JPH0421135B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for measuring the clogging point of petroleum products such as light oil, and more specifically, to a method for accurately and automatically measuring the clogging point of petroleum products containing pour point depressants. Regarding how it can be done. Conventional Technology Conventionally, when automatically measuring the clogging point (CFPP) of petroleum products such as light oil in order to evaluate their low-temperature fluidity, a clogging point meter as shown in Fig. 3 is usually used. That is, in the clogging point meter shown in FIG. 3, the sample liquid 2 is introduced into the clogging point 1,
This is a measurement cell disposed on a cooler 3 for cooling a sample liquid 2. Reference numeral 4 denotes a suction tube whose tip side is immersed in the sample liquid 2 in the cell 1. The tip of the suction tube 4 reaches near the bottom of the cell 1, and the large diameter portion 4a of the tip is provided with a tube that covers the opening. A filter 5 of a predetermined mesh is attached. In addition, the proximal end side of the suction tube 4 protrudes outside the cell 1, and the proximal end has a connecting tube 7 connected to the suction mechanism 6.
The ends of the tubes are connected to each other, and a liquid level detector 10 for detecting the sample liquid 2 rising inside the suction tube 4 consisting of a lamp 8 and a photoelectric sensor 9 is arranged near the base end. ing. Furthermore, 11 is a temperature sensor installed through the side wall of the cell 1 and whose detection end is arranged near the lower end of the suction pipe 4,
This temperature detector 11 is designed to detect the temperature of the sample liquid 2 flowing into the suction tube 4. Although not shown, a sample liquid introduction pipe and a sample liquid discharge pipe are connected to the cell 1, respectively. When measuring the clogging point of a sample liquid using the clogging point meter, first, the sample liquid 2 from the previous measurement in cell 1 is removed through the sample liquid discharge pipe, and at the same time, it is introduced into cell 1 from the sample liquid inlet pipe. A predetermined amount of sample liquid 2 to be measured is introduced. next,
The sample liquid 2 is cooled by the cooler 3 at a predetermined cooling rate, and each time the sample liquid temperature drops, for example, by one degree, the suction mechanism 6 is operated to suck the inside of the suction tube 4 at a predetermined suction pressure (200 mm water column). While the sample liquid 2 has fluidity, the sample liquid 2 passes through the filter 5, ascends the suction tube 4, and is sucked up to the position of the photoelectric sensor 9, but as the temperature of the sample liquid 2 decreases, it loses its fluidity. Then, the sample liquid 2 becomes difficult to pass through the filter 5, and finally does not rise to the position of the photoelectric sensor 9. Sample liquid 2 when this rise stops
The temperature is detected by the temperature detector 11, and this is used as the clogging point (CFPP) value. Problems to be Solved by the Invention However, the sample liquid 2 in the cell 1 is sucked through the suction tube 4, and the sample liquid 2 rises.
Conventional clogging point meters that measure the clogging point by detecting the liquid level have had the following problems. That is, in the conventional clogging point meter, when the sample liquid 2 rises in the suction tube 4 due to suction and the liquid level is detected by the liquid level detector 10, suction is stopped at that stage and the suction tube 4 Sample liquid 2 in cell 1
The next suction is started when the sample liquid 2 is cooled to a predetermined temperature. However, if the sample liquid 2 contains a pour point depressant, the suction is started after the liquid level is detected. Even if the suction force is released, a phenomenon occurs in which the sample liquid 2 in the suction tube 4 does not return sufficiently into the cell 1, and especially at temperatures near the clogging point, the sample liquid 2 hardly flows even if the suction force is released. Therefore, when measuring the clogging point of the sample liquid 2 containing a pour point depressant, when the clogging point is near, the next suction is performed before the liquid level of the sample liquid 2 in the suction tube 4 has fallen sufficiently. Therefore, the liquid level reaches the position of the liquid level detector 10 immediately after the start of suction, and the liquid level is detected before the predetermined amount of sample liquid 2 passes through the filter 5. Even if the temperature is quite low, the sample solution 2
As a result, the measured clogging point becomes abnormally lower in temperature than the actual clogging point, making it impossible to accurately measure the clogging point. Such inconveniences can be avoided by visually observing the flow of the sample liquid in the case of manual analysis, but it is difficult to visually observe the flow state of the sample liquid with automatic process analyzers. For this reason, there has been a desire for a method that can accurately and automatically measure the clogging point of a sample liquid containing a pour point depressant. The present invention was developed in view of the above circumstances, and when the temperature of light oil containing a pour point depressant reaches near the clogging point, even if the suction is canceled, there is still enough water to flow from the suction pipe through the filter into the cell. It is an object of the present invention to provide a clogging point measuring method that can accurately measure the clogging point of a sample liquid, which is difficult to accurately measure the clogging point by the method of detecting the liquid level. shall be. Means and action for solving the problem That is, the present inventors found that a sample liquid such as light oil to which a pour point depressant was added hardly flows even when the suction force is removed near the clogging point detection temperature. Also, during suction, the sample liquid in the measurement cell flows into the suction tube from the bottom through the filter, but the sample liquid in the cell is cooled sequentially from the bottom by the cooling device. , this sample liquid becomes colder as it goes to the bottom, so it is important to note that the sample liquid that passes through the filter during suction becomes hotter as the suction progresses, and the sample liquid is close to the clogging point detection temperature. In this case, the sample liquid in the suction tube does not return much into the cell, so even if suction is performed, almost no sample liquid passes through the filter between the start of suction and the time of liquid level detection. The present invention has been made based on the discovery that the temperature of the sample liquid when the temperature rises during this period becomes less than or equal to a preset amount can be recognized as the clogging point. I've reached it. Therefore, the present invention cools the sample liquid in the measurement cell at a predetermined cooling rate with a cooling device, inserts a suction tube with a filter attached to the tip into the sample liquid, and cools the sample liquid in the measurement cell. is intermittently sucked into the suction tube through the filter at a predetermined suction pressure for a predetermined period of time, and when a predetermined amount of sample liquid has passed through the filter, the suction is released, and the sample liquid in the suction tube is returned to the measurement cell. In the clogging point measurement method, which detects the clogging point from the relationship between the liquid passing through the filter and the temperature of the sample liquid, the amount of temperature rise of the sample liquid passing through the filter during suction is detected, and this temperature rise is determined by a predetermined amount. The clogging point is defined as the temperature of the sample liquid when the temperature falls below. In the present invention, the amount of temperature rise of the sample liquid passing through the filter is detected, and the clogging point is determined based on whether or not this amount of temperature rise has become less than a predetermined amount. Unlike the case of measuring the clogging point, the clogging point can be accurately measured regardless of whether or not the sample liquid returns to the cell when suction is released. The present invention will be explained in more detail below. FIG. 1 shows an example of a clogging point meter used in carrying out the method of the present invention. In FIG. 1, parts having the same configuration as those in the device in FIG. 3 are given the same reference numerals and their explanations are omitted. However, unlike the device in FIG. 3, this device has a lamp 8 and a photoelectric sensor 9. A liquid level detector 10 consisting of the following is not provided. When measuring the clogging point of the sample liquid using the clogging point meter of this example, the cell 1
The sample liquid 2 introduced into the tube is cooled at a predetermined cooling rate by the cooler 3, and each time the sample liquid temperature drops by a predetermined temperature (for example, 1°C), the suction mechanism 6 is operated to raise the suction pressure inside the suction tube 4 to a predetermined suction pressure. (200mm water column)
The temperature rise of the sample liquid 2 passing through the filter 5 during this suction is detected, and if this temperature rise is larger than a preset amount, the suction is canceled and the sample liquid 2 passes through the filter 5. The sample liquid 2 is returned into the cell 1, and the temperature of the sample liquid 2 when the temperature drops below the predetermined amount is determined as the clogging point. That is, as mentioned above, the sample liquid 2 in the cell 1
The temperature is lower at the bottom and higher at the top, but if the sample liquid temperature is much higher than the clogging point, most of the sample liquid 2 in the suction tube 4 will return to the cell 1 when the suction is released, and the next Since this sample liquid 2 passes through the filter 5 during suction, the amount of temperature rise of the sample liquid 2 passing through the filter 5 is large, as shown in FIG. 2a. On the other hand, as the sample liquid temperature approaches the clogging point, the amount of sample liquid returned to the cell 1 when suction is released decreases, so the amount of sample liquid that passes through the filter 5 during the next suction decreases. The amount of temperature rise of the sample liquid passing through the filter 5 also gradually decreases as shown in b to c in Fig. 2, and when the sample liquid temperature reaches the clogging point detection temperature, the amount of temperature rise is shown in Fig. 2 d. becomes smaller than the predetermined amount Tr. Therefore, by detecting the temperature of the sample liquid 2 at this time, the clogging point (CFPP) can be measured. In this case, the predetermined amount (temperature rise test width) Tr used to determine the clogging point can be selected as appropriate depending on the type of sample liquid, etc., but is usually 0 to 1.0°C.
It is preferable to set the value within the range of 0.001 to 0.000, thereby making it possible to accurately measure the clogging point. Therefore, according to the present invention, the clogging point can be measured regardless of whether or not the sample liquid 2 in the suction tube 4 returns to the cell 1 when the suction is released. It is also possible to accurately and automatically measure clogging points such as the following. In addition, in the above embodiment, the temperature detector 11
Although the clogging point was measured only by detecting the temperature change of the sample liquid 2 passing through the filter 5, a liquid level detector 10 was provided as in the clogging point meter shown in FIG. The clogging point may be measured by appropriately combining the signal from the temperature detector 11 and the signal from the liquid level detector 10 depending on the type of the liquid. Next, the effects of the present invention will be specifically illustrated through experimental examples. Experimental Example Using the clogging point meter shown in FIG. 1, the clogging point (CFPP) of light oil (samples A to C) to which a pour point depressant was added was measured by the above-described method of the present invention. In this case, the temperature rise detection width Tr is 0°C,
The sample liquid temperature Ts at the start of the measurement was 0°C, the measurement interval Tw was 1°C, and the suction time j was 60 seconds (see Figure 2). In addition, for comparison, a manual analysis method using the filtration clogging point test method based on 1P-309 and a third
The clogging points of the same samples were measured using the above-described liquid level detection method using the conventional clogging point meter shown in the figure. The results are shown in Table 1.

[Table] From the results in Table 1, the measured values obtained by the method of the present invention agree well with the manual analysis values, and therefore, according to the present invention, the clogging point of light oil to which a pour point depressant has been added can be accurately measured. It is recognized that On the other hand, when detected using the conventional liquid level detection method, the clogging point was detected as a significantly lower value than the manual analysis value. Effects of the Invention As explained above, according to the method for measuring the clogging point according to the present invention, the clogging point can be measured not only for ordinary light oil and A heavy oil but also for cases where a pour point depressant is added to these oils. It is possible to accurately measure the clogging point of a sample containing such a pour point depressant, and to obtain a measurement value that is almost the same as a manual analysis value.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional schematic diagram showing an example of a clogging point meter used in carrying out the present invention, Fig. 2 is a graph showing the measurement principle of the method of the present invention, and Fig. 3 shows a conventional clogging point meter. It is a partial cross-sectional schematic diagram. 1... Measurement cell, 2... Sample liquid, 3... Cooler, 4... Suction tube, 5... Filter, 6... Suction mechanism.

Claims (1)

[Claims] 1. The sample liquid in the measurement cell is cooled at a predetermined cooling rate by a cooling device, and a suction tube with a filter attached to the tip is inserted into the sample liquid, and the sample liquid in the measurement cell is intermittently passed through the filter. When a predetermined amount of sample liquid has passed through the filter, the suction is released and the sample liquid in the suction tube is returned to the measurement cell, and the sample liquid passes through the filter and the sample is removed. In the clogging point measurement method, which detects the clogging point from the relationship with the temperature of the liquid,
A clogging point characterized in that the temperature rise of the sample liquid passing through the filter during suction is detected, and the temperature of the sample liquid when this temperature rise falls below a predetermined amount is set as the clogging point. How to measure.