CN1125008C - Process for recovering arylhydrocarbon by combination of extracting distillation with liquid-liquid extraction - Google Patents
Process for recovering arylhydrocarbon by combination of extracting distillation with liquid-liquid extraction Download PDFInfo
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Abstract
The present invention relates to a method for recovering benzene, toluene and xylene with high purities from a hydrocarbon mixture, particularly from the hydrocarbon mixture with high aromatic content with the adoption of the combined technique of extractive distillation and liquid-liquid extraction. In the method, a first distillation fraction containing the benzene and a second distillation fraction containing a small quantity of the benzene are obtained by the pre-fractional distillation of a raw material, wherein the product of the benzene is directly obtained by the extractive distillation treatment of the first distillation fraction, the second distillation fraction is mixed with raffinate oil obtained from the operation of the extractive distillation, and the mixture is used for the treatment of the liquid-liquid extraction to obtain the toluene containing a small quantity of the benzene. The technique with low energy consumption in the operations is suitable for the expansion reformation for an original liquid-liquid extraction device in a refining plant, and the benzene, the toluene and the xylene can be simultaneously recovered.
Description
The present invention is a kind of extractive distillation-liquid liquid extracting combination process, is applicable to reclaim the high purity aromatic hydrocarbon product from hydrocarbon mixture.
At present, the traditional method of aromatics separation mainly contains liquid liquid extraction process and extractive distillation method from hydrocarbon mixtures such as catalytic reformate or cracking hydrogenated gasoline.Liquid liquid extraction process can obtain high-purity benzene, toluene and dimethylbenzene (BTX) product with higher yields.But existing liquid liquid extraction process is suitable for handling the raw material that virtue contains 30～70 heavy %.Contain greater than 75 heavy % even the raw materials that reach 80～90 heavy % for virtue and then to be prone to raw material and the miscible phenomenon of solvent, need mix to convert with a large amount of non-aromatics products and raw material makes aromaticity content reduce to 70 heavy % to keep the normal running of extraction tower, and raw material mixes separation efficiency, the device processing power of converting the process that reduced, also increased the energy consumption of process, also can convert inhomogeneous appearance operation shakiness sometimes because of mixing.And extractive distillation is to utilize solvent method of aromatics separation to the difference of each component relative volatility of hydro carbons influence and from hydrocarbon mixture, need not carry out raw material and mix and convert.Be suitable for from close-cut fraction oil, reclaiming single aromatic hydrocarbon product, and be difficult in same extractive distillation series, obtain simultaneously highly purified BTX product.Generally speaking, extractive distillation technology is low than the aromatics yield of liquid liquid extraction process, and two kinds of treatment processs have his own strong points, and have certain complementarity, so the two combination process that combines is developed.
US3723256 has proposed a kind of extractive distillation-extractive combination process of liquid liquid.Its way is earlier raw material to be carried out prefractionation, cuts into benzene fraction and C
8The aromatic hydrocarbons fraction.The benzene fraction enters the extractive distillation section, obtains containing first logistics and the first non-aromatics fraction of benzene and solvent.C
8The aromatic hydrocarbons fraction enters solvent extraction that liquid liquid extracting section obtains containing aromatic hydrocarbons mutually and to contain taking out of non-aromatics mutually surplus, and gained extracting phase enters stripping stage again and handles, and obtains containing second fraction and the second non-aromatics fraction of aromatic hydrocarbons and solvent.The first and second non-aromatics fractions that above-mentioned processing is obtained are rework solution liquid extracting section again, second fraction that will contain aromatic hydrocarbons is introduced the solvent recuperation section with first fraction that contains benzene, separate solvent and aromatic hydrocarbons, wherein reclaiming solvent divides two strands of different positionss from recovery zone to draw, wherein one flows into extractive distillation section, another strand influent liquid extracting section.This method is extractive distillation and the combination of liquid liquid extraction process, and adopts a solvent recovery tower, is suitable for handling virtue and contains raw material greater than 75 heavy %, obtains high-purity BTX with higher yields simultaneously.But this method is applicable to new device, and operation energy consumption do not have remarkable reduction, is not suitable for existing liquid liquid extraction plant in the refinery is carried out capacity expansion revamping significantly.
Extractive distillation-liquid liquid extracting combination process that US3844902 proposes is incorporated in prefractionation and extractive distillation in the solvent tower and carries out, promptly in Distex process, raw material is separated into heavy arene and light two kinds of logistics of aromatic hydrocarbons, with the extractive distillation method heavy arene is separated with non-aromatic component again, the solvent that contains heavy arene then advances solvent recovery tower so that heavy arene and separated from solvent, reclaiming the mixture that cat head obtains toluene and dimethylbenzene, reclaiming solvent and return solvent tower again.Enter extraction tower after non-aromatics that Distex process produces and the light aromatic hydrocarbons cooling and carry out the extracting of liquid liquid, cat head gets non-aromatics, and the solvent that is rich in aromatic hydrocarbons at the bottom of the tower then obtains light aromatic hydrocarbons through stripping tower, solvent recovery tower, and light aromatic hydrocarbons is the mixture of benzene and toluene.Owing to do not establish prefractionation, directly in solvent tower, light aromatics is separated with heavy arene, light aromaticss a large amount of in this process need be discharged solvent tower through distillation, and then enter the extracting of liquid liquid and carry out the liquid phase extracting, handle through distillations such as stripping distillation and solvent recuperation again and just can obtain the pure aromatics product, and still be mixture, obtain purified petroleum benzin and also need further rectifying.Light aromatics need be repeatedly evaporated in obvious above-mentioned technological operation, is suitable for handling low and the raw material that heavy aromatics content is high of light aromaticity content.For cracking hydrogenated gasoline and the very high raw material of the light aromaticity content of this class of coal tar,, the increase of operation energy consumption will be caused because need repeatedly evaporate light aromatic hydrocarbons and use the extracting of liquid liquid to separate light aromatic hydrocarbons.
The purpose of this invention is to provide and obtain purified petroleum benzin a kind of can directly the separation, and can reclaim the extractive distillation-liquid liquid extracting combination process of toluene and dimethylbenzene simultaneously.This process energy consumption, material consumption are lower, the aromatics yield height.
The present invention utilizes the selectivity different characteristics of same arenes selectivity solvent in extractive distillation and the extracting of liquid liquid, adopts extractive distillation-liquid liquid extracting combination process to light fraction in the raw material with heavy fraction carries out extractive distillation respectively and the extracting of liquid liquid is handled.Directly obtain qualified benzaldehyde product in extractive distillation unit solvent recuperation column overhead, the recovery tower place obtains highly purified toluene and benzene in liquid liquid extracting unit.
Method of the present invention comprises the steps:
(1) hydrocarbon mixture is carried out prefractionation, obtaining benzene concentration is first fraction of 60.0～95.0 heavy % and second fraction that benzene concentration is 0.5～30.0 heavy %;
(2) first fraction is sent into solvent tower, obtain being rich in the solvent of benzene with arenes selectivity dissolution with solvents benzene wherein, this solvent that is rich in benzene is sent into the extractive distillation solvent recovery tower arenes selectivity solvent is separated with benzene, the lean solvent that obtains at the bottom of this recovery tower returns the extractive distillation cat head;
(3) send into liquid liquid extraction tower after the mixing of raffinating oil that the extractive distillation cat head is discharged with described second fraction with in (2) step, obtain being rich in the solvent of aromatic hydrocarbons with arenes selectivity dissolution with solvents aromatic hydrocarbons wherein, the solvent that is rich in aromatic hydrocarbons is sent into stripping tower, the logistics that discharge on stripping tower top, aromatic hydrocarbons rework solution liquid extraction tower promptly refluxes, the solvent that contains aromatic hydrocarbons that discharge the stripping tower bottom enters liquid liquid extraction solvent recovery tower, obtain pure aromatics at this recovery tower top, the lean solvent rework solution liquid extracting cat head of discharging at the bottom of the recovery tower.
In the described method, first fraction that prefractionation is told is mainly the benzene fraction that contains non-aromatics; Second fraction is mainly the blending fraction of benzene and toluene, and wherein the content of benzene is less, and the heavy constituent that prefractionation is told are discharged from system, is mainly the material that contains dimethylbenzene, can be used as the isomerization of C-8 aromatics raw material.
The operational condition of above-mentioned prefractionation preferably is controlled at and makes that benzene concentration is 70.0～95.0 heavy % in institute's fraction of winning; Benzene concentration is 0.5～15.0 heavy % in second fraction, is preferably 2.0～10.0 heavy %.
For increasing the dissolving power of tetramethylene sulfone to non-aromatics, improve the benzene rate of recovery and the operating severity that relaxes solvent recuperation in the Distex process, the present invention adds C in the arenes selectivity solvent in the described extractive distillation of step (2)
8～C
10Aromatic hydrocarbons as solubility promoter.Solubility promoter is selected from C
8～C
10In the aromatic hydrocarbons any one or their mixture, as p-Xylol, o-Xylol, m-xylene, trimethylbenzene or durene, preferred solubility promoter is a dimethylbenzene.The content of described solubility promoter in the arenes selectivity solvent is 0.1～15.0 heavy %, is preferably 3.0～8.0 heavy %.
The content of aromatic hydrocarbons is 60.0～98.0 heavy % in the used hydrocarbon mixture of the inventive method, and preferably selecting benzene content for use is the hydrocarbon mixture of 30.0～90.0 heavy %.
The inventive method through after prefractionation is divided into two fractions, is carried out extractive distillation operation with first fraction with hydrocarbon mixture, and the non-aromatics component that the extractive distillation operation produces is promptly raffinated oil and carried out liquid liquid extraction procedure after second fraction mixes.Extractive distillation and the employed solvent of liquid liquid extraction procedure are with a kind of material, but independent separately, do not use with mutually mutually, can contain minor amount of water like this in the liquid liquid extraction procedure solvent to improve separation efficiency, and suitable water-content is 0.3～1.0 heavy %.Not moisture in the extractive distillation solvent, reduce the aromatic hydrocarbons separation efficiency variation that causes with quality and the solvent solubility of avoiding influencing to purified petroleum benzin.
The used arenes selectivity solvent of the present invention can be selected from sulfone class, glycols or N-formyl morpholine, and the general expression that described sulfone class has is:
R in the formula
1, R
2, R
3, R
4Be selected from hydrogen, C respectively
1～C
10Alkyl, C
7～C
12Aralkyl, C
1～C
8Alkoxyl group.Comparatively preferred solvent is tetramethylene sulfone, 2-methyl sulfolane or 2, and 4-dimethylsulfolane, highly preferred solvent are tetramethylene sulfone.
Following accompanying drawing helps further understanding of the present invention.
Fig. 1 is the schematic flow sheet of combination process of the present invention.
Fig. 2 reclaims the schematic flow sheet of benzene for adopting extractive distillation technology.
As shown in Figure 1, hydrocarbon mixture enters prefractionator 2 through pipeline 1 from the middle and lower part, and prefractionator 2 can be selected a common destilling tower, obtains containing the first fraction of benzene at cat head, obtains containing the second fraction of a small amount of benzene at the tower middle part, gets mixed xylenes at the bottom of the tower; Prefractionation also can adopt two destilling towers mutually to contact, one in the tower of series winding is benzene faction cut tower, another is deheptanizer, so then obtain to contain the first fraction of benzene in benzene faction cut column overhead, obtain to contain the second fraction of a small amount of benzene at the deheptanizer cat head, obtain mixed xylenes at the bottom of the tower. The mixed xylenes that prefractionation is told is through pipeline 15 dischargers.
The gas phase that contains benzene the first fraction that prefractionator 2 cats head steam is discharged by pipeline 3, after condensation, enter extraction distillation tower 4 by the middle part, the arenes selectivity solvent enters extraction distillation tower 4 by pipeline 10 from cat head, the cat head light component is mainly non-aromatic component, discharged by pipeline 6, rich solvent enters extractive distillation solvent recovery tower 9 through pipeline 8 by the middle part at the bottom of the tower. These recovery tower 9 top gaseous phases enter basin 12 after condenser 11 condensations, incoagulable gas is discharged by pipeline 14, benzaldehyde product is discharged from basin 12, a part passes back into recovery tower 9, another part is discharged by pipeline 13, and the lean solvent that obtains at the bottom of recovery tower 9 towers returns extraction distillation tower 4 tops by pipeline 10.
The second fraction that the cutting of prefractionator 2 side lines obtains, be mainly the toluene fraction that contains a small amount of benzene, discharged by extraction distillation tower side line 5, the non-aromatic component of discharging with extractive distillation overhead line 6 mixes the middle and lower part that enters liquid liquid extraction tower 16 by pipeline 7, the extracting of liquid liquid take out remaining phase, being mainly the non-aromatics material is discharged by overhead line 30, extracting is mutually for containing the solvent of aromatic hydrocarbons, discharged the top of sending into stripper 18 through pipeline 17 by tower bottom, through the stripping distillation, gaseous component enters basin 20 by pipeline 19 discharges after condensation, discharge as backflow aromatic hydrocarbons from basin 20 again and be back to the bottom of liquid liquid extraction tower 16 through pipeline 21, with contained aromatic hydrocarbons in this logistics of further recovery. The rich solvent that contains aromatic hydrocarbons that discharge stripper 18 bottoms enters the middle part of liquid liquid extraction solvent recovery tower 23 through pipeline 22, the logistics that discharge at these recovery tower 23 tops, after condenser 25 coolings, enter basin 26, the effluent of discharging from basin 26 is the pure aromatics of toluene and a small amount of benzene, a part passes back into recovery tower 23 by pipeline 28, and another part is by pipeline 29 discharge systems. The pure aromatics of being discharged by pipeline 29 can pass through further rectifying and separating benzene and toluene, does not mark among Fig. 1. Recycling through the top of pipeline 24 rework solution liquid extraction towers by the lean solvent that discharge recovery tower 23 bottoms.
In the above-mentioned flow process, the lean solvent that reclaim extractive distillation solvent recovery tower 9 bottoms should some send solvent regeneration tower regeneration, and it is recycling that another part returns extraction distillation tower 2 tops. Equally, the lean solvent that reclaim liquid liquid extraction solvent recovery tower 23 bottoms also should some send solvent regeneration tower regeneration, and another part rework solution liquid extraction tower 16 tops are recycling. Described solvent reclamation operation is well-known to those skilled in the art, does not mark among Fig. 1.
When using group technology of the present invention, each tower operating parameter is: prefractionator 2 is the air-distillation operation, its tower top temperature is controlled at 70～85 ℃, and column bottom temperature is controlled at 105～155 ℃, and the temperature of tower side line the second fraction outlet is 90～120 ℃. Extraction distillation tower 4 cat head operating pressures are 0.1～0.3MPa, the ratio of solvent and the first fraction mass flow, namely ratio of solvent is controlled at 2.0～5.5, and it is 80～130 ℃ that solvent enters the tower temperature, preferably contain 0.1～15.0 heavy % in the separative efficiency solvent for improving, preferably contain the C of 3.0～8.0 heavy %8～C
10Aromatic hydrocarbons is as cosolvent. Extractive distillation solvent recovery tower 9 cat head operating pressures are 0.040～0.1MPa, and rich solvent enters 125～180 ℃ of tower temperature. Solvent and the second fraction mass flow ratio are 3.0～5.0 in the liquid liquid extraction tower 16, backflow aromatic hydrocarbons is 0.5～0.8 with the ratio of the second fraction mass flow, liquid liquid extraction solvent water content is 0.3～0.8 heavy %, and entering the tower temperature is 60～100 ℃, and the cat head operating pressure is controlled at 0.7～0.8MPa. It is 100～120 ℃ that the rich solvent that enters stripper 18 enters the tower temperature, and stripper 18 bottom operating pressures are controlled at 0.18～0.35MPa, and solvent is 0.5～0.7 with the ratio of aromatic hydrocarbons mass flow in this tower. Water stripping is 0.020～0.040 with the ratio of quantity of solvent in the liquid liquid extraction solvent recovery tower 23, and operating pressure is 0.06～0.09MPa at the bottom of the tower, and operating temperature is 165～180 ℃ at the bottom of the tower.
The inventive method is suitable for reclaiming BTX the hydrocarbon mixture of the high benzene content more than containing the heavy % of benzene 30. Be specially adapted to from hydrogenated pyrolysis gasoline, coal tar wet goods raw material, reclaim aromatic hydrocarbons, and can directly obtain benzaldehyde product.
The group technology that the present invention proposes is set up the extractive distillation unit in the liquid liquid extraction process of routine, only need increase a small amount of equipment and it can be transformed into the device that is suitable for reclaiming BTX from the hydro carbons of high benzene content. In group technology, because the existence of extractive distillation unit, the load of liquid liquid extracting unit reduces greatly, and benzene and evaporation of water amount reduce, but therefore decrease energy consumption reduces solvent consumption simultaneously. Group technology of the present invention can reclaim benzene, toluene and dimethylbenzene simultaneously, compares with simple liquid liquid extraction process or with the disclosed group technology of USP3844902, can in the situation that guarantees product purity and aromatics yield, further reduce energy consumption.
Further specify the present invention below by example, but the present invention is not limited to this.
The design of solvent tower, extractive distillation solvent recovery tower, liquid liquid extraction tower, stripping tower, liquid liquid extraction solvent recovery tower and operation are provided by the process simulation computed in software according to raw material composition and treatment capacity in the example.
Example 1
This example adopts combination process of the present invention to reclaim BTX simultaneously from hydrocarbon mixture.
With the cracking hydrogenated gasoline is raw material, and tetramethylene sulfone is a solvent, adopts combination process of the present invention to reclaim BTX simultaneously.First fraction and second fractional composition and flow see Table 1 after raw materials used composition, the prefractionation, and each tower operational condition sees Table 2, reclaim quality product and install the wastage in bulk or weight index to see Table 3.
Example 2
This example reclaims BTX according to the combined technical method of example 1 from the cracking hydrogenated gasoline.Different is to add o-Xylol as solubility promoter in the extractive distillation solvent, and the content of o-Xylol in solvent is 4.5 heavy %.Each tower operational condition sees Table 2, reclaims quality product and consumption indicators and sees Table 3.
As shown in Table 2, behind the adding solubility promoter, the working pressure of solvent tower and temperature obtain relaxing in the extractive distillation solvent.The inlet amount of liquid liquid extraction tower reduces, and liquid liquid extracting unit load therefore descends.By table 3 data as can be known, adding solubility promoter has no adverse effects to reclaiming quality product.
Comparative Examples 1
Adopt conventional liquid liquid extraction process to reclaim aromatic hydrocarbons, promptly adopting preliminary fractionator that raw material is separated into first fraction and the xylene content that xylene content is 0.1 heavy % earlier is second fraction of 99.0 heavy %, then second fraction is discharged system, first fraction is sent into liquid liquid extraction tower, obtains highly purified benzene and toluene through extracting, stripping and solvent recovery step.Liquid liquid extraction process is raw materials used with example 1, each tower operational condition and reclaim that the aromatic hydrocarbons quality sees Table 2 respectively, table 3.
Contrasted as can be known by table 2, table 3 data, the solvent of the solvent tower of combination process of the present invention when operational temperature conditions is moderate, the operational condition of liquid liquid extracting part and simple liquid liquid extraction process basically identical.Under the suitable situation of quality product and aromatic recovery rate, the energy consumption of combination process reduces significantly, and particularly the comparable simple liquid liquid extraction process of steam consumption descends more than 22% the also corresponding reduction of extraction solvent consumption.
Example 3
The explanation of this example adds the effect of solubility promoter in the extractive distillation solvent.
Adopt extractive distillation flow process shown in Figure 2 to reclaim benzene.Hydrocarbon feed enters preliminary fractionator 2 by pipeline 1 among Fig. 2, and the benzene content that cat head fractionates out is that first fraction of 86.0 heavy % enters solvent tower 4 by pipeline 3, and the benzene content at the bottom of the tower is that second fraction of 0.5 heavy % is by pipeline 15 discharge systems.First fraction is through after the extractive distillation, non-aromatics is discharged by pipeline 6, the rich solvent that contains benzene is discharged at the bottom of the tower and is delivered to solvent recovery tower 9 through pipeline 8, reclaim the cat head effluent and after condenser 11 coolings, enter basin 12, wherein light constituent is discharged by pipeline 14, benzaldehyde product is discharged by pipeline 13, and lean solvent is sent the recycle of extractive distillation cat head back to by pipeline 10 at the bottom of the tower.Each tower operational condition is with the extractive distillation part in the combination technology in the described flow process.
Adopting example 1 described cracking hydrogenated gasoline is raw material, is solvent with the tetramethylene sulfone, contains the solubility promoter o-Xylol of 6.0 heavy % in the solvent, reclaims single benzaldehyde product with extractive distillation technology shown in Figure 2.Separating effect sees Table 4.Listed file names with identically in the table 4, but do not contained the separating effect data of the Comparative Examples 2 of solubility promoter with this example process and operational condition.
As shown in Table 4, in the extractive distillation solvent, add solubility promoter after, the benzene content of lean solvent and raffinate oil in benzene content remarkable decline is all arranged, the benzene content in particularly raffinating oil drops to below the 1.0 heavy %.
Table 1
Table 2
| Component | Raw material is formed, heavy % | First fractional composition, heavy % | Second fractional composition, heavy % |
| Alkane C 5 C 6 C 7 C 8 | 0.01 0.73 0.90 0.46 | 0.02 1.41 0.89 0.01 | - - 1.06 1.09 |
| Naphthenic hydrocarbon C 5 C 6 C 7 C 8 | 1.50 3.96 2.76 1.22 | 2.90 7.46 1.62 - | - 0.25 4.61 2.89 |
| Aromatic hydrocarbons C 6 C 7 C 8 C 9 | 53.79 28.09 6.32 0.26 | 85.67 0.02 - - | 22.73 67.12 0.25 - |
| Amount to | 100.00 | 100.00 | 100.00 |
| Flow, kilogram/hour | 44466 | 23000 | 18577 |
| The tower name | Project | Example 1 | Example 2 | Comparative Examples 1 |
| Separation column | The raw material inlet temperature of stabilizer, ℃ first fraction tower exit temperature, ℃ second fraction tower exit temperature, ℃ | 80 78 92 | 80 78 92 | 80 78 92 |
| Solvent tower | The extractive distillation inlet amount, solubility promoter content in the kg/hr solvent ratio solvent, working pressure at the bottom of the heavy % tower, MPa lean solvent inlet temperature of stabilizer, ℃ | 23000 3.6 0 0.22 105 | 23000 3.6 4.5 0.22 105 | - - - - - |
| The extractive distillation solvent recovery tower | Trim the top of column compares tower top pressure, service temperature at the bottom of the MPa tower, working pressure at the bottom of ℃ tower, MPa | 0.8 0.045 178 0.06 | 0.8 0.045 175 0.08 | - - - - |
| Liquid liquid extraction tower | The extracting inlet amount, kg/hr solvent ratio backflow aromatic hydrocarbons is than lean solvent inlet temperature of stabilizer, ℃ lean solvent water content, heavy % cat head working pressure, MPa | 25132 3.5 0.6 80 0.8 0.7 | 24861 3.5 0.6 80 0.8 0.7 | 52237 3.3 0.6 80 0.8 0.7 |
| Stripping tower | The rich solvent inlet temperature of stabilizer, service temperature at the bottom of ℃ tower, working pressure at the bottom of ℃ tower, MPa | 110 175 0.30 | 110 175 0.28 | 108 175 0.33 |
| The extraction solvent recovery tower | Trim the top of column than water stripping than tower at the bottom of service temperature, working pressure at the bottom of ℃ tower, MPa | 0.5 0.023 175 0.075 | 0.5 0.023 175 0.075 | 0.5 0.023 175 0.075 |
Table 3
| Project | Example 1 | Example 2 | Comparative Examples 1 | |
| Benzaldehyde product is reclaimed in extractive distillation | Purity, heavy % is non-aromatic, ppm toluene, ppm sulphur, the ppm ctystallizing point, ℃ | 99.96 100 300 ＜2 ＞5.40 | 99.96 100 300 ＜2 ＞5.40 | 99.96 120 300 ＜2 ＞5.40 |
| The aromatic hydrocarbons that the extracting of liquid liquid is reclaimed | Purity, heavy % benzene content, heavy % toluene level, heavy % is non-aromatic, the ppm solvent, ppm | 99.95 26.84 73.12 400 ≤2 | 99.95 25.66 74.30 400 ≤2 | 99.95 65.69 34.24 500 ≤2 |
| The xylol product purity, heavy % toluene, ppm | 99.7 2000 | 99.7 2000 | 99.7 2000 | |
| Non-aromatics product aromatic hydrocarbons, heavy % solvent, ppm | 0.65 ＜1 | 0.64 ＜1 | 0.70 ＜1 | |
| The benzene yield, heavy % | 99.95 | 99.95 | 99.92 | |
| The toluene yield, heavy % | 99.50 | 99.50 | 99.51 | |
| The wastage in bulk or weight index *Steam, ton/ton raw material solvent, kg/ton raw material | 0.975 0.10～0.15 | 0.972 0.10～0.15 | 1.257 0.18～0.20 | |
*Refer to comprise the whole process processes expend of prefractionation, extracting, product rectifying.Table 4
| Project | Example 3 | Comparative Examples 2 | ||
| Solvent tower | Solvent recovery tower | Solvent tower | Solvent recovery tower | |
| The solvent ratio solvent is gone into the tower temperature, ℃ reflux ratio cat head working pressure, service temperature at the bottom of the MPa tower, ℃ | 4.0 85 0.1 0.1 108 | - 130 1.0 0.045 177 | 4.0 85 0.1 0.1 110 | - 130 1.0 0.045 177 |
| Benzene content in the lean solvent, heavy % | 0.20 | 1.9 | ||
| Solubility promoter content in the solvent, heavy % | 6.0 | 0.0 | ||
| Non-aromatic content in the aromatic hydrocarbons, heavy % | ≤0.01 | ≤0.01 | ||
| Sulphur content in the aromatic hydrocarbons, ppm | ＜2 | ＜2 | ||
| Benzene content in raffinating oil, heavy % | 0.55 | 4.30 | ||
Claims (9)
1, a kind of method of utilizing extractive distillation and liquid liquid extracting combination process to reclaim aromatic hydrocarbons from hydrocarbon mixture comprises the steps:
(1) hydrocarbon mixture is carried out prefractionation, obtaining benzene concentration is first fraction of 60.0～95.0 heavy % and second fraction that benzene concentration is 0.5～30.0 heavy %;
(2) first fraction is sent into solvent tower, obtain being rich in the solvent of benzene with arenes selectivity dissolution with solvents benzene wherein, this solvent that is rich in benzene is sent into the extractive distillation solvent recovery tower makes the arenes selectivity solvent separate with benzene, the lean solvent that obtains at the bottom of this recovery tower returns the extractive distillation cat head, benzaldehyde product is discharged by reclaiming cat head, and this goes on foot in the used arenes selectivity solvent not moisture;
(3) send into liquid liquid extraction tower after the mixing of raffinating oil that the extractive distillation cat head is discharged with described second fraction with in (2) step, obtain being rich in the solvent of aromatic hydrocarbons with arenes selectivity dissolution with solvents aromatic hydrocarbons wherein, the solvent that is rich in aromatic hydrocarbons is sent into stripping tower, the logistics rework solution liquid extraction tower that discharge on stripping tower top, the solvent that contains aromatic hydrocarbons that discharge the stripping tower bottom enters liquid liquid extraction solvent recovery tower, obtain pure aromatics at the recovery tower top, the lean solvent rework solution liquid extracting cat head of discharging at the bottom of the recovery tower contains the water of 0.3～1.0 weight % in the used arenes selectivity solvent of this step.
2, in accordance with the method for claim 1, it is characterized in that step (1) through after the prefractionation, benzene concentration is 70.0～95.0 heavy % in first fraction that obtains, and benzene concentration is 0.5～15.0 heavy % in second fraction.
3,, it is characterized in that described second fraction is the blending fraction of benzene and toluene according to claim 1 or 2 described methods.
4, in accordance with the method for claim 1, it is characterized in that containing in the used arenes selectivity solvent of step (2) C of 0.1～15.0 heavy %
8～C
10Aromatic hydrocarbons.
5, in accordance with the method for claim 4, it is characterized in that described aromatic hydrocarbons is selected from C
8～C
10In the aromatic hydrocarbons any one or their mixture, the content of aromatic hydrocarbons is 3.0～8.0 heavy % in the selective solvent.
6,, it is characterized in that the used arenes selectivity solvent phase in described step (2) and (3) together according to claim 1,2 or 4 described any one methods.
7, in accordance with the method for claim 6, it is characterized in that described arenes selectivity solvent is a tetramethylene sulfone.
8,, it is characterized in that aromaticity content is 60.0～98.0 heavy % in the described hydrocarbon mixture according to claim 1,2 or 4 described any one methods.
9,, it is characterized in that benzene content is 30.0～90.0 heavy % in the described hydrocarbon mixture according to claim 1,2 or 4 described any one methods.
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| CN112778245B (en) * | 2019-11-01 | 2022-09-20 | 中国石油化工股份有限公司 | Method and device for preparing maleic anhydride |
| CN113943586A (en) * | 2020-07-17 | 2022-01-18 | 中国石油天然气集团有限公司 | Method for removing aromatic hydrocarbon in straight-run naphtha |
| CN115193082B (en) * | 2022-09-16 | 2022-12-30 | 旭阳工程有限公司 | Crude benzene hydrofining separation process |
-
2000
- 2000-02-01 CN CN 00100477 patent/CN1125008C/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103305260A (en) * | 2012-03-16 | 2013-09-18 | 中国石油化工股份有限公司 | System and method for reducing viscosity of quenching oil of ethylene unit |
| CN103305260B (en) * | 2012-03-16 | 2015-10-07 | 中国石油化工股份有限公司 | A kind of system and method reducing ethylene unit quenching oil viscosity |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1262264A (en) | 2000-08-09 |
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