The function principle of diesel coagulant(2)

After adding coagulant in diesel fuel, when the temperature is lowered and the wax crystal is formed, the coagulant will play the role of nucleating agent and wax crystal together or adsorbed on the surface of the wax crystal, preventing the mutual bonding between the wax crystal, preventing the generation of a continuous crystalline network, making the wax crystal particles more fine and can pass through the filter well. This destruction or change of wax crystallization function of the coagulant can reduce the cold filtration point and freezing point of diesel fuel.

The addition of coagulant can change the crystalline form of wax or the size of wax crystals, but does not prevent the precipitation of wax crystals and reduce the amount of wax precipitation. Therefore, under the action of coagulant, when the temperature of diesel oil decreases to near the cold filtering point, there will be more fine wax crystal particles in diesel oil, which makes the oil cloudy in appearance, but this does not affect the smooth passage of diesel oil through the filter (or filter).

Light diesel oil is divided into different grades according to the freezing point, and each grade has corresponding freezing point and cold filtering point index. 0 light diesel oil means that the freezing point of this grade is not higher than 0℃, and its corresponding cold filtering point index is not higher than +4℃. Therefore, people often think that No. 0 diesel fuel indicates that it can be used normally at 0℃, which is actually a misunderstanding. 

To be precise, the No.0 diesel oil with the freezing point of 0℃ can only be used normally when the temperature is higher than its cold filtering point +4℃, and the diesel oil can not pass through the filter (or filter) when the cold filtering point and the temperature below; when the temperature drops to 0℃, the oil will lose its liquidity and show the solidified state.

The new national standard of light diesel oil, which will be implemented from January 1, 2002, has made a clear statement on the temperature of different grades of light diesel oil, and the minimum temperature of various grades of diesel oil suitable for use is the temperature above the cold filter point of the grade. In other words, different grades of light diesel fuel can be used normally only at the temperature above the cold filtering point.

The effect of the use of coagulant, not only depends on the performance of the coagulant itself, but also closely related to the composition of the added oil. A coagulant added to the composition of different diesel, the magnitude of reducing the cold filtration point (i.e. perceptibility) has a large difference.

So first of all, according to the perceptibility of various coagulants to the oil to choose the best coagulant. Second, according to the composition and nature of the oil added, after a small test in the laboratory to determine the best amount to add.