The thickness of the PTFE liner is designed to be 2 mm. The reasons for the instability failure are as follows: the operating pressure of the equipment is slight negative pressure, and its vacuum degree is 195 mdash; 269 Pa. From the analysis of the designed lining strength, the crude distillation column lining can withstand a vacuum degree of 975 Pa negative pressure.
After winding, the raw steel does not directly contact the medium in the kettle to avoid corrosion of the steel wire by the medium.The crude distillation column kettle is the main production equipment for the hydrofluoric acid process of the fluorine material plant. According to the gas state equation: Several issues that should be paid attention to. Apply adhesive between the PTFE cutting board and the cutting board, and weld them together by resistance heating. Analysis of the causes of damage to the tetrafluoroethylene lining .
The lining of the crude distillation tower kettle adopts a structure formed by sintering the PTFE tape on the steel wire, which can improve the ability of the tetrafluoro lining to resist negative pressure. It is often used in a new carbon steel kettle. Further inspection found that the tetrafluoroethylene lining of the kettle section was not equipped with steel wire tires according to the design drawings, which greatly reduced its ability to withstand negative pressure; the PTFE-lined carbon steel shell did not have a 4mm diameter exhaust hole. In addition, a small hole with a diameter of 4 mm is opened on the shell near the flange for exhaust. Its process medium is highly corrosive water-containing HF gas, and the temperature is above 100 degrees, so the corrosion is quite serious.
There are three processing methods for this lining: The PTFE tape is wound on the mold, and then sintered. In less than a month, it will corrode and perforate and be forced to stop, and the steel-lined polytetrafluoroethylene (hereinafter referred to as tetrafluoroethylene) lining structure will also be damaged.1 The tetrafluoroethylene lining structure of the crude distillation column The tetrafluoroethylene lining is generally a loose lining structure, that is, the lining does not adhere to the surface of the equipment and there are gaps. From the analysis of the damage of the lining of the crude distillation tower, it is obvious that it is an unstable damage.
The fluorine lining does not add steel wire molds, so when the equipment is running, the gas in the gap between the lining and the steel shell expands due to the increase in temperature, which causes the pressure to rise. This article introduces the causes of damage to the lining and several problems that should be addressed. Use PTFE welding rod to weld the lining materials together. Damage analysis of the tetrafluoroethylene lining of the crude distillation tower kettle It was found from the remaining section of the kettle that the lining was severely separated from the steel shell, ptfe coated fiberglass adhesive tape Manufacturers the cross section of the lining was plum-shaped, and the carbon steel shell was basically intact