CN108997077B - Composite solvent and method for extracting and rectifying aromatic hydrocarbons from hydrocarbon mixture - Google Patents

Composite solvent and method for extracting and rectifying aromatic hydrocarbons from hydrocarbon mixture Download PDF

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CN108997077B
CN108997077B CN201710420938.2A CN201710420938A CN108997077B CN 108997077 B CN108997077 B CN 108997077B CN 201710420938 A CN201710420938 A CN 201710420938A CN 108997077 B CN108997077 B CN 108997077B
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tower
aromatic hydrocarbons
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hydrocarbon mixture
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高思亮
田龙胜
唐文成
赵明
杨楠
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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Abstract

一种从烃类混合物中萃取精馏分离芳烃的复合溶剂,包括40‑80质量%的环丁砜和20‑60质量%的助溶剂,所述的助溶剂为具有式(Ⅰ)结构的砜类衍生物,

Figure DDA0001314907640000011
式(Ⅰ)中,R1和R2分别选自C1~C4的烷基、环烷基或芳基。所述的复合溶剂性质稳定,无腐蚀性,对芳烃具有较高的选择性,并且在使用过程中易于调控,可降低萃取精馏操作的物耗和能耗。A composite solvent for extracting, rectifying and separating aromatic hydrocarbons from a hydrocarbon mixture, comprising 40-80 mass % sulfolane and 20-60 mass % co-solvent, wherein the co-solvent is a sulfone derivative having the structure of formula (I) things,
Figure DDA0001314907640000011
In formula (I), R 1 and R 2 are independently selected from C 1 -C 4 alkyl, cycloalkyl or aryl. The composite solvent has stable properties, is non-corrosive, has high selectivity to aromatic hydrocarbons, is easy to control during use, and can reduce material consumption and energy consumption of extractive distillation operations.

Description

从烃类混合物中萃取精馏分离芳烃的复合溶剂及方法Composite solvent and method for extracting and rectifying aromatic hydrocarbons from hydrocarbon mixture

技术领域technical field

本发明为一种从石油流体中分离芳烃的复合溶剂,具体地说,是一种利用萃取精馏从石油烃类原料中分离高纯度芳烃所用的复合溶剂及其应用方法。The invention relates to a composite solvent for separating aromatic hydrocarbons from petroleum fluids, specifically, a composite solvent for separating high-purity aromatic hydrocarbons from petroleum hydrocarbon raw materials by extractive rectification and an application method thereof.

背景技术Background technique

从催化重整汽油和加氢裂解汽油等烃类混合物中分离芳烃主要有两类工艺。一类是液液抽提,其本质为液液萃取-萃取精馏的联合过程,适合从宽馏分原料中分离芳烃,所使用的溶剂为甘醇类溶剂、环丁砜等。液液抽提工艺能以较高收率获得高纯度苯、甲苯、二甲苯(BTX)产品,但原料中芳烃含量不能太高,否则抽提塔不易操作。另一类为抽提蒸馏(ED)工艺,是利用溶剂对烃类各组分相对挥发度影响的不同进而从原料中分离芳烃的方法。相比之下,抽提蒸馏工艺能耗低、流程简单,较适于处理高芳烃含量、窄馏分的原料,所用的溶剂一般为甘醇类、环丁砜、N-甲基吡咯烷酮、N-甲酰基吗啉等,得到的产品为苯,或者苯和甲苯。There are two main processes for the separation of aromatics from hydrocarbon mixtures such as catalytic reformed gasoline and hydrocracking gasoline. One is liquid-liquid extraction, which is essentially a combined process of liquid-liquid extraction and extractive rectification. It is suitable for separating aromatic hydrocarbons from wide-cut raw materials. The solvents used are glycol solvents, sulfolane, etc. The liquid-liquid extraction process can obtain high-purity benzene, toluene, xylene (BTX) products with high yields, but the content of aromatic hydrocarbons in the raw materials should not be too high, otherwise the extraction tower will not be easy to operate. The other is the Extractive Distillation (ED) process, which is a method of separating aromatic hydrocarbons from raw materials by utilizing the different effects of solvents on the relative volatility of each component of hydrocarbons. In contrast, the extractive distillation process has low energy consumption and simple process, and is more suitable for processing raw materials with high aromatic content and narrow fractions. The solvents used are generally glycols, sulfolane, N-methylpyrrolidone, N-formyl Morpholine, etc., the resulting product is benzene, or benzene and toluene.

未能使用ED工艺分离提纯苯、甲苯、二甲苯的原因在于目前所用溶剂的选择性和溶解性难于兼顾。裂解加氢汽油C6-C8馏分中,沸点最低的芳烃为苯 (80.1℃),沸点最高的环烷烃为乙基环己烷(131.8℃)。在ED塔中要实现苯存在于塔釜富溶剂中,而乙基环己烷被蒸至塔顶,需要溶剂与苯的相互作用很强,而对乙基环己烷之类的非芳则较为排斥。而具有高选择性的溶剂对非芳烃的溶解性往往较差,在塔的上部,尤其是溶剂进料位置与原料进料位置之间容易分相,从而导致ED塔操作困难。The reason why benzene, toluene and xylene cannot be separated and purified by ED process is that it is difficult to balance the selectivity and solubility of the currently used solvents. In the C 6 -C 8 fraction of cracked hydrogenated gasoline, the aromatic hydrocarbon with the lowest boiling point was benzene (80.1°C), and the cycloalkane with the highest boiling point was ethylcyclohexane (131.8°C). In the ED tower, to realize that benzene exists in the rich solvent of the tower kettle, and ethyl cyclohexane is distilled to the top of the tower, the interaction between the solvent and benzene is required to be strong, and the non-aromatic substances such as p-ethyl cyclohexane are more exclusive. However, solvents with high selectivity tend to have poor solubility for non-aromatic hydrocarbons, and are prone to phase separation in the upper part of the tower, especially between the solvent feeding position and the raw material feeding position, which makes the ED tower difficult to operate.

在高选择性溶剂中加入至少一种助溶剂有可能提高溶剂的选择性并提高主溶剂的整体效率。The addition of at least one co-solvent to the highly selective solvent has the potential to increase the selectivity of the solvent and increase the overall efficiency of the primary solvent.

CN1430660A公开了一种从石油液体中纯化芳烃的方法,以环丁砜为主溶剂,助溶剂选自3-甲基环丁砜、N-甲基-2吡咯烷酮(NMP)、苯乙酮、异佛尔酮和吗啉中的一种,将该复合溶剂用于分离苯/正庚烷的体系,得到了优于纯环丁砜的效果。CN1430660A discloses a method for purifying aromatic hydrocarbons from petroleum liquid. The main solvent is sulfolane, and the cosolvent is selected from 3-methylsulfolane, N-methyl-2-pyrrolidone (NMP), acetophenone, isophorone and A kind of morpholine, the composite solvent is used in the system of separating benzene/n-heptane, and the effect is better than that of pure sulfolane.

CN104058916A公开了一类萃取精馏分离芳烃的吗啉类混合溶剂及其使用方法,所述混合溶剂为N-甲酰吗啉和N-乙酰吗啉,分离对象为石油苯C6-C8馏分,得到芳烃产品中仍含有浓度超过1mg/L的溶剂,实际应用中后续仍需脱氮处理。CN104058916A discloses a kind of morpholine mixed solvent for extracting and rectifying aromatic hydrocarbons and its use method, the mixed solvent is N-formyl morpholine and N-acetylmorpholine, and the separation object is petroleum benzene C 6 -C 8 fraction , the obtained aromatic hydrocarbon product still contains a solvent with a concentration of more than 1 mg/L, and subsequent denitrification treatment is still required in practical application.

CN1272408C公开了一种萃取精馏分离芳烃的复合溶剂,主溶剂为砜类化合物、甘醇类化合物,N-甲酰基吗啉或N-甲基吡咯烷酮;助溶剂为具有两个苯环的烃类化合物。使用该复合溶剂分离重整脱戊烷油C6-C7馏分,能够以高收率得到高纯度的苯/甲苯混合芳烃产品。CN1272408C discloses a composite solvent for extracting and rectifying aromatic hydrocarbons. The main solvent is sulfone compounds, glycol compounds, N-formyl morpholine or N-methylpyrrolidone; the auxiliary solvent is hydrocarbons with two benzene rings compound. By using the composite solvent to separate and reform the C 6 -C 7 fractions of the depentanized oil, a high-purity benzene/toluene mixed aromatic product can be obtained with a high yield.

发明内容SUMMARY OF THE INVENTION

本发明的目的是提供一种从烃类混合物中萃取精馏分离芳烃的复合溶剂及方法,所述的复合溶剂性质稳定,无腐蚀性,对芳烃具有较高的选择性,并且在使用过程中易于调控,可降低萃取精馏操作的物耗和能耗。The object of the present invention is to provide a composite solvent and method for extracting and rectifying aromatic hydrocarbons from hydrocarbon mixtures. It is easy to control and can reduce the material consumption and energy consumption of extractive distillation operation.

本发明提供的从烃类混合物中萃取精馏芳烃的复合溶剂,包括40-80质量%的环丁砜和20-60质量%的助溶剂,所述的助溶剂为具有式(Ⅰ)结构的砜类衍生物,The composite solvent for extracting and rectifying aromatic hydrocarbons from hydrocarbon mixtures provided by the present invention comprises 40-80 mass % of sulfolane and 20-60 mass % of co-solvent, and the co-solvent is a sulfone having the structure of formula (I). derivative,

Figure BDA0001314907620000021
Figure BDA0001314907620000021

式(Ⅰ)中,R1和R2分别选自C1~C4的烷基、环烷基或芳基。In formula (I), R 1 and R 2 are independently selected from C 1 -C 4 alkyl, cycloalkyl or aryl.

本发明方法在环丁砜溶剂中加入适量式(Ⅰ)所示的有两个取代基砜类衍生物作为助溶剂,在萃取精馏分离含有环烷烃的原料中的芳烃时,可有效降低溶剂比,节省能耗,并且分离得到的产品不含氮,硫含量<1mg/L,无需后续精制处理。The method of the invention adds an appropriate amount of sulfone derivatives represented by formula (I) into the sulfolane solvent as a co-solvent, and can effectively reduce the solvent ratio when extracting and rectifying the aromatic hydrocarbons in the raw material containing naphthenes. Energy consumption is saved, and the separated product does not contain nitrogen, the sulfur content is less than 1mg/L, and no subsequent refining treatment is required.

附图说明Description of drawings

图1为本发明使用复合溶剂进行萃取精馏的流程示意图。FIG. 1 is a schematic flow diagram of the present invention using a composite solvent for extractive distillation.

具体实施方式Detailed ways

本发明提供的复合溶剂包括主溶剂—环丁砜和助溶剂—有两个取代基的砜类衍生物,主溶剂决定复合溶剂的主要性质,助溶剂与主溶剂协同作用,提高溶剂对芳烃的选择性,并增加对非芳烃的溶解性,改善气液传质性能。本发明所述的复合溶剂沸点高、性质稳定,且对原料溶解性较好,在保证高选择性的基础上,萃取精馏的整体效率比单一溶剂好,能够改善分离所得芳烃的质量,提高芳烃收率。The composite solvent provided by the invention includes a main solvent—sulfolane and a cosolvent—a sulfone derivative with two substituents. The main solvent determines the main properties of the composite solvent, and the cosolvent and the main solvent act synergistically to improve the selectivity of the solvent to aromatic hydrocarbons. , and increase the solubility of non-aromatic hydrocarbons and improve gas-liquid mass transfer performance. The composite solvent of the invention has high boiling point, stable properties, and good solubility for raw materials. On the basis of ensuring high selectivity, the overall efficiency of extractive distillation is better than that of a single solvent, which can improve the quality of aromatic hydrocarbons obtained by separation, and improve the Aromatic yield.

本发明所述的复合溶剂优选包括45-78质量%的环丁砜和22-55质量%的助溶剂。The composite solvent of the present invention preferably comprises 45-78 mass % of sulfolane and 22-55 mass % of cosolvent.

所述的助溶剂为式(Ⅰ)所述的具有两个取代基的砜类衍生物,其中的取代基R1和R2可相同,也可不同,分别选自C1~C4的烷基、环烷基或芳基。所述的环烷基优选C4~C6的环烷基,所述的芳基优选苯基。The co-solvent is a sulfone derivative with two substituents described in formula (I), wherein the substituents R 1 and R 2 may be the same or different, and are respectively selected from C 1 -C 4 alkanes radical, cycloalkyl or aryl. The cycloalkyl group is preferably a C 4 -C 6 cycloalkyl group, and the aryl group is preferably a phenyl group.

优选地,所述的助溶剂中的R1和R2不同,R1和R2分别选自C1~C4的烷基,所述的C1~C4的烷基可为甲基、乙基、丙基、异丙基、丁基、异丁基。Preferably, R 1 and R 2 in the co-solvent are different, R 1 and R 2 are respectively selected from C 1 -C 4 alkyl groups, and the C 1 -C 4 alkyl groups may be methyl, Ethyl, propyl, isopropyl, butyl, isobutyl.

所述的助溶剂中的R1和R2不同的情况还可以为R1选自C1~C4的烷基,R2选自环己烷基或苯基。In the case where R 1 and R 2 in the co-solvent are different, R 1 can also be selected from C 1 -C 4 alkyl groups, and R 2 is selected from cyclohexyl or phenyl.

本发明所述的的助溶剂可为:甲基乙基砜、甲基异丙基砜、乙基异丙基砜、甲基环戊基砜、甲基苯基砜、乙基苯基砜、二苯基砜。The auxiliary solvent of the present invention can be: methyl ethyl sulfone, methyl isopropyl sulfone, ethyl isopropyl sulfone, methyl cyclopentyl sulfone, methyl phenyl sulfone, ethyl phenyl sulfone, Diphenylsulfone.

本发明提供的从烃类混合物中萃取精馏分离芳烃的方法,包括将烃类混合物引入萃取精馏塔的中部,本发明所述的复合溶剂引入萃取精馏塔的上部,经过萃取精馏,非芳烃从塔顶排出,一部分作为塔顶回流返回萃取精馏塔,另一部分排出系统,富含芳烃的富溶剂从萃取精馏塔塔底排出进入溶剂回收塔中部,芳烃从塔顶排出,贫溶剂从塔底排出后返回萃取精馏塔循环使用。The method for extracting and rectifying aromatic hydrocarbons from a hydrocarbon mixture provided by the present invention includes introducing the hydrocarbon mixture into the middle of the extractive rectification column, introducing the composite solvent of the present invention into the upper part of the extractive rectification column, and after extractive rectification, Non-aromatic hydrocarbons are discharged from the top of the tower, part of which is returned to the extractive rectification tower as a reflux at the top of the tower, and the other part is discharged from the system. The rich solvent rich in aromatic hydrocarbons is discharged from the bottom of the extractive rectification tower and enters the middle of the solvent recovery tower. The solvent is discharged from the bottom of the column and returned to the extractive distillation column for recycling.

上述方法中,进入萃取精馏塔的复合溶剂与烃类混合物原料的质量比,即溶剂比优选1-20、更优选3-10,萃取精馏塔的理论板数为30-80,回流比为0.2-5,复合溶剂入塔温度优选70-90℃,塔底温度优选120-150℃,塔顶压力优选 0.1-0.3MPa。In the above-mentioned method, the mass ratio of the composite solvent entering the extractive distillation column and the hydrocarbon mixture raw material, i.e. the solvent ratio is preferably 1-20, more preferably 3-10, the theoretical plate number of the extractive distillation column is 30-80, and the reflux ratio is 30-80. is 0.2-5, the temperature of the composite solvent entering the tower is preferably 70-90°C, the temperature at the bottom of the tower is preferably 120-150°C, and the pressure at the top of the tower is preferably 0.1-0.3MPa.

所述溶剂回收塔的理论塔板数优选5-30,回流比优选0.5-2.0,塔顶压力优选0.01-0.05MPa,塔底温度优选155-190℃。The number of theoretical plates of the solvent recovery column is preferably 5-30, the reflux ratio is preferably 0.5-2.0, the pressure at the top of the column is preferably 0.01-0.05MPa, and the temperature at the bottom of the column is preferably 155-190°C.

本发明所述的烃类混合物为裂解加氢汽油C6-C8馏分、凝析油、重整生成油C6-C8馏分或煤焦油C6馏分,其中的芳烃含量优选为20-88质量%。The hydrocarbon mixture described in the present invention is a C 6 -C 8 fraction of cracked hydrogenated gasoline, condensate, a C 6 -C 8 fraction of reformed oil or a C 6 fraction of coal tar, wherein the aromatic content is preferably 20-88 quality%.

本发明提供的复合溶剂和萃取精馏方法尤其适合从裂解加氢汽油C6-C8馏分中分离回收苯、甲苯和二甲苯。The composite solvent and the extractive distillation method provided by the invention are especially suitable for separating and recovering benzene, toluene and xylene from the C 6 -C 8 fraction of cracked hydrogenated gasoline.

本发明中,溶剂对被分离的两组分的选择性用相对挥发度(α)表征,其定义为:In the present invention, the selectivity of a solvent to the two components to be separated is characterized by relative volatility (α), which is defined as:

α=(Y2/X2)/(Y1/X1) (1)α=(Y 2 /X 2 )/(Y 1 /X 1 ) (1)

式(1)中,X1和X2分别表示组分1和组分2在液相中的质量分数,Y1和Y2分别表示组分1和组分2在气相中的质量分数。α值越大,表明抽提蒸馏过程越容易,可用较少的蒸馏步骤、较少的回流量得到纯度较高的产品。In formula (1), X 1 and X 2 represent the mass fractions of component 1 and component 2 in the liquid phase, respectively, and Y 1 and Y 2 represent the mass fractions of component 1 and component 2 in the gas phase, respectively. The larger the value of α, the easier the extractive distillation process is, and the product with higher purity can be obtained with less distillation steps and less reflux.

下面结合附图进一步说明本发明。The present invention will be further described below in conjunction with the accompanying drawings.

图1中,烃类混合物由管线1进入换热器101,与贫溶剂换热后进入萃取精馏塔102的中部,复合溶剂由管线2从上部进入萃取精馏塔102。二者逆流接触进行萃取精馏,非芳烃从萃取精馏塔塔顶排出,进入冷凝器103冷凝,一部分由管线4回流至萃取精馏塔102,其余作为非芳产品由管线3排出装置。富含芳烃的富溶剂由萃取精馏塔的塔底排出,经管线5进入溶剂回收塔104,经减压蒸馏后,芳烃由塔顶排出,进入冷凝器105冷凝,一部分由管线6返回至溶剂回收塔104,其余经管线7作为芳烃产品采出。贫溶剂由溶剂回收塔塔底排出,其中的一小部分由管线8送去再生装置,其余由管线9返回至萃取精馏塔102循环利用。所述萃取精馏塔和溶剂回收塔底部的加热源为再沸器,即将塔底排出物中的一部经再沸器加热升至所需温度后,送入塔底。In FIG. 1 , the hydrocarbon mixture enters the heat exchanger 101 through line 1, and enters the middle of the extractive rectification column 102 after heat exchange with the lean solvent, and the composite solvent enters the extractive rectification column 102 from the upper part of the line 2. The two are in countercurrent contact for extractive rectification, the non-aromatic hydrocarbons are discharged from the top of the extractive rectification tower, enter the condenser 103 for condensation, a part is refluxed to the extractive rectification tower 102 by pipeline 4, and the rest are discharged from the pipeline 3 as non-aromatic products. The rich solvent rich in aromatic hydrocarbons is discharged from the bottom of the extractive rectification tower, and enters the solvent recovery tower 104 through pipeline 5. After distillation under reduced pressure, the aromatic hydrocarbons are discharged from the top of the tower, enter the condenser 105 for condensation, and a part is returned to the solvent by pipeline 6. Column 104 is recovered, and the rest is recovered via line 7 as an aromatic product. The lean solvent is discharged from the bottom of the solvent recovery tower, a small part of which is sent to the regeneration device through the pipeline 8, and the rest is returned to the extractive distillation column 102 through the pipeline 9 for recycling. The heating source at the bottom of the extractive rectification column and the solvent recovery column is the reboiler, that is, a part of the effluent at the bottom of the column is heated to the required temperature by the reboiler, and then sent to the bottom of the column.

下面通过实例进一步说明本发明,但本发明并不限于此。The present invention is further illustrated by examples below, but the present invention is not limited thereto.

实例1Example 1

本实例考察以甲乙砜为助溶剂的复合溶剂对芳烃/非芳烃的分离性能。In this example, the separation performance of aromatic hydrocarbons/non-aromatic hydrocarbons by a composite solvent with methyl ethyl sulfone as a co-solvent was investigated.

将90质量%的苯和10质量%的乙基环己烷混合作为原料,加至配好的有 不同含量的甲乙砜的复合溶剂中,复合溶剂与原料的质量比,即溶剂比为3.3。90 mass % of benzene and 10 mass % of ethylcyclohexane were mixed as raw materials, and added to the mixed solvent with different contents of methyl ethyl sulfone. The mass ratio of the composite solvent to the raw material, i.e., the solvent ratio, was 3.3.

将全部混合物震荡摇匀,升温至100℃,静置30min,用气相色谱分析其 气相组成,由式(1)计算乙基环己烷对苯的相对挥发度α,其中乙基环己烷为 组分2,苯为组分1,结果见表1。The whole mixture was shaken and shaken, heated to 100° C., allowed to stand for 30 min, and its gas phase composition was analyzed by gas chromatography, and the relative volatility α of ethylcyclohexane to benzene was calculated by formula (1), where ethylcyclohexane was Component 2, benzene is the component 1, and the results are shown in Table 1.

表1Table 1

Figure RE-GDA0002864173740000011
Figure RE-GDA0002864173740000011

从表1可知,不加溶剂时乙基环己烷对苯的相对挥发度仅为0.14,远小于 1,这是由于乙基环己烷的沸点为131.8℃,远高于苯。纯环丁砜在溶剂比为3.3 的条件下,能将相对挥发度提高至1.426,即可用抽提蒸馏将二者分离。含10 质量%的甲乙砜的复合溶剂的相对挥发度较之环丁砜略有降低,但随着复合溶 剂中甲乙砜含量的增加,相对挥发度提高,最高可至1.565,较纯环丁砜提高约 10%。It can be seen from Table 1 that the relative volatility of ethylcyclohexane to benzene is only 0.14 when no solvent is added, which is far less than 1. This is because the boiling point of ethylcyclohexane is 131.8 °C, which is much higher than that of benzene. The relative volatility of pure sulfolane can be increased to 1.426 when the solvent ratio is 3.3, and the two can be separated by extractive distillation. The relative volatility of the composite solvent containing 10% by mass of methyl ethyl sulfone is slightly lower than that of sulfolane, but with the increase of the content of methyl ethyl sulfone in the composite solvent, the relative volatility increases, up to 1.565, which is about 10% higher than that of pure sulfolane .

实例2Example 2

本实例考察以甲基异丙基砜为助溶剂的复合溶剂对芳烃/非芳烃的分离性 能。This example investigates the separation performance of a complex solvent with methyl isopropyl sulfone as a co-solvent for aromatics/non-aromatics.

按实例1的方法测定复合溶剂的相对挥发度,不同的是复合溶剂中的助溶剂为甲基异丙基砜。由式(1)计算的各溶剂的乙基环己烷对苯的相对挥发度α见表2。The relative volatility of the composite solvent was measured according to the method of Example 1, except that the co-solvent in the composite solvent was methyl isopropyl sulfone. The relative volatility α of ethylcyclohexane to benzene of each solvent calculated by formula (1) is shown in Table 2.

表2Table 2

Figure BDA0001314907620000051
Figure BDA0001314907620000051

从表2可知,在环丁砜中添加甲基异丙基砜为助溶剂,也可有效改善乙基环己烷对苯的相对挥发度α。It can be seen from Table 2 that adding methyl isopropyl sulfone to sulfolane as a cosolvent can also effectively improve the relative volatility α of ethylcyclohexane to benzene.

实例3Example 3

本实例考察以甲基苯基砜为助溶剂的复合溶剂对芳烃/非芳烃的分离性能。This example investigates the separation performance of the complex solvent using methyl phenyl sulfone as a co-solvent for aromatics/non-aromatics.

按实例1的方法测定复合溶剂的相对挥发度,不同的是复合溶剂中的助溶剂为甲基苯基砜。由式(1)计算的各溶剂的乙基环己烷对苯的相对挥发度α见表3。The relative volatility of the composite solvent was determined according to the method of Example 1, except that the co-solvent in the composite solvent was methyl phenyl sulfone. The relative volatility α of ethylcyclohexane to benzene of each solvent calculated by formula (1) is shown in Table 3.

表3table 3

Figure BDA0001314907620000052
Figure BDA0001314907620000052

从表3中可以看出,在环丁砜中添加甲基苯基砜为助溶剂,也可有效改善乙基环己烷对苯的相对挥发度α。It can be seen from Table 3 that adding methyl phenyl sulfone as a co-solvent to sulfolane can also effectively improve the relative volatility α of ethyl cyclohexane to benzene.

对比例1Comparative Example 1

本对比例考察已公开的助溶剂对苯/乙基环己烷体系相对挥发度的影响。This comparative example examines the effect of the disclosed co-solvents on the relative volatility of the benzene/ethylcyclohexane system.

按实例1的方法,以90质量%的苯和10质量%的乙基环己烷混合物为原料,评价不同溶剂比时,在环丁砜中加入不同助溶剂及助溶剂含量对乙基环己烷/苯相对挥发度的影响,结果见表4,其中NMP为N-甲基吡咯烷酮。According to the method of Example 1, using 90 mass% benzene and 10 mass% ethylcyclohexane mixture as raw materials, when evaluating different solvent ratios, adding different cosolvents and cosolvent content p-ethylcyclohexane/ The effect of the relative volatility of benzene, the results are shown in Table 4, wherein NMP is N-methylpyrrolidone.

表4Table 4

Figure BDA0001314907620000061
Figure BDA0001314907620000061

从表4可知,在分离苯/乙基环己烷体系过程中,在环丁砜中加入3-甲基环丁砜或NMP为助溶剂,在溶剂比相同的条件下,未使复合溶剂的选择性高于纯环丁砜;并且随着助溶剂加入量的增加,复合溶剂选择性下降。As can be seen from Table 4, in the process of separating the benzene/ethylcyclohexane system, adding 3-methyl sulfolane or NMP to sulfolane as a co-solvent, under the conditions of the same solvent ratio, the selectivity of the composite solvent is not higher than that of the composite solvent. pure sulfolane; and with the increase of the amount of co-solvent added, the selectivity of the composite solvent decreases.

实例4Example 4

以裂解加氢汽油C6-C8馏分为原料,其组成见表5,按图1的流程萃取精馏分离其中的烷烃和芳烃,使用的复合溶剂中含50质量%的甲乙砜,50质量%的环丁砜,萃取精馏塔、溶剂回收塔的操作条件见表6,分离结果见表7。The C 6 -C 8 fraction of cracked hydrogenated gasoline is used as the raw material, and its composition is shown in Table 5. The alkanes and aromatic hydrocarbons are separated by extraction and rectification according to the process shown in Figure 1. The composite solvent used contains 50% by mass of methyl ethyl sulfone, 50% by mass % sulfolane, the operating conditions of the extractive distillation tower and the solvent recovery tower are shown in Table 6, and the separation results are shown in Table 7.

表5table 5

Figure BDA0001314907620000071
Figure BDA0001314907620000071

表6Table 6

Figure BDA0001314907620000072
Figure BDA0001314907620000072

表7Table 7

项目project 实例4Example 4 对比例2Comparative Example 2 混合芳烃产品Mixed Aromatic Products 纯度,质量%Purity, mass % 99.9099.90 99.6599.65 收率,质量%Yield, mass % 99.999.9 99.599.5 非芳烃non-aromatic hydrocarbons 助溶剂含量,ppmCosolvent content, ppm 2525 3030 芳烃含量,质量%Aromatic content, mass % 0.70.7 2.5 2.5

对比例2Comparative Example 2

采用90质量%的环丁砜和10质量%的3-甲基环丁砜组成的复合溶剂为萃取精馏溶剂,按实例4方法萃取精馏分离裂解加氢汽油C6-C8馏分中的芳烃和非芳烃,萃取精馏塔、溶剂回收塔的操作条件见表6,结果见表7。The composite solvent composed of 90% by mass of sulfolane and 10% by mass of 3-methylsulfolane was used as extractive distillation solvent, and the aromatic hydrocarbons and non-aromatic hydrocarbons in the C 6 -C 8 fractions of cracked hydrogenated gasoline were separated by extractive distillation according to the method of Example 4. , the operating conditions of the extractive rectification tower and the solvent recovery tower are shown in Table 6, and the results are shown in Table 7.

结果表明,本发明所述的复合溶剂较之对比例2的复合溶剂,在溶剂比较小及其它操作条件基本相同的情况下,分离所得的混合芳烃产品纯度、收率均较高。The results show that, compared with the composite solvent of Comparative Example 2, the composite solvent of the present invention has higher purity and yield of the separated mixed aromatic products under the condition that the solvent is relatively small and other operating conditions are basically the same.

Claims (8)

1.一种从烃类混合物中萃取精馏分离芳烃的复合溶剂,由40-50质量%的环丁砜和50-60质量%的助溶剂组成,所述的助溶剂为具有式(Ⅰ)结构的砜类衍生物,1. a composite solvent for extracting and rectifying aromatic hydrocarbons from a hydrocarbon mixture, consisting of 40-50 mass % sulfolane and 50-60 mass % co-solvent, and described co-solvent has the structure of formula (I) sulfone derivatives,
Figure FDF0000014825260000011
Figure FDF0000014825260000011
式(Ⅰ)中,R1和R2不同,分别选自C1~C4的烷基、C4~C6的环烷基或苯基,所述的烃类混合物为裂解加氢汽油C6-C8馏分、凝析油或重整生成油C6-C8馏分。In formula (I), R 1 and R 2 are different, and are respectively selected from C 1 -C 4 alkyl, C 4 -C 6 cycloalkyl or phenyl, and the hydrocarbon mixture is cracked hydrogenated gasoline C 6 - C8 fraction, condensate or reformed oil C6 - C8 fraction.
2.按照权利要求1所述的复合溶剂,其特征在于所述的复合溶剂由45-50质量%的环丁砜和50-55质量%的助溶剂组成。2 . The composite solvent according to claim 1 , wherein the composite solvent is composed of 45-50 mass % sulfolane and 50-55 mass % cosolvent. 3 . 3.按照权利要求1或2所述的复合溶剂,其特征在于所述助溶剂中的R1和R2分别选自C1~C4的烷基。3 . The composite solvent according to claim 1 or 2 , wherein R 1 and R 2 in the co-solvent are respectively selected from C 1 -C 4 alkyl groups. 4 . 4.按照权利要求1或2所述的复合溶剂,其特征在于所述助溶剂中的R1选自C1~C4的烷基,R2选自环己烷基或苯基。4 . The composite solvent according to claim 1 or 2 , wherein R 1 in the co-solvent is selected from C 1 -C 4 alkyl groups, and R 2 is selected from cyclohexane or phenyl. 5 . 5.一种从烃类混合物中萃取精馏分离芳烃的方法,包括将烃类混合物引入萃取精馏塔的中部,权利要求1所述的复合溶剂引入萃取精馏塔的上部,经过萃取精馏,非芳烃从塔顶排出,一部分作为塔顶回流返回萃取精馏塔,另一部分排出系统,富含芳烃的富溶剂从萃取精馏塔塔底排出进入溶剂回收塔中部,芳烃从塔顶排出,贫溶剂从塔底排出后返回萃取精馏塔循环使用,所述的烃类混合物为裂解加氢汽油C6-C8馏分、凝析油或重整生成油C6-C8馏分。5. a method for extracting and rectifying and separating aromatic hydrocarbons from hydrocarbon mixture, comprising introducing the hydrocarbon mixture into the middle of the extractive rectification tower, the composite solvent of claim 1 being introduced into the top of the extractive rectification tower, and through the extractive rectification column. , the non-aromatic hydrocarbons are discharged from the top of the tower, a part is returned to the extractive rectification tower as the top of the tower, and the other part is discharged from the system. The rich solvent rich in aromatics is discharged from the bottom of the extractive rectification tower and enters the middle of the solvent recovery tower, and the aromatics are discharged from the top of the tower. The lean solvent is discharged from the bottom of the tower and returned to the extractive distillation tower for recycling, and the hydrocarbon mixture is a C 6 -C 8 fraction of cracked hydrogenated gasoline, a condensate or a C 6 -C 8 fraction of reformed oil. 6.按照权利要求5所述的方法,其特征在于进入萃取精馏塔的复合溶剂与烃类混合物原料的质量比为1-20,萃取精馏塔的理论板数为30-80,回流比为0.2-5,复合溶剂入塔温度为70-90℃,塔底温度为120-150℃,塔顶压力为0.1-0.3MPa。6. according to the described method of claim 5, it is characterized in that the mass ratio of the composite solvent entering the extractive distillation column and the hydrocarbon mixture raw material is 1-20, and the theoretical plate number of the extractive distillation column is 30-80, and the reflux ratio is 0.2-5, the temperature of the composite solvent entering the tower is 70-90°C, the temperature at the bottom of the tower is 120-150°C, and the pressure at the top of the tower is 0.1-0.3MPa. 7.按照权利要求5所述的方法,其特征在于溶剂回收塔的理论塔板数为20-50,回流比为0.5-2.0,塔顶压力为0.01-0.05MPa,塔底温度为155-190℃。7. according to the method described in claim 5, it is characterized in that the theoretical plate number of solvent recovery tower is 20-50, and reflux ratio is 0.5-2.0, tower top pressure is 0.01-0.05MPa, and tower bottom temperature is 155-190 °C. 8.按照权利要求5所述的方法,其特征在于烃类混合物中芳烃含量为20-88质量%。8. The method according to claim 5, wherein the content of aromatic hydrocarbons in the hydrocarbon mixture is 20-88% by mass.
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