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|Date 25.06.20101
Upgrading of Pyrolysis Oilwith Catalytic Hydrotreatment
Agnes ArdiyantiErik Heeres
|Date 25.06.2010
Lignocellulosic biomass(“woody biomass”)› Source: wood, grass, sawmill dust› Composition (in wt-%)1:
› Potential: 13 EJ (minimum) in 2030
2
softwoods hardwoods grassescellulose 40-44 43-47 40hemicellulose 25-29 25-35 35lignin 25-31 16-24 12extractives 1-5 2-8 13
1WUR; 2van Dam, 2007
|Date 25.06.20103
Lignocellulosic biomass – valorisation pathways
|Date 25.06.2010 28-10-09 | 4
Fast Pyrolysis Oil
Lignocellulosic biomass
Fast PyrolysisCondensables, Fast Pyrolysis Oil
Char
Volatiles
450-600 oC, 1-2 s
BTG, EnschedeBridgewater et al, Org. Geochem, 30,1999
|Date 25.06.2010
Fast pyrolysis oil5
› High oxygen content (up to 50%)
› Immiscible with petroleum products
› Unstable upon heating and storage (coke formation, repolymerization)Pyrolysis oil composition
C (wt%) 40.1
H (wt%) 7.6
O (wt%) 52.1
Moisture (wt%) 23.9
|Date 25.06.2010 28-10-09 | 6
Objective:Deoxygenation of Pyrolysis Oil
Fast pyrolysis oil DeoxygenationCo-feedstock for refineries (FCC, hydrocracking)
Catalyst, P, T
Fast pyrolysis oil
H2
Upgraded Oil
Gas
Water
Selected process: Catalytic Hydrotreatment
-(CHxOy)- + c H2 -(CHx)- + (H2O, CO2, CH4, CO)
|Date 25.06.2010
Desired product› Low oxygen content› Low viscosity› Low molecular weight› High aliphatic content› Low coking tendency
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|Date 25.06.2010 28-10-09
Catalytic hydrotreatment
Oxygen contentH/C, O/C ratioViscosityMolecular weightCoking tendency
CatalystHeating routeReactor design
Upgraded oil properties: Process variables:
|Date 25.06.2010
Heating route
9
|Date 25.06.2010
Why heating route?› Polymerization is very common! sticky,
gooey paste is produced, instead of a nice and liquid oil
› Pyrolysis oil contains 30 wt% sugar when heated: charring
10
Which condition should we apply to suppress this reaction?
|Date 25.06.2010 28-10-09 | 11
Pyrolysis Oil
› Thermal cracking releases O mainly as H2O and CO2
› Repolymerisation occurrs
› O is released as H2O, H2 is consumed
› Further consumption of H2 saturates the C-C double bonds and cracks the large molecules (similar to coal liquefaction)
HPTT HDO
Low H/C, High Mw
High H/C, Low Mw
175-225oC>250oC, H2, catalyst
>250oC, H2, catalyst
Hypothesis1,2
1 Gagnon, Ind. Eng. Chem. Res 27, 19882 Venderbosch, et al, J. Chem. Tech & Biotech, 85, 2009
|Date 25.06.2010 | 12
Experimental set-up
› 4 fixed-bed reactors in-series
› Feed: forest residue pyrolysis oil (VTT, Finland)
› Catalyst: Ru (5%)/C› H2 pressure: 200 bar› Variables: T, WHSV› Analysis:
Elemental composition, TGA, GPC, viscosity
1
2 3
4Feed vessel
PI
TIC
TIC
TIC
TIC
PI
cooler
Product vessel
KO vessel
PI
Vent
FI
QI
Heater 1 Heater2
Heater 3 Heater 4
MI
MI
Gas inlet
MFC
BTG, The Netherlands
|Date 25.06.2010 28-10-09
Effect of process conditions, visual observations
› High T in all 4 reactors Phase separation, clogging after 25 min
› Low T in all 4 reactors (‘Stabilization’) Phase separation at 225 oC or higher
› Low T in first reactors, high T at the end (‘Mild Hyd’) Phase separation, run for 3 days without clogging
› ‘2-stage Hyd’ (Hydrotreatment on ‘Mild Hyd’ organic product) Top organic layer formed, no clogging observed
Py-oil Mild Hyd 2-stage Hyd
|Date 25.06.2010 28-10-09
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
0.1
0.2
0.3
0.4
0.5
0.6
ato
mic
O/C
atomic H/C
Van Krevelen plot
Py-oil (dry)
Stabilization 175 oC
Stabilization 225 oC
Hydrogenation dehydration hydrogenation
Mild hydrotreatment 2-stage
|Date 25.06.2010
Why H/C and O/C?
15
HDO
HDO
Coke formationH/C = 0.5O/C = 0
H/C = 1O/C = 1/6
H/C = 1O/C = 0
H/C = 1.7O/C = 0
|Date 25.06.2010 28-10-09 | 16
0
200
400
600
800
1000
1200
10203040oxygen content (wt%)severity of process
Mw
(g
/mo
l)
0
5
10
15
20
25
30
resi
du
e (w
t%)
(1) (2) (3)
Physical properties during further hydrotreatment
stab Mild 2-stage
Mw and TGA
Correlation between Mw and residue weight (TGA)
Py-oil
Mw
residue (TGA)
|Date 25.06.2010
TG residue, as a function of H/C and O/C
TGA residual weight [%] = 81.523 – 57.164 H/C + 32.25 O/C
17
Design-Expert® Sof tware
residue21.5869
2.8166
X1 = B: O/CX2 = A: H/C
0.11
0.22
0.34
0.45
0.56
1.24
1.30
1.36
1.42
1.48
0
7.25
14.5
21.75
29
re
sid
ue
B: O/C A: H/C
Estimation of physical properties is possible
|Date 25.06.2010
Change of composition: solvent fractionation
› Sugar, HMM decreases after reaction, leaving the apolar, low molecular weight components behind!
18
|Date 25.06.2010
1H-NMR (organic phase)
› Groups: aldehydes, aromatics, carbohydrates, methoxy, aliphatics
19
Pyrolysis oil
Stabilization 175 oC
Mild hydrotreatment
2nd hydrotreatment
|Date 25.06.2010
Upgraded oil as co-feeding
› Comparable yields are found for the petroleum feed (Long Residue) and mixture of Long residue+upgraded oil
de Miguel Mercader, App. Cat. B 96, 2010
In catalytic cracking
|Date 25.06.2010
Summary on heating route› Van Krevelen plot indicates the occurence of three
subsequent processes: hydrogenation, dehydration, hydrogenation
› During hydrotreatment, the Mw, viscosity, and TGA residue-weight of product oil increase during the stabilization step, then decrease at more severe conditions.
› High H/C and low O/C of the organic product is desired› The change of composition can be followed by e.g. solvent
fractionation and 1H-NMR.› Upgraded oil can be used as co-feeding in refinery units
21
|Date 25.06.2010
Catalyst
22
|Date 25.06.2010
What type of catalyst?› No specific reaction homogeneous is not an
option› Heterogeneous catalyst: Which support, active
metal, preparation?
23
|Date 25.06.2010
Support› Regenerable› Stable in water, acid, high temperature:
ZrO2, SiO2 potential
› High specific surface area (less important)
24
Active metal› Any metal with hydrogenation activity› Interesting: noble metals (Ru, Pd, Rh), Ni
(usually promoted)
|Date 25.06.2010
Noble metal vs cheaper transition metal
› Noble metal: high activity, easy maintenance, very high price
› “cheaper” transition metal: lower activity, prone to deactivation, cheap
25
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
1998 2000 2002 2004 2006 2008 2010
year
US
$/tr
oy
ou
nce
Ru
Rh
Pd
Ni
www.kitco.com
|Date 25.06.2010
Van Krevelen: comparison of activity
26
Pine oil
PdPt/ZrO2Pt/ZrO2
NiCu/C
NiCu/CeO2-ZrO2
cracking (NiCu/d-Al2O3)
crack+NiCu/CeO2-ZrO2
NiCu/CeO2
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7
ato
mic
O/C
atomic H/C
Pine oilRu/ C 5wt%Ru/ C 3.33wt%Ru/ C 2wt%+actPd/ CPdPt/ SiO2-Al2O3 (Albe)Rh/ CeO2Rh/ ZrO2 Rh/ CoSiO3Rh/ ZrO2 RhPd/ ZrO2RhPt/ ZrO2 Pd/ ZrO2PdPt/ ZrO2Pt/ ZrO2NiCu/ Al2O3FeCu/ Al2O3NiCu/ ZrO2NiCu/ CeO2(co)NiCu/ CeO2(wet)NiCu/ CNiCu/ CeO2-ZrO2cracking (NiCu/ d-Al2O3)crack+NiCu/ CeO2-ZrO2NiCu/ sibuniteNiCu/ CeO2
Noble metal cat (TKK/BIC), not flowable NiCu, Albe3, flowable
commercial noble metal catalyts, very low viscosity
Ru/C Pd/C
|Date 25.06.2010
Potential catalyst: NiCu› δ-Al2O3 as support (better stability than γ-Al2O3)
› Various Ni/Cu ratio
27
Catalystc Ni (wt%)
Cu (wt%)
ABET
(m2/g)
24.5Cu 24.5 - 123
5.92Ni18.2Cu 5.92 18.2 118
13.3Ni11.8Cu 13.3 11.8 86
13.8Ni6.83Cu 13.8 6.83 122
16Ni2Cu 16 2 92
20.8Ni 20.8 - 118
|Date 25.06.201028
Hydrogenation activities› Van Krevelen plot is used to calculate the hydrogenation
activities, blank experiment as the reference
16Ni2Cu
PO
20.8Ni13.8Ni 6.83Cu
13.3Ni 11.8Cu
5.92Ni 16.82Cu24.5Cublank
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6
atomic H/C (dry)
atom
ic O
/C (d
ry)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
20.8Ni 16Ni2Cu 13.8Ni6.83Cu
13.3Ni11.8Cu
5.92Ni16.82Cu
24.5Cu
catalyst
hydr
ogen
atio
n ac
tivity
(g-1
)
16Ni2Cu and 13.8Ni6.83Cu are the most active
|Date 25.06.2010
Why is Cu needed?› Ni is a catalyst for CNT (carbon nanotube)
formation produces “carbon whiskers”, decrease the activity
› CNT formation is structure sensitive needs adjacent active sites
› Cu makes NixCu1-x alloy, and reduce the crystallite size the carbon formation is reduced
› Cu also helps the reduction
29
|Date 25.06.201030
XRD analysis
13.8Ni6.83Cu
20.8Ni
NiO
Ni
• No Ni(0) was found at 20.8Ni after reduction at 300 oC (reduction temperature of Ni is > 500 oC)
•Ni(0) was formed on 13.8Ni6.83Cu after reduction
Cu does not have HDO activity, but supports the reduction of Ni
Reduction was performed at 300 oC and 10 bar of H2
|Date 25.06.201031
What about the stability?HRTEM
Active metal particle size: 10 nm (fresh) 100 nm (spent).ICP showed leaching of Ni, Cu, and Al
Fresh 16.8Ni6.83Cu Spent 16.8Ni6.83Cu
Dissolution and recrystallisation of NiCu seem to occur
|Date 25.06.2010
Next? Find other supports …› Carbon, ZrO2, TiO2, etc
› Ongoing research
0.0 0.5 1.0 1.5 2.00
50
100
150
200
NiCu/ rice husk
NiCu/ ZrO2
NiCu/ CeO2-ZrO
2
NiCu/ TiO2
NiCu/ sibunite
non-catalytic
H2 c
onsu
mpt
ion
(NL/
kg f
eed)
Activity based on van Krevelen plot (g active metal -1)
|Date 25.06.2010
Summary on catalyst selection› A good support selection is a good start› Noble metal vs “cheaper” transition metal› Bimetallic catalyst: effect of composition
33
Heterogeneous catalysts, SϋdChemie
|Date 25.06.201034
Acknowledgement:Robbie Venderbosch, Vadim Yakovlev, Sofia Khromova, Jelle Wildschut, Anja Oasmaa, Jelmer Westra
UICUIC
Boreskov Institute of Catalysis – SB RAS