It seems that sodium, magnesium and iron are responsible for the increase of the high turbo expander vibrations values, in a FCC power recovery unit, these variables are very difficult to control because they depend on feedstock and temperatures. The particles that leave the regenerator and the 3rd stage separator, when they reach the rotor blades of the turbo expander cause scaling, erosion and deposition of tiny particles. Some chemical compounds combined each other can act as glue deposits that stick over the rotor blades causing the machine unbalance. These situations can lead to frequent shutdowns, loss of production and even the turbo expander damage. To avoid the catalyst sticking on the expander rotor blades, when vibrations increase, we inject walnut shells, and when walnut shells are not enough, we are obliged to do thermal shocks with steam and water. In the past, our expander thermal shocks were done within 3 to 4 months intervals, but now, the frequencies of thermal shocks are between 15 days to one month. What are the others practice and remediation on this subject?

Thanks

Luis Marques