A review on the application of non-thermal plasma (NTP) in the conversion of biomass: Catalyst preparation, thermal utilization and catalyst regeneration

Abstract

A brief review of non-thermal plasma (NTP) technology as a new technology for the thermal conversion of biomass is presented in this paper. Three aspects of the entire process are generally considered from the viewpoint of (i) biomass pretreatment, catalyst preparation assisted by NTP prior to the thermochemical conversion; (ii) thermochemical conversion of biomass or its derivates assisted by NTP; and (iii) regeneration of deactivated catalyst after thermochemical conversion. A stable catalyst is a requisite for any industrial application of catalysis to make it commercially viable. However, there is still a challenge to achieving a controlled morphology, which majorly affects the catalytic performance in the thermochemical conversion of biomass or its derivates, and template removal and metal loading by NTP are focused. At the same time, the reforming of tar, catalytic pyrolysis of biomass, gasification of biomass, and upgrading of bio-oil assisted by NTP are given great attention, including the reaction mechanism, product distribution, etc. In the thermochemical conversion of biomass, the deactivation of catalysts easily occurs in the process due to sintering, coke accumulation, and other reasons. The deposited coke is oxidized to generate gaseous products by introducing oxidizing gas, which is generally used in the regeneration of catalysts. Generally, this article reviews the plasma-assisted preparation of catalysts used in the thermochemical conversion of biomass, the application of plasma technology in the thermal conversion of biomass, and the regeneration of deactivated catalysts in plasma-assisted thermochemical conversion of biomass.