1. Residual carbon is an indirect indicator of colloidal substances and unstable compounds in the oil. The larger the residual carbon, the more unstable hydrocarbons and colloidal substances in the oil. For example, if the residual carbon of the cracking raw oil is large, it indicates that it contains more colloidal substances and is easy to generate coke in the cracking process, which makes the equipment coke.

2. The residual carbon value can reflect the degree of refinement of diesel oil. The residual carbon value of diesel fuel is a function of its distillation range and refinement degree. The lighter the fraction of diesel, the deeper the degree of refinement, the smaller the residual carbon value; if the fraction is heavy and the degree of refinement is shallow, the larger the residual carbon value must be. It is important to determine the 10% residual carbon of diesel fuel vapor residue to ensure the production of high quality diesel fuel. The residual carbon value of diesel fuel in use will form carbon in the cylinder, resulting in poor heat dissipation, increased wear and tear of engine parts, shortening the service life of the engine. The residual carbon value of diesel fuel without amyl nitrate is useful for guiding the production of crude diesel fuel gas making.

3. The residual carbon value can also indirectly reflect the degree of refinement of the lubricant. Lubricating oil made of heavy oil containing more colloidal material has a higher residual carbon value.

4. The residual carbon value of raw materials can predict the coke yield. The greater the residual carbon value, the greater the residual carbon of the raw coking oil is measured, the greater the coke yield of the delayed coking process can be predicted. The larger the residual carbon value, the higher the coke yield.

5. Residual carbon is an important specification item of heat transfer oil in use. The residual carbon value indicates the degree of aging of the heat transfer oil, the residual carbon in the quenching oil is too large, will then generate black adhesion on the surface of the quenching oil, making it difficult to reprocess the product.