Post on 24-Mar-2018
transcript
Air Products Oxyfuel CO2 Compression and Purification Developments
Vince White1, Kevin Fogash2 and Frank Petrocelli2
1 Air Products PLC, Hersham Place, Molesey Road, Walton-on-Thames, Surrey, KT12 4RZ, UK
2 Air Products & Chemicals, Inc, 7201 Hamilton Blvd, Allentown, PA, 18195 USA
2nd Oxyfuel Combustion Conference Yeppoon, Queensland, Australia 12th-16th September 2011
Oxyfuel CO2 Purification
2
• Oxyfuel combustion of coal produces a flue gas containing:
• CO2 + H2O
• Any inerts from air in leakage or oxygen impurities
• Oxidation products and impurities from the fuel (SOx, NOx, HCl, Hg, etc.)
Steam Boiler & Turbines
Coal
MWe
Flue Gas
Recycle
Oxygen
CO2 Purification& Compression
O2 Supply CO2 Transport & Sequestration
• Purification requires:• Cooling to remove water• Compression to 30 bar: integrated SOx/NOx/Hg removal• Low Temperature Purification
• Low purity, bulk inerts removal• High purity, Oxygen removal
• Compression to pipeline pressure
Air Products Oxy-Fuel CO2 Capture and Purification –
with Air Products PRISM® Membrane
3
Raw Flue Gas
Product CO2
Offgas[To Atmosphere]
Process Condensate
Heat Recovery
SourCompression &
AP Acid Gas Column
CondensateCollection
TSA UnitMercury Removal
CO2 Compression
Auto-Refrigerated N2, Ar, O2
RemovalProcess
Boiler Steam Cycle
OptionalAPCI PRISM®
Membrane
O2 and CO2 Rich[To Boiler]
Commercial
Mature Tech, Needs Data
Needs Engineering Data
Major Utilities
Cooling WaterElectric Power
Expander
Air Products’ CO2 Purification and Compression Technology for Oxyfuel
4
Sour CompressionSOx, NOx, Hg Removal
Auto-Refrigerated Inerts Removal
Ar, N2, O2
Air Products’ PRISM® Membrane For Enhanced
CO2 + O2 Recovery
Removal minimises compression and transportation costs.
Optional O2 removal for EOR-grade CO2
CO2 capture rate of 90% with CO2
purity >95%
CO2 capture rate depends on raw
CO2 purity which depends on air ingress
Inerts vent stream is clean, at pressure and rich in CO2 (~25%) and O2
(~20%)
Polymeric membrane unit –
selective for CO2 and O2 – in vent stream will recycle CO2 and O2 rich permeate stream to the boiler.
CO2 capture rate increases to >97% and ASU size/power reduced by ~5%
Commercial
Mature Tech, Needs Data
Needs Engineering Data
SOx/NOx removed in compression system
NO is oxidised to NO2 which oxidises SO2 to SO3
The Lead Chamber Process
FGD and DeNOx systems
Optimization
Elimination
Low NOx burners are not required for oxyfuel combustion
Hg will also be removed, reacting with the nitric acid that is formed
Air Products’ CO2 Purification and Compression Technology for Oxyfuel
5
Sour CompressionSOx, NOx, Hg Removal
Auto-Refrigerated Inerts Removal
Ar, N2, O2
Air Products’ PRISM® Membrane For Enhanced
CO2 + O2 Recovery
Removal minimises compression and transportation costs.
Optional O2 removal for EOR-grade CO2
CO2 capture rate of 90% with CO2
purity >95%
CO2 capture rate depends on raw
CO2 purity which depends on air ingress
Inerts vent stream is clean, at pressure and rich in CO2 (~25%) and O2
(~20%)
Polymeric membrane unit –
selective for CO2 and O2 – in vent stream will recycle CO2 and O2 rich permeate stream to the boiler.
CO2 capture rate increases to >97% and ASU size/power reduced by ~5%
Commercial
Mature Tech, Needs Data
Needs Engineering Data
SOx/NOx removed in compression system
NO is oxidised to NO2 which oxidises SO2 to SO3
The Lead Chamber Process
FGD and DeNOx systems
Optimization
Elimination
Low NOx burners are not required for oxyfuel combustion
Hg will also be removed, reacting with the nitric acid that is formed
NOx SO2 Reactions in the CO2 Compression System –
2005 model:
6
• We realised that SO2, NOx and Hg can be removed in the CO2 compression process, in the presence of water and oxygen.
• SO2 is converted to Sulfuric Acid, NO2 converted to Nitric Acid:
– NO + ½ O2 ⇌ NO2 (1) Slow
– 2 NO2 ⇌ N2O4 (2) Fast
– 2 NO2 + H2O ⇌ HNO2 + HNO3 (3) Slow
– 3 HNO2 ⇌ HNO3 + 2 NO + H2O (4) Fast
– NO2 + SO2 ⇌ NO + SO3 (5) Fast
– SO3 + H2O ⇌ H2SO4 (6) Fast
• Rate increases with Pressure to the 3rd power
– only feasible at elevated pressure
• Little Nitric Acid is formed until all the SO2 is converted
• Pressure, reactor design and residence times, are important.
Air Products’ CO2 Compression and Purification System: Removal of SO2, NOx and Hg
7
1.02 bar 30°C67% CO2
8% H2O25% InertsSOxNOx
30 bar to DriersSaturated 30°C76% CO2
24% Inerts
Dilute H2SO4
HNO3
Hg
Dilute HNO3
BFW
Condensate
cw
10- 15 bar
30 bar
Water
cwcw
30 MWth oxy-coal
pilot plant
160 kWth
oxy-coal rig
Cylinder fed
bench rig
London
Renfrew, Scotland
Schwarze Pumpe, Germany
1 MWth
slip stream
6 kWth
slip stream Batch
DOE/NETL Cooperative Agreement
Host: Alstom,Windsor, CT
0.3 MWth
slip stream
15 MWth
oxy-coal combustion unit
Ph
oto
cou
rtesy of V
atten
fallPh
oto
cou
rtesy of D
oo
san
Ba
bco
ck
Ph
oto
cou
rtesy of Im
peria
l College
Ph
oto
cou
rtesy of A
lstomP
ow
er
Path to Large-ScaleDemonstration
Large-Scale
(~300 MW)
Demo
9
AB
C
MFC
D
From NRTF
Flue Gas Cooler
Condensate
Separator
Compressor &
Receiver
Reactor
The effect of Pressure on SO2
and
NO Conversion (1 sl/min, 7 and 14 barg)
Inlet
After
Compressor &
ReceiverInlet
After
Compressor &
Receiver
(Point A) (Point C) (Point A) (Point C)
ppm SO2 900 20 98% 950 150 84%
ppm NOx 520 50 90% 390 120 68%
ConversionConversion
7 bar g14 bar g
Key Learnings from Imperial College Work
10
• NO oxidation rate confirmed to increase rapidly with increased pressure
• At low temperature (~ 30-50 °C), SO2 oxidation to SO3 / H2SO4 only occurs at an appreciable rate in presence of NO2 and a condensed phase
• Significant conversion can occur even with very small liquid phase volumes (i.e., very low L/G ratios)
– Speculation that condensation creates a fine mist with large interfacial surface area, and that reaction is occurring at the interface
– Speculation that reactions are accelerated at low pH
• Recognized need to develop internal capability to explore broader range of parameters and to increase rate of data generation
DOE/NETL Cooperative Agreement: Air Products’ Sour Compression PDU
11
Acid Reactor (C102)
Side View of PDU
• 1st campaign Jan 2010
• 2nd campaign April-May 2010
U.S. Department of Energy's National Energy Technology Laboratory under Award Number DE-NT0005309
DOE Project: Air Products’ Sour Compression PDU –Key Results
12
• For the overall process, total SO2 removal was 20-100 % (based on gas compositions).
• For the overall process, total NOx removal was 60-90 % (based on gas compositions).
• The effects of variations in the SO2/NOx feed ratio, column pressure, gas flowrate and liquid recirculation on the reactor performance were explored. Process performance was most sensitive to SO2/NOx feed ratio, over the range of parameter values investigated.
• SO2 was removed from the flue gas through both sulfite and sulfate mechanisms.
-100
0
100
200
300
400
500
600
700
20:38:24 20:52:48 21:07:12 21:21:36 21:36:00 21:50:24 22:04:48 22:19:12 22:33:36
ppm
v
Time
Oxyfuel 22 January 2010
[FLUGAS]NO.SCALED
[FLUGAS]SO2.SCALED
Condition DSOx Conversion >99%NOx conversion >90%(NOx zero +/- 20 ppmv)
Reactor Inlet Reactor Inlet Reactor Inlet Reactor Inlet
Reactor OutletReactor OutletReactor Outlet
Lab-Scale Reactor System
13
• Commissioned Sept. 2010 to further our understanding of SOx/NOx reaction chemistry during compression
• Wide range of conditions possible:
– Up to 3000 ppm SO2
– Up to 1000 ppm NOx
– Temperature range from ambient to 400 °C
– Pressure range from atmospheric to 30 atm
– 3 modes of operation:
– Dry gas
– Humidified gas
– Gas-liquid
Process Flow
CO2
O2
N2
SO2
/ N2
NO
/ N2
MFC
MFC
MFC
MFC
MFC
Gas Humidifier
Backpressure
Regulator
To Vent
To Analysis
Absorber
Column
High P
Water Pump
Recirc
Pump
Control
Valve
Water Flow
MFC
Sour Compression Modelling
14
• Concurrent with the technology demonstration projects, lab experiments and ASPEN modelling were carried out to develop a robust reaction model
• Goals of modelling:– Single reaction model to describe reactions in compression train and
in column– Use literature reactions and kinetics wherever possible– Same model can be used to describe lab data and to describe pilot
data from multiple configurations / scales (Renfrew, Windsor, Schwarze Pumpe)
• Modelling timeline:– 2005: 1st reaction model developed from literature references (no
data available at this time)– October 2009: research program with Imperial College initiated – September 2010: startup of Air Products lab reactor system– July 2011: Final version of reaction model developed from lab data
Sour Compression Model compared to experimental data
15
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0% 20% 40% 60% 80% 100%
Lab
un
it r
esu
lts
Model prediction
SO2 removal
NO conversion
N removal
N2O yield
45° line
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0% 20% 40% 60% 80% 100%
Lab
un
it r
esu
lts
Model Prediction
Compression Train Configuration
Column Configuration
Air Products Sour Compression System -Summary
16
• SOx/NOx removed in compression system
– NO is oxidised to NO2 which oxidises SO2 to SO3
– The Lead Chamber Process
• FGD and DeNOx systems
– Optimization
– Elimination
• Low NOx burners are not required for oxyfuel combustion
• Hg will also be removed, reacting with the nitric acid that is formed
Air Products’ CO2 Purification and Compression Technology for Oxyfuel
17
Sour CompressionSOx, NOx, Hg Removal
Auto-Refrigerated Inerts Removal
Ar, N2, O2
Air Products’ PRISM® Membrane For Enhanced
CO2 + O2 Recovery
Removal minimises compression and transportation costs.
Optional O2 removal for EOR-grade CO2
CO2 capture rate of 90% with CO2
purity >95%
CO2 capture rate depends on raw
CO2 purity which depends on air ingress
Inerts vent stream is clean, at pressure and rich in CO2 (~25%) and O2
(~20%)
Polymeric membrane unit –
selective for CO2 and O2 – in vent stream will recycle CO2 and O2 rich permeate stream to the boiler.
CO2 capture rate increases to >97% and ASU size/power reduced by ~5%
Commercial
Mature Tech, Needs Data
Needs Engineering Data
SOx/NOx removed in compression system
NO is oxidised to NO2 which oxidises SO2 to SO3
The Lead Chamber Process
FGD and DeNOx systems
Optimization
Elimination
Low NOx burners are not required for oxyfuel combustion
Hg will also be removed, reacting with the nitric acid that is formed
CO2 Compression and Purification System –Inerts removal and compression
18
Flue Gas Vent 1.1 bar~25% CO2
~75% inerts
Flue Gas
ExpanderAluminium plate/fin exchanger
Driers
Flue Gas
Heater
30 bar Raw CO2
Saturated 30°C75-85% CO2
CO2 product~96% CO2
~4% Inerts-60°C dp
-55°C
Auto-Refrigerated Inerts Removal
19
• Removal of impurities minimises compression and transportation costs.
• O2 can be removed for EOR-grade CO2
• CO2 capture rate of 90% with CO2 purity >95%
• CO2 capture rate depends on raw CO2 purity which depends on air ingress
– Increases from zero at 25mol% to 90% at 75mol%
– Reducing air ingress increases CO2 capture rate
Air Products’ CO2 Purification and Compression Technology for Oxyfuel
20
Sour CompressionSOx, NOx, Hg Removal
Auto-Refrigerated Inerts Removal
Ar, N2, O2
Air Products’ PRISM® Membrane For Enhanced
CO2 + O2 Recovery
Removal minimises compression and transportation costs.
Optional O2 removal for EOR-grade CO2
CO2 capture rate of 90% with CO2
purity >95%
CO2 capture rate depends on raw
CO2 purity which depends on air ingress
Inerts vent stream is clean, at pressure and rich in CO2 (~25%) and O2
(~20%)
Polymeric membrane unit –
selective for CO2 and O2 – in vent stream will recycle CO2 and O2 rich permeate stream to the boiler.
CO2 capture rate increases to >97% and ASU size/power reduced by ~5%
Commercial
Mature Tech, Needs Data
Needs Engineering Data
SOx/NOx removed in compression system
NO is oxidised to NO2 which oxidises SO2 to SO3
The Lead Chamber Process
FGD and DeNOx systems
Optimization
Elimination
Low NOx burners are not required for oxyfuel combustion
Hg will also be removed, reacting with the nitric acid that is formed
Can we improve on ~90% CO2 Capture?Vent stream is at pressure and is CO2 (and O2) rich
21
Flue Gas Vent 1.1 bar~25% CO2
~25% O2
~50% N2
Flue Gas
ExpanderAluminium plate/fin exchanger
Driers
Flue Gas
Heater
30 bar Raw CO2
Saturated 30°C75-85% CO2
CO2 product~96% CO2
~4% Inerts-60°C dp
-55°C
Air Products Oxy-Fuel CO2 Capture and Purification – with Air
Products PRISM® Membrane
22
Flue Gas Expander
Aluminium plate/fin exchanger
Driers
Flue GasHeater -55°C
Membrane
To Boiler
CO2 product~96% CO2
~4% Inerts-60°C dp30 bar Raw CO2
Saturated 30°C75-85% CO2
Advantages of Air Products’ CO2Purification Technology for Oxyfuel
23
• Inerts vent stream is clean, at pressure and rich in CO2 (~25%) and O2 (~20%)
• Polymeric membrane unit – selective for CO2 and O2 – in vent stream will recycle CO2 and O2 rich permeate stream to the boiler.
• CO2 capture rate increases to >97% and ASU size/power reduced by ~5%
Membrane skid at the Air Products – VattenfallOxyfuel Pilot Plant
The Vattenfall – Air Products Oxyfuel CPU Pilot Plant
24
Air Products’ CO2 Purification Unit (CPU) Pilot Plant at Vattenfall’s Schwarze Pumpe
25
Raw Flue Gas
CO2 ReturnedTo OxPP
Inerts Vent[To OxPP]
Process Condensate
SourCompression
CondensateCollection
TSA UnitMercury Removal
Auto-RefrigeratedInerts +O2
Removal Process
Air ProductsPRISM®
Membrane
O2 and CO2 Rich[To OxPP]
26
50/50 Flue Gas Mix From Before and After OxPP FGD
27
50/50 Flue Gas Mix From Before and After OxPP FGD
0
50
100
150
200
250
300
350
400
942 947 952 957 962 967
NO
an
d N
O2
(pp
m, D
ry)
Time (minutes)
NO
NO2
Inlet K432 Inlet Column Exit Column
NOx
Conclusions
28
• Purification of the CO2 from oxyfuel-fired coal power plants is a technology ready for commercialisation
• Several advances in CPU technology have been described which will improve the performance of the CPU and the power plant
• Air Products is developing commercial offerings for CPU plants on demonstration plants
Acknowledgment: “A portion of this material is based upon work supported by the Department of Energy's National Energy Technology Laboratory under Award Number DE-NT0005309.”
Disclaimer: “This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.”
Thank you
www.airproducts.com