JP2017166853A - Method for evaluating deterioration phosphate eater oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of simply and accurately evaluating a degree of deterioration of phosphate eater oil.SOLUTION: A method for evaluating degree of deterioration of phosphate eater oil comprises: a process A of measuring the color tone of a sample and comparatively evaluate with the color tone of the new oil; a process B of dissolving the sample into hexane of a predetermined magnification; a process C of measuring membrane filter filtration time of sample hexane solution obtained in process B and comparatively evaluate with the filtration time of the new oil; and a process D of measuring an amount of filtration residue of the sample hexane solution obtained in process C and/or the color tone of the filtration residue, in which a degree of deterioration of the sample is evaluated from the filtration time of the sample in process C and the amount of the filtration residue and/or the color tone of the filtration residue in process D.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for evaluating deterioration of phosphate ester oil. More specifically, the present invention relates to a deterioration evaluation method capable of evaluating the deterioration degree of a phosphate ester oil that is a flame-retardant hydraulic oil by a simple method.

The rotational speed of the turbine at the power plant is controlled by an electronic hydraulic control (EHC). The hydraulic control device controls the control valve (governor valve) by pressurizing the control oil to a high pressure, but the temperature around the turbine is high and there is a risk of fire if hydraulic fluid leaks. Flame retardant phosphate ester is used for the control oil. This phosphate ester has a structure in which three hydrogen ions of phosphoric acid (H ₃ PO ₄ ) are replaced with phenyl groups. Although this phosphate ester does not burn, it is known that when heated, dehydration condensation forms a phosphoric acid condensate, and when water is added, it is hydrolyzed to produce polyphosphoric acid (Non-Patent Document 1). .

  Appropriate management of phosphate ester oil is important for maintaining the reliability of speed control, but phosphate ester is a sticky component (varnish) as a deteriorated product due to contamination with moisture, heat, air, metal components, etc. ), And the formed degradation product further promotes the degradation, and it is considered that the formation of hydrolysis and varnish aggregates is promoted. As the deterioration of the phosphoric ester oil progresses, adhesive components adhere to the narrow working parts of precision equipment, causing malfunction of the equipment. Generation of adhesive component (varnish) is such that metal and triphenyl phosphate react to produce metal phosphate salt, which gradually becomes large particles and can be visually observed as aggregates such as cloudiness and cloudiness. It is estimated that

  Fig. 1 is an estimation diagram of the mechanism by which triphenyl phosphate (EHC oil) reacts with water to hydrolyze to produce polyphosphoric acid and phenol, and reacts with metal to generate aggregates such as cloudiness and cloudiness. Indicates.

  Therefore, at present, line filters and activated clay filters are installed in the hydraulic system, and the filter is periodically replaced while removing acidic substances, moisture, impurities, etc., and the performance of phosphate ester oil is managed. . However, since the ability to remove moisture is low, it is in an environment where deterioration tends to proceed due to hydrolysis.

  The current management standard values include the amount of acidic substances (acid value), moisture content, viscosity, solids content (contamination), etc., and property management is conducted by periodic analysis, but within the management standard values However, there are many events that cause problems such as an increase in the differential pressure of the line filter, malfunction of the servo valve with a narrow sliding part, and fixation of the spool part.

  The cause of the increase in the differential pressure of the line filter is presumed to be due to the entry of foreign matter such as wear metal powder (Fe powder or the like) from the outside, or the adhesion of phosphate ester degradation products. The clearance of a narrow sliding part is generally less than 10 μm, and if a deteriorated phosphate ester adheres to and accumulates on the clearance part, a malfunction due to slow valve operation may be induced. While maintaining the performance of the phosphate ester and the amount of contaminants is important in maintaining it, the cause of sticking has not been clarified.

In view of the above-mentioned present situation, a purification device has also been studied in order to recover the performance of the phosphate ester (Non-Patent Document 2). However, no fundamental solution has been reached.
Furthermore, as a method for monitoring the deterioration state of the phosphate ester, the used oil is filtered, the oil is removed from the filter supplemented with the contaminants present in the oil before the filtration, and the filter is irradiated with light. There has also been proposed a method of monitoring the deterioration state of oil by projecting and detecting the color component of transmitted light in which the projected light is transmitted through a filter (Patent Document 1). However, this is not a simple method.

Japanese Patent No. 5190660

Toshihide Omori, Masuhiko Kawamura “Fundamental Study of Lubricating Oil Additives—Adsorption and Reaction of Phosphorus Extreme Pressure Additives on Iron Surfaces” Toyota Central R & D Review 28, 25 (1933) Takashi Suzuki, Jun Hishida, Hisato Yamagishi, Taiji Yoshimi “Evaluation of Introduction of EH Governor Oil (Phosphate Ester) Oil Purifier”, Proceedings of Thermal Nuclear Power Conference, Vol.10 (2014) P.1-6

  This invention is made | formed in view of the said problem, and makes it a subject to provide the method which can evaluate the deterioration degree of phosphate ester oil simply and correctly.

The present inventor has intensively studied to solve the above-mentioned problems, and phosphate esters can be visually checked for changes in color tone and viscosity due to deterioration due to use, but there is no correlation between color tone and moisture, and moisture content First, attention was paid to the occurrence of troubles such as clogging of control valves and filters even when the control value was within the reference value. And after estimating the deterioration mechanism of phosphate ester, the characteristic (color tone, adhesiveness) and deterioration thing of the deterioration component were analyzed, As a result, it reached this invention.
That is, the present invention is as follows.

(1) A method for evaluating the deterioration degree of phosphate ester oil,
Step A for measuring the color tone of the sample and evaluating the color tone of the new oil,
Step B for dissolving the sample in hexane at a predetermined magnification;
Measuring the membrane filter filtration time of the sample hexane solution obtained in step B, and comparing it with the filtration time of the new oil;
Step D for measuring the amount of filtration residue of the sample hexane solution obtained in Step C and / or the color tone of the filtration residue, and
A degradation evaluation method for phosphate ester oil, characterized in that the degradation degree of a sample is evaluated from the filtration time of the sample in Step C and the amount of filtration residue and / or the color tone of the filtration residue in Step D.

(2) further comprising a step E to confirm the decomposition or deterioration of the phosphoric acid ester oil, the step E includes any one or more of the steps of Step E ₁ to E ₃ below, the (1 ) Degradation evaluation method of phosphoric ester oil as described.
(E ₁ ) Step of confirming the production of polyphosphoric acid for the filtration residue of the sample hexane solution obtained in Step C (E ₂ ) Step of confirming metals and P for the filtration residue obtained in Step C (E ₃ ) The step of centrifuging the hexane solution prepared in step B and confirming the occurrence of adhesive components

  According to the present invention, the degree of deterioration due to the use of phosphate ester oil is evaluated, the color tone of the phosphate ester oil, the membrane filter filtration time, the amount and color tone of the filtration residue, and the adhesive component derived from the phosphate ester oil (varnish) ) Increase in comparison with the conventional evaluation method for controlling the acid value, moisture content, viscosity, etc. of phosphate ester oil or the method of exchanging the filter based on the increase in the differential pressure of the line filter. Accurate evaluation is possible.

  Moreover, deterioration of phosphate ester oil can be more accurately evaluated by confirming deterioration products and adhesive components (varnish) by infrared absorption spectrum, elemental analysis, or the like.

  Furthermore, the maintenance cost of the control oil can be reduced by providing a threshold for the filtration time of phosphate ester oil, the amount and color tone of the filtration residue, and accurately evaluating normal oil and deteriorated oil.

  The degradation evaluation method for phosphate ester oil according to the present invention is the quality of various phosphate ester oils used as control oil for turbines and the like of power plants in which the rotational speed is controlled by an electronic hydraulic system (EHC). Can be used for management.

An estimation diagram of the mechanism by which triphenyl phosphate (EHC oil) generates polyphosphoric acid and aggregates. The estimation figure of soot formation by the production | generation of the adhesion component (varnish) by hydrolysis of triphenyl phosphate (EHC oil), aggregation of an adhesion component (varnish), or low molecular weight. The state estimation figure of the adhesion component (varnish) and soot in a hexane solvent. Fourier transform infrared spectroscopy of membrane filter deposits and phosphate ester oil.

  In the degradation evaluation method according to the present invention, the phosphate ester oil to be evaluated is a control oil used for rotation speed control of a turbine or the like of a power plant or the like. Any of natural systems may be used.

In establishing the deterioration evaluation method of the present invention, the cause of the increase in the differential pressure of the line filter through which the phosphate ester oil passes is due to foreign matter such as metal wear powder from the outside, or the filter due to deterioration of the phosphate ester oil. The non-woven fabric was taken out from the line filter inlet and observed with an electron microscope.
In the observation with an electron microscope, no metal abrasion powder was found in the filter adhering substance. Therefore, the increase in the differential pressure of the line filter was not due to contamination from outside, but was derived from phosphate ester oil. There was found.
Moreover, when the infrared absorption spectrum of the surface was measured about the nonwoven fabric taken out from the line filter entrance part, the peak of the diphosphate was recognized.
From the above two preliminary examination results, it was found that triphenyl phosphate reacts with an external factor, the reaction product adheres to the filter, and increases the differential pressure of the line filter.

  In the degradation evaluation method for phosphate ester oil according to the present invention, based on the above preliminary examination results, the degradation estimation diagram of triphenyl phosphate (EHC oil) shown in FIG. 2 and the adhesive component in the hexane solvent shown in FIG. (Varnish) and soot state estimation map was devised.

  That is, triphenyl phosphate physically adsorbs to the metal that is the turbine material, reacts with moisture on the metal surface (in the air) to form phosphoric acid and phenol by hydrolysis, and the generated phosphoric acid undergoes dehydration condensation. To form polyphosphoric acid, triphenyl phosphate is heated to form a phosphoric acid condensate, and triphenyl phosphate reacts with metal to form a metal phosphate salt. Are known. However, details regarding the generation and separation of the adhesive component (hereinafter referred to as “varnish”) in the phosphoric ester oil are not known, and the substance is not specified.

  In the present invention, with the progress of hydrolysis of triphenyl phosphate, varnish elements (phosphoric acid and phenol) are generated, the varnish elements react with each other, and the varnish (polyphosphoric acid) is dispersed in the oil. As the varnish increased with time, it was presumed to be present as sticky varnish aggregates (phosphoric acid condensate, phosphoric acid metal salt) (see FIG. 2). And since the varnish agglomerate adheres to a membrane filter, it thought that it could isolate | separate by filtration operation.

  Further, when the varnish base or the varnish aggregate is further reduced in molecular weight over time to form a soot-like substance, and the triphenyl phosphate is reduced in molecular weight at a relatively high temperature, the soot-like substance (FIG. 2 and FIG. In FIG. 3, it was estimated that soot was formed. Here, the soot-like material means a black material and does not mean a carbon material. The soot-like material was considered to pass through the membrane filter because it was fine and non-sticky.

  Furthermore, since no precipitate is observed in the phosphate ester oil deteriorated to the extent that it needs to be replaced, the varnish and the soot-like substance are dispersed in the triphenyl phosphate in the deteriorated phosphate ester oil. I thought it was floating. Therefore, if hexane is selected as a solvent that is a good solvent (dissolves) for phosphate ester oils, a semi-good solvent (disperses) for varnishes, and a poor solvent (dissolves) for soot-like products, It becomes possible to separate the deteriorated phosphate ester oil.

That is, the deterioration evaluation method of the phosphate ester oil according to the present invention is
Step A for measuring the color tone of the sample and evaluating the color tone of the new oil,
Step B for dissolving the sample in hexane at a predetermined magnification;
Measuring the membrane filter filtration time of the sample hexane solution obtained in step B, and comparing it with the filtration time of the new oil;
And a step D for measuring the amount of filtration residue and / or the color tone of the filtration residue of the sample hexane solution obtained in the step C.
Then, the degree of deterioration of the sample is evaluated from the filtration time of the sample in Step C and the amount of filtration residue and / or the color tone of the filtration residue in Step D.

Although the evaluation method of the color tone in said process A and process D is not specifically limited, From the viewpoint of using a general apparatus, using a spectral color difference meter, the filtration residue on an oil or a membrane filter, A method of evaluating by L ^* a ^* b ^* values is preferred. According to the L ^* a ^* b ^* value, since the color tone of the deteriorated product can be evaluated by hue and saturation, the deterioration state can be evaluated more accurately than by visual evaluation.

  The evaluation of the color tone in the process A is preferably performed by comparing with the new phosphate ester oil to be evaluated. Thereby, the change degree of a color tone can be relatively evaluated with reference to new oil, and can be positioned as the first evaluation step by providing a predetermined threshold value. However, since the evaluation result of the color tone in the process A may not be related to the differential pressure filter of the filter, it is preferably positioned as an auxiliary evaluation process.

  In said process B, a sample (phosphate ester oil) is dissolved in hexane of predetermined magnification. The reason why the oil is dissolved in hexane is that the deteriorated oil has a tendency to thicken, and therefore, when the thickened oil is filtered, the filtration time becomes too long, thereby impairing the speed of evaluation. Hexane is optimal as a solvent for aggregating varnish components and precipitating soot. Hexane has a relatively high boiling point and does not significantly impair the reliability of evaluation due to volatilization during filtration.

  In the above step C, the membrane filter filtration time is measured for the sample hexane solution obtained in step B. In this case, it is preferable to set the standard of the filtration time to about 10 seconds to 2 minutes from the viewpoint of ensuring the quickness and reliability of the evaluation. The magnification of hexane with respect to the sample is preferably set so that the filtration time is within the above range.

  The membrane filter is preferably made of a material that does not dissolve or change quality when it is brought into contact with phosphoric ester oil and hexane. Examples thereof include a membrane filter made of PTFE (polytetrafluoroethylene). The filter pore diameter is not particularly limited, but is preferably 0.2 μm to 0.3 μm from the viewpoint that the varnish aggregate can be evaluated as a filtration residue.

The filtration rate should be evaluated in comparison with the new phosphate ester oil to be evaluated. Accordingly, the degree of varnish generation can be relatively evaluated based on the new oil, and can be positioned as one of the evaluation indexes for the degree of deterioration by providing a predetermined threshold value.
Moreover, when employ | adopting the color tone evaluation of the process A, it is preferable to evaluate a filtration rate about the phosphate ester oil evaluated as having a deterioration by color tone evaluation.

  In said process D, the quantity of the filtration residue of the sample hexane solution obtained in process C and / or the color tone of the filtration residue are measured. The amount of the filtration residue is measured by measuring the weight of the membrane filter to which the filtration residue adheres immediately after filtration. The amount of the filtration residue can be determined by [weight of membrane filter to which filtration residue adheres-weight of membrane filter (weight of air body)].

  The amount of the filtration residue and / or the color tone of the filtration residue may be evaluated by comparing with the new phosphate ester oil to be evaluated. Thereby, the production | generation degree of a varnish aggregate can be relatively evaluated on the basis of a new oil, and it can be positioned as one of the evaluation indexes of a deterioration degree by providing a predetermined threshold value.

Furthermore, in the deterioration evaluation method of the present invention, it is preferable to include a step E for confirming the decomposition or deterioration of the phosphate ester oil in addition to the steps A to D described above. The step E preferably has one or more steps of the following steps E _{1 to} E ₃ . That is, in the process E, one process selected from the above E _{1 to} E ₃ may be adopted, but two processes or three processes may be adopted.
(E ₁ ) Step of confirming the production of polyphosphoric acid for the filtration residue of the sample hexane solution obtained in Step C (E ₂ ) About the filtration residue obtained in Step C, a metal such as Fe, Mg, Ni, Cu, Zn (E ₃ ) Step of confirming generation of adhesive component by centrifuging the hexane solution prepared in step B

According to the above E ₁ step, by confirming the presence or absence of polyphosphate produced by hydrolysis of triphenyl phosphate, to obtain a confirmation of the substances produced by the degradation of phosphate ester oil, a proof of degradation Can do. Confirmation of the presence or absence of polyphosphate can be confirmed by an infrared absorption spectrum, and since a filtration residue is a trace amount, a Fourier transform infrared spectrum (FT-IR) or the like is preferably used.

According to the above E ₂ steps, metal powder or the like upcoming mixed externally Fe, phosphorous acid condensate, metal salt of phosphoric acid, by confirming the polyphosphoric acid or the like, generated by the degradation of phosphate ester oil Confirmation of substance and proof of deterioration can be obtained. Confirmation can be performed by elemental analysis or the like.

According to the above E ₃ steps, and visual confirmation of separation of the degradation products, by identifying separate depleted materials, can be obtained and confirmation of substances produced by the degradation of phosphate ester oil, a proof of degradation . Centrifugation may be performed by a known apparatus and method.

In the above step E, when employing any one step, E ₃ steps by can see the presence of soot-like material, soot-like material is presumed to occur in a state of advanced deterioration of the phosphoric acid ester oil than Rukoto, is good to adopt the E ₃ process. Also, in the case of employing one or two steps, and any one step of the E ₁ step or E ₂ step, it is good to adopt the E ₃ steps.

  In applying the degradation evaluation method of the present invention to individual samples, special temperature conditions and apparatus settings are not required, and a general-purpose apparatus may be used at room temperature. A measurement system related to phosphate ester oil or a substance substantially equivalent thereto may be constructed by adding ordinary technical considerations to those skilled in the art to the normal conditions and operation methods in each method. For details of these general technical means, it is possible to refer to reviews, books and the like known in the art.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited only to a following example.

Example 1
According to the following procedures and methods, the color tone, filtration speed, and filtration residue amount of the phosphate ester oil (component: triphenyl phosphate) as a sample were measured and evaluated.

a. Test Samples Samples 1 and 2 were obtained by collecting two deteriorated oils used in different turbines from the actual machine for the same phosphate ester oil used at different sites. These new oils were used as controls.

b. Color tone test (Process A)
For Sample 1 and Sample 2, the color tone of the stock solution was measured visually and with a spectral color difference meter SE6000 (manufactured by Nippon Denshoku Industries Co., Ltd.). Specifically, the side color by the spectral color difference meter was determined by brightness, hue, and saturation (L ^* a ^* b ^* method).
The results are shown in Table 1. The color tone was evaluated in comparison with the new oil.

  Although Sample 1 and Sample 2 were used for the same number of days, it was found from Table 1 that they were not the same in the visual and color difference meter evaluations.

On the other hand, in the L ^* a ^* b ^* value evaluation by the spectral color difference meter, the color tone was different between Samples 1 and 2 having the same number of days of use.

c. Filtration rate evaluation test (process B to process D)
5 ml each of sample 1 and sample 2 was dissolved in 5 ml of hexane. A commercially available PTFE filter (pore diameter 0.22 μm, 25 mmφ) was placed on a commercially available Buchner funnel. After 10 ml of the hexane solution was put into the funnel, it was immediately sucked with an aspirator, and the time until the hexane solution was completely sucked (filtering time) and the amount of filtration residue were measured. The measurement results are shown in Table 2.

  From Table 2, when the stock solution was filtered, the relative evaluation of the filtration time of the new oil and the deteriorated oil (Sample 1, Sample 2) was similar to the relative evaluation obtained in Example 1, Since the difference in time ratio was small, the reliability was lacking, and since the filtration time of the new oil was more than 10 minutes, the rapidity was lacking. By using a hexane solution, the difference in the filtration time ratio is increased, so that reliability is improved, an appropriate filtration time can be obtained, and errors due to volatilization of hexane during filtration are minimized. I was able to.

  Regarding the amount of filtration residue, sample 1 was larger than fresh oil and sample 2, and was consistent with the results of the color tone evaluation (step A).

  The color tone of the filtration residue had a light brown color that was supposed to depend on the deteriorated product by visual inspection, but the color difference was clearly large in the spectrocolorimeter.

d. Identification of Filtration Residue With respect to the filtration residue, the measurement results of Sample 1 and Sample 2 by Fourier transform infrared spectroscopy (FT-IR) are shown in comparison with FIG. In sample 1, a characteristic peak of diphosphate was observed at 1,400 to 800 cm ⁻¹ , but not in sample 2.
As a result of elemental analysis of the filtration residue, Sample 1 showed the presence of metals such as Fe, Mg, Al, Ca, Cu, and Zn, and P, but Sample 2 did not.

e. Confirmation of varnish generation by centrifugation of hexane solution Test sample 1, sample 2 and hexane solution of fresh oil, 10 ml each were transferred to a centrifuge tube with a capacity of 50 ml, and then centrifuged at 2,500 rpm for 10 minutes. went.
As a result, the new oil showed no foreign matter in the sample after centrifugation. In sample 1, black soot was observed at the bottom of the centrifuge tube. In Sample 2, a foreign material that had been sprinkled was also observed in the sample after centrifugation, but no black soot was observed.
The black soot-like material generated in Sample 1 was taken out and analyzed by Fourier transform infrared spectroscopy (FT-IR). As a result, no organic matter was detected, so it is considered that the polyphosphate was further decomposed.

  Table 3 summarizes the evaluation results of Sample 1, Sample 2, and new oil in Step A to Step E. From Table 3, the degree of deterioration of phosphate ester oil has no correlation with the number of days passed (the number of days in use), and in Sample 1, the deterioration was promoted by mixing water or metal into the control oil for some reason. It is guessed. Moreover, it turns out that management maintenance of control oil is possible by setting a threshold value to the filtration time ratio and the filtration residue amount.

  From the above results, it is difficult to make the deterioration of the color tone of phosphate ester oil as an absolute evaluation index, but it is adopted as an auxiliary evaluation index.In addition, the amount of varnish and varnish agglomerates can be calculated according to the filtration time and filtration residue. It was found that the degradation degree of the phosphate ester oil can be evaluated by a quick and simple operation by evaluating the amount or the color tone. Therefore, by evaluating the degree of deterioration of the control oil for each turbine, it is possible to realize optimization of the use period and cost reduction.

The present invention provides a simple and inexpensive method for evaluating deterioration of control oil, and is useful for high-precision evaluation and diagnosis, which is a problem in the evaluation of control oil currently used in turbines in power plants. is there.

Claims (2)

A method for evaluating the deterioration degree of phosphate ester oil,
Step A for measuring the color tone of the sample and evaluating the color tone of the new oil,
Step B for dissolving the sample in hexane at a predetermined magnification;
Measuring the membrane filter filtration time of the sample hexane solution obtained in step B, and comparing it with the filtration time of the new oil;
Step D for measuring the amount of filtration residue of the sample hexane solution obtained in Step C and / or the color tone of the filtration residue, and
A degradation evaluation method for phosphate ester oil, characterized in that the degradation degree of a sample is evaluated from the filtration time of the sample in Step C and the amount of filtration residue and / or the color tone of the filtration residue in Step D. Further comprising a step E to confirm the decomposition or deterioration of the phosphoric acid ester oil, the step E includes any one or more of the steps of Step E ₁ to E ₃ below, phosphorus claim 1, wherein Degradation evaluation method of acid ester oil.
(E ₁ ) Step of confirming the production of polyphosphoric acid for the filtration residue of the sample hexane solution obtained in Step C (E ₂ ) Step of confirming metals and P for the filtration residue obtained in Step C (E ₃ ) The step of centrifuging the hexane solution prepared in step B and confirming the occurrence of adhesive components

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