The application of a catalytic membrane process for the removal of dilute concentrations of ammonia resulting from the gasification of coal has been investigated. Mathematical simulations have been conducted for an experimental reactor comprising a thin but continuous layer of a Pd-Ag alloy deposited on a porous substrate. Data for the permeation of hydrogen through the composite membrane were determined experimentally. A rate equation for ammonia decomposition over Ni/Al2O3 catalysts was coupled with the experimentally determined hydrogen permeation rate data to obtain results for various reactor configurations. The results presented here have demonstrated the superiority of such a composite membrane reactor system over other methods. Furthermore, complete destruction of the ammonia was achieved for the relatively short space times considered in this study and can also be applied in operations carried out under gasification conditions.