Thermal oil has the properties of resistance to thermal cracking and chemical oxidation, good heat transfer efficiency, fast heat dissipation, and good thermal stability. As an industrial oil heat transfer medium, thermal oil has the following characteristics: it can achieve high operating temperatures under almost atmospheric pressure conditions. It can greatly reduce the operating pressure and safety requirements of high-temperature heating systems, and improve the reliability of the system and equipment; It can meet the process requirements of heating and cooling at different temperatures within a wider temperature range, or achieve the process requirements of high temperature heating and low temperature cooling simultaneously using the same thermal oil in the same system. It can reduce the complexity of the system and operations; Omitting the water treatment system and equipment improves the thermal efficiency of the system and reduces the maintenance workload of equipment and pipelines. It can reduce the initial investment and operating costs of the heating system; In the event of a system leak caused by an accident, combustion may occur when the heat transfer oil meets an open flame, which is a problem that exists in the heat transfer oil system compared to the water vapor system. But under the condition of no leakage, the operational safety of the thermal oil system is higher than that of water and steam systems because it operates under low-pressure conditions. Compared with another type of high-temperature heat transfer medium molten salt, thermal oil has an absolute advantage in terms of heat transfer medium price and service life when operating at temperatures above 400 ºC. However, it is at a significant disadvantage in other aspects, especially in terms of system operation convenience. Its chemical properties are more stable and it is not as easy to ignite and burn as light oil.