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Conclusions
Results-Effect of carbon type-Effect of ash minerals-Tar composition
Experimental-Char production &characterization-Tar Collection & analysis-Experimental setup
Contents
Introduction
IntroductionExperimental setup
ResultsConclusion
• Hydrogen is considered as an important fuel of the future. There has been a growing interest to find a sustainable source for hydrogen production.
• Gasification is one of the effective thermochemical conversion processes of biomass energy for producing a hydrogen rich gas, however tar formation is a major problem.
• Carbonaceous char can act as a catalyst to degrade the tar components to useable gases.
Research goal:
• To investigate the use of waste-derived char as a catalyst for hydrogen production and tar cracking during the pyrolysis/reforming of biomass.
Introduction
Experimental setup
ResultsConclusion
EFFECT OF BEDTYPE
Tar cracking in theAbsence of steam
NO charTyre charRDF char
Date stones char
EFFECT OF CHAR ASH/with steam
Hydrogen-rich syngasproduction &tar reforming
Tyre char
Acid treated tyre char
Introduction
Experimental setup
ResultsConclusion
Char production
Water cooled condenser
To exhaust
N2
Furnace
Samplecrucible
waste
ThermocoupleT
Dry Ice cooled condensers
Water trap
Gas sampling
point
Conditions:√ Char: Waste Tyres, RDF, Date stones.√ Pyrolysis temperature: 800°C.√ Carrier gas: N2(Also de-mineralised pyrolysis tyre char was investigated)
Introduction
Experimental setup
ResultsConclusion
T
Char
Thermocouple
BiomassN2
Mass flow controller
Exhaust
Condenser system
Tar & gases
Gas sample bag
Experimental setup
Liquid product
Tar/oil+H2O
Karl-Fischer Titration
Water removal-Na2SO4 bed
Evaporation of DCM
GC-MS analysis
Water content
Tar
Pyrolysis temperature=500°C Biomass : char ratio=1:1
Introduction
Experimental setupResultsConclusion
Without char Tyre char RDF char Date stones char
Temperature (°C) 800 800 800 800Residual Biomass Char (wt.%)
23 23.5 23.5 24
Liquid (wt.%) 28.5 8.5 17 24.5Tar (wt.%) 15.3 4.6 7.6 13.9Water (wt.%) 13.3 3.9 9.4 10.6
Gas yield (wt.%) 46.6 57.5 59.5 50.6Gas composition (vol.%)CO 42.3 34 29.9 40.1H2 19.6 29 34 25CO2 16.2 20.3 21.7 16.2CH4 15.1 12.1 10.5 12.8C2─C4 6.7 4.7 3.9 5.9
Mass balance (%) 98 89.5 99.9 99.1
Influence of waste derived pyrolysis char on the product yield from the pyrolysis-gasification of biomass
Introduction
Experimental setupResultsConclusion
100 120 140 160 180 200 220 240
0
5
10
15
20
25
30
Wei
ght p
erce
ntag
e (%
)Molecular weight (g mol-1)
Date seeds char RDF char Tyre char NO char
Without char Tyre char RDF char Date seeds char0
10
20
30
40
50
60
70
Rel
ativ
e co
ncen
trat
ion
(%)
Phenols PAHs
Tar composition
• The main compounds detected were phenolic compounds and polycyclic aromatic hydrocarbons (PAH).• The fraction of polyromantic hydrocarbons decreased significantly with the use of tyre char compared to
the experiment without char.
Introduction
Experimental setupResultsConclusion
Effect of carbon type over tar composition at a cracking temperature of 800 °C
Introduction
Experimental setupResultsConclusion
Tyre char Acid treated tyre charTemperature (°C) 700 800 900 700 800 900
Mass balance based on the biomass sample + water (wt.%)
Gas 12.1 16.6 33.0 11.6 15.8 26.1
Liquid 82.8 76.87 61.4 84.5 79.9 69.5
Biomass char 5.6 5.8 5.5 5.5 5.9 5.5
Mass Balance 100.5 99.2 99.8 101.6 101.0 97.5
Tyre char recovered (%) 100.0 91.0 82.5 101.0 98.0 85.5
Mass balance based on the biomass sample (wt.%)
Gas 50.0 67.1 131.6 48.9 63.1 106.8
Biomass char 23.0 23.3 22.0 22.5 23.5 22.5
Gas characterization
HHV (MJ Kg-1) 48.3 52.5 66.1 27.9 44.3 63.6
H2 yield (mmol g-1) 8.4 12.5 39.2 2.7 8.6 30.5
H2/CO (mol mol-1) 1.31 1.37 2.11 0.37 0.75 1.41
The influence of simultaneous gasification of pyrolysis gases and char
Introduction
Experimental setupResultsConclusion
0
10
20
30
40
50
0
20
40
60
80
100
700 800 900 700 800 900
Hyd
roge
n yi
eld
(mm
ol g
-1)
Gas
com
posi
tion
(vol
.%)
Temperature (C°)
H2 CO CO2 CH4 CnHm H2 Yield (mmol/g)
Acid treated tyre charOriginal tyre char
Gas compositions and hydrogen yield with original and acid treated tyre chars
Introduction
Experimental setupResultsConclusion
H2, coke, CnHm,…
coke
Functional groups(FG)CO,CO2
Cracking of FG
Formation of FG
Active sites for tar conversion
Metal speciesFunctional groups
0
10
20
30
40
50
60
70
80
90
Original Tyre char Acid treated Tyre char
Peak
are
a (%
)
Class 2 Class 3 Class 4 Class 5
Concentration of classified tar compounds
Tar Analysis
• Carbonaceous chars simulates the cracking of tar in gasification syngas.
• Hydrogen production increased significantly with the use of tyre char in the 2nd stage to be about 39.20 mmol g-1 biomass due to the simultaneous reactions of tar reforming and char gasification.
• The difference in hydrogen production between the original and the acid treated tyre chars suggests that metals present in tyre char have a significant catalytic effect in enhancing the water gas shift, tar reforming and char steam reactions.
• Waste-derived chars would represent a low cost source of catalytic char material for hydrogen production during biomass gasification.
Introduction
Experimental setupResultsConclusion