Atomic layer deposition (ALD) is a gas-phase coating technique that can be used to coat nanoparticles in a fluidized bed reactor. ALD is based on the alternating supply of two precursors, which makes it an inherent dynamic process. We discuss a multi-scale, multiphase mass transfer-diffusion-reaction model capable of predicting the evolution of surface coverage of particles at different local operating conditions. The dynamic ALD-reactor model can be extended with operational scenarios. The reactor design combined with the scenarios has many degrees of freedom, yielding ample opportunities to optimize the process with efficient utilization of precursors.