Behavior of hydrogen H in titanium hydride TiHx is studied with the help of macrokinetic modeling by the free hydrodynamic package OpenFOAM. Modeling of hydrogen in the delta-TiHX is performed taking into account the nonlinear dependence of H diffusion from both the temperature and the hydrogen concentration. Two experiments on the thermal desorption of hydrogen isotopes of titanium hydride were chosen for fitting the effective recombination constants. Several methods of global minimization of target function are employed in fitting procedure. The comparison of the used methods is provided and discussed. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.