JPH0750100B2 - Method of measuring smoke point of fuel oil - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for measuring a smoke point of fuel oil.

In particular, the present invention relates to a method for accurately, quickly and continuously measuring the smoke point of fuel oil distilled during oil refining.

Conventional technology and problems to be solved by the invention Conventionally, when controlling and controlling the quality of fuel oil distilled in a petroleum refining process, smoke point measurement is an important and essential control and test item. It is an item.

Conventionally, for the smoke point measurement of fuel oil, the sample to be measured is collected in advance from a plant, etc. and brought into a test room, etc.
According to S K2537, ASTM D1322, IP 57-55), the length of the flame that starts to produce smoke is measured visually by the measurer (JIS K2537). This measurement method requires a large amount of time with the increase in the number of measurements when the difference in oil type or continuous measurement is required.Because the measurement method is a batch method, continuous detailed results are desired. If not, those requirements are not met.
In addition, since it is visual, there are many cases in which the measurement person also causes an individual error in the measurement result.

On the other hand, the smoke point of fuel oil is known to be governed by the concentration of unsaturated compounds contained in the fuel oil, that is, naphthin content, olefin content, aromatic content, etc., but it is not clear. Also,
Paraffin components, naphthene components, olefin components, and aromatic components, which are the general constituents of petroleum fractions, are usually quantified by column chromatography using silica gel by a method called PONA analysis. It is also known that if the viscosity and the refractive index of is known, it can be estimated by calculation.

Conventionally, the refractive index of light has been used for various measurements such as control of aromatics in a lubricating base oil, in addition to the above as a measurement method indirectly using a physical method. However, there has been no method of measuring the smoke point of fuel oil using the refractive index, and a method of accurately and continuously measuring the smoke point.

Means for Solving Problems If the above method is solved, it will make a great contribution to process control and product quality control in petroleum refining, and if it is automated, it will bring great effects in terms of labor saving and economical efficiency. be able to. As a result of earnest constitutional efforts, the inventors have reached the present invention satisfying the above requirements. That is, the inventor of the present invention has found that the smoke point of fuel oil has a correlation with the refractive index under a constant temperature, and the relationship is linear, and thus the present invention has been accomplished.

On the other hand, since the refractive index can be temperature-corrected, the smoke point of the fuel oil can be determined by measuring the refractive index of a desired fuel oil at an arbitrary temperature.

To explain the details of the process leading to the present invention, FIG. 1 shows the correlation between the smoke point measurement result of a fuel oil such as kerosene in a laboratory and the refractive index (laboratory measurement value).

As is apparent from FIG. 1, it is clear that the correlation between the smoke point and the refractive index has a very good linear relationship.
Further, when the measurement temperatures of the refractive index are different, the temperature may be corrected to the value of the refractive index shown at a predetermined temperature. Further, in an actual plant, it is easy to make the refractometer have a temperature correction function.

The correlation coefficient (R) in this case is 0.9029, which is a favorable result.

Further, as in the above, as the process control and quality control of the fuel oil in the actual plant, for example, the correlation between the smoke point of kerosene and the measurement value of the refractometer installed in the actual plant is shown in FIG. It was

As is apparent from FIG. 2, the correlation between the smoke point and the refractometer measurement value is in a very good linear relationship, as in the case of FIG. 1 described above.

The correlation coefficient (R) in this case is 0.8705, which is a preferable result. Any refractometer may be used in this case.

On the other hand, FIG. 3 shows the correlation between the laboratory measurement value and the refractive index measurement value in the actual plant for the refractive index of the same kerosene having different smoke points, such as fuel oil.

The correlation coefficient (R) in this case correlates very well with 1.0.

Therefore, it can be seen that the measured values of the refractive index in the laboratory and the measured values of the refractometer installed in the plant are in good agreement, and that there is no problem for process control or quality control in oil refining. It's obvious.

Taking into account that the laboratory measurement itself has a tolerance of ± 2.0 mm (JIS K2537 standard) for repeated measurement,
It can be seen that the smoke point of fuel oil can be measured rapidly and continuously with sufficient accuracy than the refractive index measured at a predetermined temperature.

Examples The present invention will be described in detail below with reference to examples, but the invention is not limited thereto.

Example 1 As shown in FIG. 4, in a petroleum refining process, a water cooler 5 and a refractometer 6 are provided in series with a sample line 4 provided in a conduit from the kerosene stripper 1 (system without a circulation pump).

Since the refractometer has a temperature correction function added, the temperature of kerosene (sample) may be set to a specified temperature ± 0.5 ° C with a water cooler, but it is ± 30 ° C of the measurement temperature described in the test method. ℃
If it is set so that the range is within a certain range, the smoke point of kerosene can be continuously and accurately measured. Of course, the conversion of the obtained refractive index measurement value into a smoke point is calculated by a computer.

In FIG. 4, 1 is a kerosene stripper, 2 is a heat exchanger for fuel oil, 3 is a sample circulation line, 4 is a sample line, 5 is a water cooler, and 6 is a refractometer. LC is a liquid level control device and RO is an orifice.

Example 2 As shown in FIG. 5, in a petroleum refining process, a sample circulation pump 7, a water cooler and a refractometer 6 are provided in series with a sample line 4 provided in a conduit coming out of a kerosene stripper 1. Type system).

As in the case of Example 1, since the refractometer has a temperature correction function, the temperature of kerosene (sample) may be set to a predetermined measurement temperature ± 0.5 ° C. with a water cooler. If the temperature is set within ± 30 ° C of the measurement temperature described in, the smoke point of kerosene can be measured continuously and accurately. The circulation pump installed system is particularly useful when a differential pressure cannot be obtained between the sample intake port and the return port.

In FIG. 5, 1 is a kerosene stripper, 2 is a sample line, 3 is a sample circulation line, 4 is a sample line, 5 is a water cooler, 6 is a refractometer, and 7 is a sample circulation pump. LC and RO are the same as in FIG.

Advantages of the Invention (1) There is no dependence on the measuring instrument and the measured value depending on the oil type.

(2) The measured value follows the measured value of the smoke point well even when the operating conditions of the treated oil are changed.

(3) The accuracy is equal to or higher than the accuracy specified in the test method.

(4) It is possible to measure quickly and continuously.

(5) Management costs can be significantly reduced.

(6) Labor saving can be achieved.

(7) Increased production of fuel oil becomes easy.

[Brief description of drawings]

Fig. 1 is a graph showing the correlation between the smoke point of kerosene and the refractive index (laboratory measured value), and Fig. 2 is the smoke point of kerosene in an actual plant and the refractometer installed in the actual plant. Fig. 3 is a graph showing the correlation with the measurement value of Fig. 3, and Fig. 3 is a graph showing the correlation between the refractive index of kerosene (laboratory measurement value) and the refractive index measurement value of an actual plant. FIG. 4 is an explanatory diagram showing a smoke point measuring method, and FIG. 5 is another explanatory diagram showing a smoke point measuring method (when a sample circulation pump is used together). In FIGS. 4 and 5, 1 ... Kerosene stripper, 2 ... Heat exchanger, 3 ... Sample circulation line, 4 ... Sample line, 5 ... Water cooler, 6 ... Refractometer, 7 ... … Sample circulation pump, LC… Liquid level control device, RO… Orifice.

Claims (1)

[Claims] 1. The smoke point of the fuel oil and the refractive index have a linear relationship at a constant temperature, and therefore the smoke point of the fuel oil is determined by measuring the temperature and the refractive index of the fuel oil. Measuring method of fuel oil smoke point.