In part I of this paper a new fluidized bed reactor module was presented for the simulation of a bubbling fluidized bed and of the riser of a circulating fluidized bed with the flowsheet simulation tool SolidSim so that several process models can easily be coupled. In the present part lithe newly developed fluidized reactor modules are connected to existing cyclone modules to simulate a complex coupled fluidized-bed process, the selective oxidation of n-butane to maleic anhydride in a riser-regenerator system [1,2]. The calculation results for a laboratory setup are found to be in good agreement with experimental data from the literature. The subsequent simulation of an industrial scale sized plant shows that a high solids recirculation rate is needed to achieve satisfying maleic anhydride yield. The usefulness of flowsheet simulation is demonstrated by further process simulation calculations with varied solids recovery systems. (c) 2011 Elsevier B.V. All rights reserved.