About the ash content

Ash content

Ash is an inorganic residue obtained by calcining a residue after carbonization of a sample under specified conditions, expressed as a mass percentage.

The ash side determination method is carried out according to GB/T508 (YT-508 ash analyzer). When measuring, the ashless filter paper is used as the ignition core to burn the test oil, and then the solid residue is repeatedly forged at a temperature of (755 ± 25) °C. After burning, after cooling, weigh to constant weight. It is then calculated as a mass percentage.

The ash in petroleum products contains CaO, MgO, Fe2O3, siO2, V2O5 and Na2O. These oxides are formed by decomposition or oxidation of salts at high temperatures.

The source of ash in petroleum products is as follows: one is the soluble mineral salt brought by crude oil, which is left in heavy residual oil during distillation; the other is mixed in the refining process, for example, in acid and alkali. The metal salt (such as sodium sulfate, sodium carbonate, etc.) produced during refining is not removed, or the clay particles that have not been filtered during the treatment of white clay; the third is the equipment for refining (especially acid-base refining) and storage and transportation. Metal compounds produced by corrosion; Fourth, metal salt additives added to improve the quality of lubricating oil, such as some detergent dispersants, anti-oxidation and anti-corrosion additives. Lubricating oil also increases ash during use due to corrosion and dust contamination of the metal in contact with the oil.

Determination of petroleum product ash has different meanings for different oil products.

For lubricating oils containing no additives, jet fuels, diesel fuel oils, etc., ash is used as an indicator for checking the degree of refining. If metal salt or white clay remains in the refining, the ash content is increased. Therefore, it is specified in the specification that the ash is not more than a certain amount. For example, jet lubricating oils have a ash content of not more than 0.005% and the like.

For some lubricating oils containing metal salt additives, the ash content is required to be no more than a certain value before the additive is added, and the ash content is required to be not less than another value after the additive is added. The amount of ash before the addition of the additive should be small to ensure proper refining. The ash after the addition of the additive is used to ensure that there are enough additives to meet the quality requirements of the lubricant.