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V. Spallina, B. Marinello, M.C. Romano, F.
Gallucci, M. van Sint Annaland
Chemical Looping Reforming with Packed Bed
Technology: Experimental Study and Modelling
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
2
OUTLINE
Motivation of the study
Description of the concept
Experimental study
Conclusions
Future works
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
3
Chemical Looping Reforming has been studied only using
interconnected Circulating Fluidized Beds but H2 production (as well as
CH3OH) is more convenient (techno-economic) at high pressure
→ Packed Bed Reactor
Fuel-to-chemicals conversion is less demanding in terms of heat
management than fuel-to-heat: the overall heat of reaction is lower
when compared to fuel combustion
→ CLR vs CLC
O2 (from ASU) and H2O (from steam turbine extraction) are not for free
→ auto-thermal reforming using oxygen carrier
CCUS applied to chemical industry
→ CO2 capture convenient without subsides (e.g. carbon tax)
Exploiting chemical looping technology in other industrially relevant
processes
→ chemical looping convenient without CO2 capture policies
Motivation of the study
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
4
the main concept
Air
N2
PSA offgas
CO2+H2O
CH4 (+H2O)
Reformed syngas
OX
IDA
TIO
N
RED
UC
TIO
N
REF
OR
MIN
G
Me (i.e. Ni)
MeO (i.e. NiO)
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
5
the concept for H2 production
OX
IDAT
ION
RED
UC
TIO
N
REF
OR
MIN
G
HT-WGS PSA
PSA offgas (CH4 2.5%, CO 13.7%, H2 28.3%, CO2 55.5%)
CO2 + H2O
H2
gas turbine
Air N2
steam
steam
ηref= 75.4% HR=3.04-3.14 Gcal/kNm3
H2
EE= 30-40 kWh/kgH2
deS HP-pure CO2 to CPU
H2O
H2O natural
gas
SH steam at (500˚C, 100 bar)
Export steam (180˚C, 6 bar)
Reformate (39.4%H2, 29%H2O, 19.2%,
CO, 11% CO2, 1.1% CH4)
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
6
units FTR-SMR FTR-SMR CLR-PBR
CO2 capture NO MDEA H2O cond
reforming efficiency (LHV basis) % 74 69 75.4
Heat Rate (no steam export) Gcalfuel/kNm3
H2 3.45 3.71 3.43-3.55
Heat Rate (with steam) Gcal/kNm3
H2 3.21 3.69 3.04-3.14
Electricity (prod/cons) GWh/kgH2 0.3 -10 30-41.8
Advantages: The system is convenient also when CO2 capture is considered Compared to FTR-SMR there are less conversion/separation steps Steam to process is significantly lower: S/C for FTR is 3.4; in this process is 1.9 (comb. ATR/FTR)
Conventional turbomachines are considered
The technology is flexible to different applications (i.e. Methanol, Fischer-Tropsch, etc..)
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
1D adiabatic axially dispersed packed bed reactor model: details are in
Spallina (2013, 2015), Gallucci (2015), Hamers (2013, 2014)
The reactor model has been validated for CLC using Cu, Ni, Fe and Mn
oxygen carriers
The model has been used for design and optimization of dynamically operated
PBR
Pseudo-homogeneous model
Radial temperature or concentration gradients are neglected
Heat losses through the reactor wall are neglected (not true for lab-scale
experimental validation)
Kinetics of Ni/CaAl2O4 G-S reactions and heterogeneous reactions are based
on Medrano(2015)
7
the model
1. Spallina V, Gallucci F, Romano MC, Chiesa P, Lozza G, van Sint Annaland M. Investigation of heat management for CLC of syngas in packed bed reactors. Chem Eng J 2013;225:174–191.
2. Hamers HP, Gallucci F, Cobden PD, Kimball E, van Sint Annaland M. A novel reactor configuration for packed bed chemical-looping combustion of syngas. Int J Greenh Gas Control 2013;16:1–12.
3. Gallucci F, Hamers HP, van Zanten M, van Sint Annaland M, Experimental demonstration of chemical-looping combustion of syngas in packed bed reactors with ilmenite, Chem Eng J 2015;274:156–168
4. Medrano JA, Hamers HP, Williams G, van Sint Annaland M, Gallucci F, NiO/CaAl2O4 as active oxygen carrier for low temperature chemical looping applications, accepted for publication (Applied Energy)
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
8
the model
REDUCTION REFORMING OXIDATION
Air
N2
PSA offgas
CO2+H2O
(CH4, H2O: S/C 2)
Reformed syngas
OX
IDA
TIO
N
RED
UC
TIO
N
REF
OR
MIN
G
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
700
750
800
850
900
950
1000
1050
0 30 60 90 120 150 180 210
gas f
racti
on
[v
ol.]
Tem
pera
ture
[°C
]
time cycle [s]
CO2
CH4
H2
CO
H2O
Temperature
H2O
Reduction with PSA off-gas leads to full gas conversion
and the gas is delivered at high temperature
The reforming step is providing H2-rich gas at the
equilibrium conditions. Due to the lower temperature, the
CH4 conversion decreases at the end of reforming.
During Oxidation the Gas temperature is in the range of
770-800˚C
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
9
the model
Air
N2
PSA offgas
CO2+H2O
(CH4, H2O: S/C 2)
Reformed syngas
OX
IDA
TIO
N
RED
UC
TIO
N
REF
OR
MIN
G
The OXIDATION step heats up the bed (850-900˚C) The REDUCTION with PSA-offgas moves the heat front
to the reactor outlet (cooling less than 30% of the bed) The REFORMING acts as heat removal:
the heat front cools down the reactor ‘from left to right’
the reaction front cools down the reactor ‘from top to down’
Reactor Inlet Reactor Outlet
550
600
650
700
750
800
850
900
950
1000
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2
Te
mp
era
ture
[°C
]
reactor length [m]
Solid Temperature Profile
After OX
After RED After REF
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
10
the experiments
small size PBR (heated) (about 500 g of OC/catalyst) 10-20 L/min flow rate (1 bar up to 1100˚C)
medium size PBR (semi-adiabatic) (about 5 kg of OC/catalyst)
50-160 L/min flow rate (7 bar up to 1100˚C)
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
11
the experiments
small size PBR (heated) 10 L/min flow rate (1 bar up to 1100 ˚C)
Insulation material
Vent
Mass spectrometerH2O
AirN2
H2
COCO2
Steam
oven oven oven
Packed bed reactor
PCWater condenser
T
48
T
1
p p
Reactor Length 0.5 m Ni-CaAl2O4 as catalyst/oxygen carrier
REACTIONS: RED: H2 + NiO → H2O + Ni (ΔHR = -15 kJ/moli) CO + NiO → CO2 + Ni (ΔHR = -47 kJ/moli) CH4 + 4NiO → 2H2O + CO2 + 4Ni (ΔHR = 134 kJ/moli) REF: CH4 + H2O ↔ CO + 3H2 ΔHR = 206 kJ/moli)
CH4 + CO2 ↔ 2CO + 3H2 ΔHR = 247 kJ/moli)
CO + H2O ↔ CO2 + H2 ΔHR = -41 kJ/moli)
OX: ½ O2 + Ni → NiO (ΔHR = -468 kJ/moli)
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
REDUCTION
12
The experiments
The stability of the OC has been tested for more than 200h of operation by checking the breakthrough of the H2 using 10 l/min (20 H2 / 20 H2O / 60 N2)
0
0.05
0.1
0.15
0.2
0.25
0.3
0:00:00 0:04:19 0:08:38 0:12:58 0:17:17 0:21:36
H2 m
ol f
ract
ion
, dry
time [ hh:mm:ss]
H2 breakthrough
H2_red#1 H2_ref#1
H2_ref#2 H2_ref#3
H2_ref#4 H2_aug24th
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0:00:00 0:01:44 0:03:27 0:05:11 0:06:55 0:08:38
gas
mo
l fra
ctio
n, d
ry
time [hh:mm:ss]
syngas breakthrough 10L/min (H2/H2O/CO2/N2 20/10/20/50)
CO2
H2
CO
Different breakthroughs occur in presence of syngas
(H2/CO2/H2O 20/20/10) Reverse WGS after the OC reduction
has been completed
1st test (OC not completely activated)
Reverse WGS
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
REFORMING
13
The experiments
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0:00:00 0:00:43 0:01:26 0:02:10 0:02:53 0:03:36 0:04:19
Re
form
ate
mo
l fra
ctio
n, d
ry
time [hh:mm:ss]
Reformate composition 10 L/min (CH4/CO2/N2 10/60/30)
CO2
H2
CO
CH4
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0:00:00 0:01:26 0:02:53 0:04:19 0:05:46 0:07:12
Re
form
ate
mo
l fra
ctio
n, d
ry
time [ hh:mm:ss]
Reformate composition 10 L/min CH4/H2O/N2 10/50/40)
CO2
H2
CO CH4
Different industrially relevant compositions (combination of CH4/H2O/CO2) diluted with N2 have been tested
The experiments have been done at 900˚C, the same tests will be carried at 800˚C
The CH4 full conversion has been achieved in both cases (working with high H2O or CO2 dilution)
The methane reforming (both steam and dry) reduces the temperature → carbon deposition control has to be taken into account
Steam Reforming
Dry Reforming
300
400
500
600
700
800
900
1000
0 0.1 0.2 0.3 0.4 0.5
T [°
C]
Reactor length [m[
Bed Temperature profile (Reforming)
REF_start REF 33%
REF 66% REF_end
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
OXIDATION
14
Experiments and Preliminary validation
0.00
0.05
0.10
0.15
0.20
0.25
0:00:00 0:01:26 0:02:53 0:04:19 0:05:46 0:07:12 0:08:38 0:10:05 0:11:31
O2 v
ol.
fra
ctio
n [
%]
cycle time [hh:mm:ss]
experiment model
the temperature rise is almost 600˚C) very close to the adiabatic value (≈700˚C) The thermal model is not able to catch the temperature rise at the beginning of the reactor (heat losses model need to be refined and adjusted)
the kinetic model is predicting the breakthrough of the oxygen with high accuracy → results confirms the previous experiments by Kooiman et al. (2015) using the same OC and reactor
300
400
500
600
700
800
900
1000
0 0.1 0.2 0.3 0.4 0.5
Tem
pe
ratu
re [
°C]
reactor length [m]
exp_30s exp_60s exp_90s
model_30s model_60s model_90s
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
Chemical Looping Reforming is a very promising way to combine H2 production and CO2 capture
A preliminary assessment shows already the gain (+1.5 percentage points compared to benchmark technologies)
Several industrial relevant processes can benefit from chemical looping
Commercial Ni-based OC has been (is being) successfully tested in a lab-scale reactor (more than 200 h)
The first lab tests confirm the proof-of-principle (at 900˚C and 1 bar for 10 L/min of syngas using different composition)
Carbon deposition play an important role due to the temperature variation (high syngas dilution)
Reformate composition is different than conventional plant (is that a problem in case of plant retrofitting?)
15
Conclusions
…but the way is long →
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
Experiments
Mapping the operating conditions of the reactors: composition,
temperature, dilution (i.e. S/C), flow rate
Oxygen carrier characterization and stability test (under multiple cycles)
Scale-up from 10 L/min (small PBR) to 100 L/min and 5 bar @TU/e
16
Future research
Modelling
Design of the reactor
Investigation with different reactor concepts
Heat transfer modelling (i.e. heat losses, etc…)
Heat management strategies
Techno-economic assessment of full scale plant and comparison with
conventional technologies for H2 production
Techno-economic assessment of the system for different process
(CH3OH, Fischer-Tropsch, etc..)
Chemical Looping Reforming with Packed Bed Technology: Experimental Study and Modelling
17
THANK YOU FOR YOUR ATTENTION!
CONTACT INFO: Vincenzo Spallina
mail: [email protected]