Simulation analysis of Co-Pyrolysis of oil shale and wheat straw based on the combination of chain reaction kinetics and improved CPD models

Highlights: • Proposing a co-pyrolysis model of oil shale with biomass. • Constructing more than 10 pathways and reaction kinetics equations. • The distributions of the products were accurately predicted using this model. In order to fill in the blank of the prediction model about the co-pyrolysis of oil shale with biomass, we proposed a novel co-pyrolysis model based on chemical structure using improved chemical percolation devolatilization (CPD) with chain reaction kinetics (CRK). Three basic elements of aromatic cluster, aliphatic bridge, and oxygen-containing bridge are chosen as the representative structure units for building the simplified pseudo-grid model. According to the pyrolysis characteristic, we divided the model to five processes: the breakage of bridge bonds, the adsorption of free radicals, the reaction of aliphatic chains, the aromatization reaction and the cross-linking reaction, and described it through 14 reaction pathways and 18 reaction kinetic equations. The predicted results are compared with experimental results of fixed bed and thermogravimetry (TG) analysis, while the error is within a reasonable range indicating the accuracy and rationality of our model. We believe that this paper provides a deep understanding of the co-pyrolysis processes and discovery of the distribution characteristics of different kinds of pyrolytic intermediates and free radicals at an atomic level beyond what laboratory experiments could achieve.