When the heat transfer oil is used beyond its thermal stability limit, it will undergo rapid thermal cracking. Its thermophysical property parameters have a very important influence on the heat transfer efficiency and medium temperature change in the furnace. Due to the over temperature cracking of the heat transfer oil, the coking of the boiler tube will be caused, the heat transfer will be deteriorated, and the furnace tube will burst.
The heat transfer oil leakage in the furnace is formed, so the design of the heat transfer oil boiler should meet the thermal stability conditions of the selected heat transfer oil. The use of its thermal physical parameters to stop the heat transfer calculation, structural design and safety evaluation of the boiler should prevent the overheating of the heat transfer oil at the internal task position of the boiler.
The liquid film temperature of heat transfer oil in the boundary layer of boiler heating surface should be strictly limited. During boiler design, the maximum heat flow density on the radiant heating surface in the furnace shall be limited according to the maximum allowable liquid film temperature of the selected heat transfer oil, and the flow rate and temperature of the heat transfer oil in the furnace tube shall be controlled. In addition, the layout of the radiation heating surface of the heat transfer oil boiler should prevent the direct erosion of the flame on the furnace tube. Because when the boiler is running, if part of the flame in the furnace directly washes the furnace tube, it will lead to the increase of the heat flow density of the pipeline and the rise of the temperature of the liquid film of the heat transfer oil.
Leakage of heat transfer oil in boiler will cause fire or explosion. The main reason for the leakage of heat transfer oil in the boiler is that the coking of heat transfer oil causes the furnace tube to overheat and burst, the welding defect of the furnace tube, or the problem of the boiler structure and the furnace tube data. Once the leakage of heat transfer oil occurs in the boiler, how to extinguish the extinguished fuel in the furnace and cut off the supply of heat transfer oil and air as soon as possible becomes the key to control the expansion of the accident and reduce the hazard level.