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This post was last edited by zjp on 2015-10-7 at 14:09. To increase the popularity of the chemical analysis section, a \"Question of the Day\" activity has been introduced; this aims to foster active technical exchanges while also providing members with certain financial rewards. 【Daily Question】 (Single-choice question) In the determination of the flash point of oils, which method should be used to measure the flash point of light oils? ( ) A. Open-cup method B. Closed-cup method C. Either method is acceptable. Please reply with your answer; participating in the quiz earns you +2 wealth points. Getting all answers correct adds another +3 to +8 wealth points. Those who provide thorough analysis and explanations for the questions or answers, or include detailed calculation processes, will receive additional wealth rewards. If your answer is correct and your analysis is accurate, it will be marked as the best reply (or the best assistance). Feel free to answer the questions. Note: We will close this post after 24 hours, and at that time we will announce the best reply (the best assistance), as well as the answer and explanation.
In the determination of the flash point of oils, which method should be used to measure the flash point of light oils? (B)
In the determination of the flash point of oils, which method should be used to measure the flash point of light oils? (B) A Open-cup method B Closed-cup method
In the determination of the flash point of oils, which method should be used to measure the flash point of light oils? ( ) B Closed-cup method
B Closed-cup method. . . . . . . . . . . . . . . .
This post was last edited by ylb913 on 2015-10-6 at 11:16: Method B, closed-cup method. The reason why the methods for determining petroleum products are divided into closed-cup and open-cup methods is mainly determined by the properties of the petroleum products and their conditions of use. Generally, closed-cup flash point testers are used for light petroleum products with a high evaporation rate, such as transformer oil, fuel oil, and solvent oils. Since the testing conditions are similar to those under which these light oils are actually stored and used, they can serve as a basis for fire safety control criteria. The open-cup flash point tester is mainly used for lubricants and heavy petroleum products. Because during the open-cup flash point test, the vapor formed when the petroleum product is heated spreads into the surrounding air, causing the measured flash point to be higher than actual. For most lubricants and heavy oils, especially when used in non-enclosed components or at low temperatures, even if there is a very small amount of light compounds present, they will evaporate during use and thus do not pose a risk of fire or explosion; therefore, these products are measured using an open flash point apparatus. In certain lubricant specifications, two quality criteria are specified: open and closed. Its purpose is to use the difference between the open and closed flash points to determine the breadth of the lubricant fraction and to check for the presence of light components mixed in. Some lubricants are used in sealed containers, and during use high temperatures can arise for various reasons (such as equipment overheating due to high speeds or other factors, resulting in circuit breaks or arcing). This can cause the lubricant to form decomposition products, or light components can be introduced from other parts. These lightweight components, after evaporating in a sealed container and mixing with air, pose a risk of explosion. However, when using the open-cup flash point test, the presence of such easily volatile light components may not be detected; therefore, it is specified that a closed-cup flash point tester should be used for the measurement. Oils that fall into this category include electrical oils, high-speed machine oils, and certain aviation lubricants. In light petroleum products as well, the open flash point method is used for measurement, such as solvent kerosene. This is entirely done to adapt to the operating conditions, so that the measured flash point is similar to the actual conditions during use.
B Closed-cup method. The closed-cup method is generally used for lightweight petroleum products with large square cross-sections, such as solvent oils and kerosene. Since the testing conditions are similar to those under which these lightweight oils are actually stored and used, it can serve as a basis for fire safety control criteria. The open cup method is commonly used for lubricants and heavy petroleum products.
In the determination of the flash point of oils, which method should be used to measure the flash point of light oils? (B) A Open-cup method B Closed-cup method C Either method is acceptable
The answer to this question is B: the closed-cup method
In the determination of the flash point of oils, which method should be used to measure the flash point of light oils? (B Closed-Cup Method)
In the determination of the flash point of oils, which method should be used to measure the flash point of light oils? (B) A. Open cup method; B. Closed cup method; C. Either method is acceptable. The closed cup flash point is used for light oils because it resembles the actual conditions under which such oils are stored and used, and can thus serve as a basis for safety and fire control measures