CN112933658B - Method and device for reducing solvent in raffinate oil of aromatic extraction device - Google Patents
Method and device for reducing solvent in raffinate oil of aromatic extraction device Download PDFInfo
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- CN112933658B CN112933658B CN202110109415.2A CN202110109415A CN112933658B CN 112933658 B CN112933658 B CN 112933658B CN 202110109415 A CN202110109415 A CN 202110109415A CN 112933658 B CN112933658 B CN 112933658B
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- raffinate oil
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D11/00—Solvent extraction
- B01D11/04—Solvent extraction of solutions which are liquid
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G21/00—Refining of hydrocarbon oils, in the absence of hydrogen, by extraction with selective solvents
- C10G21/28—Recovery of used solvent
Abstract
The invention belongs to the field of aromatic extraction production, and relates to a method and a device for reducing a solvent in raffinate oil of an aromatic extraction device. The method comprises the following steps: the process flow of blending raffinate oil, the upper circulation flow of raffinate oil, the aperture ratio of a tower tray of a raffinate oil washing tower and the injection rate are improved. In the device, outlets at the middle section and the upper section of a solvent separation tank are communicated with an eighth tower plate of a raffinate oil washing tower kettle, and a raffinate oil product enters from the bottom of the eighth tower plate of the raffinate oil washing tower kettle to be sprayed; and the raffinate oil at the lower outlet of the solvent separation tank is respectively communicated with the feed inlet of the raw material tank and the raffinate oil washing tower inlet of the raffinate oil washing tower, part of the raffinate oil from the lower outlet of the solvent separation tank is directly fed into the raw material tank, and the other part of the raffinate oil is fed into the feed inlet of the raffinate oil washing tower. The method and the device have the advantages of stable production operation, no flooding and phase mixing phenomenon of the water washing tower, less than 1ppm of the solvent content of the raffinate oil product after the transformation, and no filter element blockage phenomenon on the upper section and the middle section of the solvent separation tank.
Description
Technical Field
The invention relates to the field of aromatic extraction production, in particular to a method for improving the capacity of an aromatic extraction raffinate oil washing tower.
Background
The deviation of the original design material balance of the aromatic hydrocarbon device and the current operation data is large, when the device is operated at full load, the raffinate oil yield is 4.8-5.2 tons/hour, the original design yield is 4.094 tons/hour, the load of the raffinate oil washing tower is 120% of the original design, the washing production capacity of the raffinate oil washing tower is insufficient, the device is frequently flooded when the device is operated at ultrahigh load, the amount of the entrained solvent at an outlet cannot be controlled, the entrained solvent exceeds the design and is less than 4ppm, and the entrained solvent blocks a filter element of a rear-section equipment solvent separator, thereby affecting the quality of the raffinate oil product. Because of the high solvent content, the raffinate oil product can not be normally sent to a refining device, and only can return to a ethylene naphtha storage tank and enter a cracking device again, thereby causing the increase of production energy consumption and loss of benefit.
Disclosure of Invention
The invention aims to overcome the defect that the capacity of a washing tower of an aromatic extraction device is insufficient and the solvent removal effect of raffinate oil is poor in the prior art, and provides a method for reducing the solvent in the raffinate oil extracted by aromatic extraction.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
one aspect of the present invention provides a method and apparatus for reducing solvent in raffinate oil from aromatic extraction, the method comprising: the blending process flow of the raffinate oil is improved, the upper circulation flow of the raffinate oil is improved, the aperture ratio of a tower tray of a raffinate oil washing tower is reduced, and the injection rate is improved;
(1) The raffinate oil blending process flow is changed from an outlet at the middle and lower ends of the solvent separation tank V-102 to an inlet of a raffinate oil washing tower, namely part of raffinate oil from the outlet of the solvent separation tank V-102 is directly sent into a raw material tank, and the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon is blended, so that the content of the entrained solvent in the raffinate oil at the inlet of the raffinate oil washing tower is effectively reduced.
(2) The upper circulation flow of the raffinate oil is changed from an inlet pipeline of an original raffinate oil washing tower to a tower kettle of the raffinate oil washing tower, namely, a raffinate oil product enters from the bottom of an eighth tower plate of the tower kettle of the raffinate oil washing tower to be sprayed, and then the raffinate oil product is obtained from the top of the raffinate oil washing tower.
(3) The opening rate of the tower tray of the raffinate oil washing tower is reduced to 0.193 percent, and the injection rate is improved to
133.6-167.0cm/s。
In another aspect, the invention provides a device for reducing solvent in raffinate oil of an aromatic extraction device. The device comprises a raw material tank, an extraction tower, a raffinate oil washing tower and a solvent separation tank, wherein outlets at the middle section and the upper section of the solvent separation tank are communicated with an eighth tower plate of a raffinate oil washing tower kettle, and a raffinate oil product enters from the bottom of the eighth tower plate of the raffinate oil washing tower kettle to be sprayed, so that the upper circulation of the raffinate oil product is realized; the lower outlet of the solvent separation tank V-102 is respectively communicated with the feed inlet of the raw material tank and the raffinate oil washing tower inlet of the raffinate oil washing tower, part of raffinate oil from the lower outlet of the solvent separation tank V-102 is directly fed into the raw material tank to blend the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon, and the other part of raffinate oil is fed into the feed inlet of the raffinate oil washing tower.
Technical effects of the invention
After the improvement is implemented, the production operation is stable, the flooding and phase mixing phenomena do not occur in the water washing tower, the solvent content of the raffinate oil product is less than 1ppm after the improvement, the best quality is achieved for the operation of the device, the pressure difference of filter elements on the upper section and the middle section of the solvent separator is stable, and the filter element blockage phenomenon does not occur.
Drawings
FIG. 1 is a comparison of solvent content before and after raffinate oil product modification;
FIG. 2 is the original process flow of the raffinate oil washing tower;
FIG. 3 shows the process flow after changing the raffinate blending process flow and decreasing the hole opening ratio and increasing the injection rate.
Detailed Description
The invention aims to overcome the defect that the capacity of a washing tower of an aromatic extraction device is insufficient and the solvent removal effect of raffinate oil is poor in the prior art, and provides a method for reducing the solvent in the raffinate oil extracted by aromatic extraction.
FIG. 2 is the original process flow of the raffinate oil washing tower:
1. and (3) raffinate oil upper circulation flow: in order to ensure the separation effect of the raffinate oil washing tower, part of raffinate oil products are mixed with raffinate oil at the top of a solvent separation tank V-102 and then sent to the bottom of the raffinate oil washing tower T-103 for spraying, so that an extraction solvent carried in the raffinate oil is dissolved and separated, and then the raffinate oil products are obtained from the top of the raffinate oil washing tower T-103;
2. blending raffinate oil: in order to ensure that the ratio of non-aromatic hydrocarbons to aromatic hydrocarbons in the feedstock is 3:7, a portion of the raffinate product is returned to the feed tank to ensure the material ratio.
FIG. 3 is a process flow after changing raffinate blending process flow and reducing the hole opening ratio and increasing the injection rate:
1. and (3) raffinate oil upper circulation flow: and the raffinate oil product enters from the bottom of the eighth tower plate of the raffinate oil washing tower kettle to be sprayed, so that the spraying efficiency of the washing tower is ensured, the flow of raffinate oil at the feed inlet of the raffinate oil washing tower is reduced, and then the raffinate oil product is obtained from the top of the raffinate oil washing tower.
2. Blending raffinate oil: part of raffinate oil from the outlet of the solvent separation tank V-102 directly enters a raw material tank and is blended with the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon.
The invention provides a method for reducing solvent in aromatic extraction raffinate oil, which comprises the following steps:
(1) The raffinate oil blending process flow is changed from the extraction of the middle-section outlet and the upper-section outlet of the solvent separation tank V-102 into the extraction of raffinate oil from the lower-section outlet of the solvent separation tank V-102, and the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon in the raw material tank is blended.
Raffinate oil from an outlet of a raffinate oil washing tower is treated by a solvent separation tank V-102 in the middle and upper section to remove residual solvent, and then part of raffinate oil is led out and directly sent into a raw material tank to be blended with the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon, wherein the raffinate oil blending process flow in the prior art is improved as follows: unqualified raffinate oil which is not subjected to the washing process at the inlet of the raffinate oil washing tower, namely the outlet of the lower section of V-102 is directly sent to a raw material tank to be blended with the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon, and raffinate oil recycled by the improved raffinate oil blending process does not undergo raffinate oil washing tower operation, so that the process requirement of raw material blending composition is ensured, the feed quantity of the raffinate oil washing tower is greatly reduced, and the operation load of the raffinate oil washing tower is effectively reduced by about 30%.
(2) The raffinate oil upper circulation flow is changed from an original raffinate oil washing tower inlet pipeline to a raffinate oil washing tower kettle, namely, a raffinate oil product enters from the bottom of the eighth tower plate of the raffinate oil washing tower kettle to be sprayed, so that the spraying speed of the washing tower is ensured, the flow of raffinate oil at a feed inlet of the raffinate oil washing tower is reduced, the disperse phase distribution of the raffinate oil in the raffinate oil washing tower is more uniform, and the washing removal effect is improved.
(3) The opening rate of the tray of the raffinate oil washing tower is reduced to 0.193 percent, and the injection rate is increased to 133.6-167.0cm/s.
In the present invention, the absence does not mean absolute absence unless otherwise specified, and a component is considered to be absent from a stream when the content of the component in the stream is less than 1 ppm.
The aromatic extraction raffinate oil containing the extraction solvent is not particularly limited, and can be aromatic extraction raffinate oil containing the extraction solvent obtained by a conventional aromatic extraction process in the field, in the aromatic extraction process, the obtained raffinate oil inevitably contains a certain content of the extraction solvent, and the existence of the extraction solvent causes the reduction of the quality of the raffinate oil to a certain extent, so that the extraction solvent in the raffinate oil needs to be removed.
The composition of the raffinate oil is not particularly limited in the present invention, and may be any raffinate oil obtained by extraction of aromatic hydrocarbons in the art, and may further contain paraffins, naphthenes, olefins, and a small amount of aromatic hydrocarbons.
In the prior art, in order to remove the extraction solvent in the raffinate oil, a method of washing in a washing tower is mostly adopted, if the extraction solvent in the raffinate oil is to be completely removed, a washing tower with a larger capacity is needed, and if the washing tower has insufficient capacity, the extraction solvent in the raffinate oil is not completely removed, so that the quality of the raffinate oil is influenced. In order to take account of the two aspects of desolventizing effect and energy consumption, the invention creatively introduces and changes the blending process of raffinate oil and adjusts the aperture ratio of the tower plate of the water washing tower, thereby greatly optimizing the desolventizing effect of the extract solvent.
Example 1
(1) The raffinate oil washing feeding of the aromatic hydrocarbon device is 4.094 tons/hour, the raffinate oil blending process flow is changed from the outlet of the original raffinate oil washing tower to the inlet of the raffinate oil washing tower, the blending amount is 7 tons/hour, the effect is to ensure that the content ratio of non-aromatic hydrocarbon and aromatic hydrocarbon in the feeding of the extraction tower is 3:7, and the flow rate of the raffinate oil at the top of the extraction tower = that the original hydrogenated gasoline contains 4.094 tons/hour of non-aromatic hydrocarbon and 7 tons/hour of blending amount =11.094 tons.
(2) The tray of the raffinate oil washing tower is an 8-layer sieve plate tower, the single overflow and the aperture ratio are 0.193%, the injection rate is 133.6-167.0cm/s, raffinate oil feed enters from the bottom of the raffinate oil washing tower, flows upwards through the pores of the sieve plate and flows in the reverse direction with washing water entering from the top of the tower, a solvent carried in the raffinate oil is dissolved by water, and a water solvent at the bottom of the tower enters a water circulation system. And (4) discharging the washed raffinate oil from the top of the raffinate oil washing tower. The upper circulation function and the opening rate are used for ensuring the stable injection rate of the raffinate oil in sieve pores of the raffinate oil water washing tower, and certain injection rate is used for preventing the phenomena of miscible phase and flooding of the raffinate oil water washing tower.
(3) After the improvement is implemented, the production operation is stable, the raffinate oil washing tower does not generate flooding and miscible phase phenomena, the solvent content of the raffinate oil product is less than 1ppm after the improvement, the best quality is provided for the operation of the device, the pressure difference of filter elements on the upper section and the middle section of the solvent separator is stable, and the phenomenon of filter element blockage is not generated.
(4) And further carrying out the solvent separator V-102 of the shutdown, and analyzing the raffinate oil product at the top of the raffinate oil washing tower to be qualified, and verifying that the raffinate oil washing tower has an obvious transformation effect.
Figure 1 shows a comparison of solvent content before and after raffinate oil product modification.
In the process flow, part of raffinate oil returns to the raw material buffer tank for blending, the design is 7 tons/hour, the effect is to ensure that the content ratio of non-aromatic hydrocarbon to aromatic hydrocarbon in the feed of the extraction tower is 3:7, and the outlet flow of raffinate oil at the top of the extraction tower = original hydrogenated gasoline contains 4.094 tons/hour of non-aromatic hydrocarbon + the blending amount of 7 tons/hour =11.094 tons. Wherein the blending amount of raffinate oil is 7 tons, and circulation is formed between the extraction tower and the raffinate oil washing tower, a small amount of solvent (about 2000-5000 ppm) is continuously carried into the extraction tower, so that the solvent content in the feed of the raffinate oil washing tower is increased, and the solvent content in the raffinate oil is greatly reduced after the process is adjusted.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention and the equivalent alternatives or modifications according to the technical solution and the inventive concept of the present invention within the technical scope of the present invention.
Claims (1)
1. A method for reducing solvent in raffinate oil of an aromatic hydrocarbon extraction device is characterized by comprising a raw material tank, an extraction tower, a raffinate oil washing tower and a solvent separation tank, wherein outlets at the middle section and the upper section of the solvent separation tank are communicated with an eighth tower plate of a raffinate oil washing tower kettle, and a raffinate oil product enters from the bottom of the eighth tower plate of the raffinate oil washing tower kettle and is sprayed, so that the upper circulation of the raffinate oil product is realized; the lower outlet of the solvent separation tank V-102 is respectively communicated with the feed inlet of the raw material tank and the inlet of the raffinate oil washing tower, part of raffinate oil from the lower outlet of the solvent separation tank V-102 is directly fed into the raw material tank to blend the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon, and the other part of raffinate oil is fed into the feed inlet of the raffinate oil washing tower;
the method comprises the following steps: the raffinate oil blending process flow, the raffinate oil upper circulation flow, the raffinate oil washing tower tray aperture ratio reduction and the spray rate improvement are improved;
(1) Improving the raffinate oil blending process flow;
directly feeding part of raffinate oil from an outlet of a solvent separation tank V-102 into a raw material tank, and using the raffinate oil to match the proportion of non-aromatic hydrocarbon and aromatic hydrocarbon in the feed of an extraction tower; the ratio of non-aromatic hydrocarbons to aromatic hydrocarbons in the feed to the blending extraction column is 3:7 to 4:6;
(2) Improving the upper circulation flow of raffinate oil;
the raffinate oil upper circulation flow is changed from an original raffinate oil washing tower inlet pipeline into a raffinate oil washing tower kettle, namely, a raffinate oil product enters from the bottom of an eighth tower plate of the raffinate oil washing tower kettle to be sprayed, and then the raffinate oil product is obtained from the top of the raffinate oil washing tower;
(3) The opening rate of the tray of the raffinate oil washing tower is reduced to 0.193 percent, and the injection rate is increased to 133.6-167.0cm/s.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| GB1343621A (en) * | 1971-06-15 | 1974-01-16 | Universal Oil Prod Co | Solvent recovery process |
| JPH0613715B2 (en) * | 1986-04-18 | 1994-02-23 | 三菱油化株式会社 | Solvent recovery method |
| CN101914389B (en) * | 2009-09-18 | 2014-01-22 | 北京金伟晖工程技术有限公司 | Method for preparing high-quality diesel by double-hydrogenation system |
| CN201587930U (en) * | 2009-12-22 | 2010-09-22 | 北京金伟晖工程技术有限公司 | Reforming system for preparing aromatic hydrocarbons |
| CN103664478A (en) * | 2012-09-10 | 2014-03-26 | 中国石油化工股份有限公司 | Method for increasing yields of low-carbon olefins and aromatics by naphtha steam cracking |
| CN103725318B (en) * | 2012-10-16 | 2015-08-26 | 中国石油化工股份有限公司 | A kind of production method of aromatic hydrocarbon rubber extender oil |
| CN103803503B (en) * | 2012-11-07 | 2015-09-30 | 中国石油化工股份有限公司 | A kind of hydrogen peroxide extraction technique with side line tower |
| CN104449820B (en) * | 2013-09-13 | 2016-05-25 | 中国石油化工股份有限公司 | A kind of method that reduces the system of ethylene unit quench oil viscosity and improve solvent recovering rate |
| CN203807403U (en) * | 2014-05-21 | 2014-09-03 | 杨宁宁 | High-efficiency aromatics extraction device |
| US9221729B1 (en) * | 2015-02-23 | 2015-12-29 | Allnew Chemical Technology Company | Extractive distillation for aromatics recovery |
| CN109517619B (en) * | 2017-09-20 | 2021-12-10 | 北京安耐吉能源工程技术有限公司 | Solvent removing method for extracting raffinate oil from aromatic hydrocarbon |
| CN207193211U (en) * | 2017-09-20 | 2018-04-06 | 北京安耐吉能源工程技术有限公司 | A kind of gasoline system of processing |
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