Selection of strong alkaline seal gaskets
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This post was last edited by Against the current and wind on 2023-11-13 at 14:31. There is a reactor in which the reaction mixture contains a strong base, KOH (potassium hydroxide), at a concentration of around 30–35%. The reaction temperature is 230–260°C, and the pressure is negative, at approximately -0.02 Mpa. May I ask what type of gaskets should be used at all the connections and interfaces of this equipment?
When selecting reactor gaskets, factors such as the corrosiveness of the medium, operating temperature, and pressure should be taken into consideration. For the strongly alkaline medium you mentioned (30–35% KOH), the high reaction temperatures (230–260°C), and the negative pressure environment, it is recommended to use gaskets of the following material types: 1. Polytetrafluoroethylene (PTFE): PTFE possesses excellent chemical stability, as it hardly reacts with any chemicals. It also has a wide temperature range (from -200°C to +260°C), making it suitable for use in environments with strong acids and bases. Additionally, it features good creep resistance and a low friction coefficient. 2. Expanded polytetrafluoroethylene (ePTFE): This material also possesses excellent chemical resistance, offers better flexibility and sealing properties than regular PTFE, and is suitable for use in high-temperature environments with strong alkaline conditions. 3. Fluororubber (FKM): Fluororubber exhibits good heat resistance, oil resistance, and chemical resistance; it is also resistant to alkalis at room temperature, but it may be affected at high temperatures, so the actual operating conditions must be taken into consideration. These materials also need to be combined with the type of sealing gasket used, such as flat gaskets, groove gaskets, or metal-wound gaskets, to ensure that the required pressure and sealing performance are met. At the same time, given that the working environment is under negative pressure, the vacuum performance of the sealing gasket must also meet the required standards. When selecting gasket materials, it is recommended to consult a professional sealing parts supplier for detailed advice; custom services may also be required depending on the specific circumstances. Thorough testing must be conducted to verify the performance of the selected sealing material under the corresponding operating conditions. .
Under such process conditions and medium conditions, only wound gaskets made of 304 stainless steel and flexible graphite can be used.
Use flexible graphite stainless steel wound gaskets
Stainless steel gaskets probably won’t work. Consider PTFE-impregnated graphite
Thank you to everyone above. :victory:
The second floor is quite professional, but sadly it’s a fake professionalism. The owner’s strong alkaline medium has reached 260 degrees; yet they still use gaskets whose maximum temperature tolerance is not even 260 degrees. Are you trying to be funny or are you an expert in this field? In this case, a metal wound gasket is the best choice