On the dry gas seal of high-temperature centrifugal fans
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Hello everyone, I have a fan here that operates with SO3 gas at a temperature of around 250 degrees. The dry gas seal on this fan breaks down frequently. Could you help analyze the reasons for this and suggest solutions? The possible reasons are: 1. The dew point temperature of SO3 gas is around 120 to 150 degrees, and since the shaft seal gas is only heated to around 70 degrees, the sulfuric acid that may form could damage the seal ； 2. The material used for sealing is carbon fiber F4; it can withstand temperatures of up to 250 degrees only, and it deforms at higher temperatures, resulting in leaks ； 3.。 . . . . . I’m not sure if the reason I thought of is correct; so how can this be solved? Replace the heater for the shaft seal gas? Change the material of the seal? What material is suitable for such operating conditions? I earnestly request your guidance; thank you very much
You can ask the manufacturer whether silicon carbide can be used. Additionally, ensuring a continuous supply of seal gas should also be an important measure to prevent damage to the dry gas seal.
Of course, continuous supply of seal gas needs to be taken into consideration, but no problems will arise; the seal gas is supplied from instrument air. If there are issues, production itself cannot be ensured, let alone the operation of the fans. To prevent the seal gas pressure from fluctuating and even dropping below the process gas pressure, the seal gas pressure is usually set much higher; of course, this also has some drawbacks.
Looking at the post, we have similar problems as well