CN117883807A - Efficient energy-saving vacuum crude benzene distillation method and device - Google Patents
Efficient energy-saving vacuum crude benzene distillation method and device Download PDFInfo
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- CN117883807A CN117883807A CN202311717070.4A CN202311717070A CN117883807A CN 117883807 A CN117883807 A CN 117883807A CN 202311717070 A CN202311717070 A CN 202311717070A CN 117883807 A CN117883807 A CN 117883807A
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- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 title claims abstract description 381
- 238000004821 distillation Methods 0.000 title claims abstract description 46
- 238000000034 method Methods 0.000 title claims abstract description 36
- 238000009833 condensation Methods 0.000 claims abstract description 41
- 230000005494 condensation Effects 0.000 claims abstract description 41
- 238000010992 reflux Methods 0.000 claims abstract description 17
- 238000005086 pumping Methods 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 73
- 239000012071 phase Substances 0.000 claims description 63
- 239000007788 liquid Substances 0.000 claims description 55
- 239000012808 vapor phase Substances 0.000 claims description 53
- 238000005192 partition Methods 0.000 claims description 25
- 239000007791 liquid phase Substances 0.000 claims description 23
- 239000000203 mixture Substances 0.000 claims description 22
- 238000001816 cooling Methods 0.000 claims description 13
- 238000005191 phase separation Methods 0.000 claims description 13
- 238000005406 washing Methods 0.000 claims description 11
- 238000000926 separation method Methods 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000012856 packing Methods 0.000 claims description 4
- 230000000630 rising effect Effects 0.000 claims description 4
- 238000003860 storage Methods 0.000 claims description 4
- 230000008569 process Effects 0.000 abstract description 13
- 238000004939 coking Methods 0.000 abstract description 8
- 230000008901 benefit Effects 0.000 abstract description 3
- 238000010828 elution Methods 0.000 abstract description 3
- 238000011112 process operation Methods 0.000 abstract description 3
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 150000001555 benzenes Chemical class 0.000 abstract description 2
- 238000011027 product recovery Methods 0.000 abstract description 2
- 239000000126 substance Substances 0.000 abstract description 2
- 230000000694 effects Effects 0.000 abstract 1
- 238000005265 energy consumption Methods 0.000 description 6
- 239000002351 wastewater Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- 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
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/005—Processes comprising at least two steps in series
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
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- Chemical Kinetics & Catalysis (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention belongs to the technical field of coking chemical product recovery, and particularly relates to a high-efficiency energy-saving vacuum crude benzene distillation method and device. Respectively pumping the non-condensed phase of benzene series at the top of the debenzolization tower by adopting two-stage vacuum equipment, so that the debenzolization tower is in a state lower than the operating pressure of the existing negative pressure crude benzene distillation, and an intermediate condenser is arranged at the rectifying section of the debenzolization tower to perform intermediate condensation reflux; the beneficial effects of the invention are as follows: the consumption of wash oil in the benzene elution process can be reduced, the process operation cost is reduced, and compared with the existing negative pressure superheated steam stripping crude benzene distillation process which is most widely applied, the process operation cost is reduced by 39.4%; the invention has the advantages of less equipment investment, good benzene removal effect, simple flow, low operation cost and the like.
Description
Technical Field
The invention belongs to the technical field of coking chemical product recovery, and particularly relates to a high-efficiency energy-saving vacuum crude benzene distillation method and device.
Background
The crude benzene distillation process commonly used in the coking industry generally comprises a normal pressure superheated steam stripping crude benzene distillation process and a negative pressure superheated steam stripping crude benzene distillation process; the technology of the normal pressure superheated steam stripping method crude benzene distillation process is mature and stable in operation, but the steam consumption for stripping in the process consumption tower is large, about 1.5 tons of 400 ℃ superheated steam is consumed for each 1 ton of crude benzene obtained, the treatment cost of the subsequent wastewater process is high, and the comprehensive energy consumption is large.
The negative pressure superheated steam stripping method crude benzene distillation process is to make the benzene removal system operate in a negative pressure state, and the operating pressure is generally controlled between-70 kPag and-40 kPag. Compared with the crude benzene distillation process by the normal pressure superheated steam stripping method, the process increases small investment of vacuum equipment and the like, but can greatly reduce the consumption of superheated steam, and about 0.75 to 0.8 ton of superheated steam is consumed per 1 ton of crude benzene, thereby further reducing the generation of wastewater and comprehensive energy consumption. The technology is the first crude benzene distillation technology in coking industry at present, and has wider application.
The rich oil temperature of the crude benzene distillation process is required to be high, the rich oil temperature and the high-quality steam are required to be heated to 180-185 ℃ and then enter a benzene removal tower for benzene distillation, and the lean oil operation temperature at the bottom of the benzene removal tower is 175-180 ℃; the prior crude benzene distillation process generally adopts a large amount of high-pressure superheated steam generated by a coke dry quenching device in a coking plant area, namely medium-pressure superheated steam obtained by temperature and pressure reduction, to heat rich oil and debenzolization steam for stripping. This steam application reduces the consumption of high quality steam quantities available for power generation.
The operation cost of the crude benzene distillation process is reduced, but the energy consumption ratio is still in the front of the gas purification device ratio, so that the energy consumption saving and the cost reduction are still important subjects for the research and development of a novel process for crude benzene distillation.
Disclosure of Invention
The invention aims to provide a high-efficiency energy-saving vacuum crude benzene distillation method and device, which overcome the defects of the prior art, reduce the temperature of wash oil in a benzene removal tower, lighten the deterioration degree of the wash oil, reduce the consumption of the wash oil in a benzene elution process, heat rich oil by using low-quality heat sources such as low-pressure steam and the like, reduce the dependence of the traditional coking crude benzene distillation process on high-quality heat sources, reduce fixed investment and operation cost, and have simple flow and little production wastewater.
In order to achieve the above purpose, the present invention is realized by the following technical scheme:
one of the technical proposal is as follows: the efficient energy-saving vacuum crude benzene distillation method is characterized by comprising the following specific steps of intermediate condensation heat exchange in a rectifying section of a debenzolization tower, primary oil vapor condensation and vacuumizing, secondary oil vapor condensation and vacuumizing and oil-water separation: 1) The middle condensation heat exchange of the rectifying section of the benzene removal tower, the hot rich oil after heat exchange and rich oil heating and temperature rise enters the middle part of the benzene removal tower, a baffle plate is arranged in the middle part of the rectifying section of the benzene removal tower, rising oil vapor and water vapor at the top below the baffle plate enter an intermediate condenser for partial condensation, vapor phase after partial condensation enters the bottom above the baffle plate, liquid phase after partial condensation enters a No. 2 oil-water separator for oil-water two-phase separation operation, and separated oil phase enters the top below the baffle plate; the 2# oil-water separator and the vapor phase pipeline after partial condensation are provided with pressure balance pipelines; the descending liquid at the bottom of the upper part of the partition plate flows into the top of the lower part of the partition plate along with the pipeline; 2) Condensing and vacuumizing the primary oil vapor, enabling crude benzene vapor and water vapor at the top of the debenzolization tower to enter a No. 1 condenser for condensation and cooling, and enabling a vapor-liquid mixture after condensation and cooling to enter a vapor-liquid separator for vapor-liquid two-phase separation; the vapor phase part after vapor-liquid separation is pumped to a No. 2 condenser through No. 1 vacuum equipment; 3) Condensing and vacuumizing the second-stage oil vapor, condensing and cooling the oil vapor pumped by the No. 1 vacuum equipment in a No. 2 condenser, and then entering a three-phase separator; pumping the separated non-condensing phase part to a benzene-washing front gas system through a No. 2 vacuum device; 4) Oil-water separation, wherein a liquid phase part separated by the vapor-liquid separator enters a No. 1 oil-water separator to carry out oil-water two-phase separation operation, one part of crude benzene oil phase separated by the two phases is pumped to the top of a benzene removal tower by a crude benzene reflux pump to be used as the top reflux, and the other part is used as a product to be sent to a storage procedure; a small amount of separated water separated by the three-phase separator is separated by a groove collecting port at the bottom of the three-phase separator; the crude benzene oil phase separated from the bottom of the three-phase separator is sent to the oil phase side of the No. 1 oil-water separator.
The temperature of the hot rich oil entering the middle part of the debenzolization tower in the step 1) is 135-155 ℃.
The bottom operation temperature of the debenzolization tower in the step 1) is 135-145 ℃.
The vapor phase temperature after the partial condensation of the intermediate condenser in the step 1) is 35-55 ℃.
The operating pressure at the top of the debenzolization tower in the step 1) is between 75kPag and 90kPag.
The temperature of the vapor-liquid mixture subjected to condensation cooling by the No. 1 condenser in the step 2) is 15-25 ℃.
The discharge pressure after the No. 1 vacuum equipment in the step 2) is-40 kPag to 60kPag.
The temperature of the vapor-liquid mixture subjected to condensation cooling by the No. 2 condenser in the step 3) is 15-25 ℃.
The second technical scheme is as follows: the high-efficiency energy-saving vacuum crude benzene distillation device is characterized by comprising a benzene removal tower, an intermediate condenser, a No. 1 oil-water separator, a No. 1 condenser, a vapor-liquid separator, a No. 2 oil-water separator, no. 1 vacuum equipment, a No. 2 condenser, a three-phase separator and No. 2 vacuum equipment, wherein an outlet at the top of the benzene removal tower is connected with a vapor phase inlet of the No. 1 condenser; the vapor-liquid mixture outlet of the No. 1 condenser is connected with the vapor-liquid mixture inlet of the vapor-liquid separator; the liquid phase outlet of the vapor-liquid separator is connected with a No. 1 oil-water separator; the oil phase outlet of the No. 1 oil-water separator is connected with a crude benzene reflux pump; the outlet of the crude benzene reflux pump is connected with a crude benzene inlet at the top of the debenzolization tower; the vapor phase outlet of the vapor-liquid separator is connected with the vapor phase inlet of the No. 1 vacuum equipment; the vapor phase outlet of the No. 1 vacuum equipment is connected with the vapor phase inlet of the No. 2 condenser; the vapor-liquid mixture outlet of the No. 2 condenser is connected with the vapor-liquid mixture inlet of the three-phase separator; the bottom oil phase outlet of the three-phase separator is connected with the oil phase side of the No. 1 oil-water separator; the vapor phase outlet of the three-phase separator is connected with the vapor phase inlet of the No. 2 vacuum equipment; the vapor phase outlet of the No. 2 vacuum equipment is connected with a gas system before benzene washing; a partition board is arranged in the middle of the rectifying section of the debenzolization tower, and a vapor phase outlet at the top below the partition board is connected with a vapor phase inlet of the intermediate condenser; the vapor phase outlet of the intermediate condenser is connected with the vapor phase inlet at the bottom above the partition plate; the condensed liquid phase outlet of the intermediate condenser is connected with a No. 2 oil-water separator; the oil phase outlet of the No. 2 oil-water separator is connected with the liquid phase inlet below the partition plate; the No. 2 oil-water separator is connected with a pressure balance pipeline arranged at a vapor phase outlet of the intermediate condenser; the liquid phase outlet above the baffle is connected with the liquid phase inlet below the baffle.
The benzene removing tower is any one of a packing type benzene removing tower, a plate type benzene removing tower or a benzene removing tower with a packing and plate type combined structure.
Compared with the prior art, the invention has the beneficial effects that:
1) Compared with the prior coking crude benzene distillation process, the low-oil operation temperature of the bottom of the debenzolization tower is 175-180 ℃, the temperature of the wash oil in the debenzolization tower is lower, the deterioration degree of the wash oil can be effectively restrained, the consumption of the wash oil in the benzene elution process is reduced, and the use cost of the wash oil raw material is reduced;
2) The operating pressure of the benzene removal tower is lower than that of the existing negative pressure crude benzene distillation process, the consumption of steam for stripping at the bottom of the benzene removal tower is lower, and about 0.4 ton of superheated steam is consumed for each 1 ton of crude benzene, so that the generation of crude benzene separation wastewater is greatly reduced, and the treatment cost of subsequent wastewater is reduced;
3) Compared with the most widely applied negative pressure superheated steam stripping method crude benzene distillation process, the process operation cost is reduced by 39.4 percent;
4) The rich oil entering the debenzolization tower in the process has lower temperature, and the cold rich oil obtained in the benzene washing process can be heated by using low-quality heat sources such as low-pressure steam after heat exchange of the hot lean oil at the bottom of the debenzolization tower, so that the dependence of the traditional coking crude benzene distillation process on high-quality heat sources is reduced.
Drawings
FIG. 1 is a schematic diagram of a process flow structure according to an embodiment of the present invention;
in the figure: 1-debenzolization tower, 2-intermediate condenser, 3-1# oil-water separator, 4-1# condenser, 5-vapour-liquid separator, 6-2# oil-water separator, 7-crude benzene reflux pump, 8-1# vacuum equipment, 9-2# condenser, 10-three-phase separator, 11-2# vacuum equipment and 101-baffle.
Detailed Description
The technical solutions of the present invention will be clearly and fully described below with reference to specific embodiments, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments.
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following description will briefly explain the embodiments that are needed in the embodiments or the prior art descriptions, and it is obvious that the embodiments in the following description are some embodiments of the present invention and that other embodiments may be obtained according to these embodiments without inventive effort for a person skilled in the art.
The components of the embodiments of the present invention generally described and illustrated in the specific embodiments herein can be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as provided in the specific embodiments, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.
The invention discloses a high-efficiency energy-saving vacuum crude benzene distillation device, which is shown in a figure 1, and comprises a benzene removal tower 1, an intermediate condenser 2, a No. 1 oil-water separator 3, a No. 1 condenser 4, a vapor-liquid separator 5, a No. 2 oil-water separator 6, a crude benzene reflux pump 7, no. 1 vacuum equipment 8, a No. 2 condenser 9, a three-phase separator 10 and No. 2 vacuum equipment 11, wherein the outlet at the top of the benzene removal tower 1 is connected with the vapor inlet of the No. 1 condenser 4; the vapor-liquid mixture outlet of the No. 1 condenser 4 is connected with the vapor-liquid mixture inlet of the vapor-liquid separator 5; the liquid phase outlet of the vapor-liquid separator 5 is connected with the No. 1 oil-water separator 3; the oil phase outlet of the No. 1 oil-water separator 3 is connected with a crude benzene reflux pump 7; the outlet of the crude benzene reflux pump 7 is connected with the crude benzene inlet at the top of the benzene removal tower 1; the vapor phase outlet of the vapor-liquid separator 5 is connected with the vapor phase inlet of the No. 1 vacuum equipment 8; the vapor phase outlet of the No. 1 vacuum equipment 8 is connected with the vapor phase inlet of the No. 2 condenser 9; the vapor-liquid mixture outlet of the No. 2 condenser 9 is connected with the vapor-liquid mixture inlet of the three-phase separator 10; the bottom oil phase outlet of the three-phase separator 10 is connected with the oil phase side pipeline of the No. 1 oil-water separator 3; the vapor phase outlet of the three-phase separator 10 is connected with the vapor phase inlet of the No. 2 vacuum equipment 11; the vapor phase outlet of the No. 2 vacuum equipment 11 is connected with a gas system before benzene washing; a partition board 101 is arranged in the middle of the rectifying section of the debenzolization tower 1, and a vapor phase outlet at the top below the partition board 101 is connected with a vapor phase inlet pipeline of the intermediate condenser 2; the vapor phase outlet of the intermediate condenser 2 is connected with a bottom vapor phase inlet pipeline above the partition plate 101; the condensed liquid phase outlet of the intermediate condenser 2 is connected with a pipeline of a No. 2 oil-water separator 6; the oil 6 phase outlet of the No. 2 oil-water separator is connected with a top liquid phase inlet pipeline below the partition plate 101; the No. 2 oil-water separator 6 is connected with a pressure balance pipeline arranged at the vapor phase outlet of the intermediate condenser 2, and a liquid phase outlet above the partition plate 101 is connected with a liquid phase inlet pipeline below the partition plate 101. The debenzolization tower 1 can be any one of a packed debenzolization tower, a plate debenzolization tower or a debenzolization tower with a combined structure of packing and plate.
The invention relates to a high-efficiency energy-saving vacuum crude benzene distillation method, which comprises the following specific steps of condensing and heat exchanging in the middle of a rectifying section of a benzene removal tower, condensing and vacuumizing primary oil vapor, condensing and vacuumizing secondary oil vapor and separating oil from water:
1) The middle condensation heat exchange of the rectifying section of the benzene removal tower, the hot rich oil after heat exchange and rich oil heating and temperature rise enters the middle part of the benzene removal tower 1, a baffle plate 101 is arranged in the middle part of the rectifying section of the benzene removal tower 1, rising oil vapor and water vapor at the top below the baffle plate 101 enter a middle condenser 2 for partial condensation, a vapor phase after partial condensation enters the bottom above the baffle plate 101, a liquid phase after partial condensation enters a No. 2 oil-water separator 6 for oil-water two-phase separation operation, and a separated oil phase enters the top below the baffle plate 101; the 2# oil-water separator 6 and the vapor phase pipeline after partial condensation are provided with pressure balance pipelines; the descending liquid at the bottom of the upper part of the partition plate 101 flows into the top of the lower part of the partition plate 101 along with the pipeline; the stripping steam for crude benzene distillation at the bottom of the debenzolization tower 1 is provided by lean oil regenerated oil-containing water steam or directly superheated steam; the temperature of the hot rich oil entering the middle part of the debenzolization tower 1 is 135-155 ℃; the operation temperature at the bottom of the debenzolization tower 1 is 135-145 ℃; the vapor phase temperature after partial condensation in the intermediate condenser 2 is 35-55 ℃.
2) The first-stage oil vapor condensation and vacuumizing, wherein crude benzene vapor and water vapor at the top of the debenzolization tower 1 enter a No. 1 condenser 4 for condensation and cooling, and a vapor-liquid mixture after condensation and cooling enters a vapor-liquid separator 5 for vapor-liquid two-phase separation; the vapor phase part after vapor-liquid separation is pumped to a No. 2 condenser 9 through a No. 1 vacuum device 8; the operating pressure at the top of the tower section of the debenzolization tower 1 is-75 kPag to-90 kPag; the temperature of the vapor-liquid mixture subjected to condensation cooling by the No. 1 condenser 4 is 15-25 ℃; the discharge pressure after the No. 1 vacuum apparatus 8 is-40 kPag to 60kPag.
3) The second-stage oil vapor is condensed and vacuumized, and the oil vapor pumped by the No. 1 vacuum equipment 8 enters a three-phase separator 10 after being condensed and cooled by a No. 2 condenser 9; pumping the separated non-condensing phase part to a benzene-washing front gas system through a No. 2 vacuum device 11; the temperature of the vapor-liquid mixture subjected to condensation cooling by the No. 2 condenser 9 is 15-25 ℃.
4) Oil-water separation, wherein a liquid phase part separated by the vapor-liquid separator 5 enters the No. 1 oil-water separator 3 to carry out oil-water two-phase separation operation, one part of crude benzene oil phase separated by the two phases is sent to the top of the benzene removal tower 1 by the crude benzene reflux pump 7 to be used as the top reflux, and the other part is used as a product to be sent to a storage procedure; a small amount of separated water separated by the three-phase separator 10 is separated by a groove collecting port at the bottom of the three-phase separator 10; the crude benzene oil phase separated from the bottom of the three-phase separator 10 is sent to the oil phase side of the No. 1 oil-water separator 3.
With a wash oil circulation of 300m 3 The actual production of crude benzene with a yield of 5.2t/h is exemplified by the following steps:
1) The rich oil sent in the benzene washing process exchanges heat with the hot lean oil extracted from the bottom of the benzene removal tower 1 to 130 ℃, and then is heated to 150 ℃ by 0.6MPag low-pressure steam and enters the middle part of the benzene removal tower 1; crude benzene steam and water steam at the top of the debenzolization tower 1 enter a No. 1 condenser 4 for condensation to 20 ℃ under the working condition that the operating pressure is-88 kPag and the operating temperature is 30 ℃, and the condensed and cooled vapor-liquid mixture enters a vapor-liquid separator 5 for vapor-liquid two-phase separation;
2) The liquid phase part separated by the vapor-liquid separator 5 enters a No. 1 oil-water separator 3 to carry out oil-water two-phase separation operation, one part of crude benzene oil phase after two-phase separation is sent to the top of the benzene removal tower 1 by a crude benzene reflux pump 7 to be used as the top reflux, and the other part is used as a product to be sent to a storage procedure;
3) The vapor phase part after vapor-liquid separation is pumped by a No. 1 vacuum device 8, and the discharge pressure after the No. 1 vacuum device 8 is 50kPag; sending to a No. 2 condenser 9 for condensation cooling to 20 ℃, then entering a three-phase separator 10, and separating a small amount of separated water by a groove collecting port at the bottom of the three-phase separator 10; the crude benzene oil phase separated from the bottom of the three-phase separator 10 is sent to the oil phase side of the No. 1 oil-water separator 3; pumping the separated non-condensing phase part to a benzene-washing front gas system through a No. 2 vacuum device 11;
4) A baffle plate 101 is arranged in the middle of the rectifying section of the debenzolization tower 1; the rising oil vapor and water vapor at the top of the lower part of the partition plate 101 enter the intermediate condenser 2 to exchange heat to 40 ℃ through circulating water, and the vapor phase after partial condensation enters the bottom of the upper part of the partition plate 101; the liquid phase after partial condensation enters a No. 2 oil-water separator 6 to carry out oil-water two-phase separation operation, and the separated oil phase enters the top below a partition plate 101; the 2# oil-water separator 6 and the vapor phase pipeline after partial condensation are provided with pressure balance pipelines; the descending liquid at the bottom of the upper part of the partition plate 101 flows into the top of the lower part of the partition plate 101 along with the pipeline; the hot lean oil with the bottom temperature of 138 ℃ in the debenzolization tower 1 is subjected to heat exchange with the rich oil sent by the benzene washing process to 36 ℃, and then is cooled to 27 ℃ by low temperature water and sent to the benzene washing process.
In the examples, benzene series mass fraction in lean oil at the bottom of the debenzolization tower is less than 0.15%. Saturated steam consumption for heating the rich oil is 6t/h under the condition of 0.6 MPa; the consumption of low-pressure superheated steam for direct stripping (or for regenerating lean oil) is 2t/h; the total consumption of the circulating water is 170m 3 And/h, the total consumption of low-temperature water is 370m 3 /h; compared with the most widely applied negative pressure superheated steam stripping method crude benzene distillation process, the operation cost of the process is reduced by 39.4 percent.
Economic benefit analysis of the embodiment of the invention: with a wash oil circulation of 300m 3 As an example, the crude benzene yield is 5.2t/h, and the energy consumption of the three crude benzene distillation processes is compared with that of the crude benzene distillation processTable 1.
TABLE 1
The operation cost of the three crude benzene distillation processes is as follows in sequence: the normal pressure superheated steam stripping process is more than the negative pressure superheated steam stripping process is more than the high-efficiency energy-saving vacuum crude benzene distillation process.
Compared with the existing crude benzene distillation process, the process provided by the invention has the advantages that the operation temperature of the wash oil is greatly reduced, so that the lean oil is not easy to deteriorate, the consumption of the wash oil is further reduced, and the energy consumption of the crude benzene distillation process is further greatly reduced.
Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (10)
1. The efficient energy-saving vacuum crude benzene distillation method is characterized by comprising the following specific steps of intermediate condensation heat exchange in a rectifying section of a debenzolization tower, primary oil vapor condensation and vacuumizing, secondary oil vapor condensation and vacuumizing and oil-water separation:
1) The middle condensation heat exchange of the rectifying section of the benzene removal tower, the hot rich oil after heat exchange and rich oil heating and temperature rise enters the middle part of the benzene removal tower, a baffle plate is arranged in the middle part of the rectifying section of the benzene removal tower, rising oil vapor and water vapor at the top below the baffle plate enter an intermediate condenser for partial condensation, vapor phase after partial condensation enters the bottom above the baffle plate, liquid phase after partial condensation enters a No. 2 oil-water separator for oil-water two-phase separation operation, and separated oil phase enters the top below the baffle plate; the 2# oil-water separator and the vapor phase pipeline after partial condensation are provided with pressure balance pipelines; the descending liquid at the bottom of the upper part of the partition plate flows into the top of the lower part of the partition plate along with the pipeline;
2) Condensing and vacuumizing the primary oil vapor, enabling crude benzene vapor and water vapor at the top of the debenzolization tower to enter a No. 1 condenser for condensation and cooling, and enabling a vapor-liquid mixture after condensation and cooling to enter a vapor-liquid separator for vapor-liquid two-phase separation; the vapor phase part after vapor-liquid separation is pumped to a No. 2 condenser through No. 1 vacuum equipment;
3) Condensing and vacuumizing the second-stage oil vapor, condensing and cooling the oil vapor pumped by the No. 1 vacuum equipment in a No. 2 condenser, and then entering a three-phase separator; pumping the separated non-condensing phase part to a benzene-washing front gas system through a No. 2 vacuum device;
4) Oil-water separation, wherein a liquid phase part separated by the vapor-liquid separator enters a No. 1 oil-water separator to carry out oil-water two-phase separation operation, one part of crude benzene oil phase separated by the two phases is pumped to the top of a benzene removal tower by a crude benzene reflux pump to be used as the top reflux, and the other part is used as a product to be sent to a storage procedure; a small amount of separated water separated by the three-phase separator is separated by a groove collecting port at the bottom of the three-phase separator; the crude benzene oil phase separated from the bottom of the three-phase separator is sent to the oil phase side of the No. 1 oil-water separator.
2. The efficient and energy-saving vacuum crude benzene distillation method as claimed in claim 1, wherein the temperature of the hot rich oil entering the middle part of the debenzolization tower in the step 1) is 135-155 ℃.
3. The efficient and energy-saving vacuum crude benzene distillation method as claimed in claim 1, wherein the bottom operation temperature of the debenzolization tower in said step 1) is 135-145 ℃.
4. The efficient and energy-saving vacuum crude benzene distillation method as claimed in claim 1, wherein the vapor phase temperature after partial condensation in the intermediate condenser in said step 1) is 35-55 ℃.
5. The efficient and energy-saving vacuum crude benzene distillation method as claimed in claim 1, wherein the operating pressure of the top of the debenzolization tower in the step 1) is-75 kPag to-90 kPag.
6. The efficient and energy-saving vacuum crude benzene distillation method according to claim 1, wherein the temperature of the vapor-liquid mixture condensed and cooled by the No. 1 condenser in the step 2) is 15-25 ℃.
7. The efficient and energy-saving vacuum crude benzene distillation method according to claim 1, wherein the discharge pressure after the 1# vacuum equipment in the step 2) is-40 kPag to 60kPag.
8. The efficient and energy-saving vacuum crude benzene distillation process according to claim 1, wherein the temperature of the vapor-liquid mixture condensed and cooled by the No. 2 condenser in the step 3) is 15-25 ℃.
9. The high-efficiency energy-saving vacuum crude benzene distillation device is characterized by comprising a benzene removal tower, an intermediate condenser, a No. 1 oil-water separator, a No. 1 condenser, a vapor-liquid separator, a No. 2 oil-water separator, no. 1 vacuum equipment, a No. 2 condenser, a three-phase separator and No. 2 vacuum equipment, wherein an outlet at the top of the benzene removal tower is connected with a vapor phase inlet of the No. 1 condenser; the vapor-liquid mixture outlet of the No. 1 condenser is connected with the vapor-liquid mixture inlet of the vapor-liquid separator; the liquid phase outlet of the vapor-liquid separator is connected with a No. 1 oil-water separator; the oil phase outlet of the No. 1 oil-water separator is connected with a crude benzene reflux pump; the outlet of the crude benzene reflux pump is connected with a crude benzene inlet at the top of the debenzolization tower; the vapor phase outlet of the vapor-liquid separator is connected with the vapor phase inlet of the No. 1 vacuum equipment; the vapor phase outlet of the No. 1 vacuum equipment is connected with the vapor phase inlet of the No. 2 condenser; the vapor-liquid mixture outlet of the No. 2 condenser is connected with the vapor-liquid mixture inlet of the three-phase separator; the bottom oil phase outlet of the three-phase separator is connected with the oil phase side of the No. 1 oil-water separator; the vapor phase outlet of the three-phase separator is connected with the vapor phase inlet of the No. 2 vacuum equipment; the vapor phase outlet of the No. 2 vacuum equipment is connected with a gas system before benzene washing; a partition board is arranged in the middle of the rectifying section of the debenzolization tower, and a vapor phase outlet at the top below the partition board is connected with a vapor phase inlet of the intermediate condenser; the vapor phase outlet of the intermediate condenser is connected with the vapor phase inlet at the bottom above the partition plate; the condensed liquid phase outlet of the intermediate condenser is connected with a No. 2 oil-water separator; the oil phase outlet of the No. 2 oil-water separator is connected with the liquid phase inlet below the partition plate; the No. 2 oil-water separator is connected with a pressure balance pipeline arranged at a vapor phase outlet of the intermediate condenser; the liquid phase outlet above the baffle is connected with the liquid phase inlet below the baffle.
10. The efficient and energy-saving vacuum crude benzene distillation unit as claimed in claim 9, wherein the benzene removal tower is any one of a packed benzene removal tower, a plate benzene removal tower or a combined structure benzene removal tower of packing and plate.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311717070.4A CN117883807A (en) | 2023-12-13 | 2023-12-13 | Efficient energy-saving vacuum crude benzene distillation method and device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311717070.4A CN117883807A (en) | 2023-12-13 | 2023-12-13 | Efficient energy-saving vacuum crude benzene distillation method and device |
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| CN117883807A true CN117883807A (en) | 2024-04-16 |
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| CN202311717070.4A Pending CN117883807A (en) | 2023-12-13 | 2023-12-13 | Efficient energy-saving vacuum crude benzene distillation method and device |
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| Country | Link |
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| CN (1) | CN117883807A (en) |
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