JPH0643959B2 - Method and apparatus for analyzing asphaltene components in fuel oil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is intended to rapidly remove asphaltene components in low-quality fuel oil,
In addition, the present invention relates to a method and an apparatus for performing simple and accurate analysis.

[Conventional technology]

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

Asphaltene component test method by this Petroleum Institute method,
It is as follows.

(1) The fuel oil is diluted (15 times) with n-heptane on a filter paper, boiled under reflux for 1 hour, and then left to cool in the dark for 1.5 to 2.5 hours. The filtrate is martens + n-heptane.

(2) The substance on the filter paper is reflux-filtered with toluene for 1 hour.

(3) After receiving the filtrate (asphaltene + toluene) filtered under reflux in a container and removing the toluene by evaporation on a boiling water bath,
It is put in a drier, dried at 100 to 110 ° C. for 30 minutes, and allowed to cool in a desiccator for 0.5 to 1 hour, and then weighed to obtain an asphaltene component.

Also, recently, a solution obtained by diluting fuel oil with n-heptane,
A method has been proposed in which asphaltene is estimated from the difference in absorbance or the absorbance ratio with a marten solution obtained by removing floating asphaltene from this solution.

[Problems to be Solved by the Invention]

When low-quality fuel oil is used in, for example, a marine engine, it is necessary to change / adjust the operating condition of the engine by the asphaltene component in the fuel oil. Therefore, when the fuel oil tank is switched, it is required to analyze the asphaltene component onboard the ship quickly and easily.

However, the above-mentioned Petroleum Institute method takes 5 to 6 hours or more for analysis, and when it is automated, it involves operations that are very difficult to automate, such as evaporation removal of solvent on a boiling water bath and precise weight measurement. There is.

Further, the method of measuring the absorbance difference or the absorbance ratio using the solution obtained by diluting the fuel oil with n-heptane needs to take the absorption wavelengths of the marten solution and the diluted solution into consideration. According to the method, there is a disadvantage that the accuracy is not so good.

The present invention has been made in view of the above points, and in accordance with the definition of the alfartene component, ultrafine particles of asphaltene that does not sediment in a short time are generated in the sample liquid, and turbidity due to light scattering thereof is generated. An object of the present invention is to provide a method and an apparatus for analyzing asphaltene components in fuel oil, which are suitable for automation, by replacing processes that are difficult to automate, such as drying and weighing, with optical technology by weighing.

[Means for Solving the Problems]

The method for analyzing the asphaltene component in fuel oil of the present invention is to dissolve asphaltene with toluene, xylene or the like in advance, and then generate non-sedimentation sol-like ultrafine particles to compare the amount of light scattering with the amount of light scattering. 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 (sol solution) and the elapsed time. Sample a with a wavelength of 750 nm and a cell of 10 mm
Experiments were conducted on b, c and d. The fact that there is no change in the absorbance indicates that the particulate asphaltene is stably floating.

The method of the present invention is premised on producing sol-like alfaltenes that do not settle, as shown in FIG.

In order to achieve the above object, the method for analyzing asphaltene components in fuel oil according to the present invention comprises: an asphaltene suspension prepared by diluting and dissolving a low-quality fuel oil with n-heptane; -The amount of light scattering is measured by contrast with a solution obtained by diluting at the same magnification as heptane and completely dissolved, in a sol state.

In addition, the method of the present invention comprises a asphaltene suspension prepared by diluting and dissolving low-quality fuel oil with n-heptane, and the same low-quality fuel oil is diluted with toluene to the same ratio as in the case of n-heptane to completely dissolve it. The asphaltene component in low quality fuel oil is estimated from the difference in transmitted light absorptivity with the liquid and scattering of light (turbidity) or the difference in the transmitted light absorptivity.

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

Then, the apparatus for asphaltene component analysis in fuel oil of the present invention, as shown in FIG. 1, the absorbance of the asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane,
First optical measuring unit 1 for measuring transmitted light absorption rate or turbidity
And a second optical measuring unit 2 for measuring the absorbance, transmitted light absorptivity or turbidity of a liquid obtained by diluting the same low-quality fuel oil with toluene to the same magnification as in the case of n-heptane and completely dissolving it. Calculation / output unit 3 connected to the optical measuring units 1 and 2
And include. The calculation / output unit 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 and dissolving tank for preliminarily dissolving asphaltene.

[Action]

The low-quality fuel oil in the sample oil tank 4 or the low-quality fuel oil previously diluted with a small amount of toluene to facilitate fluidization is sucked by the pump 5, and further diluted with toluene 20 to 100 times in the stirring and dissolving tank 7. It is melted and a part thereof is discharged in two lines. One series is n-heptane 500-200 of low quality fuel oil
It is injected and diluted so that it becomes 0 volume times, and only the maltene content is dissolved to obtain an asphaltene sol suspension. This asphaltene suspension is introduced into the first optical measurement unit 1 to measure the absorbance, transmitted light absorptance or turbidity.

Toluene is poured into the other series at the same magnification as in the case of n-heptane and diluted to completely dissolve martens and asphaltene. This liquid is used as the second optical measurement unit 2
Then, the absorbance, transmitted light absorption rate or turbidity is measured.

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 difference in absorbance, the difference in transmitted light absorptance, or the difference in turbidity is measured. The asphaltene component is estimated from this.

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 the toluene diluted solution is too strong, the difference in absorbance, the transmitted light. There is an inconvenience that the difference in absorption rate or the difference in turbidity cannot be obtained.

On the other hand, when the dilution ratio exceeds 100 times by volume, it is difficult to form a uniform asphaltene precipitate, which leads to an increase in error and the amount of solvent used increases, which is uneconomical. Therefore, it is desirable to treat the diluted treatment liquid in two stages.

〔Example〕

 Examples of the present invention will be described below.

Example 1 The method of this example is a method of estimating the asphaltene content from the difference in absorbance at a certain wavelength between an asphaltene suspension in which fuel oil is dissolved in n-heptane and a liquid in which fuel oil is completely dissolved in toluene. Is.

As shown in FIG. 2, 2 g of low-quality fuel oil was weighed in a 50-m volumetric flask, and toluene was added until the volume became 50 m to make the volume up. 1 m of this was put into another 50 m volumetric flask, and 50 m of n-heptane was added to make up the volume (this liquid is referred to as liquid A).

Further, 1 m of the liquid obtained by measuring up 2 g of low-quality fuel oil with toluene was placed in another 50 m measuring flask, and 50 m of toluene was added to measure up (this liquid is referred to as liquid B).

After thoroughly agitating each of solution A and solution B, measure the absorbance at a wavelength of 750 nm, which is used in general absorptiometry in a 10 mm cell, and estimate the amount of asphaltene from the difference between the absorbance of solution A and that of solution B. did. This operation was performed for the fuel oils a to e whose asphaltene content was previously measured. The results are shown in Table 1.

When this result was plotted, a graph as shown in FIG. 3 was obtained. From FIG. 3, it is understood that the asphaltene content can be accurately estimated by obtaining the difference in absorbance.

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

As shown in FIG. 4, this asphaltene standard solution sample 10 was held between two transparent plates 11 and 12 such as glass, and the transmitted light absorptance was measured. This result is the fifth
It was like the mark ● in the figure. 13 is a light emitting element, 14
Is a light receiving element, 15 is an illuminometer, 16 is a spacer, and 17 is a pincer. The gap between the transparent plates 11 and 12 is about
It was 15 μm. Generally, it is desirable that this value be 10 to 20 μm.

Next, several kinds of low-quality fuel oils having a known asphaltene content (a liquid diluted 30 times by volume with toluene) were diluted 50 times by volume with n-heptane and dissolved to obtain a sample 10 and absorbed as transmitted light. The rate was measured. Further, the same low-quality fuel oil was diluted 50 times by volume with toluene and completely dissolved, and the liquid 10 was used as a sample 10 to measure the transmitted light absorption rate. The relationship between the difference in transmitted light absorptance and the asphaltene content was as indicated by ∘ in FIG. It can be seen from FIG. 5 that the curve of the asphaltene standard solution and the curve of the asphaltene content estimated from the difference in the transmitted light absorptance are substantially the same. As the illuminance meter, an illuminance meter (top cone IM-3 manufactured by Nihon Kogaku Co., Ltd.) having a standard relative 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 this solution was used as sample 10 and held between two transparent plates 11 and 12 to measure the turbidity. did.
The results are as shown by ● in FIG. 16 is a spacer, 17 is a pincer, 18 is a smoke meter,
Reference numeral 19 is white paper. The gap between the transparent plates 11 and 12 was 25 μm. Generally, it is desirable that this value be 10 to 200 μm.

Next, the turbidity was measured using Sample 10 as an asphaltene suspension in which several types of low-quality fuel oils having known asphaltene contents were diluted 50 times by volume with n-heptane and dissolved. Further, the same low-quality fuel oil was diluted 50 times by volume with toluene and completely dissolved, and the liquid was completely dissolved. The relationship between these turbidity differences and asphaltene content is
It was like ▲ in FIG. 7. It can be seen from FIG. 7 that the curve of the asphaltene standard solution and the curve of the asphaltene content estimated by the difference in turbidity are almost the same. As the smoke meter, a reflection type smoke meter for measuring the exhaust smoke concentration of a diesel vehicle (DSM-20A manufactured by Diesel Instruments Co., Ltd.) was used.

[Advantages of the Invention] Since the present invention is configured as described above, it has the following advantages.

(1) Since the steps that are difficult to automate such as drying and weight measurement in the conventional method are replaced by the optical method, the steps can be easily automated.

(2) In the conventional method of the Japan Petroleum Institute, the measurement took 5 to 6 hours or more, but in the method of the present invention, the measurement time is greatly shortened because the drying / weight measurement is not performed.

(3) The measurement accuracy is extremely high.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an embodiment of an asphaltene component analyzer for fuel oil of the present invention, and FIG. 2 is an explanatory view showing an embodiment when the method of the present invention is carried out by a light scattering method.
FIG. 4 is a graph showing the relationship between the absorbance difference at a wavelength of 750 nm and asphaltene, FIG. 4 is a vertical cross-sectional explanatory view of the apparatus used in the example when the method of the present invention was carried out by a transmitted illuminance measurement method, and FIG. Fig. 6 is a graph showing the relationship between absorption rate and asphaltene content, Fig. 6 is a longitudinal cross-sectional explanatory view of the apparatus used in the example when the method of the present invention was carried out by a turbidity measuring method, and Fig. 7 is turbidity and asphaltene. Fig. 8 is a graph showing the relationship with the minutes, and Fig. 8 is a graph showing the relationship between the absorbance of the suspension (sol solution) and the elapsed time. DESCRIPTION OF SYMBOLS 1 ... 1st optical measurement part, 2 ... 2nd optical measurement part, 3 ... Computation / output part, 4 ... Sample oil tank, 5 ... Pump, 6 ... Waste oil tank, 7 ... Stirring dissolution tank, 10 ... Sample, 11, 12 ... Transparent plate, 13 ... Light emitting element, 14 ... Light receiving element, 15 ... Illuminance meter, 16 ... Spacer, 17 ... Stopper, 18 ... Smoke meter, 19 ... White paper

Claims (4)

[Claims] 1. An asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane, and a liquid obtained by diluting the same low-quality fuel oil with toluene to the same ratio as in the case of n-heptane and completely dissolving it. A method for analyzing asphaltene components in fuel oil, which comprises measuring the amount of light scattering in a sol state. 2. An asphaltene suspension obtained by diluting and dissolving low-quality fuel oil with n-heptane, and a liquid obtained by diluting the same low-quality fuel oil with toluene to the same ratio as in the case of n-heptane and completely dissolving it. A method for analyzing asphaltene components in fuel oil, characterized by measuring the difference in transmitted light absorptivity of the fuel oil and estimating the asphaltene component in the low quality fuel oil from the scattering of light or the difference in the transmitted light absorptance. 3. The method for analyzing asphaltene components in fuel oil according to claim 2, wherein a difference in turbidity is measured instead of the difference in transmitted light absorptance. 4. The same low quality fuel as the first optical measuring section (1) for measuring the absorbance, transmitted light absorptance or turbidity of an asphaltene suspension obtained by diluting and dissolving a low quality fuel oil with n-heptane. Second optical measurement unit (2) for measuring the absorbance, transmitted light absorptance or turbidity of a liquid obtained by completely diluting oil with toluene at the same magnification as in the case of n-heptane, and these optical measurements. A device for analyzing asphaltene components in fuel oil, comprising an arithmetic / output unit (3) connected to the units (1, 2).