Difference Between 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 oil and water emulsion to separate out in distinct layers.

Aniline point and the steam emulsion number are properties of lubricant oils. There are many differences between these two terms. In this article, we are discussing the features of aniline point and steam emulsion number, and the difference between aniline point and steam emulsion number.

1. Overview and Key Difference
2. What is Aniline Point
3. What is Steam Emulsion Number
4. Side by Side Comparison – Aniline Point vs Steam Emulsion Number in Tabular Form
5. Summary

What is 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, lower the aniline point, higher the aromatic compound content in the lubricant oil.

Moreover, 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.

What is 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. Some oils form emulsions with water easily.

Difference Between Aniline Point and Steam Emulsion Number

Figure 01: Formation of an Emulsion

The tendency of a lubricant oil-water emulsion to break can be determined by a specific method. This involves taking a small amount of the oil into a test tube, steaming the oil until it bubbles, followed by placing the tube in a temperature bath while the time is recorded in terms of seconds. When the water separates from the oil, showing us two distinct layers, the time in seconds is taken as the steam emulsion number. A good lubricant oil should have a low steam emulsion number.

What is the Difference Between 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. Moreover, aniline point is a measurement of temperature while steam emulsion number is a measurement of time.

Below is a summary of the differences between aniline point and steam emulsion number in tabular form.

Summary – Aniline Point vs Steam Emulsion Number

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