Method of operating a fluid bed reactor

1. A method of operating a three-phase slurry reactor, the method including

feeding at a low level at least one gaseous reactant into a vertically extending slurry body of solid particles suspended in a suspension liquid, the slurry body being contained in at least two vertically extending shafts housed side by side within a common reactor shell, each shaft being divided into a plurality of vertically extending channels at least some of which are in slurry flow communication and the slurry body being present in at least some of the channels, at least some of the shafts and/or channels being at least partially defined by heat exchange surfaces;

allowing the gaseous reactant to react as it passes upwardly through the slurry body present in at least some of the channels of the shafts, thereby to form a non-gaseous and/or a gaseous product;

allowing any gaseous product and/or unreacted gaseous reactant to disengage from the slurry body in a head space above the slurry body;

withdrawing any gaseous product and/or unreacted gaseous reactant from the head space; and

maintaining the slurry body at a desired level by withdrawing slurry or suspension liquid or by adding slurry or suspension liquid.

2. The method as claimed in claim 1 , in which the channels of a shaft are defined by vertically extending divider walls, with the divider walls of a shaft being generally parallel to each other, and divider walls of adjacent shafts being generally perpendicular to each other.

3. The method as claimed in claim 1 , in which slurry flow communication between channels in a shaft containing the fluidised or slurry body only occurs at top and/or bottom ends of such channels.

4. The method as claimed in claim 1 , in which the solid particles are catalyst particles for catalysing the reaction of the gaseous reactant or gaseous reactants into a product.

5. The method as claimed in claim 4 , in which the reaction is Fischer-Tropsch hydrocarbon synthesis.

6. The method as claimed in claim 1 , in which at least some individual shafts each have a gaseous reactant inlet, the method including feeding the gaseous reactant or reactants, or a recycle gas to these individual shafts independently from the feed to another shaft.

7. The method as claimed in claim 1 , in which at least two of the vertically extending shafts are vertically spaced, with an upper end of a lower shaft being below a lower end of an upper shaft.

8. The method as claimed in claim 7 which includes allowing slurry to pass downwardly from a high level in the slurry body in the upper shaft to a lower level of said upper shaft, and/or which includes allowing slurry to pass downwardly from a high level in the slurry body of the lower shaft to a lower level of said lower shaft.

9. The method as claimed in claim 7 , which includes feeding recycle gas at an elevated level into the reactor, so that said recycle gas passes only through the upper shaft or upper shafts and bypasses the lower shaft or lower shafts.