Method for determining polycyclic condensed aromatic hydrocarbons in bitumen and petroleum fractions containing asphaltenes

Abstract

The present application relates to a kind of polycyclic condensed aromatic hydrocarbon determination method in asphalt and asphaltene-containing petroleum fraction.The method steps are: the sample with weight m1 is removed asphaltene, as intermediate sample, placed in separating funnel F1;DMSO is added in F1, extract is placed in separating funnel F2, raffinate is left in F1;DMSO is added to F1, extract is combined in F2, raffinate is left in F1;Cyclohexane, sodium chloride aqueous solution and alcoholic solvent are added in F2, extract is mixed system F3, raffinate is combined in F1;Cyclohexane is added to F3, extract is placed in container C1, raffinate is combined in F1;Sodium chloride aqueous solution is added to F1, extract is combined in C1;Raffinate is left in F1;Step 7, remove cyclohexane solvent, the weight of remaining substance m2;The ratio of m2 and m1 is calculated, and the content of PCA is obtained.The present application improves analysis accuracy and efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the detection of petroleum chemical products, in particular to a method for determining polycyclic condensed aromatics in asphalt and petroleum fractions containing asphaltene. BACKGROUND

[0002] In petroleum fractions or fraction-type petroleum products, such as environmentally friendly rubber filling oil, the polycyclic condensed aromatic (PCA) content is used as a standard for evaluating whether the oil product is environmentally friendly. For example, in the environmentally friendly rubber filling oil used for tire production in the European Union, the technical requirement that the PCA is not greater than 3% is explicitly specified. The PCA requirement is also proposed for environmentally friendly rubber oil in China, and the Determination of Polycyclic Aromatic Hydrocarbons in Petroleum Fractions Containing No Asphaltene—Dimethyl Sulfoxide Extraction Refractive Index Method (NB / SH / T 0838-2010) is published. The method explicitly provides that this standard is applicable to the determination of the content of polycyclic aromatic hydrocarbons (PCA) in petroleum fractions containing no asphaltene. With the continuous improvement of national environmental protection requirements, new requirements for the environmental performance of petroleum asphalt are proposed. When the mixture produced by asphalt and inorganic aggregate is paved on the asphalt pavement, the polycyclic condensed aromatics in the asphalt microparticles suspended in the air pollute the air.

[0003] Because asphalt contains asphaltene, when PCA is determined by NB / SH / T0838-2010, the extraction of PCA in dimethyl sulfoxide (DMSO) cannot be achieved due to the interference of asphaltene. Therefore, the asphaltene needs to be removed by pretreatment. In addition, the soluble component after removing the asphaltene has a large molecular weight, high viscosity, and contains heteroatoms. When PCA is determined by NB / SH / T0838-2010, it is easy to emulsify and difficult to separate into layers. The test is time-consuming, and the experimental results have poor repeatability and reproducibility. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a method for removing asphaltene in asphalt and petroleum fractions containing asphaltene. The sample after removing the asphaltene is used as the test sample, and the sample is completely dissolved in the dilution solvent cyclohexane, thereby eliminating the interference of the asphaltene. An auxiliary solvent is provided, which improves the extraction and separation effect of the cyclohexane-deasphaltene asphalt component-dimethyl sulfoxide-sodium chloride aqueous solution system, and improves the accuracy of the analysis results and the test efficiency.

[0005] The method for determining polycyclic condensed aromatics in asphalt and petroleum fractions containing asphaltene according to the present application comprises the following steps in sequence:

[0006] Step 1, removing asphaltene, take a sample of asphalt or petroleum fraction containing asphaltene with weight m1, dissolve in a certain volume of cyclohexane solvent, reflux dissolution, quantitative filter paper filtration, reflux washing residual soluble components on filter paper, get cyclohexane solution of removed cyclohexane insoluble (asphaltene), as intermediate sample for subsequent dimethyl sulfoxide extraction, placed in separatory funnel F1;

[0007] Step 2, add DMSO in F1 for extraction, extract liquid is DMSO solution of residual part PCA, placed in separatory funnel F2, extract residue is cyclohexane solution containing PCA, left in F1;

[0008] Step 3, add DMSO in F1 for extraction, extract liquid is combined in F2, extract residue is left in F1;

[0009] Step 4, add cyclohexane and 4% mass concentration sodium chloride aqueous solution in F2, at the same time add methanol or ethanol or low carbon alcohol solvent for extraction, extract liquid is mixed system F3 of DMSO, water, salt, alcohol solvent and sample components dissolved in the solvent system, extract residue is combined in F1;

[0010] Step 5, add cyclohexane in F3 for extraction, extract liquid is placed in container C1, extract residue is combined in F1;

[0011] Step 6, add 65-75℃ sodium chloride aqueous solution in F1 for extraction, extract liquid is mixture of water, salt and alcohol solvent, combined in C1; extract residue is cyclohexane solution containing PCA, left in F1;

[0012] Step 7, remove cyclohexane solvent in F1 by evaporation and vacuum drying, take weight m2 of the material after removing solvent;

[0013] Step 8, calculate, m2 / m1x100, that is PCA content, expressed by %.

[0014] Preferably, in step 1, the ratio of sample quantity in g to cyclohexane solvent quantity in ml is 1:5-1:50, further preferably, the ratio of sample to cyclohexane solvent is 1:10-1:20.

[0015] Preferably, in step 2, the ratio of sample quantity in g to DMSO quantity in ml is 1:20-1:100, further preferably, the ratio of sample to DMSO is 1:20-1:40.

[0016] Preferably, in step 3, the ratio of the sample amount in g to the DMSO amount in ml is 1:20-1:200, and further preferably, the ratio of the sample to DMSO is 1:40-1:80.

[0017] Preferably, in step 4, a certain amount of cyclohexane and a 4% sodium chloride aqueous solution are added to the combined F2, and methanol or ethanol or a low-carbon alcohol solvent is added at the same time, the volume ratio of cyclohexane: sodium chloride aqueous solution: alcohol solvent is 1:10:1-20, and further preferably, the ratio is 1:10:2-3; the ratio of the sample amount in g to the mixed solvent amount in ml is 1:5-1:50, and further preferably, the ratio of the sample to the mixed solvent is 1:10-1:20.

[0018] Preferably, in step 5, the ratio of the sample amount in g to the cyclohexane amount in ml is 1:5-1:50, and further preferably, the ratio of the sample to the cyclohexane solvent is 1:10-1:20.

[0019] Preferably, in step 6, the ratio of the sample amount in g to the cyclohexane amount in ml is 1:2-1:20, and further preferably, the ratio of the sample to the cyclohexane solvent is 1:5-1:10.

[0020] Preferably, in step 7, the evaporation temperature for removing the cyclohexane solvent is 80-100°C; the vacuum drying conditions are a residual pressure of 10-100 mmHg and a temperature of 110-150°C, and further preferably, the residual pressure is 30-50 mmHg.

[0021] The advantages of the present application are that when the PCA of asphalt or petroleum fractions containing asphaltene is determined, the repeatability of the detection result is improved from 3% to within 1%, the reproducibility is improved from 5% to within 2%, and the extraction and sedimentation separation time in steps 2-6 is shortened from 240 min to within 100 min. DETAILED DESCRIPTION

[0022] Example One

[0023] Sample to be tested: AH-70 heavy traffic road asphalt, cyclohexane insoluble (asphaltene) content 12.5%

[0024] Detection steps:

[0025] Step 1: weigh 3.587 g of asphalt sample, add 60 ml of cyclohexane, reflux and dissolve, filter with quantitative filter paper, and reflux and wash the residual soluble components on the filter paper to obtain a cyclohexane solution from which the cyclohexane insoluble (asphaltene) has been removed, which is used as the sample for subsequent dimethyl sulfoxide extraction, and placed in a separatory funnel F1;

[0026] Step 2, add DMSO 100 ml to F1 for extraction, the raffinate is the cyclohexane solution containing PCA, which is reserved in F1, and the extract is the DMSO solution of the residual PCA, which is placed in the separatory funnel F2;

[0027] Step 3, add DMSO 150 ml to F1, combine the extract in F2, and combine the raffinate in F1;

[0028] Step 4, add 50 ml of mixed solvent to the combined F2, the volume ratio of cyclohexane: sodium chloride aqueous solution: alcohol solvent in the mixed solvent is 1:10:2, combine the raffinate in F1, and the extract is the mixed system of DMSO, water, salt, alcohol solvent and sample components dissolved in the solvent system, which is placed in the separatory funnel F3;

[0029] Step 5, add cyclohexane 50 ml to F3, combine the raffinate in F1, and place the extract in a closed container C1;

[0030] Step 6, add 20 ml of 70℃ sodium chloride aqueous solution to F1, the raffinate is the cyclohexane solution containing the PCA to be measured, which is reserved in F1, and the extract is the mixture of water, salt and alcohol solvent, which is combined in C1;

[0031] Step 7, transfer the solution in F1 to a triangular flask, control the water bath temperature to be 82-84℃, evaporate most of the cyclohexane solvent, place the triangular flask in a vacuum drying oven at 115-120℃ and a residual pressure of 50-60 mmHg for heating for 60 min, take out and place in a desiccator, cool at room temperature for 60 min, and weigh, the weight m2 of PCA is 0.8531 g;

[0032] Step 8, according to m1 of 3.587 g and m2 of 0.8531 g, the PCA content of the asphalt is 23.7%;

[0033] The time used in steps 2-6 above is 80 min, steps 1-8 are repeated three times, and the test repeatability is 0.7%.

[0034] Example Two

[0035] Sample to be measured: AH-90 heavy traffic road asphalt, cyclohexane insoluble (asphaltene) content 7.6%

[0036] Detection steps:

[0037] Step 1, take 4.676g asphalt sample, add cyclohexane 50ml, reflux dissolution, quantitative filter paper filtration, reflux washing residual soluble components on filter paper, get cyclohexane solution of cyclohexane insoluble (asphaltene) removed, as sample of subsequent dimethyl sulfoxide extraction, place in separatory funnel F1;

[0038] Step 2, add DMSO 120ml to F1 for extraction, raffinate is cyclohexane solution containing PCA, keep in F1, extract is DMSO solution of residual part PCA, place in separatory funnel F2;

[0039] Step 3, add DMSO 250ml to F1, combine extract in F2, keep raffinate in F1;

[0040] Step 4, add 100ml mixed solvent to combined F2, volume ratio of cyclohexane: sodium chloride aqueous solution: alcohol solvent in mixed solvent is 1:10:3, combine raffinate in F1, extract is mixed system of DMSO, water, salt, alcohol solvent and sample components dissolved in the solvent system, place in separatory funnel F3;

[0041] Step 5, add cyclohexane 110ml to F3, combine raffinate in F1, place extract in closed container C1;

[0042] Step 6, add 50ml 70℃ sodium chloride aqueous solution to F1, raffinate is cyclohexane solution containing PCA to be measured, keep in F1, combine extract which is mixture of water, salt, alcohol solvent in C1;

[0043] Step 7, transfer solution in F1 to a flask, control water bath temperature to be 83-87℃, evaporate most of cyclohexane solvent, place flask in vacuum drying oven at 120-125℃, residual pressure 70-80mmHg, heat for 60min, take out and place in desiccator, cool for 60min at room temperature, weigh, weight m2 of PCA is 1.0316g;

[0044] Step 8, according to m1 is 4.676g, m2 is 0.3316g, then PCA content of the asphalt is 22.1%;

[0045] Time used in above steps 2-6 is 70min, repeat steps 1-8 three times, test repeatability is 0.8%;

[0046] Example three

[0047] Sample to be measured: A-180 road petroleum asphalt, cyclohexane insoluble (asphaltene) content 2.2%

[0048] Detection steps:

[0049] Step 1, take 5.287g asphalt sample, add cyclohexane 30ml, reflux dissolution, quantitative filter paper filtration, reflux washing residual soluble components on filter paper, get cyclohexane solution of cyclohexane insoluble (asphaltene) removed, as sample of subsequent dimethyl sulfoxide extraction, place in separatory funnel F1;

[0050] Step 2, add DMSO 120ml to F1 for extraction, raffinate is cyclohexane solution containing PCA, keep in F1, extract is DMSO solution of residual part PCA, place in separatory funnel F2;

[0051] Step 3, add DMSO 400ml to F1, combine extract in F2, keep raffinate in F1;

[0052] Step 4, add 250ml mixed solvent to combined F2, volume ratio of cyclohexane: sodium chloride aqueous solution: alcohol solvent in mixed solvent is 1:10:5, combine raffinate in F1, extract is mixed system of DMSO, water, salt, alcohol solvent and sample components dissolved in the solvent system, place in separatory funnel F3;

[0053] Step 5, add cyclohexane 100ml to F3, combine raffinate in F1, place extract in closed container C1;

[0054] Step 6, add 20ml 70℃ sodium chloride aqueous solution to F1, raffinate is cyclohexane solution containing PCA to be measured, keep in F1, combine extract which is mixture of water, salt, alcohol solvent in C1;

[0055] Step 7, transfer solution in F1 to a flask, control water bath temperature to be 83-87℃, evaporate most of cyclohexane solvent, place the flask in vacuum drying oven at 120-125℃, residual pressure 70-80mmHg, heat for 60min, take out and place in desiccator, cool for 60min at room temperature, weigh, weight m2 of PCA is 1.3217g;

[0056] Step 8, according to m1 is 5.287g, m2 is 1.3217g, then PCA content of the asphalt is 25.1%;

[0057] Time used in above steps 2-6 is 90min, fully repeat steps 1-8 three times, test repeatability is 0.5%.

[0058] Example Four

[0059] Sample to be measured: atmospheric residue, cyclohexane insoluble (asphaltene) content 3.5%

[0060] Detection steps:

[0061] Step 1, weigh 6.257g of asphalt sample, add cyclohexane 40ml, reflux dissolution, quantitative filter paper filtration, reflux washing residual soluble components on filter paper, get cyclohexane solution of cyclohexane insoluble (asphaltene) removed, as sample for subsequent dimethyl sulfoxide extraction, placed in F1;

[0062] Step 2, add DMSO 150ml to F1 for extraction, raffinate is cyclohexane solution containing PCA, left in F1, extract is DMSO solution of residual part of PCA, placed in separatory funnel F2;

[0063] Step 3, add DMSO 300ml to F1, extract placed in F2, raffinate left in F1;

[0064] Step 4, add 180ml mixed solvent to combined F2, volume ratio of cyclohexane: sodium chloride aqueous solution: alcohol solvent in mixed solvent is 1:10:5, raffinate combined in F1, extract is mixed system of DMSO, water, salt, alcohol solvent and sample components dissolved in the solvent system, placed in separatory funnel F3;

[0065] In step 5, add cyclohexane 120ml to F3, raffinate combined in F1, extract placed in closed container C1;

[0066] In step 6, add 25ml of 70℃ sodium chloride aqueous solution to F1, raffinate is cyclohexane solution F1 containing PCA to be measured, extract is mixture of water, salt, alcohol solvent, combined C1;

[0067] In step 7, transfer solution in F1 to a triangular flask, control water bath temperature to be 83-87℃, evaporate to remove most of cyclohexane solvent, place the triangular flask in a vacuum drying oven at 120-125℃, residual pressure 70-80mmHg, heat for 60min, remove to desiccator, cool at room temperature for 60min, weigh, weight m2 of PCA is 1.8656g;

[0068] Step 8, according to m1 is 6.257g, m2 is 1.8656g, then PCA content of the asphalt is 29.8%;

[0069] Time used in above steps 2-6 is 85min, repeat steps 1-8 three times, test repeatability is 0.7%.

Claims

1. A method for the determination of polycyclic condensed aromatic hydrocarbons in bitumen and in petroleum fractions containing asphaltenes, characterized in that: Comprise the following steps in turn, Step 1, removing asphaltene, taking a sample of asphalt or petroleum fraction containing asphaltene with weight m1, dissolving in cyclohexane solvent, refluxing, filtering with quantitative filter paper, washing the residual soluble components on the filter paper with reflux, obtaining cyclohexane solution from which the cyclohexane insoluble components are removed, as the intermediate sample for subsequent dimethyl sulfoxide extraction, and placing in separatory funnel F1; Step 2, adding DMSO in F1 for extraction, the extract is DMSO solution of residual part PCA, and placing in separatory funnel F2, and the raffinate is cyclohexane solution containing PCA, and remaining in F1; Step 3, adding DMSO in F1 for extraction, and combining the extract in F2, and remaining the raffinate in F1; Step 4, adding cyclohexane and 4% sodium chloride aqueous solution in mass concentration in F2, and adding methanol or ethanol or low carbon alcohol solvent at the same time for extraction, and the extract is mixed system F3 of DMSO, water, salt, alcohol solvent and sample components dissolved in the solvent system, and combining the raffinate in F1; Step 5, adding cyclohexane in F3 for extraction, and placing the extract in container C1, and combining the raffinate in F1; Step 6, adding 65-75℃ sodium chloride aqueous solution in F1 for extraction, and the extract is mixture of water, salt and alcohol solvent, and combining in C1; and the raffinate is cyclohexane solution containing PCA, and remaining in F1; Step 7, removing cyclohexane solvent in F1 through evaporation and vacuum drying, and taking the weight m2 of the substance after removing the solvent; Step 8, calculating the ratio of m2 and m1 to obtain the content of PCA; In step 1, the ratio of sample quantity in g to cyclohexane solvent quantity in ml is 1:5-1:50; In step 4, the volume ratio of cyclohexane, sodium chloride aqueous solution and alcohol solvent added in the combined F2 is 1:10:2-3; and the ratio of sample quantity in g to mixed solvent quantity in ml is 1:10-1:

20.

2. The method of claim 1, wherein the polynuclear condensed aromatic hydrocarbons are determined in bitumen and in petroleum fractions containing asphaltenes. In step 2, the ratio of sample quantity in g to DMSO quantity in ml is 1:20-1:

100.

3. The method for determining polycyclic aromatic hydrocarbons in asphalt and petroleum fractions containing asphaltenes according to claim 1, characterized in that: In step 3, the ratio of sample quantity in g to DMSO quantity in ml is 1:20-1:

200.

4. The method for determining polycyclic aromatic hydrocarbons in asphalt and petroleum fractions containing asphaltenes according to claim 3, characterized in that: The ratio of sample to DMSO is 1:40-1:

80.

5. The method for determining polycyclic aromatic hydrocarbons in asphalt and petroleum fractions containing asphaltenes according to claim 1, characterized in that: In step 5, the ratio of sample quantity in g to cyclohexane quantity in ml is 1:5-1:

50.

6. The method for determining polycyclic aromatic hydrocarbons in asphalt and petroleum fractions containing asphaltenes according to claim 1, characterized in that: In step 6, the ratio of sample quantity in g to cyclohexane quantity in ml is 1:2-1:

20.

7. The method for determining polycyclic aromatic hydrocarbons in asphalt and petroleum fractions containing asphaltenes according to claim 1, characterized in that: In step 7, the evaporation temperature for removing cyclohexane solvent is 80-100℃; and the vacuum drying condition is residual pressure 10-100mmHg and temperature 110-150℃.