Slurry phase apparatus

A method of operating a slurry phase apparatus includes feeding one or more gaseous reactants into a slurry body of solid particulate material suspended in a suspension liquid contained inside a vessel. The one or more gaseous reactants are fed into the slurry body through a gas distributor having downward facing gas outlets and are fed towards a fluid impermeable partition spanning across the vessel below the gas distributor. The partition divides the vessel into a slurry volume above the partition and a bottom volume below the partition. A differential pressure is maintained over the partition between predefined limits by manipulating or allowing changes in the pressure in the bottom volume by employing a pressure transfer passage establishing flow or pressure communication between the bottom volume and a head space above the slurry body.