17-19 may 2011, abu dhabi results from test campaigns at the 1 … · 2013. 7. 25. · esbjerg 1t/h...
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Results from test campaigns at the 1 t/h CO2 PCC pilot plant in Esbjerg under the EU FP7 CESAR project
Jacob Nygaard Knudsen, Jimmy Andersen, Jørgen N. Jensen – DONG Energy
Ole Biede – Vattenfall
IEAGHG - 1st Post Combustion Capture Conference
17-19 May 2011, Abu Dhabi
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CESAR Project Consortium
R&DIFP (FR)TNO (NL)SINTEF (NO)NTNU (NO)POLYMEN (FR)CNRS (FR)U. KAISERSLAUTERN (DE)
Oil & GasSTATOILHYDRO (NO)GDF (FR)
Power CompaniesDONG Energy (DK)VATTENFALL (SE/DK)E.ON (DE/UK)ELECTRABEL (BE)RWE (DE/UK)PPC (GR)POWERGEN (UK)
ManufacturersALSTOM POWER (SE)DOOSAN BABCOCK (UK)SIEMENS (DE)BASF (DE)
Coordinator: TNO
CESAR: CO2 Enhanced Separation And Recovery
3-year EC sponsored project (2008 – 2011) in the 7th Framework Programme
Aim: To reduce the cost of CO2 post-combustion capture
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Objectives with Pilot Plant Testing in CESAR
Evaluate the potential of reducing the energy consumption of CO2 capture through advanced absorption/desorption process configurations in pilot-scale
Evaluate the potential of reducing the regeneration energy through use of novel amine solvents
Determine the performance of a benchmark solvent (MEA) and two novel solvents at realistic operation conditions for future full-scale application in coal-fired power plants
Monitor actual solvent degradation, losses and by-products, corrosion and emissions for benchmark and novel solvents
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Esbjerg 1t/h CO2 Capture Pilot Plant
Esbjerg Pilot Plant details
Located at a coal-fired power station in Esbjerg, Denmark
Erected and commissioned in 2005 (CASTOR)
Operates on a slip stream of flue gas taken directly after the wet FGD
Flue gas flow: 5000 Nm3/h (0.5% of 400 MWe)
CO2 capture capacity: 1000 kg/h
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Flue gas from power plant
Mechanical filters
Lean MEA
Rich MEA
Steam
Treated flue gas
CO2 Out
Cooling water circuit
Reboiler
MEA/MEA heat exchangerABSORBER STRIPPER
Condensate
Wash section
Esbjerg Pilot Plant Flow Diagram
Revamping of absorber with structured packing
Expansion of cross flow heat exchanger
Absorber inter-cooling
Installation of vapour recompression
Fresh water
Bubble cap polisher
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CESAR Test Programme at Esbjerg Pilot Plant
The selected pilot plant modifications were installed during 2008. Afterwards, three test campaigns were conducted:
Benchmark solvent: >1000 hours with ”30%-wt. MEA” (Mar 2009 – July 2009)
1st novel solvent: >1000 hours with blend of AMP & piperazine (PZ) ”CESAR 1”
(Nov 2009 – Feb 2010)
2nd novel solvent: • 200 hours with 30%-wt. ethylenediamine (EDA) ”CESAR 2”
(Mar 2010 – Jun 2010)
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Detailed Outline of Test Campaigns
Parameter variation tests:
500 hours of continuous operation
Miscellaneous tests
1A) Optimisation of solvent flow rate (at 90% capture)1B) Optimisation of inter-cooler temperature (at 90% capture)1C) Optimisation of flash pressure (at 90% capture)2) Variation of reboiler steam input at optimum solvent flow3) Variation of stripper pressure (at 90% capture)
- Operation at ”optimised” conditions- Achieving 90% CO2 capture (on average)- Quantification of solvent consumption and degradation- Characterisation of corrosion behaviour
- Emission measurements!- Absorber pressure drop measurements- Load following capability and transient tests
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Revamping of AbsorberD
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Absorber packing changed from IMTP50 random packing to Mellapak 2X structured packing
New liquid distributors
Installation of bubble cap tray on top of wash section
Results:
Absorber • P decreased from • 600 to • 300 mm H2O at 5000 Nm3/h (includes • P of 20-40 mm H2O new bubble cap tray)
No significant impact on mass transfer with MEA
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Improved Rich/Lean Heat ExchangerD
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New Rich/lean heat exchanger with increased
capacity installed
Heat transfer area increased with 35%
Results:
• T (pinch side) decreased from 7.1-8.0 to 4.0-
4.3oC depending on L/G which is equal to • 0.2-
0.3 GJ/ton CO2 more sensible heat being
recovered
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Optimisation of Absorber L/G with Improved Rich/Lean HX
30% MEA benchmark, stripper pressure 0.85 barg, flue gas flow • 5000 Nm3/h and • 90 % CO2 recovery
∆T = 4.0-4.3ºC
50
60
70
80
90
100
3,0
3,2
3,4
3,6
3,8
4,0
2,0 2,5 3,0 3,5 4,0
CO
2re
cove
ry (
%)
Ste
am c
on
sum
ptio
n (G
J/to
n C
O2)
Absorber L/G ratio (kg/kg)
Steam consump. CO2 recovery
CASTOR: ∆T = 7.1-8.0ºC
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Single Stage Absorber Inter-coolingD
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Inter-cooler installed between first and second
bed from the bottom
Solvent may be cooled down to • 25oC
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Effect of Absorber Inter-cooling
30% MEA benchmark, Flue gas flow • 5000 Nm3/h, L/G • 3 kg/kg, Stripper pressure =0,85 barg, CO2 capture • 90%
Solvent 40ºCFlue gas 48ºC
50
60
70
80
90
100
3,0
3,2
3,4
3,6
3,8
4,0
20 30 40 50 60
CO
2re
cove
ry (
%)
Ste
am c
on
sum
ptio
n (G
J/to
n C
O2)
Inter-cooler temperature (oC)
Steam consump. CO2 capture
25
35
45
55
65
75
0 4 8 12 16 20
Ab
s. te
mp
erat
ure
(oC
)
Packing height (m)
58,1 45,0 37,5 30,0 24,9
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Lean Vapour RecompressionD
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Hot lean solvent from the stripper is flashed
The vapours are compressed by a mechanical
compressor and injected in the stripper bottom
The liquid phase from the flash enters the
rich/lean heat exchanger
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Effect of Lean Vapour Recompression
Flue gas flow: 5000 Nm3/h, Solvent flow 18 m3/h, Stripper pressure (top): 0.85 barg
0
10
20
30
40
50
2,6
2,8
3,0
3,2
3,4
3,6
3,8
4,0
0,0 0,2 0,4 0,6 0,8 1,0
Incr
ease
d p
ow
er c
on
sum
p. (
kWh
/ton
CO
2)
Ste
am c
on
sum
ptio
n (G
J/to
n C
O2)
Flash pressure (barg)
Steam Power Isentropic Power
Steam consumption reduced significantly....But increased electricity consumption!!!
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Test Campaigns with Novel Solvents
Two novel solvent systems was developed in the CESAR project and brought to testing in Esbjerg:
CESAR 1: 3 M AMP + 2 M PZ
CESAR 2: 5 M EDA
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Comparison of Regeneration Energies
Flue gas flow = 5000 Nm3/h, Pstripper = 1.85 bara, CO2 • capture 90%, No inter-cooling, No LVC
3,0
3,2
3,4
3,6
3,8
4,0
1,0 1,5 2,0 2,5 3,0 3,5 4,0
Ste
am c
on
sum
ptio
n (G
J/to
n C
O2)
L/G (kg/kg)
MEA CESAR 1 CESAR 2
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Comparison of Solvents – Influence of Inter-Cooling
2,7
2,9
3,1
3,3
3,5
3,7
20 30 40 50 60
Stea
m c
onsu
mpt
ion
(GJ/
ton
CO
2)
Inter-cooler temperature (oC)
MEA CESAR 1 CESAR 2
Saving • 0.2 GJ/ton or 7%
Saving • 0.1 GJ/ton or 3%
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Comparison of Solvents – Influence of Vapour Recompression (1)
2,6
2,8
3,0
3,2
3,4
3,6
3,8
0,0 0,2 0,4 0,6 0,8 1,0
Ste
am c
on
sum
ptio
n (G
J/to
n C
O2)
Flash pressure (barg)
MEA CESAR 1 CESAR 2
0.7 GJ/ton or 20% reduction
0.4 GJ/ton or 13% reduction
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Comparison of tests – Influence of Vapour Recompression (2)
0
10
20
30
40
0,0 0,2 0,4 0,6 0,8 1,0
Po
wer
co
nsu
mpt
ion
(kW
h/to
n C
O2)
Flash pressure (barg)
MEA CESAR 1 CESAR 2
0
5
10
15
20
25
0,0 0,2 0,4 0,6 0,8
Sav
ing
((kW
ste
am/ k
W p
ow
er)
Flash pressure (barg)
MEA CESAR 1 CESAR 2
Reported values are actual power consumptions. The power consumption may be reduced by use of more efficient compressors
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Summary of Improvements with MEA, CESAR 1 and CESAR 2
Conditions: Flue gas flow 5000 Nm3/h, Optimal L/G, CO2 removal • 90% , Stripper pressure 1.85 bara
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
Standard Improved Hx Improved Hx+IC Improved Hx+LVR Improved Hx+IC+LVR
Spec
ific
stea
m c
onsu
mpt
ion
(GJ/
ton
CO2)
MEA CESAR 1 CESAR 2
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It is not just Energy Consumption...
Other aspects than energy consumption are important when considering new amine solvents:
•Corrosion issues/material selection
•Solvent consumption and degradation
•Operating/Handling issues
•Environmental impact
•......
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Corrosion Issues – Build-up of Iron in Solvent
0
1
10
100
1000
0 200 400 600 800 1000 1200
Fe c
onte
nt o
f sol
vent
(mg/
l)
Operating hours (full load hrs.)
MEA CESAR 1 CESAR 2
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Comparison of Solvent Consumptions
Main sources of solvent loss:
MEA : Loss mainly due to degradation
CESAR 1: Loss mainly due to emission (AMP) and absorption of SO2
Solvent AmountMEA* : 2.3 kg/ton CO2
CESAR 1: AMP 0.73 kg/ton CO2
PZ 0.15 kg/ton CO2
CESAR 2: Seemingly low, not quantified!
Consumption numbers based on 500 hours continuous testing
*Previously measured MEA losses: 1.4-2.4 kg/ton CO2
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Comparison of build-up of Heat Stable Salts (Degradation)
0
0,2
0,4
0,6
0,8
1
1,2
0 200 400 600 800 1000 1200
Hea
t sta
ble
salt
s (%
-wt)
Operating hours (full load eqv. hrs.)
CESAR 1 MEA
CESAR 1: • 80% of HSS formation due to absorption of SO2 and HCl!
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Emission Measurements at Esbjerg
Pioneering work regarding emission characterisation has been conducted at Esbjerg as part of the CESAR project:
Challenge: No standard sampling methods for amines and (most) amine degradation products in flue gas streams (high moisture content)
Iso-kinetic sampling of flue gas at inlet and outlet from CO2 absorber
Quantification of emissions of various inorganic and organic species
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Determination of Inorganic Emissions
Emission results using MEA
Compound Unit Inlet Outlet CO2 mg/Nm3 13.2 1.7 CO mg/Nm3 9.8 12.4 HCl mg/Nm3 0.06 < 0.04 HF mg/Nm3 < 0.04 < 0.04 SO2 mg/Nm3 14.4 1.5 NOx mg/Nm3 27.5 34.4 TOC mg/Nm3 < 2 < 2 Particulate mg/Nm3 2.1 < 1.2 Al µg/Nm3 75 < 2 Ca µg/Nm3 88 < 1 Fe µg/Nm3 49 < 1 Si µg/Nm3 140 < 8
Pilot plant operated at steady state
conditions with bubble cap polisher
Flue gas outlet temperature • 50oC
Measurements based on 2-hours
sampling periods
Both CEMs and wet chemical methods
are applied
Indicates that emissions of coal fly ash are significantly reduced!!
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Determination of Organic Emissions
Pilot plant operated at steady state
conditions with and without bubble cap
polisher
Flue gas outlet temperature • 50oC
Measurements based on 2 x 1-hours
sampling periods
Emission results under MEA operation (mg/Nm3)
Abs. inlet Abs. outlet Compound - No polisher polisher Formaldehyde < 0.1 0.7 < 0.1 Acetaldehyde 0.2 1.1 0.8 Acetamide < 0.6 < 1.0 < 1.0 MEA < 0.1 0.7 < 0.3 DEA < 0.2 < 0.3 < 0.2 Methylamine < 0.2 < 0.3 < 0.2 Ethylamine < 0.2 < 0.3 < 0.2 Dimetylamine < 0.2 < 0.3 < 0.2 Ethylenediamine < 0.2 < 0.3 < 0.2 NH3 < 0.1 23 20 VOC 0.7 4.1 0.5 Nitrosamines ? ? ?
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Summary Novel Solvents
CESAR 1
Good energy efficiency and high CO2 cyclic capacity
Excellent chemical stability, low corrosiveness, can be thermally reclaimed
Downsides: Volatility (AMP), nitrosamine formation (PZ), biodegradability and costs!
CESAR 2
Moderate energy efficiency and cyclic capacity (slightly better than MEA)
Good chemical stability and relatively low volatility
Downsides: EDA is very corrosive!
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Conclusions Pilot Plant Testing
A series of process upgrades have been implemented at the Esbjerg 1t/h pilot plant and test campaigns with MEA and two novel solvents have been conducted. Main findings:
Energy consumption could be reduced with up to 25% i.e. from 3.7 to 2.8 GJ/ton (CESAR 1 + Inter-cooling)
The reboiler duty of the "classical" 30% MEA process can be significantly reduced by LVR (3.6 to 2.8 GJ/ton) on account of increased auxiliary power consumption. The true benefit of LVR will be site specific
Combination of process optimisation and novel solvents leads to significant energy savings. However, the impact of process upgrades is very solvent dependent.... process design and solvent development go hand in hand!
New knowledge on emissions of potentially harmful components have been obtained, but there is still a lot to do!