In order to slow down the formation of coke and extend the mission of using heat transfer oil , measures should be taken from the following aspects:
1. Select a suitable grade of heat transfer oil and regularly monitor its physical and chemical indicators.
Heat transfer oil is divided into grades according to the highest use temperature. Among them, mineral heat transfer oil mainly includes three grades L-QB, L-QC and L-QD. The appropriate grade should be selected according to the maximum heating temperature of the heating system. "Standard thermal fluid. At present, the recommended maximum operating temperature and actual measurement results of some commercially available heat-conducting oils vary greatly, which is misleading to users. Safety accidents occur from time to time and should be brought to the attention of customers! The heat-conducting oil formulated from refined base oil with excellent thermal stability and high-temperature antioxidants and anti-scaling additives should be selected. Among them, high-temperature anti-oxidants can effectively delay the oxidation and thickening of the heat-transfer oil during operation; high-temperature anti-scalants can dissolve the coke in the furnace tubes and pipelines, disperse them in the heat-transfer oil, and finally pass the bypass filter of the system Filter it to keep the furnace tubes and pipes clean. After half a year or one year of use of the heat transfer oil, the four indexes of viscosity, flash point, acid value and residual carbon should be tracked and analyzed. When two of the indexes exceed the specified limits, some new oil should be considered or replaced completely. oil.
2. Reasonable design and installation of heating system
The design and installation of the heat transfer oil heating system should strictly follow the design rules for hot oil furnaces formulated by relevant national departments to ensure the safe operation of the heating system.
3.Regulate the daily operation of the heating system
The daily operation of the heat transfer oil heating system should strictly implement the safety technical supervision regulations of the organic heat carrier furnace formulated by the relevant state departments, and monitor the change trend of the temperature and flow rate of the heat transfer oil in the heating system at any time.
In actual use, the average temperature at the exit of the heating furnace should be at least 20 ° C lower than the maximum operating temperature of the heat transfer oil.
The temperature of the heat transfer oil in the expansion tank of the open system should be lower than 60 ° C, and the maximum temperature should not exceed 180 ° C.
The velocity of the heat transfer oil in the hot oil furnace should not be lower than 2.5 m / s to increase the turbulence of the heat transfer oil, reduce the thickness of the stagnation bottom layer and the convective heat transfer thermal resistance in the heat transfer boundary layer, increase the convection heat transfer coefficient, and strengthen Purpose of fluid heat transfer.
4. Cleaning of heating system
The thermal oxidation and thermal polymerization products first form a polymerized high-carbon viscous substance, which is attached to the pipe wall. Such substances can be removed by chemical cleaning. The high-carbon viscous material further forms incomplete graphitized deposits, and chemical cleaning is effective only on the portion that has not yet been carbonized. Fully formed graphitized coke. Chemical cleaning of such substances has not solved the problem, and mechanical cleaning is mostly used abroad. In use, it should be checked frequently. When the formed high-carbon viscous substances have not been carbonized, users can purchase chemical cleaning agents for cleaning.