JPH02248844A - Method and apparatus for analyzing asphaltene component in fuel oil - Google Patents

Abstract

PURPOSE:To analyze an asphaltene component quickly and handily by comparing a light scattering level in a sol between an asphaltene suspension wherein a low quality fuel oil is diluted and dissolved by n-hepthane and a complete dissolved liquid diluted at the same factor by toluene. CONSTITUTION:A low quality fuel oil of a sample tank 4 is sucked with a pump 5 and diluted and dissolved in a stirring/dissolution tank 7 about 100 times. On the other hand, n-hepthane is injected into a discharge system to be diluted about 2,000 times by capacity and a malten component alone is dissolved to make an asphaltene sol suspension. Absorbance, transmission light absorptivity and turbidity of the suspension are measured with a measuring section. Toluene is injected to other systems and diluted to the same factor as with n-hepthane to dissolve malten and asphaltene completely. The liquid thus obtained is introduced to a measuring section 2 to measure an absorbance, transmission light absorptivity and turbidity thereof. A computation output section 3 estimates an asphaltene component from a difference between measured values. With such an arrangement, an analysis value is found quickly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention rapidly removes asphaltene components from low-quality fuel oil.
The present invention also relates to a method and apparatus for conducting analysis simply and accurately.

[Conventional technology]

Asphaltene component analysis of fuel oil is generally carried out using a chemical experimental method based on the Japan Petroleum Institute method (IP143), etc. In this method, the component that is insoluble in n (normal) hebutane and soluble in toluene is It is defined as asphaltene.

This asphaltene component testing method based on the Japan Petroleum Institute method is as follows:
It is as follows.

(1) Dilute fuel oil with n-heptane on filter paper (15 times)
After that, boil under reflux for 1 hour, then boil in the dark for 1.5~2 hours.
．． Leave to cool for 5 hours. Note that the filtrate is maltene + n-heptane.

(2) Reflux-filter the substance on the filter paper with toluene for 1 hour.

(3) Reflux-filtered filtrate (asphaltene + toluene)
was placed in a container, and after evaporating the toluene on a boiling water bath, it was placed in a drying container, dried at 100-110°C for 30 minutes, and further cooled in a desiccator at 0° for 5-1 hour.
Measure the weight to determine the asphaltene component.

In addition, recently, a solution of fuel oil diluted with n-heptane,
A method has been proposed for estimating asphaltenes from the absorbance difference or absorbance ratio with a maltene solution obtained by removing floating asphaltenes from this solution.

[Problem to be solved by the invention]

When low-quality fuel oil is used, for example, in a marine engine, it is necessary to change or control the operating conditions of the engine depending on the asphaltene component in the fuel oil.

For this reason, it is required to quickly and easily analyze asphaltene components onboard ships when changing fuel oil tanks.

However, the above-mentioned Petroleum Institute method requires more than 5 to 6 hours for analysis and involves operations that are extremely difficult to automate, such as evaporation of the solvent in a boiling water bath and precise weight measurement. There is.

In addition, the method of measuring the absorbance difference or absorbance ratio using a solution prepared by diluting fuel oil with n-heptane requires consideration of the absorption wavelengths of the malten solution and the diluted solution. According to experiments, the disadvantage is that the accuracy is not very good.

The present invention was created in view of the above points, and faithfully follows the definition of asphaltene components, generates ultrafine asphaltene particles that do not settle in a short time in a sample liquid, and measures the turbidity caused by light scattering. By doing so, the aim is to replace processes that are difficult to automate, such as drying and weight measurement, with optical technology, and to provide a method and device for analyzing asphaltene components in fuel oil that are suitable for automation.

[Means to solve the problem]

The method for analyzing asphaltene components in fuel oil of the present invention involves dissolving asphaltenes in advance using toluene or xylene, etc., then generating non-sedimentable sol-like ultrafine particles, and comparing the amount of light scattering with a completely dissolved solution. This is a method for optically quantifying asphaltene components in low-quality fuel oil.

FIG. 8 shows the relationship between the absorbance of the suspension (solized liquid) and the elapsed time. Experiments were conducted on samples a, b, c, and d in a 10 m cell with a wavelength of 750 nm.

The fact that no change in absorbance is observed indicates that fine particulate asphaltene is stably suspended.

As shown in FIG. 8, the method of the present invention is based on the premise of producing sol-like asphaltene that does not precipitate.

In order to achieve the above object, the method for analyzing asphaltene components in fuel oil of the present invention uses an asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane, and the same low-quality fuel oil in toluene. The amount of light scattering is compared and measured in a sol state with a solution diluted to the same ratio as n-heptane and completely dissolved.

In addition, the method of the present invention involves diluting and dissolving low quality fuel oil with n-heptane into an asphaltene suspension, and diluting the same low quality fuel oil with toluene to the same ratio as n-heptane and completely dissolving it. The asphaltene component in the low-quality fuel oil is estimated from the light scattering (turbidity) or the difference in the transmitted light absorption rate.

Furthermore, in the method of the present invention, a turbidity difference is measured instead of a transmitted light absorption difference in the above method.

As shown in FIG. 1, the asphaltene component analysis device in fuel oil of the present invention can measure the absorbance of an asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane,
First optical measurement unit 1 that measures transmitted light absorption rate or turbidity
, a second optical measurement unit 2 for measuring the absorbance, transmitted light absorption rate, or turbidity of a liquid obtained by diluting the same low-quality fuel oil with toluene to the same ratio as n-heptane and completely melting it; Calculation/output section 3 connected to optical measurement section 1.2
This includes: Note that the calculation/output section 3 also includes a display function. 4 is a sample oil tank, 5 is a pump,
6 is a waste oil tank. 7 is a stirring dissolution tank in which asphaltene is dissolved in advance.

[Effect]

The low-quality fuel oil in the sample oil tank 4, or the oil that has been diluted with a small amount of toluene in advance to make it more fluid, is sucked in by the pump 5, and further diluted 20 to 100 times with toluene in the stirring dissolution tank 7. It is dissolved and a part of it is discharged in two lines. In one series, add n-heptane to 500~
Inject and dilute to 2000 times the volume to dissolve only the malten content to form an asphaltene sol-like suspension. This asphaltene suspension is introduced into the first optical measuring section 1, and the absorbance, transmitted light absorption rate, or turbidity is measured.

Toluene is injected into the other series at the same ratio as n-heptane and diluted to completely dissolve maltenes and asphaltenes. This liquid is transferred to the second optical measuring section 2.
to measure absorbance, transmitted light absorption, or turbidity.

The values measured by the first optical measurement unit 1 and the second optical measurement unit 2 are introduced into the calculation output unit 3, and the absorbance difference, transmitted light absorption rate difference, or turbidity difference is measured. Asphaltene component is estimated.

Generally, when diluting low-quality fuel oil with n-heptane, toluene, etc., if the dilution ratio is less than 20 times by volume, the degree of blackness of the n-heptane diluted solution and toluene diluted solution is too strong, and the difference in absorbance and transmitted light There is a disadvantage that it is not possible to determine the difference in absorption rate or the difference in turbidity.

On the other hand, if the dilution ratio exceeds 100 times the volume, it is difficult to produce a uniform asphaltene precipitate, leading to an increase in errors, and the amount of solvent used increases, which is uneconomical. For this reason, it is desirable to process the diluted treatment liquid in two stages.

〔Example〕

Hereinafter, the present invention will be explained by giving examples.

Example 1 The method of this example is a method for estimating the asphaltene content from the absorbance difference at a certain wavelength between an asphaltene suspension obtained by dissolving fuel oil in n-heptane and a solution obtained by completely dissolving fuel oil in toluene. It is.

As shown in FIG. 2, 2 g of low fuel oil was weighed in a 50-volume flask, and toluene was added until the volume reached 50+tZ. 1 ml of this was placed in another 50-proof volumetric flask, and 50-ml n-heptane was added to make up the volume (this solution is referred to as solution A).

In addition, 1- of the liquid made up of 2 g of ζ low-quality fuel oil with toluene was added to another 50-volume flask, and 5
The solution was made up by adding 0- toluene (this solution is referred to as solution B).

After thoroughly stirring liquid A and liquid B, 10++
The absorbance was measured using an a-cell at a wavelength of 750 nm, which is used in a general spectrophotometry method, and the amount of asphaltene was estimated from the difference between the absorbance of the A solution and the absorbance of the B solution.

This operation was performed on fuel oils a to e whose asphaltene content had been measured in advance. The results were as shown in Table 1.

Table 1 When these results were plotted, a graph as shown in Figure 3 was obtained. FIG. 3 shows that it is possible to accurately estimate the asphaltene content by determining the absorbance difference.

Example 2 Asphaltene components were separated, concentrated, and dried from low-quality fuel oil (d in Example 1). This asphaltene component was diluted with toluene in a range of 0.05 to 0.8% by weight to prepare an asphaltene standard solution.

This asphaltene standard solution sample was held between two transparent plates 11 and 12 made of glass, etc., as shown in FIG. 4, and the transmitted light absorption rate was measured. This result is the fifth
It was as shown in the figure. 13 is a light emitting element, 14
1 is a light receiving element, 15 is an illumination meter, 16 is a spacer, and 17 is a clip. Note that the gap between the transparent plates 11 and 12 was about 15 μm. Usually, it is desirable that this value be 10 to 20 μm.

Next, as sample 10, an asphaltene suspension was prepared by diluting several types of low-quality fuel oils with known asphaltene content (a liquid diluted 30 times by volume with toluene) to 50 times by volume with n-heptane. The rate was measured. Furthermore, the same low-quality fuel oil was diluted 50 times by volume with toluene and completely dissolved, and the transmitted light absorption rate was measured using Sample 10. The relationship between the difference in the transmitted light absorption rate and the asphaltene content was as shown in Fig. 5. From FIG. 5, it can be seen that the curve of the asphaltene standard solution and the curve of estimating the asphaltene content based on the difference in transmitted light absorption rate almost match. As the illuminance meter, an illuminance meter (manufactured by Nippon Kogaku Co., Ltd., Top Cone 3) having a standard luminous efficiency with a built-in silicon photocell was used.

Example 3 An asphaltene standard solution was prepared in the same manner as in Example 2, and as shown in FIG. 6, this solution was used as sample 10, and the turbidity was measured by sandwiching it between two transparent plates 11 and 12. did. The results were as indicated by the * mark in FIG. 16 is a spacer, 17 is a stopper, 18 is a smoke meter, 1
9 is white paper. Note that the gap between the transparent plates 11 and 12 was 25 μm. Normally, this value ranges from lO to 200 Ijm.
It is desirable to do so.

Next, as a sample 10, an asphaltene suspension prepared by diluting and dissolving several kinds of low-quality fuel oils with known asphaltene contents by 50 times the volume with n-heptane was used to measure the turbidity. Furthermore, the same low quality fuel oil was diluted 50 times by volume with toluene and completely dissolved, and the turbidity was measured using a liquid as sample 10. The relationship between these turbidity differences and asphaltene content was as shown in Figure 7. From FIG. 7, it can be seen that the curve of the asphaltene standard solution and the curve of estimating the asphaltene content based on the turbidity difference almost match. In addition,
As the smoke meter, a reflective smoke meter for measuring the concentration of exhaust smoke from diesel automobiles (manufactured by Diesel Equipment Co., Ltd., DSM-2OA) was used.

〔Effect of the invention〕

Since the present invention is configured as described above, it has the following effects.

(]) Processes that are difficult to automate in conventional methods, such as drying and weight measurement, are replaced with optical methods.
Can be easily automated.

(2) In the conventional Petroleum Institute method, it took 5 to 6 hours or more for measurement, but in the method of the present invention, drying, weight measurement, etc. are not performed, so the measurement time is significantly shortened.

(3) Extremely high measurement accuracy.

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing an example of an apparatus for analyzing asphaltene components in fuel oil according to the present invention, FIG. 2 is an explanatory diagram showing an example in which the method of the present invention is carried out by a light scattering method,
The leap is a graph showing the relationship between the absorbance difference at a wavelength of 750 rv and asphaltene, Figure 4 is a longitudinal cross-sectional explanatory diagram of the apparatus used in the example when the method of the present invention was carried out by transmitted illumination measurement method, and Figure 5 is a graph showing the relationship between the absorbance difference at a wavelength of 750 rv and asphaltene. A graph showing the relationship between absorption rate and asphaltene content, Figure 6 is a longitudinal cross-sectional explanatory diagram of the apparatus used in the example when the method of the present invention was carried out by turbidity measurement, and Figure 7 is a graph showing the relationship between turbidity and asphaltene content. FIG. 8 is a graph showing the relationship between the absorbance of a suspension (solized liquid) and elapsed time. DESCRIPTION OF SYMBOLS 1... 1st optical measurement part, 2... 2nd optical measurement part, 3... Calculation/output part, 4... Sample oil tank, 5...
... Pump, 6... Waste oil tank, 7... Stirring dissolution tank, 1... Sample, 11.12... Transparent plate, 13...
Light emitting element, 14... Light receiving element, 15... Illuminance meter, 1
6... Spacer, 17... Stopper, 18...
Smoke meter, 19...white paper fig. Le γ7Δt (Kou 19) Fig. St-7 Make No. + (1 1 ri 1 person) I Lutin # [Kou f%)

Claims (1)

[Claims] 1. An asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane and the same low-quality fuel oil diluting and dissolving with n-heptane.
- A method for analyzing asphaltene components in fuel oil, which comprises comparing and measuring the amount of light scattering in a sol state with a solution completely dissolved by diluting it to the same ratio as in the case of heptane. 2 An asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane and the same low-quality fuel oil diluting with toluene
-Measure the difference in transmitted light absorption with a liquid completely dissolved by diluting it to the same ratio as in the case of heptane, and estimate the asphaltene component in low-quality fuel oil from light scattering or this difference in transmitted light absorption. Characteristic method for analyzing asphaltene components in fuel oil. 3. The method for analyzing asphaltene components in fuel oil according to claim 2, characterized in that a turbidity difference is measured instead of a transmitted light absorption difference. 4. The first optical measuring section (1) measures the absorbance, transmitted light absorption rate, or turbidity of an asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane, and a second optical measurement section (2) that measures the absorbance, transmitted light absorption, or turbidity of a solution completely dissolved by diluting it to the same ratio as in the case of n-heptane, and these optical measurement sections (1, An apparatus for analyzing asphaltene components in fuel oil, characterized in that it includes a calculation/output section (3) connected to (2).