Dissolution of polycyclic aromatic hydrocarbons in supercritical water in hydrogen production process: A molecular dynamics simulation study

Catalytic Pyrolysis of Waste Polyethylene Using Combined CaO and Ga/ZSM-5 Catalysts for High Value-Added Aromatics Production

“…On one hand, it prevented the pyrolytic gas from entering micropores and overly cracking and producing large amounts of low carbon. On the other hand, it also prevented aromatization reactions between pyrolytic gas and strong acidic sites in the microporous structure, which would make it unable to be released from the microporous structure and generate carbon deposition , that would delay the catalyst deactivation . In summary, Ga loading provided active metal sites for cracking and aromatization of pyrolytic gas.…”

A Molecular Dynamics Simulation Study on the Diffusion Coefficients of the •OH, •H, and •HO2 Free Radicals Related in the Hydrogen Production Process in Supercritical Water

“…In fact, the ring opening of polycyclic aromatic hydrocarbons at the char interface is a controlled step. 2,3 This is an important means to strengthen reactions. However, char particles have a boundary layer, and these components can only reach the interface through molecular diffusion, 13−15 so it is also necessary to study the diffusion coefficients of free radicals.…”

“…Supercritical water (SCW) has both a pressure larger than 22.1 MPa and a temperature larger than 374.3 °C. − Many researchers have investigated and explored SCW properties and SCW gasification processes. SCW exhibits different physical properties from those of ambient liquid water including high diffusivity, low viscosity, density, and dielectric constant, and notably, organic substances and various gases could be completely dissolved in a SCW environment. − …”

“…Meanwhile, the solubility of hydrocarbon radicals in a SCW environment had been applied by MD simulation, which was beneficial to understand the thermal cracking of hydrocarbons in a SCW environment. In fact, the ring opening of polycyclic aromatic hydrocarbons at the char interface is a controlled step. , This is an important means to strengthen reactions. However, char particles have a boundary layer, and these components can only reach the interface through molecular diffusion, − so it is also necessary to study the diffusion coefficients of free radicals.…”

Effects of Alkaline Metals on the Reactivity of the Carbon Structure after Partial Supercritical Water Gasification of Coal

“…The primitive utilization method, direct burning of carbonaceous fuel with oxygen in air, causes greenhouse gas emission and serious air pollution because of the impurities of the fuels . Over the last decades, supercritical water (SCW) treatment of carbonaceous energy carriers has attracted high expectations as an alternative process to utilize the complex materials, and the technology is further classified as supercritical water gasification (SCWG), , supercritical water oxidation (SCWO), and supercritical water liquefaction (SCWL) to fulfill the adaptability to feed and the requirement of products. − The properties of water change drastically when crossing its critical point, the reduced viscosity and density guarantee a better diffusion in the organic matrix to facilitate reaction, and the change in dielectric constant makes it a good organic solvent to disperse the polymers and suppress the polymerization to promote conversion efficiency. − …”