeding preheater 4 is connected with a wastewater treatment working section G through a pipeline; the organic solvent feeding tank area C is connected with the organic solvent feeding preheater 5 through a pipeline and then divided into two paths, one path is connected with the upper part of the medium-pressure organic solvent rectifying tower 2, the other path is connected with the upper part of the low-pressure organic solvent rectifying tower 3, and the top of the medium-pressure organic solvent rectifying tower 2 is connected with the low-pressure tower kettle reboiler 9 and the organic solvent discharging cooler 11 in sequence through pipelines and then connected with the organic solvent tank area L; the bottom of the medium-pressure organic solvent rectifying tower 2 is respectively connected with the bottom of a reboiler 8 of the medium-pressure tower kettle and the middle part of the low-pressure organic solvent rectifying tower 3 through pipelines; the top of the middle pressure tower kettle reboiler 8 is connected with the lower part of the middle pressure organic solvent rectifying tower 2 through a pipeline; the top of the low-pressure organic solvent rectifying tower 3 is connected with a shell side inlet of the organic solvent feeding preheater 5 through a pipeline; the shell side vapor phase outlet of the organic solvent feeding preheater 5 is connected with the shell side inlet of the low-pressure tower top condenser 6 through a pipeline, and the shell side liquid phase outlet of the organic solvent feeding preheater 5 is connected with the organic solvent tank area L through a pipeline; the shell side outlet of the low-pressure tower top condenser 6 is connected with the organic solvent tank area L through a pipeline; the bottom of the low-pressure organic solvent rectifying tower 3 is respectively connected with the bottom of a low-pressure tower kettle reboiler 9 and the organic solvent heavy component separation device K through a pipeline, and the top of the low-pressure tower kettle reboiler 9 is connected with the lower part of the low-pressure organic solvent rectifying tower 3 through a pipeline; the shell side inlet of the organic solvent discharging cooler 11 is connected with a caprolactam water solution tank area D through a pipeline; the shell side outlet of the organic solvent discharging cooler 11 is connected with a caprolactam refining section M through a pipeline; the raw steam tank area B is respectively connected with a shell side inlet of the high-pressure tower kettle reboiler 7 and a shell side inlet of the medium-pressure tower kettle reboiler 8 through pipelines, and a shell side outlet of the high-pressure tower kettle reboiler 7 and a shell side outlet of the medium-pressure tower kettle reboiler 8 are respectively connected with the raw steam condensate tank area H through pipelines; the circulating cooling water tank area E is connected with the tube side of the low-pressure tower top condenser 6 through a pipeline and then is connected with the circulating water backwater tank area F.
The second device for recovering caprolactam organic extractant with ultralow energy consumption (see fig. 2) comprises a high-pressure wastewater stripper 21, a medium-pressure organic solvent rectifying tower 22, a low-pressure organic solvent rectifying tower 23, a wastewater feeding preheater 24, an organic solvent feeding preheater 25, a low-pressure tower top condenser 26, a high-pressure tower kettle reboiler 27, a medium-pressure tower kettle reboiler 28, a low-pressure tower kettle reboiler 29, a phase separation tank 30, an organic solvent discharging cooler 31, a high-pressure tower top auxiliary condenser 32, a first pump 34 and a second pump 33; the waste water feeding tank area A2 is sequentially connected with the waste water feeding preheater 24 and the upper part of the high-pressure waste water stripping tower 21 through pipelines, and the top of the high-pressure waste water stripping tower 21 is sequentially connected with the high-pressure tower top auxiliary condenser 32, the medium-pressure tower kettle reboiler 28 and the split-phase tank 30 through pipelines; the upper part of the phase-splitting tank 30 is connected with a waste water organic solvent tank area I2 through a pipeline; the lower part of the split-phase tank 30 is connected with the first pump 34 through a pipeline and then is connected with the upper part of the high-pressure wastewater stripping tower 21; the bottom of the high-pressure wastewater stripping tower 21 is respectively connected with the bottom of a high-pressure tower kettle reboiler 27 and the shell side inlet of the wastewater feed preheater 24 through pipelines; the top of the high-pressure tower kettle reboiler 27 is connected with the lower part of the high-pressure wastewater stripping tower 21 through a pipeline; the shell side outlet of the wastewater feed preheater 24 is connected with the wastewater treatment working section G2 through a pipeline; the organic solvent feeding tank area C2 is connected with the organic solvent feeding preheater 25 through a pipeline and then divided into two paths, one path is connected with the upper part of the medium-pressure organic solvent rectifying tower 22, the other path is connected with the upper part of the low-pressure organic solvent rectifying tower 23, and the top of the medium-pressure organic solvent rectifying tower 22 is connected with the low-pressure tower kettle reboiler 29 and the organic solvent discharging cooler 31 in sequence through pipelines and then connected with the organic solvent tank area L2; the bottom of the medium-pressure organic solvent rectifying tower 22 is respectively connected with the bottom of a medium-pressure tower kettle reboiler 28 and an organic solvent heavy component separation device K2 through pipelines; the top of the middle pressure tower kettle reboiler 28 is connected with the lower part of the middle pressure organic solvent rectifying tower 22 through a pipeline; the top of the low-pressure organic solvent rectifying tower 23 is connected with a shell side inlet of an organic solvent feeding preheater 25 through a pipeline; the shell side vapor phase outlet of the organic solvent feed preheater 25 is connected with the shell side inlet of the low pressure overhead condenser 26 through a pipeline, and the shell side liquid phase outlet of the organic solvent feed preheater 25 is connected with the organic solvent tank zone L2 through a pipeline; the shell side outlet of the low pressure overhead condenser 26 is connected to the organic solvent tank farm L2 by a pipe; the bottom of the low-pressure organic solvent rectifying tower 23 is respectively connected with the bottom of the low-pressure tower kettle reboiler 29 and the second pump 33 through a pipeline, the second pump 33 is connected with the middle part of the medium-pressure organic solvent rectifying tower 22 through a pipeline, and the top of the low-pressure tower kettle reboiler 29 is connected with the lower part of the low-pressure organic solvent rectifying tower 23 through a pipeline; the shell side inlet of the organic solvent discharging cooler 31 is connected with a caprolactam water solution tank area D2 through a pipeline; the shell side outlet of the organic solvent discharging cooler 31 is connected with a caprolactam refining section M2 through a pipeline; the raw steam tank area B2 is respectively connected with a shell side inlet of a high-pressure tower kettle reboiler 27, a shell side inlet of a medium-pressure tower kettle reboiler 28 and a split-phase tank 30 through pipelines; the shell side outlet of the high-pressure tower kettle reboiler 27 and the shell side outlet of the medium-pressure tower kettle reboiler 28 are respectively connected with a raw steam condensate tank area H2 through pipelines; the circulating cooling water tank area E2 is connected with the tube side of the low-pressure tower top condenser 26 through a pipeline and then is connected with the circulating water backwater tank area F2.
A method for recycling caprolactam organic extractant with ultra-low energy consumption, which comprises the following steps:
a) Using the first device or the second device;
b) The operating pressure of the high-pressure wastewater stripping tower is controlled to be 0.1-1.0 MPaA, the operating pressure of the medium-pressure organic solvent rectifying tower is controlled to be 0.01-0.8 MPaA, the operating pressure of the low-pressure organic solvent rectifying tower is controlled to be 0.01-0.5 MPaA, and the top steam temperature of the high-pressure wastewater stripping tower is 5-50 ℃ higher than the bottom tower liquid temperature of the medium-pressure organic solvent rectifying tower; the temperature of the steam at the top of the medium-pressure organic solvent rectifying tower is 5-50 ℃ higher than that of the kettle liquid at the kettle of the low-pressure organic solvent rectifying tower;
c) The top steam of the high-pressure wastewater stripping tower provides a heat source for the medium-pressure organic solvent rectifying tower;
d) The top steam of the medium-pressure organic solvent rectifying tower provides a heat source for the low-pressure organic solvent rectifying tower;
e) The waste water feeding of the high-pressure waste water stripping tower exchanges heat with the discharging of the high-pressure waste water stripping tower kettle, the organic solvent feeding exchanges heat with the tower top steam of the low-pressure organic solvent rectifying tower, and the tower top steam condensate of the medium-pressure organic solvent rectifying tower exchanges heat with caprolactam water solution.
Example 1
With the first device, the operation method of the process flow A is as follows:
the waste water raw material from the waste water feeding tank area A is preheated by a waste water feeding preheater 4 and then enters a high-pressure waste water stripping tower 1 for stripping separation, the top steam of the high-pressure waste water stripping tower passes through a high-pressure tower top auxiliary condenser 12 (the condenser does not work), the high-pressure waste water stripping tower top steam is introduced into a middle-pressure tower kettle reboiler 8, the condensed waste water is introduced into a phase separation tank 10, the upper organic phase of the phase separation tank 10 is extracted into a waste water organic solvent tank area I, and the lower water phase is pressurized by a first pump 14 and then enters the high-pressure waste water stripping tower 1; the liquid phase at the tower bottom of the high-pressure wastewater stripping tower 1 is divided into two streams, one stream is evaporated by a reboiler 7 at the high-pressure tower bottom and then returned to the high-pressure wastewater stripping tower 1, and the other stream is discharged to a wastewater treatment section G after heat exchange with wastewater feed by a wastewater feed preheater 4; the organic solvent from the organic solvent feeding tank area C enters the medium-pressure organic solvent rectifying tower 2 and the low-pressure organic solvent rectifying tower 3 respectively after passing through the organic solvent feeding preheater 5, the top steam of the medium-pressure organic solvent rectifying tower 2 is used as a heat source of the low-pressure organic solvent rectifying tower 3, condensed by the low-pressure tower kettle reboiler 9, and then enters the organic solvent tank area L after passing through the organic solvent discharging cooler 11 to exchange heat with caprolactam water solution from the caprolactam water solution tank area D; introducing the caprolactam water solution subjected to heat exchange into a caprolactam refining section M; the liquid phase at the tower bottom of the medium-pressure organic solvent rectifying tower 2 is divided into two parts, one part is evaporated by a reboiler 8 at the tower bottom of the medium-pressure organic solvent rectifying tower and then returns to the medium-pressure organic solvent rectifying tower 2, and the other part enters a low-pressure organic solvent rectifying tower 3 for continuous rectification; the tower top steam of the low-pressure organic solvent rectifying tower 3 exchanges heat with the organic solvent from the organic solvent feeding tank area C through the organic solvent feeding preheater 5, and then is condensed through the low-pressure tower top condenser 6, and the condensate is conveyed to the organic solvent tank area L; the liquid phase of the tower kettle of the low-pressure organic solvent rectifying tower 3 is divided into two parts, one part is evaporated by a reboiler 9 of the low-pressure tower kettle and then returns to the low-pressure organic solvent rectifying tower 3, and the other part enters an organic solvent heavy component separating device K; the circulating cooling water from the circulating cooling water tank area E is used as a cold source of the low-pressure tower top condenser 6; after cooling, introducing circulating water into a backwater tank area F; raw steam from the raw steam tank area B is used as a heat source of a high-pressure tower kettle reboiler 7; after heat exchange, introducing a raw steam condensate tank area H; the medium-pressure organic solvent rectifying tower 2 and the low-pressure organic solvent rectifying tower 3 are fed through a pressure difference, and are not required to be fed through a pump.
For caprolactam devices producing 100kt in a certain year in Shandong province, the mass composition of the wastewater raw materials is as follows: 99.9% of water, 0.0301% of toluene, 0.0184% of cyclohexanone oxime and 0.0515% of other reaction byproducts.
The organic solvent feed tank zone C contains the following organic extractant by mass: 99.4% of benzene, 0.1% of water, 0.1% of cyclohexanone, 0.1% of cyclohexanol, 0.1% of aniline and 0.2% of other reaction byproducts.
The operation pressure of the high-pressure wastewater stripping tower is 0.24MPaA, the temperature of the top of the tower is 126 ℃, the temperature of the bottom of the tower is 126.8 ℃, and the theoretical stage number of the tower is 15; the operating pressure of the medium-pressure organic solvent rectifying tower is 0.22MPaA, the temperature of the tower top is 107.4 ℃, the temperature of the tower bottom is 109.2 ℃, and the theoretical stage number of the tower is 8; the operating pressure of the low-pressure organic solvent rectifying tower is 0.1MPaA, the temperature of the tower top is 79.6 ℃, the temperature of the tower bottom is 87.3 ℃, and the theoretical stage number of the tower is 8.
Through the process, the discharged materials of all tower bottoms at the top of the tower reach the processing requirement of the factory. Since the process allows for sufficient thermal coupling, the loading of each column is as in table 1 (the heating or cooling thermal loading saved in brackets):
TABLE 1
| Cooling load/KW | Heating load/KW | aggregate/KW | |
| High-pressure waste water stripping tower | (4217) | 4500 | 4500(8717) |
| Medium-pressure organic solvent rectifying tower | (3333) | (4011) | (7344) |
| Low-pressure organic solvent rectifying tower | 2241 | (3137) | 2241(5378) |
| Totalizing | 2241(9791) | 4500(11648) | 6741(21439) |
When the embodiment is uncoupled, the total heating load of each tower is 11648KW, the condensing load is 9791KW, and the total heating load is 21439KW; after coupling, the total heating load of each tower is 4500KW, the condensing load is 2241KW, and the total heating load is 6741KW; the heating load is saved by 61.4%, the condensing load is saved by 77.1%, and the total heat load is saved by 68.6%.
The recovery heat load of the caprolactam organic extractant in the embodiment is derived from the high-pressure wastewater stripping tower, and the condensation load of the top of the high-pressure wastewater stripping tower is matched with the recovery heat load of the caprolactam organic extractant by increasing the heating load of the high-pressure wastewater stripping tower, so that the caprolactam organic extractant is recovered with ultralow energy consumption.
Example 2
With the second device, the operation method of the process flow B is as follows:
the waste water raw material from the waste water feeding tank area A2 enters a high-pressure waste water stripping tower 21 for stripping separation after being preheated by a waste water feeding preheater 24, high-pressure waste water stripping tower top steam passes through a high-pressure tower top auxiliary condenser 32 (the condenser does not work), is introduced into a medium-pressure tower kettle reboiler 28, is condensed and then is introduced into a phase separation tank 30, an organic phase at the upper part of the phase separation tank 30 is extracted into a waste water organic solvent tank area I2, and a lower water phase enters the high-pressure waste water stripping tower 21 after being pressurized by a first pump 34; the liquid phase at the tower bottom of the high-pressure wastewater stripping tower 21 is divided into two streams, one stream is evaporated by a reboiler 27 at the high-pressure tower bottom and then returned to the high-pressure wastewater stripping tower 21, and the other stream is discharged to a wastewater treatment section G2 after heat exchange with wastewater feed by a wastewater feed preheater 24; the organic solvent from the organic solvent feeding tank area C2 enters the medium-pressure organic solvent rectifying tower 22 and the low-pressure organic solvent rectifying tower 23 respectively after passing through the organic solvent feeding preheater 5, the top steam of the medium-pressure organic solvent rectifying tower 22 is used as a heat source of the low-pressure organic solvent rectifying tower 23, condensed by the low-pressure tower kettle reboiler 29, and then enters the organic solvent tank area L2 after passing through the organic solvent discharging cooler 31 to exchange heat with caprolactam water solution from the caprolactam water solution tank area D2; introducing the caprolactam water solution subjected to heat exchange into a caprolactam refining section M2; the liquid phase at the tower bottom of the medium-pressure organic solvent rectifying tower 22 is divided into two parts, one part is evaporated by a reboiler 28 at the tower bottom of the medium-pressure organic solvent rectifying tower and then returns to the medium-pressure organic solvent rectifying tower 22, and the other part enters an organic solvent heavy component separating device K2; the tower top steam of the low-pressure organic solvent rectifying tower 23 is preheated by an organic solvent feeding preheater 25 and the organic solvent from the organic solvent feeding tank area C2, and then condensed by a low-pressure tower top condenser 26, and the condensate is fed to the organic solvent tank area L2; the liquid phase at the bottom of the low-pressure organic solvent rectifying tower 23 is divided into two parts, one part is evaporated by a reboiler 29 at the bottom of the low-pressure tower and then returns to the low-pressure organic solvent rectifying tower 23, and the other part is pressurized by a second pump 33 and then enters the medium-pressure organic solvent rectifying tower 22; the circulating cooling water from the circulating cooling water tank area E2 is used as a cold source of the low-pressure tower top condenser 26; after cooling, introducing circulating water into a backwater tank area F2; raw steam from the raw steam tank farm B2 is used as a heat source for the autoclave reboiler 27; and after heat exchange, introducing the raw steam condensate tank area H2.
For a caprolactam device producing 100kt/a in a certain year in Shandong, the composition of the wastewater raw materials is as follows: 99.9% of water, 0.0301% of toluene, 0.0184% of cyclohexanone oxime and 0.0515% of other reaction byproducts.
The organic solvent feed tank zone C contains the following organic extractant by mass: 99.4% of benzene, 0.1% of water, 0.1% of cyclohexanone, 0.1% of cyclohexanol, 0.1% of aniline and 0.2% of other reaction byproducts.
The operation pressure of the high-pressure wastewater stripping tower is 0.3MPaA, the temperature of the top of the tower is 133.6 ℃, the temperature of the bottom of the tower is 134.2 ℃, and the theoretical stage number of the tower is 15; the operating pressure of the medium-pressure organic solvent rectifying tower is 0.22MPaA, the temperature of the tower top is 103.8 ℃, the temperature of the tower bottom is 112.2 ℃, and the theoretical stage number of the tower is 8; the operating pressure of the low-pressure organic solvent rectifying tower is 0.1MPaA, the temperature of the tower top is 79.6 ℃, the temperature of the tower bottom is 87.3 ℃, and the theoretical stage number of the tower is 8.
Through the process, the discharged materials of all tower bottoms at the top of the tower reach the processing requirement of the factory. Since the process allows for sufficient thermal coupling, the loading of each column is as in table 2 (the heating or cooling thermal loading saved in brackets):
TABLE 2
| Cooling load/KW | Heating load/KW | aggregate/KW | |
| High-pressure waste water stripping tower | (4050) | 4250 | 4250(8300) |
| Medium-pressure organic solvent rectifying tower | (3397) | (3812) | (7209) |
| Low-pressure organic solvent rectifying tower | 2206 | (3211) | 2206(5417) |
| Totalizing | 2206(9653) | 4250(11473) | 6456(21126) |
When the embodiment is uncoupled, the total heating load of each tower is 11473KW, the condensing load is 9653KW, and the total heating load is 21126KW; after coupling, the total heating load of each tower is 4250KW, the condensing load is 2206KW, and the total heating load is 6456KW; the heating load is 63%, the condensing load is 77.1%, and the total heat load is 69.4%.
The recovery heat load of the caprolactam organic extractant in the embodiment is derived from the high-pressure wastewater stripping tower, and the condensation load of the top of the high-pressure wastewater stripping tower is matched with the recovery heat load of the caprolactam organic extractant by increasing the heating load of the high-pressure wastewater stripping tower, so that the caprolactam organic extractant is recovered with ultralow energy consumption.
Example 3
With the first device, the process flow a (why two a) operates as follows:
the waste water raw material from the waste water feeding tank area A is preheated by a waste water feeding preheater 4 and then enters a high-pressure waste water stripping tower 1 for stripping separation, the top steam of the high-pressure waste water stripping tower passes through a high-pressure tower top auxiliary condenser 12, condensed and then is introduced into a phase-splitting tank 10, the organic phase at the upper part of the phase-splitting tank 10 is extracted into a waste water organic solvent tank area I, and the water phase at the lower part is pressurized by a first pump 14 and then enters the high-pressure waste water stripping tower 1; the liquid phase at the tower bottom of the high-pressure wastewater stripping tower 1 is divided into two streams, one stream is evaporated by a reboiler 7 at the high-pressure tower bottom and then returned to the high-pressure wastewater stripping tower 1, and the other stream is discharged to a wastewater treatment section G after heat exchange with wastewater feed by a wastewater feed preheater 4; the organic solvent from the organic solvent feeding tank area C enters the medium-pressure organic solvent rectifying tower 2 and the low-pressure organic solvent rectifying tower 3 respectively after passing through the organic solvent feeding preheater 5, the top steam of the medium-pressure organic solvent rectifying tower 2 is used as a heat source of the low-pressure organic solvent rectifying tower 3, condensed by the low-pressure tower kettle reboiler 9, and then enters the organic solvent tank area L after passing through the organic solvent discharging cooler 11 to exchange heat with caprolactam water solution from the caprolactam water solution tank area D; introducing the caprolactam water solution subjected to heat exchange into a caprolactam refining section M; the liquid phase at the tower bottom of the medium-pressure organic solvent rectifying tower 2 is divided into two parts, one part is evaporated by a reboiler 8 at the tower bottom of the medium-pressure organic solvent rectifying tower and then returns to the medium-pressure organic solvent rectifying tower 2, and the other part enters a low-pressure organic solvent rectifying tower 3 for continuous rectification; the tower top steam of the low-pressure organic solvent rectifying tower 3 is preheated by an organic solvent feeding preheater 5 and the organic solvent from the organic solvent feeding tank area C, and then condensed by a low-pressure tower top condenser 6, and the condensate is fed to the organic solvent tank area L; the liquid phase of the tower kettle of the low-pressure organic solvent rectifying tower 3 is divided into two parts, one part is evaporated by a reboiler 9 of the low-pressure tower kettle and then returns to the low-pressure organic solvent rectifying tower 3, and the other part enters an organic solvent heavy component separating device K; the circulating cooling water from the circulating cooling water tank area E is used as a cold source of the low-pressure tower top condenser 6; after cooling, introducing circulating water into a backwater tank area F; raw steam from the raw steam tank area B is used as a heat source of a high-pressure tower kettle reboiler 7 and a medium-pressure tower kettle reboiler 8, and is introduced into the raw steam condensate tank area H after heat exchange; the medium-pressure organic solvent rectifying tower 2 and the low-pressure organic solvent rectifying tower are fed through a pressure difference, and are not required to be fed through a pump.
For caprolactam devices producing 100kt in a certain year in Shandong province, the mass composition of the wastewater raw materials is as follows: 99.9% of water, 0.0301% of toluene, 0.0184% of cyclohexanone oxime and 0.0515% of other reaction byproducts.
The organic solvent feed tank zone C contains the following organic extractant by mass: 99.4% of benzene, 0.1% of water, 0.1% of cyclohexanone, 0.1% of cyclohexanol, 0.1% of aniline and 0.2% of other reaction byproducts.
The operation pressure of the high-pressure wastewater stripping tower is 0.1MPaA, the tower top temperature is 91.5 ℃, the tower bottom temperature is 97.1 ℃, and the theoretical stage number of the tower is 15; the operating pressure of the medium-pressure organic solvent rectifying tower is 0.22MPaA, the temperature of the tower top is 107.4 ℃, the temperature of the tower bottom is 109.2 ℃, and the theoretical stage number of the tower is 8; the operating pressure of the low-pressure organic solvent rectifying tower is 0.1MPaA, the temperature of the tower top is 79.6 ℃, the temperature of the tower bottom is 87.3 ℃, and the theoretical stage number of the tower is 8.
Through the process, the discharged materials of all tower bottoms at the top of the tower reach the processing requirement of the factory. Since the process allows for sufficient thermal coupling, the loading of each column is as in table 3 (the heating or cooling thermal loading saved in brackets):
TABLE 3 Table 3
| Cooling load/KW | Heating load/KW | aggregate/KW | |
| High-pressure waste water stripping tower | 2311 | 2450 | 4761 |
| Medium-pressure organic solvent rectifying tower | (3333) | 4011 | 4011(7344) |
| Low-pressure organic solvent rectifying tower | 2241 | (3137) | 2241(5378) |
| Total of organic solvent rectifying towers | 2241(5574) | 4011(7148) | 6252(12722) |
The high-pressure wastewater stripping tower and the organic solvent rectifying tower of the embodiment are independently operated, the organic solvent rectifying tower adopts high-low pressure double-effect rectification, and when the organic solvent rectifying tower is not coupled, the total heating load of each tower is 7148KW, the condensation load is 5574KW, and the total heating load is 12722KW; after coupling, the total heating load of each tower is 4011KW, the condensing load is 2241KW, and the total heating load is 6252KW; the heating load is saved by 43.9%, the condensing load is saved by 64.2%, and the total heat load is saved by 50.9%.
The embodiment does not carry out complete coupling, only carries out double-effect coupling rectification on the organic solvent rectifying tower, obviously saves the energy consumption for recycling the organic solvent, and has the advantages of flexible operation, large degree of freedom and easy operation.
Example 4
With the second device, the operation method of the process flow B is as follows:
the waste water raw material from the waste water feeding tank area A2 enters a high-pressure waste water stripping tower 21 for stripping separation after being preheated by a waste water feeding preheater 24, the top steam of the high-pressure waste water stripping tower passes through a high-pressure tower top auxiliary condenser 32, is condensed and then is introduced into a phase-splitting tank 30, the organic phase at the upper part of the phase-splitting tank 30 is extracted into a waste water organic solvent tank area I2, and the water phase at the lower part is pressurized by a first pump 34 and then enters the high-pressure waste water stripping tower 21; the liquid phase at the tower bottom of the high-pressure wastewater stripping tower 21 is divided into two streams, one stream is evaporated by a reboiler 27 at the high-pressure tower bottom and then returned to the high-pressure wastewater stripping tower 21, and the other stream is discharged to a wastewater treatment section G2 after heat exchange with wastewater feed by a wastewater feed preheater 24; the organic solvent from the organic solvent feeding tank area C2 enters the medium-pressure organic solvent rectifying tower 22 and the low-pressure organic solvent rectifying tower 23 respectively after passing through the organic solvent feeding preheater 5, the top steam of the medium-pressure organic solvent rectifying tower 22 is used as a heat source of the low-pressure organic solvent rectifying tower 23, condensed by the low-pressure tower kettle reboiler 29, and then enters the organic solvent tank area L2 after passing through the organic solvent discharging cooler 31 to exchange heat with caprolactam water solution from the caprolactam water solution tank area D2; introducing the caprolactam water solution subjected to heat exchange into a caprolactam refining section M2; the liquid phase at the tower bottom of the medium-pressure organic solvent rectifying tower 22 is divided into two parts, one part is evaporated by a reboiler 28 at the tower bottom of the medium-pressure organic solvent rectifying tower and then returns to the medium-pressure organic solvent rectifying tower 22, and the other part enters an organic solvent heavy component separating device K2; the tower top steam of the low-pressure organic solvent rectifying tower 23 is preheated by an organic solvent feeding preheater 25 and the organic solvent from the organic solvent feeding tank area C2, and then condensed by a low-pressure tower top condenser 26, and the condensate is fed to the organic solvent tank area L2; the liquid phase at the bottom of the low-pressure organic solvent rectifying tower 23 is divided into two parts, one part is evaporated by a reboiler 29 at the bottom of the low-pressure tower and then returns to the low-pressure organic solvent rectifying tower 23, and the other part is pressurized by a second pump 33 and then enters the medium-pressure organic solvent rectifying tower 22; the circulating cooling water from the circulating cooling water tank area E2 is used as a cold source of the low-pressure tower top condenser 26; after cooling, introducing circulating water into a backwater tank area F2; raw steam from the raw steam tank area B2 is used as a heat source of a high-pressure tower kettle reboiler 27 and a medium-pressure tower kettle reboiler 28, and is introduced into the raw steam condensate tank area H2 after heat exchange.
For a caprolactam device producing 100kt/a in a certain year in Shandong, the composition of the wastewater raw materials is as follows: 99.9% of water, 0.0301% of toluene, 0.0184% of cyclohexanone oxime and 0.0515% of other reaction byproducts.
The organic solvent feed tank zone C contains the following organic extractant by mass: 99.4% of benzene, 0.1% of water, 0.1% of cyclohexanone, 0.1% of cyclohexanol, 0.1% of aniline and 0.2% of other reaction byproducts.
The operation pressure of the high-pressure wastewater stripping tower is 0.1MPaA, the tower top temperature is 91.5 ℃, the tower bottom temperature is 97.1 ℃, and the theoretical stage number of the tower is 15; the operating pressure of the medium-pressure organic solvent rectifying tower is 0.22MPaA, the temperature of the tower top is 103.8 ℃, the temperature of the tower bottom is 112.2 ℃, and the theoretical stage number of the tower is 8; the operating pressure of the low-pressure organic solvent rectifying tower is 0.1MPaA, the temperature of the tower top is 79.6 ℃, the temperature of the tower bottom is 87.3 ℃, and the theoretical stage number of the tower is 8.
Through the process, the discharged materials of all tower bottoms at the top of the tower reach the processing requirement of the factory. Since the process allows for sufficient thermal coupling, the loading of each column is as in table 4 (the heating or cooling thermal loading saved in brackets):
TABLE 4 Table 4
| Cooling load/KW | Heating load/KW | aggregate/KW | |
| High-pressure waste water stripping tower | 2325 | 2477 | 4802 |
| Medium-pressure organic solvent rectifying tower | (3397) | 3812 | 3812(7209) |
| Low-pressure organic solvent rectifying tower | 2206 | (3211) | 2206(5407) |
| Totalizing | 2206(5603) | 3812(7023) | 6018(12616) |
The high-pressure wastewater stripping tower and the organic solvent rectifying tower of the embodiment independently operate, the organic solvent rectifying tower adopts high-low pressure double-effect rectification, and when the organic solvent rectifying tower is not coupled, the total heating load of each tower is 7023KW, the condensation load is 5603KW, and the total heat load is 12616KW; after coupling, the total heating load of each tower is 3812KW, the condensing load is 2206KW, and the total heating load is 6018KW; the heating load is saved by 45.7%, the condensing load is saved by 60.6%, and the total heat load is saved by 52.3%.
The embodiment does not carry out complete coupling, only carries out double-effect coupling rectification on the organic solvent rectifying tower, obviously saves the energy consumption for recycling the organic solvent, and has the advantages of flexible operation, large degree of freedom and easy operation.
While the present invention has been described with respect to the preferred embodiments, it will be apparent to those skilled in the art that the present invention may be practiced with modification and appropriate combination of the method and apparatus described herein without departing from the spirit, scope, or spirit of the invention. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and content of the invention.
Claims (3)
1. An ultralow energy consumption caprolactam organic extractant recovery device comprises a high-pressure wastewater stripping tower (1), a medium-pressure organic solvent rectifying tower (2), a low-pressure organic solvent rectifying tower (3), a wastewater feeding preheater (4), an organic solvent feeding preheater (5), a low-pressure tower top condenser (6), a high-pressure tower kettle reboiler (7), a medium-pressure tower kettle reboiler (8), a low-pressure tower kettle reboiler (9), a phase separation tank (10), an organic solvent discharging cooler (11), a high-pressure tower top auxiliary condenser (12) and a first pump (14); the method is characterized in that: the waste water feeding tank area (A) is sequentially connected with the waste water feeding preheater (4) and the upper part of the high-pressure waste water stripping tower (1) through pipelines, the top of the high-pressure waste water stripping tower (1) is connected with the high-pressure tower top auxiliary condenser (12) through pipelines and then divided into two paths, one path is connected with the medium-pressure tower kettle reboiler (8) and then connected with the phase-splitting tank (10), and the other path is directly connected with the phase-splitting tank (10); the upper part of the phase-splitting tank (10) is connected with a waste water organic solvent tank area (I) through a pipeline; the lower part of the split-phase tank (10) is connected with the upper part of the high-pressure wastewater stripping tower (1) after being connected with the first pump (14) through a pipeline; the bottom of the high-pressure wastewater stripping tower (1) is respectively connected with the bottom of a high-pressure tower kettle reboiler (7) and a shell side inlet of the wastewater feeding preheater (4) through pipelines; the top of the high-pressure tower kettle reboiler (7) is connected with the lower part of the high-pressure wastewater stripping tower (1) through a pipeline; the shell side outlet of the wastewater feeding preheater (4) is connected with a wastewater treatment working section (G) through a pipeline; the organic solvent feeding tank area (C) is connected with the organic solvent feeding preheater (5) through a pipeline and then divided into two paths, one path is connected with the upper part of the medium-pressure organic solvent rectifying tower (2), the other path is connected with the upper part of the low-pressure organic solvent rectifying tower (3), and the top of the medium-pressure organic solvent rectifying tower (2) is sequentially connected with the low-pressure tower kettle reboiler (9) and the organic solvent discharging cooler (11) through pipelines and then is connected with the organic solvent tank area (L); the bottom of the medium-pressure organic solvent rectifying tower (2) is respectively connected with the bottom of a reboiler (8) of the medium-pressure tower and the middle of the low-pressure organic solvent rectifying tower (3) through pipelines; the top of the middle pressure tower kettle reboiler (8) is connected with the lower part of the middle pressure organic solvent rectifying tower (2) through a pipeline; the top of the low-pressure organic solvent rectifying tower (3) is connected with a shell side inlet of an organic solvent feeding preheater (5) through a pipeline; the shell side vapor phase outlet of the organic solvent feeding preheater (5) is connected with the shell side inlet of the low-pressure tower top condenser (6) through a pipeline, and the shell side liquid phase outlet of the organic solvent feeding preheater (5) is connected with the organic solvent tank area (L) through a pipeline; the shell side outlet of the low-pressure tower top condenser (6) is connected with an organic solvent tank area (L) through a pipeline; the bottom of the low-pressure organic solvent rectifying tower (3) is respectively connected with the bottom of a low-pressure tower kettle reboiler (9) and an organic solvent heavy component separation device (K) through a pipeline, and the top of the low-pressure tower kettle reboiler (9) is connected with the lower part of the low-pressure organic solvent rectifying tower (3) through a pipeline; the shell side inlet of the organic solvent discharging cooler (11) is connected with a caprolactam water solution tank area (D) through a pipeline; the shell side outlet of the organic solvent discharging cooler (11) is connected with a caprolactam refining section (M) through a pipeline; the raw steam tank area (B) is respectively connected with a shell side inlet of the high-pressure tower kettle reboiler (7) and a shell side inlet of the medium-pressure tower kettle reboiler (8) through pipelines, and a shell side outlet of the high-pressure tower kettle reboiler (7) and a shell side outlet of the medium-pressure tower kettle reboiler (8) are respectively connected with the raw steam condensate tank area (H) through pipelines; the circulating cooling water tank area (E) is connected with the tube side of the low-pressure tower top condenser (6) through a pipeline and then is connected with the circulating water backwater tank area (F).
2. An ultralow energy consumption caprolactam organic extractant recovery device comprises a high-pressure wastewater stripping tower (21), a medium-pressure organic solvent rectifying tower (22), a low-pressure organic solvent rectifying tower (23), a wastewater feeding preheater (24), an organic solvent feeding preheater (25), a low-pressure tower top condenser (26), a high-pressure tower kettle reboiler (27), a medium-pressure tower kettle reboiler (28), a low-pressure tower kettle reboiler (29), a phase separation tank (30), an organic solvent discharging cooler (31), a high-pressure tower top auxiliary condenser (32), a first pump (34) and a second pump (33); the method is characterized in that: the waste water feeding tank area (A2) is sequentially connected with the waste water feeding preheater (24) and the upper part of the high-pressure waste water stripping tower (21) through pipelines, and the top of the high-pressure waste water stripping tower (21) is sequentially connected with the high-pressure tower top auxiliary condenser (32), the medium-pressure tower kettle reboiler (28) and the split-phase tank (30) through pipelines; the upper part of the phase-splitting tank (30) is connected with a waste water organic solvent tank area (I2) through a pipeline; the lower part of the split-phase tank (30) is connected with the upper part of the high-pressure wastewater stripping tower (21) after being connected with a first pump (34) through a pipeline; the bottom of the high-pressure wastewater stripping tower (21) is respectively connected with the bottom of a high-pressure tower kettle reboiler (27) and a shell side inlet of a wastewater feeding preheater (24) through pipelines; the top of the high-pressure tower kettle reboiler (27) is connected with the lower part of the high-pressure wastewater stripping tower (21) through a pipeline; the shell side outlet of the wastewater feeding preheater (24) is connected with a wastewater treatment working section (G2) through a pipeline; the organic solvent feeding tank area (C2) is connected with the organic solvent feeding preheater (25) through a pipeline and then is divided into two paths, one path is connected with the upper part of the medium-pressure organic solvent rectifying tower (22), the other path is connected with the upper part of the low-pressure organic solvent rectifying tower (23), and the top of the medium-pressure organic solvent rectifying tower (22) is sequentially connected with the low-pressure tower kettle reboiler (29) and the organic solvent discharging cooler (31) through pipelines and then is connected with the organic solvent tank area (L2); the bottom of the medium-pressure organic solvent rectifying tower (22) is respectively connected with the bottom of a reboiler (28) of the medium-pressure tower and an organic solvent heavy component separation device (K2) through pipelines; the top of the middle pressure tower kettle reboiler (28) is connected with the lower part of the middle pressure organic solvent rectifying tower (22) through a pipeline; the top of the low-pressure organic solvent rectifying tower (23) is connected with a shell side inlet of an organic solvent feeding preheater (25) through a pipeline; the shell side vapor phase outlet of the organic solvent feeding preheater (25) is connected with the shell side inlet of the low-pressure tower top condenser (26) through a pipeline, and the shell side liquid phase outlet of the organic solvent feeding preheater (25) is connected with the organic solvent tank area (L2) through a pipeline; the shell side outlet of the low-pressure tower top condenser (26) is connected with the organic solvent tank area (L2) through a pipeline; the bottom of the low-pressure organic solvent rectifying tower (23) is respectively connected with the bottom of a low-pressure tower kettle reboiler (29) and a second pump (33) through a pipeline, the second pump (33) is connected with the middle part of the medium-pressure organic solvent rectifying tower (22) through a pipeline, and the top of the low-pressure tower kettle reboiler (29) is connected with the lower part of the low-pressure organic solvent rectifying tower (23) through a pipeline; the shell side inlet of the organic solvent discharging cooler (31) is connected with a caprolactam water solution tank area (D2) through a pipeline; the shell side outlet of the organic solvent discharging cooler (31) is connected with a caprolactam refining section (M2) through a pipeline; the raw steam tank area (B2) is respectively connected with a shell side inlet of a high-pressure tower kettle reboiler (27), a shell side inlet of a medium-pressure tower kettle reboiler (28) and a split-phase tank (30) through pipelines; the shell side outlet of the high-pressure tower kettle reboiler (27) and the shell side outlet of the medium-pressure tower kettle reboiler (28) are respectively connected with a raw steam condensate tank area (H2) through pipelines; the circulating cooling water tank area (E2) is connected with the tube side of the low-pressure tower top condenser (26) through a pipeline and then is connected with the circulating water backwater tank area (F2).
3. A method for recycling caprolactam organic extractant with ultra-low energy consumption is characterized by comprising the following steps:
a) Use of the device of claim 1 or 2;
b) The operating pressure of the high-pressure wastewater stripping tower is controlled to be 0.1-1.0 MPaA, the operating pressure of the medium-pressure organic solvent rectifying tower is controlled to be 0.01-0.8 MPaA, the operating pressure of the low-pressure organic solvent rectifying tower is controlled to be 0.01-0.5 MPaA, and the top steam temperature of the high-pressure wastewater stripping tower is 5-50 ℃ higher than the bottom liquid temperature of the medium-pressure organic solvent rectifying tower; the temperature of the steam at the top of the medium-pressure organic solvent rectifying tower is 5-50 ℃ higher than that of the kettle liquid at the kettle of the low-pressure organic solvent rectifying tower;
c) The top steam of the high-pressure wastewater stripping tower provides a heat source for the medium-pressure organic solvent rectifying tower;
d) The top steam of the medium-pressure organic solvent rectifying tower provides a heat source for the low-pressure organic solvent rectifying tower;
e) The waste water feeding of the high-pressure waste water stripping tower exchanges heat with the discharging of the high-pressure waste water stripping tower kettle, the organic solvent feeding exchanges heat with the tower top steam of the low-pressure organic solvent rectifying tower, and the tower top steam condensate of the medium-pressure organic solvent rectifying tower exchanges heat with caprolactam water solution.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4422903A (en) * | 1981-02-17 | 1983-12-27 | Raphael Katzen Associates International Inc. | Anhydrous ethanol distillation method and apparatus |
| CN102391064A (en) * | 2011-09-19 | 2012-03-28 | 湖南百利工程科技有限公司 | Process for recovering and refining extracting agent in production procedure of hexanolactam |
| CN205774201U (en) * | 2016-05-25 | 2016-12-07 | 天津市天地创智科技发展有限公司 | A kind of super low energy consumption reclaims the device of caprolactam organic extractant |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4422903A (en) * | 1981-02-17 | 1983-12-27 | Raphael Katzen Associates International Inc. | Anhydrous ethanol distillation method and apparatus |
| CN102391064A (en) * | 2011-09-19 | 2012-03-28 | 湖南百利工程科技有限公司 | Process for recovering and refining extracting agent in production procedure of hexanolactam |
| CN205774201U (en) * | 2016-05-25 | 2016-12-07 | 天津市天地创智科技发展有限公司 | A kind of super low energy consumption reclaims the device of caprolactam organic extractant |
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