Can you distinguish the three forms of thermal oil deterioration?
September 17, 2022
1. Thermal deterioration When the heat transfer oil is in a long-term high temperature operating environment, the carbon chain in the molecule will be broken, resulting in the decomposition of the compound into gas, low molecular compound (low boiler) and free radicals. The free radicals polymerize with other molecules to form high-molecular-weight polymers (high boilers). These reactions not only make the color of the new heat transfer oil gradually deepen until it turns black, but also the thermal stability, thermal conductivity, flash point, kinematic viscosity and other physical and chemical properties of the pyrolysis or polymerization products change, which affects the use of heat transfer oil. performance.
2. Oxidative deterioration After the heat transfer oil is in contact with the oxygen in the air, it will oxidize to form an organic acid, which can further promote the polymerization reaction. As the temperature rises, the oxidation rate will also increase, resulting in an increase in the viscosity of the heat transfer oil, and the color of the new oil changes from light yellow to dark brown, and then to black. The generated organic acid will have a certain corrosive effect on the equipment when it comes into contact with water. 3. Deterioration of mixed foreign matter 1) The mixed impurities may become catalysts to catalyze the decomposition and polymerization of oil products; 2) The mixed impurities may react directly with the heat transfer oil to generate decomposition products and polymers; 3) The mixed water will gasify at high temperature, resulting in unstable operating pressure of the system, and even cause an overpressure accident in severe cases; 4) The mixed impurities will deposit at high temperature, block the pipeline, affect the safe operation, and some even force the system to stop running.
Therefore, the heat transfer oil in use should be tested regularly, the degree of deterioration should be grasped in time, and necessary improvement measures should be taken to prevent some serious accidents and unnecessary economic losses caused by the deterioration.
