A ball valve apparatus 10 for clearing an obstruction in a conduit is disclosed. The ball valve apparatus 10 incorporates a wear resistant choke tube 42 in the downstream opening 40B of the ball 36. The choke tube 42 can be two to four times smaller than the opening 40A on the upstream side of the ball 36. Removal of catalyst through the choke tube results in lower velocity of the flow through the bore of the valve, thereby reducing wear and erosion. In normal operation in an FCC unit, catalyst is extracted from the system through the choke tube 42. When the conduit becomes plugged, the ball valve apparatus 10 can be cycled into a fully opened position, thereby creating a high flow rate of fluid through the conduit, removing any existing obstructions.