A fluidized bed reactor comprising a reaction column having a fluid portion; a gas inflow means for flowing a gas upwardly from the fluid portion of the reaction column; a particle feed means for feeding particles to the fluid portion of the reaction column; a cyclone capable of separating particles from the gas flowing upwardly from the fluid portion of the reaction column, the cyclone being located within the reaction column and being in communication with the gas flowing upwardly, wherein the cyclone comprises a cyclone body having an inlet, a gas outlet, and a particle drop port; and a particle discharge pipe having an upper part connected to the particle drop port of the cyclone body, and a lower part, wherein the particle discharge pipe is located substantially outside of the reaction column.