Slurry bubble column (C-2391)

A method for optimally operating a large diameter three phase (gas, liquid, solid) slurry bubble column having a diameter greater than 15 cm for Fischer-Tropsch synthesis over a supported cobalt catalyst in which solid particles are fluidized in the liquid phase by bubbles of the gas phase, comprising:

• (a) injecting the gas phase into said column at an average gas velocity along said column, U.sub.g >2 cm/sec, such that the flow regime is in the substantial absence of slug flow;
• (b) fluidizing the solid supported cobalt catalyst particles of average diameter, d.sub.p >5 .mu.m, to the height, H>3m, of the expanded liquid in the column by operating with a catalyst settling velocity, U.sub.s, and dispersion coefficient, D, such that ##EQU17## and (c) maintaining plug flow in said column by operating with a gas phase velocity, U.sub.g, expanded liquid height, H, and dispersion coefficient, D, such that
• U.sub.g .gtoreq.0.2D/H, where H>3m, U.sub.g >2 cm/sec
• wherein
• .rho..sub.s =effective density of the particles
• .rho..sub.l =density of the liquid
• .mu.=viscosity of the liquid
• f(C.sub.p)=hindered settling function
• =volume fraction of solids in the slurry (liquid plus solids)
• U.sub.L =liquid velocity along the column
• H=height of the expanded liquid in said reactor
• g=gravitational constant
• d.sub.p =diameter of particles
• m=meters.