The main goal is to develop and evaluate global reaction mechanisms. The optimization is done using two methods; Laminar Flame Speed and Perfectly Stirred Reactor. The global reaction mechanisms consists of a few reactions with the purpose to predict similar flame temperature, flame speed and major emissions compared to detailed reaction mechanisms. In this work, the optimization of the global reaction mechanisms is done through modifying the Arrhenius coefficients. This is executed by coupling the CHEMKIN software with the multi objective design tool modeFRONTIER. The global reaction mechanisms are implemented in CFX and results from CFD combustion simulations are compared with Sandia Flame D.