Kindly advise us on the type of gasket we need for the lid of a stainless steel pilot plant reactor operating at 500C in the pyrolysis of plastics to prevent vapour leakage.
Following Based materials that can be used between +500⁰C and +1200⁰C.
1. Ceramic, mica and clay
2. Ceramic Woven Fibre above +5000C
3. Upper temperature of approximately +500⁰C the graphite are then used to create a seal using materials such as graphite sheeting (graphite can be used up to 800⁰C in a non-oxidizing atmosphere) or spiral wound gaskets and ring type joints.
4. Very high (above +500⁰C) a gasket that as a graphite or mica is the best spiral wound gaskets.
5. Thermiculite -150⁰C to + 1000⁰C.
Hello James,
A brushable, impregnating high temperature sealant can be used to produce a suitable gasket in conjunction with woven glass-fibre, silica fibre or 3M 'Nextel' fibre non-woven textile materials, and essentially seals well against gas/fluid emission.
A suitable sealant material is 'Deacon 770-L' (viscous liquid/suspension)
see: https://www.deaconindustries.com/
The effective lifetime of the seal will depend upon actual temperatures in use and should be useable for runs of a few hours at 500C. Other materials supplied by Deacon can be used at higher temperatures.
Hi James, using woven silica (silica cloth or resin free woven fiber glass) would be your best bet. Most elastomers would not stand up to anything above 400 C for more than a few minutes at best. Best not to use gasket makers to secure to your vessel and just lay the gasket between the reactor and the lid before you clamp them shut. High density kaowool would also work if you can get your hands on it.
A laminated graphite is best. Been using them for years on gasifiers and pyrolysers. Good to 700°C Buy in the UK from James Walker, Cockermouth
https://www.jameswalker.biz/de/products/35-supagraf-reg-laminated-s10
Thanks all for your useful info on the type of heat resistant gasket needed for pyrolysis.
J A Omoleye
The link share by Prof. Cordner Peacocke was quite insightful https://www.jameswalker.biz/de/products/35-supagraf-reg-laminated-s10
Insightful responses. I learned from them. Thank you.
In our laboratory, we used a 1 mm thick copper sheet gasket. The outer diameter of the gasket is 72 mm.
Before installing it, it must be annealed: heat up to red and quickly immerse it in water.
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