Catalyst in a slurry phase reactor is rejuvenated and uniformly distributed in said reactor using a substantially vertical draft tube fully immersed in the slurry which utilizes a rejuvenating gas injected substantially near the bottom of the substantially vertical draft tube whereby catalyst near the bottom of the slurry phase reactor is drawn up the draft tube and discharged from the top of the draft tube near the top of the slurry phase in said reactor.
A reversibly deactivated, particulate catalyst in a slurry hydrocarbon synthesis slurry is rejuvenated by circulating the slurry from a slurry body through (i) a gas disengaging zone to remove gas bubbles from the slurry, (ii) a catalyst rejuvenation zone in which a catalyst rejuvenating gas contacts the catalyst in the slurry to rejuvenate it and form a rejuvenated catalyst slurry and, (iii) back into the slurry body. Removing at least a portion of the gas bubbles improves the rejuvenation process.
Hydrogen containing tail gas from a hydrocarbon synthesis reactor is used as a hydrogen containing catalyst rejuvenating gas. If CO is present, the CO content, is less than 10 mole % of the gas and the H.sub.2 to CO mole ratio is greater than 3:1. At least a portion of the water and liquid hydrocarbons are removed from the tail gas, before it is used to rejuvenate the reversibly deactivated catalyst.
A reversibly deactivated hydrocarbon synthesis catalyst in a hydrocarbon synthesis slurry is rejuvenated by passing the slurry into a lift pipe external of the reactor in which it contacts a hydrogen containing rejuvenating gas. The hydrogen rejuvenates the catalyst particles in the slurry and forms a mixture of a rejuvenation offgas which may contain catalyst deactivating species and a rejuvenated catalyst slurry. This mixture is passed into a gas separating and removal vessel in which the offgas is separated and removed from the slurry, which is then returned back into the reactor or elsewhere. The rejuvenating gas also acts as a lift gas to create slurry circulation up through the lift pipe and into the gas removal vessel.
A downcomer for producing at least two slurries having different solids and gas concentrations from a single three phase slurry of particulate solids and gas bubbles in a slurry liquid has two or more concentric gas and solids disengaging zones, each having an open fluid conduit depending from an orifice in the bottom. The dowwncomer is useful in a slurry hydrocarbon synthesis process for forming a catalyst and gas reduced slurry which is passed to a liquid filter to remove hydrocarbon liquid from the slurry reactor.
A reversibly deactivated hydrocarbon synthesis catalyst in a hydrocarbon synthesis slurry is rejuvenated by successively passing the slurry through at least two rejuvenation stages external of the slurry reactor, each of which comprises a rejuvenation zone followed by an offgas removal zone. This is accomplished by using a lift pipe outside the reactor into which slurry from the reactor is passed and contacts a catalyst rejuvenating gas to partially rejuvenate the catalyst particles and form a rejuvenation offgas. The gas and slurry mixture are passed into a vessel in which the gas is removed from the slurry. Rejuvenation gas is bubbled into the slurry in the vessel to further rejuvenate the catalyst. A gas removing downcomer removes gas from the slurry in the vessel before it is passed back into the reactor. The rejuvenation gas also acts as a lift gas in the lift pipe.
