In many metal-catalyzed conversion processes of hydrocarbons at atmospheric pressure a carbonaceous overlayer quickly builds up at the catalyst covering nearly the whole surface. However, the metal still remains catalytically active. Several models have been proposed over the years to explain the crucial role of the carbonaceous overlayer during the conversion of hydrocarbons. The model presented here contemplates adsorbate effects, which means that surface carbon modifies the dehydrogenation activity of Pt. A hydrocarbon reaction mechanism on platinum, including C-1 and C-2 species, is established. The mechanism is based on elementary reactions offering the opportunity of using the same mechanism for a wide range of applications. It is also applied to extended simulations of higher pressures and smaller flow velocities revealing increased C2H6 yields under these conditions.