JP6152366B2 - Compressor oil - Google Patents

Description

  The present invention relates to a compressor oil used for lubrication of a gas compressor that compresses a gas.

  For high-efficiency operation with a compressor (gas compressor), it is effective to prevent leakage of compressed gas. Therefore, compressor oil for preventing gas leakage is used in the compressor. In addition to preventing gas leakage, the compressor oil is also required to maintain lubricity of the bearing portion and the like. As compressor oil, what mixed various additives with base oil, such as mineral oil, is known (for example, refer to patent documents 1-3).

Japanese Patent Laid-Open No. 2005-239897 JP 2008-179679 A JP-A-11-335684

  By the way, for example, in the case of a compressor for compressing hydrogen for a fuel cell, it is important to suppress contamination by a specific element in order to compress very high purity hydrogen. However, when the above conventional compressor oil is used, there is a possibility that specific components contained in the base oil and additives in the compressor oil contaminate the compressed gas.

  In particular, a compressor that compresses hydrogen easily wears due to hydrogen embrittlement and the like, and the compressor oil used in such a compressor requires high lubricity. However, conventional compressor oils are not always sufficient in terms of lubricity, and there is still room for improvement as they can be put into practical use.

  Then, this invention is made | formed in view of said subject, and it aims at providing the compressor oil which can fully prevent the contamination of the gas to compress and has high lubricity.

  In order to solve the above problems, the present invention is based on a total amount of compressor oil, 90 to 99.995% by mass of hydrocarbon oil having a sulfur content of 0.1% by mass or less and an aromatic content of 1% by mass or less. An oil-based additive composed of an oxygen-containing organic compound is contained in an amount of 0.005 to 10% by mass, and a compressor oil having a sulfur content of 0.1% by mass or less is provided.

  The oxygen-containing organic compound contained in the compressor oil of the present invention is preferably a fatty acid having 14 to 22 carbon atoms, and more preferably a branched fatty acid having 14 to 22 carbon atoms.

  The compressor oil according to the present invention is preferably used in a compressor that compresses hydrogen.

  According to the compressor oil of the present invention, contamination of the gas to be compressed can be sufficiently prevented, and high lubricity can be achieved.

It is a ¹³ C-NMR chart of isostearic acid A used in the example. It is a ¹³ C-NMR chart of isostearic acid B used in the example.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The compressor oil according to the embodiment of the present invention is 90 to 99.995% by mass of hydrocarbon oil having a sulfur content of 0.1% by mass or less and an aromatic content of 1% by mass or less, based on the total amount of the compressor oil. 0.005 to 10% by mass of an oil-based additive composed of an oxygen-containing organic compound. Moreover, the sulfur content of the compressor oil which concerns on this embodiment is 0.1 mass% or less on the basis of compressor oil whole quantity.

[Hydrocarbon oil]
The sulfur content of the hydrocarbon oil is 0.1 mass% (1000 mass ppm) or less, preferably 10 mass ppm or less, more preferably, based on the total amount of the hydrocarbon oil, from the viewpoint of sufficiently preventing contamination of the compressed gas. Is 1 ppm by mass or less. The sulfur content in the present invention means a value measured according to JIS K2541 “Crude oil and petroleum products—sulfur content test method”.

  The aromatic content of the hydrocarbon oil is 0.1% by mass or less, preferably 0.01% by mass or less, based on the total amount of the hydrocarbon oil, from the viewpoint of sufficiently preventing contamination of the compressed gas. . The aromatic content referred to in the present invention means a value measured according to the fluorescent indicator adsorption method of JIS K2536 “Petroleum products-component test method”.

  The hydrocarbon oil in the present embodiment is not particularly limited as long as the sulfur content and aromatic content satisfy the above conditions. For example, mineral oil base oil, wax decomposition base oil, synthetic base oil, or these Two or more kinds of mixed oils can be mentioned. Furthermore, examples of preferred synthetic base oils include poly α-olefins or hydrides thereof. Waxes such as olefin oligomers, slack waxes, FT waxes and the like, isomerized base oils, those containing aromatic and / or unsaturated compounds, such as hydrogenated fractions obtained by distilling terpene oil or crude oil It is done.

  Moreover, it is preferable that the hydrocarbon oil in this embodiment has the following properties.

The kinematic viscosity of the hydrocarbon oil is not particularly limited, but the kinematic viscosity of the hydrocarbon oil at 40 ° C. is preferably 10 to 800 mm ² / s, 15 to 500 mm ² / s, more preferably 20 to 300 mm ² / s, 30. It is -200 mm < ² > / s, More preferably, it is 50-90 mm < ² > / s. The kinematic viscosity at 100 ° C. of hydrocarbon oil, preferably ^{2~60mm 2 / s, 3~50mm 2 /} s, more preferably ^{4~35mm 2 / s, 5~25mm 2 /} s, more preferably 8 ˜15 mm ² / s. When the kinematic viscosity of the hydrocarbon oil is within this range, wear at the sliding portion can be reduced and the stirring resistance can be lowered, so that energy consumption can be suppressed.

  The viscosity index of the hydrocarbon oil is preferably 120 to 160, more preferably 130 to 155.

  The kinematic viscosity and viscosity index at 40 ° C. and 100 ° C. in the present invention mean values measured according to JIS K2283 “Crude oil and petroleum products—Kinematic viscosity test method and viscosity index calculation method”, respectively.

  In order to prevent light hydrocarbons from being mixed into the compressed gas, the distillation range of the hydrocarbon oil is used as an initial boiling point of the gas chromatography distillation test specified in JIS K2254 “Petroleum products-distillation test method”. It is preferably 250 ° C. or higher, and more preferably 300 ° C. or higher. Moreover, it is preferable that it is 350 degreeC or more as a 1% distillation point, and 400 degreeC or more is the most preferable. It is also preferable to reduce a trace amount of light hydrocarbons that are not detected as initial boiling points in the gas chromatography distillation test. Therefore, when manufacturing hydrocarbon oil, it is preferable to pass through the distillation process accompanied by careful flushing, for example.

  The hydrocarbon oil content is 90 to 99.995 mass%, preferably 95 to 99.99 mass%, more preferably 98 to 99.9 mass%, based on the total amount of the compressor oil.

[Oil additive]
The compressor oil according to this embodiment contains an oily additive made of an oxygen-containing organic compound. Examples of such oxygen-containing organic compounds include monovalent carboxylic acids represented by fatty acids, polyvalent carboxylic acids, monohydric alcohols, polyhydric alcohols, esters, and partial ester compounds of polyhydric alcohols. Among these, fatty acid, polyhydric alcohol, and partial ester compounds of polyhydric alcohol are preferred because of their high adsorption ability and low corrosivity.

As the fatty acid, a fatty acid having 14 to 22 carbon atoms is preferable, and a branched fatty acid having 14 to 22 carbon atoms is more preferable. It is particularly preferable that the fatty acid has 16 to 20 carbon atoms. Saturated fatty acids are also preferred. Examples of fatty acids include oleic acid, isostearic acid, lauric acid, and stearic acid. Of these, isostearic acid is most preferred. Among the branched fatty acids, in ¹³ C-NMR analysis (broadband complete decoupling), the integrated value (peak area) of the peak intensity in the region where the chemical shift is 40 ppm or more is the sum of the integrated values (peak area) of the peak intensity of all carbons. On the other hand, it is preferably 15% or less, more preferably 10% or less, still more preferably 1% or less, particularly preferably 0.5% or less. The reason why such a fatty acid is preferable is that the region having a chemical shift of 40 ppm or more is caused by a methine group and carbon adjacent to the methine group. ing.

  The ratio of the fatty acid in the oxygen-containing organic compound is preferably 60 to 100% by mass, more preferably 85 to 100% by mass, and still more preferably 95 to 100% by mass, based on the total amount of the oxygen-containing organic compound. .

  The content of the oil-based additive contained in the compressor is 0.005 to 10% by mass, preferably 0.01 to 5% by mass, more preferably 0.1 to 2% by mass, based on the total amount of the compressor oil. %, And more preferably 0.2 to 1% by mass.

[Compressor oil]
The sulfur content of the compressor oil is 0.1% by mass (1000 ppm by mass) or less, preferably 10 ppm by mass or less, and more preferably 1 ppm by mass or less. The sulfur content in the present invention is measured by an ultraviolet fluorescence method defined in JIS K2541-6 “Sulfur content test method”.

  The metal element content of the compressor oil is preferably 100 mass ppm or less, more preferably 10 mass ppm or less, from the viewpoint of sufficiently preventing contamination of the gas to be compressed. The metal element content in the present invention can be measured, for example, by inductively coupled plasma (ICP) emission spectroscopy, and the sample pretreatment is a solvent dilution method defined in JPI-5S-38-92. Etc. can be used.

  The compressor oil may be composed of the above base oil and an oily additive composed of an oxygen-containing organic compound, but may further contain other base oils and additives as necessary.

  For example, the compressor oil according to the present embodiment can further contain an antifoaming agent. Examples of the antifoaming agent include acrylate antifoaming agents such as polyacrylate and siloxane antifoaming agents such as alkylpolysiloxane. The content of the antifoaming agent is preferably 100 mass ppm or less based on the total amount of the compressor oil.

  The compressor oil which concerns on this embodiment can be manufactured by mixing said component. Here, in the compressor oil preparation step, it is preferable to remove light hydrocarbons from the viewpoint of preventing light hydrocarbons from being mixed into the gas compressed when the compressor oil is used. The removal of light hydrocarbons can be performed, for example, by mixing components such as base oil and oily additive, and then stirring the mixture at a temperature of, for example, 80 ° C. or more for 3 hours or more. Or it is preferable to perform bubbling with nitrogen or dry air, and it is more preferable to perform nitrogen bubbling for 3 hours or more at the temperature of 80 degreeC or more.

  The light hydrocarbon content in the compressor oil is preferably 100 mass ppm or less, more preferably 50 mass ppm or less, and most preferably 25 mass ppm or less, based on the total amount of the compressor oil. The light hydrocarbon content in the compressor oil in the present invention is calculated from the peak intensity derived from hydrocarbons having 10 or less carbon atoms by gas chromatography analysis defined in JIS K2254 “Petroleum products-distillation test method”. The

[Compressor]
The structure of the compressor using the compressor oil according to the present embodiment is not particularly limited, but a preferable compressor is a positive displacement compressor (or a rotary gas compressor).

  The gas to be compressed in the compressor using the compressor oil according to the present embodiment is not particularly limited, but hydrogen gas is preferable, high purity hydrogen gas of 99.9% or more is more preferable, and 99.97%. The above high purity hydrogen gas is particularly suitable.

  Although it does not restrict | limit especially as a pressure of the gas compressed in the compressor using the compressor oil which concerns on this embodiment, 0.5 MPa or more is suitable, 5 MPa or more is more suitable, 35 MPa or more, Furthermore, 70 MPa or more is preferable. Particularly preferred. The upper limit is preferably 200 MPa or less.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to a following example.

[Sample oils 1-7]
In test oils 1 to 7, compressor oils shown in Table 1 were prepared using the hydrocarbon oil, oily additive, and antifoaming agent shown below. Table 1 shows the blending conditions (stirring temperature and time) for each sample oil.
(Hydrocarbon oil)
PAO: Decene derivative, poly α-olefin (oil additive) having a kinematic viscosity at 40 ° C. of 63 mm ² / s, a kinematic viscosity at 100 ° C. of 9.6 mm ² / s, and a viscosity index of 134
Isostearic acid A: Nissan Chemical Industries, Ltd. Product isostearic acid B: Croda Japan Co., Ltd. Prisorine 3503
(Defoamer)
Siloxane-based antifoaming agent: dimethylpolysiloxane having a kinematic viscosity at 25 ° C. of 3000 mm ² / s

For isostearic acid A and isostearic acid B, ¹³ C-NMR was measured by the following method.
Device name: Varian-NMR system 500, resonance frequency: 125.76 MHz, solvent: deuterated chloroform, measurement temperature: room temperature (25 ° C.), repetition time: 2 sec, integration number: 1024 times, probe: diameter 5 mm
(The measurement method used broadband complete decoupling.)

A ¹³ C-NMR chart of isostearic acid A is shown in FIG. 1, and a ¹³ C-NMR chart of isostearic acid B is shown in FIG. The ratio of the integrated value (peak area) of the peak intensity showing a chemical shift of 40 ppm or more to the total integrated value (peak area) of the peak intensity of all carbon is 16.8% for isostearic acid A and 0.8% for stearic acid B. 1%.

  Next, as shown below, compressor oils of test oils 1 to 7 were subjected to evaluation of a friction coefficient, evaluation of a hydrocarbon content of 10 or less carbon atoms, a foaming test, and a shell four-ball test. The results are shown in Table 1.

(Evaluation of friction coefficient)
Evaluation of the friction coefficient was performed in accordance with the method prescribed in the “Report of Noritsumi Hamada Aviation Research Institute Report (No. 279, 1943)”.

(Evaluation of hydrocarbon content with 10 or less carbon atoms)
The content of hydrocarbons having 10 or less carbon atoms was calculated from the peak intensity derived from hydrocarbons having 10 or less carbon atoms by gas chromatography analysis defined in JIS K2254 “Petroleum products-distillation test method”. .

(Bubbling test)
The test was carried out in the sequence I (test temperature: 24 ° C.) defined in JIS K2518 “Petroleum product-lubricating oil-foaming test method”.

(Shell 4-ball test)
Based on ASTM D4172, it evaluated by measuring the wear scar diameter of the steel ball in room temperature (oil temperature) at the rotation speed of 1200 rpm, the load of 30 kgf, and the test time of 1 hr.

Claims (2)

Based on the total amount of compressor oil,
90 to 99.995% by mass of a hydrocarbon oil having a sulfur content of 0.1% by mass or less and an aromatic content of 1% by mass or less;
Containing 0.005 to 10% by mass of an oil-based additive composed of an oxygen-containing organic compound,
Sulfur content Ri der 0.1 wt%, light hydrocarbons content consisting of hydrocarbon 10 carbon atoms is not more than 100 mass ppm, a compressor oil,
In the ¹³ C-NMR analysis (broadband complete decoupling), the oxygen-containing organic compound has an integrated value (peak area) of peak intensity in a region where the chemical shift is 40 ppm or more and an integrated value (peak area) of peak intensity of all carbons. A compressor oil containing a branched fatty acid having 14 to 22 carbon atoms, which is 1% or less of the total . Used in a compressor for compressing the hydrogen compressor oil according to claim 1.

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