Are flash point, ignition point, and ignition temperature the same thing? How to tell the difference?

I) Flash point: It refers to the lowest temperature, expressed in °C, at which, under specified heating conditions and with the flame passing over the mixture of vapors emitted by the oil and air at regular intervals, ignition of the oil surface occurs. The flash point of a fuel indicates its flammability, the content of volatile compounds, the degree of vaporization, and its safety level. The hazard classification of fuels is also determined based on their flash point. Oils with a flash point below 61°C are flammable, while those with a flash point above 61°C are combustible. It is prohibited to heat the oil to its flash point during storage, transportation, and use; the maximum heating temperature should generally be 20–30°C below the flash point. There are two methods for determining the flash point of oils: the closed-cup method and the open-cup method. The main difference between the two is that in a closed-cup flash point apparatus, the oil vapor is heated inside a sealed container, whereas in an open-cup flash point apparatus, the oil vapor can freely disperse into the surrounding air. As a result, the flash point values obtained using these two instruments for the same oil are different; the higher the flash point of the oil, the greater the difference between the two values. The closed-cup method is used to determine the flash point of fuels and light oils, while the open-cup method is used to determine the flash point of heavy oils. 　　(II) Ignition point: Also known as the flash point, it refers to the lowest temperature at which, under specified heating conditions and when the oil is brought close to a flame, it not only flashes but also continues to burn for more than 5 seconds. The ignition point is generally 0–20°C higher than the flash point. 　　(III) Autoignition point: The lowest temperature at which, after heating the oil to a very high temperature and exposing it to air, the oil ignites on its own due to intense oxidation under different ignition conditions is known as the autoignition point. The main difference between the autoignition point and the flash point and ignition point is that no ignition source is required for the former, whereas the latter requires an external fire source to be ignited. The auto-ignition points of all petroleum products are much higher than room temperature; however, when hot oil leaks from connections in pipelines, flanges, etc. and comes into contact with air, it can often cause a fire on its own. Among various types of oils, the lighter the oil, the lower its flash point and ignition point, while its auto-ignition point is higher.

What is the concept of ignition temperature? Thank you!

Ignition temperature: The ignition temperature refers to the lowest temperature of the wall of the reaction container at normal temperature and pressure, at which heating a mixture of flammable gas and air inside the container causes it to catch fire. It can be used as a scale for assessing the combustion of flammable gases and liquids within a heating element. Based on the ignition mechanism, it can be seen that the ignition temperature is a non-physical constant, which is influenced by various factors such as the concentration of the combustible material, pressure, the reaction vessel, and additives.

It is important to distinguish these concepts clearly; the flash point is crucial for safe production

The ignition temperature and the auto-ignition temperature should be the same, right?

Flash point: It refers to the lowest temperature, expressed in °C, at which, under specified heating conditions and with the flame passed over the mixture of vapors emitted by the oil and air at regular intervals, ignition of the oil surface occurs. Ignition point: Also known as the flash ignition point, it is the lowest temperature at which, under specified heating conditions and when the oil is brought close to a flame, not only does ignition occur but the oil also continues to burn for more than 5 seconds. The ignition temperature is essentially the temperature at which combustion occurs, that is, the flash point

The flash point is the temperature at which vapor burns, while the ignition point is the temperature at which a liquid burns.

The flash point is the lowest temperature at which a flammable liquid or solid can release enough vapor to form a flammable mixture with air at the surface of the liquid or solid within its container. Ignition point: It refers to the lowest temperature at which, under specified heating conditions, when brought near a flame, not only does flashing occur but the material can also continue to burn for more than 5 seconds. The ignition point is generally 0–20°C higher than the flash point.