CN113680088A - Multi-effect rectification method, rectification device and application thereof - Google Patents
Multi-effect rectification method, rectification device and application thereof Download PDFInfo
- Publication number
- CN113680088A CN113680088A CN202010421210.3A CN202010421210A CN113680088A CN 113680088 A CN113680088 A CN 113680088A CN 202010421210 A CN202010421210 A CN 202010421210A CN 113680088 A CN113680088 A CN 113680088A
- Authority
- CN
- China
- Prior art keywords
- stage
- tower
- rectifying tower
- gas phase
- outlet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
- B01D3/322—Reboiler specifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Vaporization, Distillation, Condensation, Sublimation, And Cold Traps (AREA)
Abstract
The invention discloses a multi-effect rectification method, a rectification device and application thereof. The multi-effect rectification method comprises the following steps: the gas phase substances at the top of the first-stage to the N-1-stage rectifying tower are subjected to fractional condensation to obtain a condensate and a residual gas phase; the fractional condensation liquid flows back to the rectifying tower, the residual gas phase exchanges heat with the tower bottom liquid of the next-stage rectifying tower for condensation, the residual gas phase condensation liquid after heat exchange is extracted and/or flows back to the rectifying tower, and the tower bottom liquid after temperature rise returns to the next-stage rectifying tower; wherein N is an integer of 2 or more. The invention utilizes a dephlegmator to exchange heat between the gas phase material flow at the top of the rectifying tower and the bottom liquid of the next-stage rectifying tower, the gas phase material flow at the top of the rectifying tower is dephlegmated, and the bottom liquid of the next-stage rectifying tower is heated. The heavy components on the top of the tower can be condensed by using the method of fractional condensation on the top of the tower, and the content of the heavy components in the extracted condensate can be ensured to be qualified when the heavy components flow back into the tower, so that the reflux quantity of the tower is reduced, and the energy is saved.
Description
Technical Field
The invention belongs to the field of rectification, and particularly relates to a multi-effect rectification method, a rectification device and application thereof.
Background
Rectification is an energy-consuming major in chemical production, and in order to reduce energy consumption, various measures can be adopted, and multi-effect rectification is one of effective processes. The multi-effect rectification principle is the same as the multi-effect evaporation, the rectification tower is divided into a plurality of towers with different energy levels, the plurality of rectification towers with sequentially reduced pressure are connected in series, and the tower top steam of the former rectification tower is used as a heating medium of the reboiler of the latter rectification tower. Therefore, except the rectifying towers at the two ends, the intermediate rectifying device does not need to introduce a heating medium and a cooling medium from the outside, and the energy-saving effect is very obvious.
The multi-effect rectification is widely applied to the chemical industry, such as cyclohexane triple-effect rectification process in the process of preparing cyclohexanone by oxidizing cyclohexane, separation process of cumene oxidation product and cumene peroxide, and the like. The cyclohexane oxidation method for preparing cyclohexanone has a single-pass conversion rate of only about 5%, about 95% of cyclohexane needs to be recycled by rectification separation, and 60% of steam required by a device is consumed in the separation recycling process, so that the energy consumption of cyclohexane rectification is high, and the production cost of cyclohexanone is directly influenced. The cyclohexane adopts a triple-effect rectification process, the content of cyclohexanone and cyclohexanol in the recovered cyclohexane is lower than 0.05 wt%, the content of cyclohexane in a ketone alcohol product is lower than 5 wt%, and the energy-saving effect is obvious. Nevertheless, the essence of multi-effect rectification is rectification, and the multi-effect rectification still has energy-saving space starting from the aspect of reducing the requirement of the rectification process on energy and the like.
Disclosure of Invention
The invention provides an N-stage multi-effect rectification method, which comprises the following steps: the gas phase substances at the top of the first-stage to the N-1-stage rectifying tower are subjected to fractional condensation to obtain a condensate and a residual gas phase; the fractional condensation liquid flows back to the primary rectifying tower, the residual gas phase exchanges heat with the tower bottom liquid of the secondary rectifying tower for condensation, the residual gas phase condensation liquid after heat exchange is extracted and/or flows back to the primary rectifying tower, and the heated tower bottom liquid returns to the secondary rectifying tower; wherein N is an integer of 2 or more.
Exemplary N ═ 2, 3, or 4 according to embodiments of the present invention.
According to an embodiment of the invention, the fractional condensation may be performed in a fractional condenser.
According to an embodiment of the invention, the heat exchange condensation may be performed in a reboiler.
According to the embodiment of the invention, the gas phase at the top of the first-stage to N-1-stage rectifying tower is subjected to heat exchange condensation with the tower bottom liquid of the same-stage rectifying tower through a partial condenser and a reboiler which are connected in series, so that the processes of partial condensation and heat exchange condensation are realized.
According to the embodiment of the invention, tower bottoms of second-stage to Nth-stage rectifying towers exchange heat with gas phase at the top of the last-stage rectifying tower through a reboiler and a partial condenser which are connected in series to obtain heated tower bottoms, and the heated tower bottoms return to the tower bottom.
According to the embodiment of the invention, the material extracted from the tower bottom of the previous stage of rectifying tower is used as the feeding material of the next stage of rectifying tower, and the tower bottom liquid of the last stage of rectifying tower is extracted.
According to the embodiment of the invention, the gas phase at the top of the N-stage rectifying tower is subjected to fractional condensation to obtain the N-stage condensate and the N-stage residual gas phase.
According to an embodiment of the invention, the nth stage condensate is refluxed to the top of the nth stage rectification column.
According to an embodiment of the present invention, the nth stage residual gas phase is condensed and then withdrawn and/or refluxed to the nth stage rectification column. Further, the condensation may be performed in a condenser.
Specifically, the N-stage multi-effect rectification method is a three-effect rectification method, and the method comprises the following steps: the gas phase substances at the top of the first-stage rectifying tower and the second-stage rectifying tower are subjected to fractional condensation to obtain a first-stage condensate and a first-stage residual gas phase, and a second-stage condensate and a second-stage residual gas phase;
the first-stage condensate liquid flows back to the first-stage rectifying tower, the first-stage residual gas phase exchanges heat with the tower bottom liquid of the second-stage rectifying tower and is condensed, the residual gas phase condensate liquid after heat exchange is extracted and/or flows back to the rectifying tower, and the heated second-stage tower bottom liquid returns to the second-stage rectifying tower;
the second-stage condensate liquid flows back to the second-stage rectifying tower, the second-stage residual gas phase exchanges heat with the tower bottom liquid of the third-stage rectifying tower and is condensed, the residual gas phase condensate liquid after heat exchange is extracted and/or flows back to the rectifying tower, and the heated third-stage tower bottom liquid returns to the third-stage rectifying tower;
the gas phase substance at the top of the third-stage rectifying tower is subjected to fractional condensation to obtain a third-stage condensate and a third-stage residual gas phase; and the third-stage condensate liquid flows back to the third-stage rectifying tower, and the residual gas phase in the third stage is condensed and then extracted and/or flows back to the third-stage rectifying tower.
The invention also provides an N-stage multi-effect rectification device, which comprises: each of the first-stage to the Nth-stage rectifying units comprises a rectifying tower and a reboiler arranged at the tower bottom of each rectifying tower; wherein N is not less than 2 and is an integer;
a dephlegmator is arranged between the rectification units;
the gas phase at the top of the first-level to the N-1-level rectifying units exchanges heat and condenses with the tower bottom liquid of the first-level rectifying tower through a dephlegmator and a reboiler which are connected in series, so that dephlegmation and heat exchange condensation are realized;
and exchanging heat between tower bottoms of the second-stage rectifying tower and the Nth-stage rectifying tower with gas phase substances at the top of the previous-stage rectifying tower through a reboiler and a dephlegmator which are connected in series to obtain heated tower bottoms, and returning the heated tower bottoms to the tower kettle.
According to embodiments of the present invention, N ═ 2, 3, or 4 are exemplary.
According to an embodiment of the invention, the first-stage to the N-1 th-stage condensers each comprise a gas phase inlet, a residual gas phase outlet, a condensate outlet, a tower bottom liquid inlet and a tower bottom liquid outlet;
wherein the gas phase inlet is connected with the top gas phase outlet of the rectifying tower;
the residual gas phase outlet is connected with a heat exchange medium inlet of a secondary rectifying tower reboiler and is used as a heat exchange medium of tower bottom liquid;
and the condensate outlet is connected with the top of the rectifying tower or an external pipeline.
According to the embodiment of the invention, from the second-stage rectification unit, the tower bottom liquid outlet of the reboiler of each stage of the rectification tower is connected with the tower bottom liquid inlet of the dephlegmator of the previous stage of the rectification tower.
Further, the tower bottom liquid outlet of each stage of the condensers from the first stage to the N-1 stage is connected with the tower bottom of the next stage of the rectifying tower.
According to an embodiment of the invention, the first stage rectifier reboiler is supplied with heat from an external heat source.
According to the embodiment of the invention, the top gas phase outlet of the N stage rectifying tower is connected with the gas phase inlet of the N stage condenser. Further, a condensate outlet of the Nth-stage condenser is connected with the upper part of the Nth-stage rectifying tower. Further, the residual gas phase outlet of the Nth stage condenser is connected with an external pipeline or a condenser.
According to the embodiment of the invention, the fractional condensation and condensation of the gas phase at the top of the N-stage rectifying tower are cooled by an external refrigerant.
According to the embodiment of the invention, from the second stage rectification unit, the outlet of the heat exchange medium of the reboiler of each stage of the rectification tower is connected with the top of the previous stage rectification tower or with an external pipeline.
According to the embodiment of the invention, in the multi-effect rectifying device, the tower bottom of the previous rectifying tower is connected with the tower middle part of the next rectifying tower.
According to the embodiment of the invention, the tower bottom of the N-stage rectifying tower is connected with an external pipeline, and tower bottom liquid is extracted.
According to an embodiment of the present invention, the multi-effect rectification apparatus comprises: each of the first-stage to third-stage rectifying units comprises a rectifying tower, a reboiler arranged at the tower kettle of each rectifying tower and a dephlegmator;
the first-stage partial condenser and the second-stage partial condenser respectively comprise a gas phase inlet, a residual gas phase outlet, a condensate outlet, a tower bottom liquid inlet and a tower bottom liquid outlet;
the tower top gas phase outlet of the first-stage rectifying tower is connected with the gas phase inlet of the first-stage dephlegmator;
the residual gas phase outlet of the first-stage partial condenser is connected with a heat exchange medium inlet of a reboiler of a second-stage rectifying tower, and the condensate outlet of the first-stage partial condenser is connected with the top of the first-stage rectifying tower or an external pipeline; a tower bottom liquid outlet of the reboiler of the second-stage rectifying tower is connected with a tower bottom liquid inlet of the first-stage dephlegmator, and a tower bottom liquid outlet of the first-stage dephlegmator is connected with a tower bottom of the second-stage rectifying tower; the outlet of the heat exchange medium of the reboiler of the second-stage rectifying tower is connected with the top of the first-stage rectifying tower or an external pipeline;
a gas phase inlet of the second-stage partial condenser is connected with the top of the second-stage rectifying tower, a residual gas phase outlet of the second-stage partial condenser is connected with a heat exchange medium inlet of a reboiler of the third-stage rectifying tower, and a condensate outlet of the second-stage partial condenser is connected with the top of the second-stage rectifying tower or an external pipeline; a tower bottom liquid outlet of the reboiler of the third-stage rectifying tower is connected with a tower bottom liquid inlet of the second-stage partial condenser, and a tower bottom liquid outlet of the second-stage partial condenser is connected with a tower bottom of the third-stage rectifying tower; the outlet of the heat exchange medium of the reboiler of the third-stage rectifying tower is connected with the top of the second-stage rectifying tower or an external pipeline.
According to an embodiment of the invention, the multi-effect rectification method is carried out in the above-described multi-effect rectification apparatus.
The invention also provides the application of the multi-effect rectification method and/or the multi-effect rectification device in the rectification of cyclohexane or cumene peroxide or the multi-effect rectification of ethylene glycol.
The invention has the beneficial effects that:
the method utilizes a dephlegmator to exchange heat between the gas phase material flow at the top of the multi-effect rectifying tower and the bottom liquid of the next-stage rectifying tower, the gas phase material flow at the top of the tower is dephlegmated, and the bottom liquid of the next-stage rectifying tower is heated. The heavy components on the top of the tower can be condensed by using the method of fractional condensation on the top of the tower, and the content of the heavy components in the extracted condensate can be ensured to be qualified when the heavy components flow back into the tower, so that the reflux quantity of the tower is reduced, and the energy is saved.
Drawings
Fig. 1 is a schematic structural diagram of a triple-effect rectification apparatus provided in embodiment 1.
Reference numerals: t1, a first tower, T2, a second tower, T3, a third tower, B11, a first tower reboiler, B21, a second tower reboiler, B31, a third tower reboiler, C11, a first-stage partial condenser, C21, a second-stage partial condenser, C31, a third-stage partial condenser, C32 and a third tower condenser;
11. feed, 12, one-column overhead vapor stream, 13, one-column bottoms discharge, 14, first-stage dephlegmator residual vapor stream, 15, first-stage dephlegmator condensate, 16, one-column condensate, 17, one-column bottoms, 22, two-column overhead vapor stream, 23, two-column bottoms discharge, 24, second-stage dephlegmator residual vapor stream, 25, second-stage dephlegmator condensate, 26, two-column condensate, 27, two-column bottoms, 28, warmed two-column bottoms, 29, two-column return bottoms, 32, three-column overhead vapor stream, 33, three-column bottoms draw, 34, three-column dephlegmator residual vapor stream, 35, third-stage dephlegmator condensate, 36, three-column condensate, 37, three-column bottoms, 38, warmed three-column bottoms, 39, three-column return.
Detailed Description
As previously mentioned, the triple effect rectification method comprises: the gas phase substances at the top of the first-stage rectifying tower and the second-stage rectifying tower are subjected to fractional condensation to obtain a first-stage condensate and a first-stage residual gas phase, and a second-stage condensate and a second-stage residual gas phase;
the first-stage condensate liquid flows back to the first-stage rectifying tower, the first-stage residual gas phase exchanges heat with the tower bottom liquid of the second-stage rectifying tower and is condensed, the residual gas phase condensate liquid after heat exchange is extracted and/or flows back to the rectifying tower, and the heated second-stage tower bottom liquid returns to the second-stage rectifying tower;
the second-stage condensate liquid flows back to the second-stage rectifying tower, the second-stage residual gas phase exchanges heat with the tower bottom liquid of the third-stage rectifying tower and is condensed, the residual gas phase condensate liquid after heat exchange is extracted and/or flows back to the rectifying tower, and the heated third-stage tower bottom liquid returns to the third-stage rectifying tower;
the gas phase substance at the top of the third-stage rectifying tower is subjected to fractional condensation to obtain a third-stage condensate and a third-stage residual gas phase; and the third-stage condensate liquid flows back to the third-stage rectifying tower, and the residual gas phase in the third stage is condensed and then extracted or flows back to the third-stage rectifying tower.
According to an embodiment of the invention, the triple effect rectification method is used for rectification of cyclohexane.
Wherein, the feeding material of the first stage rectifying tower is a mixture containing cyclohexane, cyclohexanone and cyclohexanol. Furthermore, the mixture contains 90-97 wt% of cyclohexane, 0.5-3 wt% of cyclohexanone and 0.5-3 wt% of cyclohexanol; illustratively, it contains 95.3 wt% cyclohexane, 1.7 wt% cyclohexanol, 1.9 wt% cyclohexanone.
According to an embodiment of the invention, the temperature of the feed to the first stage rectification column is 140-.
According to an embodiment of the invention, the overhead operating pressure of the first rectification column is 450-.
According to an embodiment of the present invention, the operation temperature of the top of the first distillation column is 140-.
According to the embodiment of the invention, the operation temperature of the first distillation column is 140-155 ℃, such as 145-153 ℃, exemplary 145 ℃, 147 ℃, 150 ℃ and 153 ℃.
According to an embodiment of the invention, the still heat source of the first rectification column is provided by 0.5-1.5MPa vapour, such as 0.8-1.3MPa vapour, exemplarily 1.0MPa vapour.
According to an embodiment of the invention, the overhead operating pressure of the second rectification column is 250-.
According to the embodiment of the invention, the operation temperature of the top of the second distillation column is 118-.
According to the embodiment of the invention, the operation temperature of the bottom of the second distillation column is 120-.
According to an embodiment of the invention, the third rectification column is operated at a top pressure of 99 to 135kPa, such as 100 kPa 130kPa, illustratively 110kPa, 120kPa, 130 kPa.
According to an embodiment of the invention, the top operating temperature of the third rectification column is between 80 and 90 ℃, such as between 82 and 88 ℃, exemplary between 82 ℃, 83 ℃, 84 ℃, 85 ℃, 86 ℃, 88 ℃.
According to an embodiment of the invention, the third rectification column has a still operating temperature in the range of 90 to 100 ℃, such as 92 to 98 ℃, exemplarily 92 ℃, 93 ℃, 94 ℃, 95 ℃, 96 ℃, 98 ℃.
The technical solution of the present invention will be further described in detail with reference to specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.
In the following examples, the first column, the second column and the third column are all rectification columns.
Example 1
A triple effect rectification apparatus as shown in fig. 1, comprising:
the first stage rectification unit comprises a tower T1 and a tower reboiler B11 arranged at the bottom of a tower T1;
the second-stage rectification unit comprises a second tower T2 and a second tower reboiler B21 arranged at the bottom of the second tower T2;
the third stage rectification unit comprises a three-tower T3, a three-tower reboiler B31 arranged at the bottom of a three-tower T3, a third stage partial condenser C31 arranged at the top of the tower, and a three-tower condenser C32;
a first-stage dephlegmator C11 is arranged between the first-stage rectifying unit and the second-stage rectifying unit, and a first-stage dephlegmator C21 is arranged between the second-stage rectifying unit and the third-stage rectifying unit.
The first-stage partial condenser C11 and the first-stage partial condenser C21 respectively comprise a gas phase inlet, a residual gas phase outlet, a condensate outlet, a tower bottom liquid outlet and a tower bottom liquid outlet.
A gas phase inlet of the first-stage partial condenser C11 is connected with a gas phase outlet at the top of the first tower T1, a residual gas phase outlet of the first-stage partial condenser C11 is connected with a heat exchange medium inlet of the second tower reboiler B21, a condensate outlet of the first-stage partial condenser C11 is connected with the top of the first tower T1 and reflows to the first tower T1; a tower bottom liquid outlet of the second tower reboiler B21 is connected with a tower bottom liquid inlet of the first-stage partial condenser C11, and a tower bottom liquid outlet of the first-stage partial condenser C11 is connected with a tower bottom of the second tower T2; and the outlet of the heat exchange medium of the second tower reboiler B21 is connected with an external pipeline.
A gas phase inlet of the second-stage partial condenser C21 is connected with a gas phase outlet at the top of the second tower T2, a residual gas phase outlet of the second-stage partial condenser C21 is connected with a heat exchange medium inlet of a third tower reboiler B31, a condensate outlet of the second-stage partial condenser C21 is connected with the top of the second tower T2 and reflows to the third tower T3; a tower bottom liquid outlet of the three-tower reboiler B31 is connected with a tower bottom liquid inlet of a second-stage partial condenser C21, and a tower bottom liquid outlet of the second-stage partial condenser C21 is connected with a tower bottom of a three-tower T3; and the heat exchange medium outlet of the three-tower reboiler B31 is connected with an external pipeline.
A third stage partial condenser C31 and a third stage condenser C32 are arranged at the top of the third tower T3, a gas phase inlet of the third stage partial condenser C31 is connected with a gas phase outlet at the top of the third tower T3, a condensate outlet of the third stage partial condenser C31 is connected with the top of the third tower T3, a residual gas phase outlet of the third stage partial condenser C31 is connected with a heat exchange medium inlet of the third tower condenser C32, and a condensate outlet of the third tower condenser C32 is connected with an external pipeline; the third stage partial condenser C31 and the third tower condenser C32 are also provided with inlet and outlet of the refrigerant.
The tower kettle extract outlet of the first tower T1 is connected with the middle part of the second tower T2, the tower kettle extract outlet of the second tower T2 is connected with the middle part of the third tower T3, and the tower kettle extract outlet of the third tower T3 is connected with an external pipeline.
A column reboiler B11 is supplied with heat from an external heat source, and a column bottom liquid 17 is returned to a column bottom after being heated by a column reboiler B11.
EXAMPLE 2 triple Effect rectification of cyclohexane
Cyclohexane was rectified using the triple effect rectification apparatus provided in example 1. After the cyclohexane oxidation product is decomposed and waste alkali is separated and heat exchanged, a mixture of cyclohexane, cyclohexanone and cyclohexanol at 150 ℃ is obtained, the mixture is fed into a tower T1 as a feed 11, the operation pressure of the top of the tower at one tower is 500kPa, the operation temperature of the top of the tower is 143 ℃, the operation temperature of a tower kettle is 147 ℃, 1.0MPa steam is used for supplying heat to the first tower through a tower reboiler B11, the cyclohexane steam at the top of the first tower, namely the gas phase material flow 12 at the top of the first tower, is fed into a first-stage partial condenser C11 and exchanges heat with the tower bottom liquid of a second tower which is connected in series with the second tower reboiler B21, the gas phase material flow 12 at the top of the first tower is subjected to partial condensation by a cooling part, the amount of a condensation liquid 15 of the first-stage partial condenser is controlled by controlling a residual gas phase material flow 14 of the first-stage partial condenser, and the condensation liquid 15 of the first-stage partial condenser is used as a tower reflux liquid to return to the top of the first tower; and (3) feeding the residual gas phase material flow 14 of the first-stage partial condenser into a second-tower reboiler B21, and exchanging heat with second-tower bottom liquid 27 to obtain first-tower condensate 16 and heated second-tower bottom liquid 28, wherein the first-tower condensate 16 is cyclohexane, and the first-tower condensate 16 is extracted. And (3) after the heated tower bottom liquid 28 of the second tower passes through the first-stage partial condenser, obtaining tower bottom liquid 29 of a second tower return tower, and returning to the tower bottom of the second tower T2.
The bottom discharge 13 of the first tower enters a second tower T2, the top operating pressure of the second tower T2 is 300kPa, the top operating temperature is 123 ℃, the tower bottom operating temperature is 125 ℃, the gas-phase material flow 22 at the top of the second tower enters a second fractional condenser C21 and the three-tower bottom liquid 37 which is serially connected through a third tower reboiler B31 exchanges heat, part of the gas-phase material flow 22 at the top of the second tower is fractionated, the amount of the condensate 25 of the second fractional condenser is controlled by controlling the residual gas-phase material flow 24 of the second fractional condenser, and the condensate 25 of the second fractional condenser is returned to the top of the second tower as the reflux liquid of the second tower; and the residual gas phase material flow 24 of the second-stage partial condenser enters a three-tower reboiler B31 to exchange heat with the three-tower bottom liquid 37 to obtain two-tower condensate 26 and heated three-tower bottom liquid 38. The second tower condensate 26 is cyclohexane and is extracted. And (3) after the heated three-tower bottom liquid 38 passes through the second-stage partial condenser, obtaining three-tower return tower bottom liquid 39, and returning to the tower bottom of the three-tower T3.
And (3) feeding the bottom discharge 23 of the second tower into a third tower T3, wherein the tower top operating pressure of a third tower T3 is 110kPa, the tower top operating temperature is 84 ℃, the tower bottom operating temperature is 95 ℃, the gas-phase material flow 32 at the top of the third tower passes through a third stage partial condenser C31, circulating water is used as a refrigerant, the condensate 35 of the third stage partial condenser returns to the top of the third tower, and the residual gas-phase material flow 34 of the third stage partial condenser enters a condenser C32 to obtain the condensate 36 of the third tower and collect the condensate 36. The produced liquid 33 of the three-tower kettle is a mixture of cyclohexanone and cyclohexanol.
The cyclohexane three-tower rectifying unit in the 12.5t/h cyclohexanone device comprises a first tower condensate 16, a second tower condensate 26 and a third tower condensate 36 which are cyclohexane, and a third tower kettle produced liquid 33 which is a cyclohexanone and cyclohexanol mixture, wherein the content of ketone alcohol in the cyclohexane is lower than 0.05 wt%, and the content of cyclohexane in the ketone alcohol mixture is lower than 5 wt%.
Composition of feed 11: 95.3 wt% of cyclohexane, 1.7 wt% of cyclohexanol and 1.9 wt% of cyclohexanone, wherein the feeding amount is 360000kg/h, and the feeding temperature is 150 ℃. The overhead gas stream from the first column is 121000kg/h, the overhead gas stream from the second column is 139300kg/h and the overhead gas stream from the third column is 98500 kg/h.
One tower consumes 19.5t/h of 1.0MPa steam.
Comparative example
The requirements of the three-tower cyclohexane distillation on the feed and the distillate content are the same as those of the embodiment 1, except that a first-stage partial condenser, a second-stage partial condenser and a third-stage partial condenser are not arranged, and the steam at the top of the tower directly enters a reboiler of the next tower without passing through the partial condenser to be condensed. The content of the ketol in the extracted cyclohexane is controlled to be lower than 0.05 wt%, and the content of the cyclohexane in the ketol mixture extracted from the bottom of the three-tower is controlled to be lower than 5 wt%. The reflux ratios for the first, second and third columns were 0.64, 0.68 and 0.27, respectively. The steam consumption of one tower is 25t/h under 1.0 MPa.
By comparison, the partial condenser is added in the embodiment, and the steam consumption of the device is obviously reduced.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An N-stage multi-effect rectification method is characterized by comprising the following steps: the gas phase substances at the top of the first-stage to the N-1-stage rectifying tower are subjected to fractional condensation to obtain a condensate and a residual gas phase; the fractional condensation liquid flows back to the primary rectifying tower, the residual gas phase exchanges heat with the tower bottom liquid of the secondary rectifying tower for condensation, the residual gas phase condensation liquid after heat exchange is extracted and/or flows back to the primary rectifying tower, and the heated tower bottom liquid returns to the secondary rectifying tower; wherein N is an integer of 2 or more.
2. The method of claim 1, wherein N-2, 3, or 4.
Preferably, the fractional condensation is carried out in a fractional condenser.
Preferably, the heat exchange condensation is carried out in a reboiler.
3. The method as claimed in claim 1 or 2, wherein the gas phase at the top of the first to N-1 stage rectifying tower is condensed by the heat exchange of the tower bottom liquid of the same-stage rectifying tower through a partial condenser and a reboiler which are connected in series, so as to realize the processes of fractional condensation and heat exchange condensation.
Preferably, tower bottoms of the second-stage to the Nth-stage rectifying towers exchange heat with a gas phase at the top of the last-stage rectifying tower through a reboiler and a partial condenser which are connected in series to obtain heated tower bottoms, and the heated tower bottoms return to the tower kettle.
4. The method according to any one of claims 1 to 3, wherein the bottom of the previous rectifying tower is taken out as the feed of the next rectifying tower, and the bottom of the last rectifying tower is taken out.
Preferably, the gas phase at the top of the N-stage rectifying tower is subjected to fractional condensation to obtain an N-stage condensate and an N-stage residual gas phase.
Preferably, the Nth stage condensate is refluxed to the top of the Nth stage rectifying tower.
Preferably, the N stage residual gas phase is condensed and then extracted and/or refluxed to the N stage rectifying tower.
5. The method of claim 1 or 2, wherein the N-stage multi-effect rectification process is a three-effect rectification process, the method comprising: the gas phase substances at the top of the first-stage rectifying tower and the second-stage rectifying tower are subjected to fractional condensation to obtain a first-stage condensate and a first-stage residual gas phase, and a second-stage condensate and a second-stage residual gas phase;
the first-stage condensate liquid flows back to the first-stage rectifying tower, the first-stage residual gas phase exchanges heat with the tower bottom liquid of the second-stage rectifying tower and is condensed, the residual gas phase condensate liquid after heat exchange is extracted and/or flows back to the rectifying tower, and the heated second-stage tower bottom liquid returns to the second-stage rectifying tower;
the second-stage condensate liquid flows back to the second-stage rectifying tower, the second-stage residual gas phase exchanges heat with the tower bottom liquid of the third-stage rectifying tower and is condensed, the residual gas phase condensate liquid after heat exchange is extracted and/or flows back to the rectifying tower, and the heated third-stage tower bottom liquid returns to the third-stage rectifying tower;
the gas phase substance at the top of the third-stage rectifying tower is subjected to fractional condensation to obtain a third-stage condensate and a third-stage residual gas phase; and the third-stage condensate liquid flows back to the third-stage rectifying tower, and the residual gas phase in the third stage is condensed and then extracted or flows back to the third-stage rectifying tower.
6. An N-stage multi-effect rectification device, which is characterized by comprising: each of the first-stage to the Nth-stage rectifying units comprises a rectifying tower and a reboiler arranged at the tower bottom of each rectifying tower; wherein N is not less than 2 and is an integer;
a dephlegmator is arranged between the rectification units;
the gas phase at the top of the first-level to the N-1-level rectifying units exchanges heat and condenses with the tower bottom liquid of the first-level rectifying tower through a dephlegmator and a reboiler which are connected in series, so that dephlegmation and heat exchange condensation are realized;
and exchanging heat between tower bottoms of the second-stage rectifying tower and the Nth-stage rectifying tower with gas phase substances at the top of the previous-stage rectifying tower through a reboiler and a dephlegmator which are connected in series to obtain heated tower bottoms, and returning the heated tower bottoms to the tower kettle.
7. The apparatus of claim 6, wherein N-2, 3, or 4.
Preferably, the first-stage to the N-1 th-stage condensers comprise a gas phase inlet, a residual gas phase outlet, a condensate outlet, a tower bottom liquid inlet and a tower bottom liquid outlet;
wherein the gas phase inlet is connected with the top gas phase outlet of the rectifying tower;
the residual gas phase outlet is connected with a heat exchange medium inlet of a secondary rectifying tower reboiler and is used as a heat exchange medium of tower bottom liquid;
and the condensate outlet is connected with the top of the rectifying tower or an external pipeline.
8. The apparatus according to claim 6 or 7, wherein from the second stage rectification unit, the tower bottom outlet of the reboiler of each stage of the rectification tower is connected with the tower bottom inlet of the dephlegmator of the previous stage of the rectification tower.
Preferably, the tower bottom liquid outlet of each stage of the first stage to the N-1 stage of the condensers is connected with the tower bottom of the next stage of the rectifying tower.
Preferably, the first stage rectifier reboiler is supplied with heat from an external heat source.
Preferably, a gas phase outlet at the top of the nth-stage rectifying tower is connected with a gas phase inlet of the nth-stage condenser, a condensate outlet of the nth-stage condenser is connected with the upper part of the nth-stage rectifying tower, and a residual gas phase outlet of the nth-stage condenser is connected with an external pipeline or a condenser.
Preferably, from the second stage of rectification unit, the outlet of the heat exchange medium of the reboiler of each stage of rectification tower is connected with the top of the previous stage of rectification tower or with an external pipeline.
Preferably, in the multi-effect rectifying device, the tower bottom of the previous rectifying tower is connected with the tower middle part of the next rectifying tower.
Preferably, the tower bottom of the Nth-stage rectifying tower is connected with an external pipeline, and tower bottom liquid is extracted.
9. The apparatus of any one of claims 6-8, wherein the multi-effect rectification apparatus comprises: each of the first-stage to third-stage rectifying units comprises a rectifying tower, a reboiler arranged at the tower kettle of each rectifying tower and a dephlegmator;
the first-stage partial condenser and the second-stage partial condenser respectively comprise a gas phase inlet, a residual gas phase outlet, a condensate outlet, a tower bottom liquid inlet and a tower bottom liquid outlet;
the tower top gas phase outlet of the first-stage rectifying tower is connected with the gas phase inlet of the first-stage dephlegmator;
the residual gas phase outlet of the first-stage partial condenser is connected with a heat exchange medium inlet of a reboiler of a second-stage rectifying tower, and the condensate outlet of the first-stage partial condenser is connected with the top of the first-stage rectifying tower or an external pipeline;
a tower bottom liquid outlet of the reboiler of the second-stage rectifying tower is connected with a tower bottom liquid inlet of the first-stage dephlegmator, and a tower bottom liquid outlet of the first-stage dephlegmator is connected with a tower bottom of the second-stage rectifying tower; the outlet of the heat exchange medium of the reboiler of the second-stage rectifying tower is connected with the top of the first-stage rectifying tower or an external pipeline;
a gas phase inlet of the second-stage partial condenser is connected with the top of the second-stage rectifying tower, a residual gas phase outlet of the second-stage partial condenser is connected with a heat exchange medium inlet of a reboiler of the third-stage rectifying tower, and a condensate outlet of the second-stage partial condenser is connected with the top of the second-stage rectifying tower or an external pipeline; a tower bottom liquid outlet of the reboiler of the third-stage rectifying tower is connected with a tower bottom liquid inlet of the second-stage partial condenser, and a tower bottom liquid outlet of the second-stage partial condenser is connected with a tower bottom of the third-stage rectifying tower; the outlet of the heat exchange medium of the reboiler of the third-stage rectifying tower is connected with the top of the second-stage rectifying tower or an external pipeline.
10. Use of the multi-effect rectification method according to any one of claims 1 to 5 and/or the multi-effect rectification plant according to any one of claims 6 to 9 in the rectification of cyclohexane or cumene peroxide or the multi-effect rectification of ethylene glycol.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010421210.3A CN113680088B (en) | 2020-05-18 | 2020-05-18 | Multi-effect rectifying method, rectifying device and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010421210.3A CN113680088B (en) | 2020-05-18 | 2020-05-18 | Multi-effect rectifying method, rectifying device and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113680088A true CN113680088A (en) | 2021-11-23 |
| CN113680088B CN113680088B (en) | 2023-06-02 |
Family
ID=78575589
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010421210.3A Active CN113680088B (en) | 2020-05-18 | 2020-05-18 | Multi-effect rectifying method, rectifying device and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113680088B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103130227A (en) * | 2013-01-10 | 2013-06-05 | 天津大学 | Production device and production method for trichlorosilane full thermal coupling integration multi-effect distillation |
| CN106478368A (en) * | 2017-01-04 | 2017-03-08 | 天津市新天进科技开发有限公司 | The energy-saving rectifying process of production high grade edible spirit and device |
| CN107812393A (en) * | 2017-10-27 | 2018-03-20 | 烟台国邦化工机械科技有限公司 | A kind of methanol three-effect rectification system and technique |
| CN110697822A (en) * | 2019-09-18 | 2020-01-17 | 天津净润环保科技有限公司 | Method for recycling waste solvent of coating varnish |
-
2020
- 2020-05-18 CN CN202010421210.3A patent/CN113680088B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103130227A (en) * | 2013-01-10 | 2013-06-05 | 天津大学 | Production device and production method for trichlorosilane full thermal coupling integration multi-effect distillation |
| CN106478368A (en) * | 2017-01-04 | 2017-03-08 | 天津市新天进科技开发有限公司 | The energy-saving rectifying process of production high grade edible spirit and device |
| CN107812393A (en) * | 2017-10-27 | 2018-03-20 | 烟台国邦化工机械科技有限公司 | A kind of methanol three-effect rectification system and technique |
| CN110697822A (en) * | 2019-09-18 | 2020-01-17 | 天津净润环保科技有限公司 | Method for recycling waste solvent of coating varnish |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113680088B (en) | 2023-06-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4441117B2 (en) | Cascade reboiling of ethylbenzene / styrene tower | |
| CN102190559B (en) | Method and device for refining methanol by using divided wall distillation column | |
| CN101703840B (en) | Four-effect rectification system for synthesizing leather dimethyl formamide solution by wet method and recovery method | |
| RU2396242C2 (en) | Method of methanol recuperation | |
| CN105229119A (en) | Purifier apparatus and use the purification process of this purifier apparatus | |
| CN114031580B (en) | Refining device and refining method for low-energy PBAT byproduct tetrahydrofuran | |
| CN111233646B (en) | Rectification system for high-purity cyclohexanone and cyclohexanol and production process thereof | |
| CN110256202A (en) | A kind of refining crude methanol process of four towers quadruple effect | |
| CN105061187A (en) | A process for continuously producing m-toluic acid | |
| CN105237370A (en) | Method for producing cyclohexanone by cyclohexanol dehydrogenation | |
| CN111138246B (en) | Energy-saving process for recovering tert-butanol through ammoximation reaction | |
| CN103055530A (en) | Solvent reinforced transformation thermal coupling rectification system for separating cyclohexanone and phenol | |
| CN112745208B (en) | Cyclohexanone recovery and separation process and system | |
| CN105175302B (en) | Cumyl peroxide DCP device onrelevant tower differential pressure thermal coupling energy-saving methods | |
| CN101412653A (en) | Method for preparing phenylethylene by ethylbenzene gas-phase dehydrogenation and refining product of phenylethylene | |
| CN216106701U (en) | Device for separating cyclohexene | |
| CN113680088A (en) | Multi-effect rectification method, rectification device and application thereof | |
| CN105964007A (en) | Device and process for separating n-butyl alcohol and isobutanol mixture | |
| CN105646147B (en) | A kind of Methanol Recovery method | |
| CN105218342B (en) | A kind of cyclohexanol dehydrogenation produces the process of cyclohexanone | |
| CN113480395B (en) | Flash separation process and device for preparing ethylbenzene from ethylene-rich gas | |
| CN210314061U (en) | Rectification and purification device for synthesizing dimethyl oxalate by carbonylation of coal-made ethylene glycol | |
| CN109369488A (en) | A kind of cumyl peroxide DCP device heat integrated utilization method | |
| CN215975598U (en) | Device for refining cyclohexanone by cyclohexanol dehydrogenation | |
| CN217973033U (en) | Device for preparing cyclohexanol and coproducing cyclohexanone by cyclohexene method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |