This document discusses a study on carbon deposition during steam reforming of glycerol using a bimetallic Co-Ni/Al2O3 catalyst. Glycerol is a byproduct of biodiesel production that can be converted to syngas via steam reforming, but carbon deposition must be minimized for process efficiency. The study examines steam reforming of an aqueous glycerol solution over a temperature range of 773-823K using a tubular reactor. Various characterization techniques are used to analyze the catalyst before and after reaction, including thermal gravimetric analysis, total organic carbon content analysis, Fourier transform infrared spectroscopy, and X-ray diffraction.

1. Renewable energy
Carbon Deposition on Bimetallic Co-Ni/Al2O3 Catalyst
during Steam Reforming of Glycerol
Chin Kui Cheng, Say Yei Foo, Adesoji A. Adesina
Reactor Engineering & Technology Group, School of Chemical Engineering,
The University of New South Wales
Sydney NSW 2052, Australia
INTRODUCTION AND MOTIVATION Aqueous Glycerol
Solution
• Climate change effects and sustainability Syringe
considerations have necessitated the development of Pump
new production technologies for energy and base Heating zone
chemicals from renewable resources Steam reformed H2, CO2, CO
• Syngas - a major base chemical and clean energy fuel
Flow
can be produced from biowastes rather than fossil feed Controller F F
Electric
• Glycerol (C3H8O3), the by-product of biodiesel Furnace
Vent
• For down-stream
P = 101.3 kPa
production is cheaply available and may be used as chemical processes
feed to a syngas process Map showing biodiesel plants in Australia T = 773 – 823 K H Argon GC 2
Tubular Manometer
Source: Biofuels Association of Australia
‡
• However, due to its high carbon content (40wt%),
Reactor • As fuel for engine
control and minimisation of carbon deposition during Excess glycerol is readily available Drierite bed
Condenser • Fuel cell application
catalytic steam reforming is vital to process efficiency from biodiesel industry as waste Schematic diagram illustrating the steam reforming set-up
Catalyst preparation Chemistry of glycerol steam reforming Post-reaction analysEs
Co-Ni/Al2O3 (b) TGA for gasification
+3H2O 4H2 studies
(2)
+ 7H2 3CO
(c) TOC for carbon
content analysis
(1)
Al2O3 support (d) FTIR analysis
3CO2 +3H2O (3)
Precursors C3H8O3 (Glycerol) (b) (e) XRD analysis
3CO2 (c) (d)
Drying/calcination
Titration 3H2
(a) Autosorb for BET
area and pore volume
Sieving
Deposition of carbon -2.2
Power-law modelling (823 K) Arrhenius plot Catalyst regeneration
-2.8
Glycerol
Steam
TOC profile at 823 K
-2.4
Slope = -0.2213
-2.9 TPR-TPO on used Al2O3 TPR-TPO on used Co-Ni/Al2O3
Slope = 0.5513
R2 = 0.934 EA = 40.9 kJ mol-1
R2 = 0.9532
R2 = 0.999
-2.6
ln(rcoking)
-3.0
ln (rcoking)
-2.8
-3.1
-3.0 -3.2
-3.2 -3.3
1 2 3 4 0.00120 0.00122 0.00124 0.00126 0.00128 0.00130
ln (Pressure) 1/T (K-1)
•The carbon deposition behaviour may be modelled by the
power-law expression: MS of gas-(used Al2O3) rxn MS of gas-(used Co-Ni/Al2O3) rxn
4920
T 0.56 0.22
•Total carbon content (TOC) profile shows rcarbon A exp Pglycerol Psteam
strong dependency of carbon deposition with • The inhibition effect of steam towards carbon deposition was
Pglycerol shown by the negative global power-order (-0.22)
•TOC shows relatively mild inhibition by the • Carbon deposition increased with reaction temperature. The
presence of steam, as shown by Psteam activation energy EA estimated as 40.9 kJ mol-1
Solid-state analysIs FTIR spectra XRD pattern
Effect of TOC on physical properties Conclusions
• Carbon deposition is strongly influenced by
Pglycerol but weakly inhibited by Psteam
• Most of the carbon was deposited on the Al2O3
• The presence of at least two types of carbon
•Sample A: calcined fresh catalyst, B: •Carbon peak was detected at 2θ = species was evident from TPR-TPO studies
Al2O3 employed in blank run, C: used 26o for used Al2O3 and Co-Ni/Al2O3
catalyst, D: regenerated catalyst • Complete gasification was achieved (TPR-TPO)
• Carbon deposition resulted Regenerated catalyst did not have •
in reduced BET area and pore • The spectrum band at 1015 cm-1 due to carbon peak, consistent with FTIR Acknowledgements
volume of used catalysts C-O and C-C stretch mode. The band at spectra
1650 cm-1 represents C=C mode. The CKC is grateful for UIPA scholarship from UNSW
-1 due to O-H mode
• Wider peaks for used and
band at 3500 cm
regenerated catalysts indicates while SYF is a recipient of APA
• A and D showed similar band possible sintering effect
Corresponding author:
TOCAT6/APCAT5 Prof. Adesoji A. Adesina
a.adesina@unsw.edu.au
JULY 18 – 23 , 2010 SAPPORO CONVENTION CENTER, SAPPORO JAPAN Tel.: +61 2 9385 5268; Fax: +61 2 9385 5966