HAPPIPOLTTOKONSEPTIT - OXYCONCEPTS
IV Liekkipäivä
23.1.2008, Tampere
Toni Pikkarainen & Antti Tourunen
VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Project content & partners
OXYCONCEPTS
OXYGEN
PRODUCTION
• cryogenics
• membranes
• solid adsorption
PHEOMENA
• burning
• ash formation
• materials
(corrosion, erosion)
CO2 STORAGE
• transports
• disposal
• follow-up
COMBUSTION
CO2
PROCESS
• CFB
• PC
• CLC
• grate
SEPARATION
• compression
and liquation
• solid adsorption
• liquid adsorption
CONCEPTS
• simulation
• optimization
• demonstration
plan
• competitiveness
RESEARCH INSTITUTES
PARTICIPANTS
VTT Technical Research
Centre of Finland (54%),
coordinator
Fortum
PVO
Foster Wheeler
Metso Power
VAPO
Jyväskylä Energy
TEKES
VTT
TUT
Lappeenranta University
of Technology (17%)
Helsinki University
of Technology (11%)
Tampere University
of Technology (18%)
TOTAL 1.36 M€
Project in Tekes ClimBus-programme, duration 06/2006 - 12/2008
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Goals & results
•
Main goals:
• to evaluate technically and economically different oxygen production techniques,
combustion and CO2 capture processes, and the integration of these to overall
concepts
• to create technical readiness for demonstration of oxygen combustion by using
state-of-the-art knowledge, experiments, modeling and simulation
• to create demonstration plan for oxygen combustion for an existing power
plant(s) in Finland
• to evaluate oxygen enriched combustion for power boosting of a power plant
•
Main results
• evaluation of oxygen combustion business potential for implementation in
existing and new power plants
• improvement of competitiveness of Finnish companies in energy sector by
developing CO2-free power production technologies
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Tasks
1.
Oxygen production and enrichment
•
2.
Applications of oxygen combustion
a.
b.
c.
3.
study of technical and economical aspects and potential new solutions
Concept development
•
6.
survey for state-of-the-art, creating of modeling tool and estimation of competitiveness
CO2 capture and storage
•
5.
PC and CFB boilers applications for retrofit plants (O2 content 21-28%)
PC and CFB boilers applications for ”green field” plants (O2 content 28-60%)
Oxygen enrichment for power boosting of power plant (replacing the use small peak load oil/gas burning
plants)
Chemical Looping Combustion (CLC)
•
4.
study of commercial and developing techniques, their costs and potential
optimization of the whole oxygen combustion concept, demonstration plan for selected existing power
plant(s) and competitiveness of the concept compared to other CO2 mitigation techniques
Phenomena research
•
experiments and model development of burning and emissions applied to oxygen combustion conditions
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Oxygen combustion
Air
Using of oxygen
instead of air to avoid
nitrogen diluting the
flue gas makes the
capture of CO2
favourable
N2
Air
separation
Partial CO2
circulation
Part of the flue gas (mainly CO2
and H2O) needs to circulated
back to the boiler to control the
flame temperature
CO2 is separated from the
flue gas by compression
and cooling
O2
Coal
Flue gas
cleaning
Boiler
Purification
Compression
Condensation
CO2/H2O
CO2
Steam
turbine
H 2O
G
Vent gas
Ship or pipeline trasport to
storage site in supercritical
form (p=80-150 bar, high
density & low viscosity)
Transport
Storage
4000
Temperature [°C]
3500
Adibatic combustion temperature
90
Flue gas recirculation rate
80
70
3000
60
2500
Air
combustion
50
2000
40
1500
30
Flue gas recirculation [%]
Examples of differences between air/oxyfuel combustion of bituminous coal
Feed gas composition
O2 [%-wet]
N2 [%-wet]
CO2 [%-wet]
H2O [%]
SO2 [ppm-wet]
Normalized flow
[wet gas]
Flue gas composition
Air comb.
20.83
78.36
0.00
0.81
0
Oxyfuel comb.
27.00
0.35
51.51
21.12
112
Air comb.
3.26
75.16
14.75
6.82
89
Oxyfuel comb.
2.51
0.47
68.80
28.20
149
100
72
100
21
20
1000
20
~27 30
40
50
Feed gas O2 content [%, wet]
60
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Chemical looping combustion (CLC)
Oxidation
Reduction
Images of the oxygen carrier composed of 40% Mn3O4 on 60% Mg-ZrO2
(to storage)
Air
Chemical looping combustion is a process where a direct contact between fuel and
combustion air is avoided. This is accomplished by an oxygen carrier, i.e. a metal oxide,
by which the oxygen is transferred from the combustion air to the fuel in the oxidation
reactor. Oxygen carrier is then conveyed into the reduction reactor, where it is reduced
by gaseous fuel e.g. methane. Flue gas formed is rich in CO2 and H2O, when CO2 could
be separated by means of compression and cooling.
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 1 - Oxygen production
1.4
Fuel power [MWth]
14
135
1350
150
Cryogenic distillation
Pressure swing adsorption
Ion transfer membranes
Theoretical minimum
500
Cost [€/tn O2]
Energy consumption [kWhe/tn O2]
600
400
300
200
Maintenance
3%
Labour
17 %
100
Power
27 %
Capital
53 %
50
100
0
0
0
10
100
1000
Capacity [tn O2/day]
10000
200
400
600
Capacity [tn O2/day]
• Cryogenic distillation is currently the only commercial large scale,
high purity oxygen production method
• Membrane technics are attractive because of their low specific
energy consumption and compact size, but these are still in
development stage
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800
VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 2 - Applications of oxygen combustion
• A set of CFB-pilot tests with bituminous coal
was carried out at normal air combustion and
oxygen combustion conditions
• All process values was kept as equal as
possible
Fuel power
Limestone-Ca to fuel-S ratio
Feed gas O2
Primary gas share
Bed temperature
Flue gas O2
Air combustion
Air combustion Oxygen combustion
(without limestone)
55
54
62
1.6
1.6
20.8
20.8
28.3
60
60
60
845
850
905
5.3
5.3
5.4
kW
mol/mol
% wet
%
ºC
% dry
FTIR sampling port
Gas analysator
Flue gas
recirculation
250
Bag filter
Deposit probe port
Gas cooling
Relative value [%]
Observation port
225
Air combustion (without limestone)
200
Air combustion
175
Oxygen combustion (O2=28%)
To stack
Sampling port
Secondary
cyclone
Zone 4
Primary
cyclone
Sampling port
Sampling port
FTIR sampling port
150
Zone 3
Sampling port
125
Sampling port
Zone 2
100
Sampling port
75
Fuel containers 1 and 2
50
25
Zone 1
Secondary gas
Additive
container
O2, CO2, N2
M
0
Primary gas heating
CO
NO
N2O
SO2
HCl
Sulphur
capture
All the emissions were lower at oxygen combustion mode
PC control and data logging system
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Sampling port
Air
VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 2 - Applications of oxygen combustion
•
•
Development of stationary 3D CFB-model for oxygen combustion and application of the
model in reactor process studies and optimisation
Case-study based on Lagisza CFB (460 MWe, SC OTU):
1) Air combustion (reference)
2) Oxygen combustion 1: Reduced furnace HTEX-area (O2 = 23.9 % wet)
3) Oxygen combustion 2: Original HTEX-area (O2 = 23.9 % wet)
4) Oxygen combustion 3: Original HTEX-area and reduced flue gas recirculation (O2 = 29.6 % wet)
AIR
OXY 1
OXY 2
OXY 3
Effect on combustion process and heat fluxes was small, thus CFB oxygen
combustion is feasible as retrofit (with existing boiler construction)
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 2 - Applications of oxygen combustion
PARTICLE FLOW MODEL
• A reacting particle (fuel or limestone) encounters zones with different
temperatures and different gas concentrations while travelling inside the
furnace.
• The particle history affects the reactions
(e.g. buildup of sulfate layer).
• Transient particle models are developed to calculate the reactions, mass and
heat transfer for a particle in a changing environment.
• In the 3D process model, the particle tracks are solved in Lagrangian frame
using a random walk model.
Example of process values experienced
by a particle during one particle track.
Illustrative image showing mean particle
track (red) and stochastic tracks (black)
in 3D oxygen concentration field.
For actual model, thousands of tracks are
calculated and fluctuations are larger.
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 2 - Applications of oxygen combustion
• Prosim process simulation of oxygen enriched combustion cases and reference air combustion case:
• case 1: normal 100% load air combustion = 267 MWst
• case 2: 2.5 % oxygen enrichment to sec./tert. air = +15 MW
• case 3: 5.0 % oxygen enrichment to sec./tert. air = +30 MW
• Additional power was recovered by new district heating heat exchanger installed as last heat exchanger
• Economical evaluation of oxygen enrichment was done, when the addional heat replaces the use of small (oil fired)
heating stations
• As a result, break-even point for oxygen enrichment was calculated as €/ton O2 produced basis (price includes in
addition to cost of oxygen production, costs of district heating installation and other required modifications)
Fuel costs
Tax for fossils
Subsidy for bio
CO2 charge
35
~0.9 M€ savings
~1.7 M€ savings
6.70
6.63
6.57
0.72
0.61
0.48
21.78
21.17
•
30
25
M€ / Year
20
•
15
10
22.48
¾
5
0
-5
-0.97
Case 1 (normal)
-0.97
Case 2 (+15 MW)
Savings in operating costs (without O2-production):
•
case 2: about 0.9 M€/year
•
case 3: about 1.7 M€/year
compared to reference case 1.
Break-even points for oxygen enrichment:
•
case 2: about 57.3 €/ton O2
•
case 3: about 49.5 €/ton O2
Power boosting by oxygen enrichment could be
in a certain circumstances competitive concept
-0.97
Case 3 (+30 MW)
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 3 - Chemical looping combustion
• Modeling tool development based on literature and 0D mass & heat
balance calculation → first estimation of CLC combustor design
• Laboratory scale oxygen carrier experimentals to support modeling
• "novel" Ni-based carrier materials are produced
• oxidising/reducing tests in termobalance at different conditions
Sample
holder
Microbalance
data
acquisition
He-flushing
Winch
system
Ø16mm
Expansion
valve
PRESSURISABLE
THERMOBALANCE
Pressure range 1- 90 bar
Temperature max = 1000°C
Sample
lock
Filter
Steam
condenser
air/O2/N2
CO 2
H2
CO
Reactor
data
Thermocouple/ acquisition
Pyrometer
Steam
generator
Water pump
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 5 - Concept development
• Suitability of different simulation programs - Prosim, Balas, IPSEpro and partly Aspen) - for oxygen combustion
concept development was estimated by "simulation-matrix" based on Meri-Pori -case (565 MWe PC-boiler)
• All the programs were found to be capable for simulations with their own strengths/weakness:
• Prosim and IPSEpro were better in power plant process simulations
• Balas and Aspen were better in chemical process simulations (e.g. ASU and CO2 purification/separation)
• Simulation models has been created based on two utility scale power plant chosen as concept
development/optimisation subject - Lagisza CFB 460 MWe and Meri-Pori PC 565MWe - and parameters studied
are for example:
Purity of oxygen produced (by ASU) effect on (eletricity production) efficiency,
Burning gas oxygen concentration (O2 + FGRC) effect on efficiency (see figure),
Separation degree of CO2 effect on efficiency, and
Pressure level of CO2 separation (primary compression) effect on separation efficiency, product gas purity and specific
energy consumption
Electrical efficiency as a function of O2-concentation into
the burner (Burning power 1275 MW, design case)
35
Electrical Efficiency [%]
•
•
•
•
34.5
34
33.5
33
32.5
0
20
40
60
O2-concentration into burner [%]
80
100
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Result examples:
Task 6 - Phenomena research
• Drop tube reactor tests for studying and comparing
burning at air and oxygen combustion conditions
• Pyrolysis and char combustion tests for different fuels
and particle size fractions in gas atmosphere
containing
• O 2 + N2 ,
• N2 + H2O,
• CO2 + N2 and
• CO2 + O2 + H2O
with different mixing ratios and temperatures
• submodels of combustion and emission formation will
be developed for CFD modeling of furnace
Volatile Matter %
Volatile Matter USA Coal
50
40
30
Coal 100-125 µm
20
Coal 180-200 µm
10
0
700
800
Temperature °C
900
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VTT TECHNICAL RESEARCH CENTRE OF FINLAND
Thank you
for your attention!
Addional information: Toni Pikkarainen, toni.pikkarainen@vtt.fi
Antti Tourunen, antti.tourunen@vtt.fi
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