Electrically heated fluidized bed reactor and processes employing same

A method of carrying out an endothermic chemical reaction involving the use of at least one finely subdivided solid reactant in a fluidized bed reactor, wherein the reactor comprises a vessel assembly comprising at least one riser compartment and a downcomer compartment located adjacent each other and being interconnected at both their lower and upper end regions, said downcomer compartment having upper, central and lower regions;

• each of said compartments having associated therewith means for introducing fluidizing gas therein and containing electrically conductive fluidizable particles having an average particle size of about 0.004 to 0.12 inches (1 to 3 mm);
• at least a solid reactant inlet to the vessel assembly for a solid reactant in subdivided form, wherein said inlet communicates with said upper or central region of the down-comer compartment;
• at least one outlet communicating with the upper end regions of said compartment wherein spent fluidizing gas and accompanying reaction products are removed and electrodes associated with the vessel assembly and adapted to pass an electrical current through at least a selected zone of a fluidized bed therein, the method comprising:
• (a) introducing fluidizing gas into the lower regions of both the down-comer and riser compartments whereby in the down-comer compartment, the fluidizable particles are substantially in a state of incipient fluidization and the superficial fluidizing gas velocity in the riser compartment is higher than that in the down-comer compartment, to thereby cause movement of said fluidizable particles up the riser compartment and over onto the upper region of the down-comer compartment and a simultaneous downward movement of the fluidizable particles in the down-comer compartment;
• (b) introducing said at least one solid reactant through said solid reactant inlet to said upper or central region of said down-comer compartment, said reactant being in solid subdivided form and having an average particle size of less than about 0.004 inches (100 .mu.m), to thereby cause said reactant to become entrained with the fluidizable particles whereby said fluidizable particles move counter-currently to the flow of fluidizing gas;
• (c) passing an electrical current between said electrodes to heat, by resistive heating, said fluidizable particles;
• and
• (d) removing spent fluidizing gas together with reaction products accompanying same through the outlet.