Atomic-Level Simulation Study of n-Hexane Pyrolysis on Silicon Carbide Surfaces

Abstract

Ethylene production plays a key role in the petrochemical industry. The severe operation conditions of ethylene thermal cracking, such as high-temperature and coke-formation, pose challenges for the development of new corrosion-resistant and coking-resistant materials for ethylene reactor radiant coils tubes (RCTs). We investigated the performance of ceramic materials such as silicon carbide (SiC) in severe pyrolysis conditions by using reactive force field molecular dynamics (ReaxFF MD) simulation method. Our results indicate that β-SiC surface remains fully stable at 1500 K, whereas increased temperature results in melted interface. At 2500 K, fully grown cross-linked-graphene-like polycyclic aromatic hydrocarbon coking structure on SiC surfaces was observed. Such coking was particularly severe in the carbon-side of the surface slab. The coking structures were mainly derived from surface atoms at the initial 3.0 ns, as a result of the loss of interfacial hydroxyl layer and further hydrothermal corrosion. The SiC substrate surface enhances the ethylene cracking rate and also leads to different intermediate-state compounds. Our fundamental research will have significant and broad impact on both petrochemical industry and academic research in materials science, petrochemistry, and combustion chemistry.

Interfacial bonding mechanism and joint weakness area of brazed SiC and Nb with AuNi filler alloy: First‐principles and experimental perspective

“…The composite structure composed of SiC and Nb will promote the lightweight and complex shaping of engineering structures. [4][5][6] For heterogeneity materials, brazing is a dependable connecting method. Brazing alloy serves as a bridge between SiC and Nb, connecting each other by reaction layers.…”

“…Nb metal with high toughness, high temperature resistance and corrosion resistance has been applied in numerous engineering fields, which can be a complementary material to SiC. The composite structure composed of SiC and Nb will promote the lightweight and complex shaping of engineering structures 4–6 . For heterogeneity materials, brazing is a dependable connecting method.…”

ReaxFF MD Simulations of Peptide-Grafted Gold Nanoparticles

“…Simulation methods, such as conventional molecular dynamics (MD), − Monte Carlo, , and discrete molecular dynamics , simulations, focus on the physical nonbonding interactions while neglecting possible chemical reactions, e.g., ionizable groups’ protonation/deprotonation equilibrium and thiol–Au interactions and chemisorption. The development of the reactive force field (ReaxFF), as a polarizable charge model based on the bond order, has made it possible to simulate chemical reactions, including combustion, , hydrocarbon pyrolysis, , thermal decomposition of polymers, the explosion of high-energy materials, , and the oxidation of solid surfaces and NPs . By allowing chemical bonds to form and break freely without fixing the rigid connectivity between atoms inside a molecule or fixing atoms’ partial charges, ReaxFF MD overcomes the deficiencies of conventional MD and the scale problem of quantum mechanics. , A recent study employed ReaxFF MD to study biomolecules, e.g., short peptides and small proteins in water .…”