The kinetic and physical laws developed in the first part of the study have been implemented in a modified version of the bubbling bed Kato and Wen model to represent multiwalled carbon nanotubes (MWCA7s) synthesis by catalytic chemical vapor deposition from ethylene as carbon source and using an Fe/Al2O3 catalyst. The absolute deviation for MWCNT productivity between experimental results of Part I and simulations is of 17.3% when only considering experiments for which the bed is mainly in bubbling regime. The influence of the main operating parameters on the evolutions with time of the species molar fractions, the weight of MWCNTs formed, and the bed characteristics has been numerically studied. Such capabilities can help designing new reactors. Finally, the model has been used for scale up purposes, by increasing the reactor diameter and catalyst weight. Simulations have shown that the process productivity could reach 74 tons/year of MWCNTs in a reactor 45 cm in diameter. (c) 2008 American Institute of Chemical Engineers AIChE J, 55: 465-474, 2009