Guichon’s new Transfer Line valves (TLV03), provide reliable, long lasting tight shut-off without friction between discs and seats. Guichon Valves proposes a valve design with double disc sliding gate and sleeve combination to reduce coke ingress.
In the petrochemical industry, ethylene is obtained either from rich natural gas ethane (C2H6) by pyrolysis or cracking at high temperature (USA) or from naphtha from fractional distillation of petroleum (Europe) by steam cracking.
Cracking is accomplished by heating ethane to a temperature greater than 800°C in the cracker furnace. These heaters suffer from a phenomenon of coke accumulation over the pipework and valves. The sticky coke particles can drop into the valve body during the opening-closing phase and damage the sealing system by adhering to its surfaces. Moreover, its hardness is similar to cement and sometimes jackhammers are used to remove it.
From time to time these deposits must be removed, without shutting down the process completely. In decoking operation the TLV and the decoke valve is used. This operation is critical as the ethylene, is a volatile substance with explosion risk, if it is vented to the atmosphere. The Guichon valves and the steam injection largely eliminate the risk of coke accumulation.