Ni@ZrO2 yolk-shell catalyst for CO2 methane reforming: Effect of Ni@SiO2 size as the hard-template.

This paper reports the usage ratio of TEOS and Zr(OBu)4 on the formation of Ni@ZrO2 yolk-shell for dry reforming of methane. From XPS analysis, the ZrO2 hollow shell texture is demonstrated to be [TEOS]/[Zr(OBu)4] dependent due to different sizes of SiO2 produced. It found that an adequate ratio of [TEOS]/[Zr(OBu)4] improves the catalytic conversion of dry reforming of methane. It (Ni@ZrO2-SiZr-7.7) shows 90% conversion for CH4 and 93% for CO2 at a WHSV of 72,000 mLgcat-1h-1 for 50 h at 800 °C with TOFCH4 of 8.7 s-1. It proposed that the changes in surface Si/Zr and gradual interconnecting pores contributed to its activity and stability. These finding's potential to be utilized in other high-temperature reactions.

Chemical structure analysis and fast micro-pyrolysis study of hydrochar derived from hydrothermal treatment of municipal solid waste.

Hydrothermal treatment (HTT) experiments were conducted at 210○C and 230○C with 30, 60 and 90 min residence times. Fourier transform infrared spectroscopy (FT-IR) and 13C solid-state nuclear magnetic resonance (NMR) were employed to elucidate the effect of HTT on the chemical structure of municipal solid waste. FT-IR results clearly demonstrate that decarboxylation and aromatization reactions occurred during HTT. Fewer types of carbon skeleton structures were observed in the 13C solid-state NMR of hydrochars. The aliphaticity yield increased from 74.84% to 91.57% with increasing experiment parameters. In addition, the aromatization reaction was more dramatic in the early stage time, while carbonyl compounds decomposed during the HTT process. Pyrolysis gas chromatography mass spectrometry analysis showed that HTT had positive effects on the simplification of the pyrolytic gas component. In addition, all hydrochars were significantly inhibited to the formation of aromatic compounds with a minor relative peak area of 19.89%. Moreover, hydrochars obtained at a relatively low temperature could achieve a higher yield of hydrocarbons, and hydrocarbons could be partly purified after the HTT process. Overall, the available values of fast pyrolysis products were upgraded by the HTT process.

Thermal behavior and general distributed activation energy model kinetics of Lignite-Chinese herb residues blends during co-pyrolysis.

In this work, the pyrolysis behavior of lignite, Chinese herb residues (CHR) and their blends were explored by thermogravimetric analysis. The co-pyrolysis improved the pyrolysis characteristic of lignite, leading to an increment of index D. Analysis results showed that 30%-50% of CHR add ratio was the appropriate choice for co-pyrolysis with lignite. It was clarified that synergetic effects between lignite with CHR occurred during the co-pyrolysis treatment. And the promoting effects were dominated at 240 °C to 310 °C, while it turned to inhibiting effects at 315 °C to 355 °C. The pyrolysis kinetic evolution was adapted by a new general distributed activation energy model with four pseudo-components. The simulation results demonstrated an excellent match with the adjusted coefficients Radj2 over 99.97%. In addition, G-DAEM further considered A-E kinetic compensatory effect. The outcomes enriched the applicability of this model in thermal process of other fuels.