Catalytic gasification with ethanol: a novel valorization technique for scrap tires

Abstract

Ethanol gasification of waste tires was investigated against pyrolysis in the presence of H-β zeolite and γ-Al2O3 catalysts. Non-catalytic gasification gave a much higher gas yield of 45.2% in comparison to a pyrolysis gas yield of 29% and increased the hydrogen content of the gas. Using a catalyst increased the gas yield during both pyrolysis and gasification from 29% to 34–35% and 50–52%, respectively. γ-Al2O3 was found to be more effective at catalyzing secondary pyrolysis reactions such as cracking, dehydrogenation, aromatization, and cyclization, especially when coupled with the excessive free radicals produced during ethanol gasification, resulting in a gas with 35 mol% hydrogen. H-β was found to enhance the formation of light alkenes such as propylene and ethylene during pyrolysis and gasification, respectively. The resultant syngas is suitable for use either as an energy alternative, or as feedstock for Fischer-Tropsch synthesis for the production of higher hydrocarbons.