Characterization of olivine-supported nickel silicate as potential catalysts for tar removal from biomass gasification

Abstract

In this work olivine-supported nickel silicate, which was prepared by thermal impregnation is considered as a potential tar removal catalyst for cleaning the gas stream during biomass gasification. Previous work on Ni-olivine catalysts has shown that these catalysts have good activity for the tar-reforming reaction as well as good stability and tolerance to coking. In this work, various characterization techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, laser Raman spectroscopy, temperature programmed reduction, temperature programmed reaction, and subsequent temperature programmed oxidation are employed to reveal the properties of the catalyst surface and bulk as well as their relationship to catalytic activity. Higher thermal impregnation temperatures produce stronger interactions between the active component and support, leading to better coke tolerance. Relative amounts of reducible Ni, Fe species and surface Mg have an influence on catalytic behavior. Moreover, compared to olivine, the Ni 2 SiO 4 /olivine catalyst exhibits good catalytic activity for dry reforming, water gas shift, reverse water gas shift and methanation reactions, as well as the steam reforming reaction.

A highly carbon-resistant olivine thermally fused with metallic nickel catalyst for steam reforming of biomass tar model compound

“…The most exciting implication is that the carbon deposition rate is very low (less than 1%) when the S/C ratio is more than 0.88. Similar results were obtained in the literature, 22,25,46 which demonstrated the strong interaction between NiO-MgO solid solution and Fe-Ni alloy with the olivine structure during thermal fusion, promoting the resistance of carbon deposition. With the increase of steam added (S/C less than 1), the ratio of H 2 /CO becomes closer to the stoichiometric ratio of eqn (8).…”

Hydrogen‐rich gas production from catalytic gasification of pine sawdust over Fe‐Ce/olivine catalyst

“…It could be seen that higher catalytic temperature was favorable for the conversion of tar and the generation of H 2 . While high calcination temperatures could result in the sintering of Fe particle and deactivation of the active phase which lead to a decrease in catalyst activity . Cui Quan et al found that Fe/olivine calcinated at 900°C owned the largest reduction peak area and had the highest amount of reducible iron .…”

“…While high calcination temperatures could result in the sintering of Fe particle and deactivation of the active phase which lead to a decrease in catalyst activity. 27 Cui Quan et al found that Fe/olivine calcinated at 900°C owned the largest reduction peak area and had the highest amount of reducible iron. 28 Therefore, considering the results of gas yield, H 2 yield, LHV and economical, catalytic temperature and gasification temperature of 800°C was the optimum conditions for catalytic reforming of pine sawdust.…”

Nickel supported on iron-bearing olivine for CO2 methanation

“…However, the calcination temperatures of Ni/ olivine were generally as high as 1100 Ce1400 C to enhance the stability in these works. As a result, the NiO grafted with the support or integrated into olivine structure could hardly be reduced at a temperature well below 910 C [36,41,42] and predictably has little catalytic activity for CO 2 methanation [43]. Ni/olivine or NieFe/olivine prepared for methanation hasn't gained enough attention yet.…”