HYDRODESULFURIZATION OF ATHABASCA FLUID COKE - CONVERSION AND MECHANISM

Hydrodesulfurization of Athabasca (Syncrude) fluid coke was studied fo r particle sizes of -74 + 53, -53 + 44 and -44 mu m using a quartz rea ctor. Five flow rates of hydrogen from 1.2 x 10(-6) to 2.5 x 10(-6) m( 3)/s were investigated with from 0.45 to 1.0 g of coke. Gas production - time profiles for H2S and CH4 were obtained at temperatures from 97 3 to 1073 K for each particle size range. Desulfurization rates were f unctions of particle size and temperature. Results agree with predicti ons of the shrinking core model, the rate being controlled initially b y the gas film and chemical reaction resistances followed by control d ue to diffusion of hydrogen through the increasing ash layer. Below 99 8 K, the apparent activation energy was determined to be 293 kJ/mol . K, while at temperatures between 998 and 1073 K it was 29 kJ/mol . K.