Hydrogen production by means pyrolysis and steam gasification of glycero

Abstract

The objectives of this work were to optimize the variables affecting pyrolysis and steam gasification of glycerol (by-product formed during biodiesel production); and to characterize the gaseous phase formed, in order to carry out its energetic use. The studied operation variables were reaction temperature (700-900 ºC), water flow rate (0-0.173 g·min-1), glycerol flow rate (0.009-0.676 g·min-1) and carrier gas (nitrogen) flow rate (30-180 cm3 ·min-1). The most interesting phase (analyzed by gas chromatography) was the gas fraction. In this work, gas fraction was composed by H2, CH4, CO, C2H6, C2H4 and CO2. The main gas generated was the hydrogen. Its generation was favoured by steam presence and its yield was increased in 224% in relation with pyrolysis process (default of water steam). The better conditions for studied process were 800 ºC, 0.074 g·min-1 of water flow rate, 0.009 g·min-1 of glycerol flow rate and 60 cm3 ·min-1 of nitrogen flow rate. In these conditions, the volume of synthesis gas was 1.86 L·(gglycerol) -1 and its higher heating value (HHV) was 26.70 MJ· (kgglycerol) -1. This study indicated that the bio-glycerol is an excellent raw material in the obtaining of medium heating value gases. These gases could be used as fuel in industrial furnaces or domestic use.