Patent ID: RE39073

Claim:
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 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 p >5 μm, to the height, H>3m, of the expanded liquid in the column by operating with a catalyst settling velocity, U s , and dispersion coefficient, D, such that 0.5 ⁢ ( U s - U L ) ≤ D H , where ⁢ ⁢ H > 3 ⁢ ⁢ m U s = 1 18 ⁢ d p2 ⁢ ρ s - ρ l μ ⁢ gf ⁡ ( C p ) , where ⁢ ⁢ d p > 5 ⁢ ⁢ µ ⁢ ⁢ m and (c) maintaining plug flow in said column by operating with a gas phase velocity, U g , expanded liquid height, H, and dispersion coefficient, D, such that U g ≧0.2D/H, where H>3 m, U g >2 cm/sec wherein ρ s =effective density of the particles ρ l =density of the liquid μ=viscosity of the liquid f(C p )=hindered settling function C p =volume fraction of solids in the slurry (liquid plus solids) U L =liquid velocity along the column H=height of the expanded liquid in said reactor g=gravitational constant d p =diameter of particles m=meters.