Graphite/SiC faces for caustic soda.

[AngelM]

Is it posible to use faces of graphite/SiC instead of SiC/SiC as an alterantive in case or not having these ones?

Some chemical incompatibility?

Does it depends on the pressure fluid?

 

[flexibox]

Avoid resin impregnated carbons. If you use a carbon ensure that you have either permanent or intermittent water quench to avoid crystallization.. If you have crystal build up you may experience wear and hang up issues.

 

[AngelM]

If the caustic soda concentration is 50% and considering that the crystallization temperature is of 12ºC for this concentration, according to some documentation I read (?), If the product temperature is about 25ºC, is it necessary the quench?

I haven't found any documentation about the crystallization temperature of the caustic soda with regard to the concentration and pressure.
Can you help me on this?

 

[flexibox]

AngeIM
There are other things to consider, all mechanical seals leak. The leakage rate is dependent on a number of factors such as seal diameter, pressure, speed, face flatness etc. Leakage is approx 5 to 10 cc/hr. As this leakage takes place the liquid will evaporate and the crystals will start to form. Eventually the crystals will build up and depending on the seal design you may experience seal Hang Up! I would recommend using sil vs sil with EPDM elastomers and an external spring design seal. When you experience crystallization flush it with water. Remember that the crystallization occurs on the atmospheric side of the seal hence the quench..

Trust this helps