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Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Fabrizio Scala
Dipartimento di Ingegneria Chimica, dei Materiali
e della Produzione Industriale
Università degli Studi di Napoli Federico II
Napoli (Italy)
RECENT CO2 CAPTURE
TECHNOLOGIES INVOLVING
FLUIDIZED BED REACTORS
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Fossil Fuel Energy Grand Challenges
Efficiency
CCS
Low Carbon Technology
World energy-related CO2 emissions abatement in the 450 Scenario relative to the New Policies Scenario.
New Policies Scenario
450 Scenario
Toward
In the medium term Fossil Fuels will remain the main energy source Conventional fuels must be used in unconventional ways
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
CARBON CAPTURE AND SEQUESTRATION
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
CARBON CAPTURE
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
PRE-COMBUSTION CARBON CAPTURE
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
SORPTION-ENHANCED GASIFICATION
CHxOy + (1-y)H2O → CO + (0.5x + 1- y)H2
CO + H2O CO2 + H2
CaCO3 CaO + CO2
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Sorption enhanced gasification – process configuration
a) pre-gasification in a first reactor
followed by CO2 capture in a (dual
fluidized bed) reformer/regenerator
b) simultaneous gasification, reforming
and CO2 capture in a (dual fluidized bed)
gasifier/regenerator
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Calcium carbonate decomposition equilibrium curve
Calcination Carbonation
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
100 kW dual fluidized bed
gasification bench scale rig
8 MW combined heat and
power plant in Güssing,
Austria
Examples of sorption-enhanced gasification test plants
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Results of sorption-enhanced gasification tests
Product gas composition:
standard gasification vs. SEG
Gasification temperature vs.
gas composition for SEG
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Pros and cons of sorption-enhanced gasification
High reactivity fuels (biomass) are needed due to the low gasification temperature;
High hydrogen concentrations in the syngas have been demonstrated;
Limestone is one of the cheapest industrial chemicals and it is environmentally benign;
Inherent H2S capture to low ppm levels by CaO;
Deactivation of limestone by high-temperature sintering and reaction with H2S, but possibility to reactivate the material by water/steam hydration (under study);
Particle attrition is a major challenge, but can be resolved;
Carbon conversion efficiencies should be enhanced through optimization of reactor design and fluid-dynamics.
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
POST-COMBUSTION CARBON CAPTURE
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
CALCIUM LOOPING
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Calcium Looping – process configuration
Indirect heating
Direct heating
Three-reactor
configuration
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Examples of Calcium Looping test plants
10 kW experimental test facility
at IFK-U Stuttgart
1.7 MW La Pereda pilot plant
located in Spain
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
0.6
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12:00:00 13:20:00 14:40:00 16:00:00
CO
2 C
aptu
re e
ffic
ien
cy
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Car
bo
nat
or
tem
per
atu
re (
ºC)
Results of Calcium Looping tests
Example of experimental results
obtained from the 1.7 MW test
facility at la Pereda
Typical decay curves of the
CO2 carrying capacity of
different CaO particles
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Pros and cons of Calcium Looping
It is possible to easily retrofit existing boilers;
Limestone is one of the cheapest industrial chemicals and it is environmentally benign;
Another big advantage of CaO/CaCO3 is that both processes are hot enough to raise steam, i.e., both carbonator and calciner can serve as boilers;
Higher efficiency than low-temperature processes like amine scrubbing;
Inherent SO2 capture to low ppm levels by CaO;
Deactivation of limestone by high-temperature sintering and reaction with SO2, but possibility to reactivate the material by water/steam hydration (under study);
Particle attrition is a major challenge, but can be resolved;
Uses a high‐temperature oxy‐fuel regeneration cycle.
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
OXY-FUEL COMBUSTION
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
OXY-FUEL COMBUSTION
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Examples of Oxy-fuel CFB test plants
75 kW CanmetENERGY's
Minibed Oxy-fired CFBC
30 MW Flexi-Burn® CFB
Power Plant at CIUDEN,
Spain (Foster Wheeler)
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Results of Oxy-fuel CFB tests
0
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50 60 70 80 90 100Time, min.
CO
2 c
on
cen
trati
on
, %
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Avg
. b
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tem
p.,
°C
Transition from air firing to oxy-
fuel firing in CanmetENERGY’s
mini-CFBC
Tests on Oxy-fired Combustion in
CanmetENERGY’s 0.8 MW CFBC
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Pros and cons of oxy-fuel combustion
Possibility either to retrofit existing CFB boilers (mimicking actual air operation – 30% O2) or to build new plants (with smaller furnace size at high O2 concentration);
Flue gas volume after recycling is 80% smaller than conventional combustion, and its density is increased;
Moderation of temperature by the bed material in oxy-CFB boilers is an advantage compared to oxy-PC;
Similar combustion behavior than in air operation, limited influence of gasification reactions;
Species present in flue gases are in higher concentrations after oxy-fuel combustion, but effective capture is feasible;
SO2 capture in-situ by direct sulfation of limestone;
An external heat exchanger might be needed to compensate for reduced heat transfer surface;
Air separation is expensive.
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
CHEMICAL LOOPING COMBUSTION
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
1222 22 xyxymn OMmnOmHnCOOMmnHC
Fuel reactor
xyxy OMmnOm
nOMmn
2
22 21
Air reactor
CHEMICAL LOOPING COMBUSTION
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
POSSIBLE OXYGEN CARRIERS
Fe2O3/Fe3O4 Mn3O4/MnO CuO/Cu NiO/Ni CoO/Co
Temperature, °C 800 1000 800 1000 800 1000 800 1000 800 1000
CO conversion 1.0000 1.0000 1.0000 0.9999 1.0000 1.0000 0.9949 0.9883 0.9691 0.9299
Maximum CO conversion to CO2 at equilibrium
Fe2O3/Fe3O4 Mn3O4/MnO CuO/Cu NiO/Ni comments
R0 0.03 0.07 0.20 0.21 Oxygen ratio
Reactivity towards methane ← decreasing increasing →
Cost ← decreasing increasing →
Health, safety & environm. risks ← decreasing risk
Thermodynamics
<99.5% conv. for NiO
Reaction enthalpy w. CH4
CuO exothermic w. CH4
Melting point 1085°C for Cu
CLOU CuO/Cu2O
Qualitative estimation of pros and cons for the oxides
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Examples of Chemical Looping Combustion test plants
Chalmers’ 100 kW solid fuel
chemical looping combustor
TUV chemical looping
combustor G-volution System
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Results of Chemical Looping Combustion tests
Available data from full fuel and
pure char conversion during CLC
tests
CO2 capture efficiency (ηOO) and
oxygen demand (ΩOD) during a
CLC test of bituminous coal
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Pros and cons of Chemical Looping Combustion
This is the less mature technology, proof of concept achieved, but large scale operational results are missing;
It is not possible to retrofit existing boilers;
CLC is attractive and promising option for CO2 capture-ready combustion of gaseous/solid fuels, featuring inherent air separation with low energy penalty;
Extensive testing of oxygen carriers has been carried out. Conflicting trends of key carrier properties: reactivity/resistance to wear/cost. Optimal carrier to be assessed;
CLC of solid fuels still at preliminary stage. Poor contact between carrier and solid fuel. Alternative schemes have been devised, all to be assessed;
Larger installation costs.
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Oxy-fuel FB combustion is almost ready for commercialization;
Calcium Looping and Sorption-enhanced gasification are relatively mature technologies, but sorbent deactivation problems should be solved or mitigated;
For Sorption-enhanced gasification carbon conversion should be increased;
Chemical Looping Combustion is the less mature technology, offering larger potential savings in energy penalty, but it has to be demonstrated at large scale with solid fuels;
Implementation of all these techniques need the full-scale demonstration of carbon sequestration techniques.
FINAL REMARKS
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
F. Scala (Editor)
Fluidized bed technologies for near-zero emission combustion and
gasification
Woodhead Publishing Series in Energy No. 59, Cambridge, UK, 2013
ISBN: 978-0-85709-541-1 (Print) 978-0-85709-880-1 (Online)
DOI: 10.1533/9780857098801
Energy and Environment Conference, 9-10 September 2015, Rožnov, Czech Republic
Thank you for your kind
attention!