Common items and testing instruments for oil analysis and inspection

Viscosity:

Viscosity is a measure of the viscosity of a fluid, a representation of the fluid flow force on its internal friction phenomenon. The larger the viscosity, the larger the internal friction force, the larger the molecular weight, the more hydrocarbons combined, and the greater the force. Viscosity is of decisive significance for various lubricating oils, quality identification and determination of use, as well as combustion performance and consumption of various fuel oils. At the same distillation temperature, the petroleum products with alkane as the main component have low viscosity and better viscosity-temperature, that is, the viscosity index is higher, that is, the viscosity changes less with temperature; The oil with more aromatics) has higher viscosity, that is, the viscosity-temperature is poor; the oil with more colloid and aromatics has the highest viscosity and the worst viscosity-temperature, that is, the viscosity index is low. Viscosity is commonly expressed as kinematic viscosity, in mm2/s. Heavy fuel oil has a high viscosity. After preheating, the kinematic viscosity reaches 18~20mm2/s (40℃), which is conducive to the uniform injection of fuel by the injector. 

Carbon residue:

Carbon residue is a char-black residue formed by heating the test oil in the crucible of the carbon residue measuring device according to the specified conditions until the test oil is evaporated and decomposed. The electric furnace method stipulates that the furnace temperature is kept at 520±5℃ and the residue after evaporation is decomposed. Generally, diesel residual carbon stipulates that the test oil should be distilled to 10% residual before it is evaporated and decomposed. Called 10% distillation residue carbon residue, this 10% distillation residue carbon residue value is much larger than the result of full burning residue carbon, and heavy fuel oil is required to be full carbon residue. Large low-speed diesel engines can use heavy fuel oil containing 10% carbon residue. The residual carbon value affects the coking and charring of the combustion chamber. However, the wear of the cylinder and piston depends not only on the amount of residual carbon, but also on the hardness of the carbon. The carbon deposit with high sulfur content is hard and hard, and the wear is large

Distillation:

Distillation range refers to the temperature range from the initial boiling point to the final boiling point, which is obtained by distilling oil under specified conditions. It is mainly used to determine the composition of light and heavy fractions of oil products, and to control product quality and performance. Distillation range is an important indicator to ensure the rapid vaporization and combustion of diesel in the engine combustion chamber. The full distillation range of light diesel oil is 160~365℃; when heavy diesel oil is used in low-speed diesel engines, it has sufficient atomization and evaporation time, and there is no strict requirement for distillation range, generally 250~450℃. blended fuel oil has been used