CN105273742B - Method for solid phase extraction separating of components in heavy oil - Google Patents

Abstract

A method for separating various components of heavy oil by solid phase extraction, comprising diluting the heavy oil and adding it to a stationary phase, then sequentially washing the stationary phase with C ₅ -C ₆ alkanes to obtain saturated hydrocarbon components, and using aromatic hydrocarbons and C ₅ -C ₆ Flush the stationary phase with a solvent with an alkane volume ratio of 1:15-25 to obtain light aromatic components, and wash the stationary phase with a solvent with a volume ratio of aromatic hydrocarbons and C ₅ to C ₆ alkanes at a volume ratio of 1:3-5 to obtain medium aromatic components. Rinse the stationary phase to obtain heavy aromatic components, wash the stationary phase with a solvent with an aromatic hydrocarbon and monohydric alcohol volume ratio of 1:0.8 to 1.5 to obtain colloidal components, the stationary phase is alumina loaded with silver ions, and the loaded silver ions It accounts for 0.5-12% of the mass of alumina. The method uses aluminum oxide loaded with silver ions as the stationary phase, which can separate hydrocarbons with different polar components in heavy oil. The immobilized phase has large sample processing capacity, high separation efficiency, and the loaded silver ions are not easy to be eluted.

Description

A method for solid-phase extraction and separation of components of heavy oil

technical field

The invention relates to a method for separating various hydrocarbon components in heavy oil, specifically, a method for separating hydrocarbon components with different structures in heavy oil by solid phase extraction.

Background technique

Heavy oil is the main raw material for secondary processing processes such as catalytic cracking, hydrofining, hydrocracking and coking, and the processing level of heavy oil is an important factor affecting the economic benefits of refineries. Due to the complex structure and composition of heavy oil, even when the overall properties such as H/C ratio and average molecular weight are similar, the detailed hydrocarbon composition and carbon number distribution of heavy oil are very different. These differences will cause differences in transformation laws due to different chemical reactions. Therefore, it is necessary to select the most matching secondary processing technology based on the understanding of its approach to the excimer level and the research on the reactivity of different polar components. Improve the effective utilization rate and processing technology level of heavy oil.

Saturated hydrocarbons in heavy oil are good raw materials for secondary processing, but the secondary processing performance of aromatic hydrocarbons and heteroatom compounds is poor. At present, the research on aromatic hydrocarbons in heavy oil, especially polycyclic aromatic hydrocarbons, has attracted widespread attention. However, high-purity samples are required for both analytical testing and processing performance evaluation, which requires the separation of components in heavy oil according to polarity, so two requirements are put forward for the separation process: (1) High separation efficiency , can separate high-purity samples to meet the needs of subsequent analysis and detection and reaction mechanism research; (2) the sample processing volume is large, and can quickly separate the sample amount that can meet the needs of subsequent reactions and evaluation experiments; (3) can The aromatic components are further separated according to polarity to realize the enrichment of single-ring aromatics, double-ring aromatics and polycyclic aromatics.

The components of heavy oil are separated according to polarity, mainly according to the composition of hydrocarbons. For example, the separation method for determining the latent content of lubricating oil by double adsorbent method is to separate the dewaxed lubricating oil fraction into saturated hydrocarbons, light aromatics, Four components of medium aromatics and heavy aromatics. The basic process is to dewax ketone and benzene first, then use alumina (γ-Al ₂ O ₃ ) and silica gel double adsorbents as stationary phases for column chromatography separation, and use petroleum ether, petroleum ether-benzene, benzene -Ethanol (1:1) is used as the solvent to wash out the four components of saturated hydrocarbons, light aromatics, medium aromatics and heavy aromatics in sequence (edited by Yang Cuiding et al. Analytical Methods in Petrochemical Industry. Science Press, 1990:26). This double-adsorbent column separation method has a good separation effect on dewaxed oil of paraffin-based lubricating oil distillate, but the separation accuracy of heavy oil with high polycyclic aromatic hydrocarbon content and sulfur content is limited, and the crossover between components is serious. The adsorbent used in this method is a double adsorbent of alumina and silica gel, which has limited adsorption capacity for polycyclic aromatic hydrocarbons and sulfur-containing compounds. When separating heavy oil with high aromatic content, the processing capacity is small and the deactivation speed of the stationary phase is fast. , the adsorption and retention capacity of each component decreases, resulting in a decrease in the column efficiency of the separation column, and serious cross-contamination of the separated groups.

Modification of the stationary phase to moderately enhance the adsorption capacity of the stationary phase aromatics can improve the separation efficiency, shorten the separation time, and increase the processing capacity of the stationary phase oil. Gao Xiuxiang (Gao Xiuxiang et al. Research on the capture of olefins by silver-modified diatomite materials. Analytical Chemistry, 2003, 31 (8): 911-914) used silver salts to coat the surface of silica gel or silver ions as cation exchangers to The separation of olefins and saturated hydrocarbons is based on the fact that the sp hybrid orbitals in the outer layer of silver ions can interact strongly with the π electrons of olefins to form stable complexes, so the retention time on the chromatographic column increases, while saturated hydrocarbons Hydrocarbons do not contain functional groups that can interact with silver ions, and have almost no interaction with the stationary phase, thus achieving the purpose of separating saturated hydrocarbons from olefins.

Tao Xueming (Tao Xueming, Long Yicheng, Lu Wanzhen. Determination of Diesel Group Composition by High Performance Liquid Chromatography. Chromatography, 1995,13(5):368-372) using silver-type sulfonic acid bonded silica gel (Ag-SCX column) as the stationary phase , with benzene-modified n-hexane as the mobile phase, the separation of alkenes (C ₁₄ , C ₁₆ and C ₁₈ ) and alkanes (white oil) mixtures with different carbon chain lengths was achieved on high performance liquid chromatography. Similar to this, aromatic hydrocarbons contain large π bonds, which can interact with silver ions to a certain extent, and aromatic hydrocarbons with different ring numbers have different retention times on the column due to their different degrees of conjugation and different degrees of interaction with silver ions. Therefore, saturated hydrocarbons and aromatics can be separated according to this principle, and aromatics with different ring numbers can be separated.

Qiang Dongmei (Qiang Dongmei, Lu Wanzhen. Study on Separation Mechanism of Cyclohexene and Aromatic Hydrocarbons on Ag-SCX Column. Chromatography, 1998,16(3):187-190) Using Ag-SCX (Silver Column) as Stationary Phase , 3‰ cyclohexene/cyclohexane as the mobile phase, and the separation object is a 1:1 n-hexane solution prepared from dodecylbenzene, fluorene, and phenanthrene respectively with saturated hydrocarbons (lubricating oil fractions). Separation mechanism of alkenes and aromatics with different ring numbers on a silver column. It is pointed out in the paper that the chromatographic thermodynamic equilibrium constants of aromatics with different ring numbers are 121 (dodecylbenzene) > 21 (fluorene) > 13.8 (phenanthrene). The larger the equilibrium constant, the weaker the adsorption of aromatics on the silver column, so , the adsorption strength of arenes on the silver column increases with the increase of the ring number. These are all for the separation and analysis of trace amounts of several monomer hydrocarbon mixtures, which can only meet the purpose of analysis and testing, and cannot meet the needs of preparative separation of complex heavy oil samples.

For the separation of the vacuum distillate oil with large processing capacity, CN102079987A discloses that the silica gel loaded with a mass fraction of 13.2% silver nitrate is used as a stationary phase, and the vacuum wax oil is divided into saturated hydrocarbons with n-hexane, benzene, and ethanol as solvents respectively. The method of three components, aromatic hydrocarbons and colloids, has a better separation effect. However, this method does not further separate the aromatic components, and cannot meet the needs of further analysis and processing of aromatic components of different polarities. In addition, the silica gel loaded with silver ions in the stationary phase used in this method has a low adsorption strength for silver ions. When washing the colloidal components, an alumina column needs to be connected in series at the lower end of the device to avoid the silver ions being washed down. Into the separated components, while also increasing the steps and difficulty of operation.

Generally speaking, the above-mentioned stationary phase or column efficiency is too low, the separation efficiency is too poor, and there is a serious crossover between saturated hydrocarbons, light aromatics, medium aromatics and heavy aromatics; or the processing capacity is too small to meet the requirements of preparative separation. The separation requirements of the sample; or in the case of the same separation accuracy, the processing volume each time is too small to achieve preparative-level separation of different polar components in heavy oil; or a large amount of silver ions are eluted into each component Go, affect the subsequent analysis and detection of the separated components and the evaluation of processing performance.

Contents of the invention

The purpose of the present invention is to provide a method for solid-phase extraction and separation of components of heavy oil. The method uses aluminum oxide loaded with silver ions as a stationary phase to separate hydrocarbons with different polar components in heavy oil. Large amount, high separation efficiency and loaded silver ions are not easy to be eluted.

The method for separating components of heavy oil by solid phase extraction provided by the present invention comprises diluting the heavy oil and adding it to the stationary phase, then sequentially washing the stationary phase with C ₅ -C ₆ alkanes to obtain saturated hydrocarbon components, and using aromatic hydrocarbons and C ₅ -C 6 Wash the stationary phase with a solvent with a volume ratio of C ₆ alkanes of 1:15 to 25 to obtain light aromatic components, and wash the stationary phase with a solvent with a volume ratio of aromatics and C ₅ to C ₆ alkanes of 1:3 to 5 to obtain medium aromatic components. Rinse the stationary phase with aromatic hydrocarbons to obtain heavy aromatic components, wash the stationary phase with a solvent with aromatic hydrocarbons and monohydric alcohols at a volume ratio of 1:0.8 to 1.5 to obtain colloidal components, and the stationary phase is aluminum oxide loaded with silver ions. Silver ions account for 0.5-12% of the mass of alumina.

In the method of the present invention, the alumina loaded with silver ions is used as the stationary phase for separating heavy oil, and then different flushing agents are used to flush the stationary phase adsorbed on the heavy oil sample, and saturated hydrocarbons and light aromatics can be separated according to the polarity of the components. , medium aromatics, heavy aromatics and colloids, which can quickly provide the necessary sample volume for subsequent analysis tests and reaction evaluations.

detailed description

The method of the present invention adopts the aluminum oxide of loading silver ion as stationary phase, because the polarity that aluminum oxide has has stronger adsorption and retention capacity to silver ion, can make silver ion be more firmly loaded on the aluminum oxide carrier, thereby significantly Reducing the elution of silver ions by the extraction solvent not only ensures the separation efficiency and throughput of the stationary phase, but also reduces the possibility of silver ions being washed into the separated components. In addition, the flushing agent used in the present invention, that is, the extractant, can effectively separate the components adsorbed by the stationary phase according to their polarity. The fixed relatively heavy oil used has high processing capacity and good separation efficiency, and the loaded silver ions are not easy to be eluted by the flushing agent and flow into the separated components, so that the pollution of the separated components by the loss of silver ions can be effectively avoided, and the analysis accuracy can be improved. .

The silver ions loaded in the stationary phase provided by the present invention preferably account for 3.0 to 10.0% of the mass of alumina. It can be used alone, preferably together with silica gel, that is, the upper layer of the extraction separation column is filled with silica gel, and the middle layer is filled with silver ions. Aluminum, the lower layer can be filled with alumina, or not, to form a mixed stationary phase.

In the method of the present invention, preferred stationary phase comprises the silica gel that is positioned at the upper layer, the aluminum oxide that is positioned at the loading silver ion of middle layer and the neutral aluminum oxide that is positioned at lower floor, described silica gel: the aluminum oxide that loads silver ion: the mass ratio of aluminum oxide is 1: 2.5-5.0: 0-1.2, or 1: 2.5-5.0: 0.1-1.0.

In the stationary phase described in the method of the present invention, the alumina used for loading silver ions and the alumina used for the mixed stationary phase are preferably alumina with a neutral surface, more preferably γ-alumina with a neutral surface.

The specific surface area of the alumina is preferably 50 to 300 ^m2 /g, more preferably 120 to 300 ^m2 /g, the pore volume is preferably 0.10 to 0.55 ml/g, more preferably 0.20 to 0.35 ml/g, and the pore diameter of the alumina is Pores with a diameter of 25-75 nanometers account for 50-90% of the total pore volume.

In the mixed stationary phase described in the method of the present invention, the specific surface area of silica gel is preferably 250-850 ^m2 /g, more preferably 350-750 ^m2 /g, and the pore volume is preferably 0.25-0.99 ml/g, more preferably 0.30-0.96 ml/g. gram. The silica gel is preferably fine-pore silica gel, and the pores with a pore diameter of 20-40 nanometers preferably account for 50-95% of the total pore volume.

The external active center of the stationary phase of the present invention is the main body that interacts with the mobile phase and the sample, so that the loaded silver ions are distributed in an eggshell shape in the alumina, and the loaded silver ions can be utilized to the maximum extent. The vacuum impregnation method is to impregnate the alumina support with a solution containing silver ions under a certain degree of vacuum (decompression condition), so that the active components are more uniformly dispersed on the surface of the alumina. Under the action of capillary pressure, the impregnating solution penetrates into the interior of the alumina through the fine pores. The greater the concentration of silver ions, the greater the concentration gradient inside and outside the carrier, the easier it is to penetrate into the carrier, and the harder it is to form an eggshell catalyst. Prolonging the immersion time will also deepen the penetration of metal ions, making it difficult to form an eggshell distribution. Therefore, when preparing the alumina stationary phase loaded with silver ions in the present invention, it is preferable to impregnate the alumina with an impregnation solution with a low silver ion concentration, and the impregnation time should not be too long.

The preparation method of the stationary phase provided by the invention comprises the steps of immersing aluminum oxide in silver nitrate solution, stirring evenly, immersing at 20-70° C. for 0.5-5.0 hours under reduced pressure, and then drying.

The suitable concentration of the silver nitrate solution is preferably 0.2-10.0% by mass, preferably 0.5-6.0% by mass.

The pressure for impregnating alumina with silver nitrate solution is preferably 20-100 kPa, and the drying temperature after impregnation is preferably 100-200°C.

In the process of introducing silver nitrate by impregnation, the volume of the silver nitrate solution used for impregnation is 1 to 10 times, preferably 2 to 5 times, the pore volume of the carrier alumina. After impregnation, the alumina impregnated with silver salt (silver nitrate) is dried at 100-200° C., preferably 120-180° C., and the drying time is 1-30 hours, preferably 1-10 hours. The process of introducing silver nitrate by impregnation can be carried out multiple times, such as 1 to 3 times. The aluminum oxide loaded with silver nitrate obtained after drying is placed in a desiccator and stored away from light for future use.

When the stationary phase provided by the present invention is a mixed stationary phase containing multiple components, wherein silica gel, alumina and alumina loaded with silver ions can be packed in the same extraction separation column, or can be packed in different extraction separation columns . When packed in the same extraction and separation column, the silica gel is packed in the upper layer, the alumina is packed in the bottom layer, and the alumina loaded with silver ions is in the middle. When different extraction columns are used, the separation column filled with silica gel, the alumina separation column filled with silver ions, and the separation column filled with alumina are connected in series in sequence according to the upper, middle and lower.

The purpose of packing alumina at the bottom of the separation column is: when a large amount of solvent is used to elute the components of the oil sample adsorbed by the stationary phase, neutral alumina can be used to absorb a small amount of silver ions brought out by the solvent to prevent silver ions from entering into the separated components, causing analytical detection errors.

In the method of the present invention, when heavy oil is separated by solid phase extraction, the stationary phase is packed in the extraction separation column, and the diluted heavy oil is injected into the stationary phase from the upper part, and the saturated hydrocarbons, aromatic hydrocarbons and colloids are sequentially adsorbed by the stationary phase according to the polarity . Rinse the stationary phase with alkanes to obtain saturated hydrocarbon components, then use a mixture of aromatics and alkanes in different proportions to wash out light aromatics and medium aromatics in sequence, use aromatics to wash out heavy aromatics, and then use a mixture of aromatics and monohydric alcohols to wash out Colloidal component.

In the present invention, preferably, the upper layer of the alumina stationary phase loaded with silver ions is filled with silica gel. When dealing with heavy oil, the silica gel of the upper layer contacts the heavy oil before the alumina loaded with silver ions, which is beneficial to avoid polycyclic compounds with strong adsorption capacity. Aromatic hydrocarbons and sulfur-containing compounds are directly in contact with the alumina loaded with silver ions, resulting in a rapid decline in the adsorption and retention capacity of the fixed phase components, causing rapid deactivation of the stationary phase, and reducing the separation efficiency of the separation column.

In the method of the present invention, the diluent for diluting heavy oil is preferably C ₅ -C ₆ alkanes. The volume ratio of the diluent to heavy oil is 1-10:1, preferably 2-5:1.

The mass ratio of the stationary phase to the heavy oil is preferably 8-30:1, more preferably 12-21:1.

In the rinsing agent of the present invention for rinsing the light aromatic components adsorbed by the stationary phase, the volume ratio of aromatic hydrocarbons to C ₅ -C ₆ alkanes is preferably 1:18-23.

In the rinsing agent used for rinsing the middle aromatic components adsorbed by the stationary phase, the volume ratio of aromatic hydrocarbons to C ₅ -C ₆ alkanes is preferably 1:3-4.5.

In the rinsing agent used for rinsing colloids adsorbed by the stationary phase, the volume ratio of aromatic hydrocarbons to monohydric alcohols is preferably 1:0.8-1.2.

In the method of the present invention, the flushing agent used for flushing saturated hydrocarbons adsorbed by the stationary phase and the C ₅ -C ₆ alkanes used for diluting heavy oil are preferably n-pentane, n-hexane or petroleum ether.

The aromatics in the flushing agent used for flushing light aromatics, medium aromatics and heavy aromatics are preferably benzene or toluene.

The monohydric alcohol in the flushing agent used for flushing the gum is preferably methanol or ethanol.

In the above method, the volume ratio of the flushing agent used for each flushing of the stationary phase to the stationary phase is preferably 1-10, more preferably 1-6.

In the method of the present invention, the light aromatics separated by solid phase extraction are components enriched in single-ring aromatics, medium aromatics are components enriched in bicyclic aromatics, and heavy aromatics are components enriched in tricyclic and above aromatics.

The heavy oil described in the method of the present invention is vacuum distillate oil, deasphalted oil or catalytic cracking oil slurry. The aromatics content in the heavy oil is 5-90% by mass, and the sulfur content is 0.1-4.0% by mass.

The present invention is further described below with embodiment, but does not therefore limit the present invention.

The alumina used in the example is neutral alumina for chromatography produced by Sinopharm Chemical Reagent Co., Ltd., 74-149 microns, loss on ignition ≤ 8.0%, specific surface area 152m ² /g, pore volume 0.213mL/g, Pores with a pore diameter of 25-75 nm accounted for 85% of the total pore volume.

Silver nitrate was produced by Nanjing Chemical Reagent Co., Ltd., analytically pure, with a pH value (50g/L, 25°C) of 5.0-6.0.

Silica gel (silicon dioxide) is fine-porous silica gel produced by Qingdao Ocean Chemical Factory Branch, with a size of 74-149 microns, a specific surface area of 479m ² /g, a pore volume of 0.349mL/g, and pores with a diameter of 20-40 nanometers. 89% of the pore volume.

The instrument used in the example is a quadrupole gas chromatography-mass spectrometer (GC/MS), model Agilent7890GC/5975MS, 7693 automatic sampling tower. Gas chromatography (GC) working conditions: empty capillary column (30m×0.32mm), injection volume 1μL, split ratio 50:1, inlet temperature 310°C, carrier gas He, column flow in constant flow mode, flow rate 1.0 mL/min; the temperature program of the column oven is 40°C for 2min, then rise to 310°C at a rate of 60°C/min, and hold for 8min; mass spectrometry conditions: EI ionization source (70eV), ion source temperature 230°C, MS level 4 The rod temperature is 150°C, the MSD transmission line is 300°C; the solvent is delayed for 3 minutes; the data is collected by full scan (SCAN), and the mass range of the full scan is 50-700 amu.

Example 1

This example is used to illustrate the pretreatment and preparation process of silica, alumina and alumina loaded with silver ions in the present invention.

The fine-pored silica gel raw material was dried in a ventilated drying oven at 150° C. for 5 hours to obtain activated silica gel, which was stored in a desiccator for future use.

The neutral alumina was calcined at 550°C for 5 hours to obtain activated alumina, which was stored in a desiccator for later use.

Dissolve 7.41 grams of silver nitrate in 160 mL of deionized water to prepare a silver nitrate solution, take 200 grams of neutral alumina, add the alumina to the silver nitrate solution, stir evenly, and immerse at 60 °C under a pressure of 50 kPa for 4 hours, then Dry the aluminum oxide impregnated with silver nitrate at 150°C for 2 hours, cool to room temperature, then impregnate and dry again with the same volume and concentration of silver nitrate aqueous solution according to the above method, so that it is impregnated three times, and dried for 4 hours after the third impregnation to obtain Activated aluminum oxide A loaded with silver ions, wherein the silver ions account for 7.05% of the mass of the aluminum oxide. Place it in a desiccator to cool and bottle it, and keep it away from light for later use.

Example 2

This example illustrates the effect of using the stationary phase provided by the invention to separate components of vacuum distillate oil.

The bottom layer of the separation column is filled with 30g of neutral alumina, the middle is filled with 110g of silver ion-loaded alumina A, and the upper layer is filled with 30g of silica gel; the lower end of the separation column is connected to a vacuum system. The total volume of the stationary phase was 150 mL.

Take 10.20g (11.19mL) sample of Tahe vacuum distillate oil (distillation range 350～540°C), dissolve it in 30mL of n-hexane, first wet the stationary phase filled in the separation column with 100mL of n-hexane, and then put the above The n-hexane solution of the oil sample was added to the separation column. Use 170mL n-hexane to wash out saturated hydrocarbon components, 255mL toluene:n-hexane volume ratio of 1:19 solvent to wash out light aromatics components, and 255mL toluene:n-hexane volume ratio to wash out medium aromatics components 255mL of toluene washes out the heavy aromatic components, and 255mL of toluene: ethanol with a volume ratio of 1:1 washes out the colloidal components.

Adopt rotary evaporator to evaporate the solvent in saturated hydrocarbons, light aromatics, middle aromatics, heavy aromatics and colloids, obtain saturated hydrocarbons 4.94 grams, light aromatics 1.56 grams, middle aromatics 1.52 grams, heavy aromatics 0.92 grams, colloid 0.91 grams, Loss of 0.35 grams.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 0.9% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 74.3% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 37.1% by mass, and the content of heavy aromatic hydrocarbon was 37.1% by mass. The aromatic hydrocarbon content of three rings or more in the aromatic hydrocarbon component was 65.9% by mass.

After the separation was completed, the stationary phase was dried, and the silver ions in the alumina loaded with silver ions in the middle had been completely oxidized and turned black, while the neutral alumina filled at the bottom remained white, indicating that the silver ions had not been oxidized from the loaded alumina. Loss in aluminum.

Example 3

The components of the heavy oil sample were separated according to the method of Example 2, except that 10.11 g (11.09 mL) of the Liaohe vacuum distillate (distillation range 350-540° C.) sample was taken for solid-phase extraction separation. After separation, 5.48 grams of saturated hydrocarbons, 1.24 grams of light aromatics, 1.37 grams of medium aromatics, 0.73 grams of heavy aromatics, 1.18 grams of colloids and 0.11 grams of loss were obtained.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbons was 1.4 mass%, the content of single-ring aromatics in the light aromatics component was 72.9 mass%, the content of bicyclic aromatics in the middle aromatics component was 38.2 mass%, and the content of heavy aromatics The content of aromatic hydrocarbons with more than three rings in the middle was 67.8% by mass.

After the separation was completed, the stationary phase was dried, and the silver ions in the stationary phase loaded with silver ions in the middle had been completely oxidized and turned black, while the neutral alumina packed in the bottom layer remained white.

Example 4

Prepare the aluminum oxide of loaded silver ion by the method for example 1, difference is that the silver nitrate that adds when preparing silver nitrate solution is 1.36 grams, through dipping three times, obtain the aluminum oxide B of the loaded silver ion of activation, wherein silver ion accounts for 1.30% by mass of aluminum.

Fill the bottom layer of the separation column with 30g of neutral alumina, the middle with 110g of silver ion-loaded alumina B, and the upper layer with 30g of silica gel; connect the lower end of the separation column to a vacuum system. The total volume of the stationary phase was 160 mL.

Take 10.13g (11.11mL) sample of Tahe decompression distillate oil (distillation range 350～540℃), dissolve it in 30mL of n-hexane, first wet the stationary phase filled in the separation column with 100mL of n-hexane, and then put the above The n-hexane solution of the oil sample was added to the separation column. Use 170mL n-hexane to wash out saturated hydrocarbon components, 255mL toluene:n-hexane volume ratio of 1:19 solvent to wash out light aromatics components, and 255mL toluene:n-hexane volume ratio to wash out medium aromatics components 255mL of toluene washes out the heavy aromatic components, and 255mL of toluene: ethanol with a volume ratio of 1:1 washes out the colloidal components.

Adopt rotary evaporator to evaporate the solvent in saturated hydrocarbons, light aromatics, middle aromatics, heavy aromatics and colloids, obtain saturated hydrocarbons 5.28 grams, light aromatics 1.41 grams, middle aromatics 1.18 grams, heavy aromatics 1.01 grams, colloid 0.94 grams, Loss of 0.20 grams.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 6.7% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 56.5% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 28.9% by mass, and the content of heavy aromatic hydrocarbon was 28.9% by mass. The content of aromatic hydrocarbons with three or more rings in the aromatic hydrocarbons was 56.8% by mass.

After the separation was completed, the stationary phase was dried, and the silver ions in the alumina loaded with silver ions in the middle had been completely oxidized and turned black, while the neutral alumina filled at the bottom remained white, indicating that the silver ions had not been oxidized from the loaded alumina. Loss in aluminum.

Example 5

Prepare the aluminum oxide of loaded silver ion by the method for example 1, difference is that the silver nitrate that adds when preparing silver nitrate solution is 5.80 grams, through dipping three times, obtain the aluminum oxide C of the loaded silver ion of activation, wherein silver ion accounts for oxidized 5.52% of aluminum mass.

The bottom layer of the separation column is filled with 30g of neutral alumina, the middle is filled with 110g of silver nitrate-loaded alumina C, and the upper layer is filled with 30g of silica gel; the lower end of the separation column is connected to a vacuum system. The total volume of the stationary phase was 153 mL.

Take 10.25g (11.24mL) sample of Tahe decompression distillate oil (distillation range 350～540°C), dissolve it in 30mL of n-hexane, first wet the stationary phase filled in the separation column with 100mL of n-hexane, and then put the above The n-hexane solution of the oil sample was added to the separation column. Use 170mL n-hexane to wash out saturated hydrocarbon components, 255mL toluene:n-hexane volume ratio of 1:19 solvent to wash out light aromatics components, and 255mL toluene:n-hexane volume ratio to wash out medium aromatics components 255mL of toluene washes out the heavy aromatic components, and 255mL of toluene: ethanol with a volume ratio of 1:1 washes out the colloidal components.

Adopt rotary evaporator to evaporate the solvent in saturated hydrocarbons, light aromatics, middle aromatics, heavy aromatics and colloids, obtain saturated hydrocarbons 4.89 grams, light aromatics 1.59 grams, middle aromatics 1.47 grams, heavy aromatics 1.02 grams, colloid 1.05 grams, Loss of 0.23 grams.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 2.4% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 71.8% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 34.7% by mass, and the content of heavy aromatic hydrocarbon was 34.7% by mass. The content of aromatic hydrocarbons with three or more rings in the aromatic hydrocarbon component was 64.4% by mass.

After the separation was completed, the stationary phase was dried, and the silver ions in the alumina loaded with silver ions in the middle had been completely oxidized and turned black, while the neutral alumina filled at the bottom remained white, indicating that the silver ions had not been oxidized from the loaded alumina. Loss in aluminum.

Example 6

Prepare the aluminum oxide of loaded silver ion by the method for example 1, difference is that the silver nitrate that adds when preparing silver nitrate solution is 10.14 grams, through dipping three times, obtain the aluminum oxide D of the loaded silver ion of activation, wherein silver ion accounts for 9.66% of aluminum mass.

The bottom layer of the separation column is filled with 30g of neutral alumina, the middle is filled with 110g of silver nitrate-loaded alumina D, and the upper layer is filled with 30g of silica gel; the lower end of the separation column is connected to a vacuum system. The total volume of the stationary phase was 145 mL.

Take 10.06g (11.03mL) sample of Tahe vacuum distillate oil (distillation range 350～540℃), dissolve it in 30mL of n-hexane, first wet the stationary phase filled in the above separation column with 100mL of n-hexane, and then put the above The n-hexane solution of the oil sample was added to the separation column. Use 170mL n-hexane to wash out saturated hydrocarbon components, 255mL toluene:n-hexane volume ratio of 1:19 solvent to wash out light aromatics components, and 255mL toluene:n-hexane volume ratio to wash out medium aromatics components 255mL of toluene washes out the heavy aromatic components, and 255mL of toluene: ethanol with a volume ratio of 1:1 washes out the colloidal components.

Adopt rotary evaporator to evaporate the solvent in saturated hydrocarbons, light aromatics, middle aromatics, heavy aromatics and colloids, obtain saturated hydrocarbons 4.87 grams, light aromatics 1.58 grams, middle aromatics 1.43 grams, heavy aromatics 1.05 grams, colloid 0.96 grams, Loss of 0.17 grams.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 0.7% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 74.6% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 38.5% by mass, and the content of heavy aromatic hydrocarbon was 38.5% by mass. The content of aromatic hydrocarbons having three or more rings in the aromatic hydrocarbon component was 68.3% by mass.

After the separation was completed, the stationary phase was dried, and the silver ions in the loaded silver-ion-loaded alumina in the middle had been completely oxidized and turned black, while the neutral alumina filled at the bottom remained white, indicating that the silver ions had not been removed from the loaded alumina. lost in alumina.

Comparative example 1

This paper illustrates the conventional column separation effect of vacuum distillate oil using the stationary phase composed of neutral alumina and silica gel.

Fill the lower layer of the separation column with 85g of neutral alumina, and the upper layer with 85g of silica gel; connect the lower end of the separation column to the vacuum system. The total volume of the stationary phase was 185 mL.

Take 10.02g (10.99mL) sample of Tahe vacuum distillate oil (distillation range 350～540℃), dissolve it in 30mL of n-hexane, first wet the stationary phase filled in the separation column with 100mL of n-hexane, and then put the above The n-hexane solution of the oil sample was added to the separation column. Use 170mL n-hexane to wash out saturated hydrocarbon components, 255mL toluene:n-hexane volume ratio of 1:19 solvent to wash out light aromatics components, and 255mL toluene:n-hexane volume ratio to wash out medium aromatics components 255mL of toluene washes out the heavy aromatic components, and 255mL of toluene: ethanol with a volume ratio of 1:1 washes out the colloidal components.

After adopting rotary evaporator to evaporate the solvent in saturated hydrocarbons, light aromatics, middle aromatics, heavy aromatics and colloid, weigh, obtain saturated hydrocarbon sample 4.97 grams, light aromatics 2.14 grams, middle aromatics 1.12 grams, heavy aromatics 0.76 grams, Colloid 0.74 grams, loss 0.29 grams.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 4.3% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 60.7% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 27.5% by mass, and the content of heavy aromatic hydrocarbon was 27.5% by mass. The content of aromatic hydrocarbons with three or more rings in the aromatic hydrocarbon component was 52.5% by mass.

From the results of this comparative example, it can be seen that the content of the separation target component in the separated components obtained by using the aluminum oxide not loaded with silver ions is lower than that of the present invention, indicating that the separation efficiency of the stationary phase is low.

Comparative example 2

Dissolve 10.14 grams of silver nitrate in 160 mL of deionized water to prepare a silver nitrate solution, add 200 grams of fine-pore silica gel to the silver nitrate solution, stir evenly, and immerse at 60°C for 4 hours under vacuum (0.5kPa), then place Silica gel impregnated with silver nitrate was dried at 150°C for 2 hours, cooled to room temperature, then impregnated and dried again with the same volume and concentration of silver nitrate aqueous solution according to the above method, so that it was impregnated three times, and dried for 4 hours after the third impregnation to obtain activated Silica gel loaded with silver ions, in which silver ions account for 9.66% of the mass of silica gel.

The bottom layer of the separation column is filled with 30g of neutral alumina, the middle is filled with 110g of silver ion-loaded silica gel, and the upper layer is filled with 30g of silica gel; the lower end of the separation column is connected to a vacuum system. The total volume of the stationary phase was 163 mL.

Take 10.20g (11.19mL) sample of Tahe vacuum distillate oil (distillation range 350～540°C), dissolve it in 30mL of n-hexane, first wet the stationary phase filled in the separation column with 100mL of n-hexane, and then put the above The n-hexane solution of the oil sample was added to the separation column. Use 170mL n-hexane to wash out saturated hydrocarbon components, 255mL toluene:n-hexane volume ratio of 1:19 solvent to wash out light aromatics components, and 255mL toluene:n-hexane volume ratio to wash out medium aromatics components 255mL of toluene washes out the heavy aromatic components, and 255mL of toluene: ethanol with a volume ratio of 1:1 washes out the colloidal components.

After adopting rotary evaporator to evaporate the solvent in saturated hydrocarbons, light aromatics, middle aromatics, heavy aromatics and colloid, weigh, obtain saturated hydrocarbon sample 4.84 grams, light aromatics 1.71 grams, middle aromatics 1.36 grams, heavy aromatics 0.87 grams, Colloid 0.81 g, loss 0.41 g.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 1.3% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 73.8% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 37.1% by mass, and the content of heavy aromatic hydrocarbon was 37.1% by mass. The content of aromatic hydrocarbons with three or more rings in the aromatic hydrocarbon component was 65.9% by mass.

After the separation is completed, the stationary phase is dried, and the silver ions in the stationary phase loaded with silver ions in the middle have been completely oxidized and turned black, and the neutral alumina loaded at the bottom is also completely black, which is different from heavy aromatics and colloids. It is consistent with the phenomenon that the yield of quality is high, indicating that a certain amount of silver ions fall off from the silica gel and are washed into the neutral alumina.

The results of this comparative example show that using silica gel loaded with silver ions as the stationary phase requires a large amount of loaded silver ions, and the loaded silver ions should be eluted by the washing solvent.

Comparative example 3

The bottom layer of the separation column is filled with 75g of neutral alumina, the middle is filled with 65g of alumina A loaded with silver nitrate, and the upper layer is filled with 30g of silica gel; the lower end of the separation column is connected to a vacuum system. The total volume of the stationary phase was 152 mL.

Take 10.04g (11.01mL) sample of Tahe vacuum distillate oil (distillation range 350～540℃), dissolve it in 30mL of n-hexane, first wet the stationary phase filled in the separation column with 100mL of n-hexane, and then put the above The n-hexane solution of the oil sample was added to the separation column. Use 170mL n-hexane to wash out saturated hydrocarbon components, 255mL toluene:n-hexane volume ratio of 1:19 solvent to wash out light aromatics components, and 255mL toluene:n-hexane volume ratio to wash out medium aromatics components 255mL of toluene washes out the heavy aromatic components, and 255mL of toluene: ethanol with a volume ratio of 1:1 washes out the colloidal components.

After adopting rotary evaporator to evaporate the solvent in saturated hydrocarbons, light aromatics, middle aromatics, heavy aromatics and colloid, weigh, obtain saturated hydrocarbon sample 5.12 grams, light aromatics 1.41 grams, middle aromatics 1.27 grams, heavy aromatics 1.14 grams, Colloid 1.02 grams, loss 0.08 grams.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 4.7% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 75.8% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 33.3% by mass, and the content of heavy aromatic hydrocarbon was 33.3% by mass. The content of aromatic hydrocarbons having three or more rings in the aromatic hydrocarbon component was 50.2% by mass.

After the separation is completed, dry the stationary phase. The silver ions in the stationary phase loaded with silver ions in the middle have been completely oxidized and turned black, while the neutral alumina filled in the bottom layer remains white, indicating that the silver ions have not been oxidized from the loaded phase. Loss in aluminum.

The results of this comparative example show that using a relatively small amount of alumina loaded with silver nitrate as the stationary phase, among the separated components, the content of alkylbenzene in the saturated hydrocarbon component is more, and the content of aromatic hydrocarbons with more than three rings in the heavy aromatic component is relatively high. content decreased, indicating that the separation efficiency is poor.

Comparative example 4

This comparative example illustrates the effect of flushing the aromatics component with different volume ratios of the flushing agent.

According to the method of Example 2, 10.18g (11.17mL) of Tahe decompression distillate oil (distillation range 350-540°C) sample was separated by solid-phase extraction. The solvent of 1:5.7 washes out the middle aromatic components. After evaporating the solvents in saturated hydrocarbons, light aromatics, medium aromatics, heavy aromatics and colloids through a rotary evaporator, 5.19 grams of saturated hydrocarbon samples, 1.45 grams of light aromatics, 1.31 grams of medium aromatics, 1.16 grams of heavy aromatics, and 0.97 grams of colloids were obtained. grams, loss of 0.1 grams.

GC/MS analysis showed that the content of alkylbenzene in the saturated hydrocarbon component was 1.3% by mass, the content of single-ring aromatic hydrocarbon in the light aromatic component was 75.7% by mass, the content of bicyclic aromatic hydrocarbon in the middle aromatic component was 38.0% by mass, and the content of heavy aromatic hydrocarbon was 38.0% by mass. The content of aromatic hydrocarbons having three or more rings in the aromatic hydrocarbon component was 52.5% by mass.

After the separation was completed, the stationary phase was dried, and the silver ions in the stationary phase loaded with silver ions in the middle had been completely oxidized and turned black, while the alumina without silver ions loaded in the lower end remained white.

This comparative example shows that in the solvent of the aromatics component in the flushing, reducing the proportion of toluene can slightly increase the content of bicyclic aromatics in the middle aromatics component, but it will lead to the content of aromatics with three rings or more in the heavy aromatics component obtained by washing. Decreased significantly.

Claims (14)

1. A method for solid-phase extraction and separation of components of heavy oil, comprising diluting the heavy oil and adding it to the stationary phase, then washing the stationary phase with _C5 - _C6 alkane successively to obtain saturated hydrocarbon components, and using aromatic hydrocarbons and _C5 -C6 Wash the stationary phase with a solvent with a volume ratio of C ₆ alkanes of 1:15 to 25 to obtain light aromatic components, and wash the stationary phase with a solvent with a volume ratio of aromatics and C ₅ to C ₆ alkanes of 1:3 to 5 to obtain medium aromatic components. Rinse the stationary phase with aromatic hydrocarbons to obtain heavy aromatic components, wash the stationary phase with a solvent with aromatic hydrocarbons and monohydric alcohols at a volume ratio of 1:0.8 to 1.5 to obtain colloidal components, and the stationary phase is aluminum oxide loaded with silver ions. Silver ions account for 3-10% of the mass of alumina, the aromatic hydrocarbon is benzene or toluene, and the monohydric alcohol is methanol or ethanol. 2. according to the described method of claim 1, it is characterized in that described stationary phase comprises the silica gel that is positioned at upper strata, is positioned at the aluminum oxide of the loading silver ion of middle layer and is positioned at the aluminum oxide of lower floor, described silica gel: the oxidation of loading silver ion The mass ratio of aluminum:alumina is 1:2.5-5.0:0-1.2. 3. The method according to claim 2, characterized in that the mass ratio of silica gel: silver ion loaded alumina: alumina is 1:2.5-5.0:0.1-1.0. 4. The method according to claim 1 or 2, characterized in that the specific surface area of the alumina is 50-300 ^m2 /g, and the pore volume is 0.10-0.55 ml/g. 5. The method according to claim 4, characterized in that the specific surface area of the alumina is 120-300 ^m2 /g, the pore volume is 0.20-0.35 ml/g, and the pore diameter is 25-75 nanometers. 30-90% of the total pore volume. 6. The method according to claim 1 or 2, characterized in that the alumina is surface-neutral alumina. 7. The method according to claim 2, characterized in that the specific surface area of the silica gel is 250-850 m ² /g, and the pore volume is 0.25-0.99 ml/g. 8. The method according to claim 2, characterized in that the specific surface area of the silica gel is 350 to 750 ^m2 /g, the pore volume is 0.30 to 0.96 ml/g, and the pore diameter is 20 to 40 nanometers. 50-95% of the pore volume. 9. The method according to claim 1, characterized in that the silver ions are distributed in the alumina in an eggshell shape in the alumina loaded with silver ions. 10. The method according to claim 1, characterized in that the diluent used to dilute the heavy oil is a C ₅ -C ₆ alkane, and the volume ratio of the diluent to the heavy oil is 1-10:1. 11. The method according to claim 1 or 10, characterized in that said C ₅ -C ₆ alkane is n-pentane, n-hexane or petroleum ether. 12. The method according to claim 1, characterized in that the mass ratio of stationary phase to heavy oil is 8-30:1. 13. The method according to claim 1, characterized in that the heavy oil is vacuum distillate oil, deasphalted oil or catalytic cracking oil slurry. 14. The method according to claim 13, characterized in that the aromatics content in the heavy oil is 5-90% by mass, and the sulfur content is 0.1-4.0% by mass.