Pyrolysis-gasification of biomass using nickel modified catalysts: The effect of the catalyst regeneration on the product properties

Abstract

In this work, agricultural biomass waste (maize) was used as raw material in a pyrolysis-gasification process with the presence of nickel-loaded zeolites, CaO and Al2O3. Henceforward, the reusability and the deteriorating effect of the catalysts are important to be analysed, therefore the catalysts were reused for ten regeneration cycles. During the measurements, the effect of temperature, catalysts and the regeneration cycles of catalysts were also investigated, as well as the components of the gaseous product. At first, the proper temperature was determined in the 1st (200–800 °C) and the 2nd (500–700°) reactor zone, where 400 °C and 700 °C, while for the regeneration 800 °C was chosen. Throughout the regeneration cycles in case of Ni/ZSM-5 lighter hydrocarbons was increased while that of the carbon monoxide and carbon dioxide was decreased. In the presence of Ni/CaO the amount of carbon dioxide decreased until the 3rd regeneration cycle, while carbon monoxide and hydrogen was decreased till the 10th cycle. Regarding the Ni/Al2O3, the amount of CO2 and CO was significantly decreased at each cycles, while in case of Ni/Clinoptilolite reduction was observed in hydrogen and carbon dioxide, however not only the amount of carbon monoxide but the syngas yield increased remarkably. Due to the mentioned results, the Ni/Clinoptilolite has an effective syngas enhancing and carbon dioxide capturing effect, even with low pyrolysis temperature.