This book offers a step-by-step calculation procedure to design fluidized bed reactors which involve a chemical reaction between gas and solid phases. It includes the key equations of hydrodynamics and mass transport of fluidization engineering. Thus, it can be a sufficient textbook for process engineers and graduate students who are dealing with fluidized beds where both fluidizing gas and solid particles participate in a chemical reaction. While the attempt has been made to introduce an easy-to-follow design method, individual flowcharts for relevant calculation of hydrodynamic, mass transport and heat transfer of the process are illustrated for computer programming purposes. A specific example, which involves reaction of superheated steam with copper chloride particles in a fluidized bed reactor as part of a thermochemical hydrogen production plant, is presented to show the reader typical profiles of key process parameters at various operational conditions.