Lignin Gasification over Charcoal-supported Palladium and Nickel Bimetal Catalysts in Supercritical Water

Abstract

Charcoal-supported palladium and nickel binary salt catalysts showed higher lignin gasification activity than the linear combination activities of the individual monometal catalysts, indicating a bimetallic synergetic effect. XRD and EXAFS analyses revealed that Pd–Ni alloy structures were formed during the lignin gasification over the catalysts, which provided higher activities for the gasification than the individual monometal catalysts.

Catalytic Transformation of Lignin for the Production of Chemicals and Fuels

“…Gasification of lignin produces synthesis gas (syngas) which is a mixture of hydrogen and carbon monoxide. − The synthesis gas can then be converted into liquid fuels by two different commercial processes: Fischer–Tropsch synthesis or methanol/dimethyl ether synthesis . Several reports in the literature use supercritical water (374 °C, 218 atm) for gasification of lignin. ,− In terms of thermal efficiency, this process offers the advantage of eliminating the need to dry the biomass, which is especially important for lignin with high moisture content. Four main processing units are needed for the above two routes: a lignin material gasifier, a gas cleanup unit, a water–gas shift reactor in certain cases to produce hydrogen with the coformation of carbon dioxide, and finally a syngas converter.…”

Alternatives for Chemical and Biochemical Lignin Valorization: Hot Topics from a Bibliometric Analysis of the Research Published During the 2000–2016 Period

“…Nevertheless, compared with homogeneous alkali catalysis [242], heterogeneous catalysts based on transition and noble metals have advantages. Ni-Co/Mg-Al catalysts have been evaluated and have demonstrated high flexibility and potential for gasification [243], while noble metals showed higher activity for the gasification, following this order: Ru > Rh > Pt > Pd > Ni [244][245][246][247]. All the component technologies needed for the production of biofuels or chemicals through gasification at a biorefinery are either already commercially used or are undergoing pilot-scale demonstrations ( Figure 6) and the corresponding technical and economic models have been developed for the simulation and evaluation of the complete process [248][249][250].…”