Catalyst in a slurry phase reactor is rejuvenated 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, control over the rejuvenation temperature in the substantially vertical draft tube being achieved by means of insulating the draft tube and/or fitting the draft tube with heating or cooling means.
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.
A reversibly deactivated, particulate catalyst in a 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 and increase its density, (iii) a downcomer which feeds the gas reduced, dense slurry into the bottom of a rejuvenating tube and applies a positive hydrostatic pressure to the tube, (iii) a catalyst rejuvenation zone in which a catalyst rejuvenating gas, which also acts as a lift gas, contacts the catalyst in slurry to form a catalyst rejuvenated slurry and, (iv) back into the slurry body. Removing gas bubbles prior to rejuvenation improves the rejuvenation efficiency and the downcomer reduces the amount of rejuvenation gas required to maintain slurry circulation through the tube.
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.
A reversibly deactivated, particulate catalyst in a hydrocarbon synthesis slurry is rejuvenated by circulating the slurry from a slurry body through a rejuvenation zone in which hydrogen contacts the slurry and rejuvenates the catalyst to form a rejuvenated catalyst slurry and an offgas which contains catalyst deactivating species. The offgas is separated and removed from the rejuvenated slurry before it is passed back into the slurry body. This avoids or minimizes contamination and recontamination of the slurry body with the deactivating species produced by the rejuvenation process.
Continuous process for the production of prevalently heavy hydrocarbons starting from synthesis gas in the presence of a gas phase, a liquid and a solid catalyst, the above process being carried out using a bubble column, characterized in that the bubble column internally has: (a) at least one draft-tube; (b) at least one device for the inlet of the synthesis gas; (c) at least one device for the inlet of the regenerating gas; (d) at least one device for activating/interrupting the stream of regenerating gas; (e) optional devices suitable for minimizing the mixing of the synthesis gas with the regenerating gas.
