HTF heat transfer in two basic ways: in the initial boiling point or below the boiling temperature of the liquid phase heat transfer mode; in the gas phase at a temperature above the boiling point of the heat transfer mode. The so-called maximum temperature refers to preheat conduction system efficient and safe operation of a direct relationship with a temperature limit, that the highest temperature and maximum film temperature. Refers to the maximum temperature in the recycle line from the heater out of the measured maximum allowable temperature of the main body. If the actually measured temperature is higher than this temperature, the main body of a large number of cleavage occur. Maximum film temperature is within the fluid flowing through the heater tube in contact with the heater boundary maximum allowable temperature, this temperature is equal to the inner pipe wall heater temperature. When the temperature is higher than the actual film temperature, a large amount of the liquid boundary layer cracking will occur, in general, the maximum allowable temperature plastic film measuring high temperatures up to about 20 ℃. In actual use, HTF brand, the technological requirements of the mainstream body temperature is lower than the highest temperature of the selected product HTF, from the design point of view to ensure that the temperature inside the heater pipe below the maximum film temperature. HTF GB GB23971-2009 in HTF determination about quality changes in the course of the two, one is thermal oxidation stability in Appendix C, and the other is the thermal stability of GB / T 23800 Professional HTF, two test methods in the process of changes in oil heating carbon residue indicators did not play its due role in the forward-looking herald. Especially thermal oxidation stability, at 175 ℃ * 72h after high HTF, also allow residue 50mg / 100g of existence, we think this is unreasonable, this residue is allowed to form carbon residue and sludge matrix. Professional HTF HTF _ _ Mianyang Fengqiu County Taihang Chemical provided by Fengqiu County Taihang Chemical Co., Ltd. Fengqiu County Taihang Chemical Co., Ltd. (www.hndaoreyou.com) strong, credible, in Xinxiang of fuel oil and other industries has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Fengqiu County Taihang Chemical Co., Ltd., and you hand into the brilliant, for a better future!