It is appropriate for the gas phase heat transfer fluid system to adopt stop valves and control valves with sylphon seals. And the circulation pump should adopt shield pump and electromagnetic coupling pump which have no shaft seals.
When the running system needs fluid supplements, the cold heat transfer fluid should be injected into the expansion tank first and then be transferred into system main circulation by the expansion tank.
The physical properties of heat transfer fluid are density, viscosity, spontaneous ignition point, flash point, pour point, boiling range, specific heat capacity, thermal conductivity and vapour pressure etc. And the operation performance and mode of fluid are mostly based on its density, viscosity, specific heat capacity, thermal conductivity and vapour pressure.
We use the hydrogenated benzene as raw material, so the products have high purity, the content reaches to 99.9% or more, impurities and trace elements can be made according to the requirements of customers, the product can be used in heat carrier .industrial synthesis, liquid crystal, and the pharmaceutical industry.
The procedures of starting up heat transfer fluid system are to start circulation pump first and then ignite the system. The procedures of shutting down system are to stop heating first and then stop the circulation pump after the fluid temperature is dropping below 100℃.
The synthetic heat transfer fluids include alkylbenzene, alkyl biphenyls, benzyl and dibenzyltoluene, biphenyl/diphenyl oxide mixture, terphenyl and some hydrogenated terphenyl, alkyl diphenyl oxide, aliphatic hydrocarbon, poly-α-olefin, silicone oil and hydrofluorocarbon.
Based on the current technology, the maximum film temperature of heat transfer fluid can't be tested directly yet. Practical operations are according to the standard of GB 23971 Heat Transfer Fluid shown below:
For the fluid with maximum operation temperature below 320ºC(including320ºC ), the allowed maximum film temperature should be 20ºC higher than its maximum operation temperature.
For the fluid with maximum operation temperature beyond 330ºC (including330ºC), the allowed maximum film temperature should be 30ºChigher than its maximum operation temperature.
Thermal stability of heat transfer fluid is the indicator to differ from other oils based on its operation and safety performance, which has great influence on fluid types and categories. The test of fluid thermal stability defines its maximum operation temperature and category.
The maximum operation temperature of heat transfer fluid is a test estimated value. The test is based on GB/T 23800 Test Method for Measurement of Thermal Stability of Heat Transfer Fluid. And the maximum operation temperature of tested sample is under the condition of deteriorating rate should be less than 10% (mass fraction).
The heat resistance and oxidation resistance of heat transfer oil is decided by the molecular structure, not maintained by adding antioxidants, the best of foreign antioxidants will decompose at 280 ºC , the best of the domestic antioxidant will decompose at 220 ºC. Different molecular structure determines different heat resistance and oxidation resistance.