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

Abstract

SUMMARY 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.

Enhanced Reduction of Few-Layer Graphene Oxide via Supercritical Water Gasification of Glycerol

“…Non-catalytic routes require temperatures above 650 °C and longer residence times for complete gasification of glycerol [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 ]. As for the catalytic process, homogeneous catalysts [ 53 , 54 , 57 , 58 , 59 , 60 , 61 , 62 ] such as Na 2 CO 3 , H 2 SO 4 , K 3 PO 4 , K 2 CO 3 , KOH or NaOH have been used to improve the carbon to gas conversion and the yield to hydrogen by means of the water-gas shift reaction (WGS; CO + H 2 O ↔ CO 2 + H 2 ). Heterogeneous catalysts based on transition metals such as Ni, Ru, Pt, Co, Cu or Zn [ 51 , 52 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ] as well as on activated carbon [ 49 ], offered high selectivity and recyclability.…”

Conversion of residues and by-products from the biodiesel industry into value-added products

“…Supercritical water has the ability to act as an acid/base catalyst, dissolve non-polar organic compounds, and react with other compounds (Tapah et al 2014). The application of supercritical water gasification in crude glycerol has been evaluated in the presence of KOH and Fe 2 O 3 -Cr 2 O 3 as catalysts (Yang et al 2013;Tapah et al 2014). Catalytic supercritical water gasification improved the Syngas quality by reducing biochar impurities and increasing the amount of combustible gases, especially H 2 .…”

“…Catalytic supercritical water gasification improved the Syngas quality by reducing biochar impurities and increasing the amount of combustible gases, especially H 2 . However, KOH did not act as a catalyst; in fact, KOH acted as a reactant in the process and generated K 2 CO 3 as the product (Yang et al 2013).…”

Supercritical water gasification of glycerol for Hydrogen production using response surface methodology

“…For these reasons, and in order to produce hydrogen, several researchers have studied gasification in supercritical water glycerol experimentally [20][21][22][23][24], but very few researchers have carried out optimization studies on this biomass. From our bibliographic research only F.Yan et al [30] studied the supercritical water gasification of crude glycerol, using the central composite experimental design to optimize hydrogen production from crude glycerol, and to study the effect of glycerol concentration, temperature and KOH concentration. So, usually, optimization studies of supercritical gasification considered three parameters in their used experimental design.…”