The key difference between aniline point and steam emulsion number is that aniline point is the minimum temperature at which equal volumes of aniline and lubricant oil are miscible with each other whereas steam emulsion number is the time it takes for an oil and water emulsion to separate out in distinct layers.
Aniline point
Aniline point is a measure of the aromaticity of an oil. It is the point at which the oil becomes miscible in aniline. Thus the lower the aniline point, the higher the aromatic content. A high aniline point indicates that the fuel is highly paraffinic and hence a high Diesel Index and a very good ignition quality. Aniline being an aromatic compound freely mixes with aromatics so a low aniline point indicates a low diesel index (because of a high percentage of aromatics).
Determination of aniline point
Equal volumes of aniline and oil are stirred continuously in a test tube and heated until the two merge into a homogeneous solution. The heating is stopped and the tube is allowed to cool. The temperature at which the two phases separate out is recorded as an aniline point.
Aniline point is the minimum temperature at which equal volumes of aniline and lubricant oil are miscible with each other. The aniline point is given for lubricant oils. This value gives an approximation for the content of aromatic compounds in the oil because the miscibility of aniline shows the presence of aromatic compounds in the oil, similar to aniline (because aniline is also an aromatic compound). Therefore, the lower the aniline point, the higher the aromatic compound content in the lubricant oil.
Moreover, the aniline point is important as a reasonable proxy for the aromaticity of lubricant oils that mainly contains saturated hydrocarbon compounds such as alkanes and paraffin, or unsaturated compounds such as aromatic compounds. However, the chemical functionalization of the oil such as chlorination, sulfonation, etc. can interfere with the measurement of the aniline point because it can change the solvency of the oil.
We can determine the aniline point by continuously stirring equal volumes of aniline and the oil in a test tube, followed by the heating of the mixture until the two components merge into a homogeneous solution. The heat treatment is then stopped to allow the test tube to cool down. Here, the temperature at which the two phases separate out can be recorded as the aniline point.
The aniline point (AP) is an important physical property of a petroleum fraction. The AP gives an indication of the aromatic hydrocarbon content in a hydrocarbon mixture and can also be an indicator of the ignition point of a diesel fraction. Aniline point is a measure of the aromaticity of an oil. It is the point at which the oil becomes miscible in aniline. Thus the lower the aniline point, the higher the aromatic content.
Steam Emulsion Number
The steam emulsion number is the time it takes for oil and water emulsion to separate out in distinct layers. We can measure this value under the emulsification of lubricant oil. This is a property of oils that gives them the ability to intimately mix with water, forming a mixture known as an emulsion.
Steam emulsification number is the time (in seconds ) required for an emulsion of lubricating oil and water to separate into distinct layers at 900C.
Emulsification is the proper of oil to get mixed with water forming a dispersed phase of oil in water or water in oil, the emulsification property of oils is expressed in terms of stream emulsification number and is determined by A.S.T.M ( American society for testing material) method.
Determination of steam emulsification number
Steam of 1000C is bubbled through 20mL of lubricating oil till its temperature reaches 90 steams 0C When the oil temperature reaches 900C. The time required (in seconds) for water (formed due to condensation of steam) and oil to separate into two distinct layers is noted as steam emulsification number.
The significance of steam emulsification number
Good lubricating oil has a low steam emulsification number; so that when it comes in contact with water it does not form an emulsion.
The emulsion has a tendency to collect dirt, dust, etc which reduces the lubricating property emulsification number arrears vegetable oils have high stream emulsification number whereas vegetable oils have high steam emulsification number.
Oil having high steam emulsification number is preferred for the preparation of lubrication emulsification like cutting fluids.
There are many differences between the terms aniline point and steam emulsion number. The key difference between aniline point and steam emulsion number is that aniline point is the minimum temperature at which equal volumes of aniline and lubricant oil are miscible with each other whereas steam emulsion number is the time it takes for an oil and water emulsion to separate out in distinct layers.