Post on 13-Nov-2020
Institute of Thermal and Separation Processes/Heat and Mass Transfer
Li f ti f O f l Fl GDipl.‐Ing. D. KöpkeProf. Dr.‐Ing. R. Eggers
Liquefaction of Oxyfuel Flue Gas
Experimental Results andExperimental Results and Comparison with Phase Equilibrium Calculations
Institute of Energy Systemsy
Dipl.‐Ing. K. MieskeDr.‐Ing. A. Kather
1st Oxyfuel Combustion Conference
Cottbus 2009Cottbus, 2009
Overview
• Introduction
• Theoretical Background: Phase Equilibrium Calculation
• Experimental Setupp p
▸ Drop tube furnace
▸ Liquefaction plant
• Experimental results• Experimental results
▸ Composition of liquid and gaseous phase
▸ Nitrous and sulphur components
2
Introduction
• IHI JapanExperiments in Feb 2008, presented at IEA Oxy‐CombustionWorkshop in Yokohama, Japan, März 2008 (Uchida et al. Recent Test Resultson Oxy‐Fuel Combustion Using the Pilot‐Scale Test Facilities)T = ‐50°C, p = 24 bar (pmax = 45 bar), thermal capacity: 1,2 MWth
CO2‐concentration at compressor outlet: 50% • Hamburg University of Technology
First liquefaction experiment: July 2008T = ‐30 … ‐55°C, pmax = 60 barLiquefaction of 5 m3/h oxyfuel flue gas from hard coal
• Vattenfall, Schwarze PumpeOfficial beginnig of operation: August 2008Thermal capacity: 30 MWth, lignite
• TU DresdenEnd of 2008; 5…10m3/h flue gas, lignite; / g , g
3
Goal of the Experiments
• Validation of Models
▸ Aspen Plus
▸ phase equilibrium calculationsp q
▸ Heat transfer measurements
• Understanding and experience with the process
• Identification of problems• Identification of problems
4
Phase Equilibrium Calculation
gaseous phase
• Thermodynamic equilibrium calculation withequations of state:
flue gas
gaseous phasey i.e.
• Peng‐Robinson‐EOS,
• Redlich Kwong Soave EOSflue gas
T,Pz
• Redlich‐Kwong‐Soave EOS
• PSRK
•
xliquid phase
• …
liquid phase(CO2 rich)
5
Phase Equilibrium Calculation
• Phase equilibrium measurements
▸ phase equilibrium measurements in high pressure view cells
▸ Modelling with equations of stateg q
120
140
60
80
100
p in
bar
0
20
40T = 244,4 KT = 258,1 KT = 273,1 KT = 283,2 K
00,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8
molar fraction argon in mol/mol
Phase equilibria measurementCO ‐Argon
High pressure view cellCO2‐Argon, Koepke, Eggers, Chemie Ingenieur Technik 79/8, 2007
6
Phase Equilibrium Calculation
0
80
0
20 T = ‐30,5 °C
60
8020
40
equilibrium composition of gaseous phase
P = 38,4 bar
O
40
6040
60
gaseous phaseO2
N
20
4060
80theor. equilibrium composition of gaseous
h2 phase
N2
CO
0
20
0 20 40 60 80
80 pliquid phasephase region
theo. phase equil.
CO2
© Köpke, Eggers 2009
00 20 40 60 80xCO2 in mol/mol
7
Capture rate and purity
6
CO2‐purityCO2‐capture rate
4
5
96 %
95 %95 %
90 %
80 %
3
p in M
Pa 97 %
98 %
80 %
D i t li
2
p Dew point line
0
1
Oxygen purity: 99,5%Leakage air: 2%‐60 ‐40 ‐20 0
0
T in °C
Leakage air: 2%
8
Experimental Setup: Drop Tube Furnace
• Combustion capacity: 20 kW
• Heated ceramic tube:
▸ Ø150 mm, 2 m length,, g ,
▸ 5 independent segments,900 – 1600 °C
• Artificial combustion atmospheresArtificial combustion atmospheresby mixing O2, CO2, N2, steam and air
→ constant combustion conditions
• Adding of SO an NO to the feed gas• Adding of SO2 an NO to the feed gas
→ effects of Oxyfuel combustion are investigated separately
M t f iti d• Measurement of gas composition and temperature and ash analyses
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Experimental setup: Liquefaction plant
i t condenser CO ‐compressorlgas mixture
coal
condenser CO2‐compressor
condenser
cyclone
el. H2O ash
sorptive
drop tube furnace H2O
GCstack
sorptivedrying
separator
gas phase
GC
CO2‐condenserliquid phase
gas phase
© Köpke, Eggers 2009© Köpke, Eggers 2009
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Experimental results
6
CO2‐purityCO2‐capture rate
Combustion:• hard coal• Atmosphere: O2/CO2• O content 30%
4
5
96 %
95 %95 %
90 %
80 %
• O2 content: 30%• Residual O2 content: 4%• Condensation at: • T = ‐30,5 °C
3
p in M
Pa 97 %
98 %
80 %
D i t li
• P = 38,4 bar• V = ~3 Nm3/h• CO2 content in liquid phase: 95 6 mol%
2
p Dew point line
Experiments
in liquid phase: 95,6 mol%
+ Leckage air
0
1 Experiments
Oxygen purity: 99,5%Leakage air: 2%‐60 ‐40 ‐20 0
0
T in °C
Leakage air: 2%
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Experimental results
0
80
0
20 T = ‐30,5 °C
60
8020
40
theor. equilibrium composition of gaseous phase
T 30,5 CP = 38,4 bar
40
6040
60
gaseous phase
20
4060
80gaseous phase
2 phase experimental values
theor. equilibrium composition of l d h
20
0 20 40 60 80
80 p aseregion
values
theo. phase equil.
liquid phase
© Köpke, Eggers 2009
0 20 40 60 80xCO2 in mol/mol
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Experimental results
0
6
40,9bar und ‐46,4°C
80
0
20
4
5
96 %
95 %95 %
90 %
CO2‐purityCO2‐capture rate
40
6040
60
3
4
p in M
Pa
96 %
97 %
98 %
80 %
Dew point line
0
20
0 20 40 60 80
80
i l/ l
1
2
Experiments 60
8020
40
xCO2 in mol/mol
‐60 ‐40 ‐20 00
T in °C20
4060
80
13
21,9 bar, ‐46,4°C 00 20 40 60 80xCO2 in mol/mol
Experimental results
0 Combustion:
80
0
20
Combustion:•hard coal•Atmosphere: O2/CO2/H2O•O2 content (dry): 30%
40
6040
60
•Residual O2 content: 4%•Condensation at: •T = ‐46,4 °C•P = 38,4 bar
0
20
0 20 40 60 80
80
i l/ l
P 38,4 bar
pH‐values of water condensates:Ambient pressure condenser: pH 2,6
t d t f
21,9 bar, ‐46,4°C
xCO2 in mol/mol water condensate from intercoolers of the compressor: pH 0,8
Flue gas composition before condensation:CO2: 89,74%N2: 5,9%O2: 4,3%NOx: ~50 ppmNOx: 50 ppmSO2: 16 ppm
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Condensates
d COgas mixture
coal
condenser CO2‐compressor
condenser
cyclone
el. H2O ash
sorptive
condenser
drop tube furnace H2O
H2O
GCstack
sorptivedrying
separatorGC
CO2‐condenserliquid phase
gas phase
© Köpke, Eggers 2009
Reaction of SO2 to CO2, catalysed by NOx (lead chamber process) leads to very low ph‐values of the water
15
p ) y pcondensates, solid formation in the plant
Composition of condensates
• Experimental setup:
▸ P= 40bar
▸ Composition flue gas: SO42‐ NO3
‐ S
• NO3‐ and SO4
‐ concentration in water condensates
▸ O2: 6,84%
▸ CO2: 87,21
▸ NO: 0,068%
g/L mg/L g/L
Low pressure
condensate
3,2 127 2,4
▸ NO2: 0,002%
▸ SO2: 0,07%
+ leckage air ~6%
condensate
1st compression step
(3bar)
6,76 490 3,8
2nd compression step
(11bar)
114 4900 49
3rd compression step 46,6 46,6 171
Reaction of SO2 to CO2, catalysed by NOx leads to very low h l f h d lid f i i
p p
(40bar)
, ,
ph‐values of the water condensates, solid formation in the plant
Solid formation
Silcagel Solidformation in water separator
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Summary
• Liquefaction plant for oxyfuel flue gas has been built
▸ Real oxycombustion flue gas
▸ flexible and stable operationp
▸ Pmax=60bar
▸ Tmin=‐55°C
• Experiments are in good accordance to theoretical calculations• Experiments are in good accordance to theoretical calculations
• CO2 contents higher than 98% have been reached
• First results according sulphur components:
▸ Very low ph‐values in water condensates (ph<1)
▸ Solids formation and corrosion problems (sulphur and salts)
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Thank you for your interest