Differential pressure governor

Controlled catalyst circulation is one of the most important prerequisites for trouble-free operation of the FCC unit. Uniform circulation is ensured by controlling the differential pressure between the reactor and regenerator. The differential pressure in the existing plant is controlled by a differential pressure governor adjusting the position of the double slide valve upstream of the orifice chamber. 

A differential pressure controller acts in split range on the inlet control valve and the bypass valves. The differential pressure governor is retained as the standby and backup system. 

Under normal operations, the existing differential pressure governor is switehed to manual and the double slide valve is wide open. This valve must be suffieiently opened so that, even in the event of an emergeney expander trip, the entire flue gas flow ean pass through the double slide valve without the regenerator diseharge pressure inereasing to nonpermissible levels. 

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