JP6016764B2 - Ester oil evaluation device and evaluation method - Google Patents

Description

  The present invention relates to an ester oil evaluation apparatus and an evaluation method used for, for example, hydraulic oil.

  For example, ester oil used for hydraulic oil or the like is synthesized by esterification reaction (dehydration reaction) using alcohol and fatty acid as raw materials. This ester oil is hydrolyzed in a water environment, that is, the reverse reaction of the esterification reaction occurs reversibly and decomposes into alcohol and fatty acid. Since the life of the ester oil is managed by examining the total acid value of the oil, the generation of fatty acids by hydrolysis shortens the oil life.

  Conventionally, the evaluation of hydrolysis stability of ester oil is performed in a beverage container test shown in ASTM D2619 (Standard Test Method for Hydrodynamic Stability of Hydrodynamic Fluids). This test method according to ASTM D2619 is to put 75 g of ester oil, 25 g of water and a copper plate in a beverage container and shake for 48 hours under the condition of 93 ° C., change the total acid value of the oil by shaking, The weight change and appearance of the copper plate are evaluated (Non-Patent Document 1).

ASTM D2619

However, the prior art ASTM D2619 test method has the following problems.
That is, in the ASTM D2619 test method, water is added in a large amount of 25% to ester oil, so that the oil layer and the water layer are separated. Then, by shaking the beverage container, a water-in-oil emulsion is formed, and the oil layer is considered to have a saturated moisture concentration of the ester oil.

Here, the saturated moisture concentration shows different values depending on the ester oil, and is in the range of about 500 ppm to 5000 ppm. Since the hydrolysis rate is considered to depend on the moisture concentration in the oil, the hydrolysis rate will be different if the saturated moisture concentration is different.
As a result, it is considered that it is not suitable to evaluate the hydrolysis stability of oils having different saturated water concentrations side by side by the method of ASTM D2619 in which water is added excessively.

  The hydrolysis of the ester oil is considered to occur in the oil or at the interface between the oil and water. The reaction rate in oil is considered to be affected by the saturated water concentration as described above, but the interface between the oil and water is considered to have approximately the same surface area if the shaking conditions are the same. The impact of is considered to be small.

  Furthermore, since the ASTM D2619 test method is performed by adding a large amount of water to the ester oil, the test is different from the one in which hydrolysis stability is evaluated with a water concentration (for example, 1000 ppm or less) simulating an actual machine. There is a problem that data consistent with the oil life of the actual machine cannot be acquired.

  In addition, the water concentration of the biodegradable hydraulic fluid for construction machinery is determined to be 1000 ppm or less for new oil, and it is generally not used at a water concentration at which water droplets are generated in the oil in operation. On the other hand, the ASTM D2619 test method has a problem that it does not assume an actual machine because it is hydrolyzed using a large amount of water.

  Therefore, the appearance of an ester oil evaluation device and an evaluation method that can easily acquire data consistent with the oil life of an actual machine regarding the hydrolytic stability of oils having different saturated water concentrations is desired.

  In view of the above problems, the present invention provides an ester oil evaluation device and an evaluation method that can easily acquire data consistent with the actual oil life of hydrolysis stability of oils having different saturated water concentrations. This is the issue.

  The first invention of the present invention for solving the above-described problems includes a sealed container that holds and holds a predetermined amount of ester oil, and a heating device that heats the ester oil in the sealed container to hydrolyze the ester oil. A trace moisture analyzer that measures a trace amount of water in the sealed container, a trace moisture adder that adds a trace amount of moisture into the sealed container, and the sealed container according to the measurement result of the trace moisture analyzer And a moisture concentration control device for maintaining the moisture content of the ester oil at a predetermined concentration.

  According to a second aspect of the present invention, there is provided the ester oil evaluation apparatus according to the first aspect, wherein the hydrolysis is performed when the water content at the predetermined concentration is equal to or less than the saturated water content of the ester oil.

  A third invention is an ester oil evaluation device according to the first or second invention, wherein the trace moisture adding device is a moisture supply device provided with a microsyringe.

  In a fourth aspect of the present invention, a predetermined amount of ester oil is hermetically held in a sealed container, a trace amount of water in the sealed container is measured, and the ester oil in the sealed container is measured according to the measurement result of the trace amount of moisture. The method for evaluating an ester oil is characterized in that water is added, the amount of dissolved water in the ester oil is controlled to a predetermined concentration, and hydrolysis is performed while heating for a predetermined time.

  According to a fifth aspect of the invention, there is provided the ester oil evaluation method according to the fourth aspect of the invention, wherein the hydrolysis is performed when the water content at the predetermined concentration is equal to or less than the saturated water content of the ester oil.

  A sixth invention is the method for evaluating an ester oil according to the fourth or fifth invention, wherein the total acid value of the ester oil is measured after the predetermined time has elapsed.

  According to the present invention, it is possible to easily obtain data consistent with the oil life of an actual machine regarding the hydrolytic stability of oils having different saturated water concentrations.

FIG. 1 is a schematic diagram of an ester oil evaluation apparatus according to an embodiment. FIG. 2 is a diagram showing an example in which three types of oil A, oil B, and oil C are tested. FIG. 3 is a diagram showing the relationship between the moisture content and the deterioration of the ester oil.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

FIG. 1 is a schematic diagram of an ester oil evaluation apparatus according to an embodiment.
As shown in FIG. 1, the ester oil evaluation apparatus 10 according to the present embodiment heats the ester oil 11 in the hermetic container 12 by heating the ester oil 11 in the hermetic container 12 by holding the ester oil 11 hermetically sealed in a predetermined amount. A heating device 13 for hydrolysis, a trace moisture analyzer 14 for measuring a trace amount of water in the sealed container 12, a trace moisture addition device 16 for adding a trace amount of moisture 15 in the sealed container 12, and a trace moisture analyzer 14 And a moisture concentration control device 17 that maintains the moisture content of the ester oil 11 in the hermetic container 12 at a predetermined concentration. In FIG. 1, reference numeral 20 indicates a stirring device that stirs the ester oil 11 in the sealed container 12.

In the present invention, hydrolysis is performed at a moisture concentration equal to or lower than the saturated moisture concentration of the ester oil 11, and the ester oil is evaluated.
Examples of ester oils include phosphate esters and fatty acid esters used as control system oils for steam turbines, fatty acid esters and propylene glycol monoether (PAG) used for wind turbine hydraulic oil, etc. The invention is not limited to this.

Specifically, a case where the water concentration is managed to 500 ppm, for example, will be described.
First, 500 g of ester oil is introduced into the sealed container 12, and the water content at this time is confirmed by the trace water analyzer 14.

And when managing to 500 ppm, it is necessary to hold | maintain to the water content of 500gx500 / 1000000 = 25/100 = 0.25g = 250mg.
For example, when the moisture concentration is managed at 500 ppm ± 20 ppm, for example, if it is to be managed in increments of 2 ppm, the addition of the moisture 15 added from the trace moisture adding device 16 requires the addition in increments of 1 mg.

  This water addition can be achieved by using a trace water addition device such as a micro syringe.

Then, the water concentration is controlled at 500 ppm ± 20 ppm, and hydrolysis is performed with the heating device 13 at a predetermined temperature (for example, about 90 ° C.) for a predetermined time.
The heating temperature may be approximately the same as the temperature of the usage state of the ester oil, or the temperature may be increased to promote hydrolysis and an accelerated test may be performed. The airtight container needs to have pressure resistance according to the water vapor pressure of the test temperature, but when the airtight container is a pressure container, it is possible to test at a temperature exceeding 100 ° C.

  Since water is consumed during the hydrolysis, it is monitored at a predetermined time using the trace moisture analyzer 14 and is managed by the moisture concentration controller 17 so that the moisture concentration is always 500 ppm ± 20 ppm. The moisture 15 may be appropriately supplemented from the trace moisture adding device 16 as appropriate. In addition, the trace moisture analyzer 14 performs analysis by sucking a predetermined amount of the ester oil 11 in the sealed container 12. In the present embodiment, it is set to 500 ppm ± 20 ppm, which is an example. In order to increase the accuracy of the test, the allowable range may be narrowed to ± 10 ppm. Here, as the moisture analyzer, a moisture test method (Karl Fischer method) defined by JISK2275, a known moisture sensor, or the like is applied as the moisture concentration.

The predetermined time for the predetermined time of hydrolysis is appropriately set according to, for example, 500 hours, 1000 hours, and 2000 hours, and the degree of deterioration due to oil hydrolysis.
In the evaluation, a side-by-side evaluation of the hydrolysis stability of the ester oil may be performed by performing a test under the same conditions (water content, heating temperature, hydrolysis time).

In the method for evaluating an ester oil according to the present invention, first, an ester oil to be tested is prepared, and a predetermined amount is hermetically held in a sealed container 12. Next, the trace moisture content in the sealed container 12 is measured by the trace moisture analyzer 14, and the moisture 15 is supplied to the ester oil 11 in the sealed container 12 from the trace moisture addition device 16 according to the measurement result of the trace moisture content. In addition, the hydrolysis is performed while heating for a predetermined time while managing the dissolved water content in the ester oil 11 at a predetermined concentration (for example, 500 ppm ± 20 ppm).
The total acid value, kinematic viscosity, and RPVOT value (Rotating Pressure Vessel Oxidation Test) of the ester oil hydrolyzed for this predetermined time are measured to determine the degree of deterioration. Further, the appearance of the ester oil 11 may be observed and evaluated.
As a result, it is possible to easily obtain data consistent with the actual oil life for the hydrolytic stability of oils with different saturated water concentrations.

  FIG. 2 is a diagram showing an example in which three types of oil A, oil B, and oil C are tested. It can be seen from FIG. 2 that oil C is relatively difficult to hydrolyze compared to oils A and B.

FIG. 3 is a diagram showing the relationship between the moisture content and the deterioration of the ester oil.
As shown in FIG. 3, when the moisture content of the ester oil exceeds 350 ppm, the degree of degradation increases rapidly. Therefore, in the case of the ester oil of this test, the water management value can be set to 300 ppm, for example.

  As a result, the hydrolysis stability can be evaluated with a water concentration simulating an actual machine (for example, 1000 ppm or less), and therefore data consistent with the oil life of the actual machine can be obtained for different types of ester oils. In addition, a relative evaluation can be made as to whether the ester oil is easily deteriorated.

  Here, in the test method of ASTM D2619 according to the prior art, it is a hydrolysis reaction in the case of an excessive water amount in which a large amount of 25% water is added and water and oil are separated, so the actual machine was simulated. Unlike the evaluation of hydrolysis stability by moisture concentration (for example, 1000 ppm or less), it was impossible to acquire data consistent with the oil life of the actual machine.

That is, the ester oil used in an actual machine is rare when water is mixed so that water and oil are separated. Therefore, as in the present invention, by conducting a test with the water concentration in the ester oil kept constant under the same conditions as those used in a state where it is usually less than the saturated water concentration, It is possible to evaluate the decomposition stability side by side.
As a result, according to the present invention, a test method for correctly evaluating the hydrolysis stability of ester oil is provided.

DESCRIPTION OF SYMBOLS 10 Ester oil evaluation apparatus 11 Ester oil 12 Sealed container 13 Heating device 14 Trace moisture analyzer 15 Moisture 16 Trace moisture addition device 17 Moisture concentration control device

Claims (6)

A hermetically sealed container that holds a predetermined amount of ester oil hermetically sealed;
A heating device for hydrolyzing the ester oil by heating the ester oil in the sealed container;
A trace moisture analyzer for measuring trace moisture in the sealed container;
A trace moisture adding device for adding a trace amount of moisture into the sealed container;
An apparatus for evaluating an ester oil, comprising: a moisture concentration control device that maintains a moisture content of the ester oil in the sealed container at a predetermined concentration according to a measurement result of the trace moisture analyzer. In claim 1,
The ester oil evaluation apparatus is characterized in that hydrolysis is carried out when the water content at the predetermined concentration is equal to or less than the saturated water content of the ester oil. In claim 1 or 2,
The apparatus for evaluating ester oil, wherein the trace water addition device is a water supply device provided with a microsyringe. A predetermined amount of ester oil is kept sealed in a sealed container,
Measure the amount of trace moisture in the sealed container,
According to the measurement result of the trace amount of moisture, water is added to the ester oil in the sealed container,
Managing the amount of dissolved water in the ester oil to a predetermined concentration;
An ester oil evaluation method, wherein hydrolysis is performed while heating for a predetermined time. In claim 4,
The method for evaluating an ester oil, wherein the hydrolysis is carried out at a moisture content of the predetermined concentration below a saturated moisture content of the ester oil. In claim 4 or 5,
An ester oil evaluation method, wherein the total acid value of the ester oil is measured after the predetermined time has elapsed.

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