Optimization of hydrogen production from supercritical water gasification of crude glycerol-byproduct of biodiesel production

Abstract

Supercritical water gasification of crude glycerol for hydrogen (H2) production is one possible use of crude glycerol from biodiesel production. In this study, a series of central composite designed experiments were conducted to investigate the reforming of crude glycerol for producing a H2 rich gas. A mathematical model defining the effect of glycerol concentration, reaction temperature and KOH concentration was developed with response surface methodology and was used to improve the H2 yield. The study revealed that the optimum reaction conditions for producing H2 were 500°C, 7 wt.% glycerol concentration and 2.39 mol L-1 KOH concentration. The corresponding pressure was 45 MPa. Under these optimized reaction conditions, the H2 mole fraction yield in the gaseous product was 27.9 ± 0.22 mol%. The mole fraction yields of other gas products (CH4, CO and CO2) were small compared to that of H2. Copyright © 2012 John Wiley & Sons, Ltd.