Mechanism of hydrogen production by catalytic pyrolysis of tire rubber based on molecular dynamics simulation

In this study, molecular dynamics simulation method was used to study the mechanism of hydrogen production by catalytic fast pyrolysis of tire rubber over Ni, ZSM-5 and Ni/ZSM-5. At the same time, it was compared with the previous experimental studies to verify the simulation calculation. The model was established by Material Studio, the transition state of the hydrogen generation path was searched by DMol3 module, and the catalytic pyrolysis process of adding Ni was simulated by CULP module. The simulation results indicated that the energy barrier of hydrogen generation path decreased with the addition of three catalysts, and the order of catalytic effect was Ni>Ni/ZSM-5>ZSM-5. The catalytic fast processing was divided into two stages:①the low temperature stage was the long chains released monomer compounds, which was mainly isoprene, styrene and 1,3-butadiene; and ②the high temperature stage was that free radical attacked monomer compounds to form small molecular structure. The addition of the catalyst in the low temperature stage was mainly manifested in speeding up the pyrolysis process and increasing the number of monomers in the low temperature stage. The pyrolysis temperature was reduced and the proportion of H2 increased with the addition of Ni catalyst. © 2022, Chemical Industry Press Co., Ltd.. All rights reserved.