Alcoxycle: A novel route for glycerol reform into H2 and COx in separate stages

Abstract

In this paper, it is proposed a new route, named “Alkoxycle”, for the conversion of glycerol from biodiesel production into H2 and CO/CO2 in different and separate stages. In this process, glycerol first reacts with NaOH to form an alkoxide that, in a second step, undergoes controlled thermal decomposition. Analyses of glycerol:NaOH precursor mixtures (molar ratios of 1:1, 1:2, 1:3 and 1:5) by TG, XRD, SEM, TEM, Raman, total carbon and GC–MS showed that the decomposition of the alkoxide at 400°C leads to the formation of three fractions: liquid, gas and solid. The liquid products were formed only in very small amounts whereas an important gas fraction (12–16wt%) was produced consisting mainly of H2 (95% selectivity). In the second stage, the solid products (70–86wt%) consisting of Na2O, carbon and mostly Na2CO3 can be decompose by heating at 700°C to procuce CO2 and especially CO. At the end of the Alcoxycle process, the NaOH used in the reaction and also the NaOH present in the biodiesel glycerol can be recovered and reused.