The influence of water soluble acids and bases in hydraulic oil on purification equipment of oil filter
2018/5/15 Viewers:
Water soluble acids and bases in oils refer to mineral acids and bases that can be dissolved in water. Mineral acids are mainly sulfuric acid and its derivatives, including sulfonic acids and acid esters; and low molecular organic acids (HCOOH, CH3COOH, C2H3COOH, etc.). Water soluble bases are mainly caustic sodium or sodium carbonate. The sources of water soluble acids and bases in oil products are: (1) in the process of refining and regeneration, oil remains in oil due to incomplete cleaning and neutralization. (2) during the storage, transportation and use of oil products, pollution and oil oxidation occur. In general, new oil or reclaimed oil should be treated properly, and water soluble acid thieves should not be found in oil products. However, in the process of use of oil, the oil will oxidize to produce a series of oxidation products due to the long-term contact with oxygen in the air and a certain temperature, among which there are low molecular organic acids.
The following methods are used to determine water soluble acids and bases in oil.
(1) water soluble acid and alkali qualitative determination (colorimetric method), that is, GB259 method. This method is in the same volume neutral distilled water from the test oil, and drops human methyl orange and phenolphthalein indicator respectively, judging the existence of water soluble acid and alkali from the change of the color of the extracted liquid. The water soluble acids and bases found in the experiment do not need to identify which kind of acids and bases are they belong to, but only generally judge the chemical reaction of water soluble acids and bases. So this qualitative reaction is also known as the "reaction" test. This method is mostly used for the identification of the new oil from the factory. The purpose is to check whether there are any residual inorganic acids and bases in the processing of oil.
(2) the determination of water soluble acid (colorimetric method), that is, the method of GB7598--87 determination. The method is to shake the mixture of distilled water and test oil with equal volume, take its water extraction liquid and add an indicator (such as the new oil with brominated cresol violet as indicator, such as the brominated cresol green as an indicator in the test operation), and the colorimetric determination in the colorimetric tube with the standard color grade. The determined result is expressed in the pH value. This method is mostly used in the power system. Because in operation transformer (GB7595-87), the water-soluble acid (pH value) is greater than or equal to 4.2. Therefore, the bromocresol green with pH value of 3.8~5.4 is used as an indicator and the standard color level of pH value of 0.2 is set. For new oil, water soluble acids and bases are not required (see national standard for transformer oil GB2536-90). If there is no water soluble acid and alkali in the water extract, then the pH value of the water extract should be 7, that is, neutral. Therefore, the bromocresol violet or bromothyme blue, which has a range of 5.2~6.8 discoloration, or 6.0~7.6, should be used as an indicator for the determination of new oil soluble Yin alkali.
(3) water soluble acid method (acidity meter method), namely DL429.3? -91 method. The principle of this method is to measure the activity of H in water solution by conductance, and to use a simple acidity meter to determine the pH value of the extraction liquid, and the preparation of the standard color level can be saved. However, it should be noted that the pH value measured by acidity meter is about 0.2 higher than that of visual colorimetry (2).
The following methods are used to determine water soluble acids and bases in oil.
(1) water soluble acid and alkali qualitative determination (colorimetric method), that is, GB259 method. This method is in the same volume neutral distilled water from the test oil, and drops human methyl orange and phenolphthalein indicator respectively, judging the existence of water soluble acid and alkali from the change of the color of the extracted liquid. The water soluble acids and bases found in the experiment do not need to identify which kind of acids and bases are they belong to, but only generally judge the chemical reaction of water soluble acids and bases. So this qualitative reaction is also known as the "reaction" test. This method is mostly used for the identification of the new oil from the factory. The purpose is to check whether there are any residual inorganic acids and bases in the processing of oil.
(2) the determination of water soluble acid (colorimetric method), that is, the method of GB7598--87 determination. The method is to shake the mixture of distilled water and test oil with equal volume, take its water extraction liquid and add an indicator (such as the new oil with brominated cresol violet as indicator, such as the brominated cresol green as an indicator in the test operation), and the colorimetric determination in the colorimetric tube with the standard color grade. The determined result is expressed in the pH value. This method is mostly used in the power system. Because in operation transformer (GB7595-87), the water-soluble acid (pH value) is greater than or equal to 4.2. Therefore, the bromocresol green with pH value of 3.8~5.4 is used as an indicator and the standard color level of pH value of 0.2 is set. For new oil, water soluble acids and bases are not required (see national standard for transformer oil GB2536-90). If there is no water soluble acid and alkali in the water extract, then the pH value of the water extract should be 7, that is, neutral. Therefore, the bromocresol violet or bromothyme blue, which has a range of 5.2~6.8 discoloration, or 6.0~7.6, should be used as an indicator for the determination of new oil soluble Yin alkali.
(3) water soluble acid method (acidity meter method), namely DL429.3? -91 method. The principle of this method is to measure the activity of H in water solution by conductance, and to use a simple acidity meter to determine the pH value of the extraction liquid, and the preparation of the standard color level can be saved. However, it should be noted that the pH value measured by acidity meter is about 0.2 higher than that of visual colorimetry (2).
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