SSantos - Hg Presentation (MEC7) - ieaghg

Challenges in Understanding the
Fate of Mercury during Oxyfuel Combustion
Stanley Santos
IEA Greenhouse Gas R&D Programme
Cheltenham, UK
Email: stanley.santos@ieaghg.org
MEC7 Workshop
DLCS, Strathclyde University
18 th June 2010

IEA Greenhouse Gas R&D
Programme
• A collaborative research programme founded in 1991
• We are the sister organisation of IEA Clean Coal Centre
• Aim: Provide members with definitive information on
the role that technology can play in reducing
greenhouse gas emissions.
• Producing information that is:
� Objective, trustworthy, independent
� Policy relevant but NOT policy prescriptive
� Reviewed by external Expert Reviewers
� Subject to review of policy implications by Members
• Funding approx 3 million €/year
2

Contracting Parties and Sponsors
3

Acknowledgement
• IEA Clean Coal Centre
• Lesley Sloss
• Robert Davidson
• Vattenfall R&D AB
• Marie Anheden
• Jinying Yan
• E.On Engineering UK
• Robin Iron
• Utah University
• Prof. Jost Wendt
• Leeds University
• IHI
• Maryam Gharebaghi
• Richard Porter
• Toshihiko Yamada
• Doosan Babcock
• Jacqueline Gibson
• Connie Ellul
• Bhupesh Dungel
• Stuttgart University
• Jorge Maier
• Air Products
• Vince White
• Air Liquide
• Jean Pierre Tranier
• Praxair
• Minish Shah
4

Special Workshop on Oxyfuel Combustion
SO2/SO3/Hg/Corossion Issues in
Oxyfuel Combustion Boiler
London, UK
25 th – 26 th January 2011
Email: stanley.santos@ieaghg.org
Area of Discussions:
1) Fundamental Experimental work on SO2/SO3/Hg emission
from oxyfuel combustion boiler
2) SO2/SO3/Hg/Cl measurement techniques under oxyfuel
combustion conditions
3) Impact of Sulphur species to the Flue Gas Processing Units
(ESP/FF, FGD, Direct Contact Cooler, Wet Scrubbers)
4) Boiler Corrosion issue – under oxyfuel combustion conditions
5) Modelling work on SO2/SO3/Hg from oxyfuel boilers
6) Experience from large scale demonstration/pilot plant projects
5

Presentation Outline
• Objective of this Presentation
• Brief Introduction
• Oxyfuel combustion of power plant with CO2
capture
• Why we need to understand the fate of Hg
during combustion?
• Review of Literature – Where are we in our
understanding of fate of Hg during oxyfuel
combustion.
• Where are the challenges.
6

Objectives of this Presentation
• To provide awareness the impact / risk of
ignoring Hg in any Oxy-Coal Combustion Power
Plant with CO2 Capture Power Plant
• To initiate discussion on the issue of Mercury in
Oxy-Coal Combustion Power Plant with CO2
Capture
• To initiate a review on the different factors to
reconsider on the design of coal power plant in
the perspective of Hg.
7
7

Oxy-PC Combustion Fired Power Plants
with CO2 Capture
8

Oxy-Coal Combustion Power Plant with CCS…
9

Where Can You Extract the Recycled Flue Gas (RFG)
(For Practical application using low S coal)
10

Alstom Schwarze Pumpe 2008 30MWth Lignite
Hitachi Babcock Schwarze Pumpe 2010 30MWth Lignite
IHI Callide 2011 30MWe Coal
Alstom / AL Lacq 2009 30MWth Gas/Oil?
CIUDEN El Bierzo CFB Facility 2011 30MWth Coal
CIUDEN El Bierzo PC Facility 2010 20MWth Coal
ENEL HP Oxyfuel Brindisi Test Facility 2012 48MWth Coal
1980’s
1990 - 1995
ANL/Battelle/EERC completed the first
industrial scale pilot plant
2003 - 2005
Vattenfall (ENCAP ++)
1998 – 2001
CS Energy / IHI Callide Project
CANMET
US DOE Project / B&W / Air Liquide
EC Joule Thermie Project
- IFRF / Doosan Babcock / Int’l Combustion
NEDO / IHI / JCoal Project
Updated by S. Santos (17/06/2010)
2007
2008
Vattenfall - Janschwalde (PC -250MWe)
KEPCO/KOSEP - Yongdong (PC - 100MWe)
Endesa/CIUDEN - El Bierzo (CFB - 300MWe)
2009 – Lacq – World’s
first 30MWt
retrofitted Oxy-NG
boiler
World’s FIRST 30 MWt
full chain demonstration
at Schwarze Pumpe Pilot Plant
B&W CEDF (30MWt)
large scale burner testing started
First large scale 35MWt
Oxy-Coal Burner Retrofit
Test done by
International Combustion
2011 – Callide –
World’s first 30MWe
retrofitted Oxy-coal
power plant
2011 – CIUDEN –
World’s first 30MWt
Oxy-CFB Pilot Plant
By 2014-2018
Demonstration of
50– 300MWe full
scale power plant.
Target :
“Commercialised by 2020”
By the end of 2010/2011,
Users (i.e. Power Plant Operators)
will have 6 burner manufacturers
fully demonstrating “Utility Size
Large Scale Burners” which should
give a high level of confidence
toward demonstration
B&W CEDF 2008 30MWth Coal
Alstom Alstom CE 2010 15MWth Coal
Doosan Babcock DBEL - MBTF 2009 40MWth Coal

Today... There are 3 Major Full Scale
PC Burner Testing Facilities Worldwide Retrofitted for Oxyfuel
• Babcock and Wilcox (B&W)
30MWth CEDF
• Barberton, Ohio, USA
• Start of Operation: Oct. 2008
• Wall Fired Burner
Development
• Doosan Babcock –
40MWth in 90MWth MBTF
• Renfrew, Scotland, UK
• Start of Operation: Jun. 2009
• Wall Fired Burner
Development
• Alstom Power Plant Lab. –
15MWth in 30MWth BSF
• Windsor, Connecticut, USA
• Start of Operation: Nov. 2009
• T-Fired Burner Development
Courtesy of Alstom, B&W and Doosan Babcock
12
12

© Vattenfall AB
Jänschwalde demonstration plant – view from south east
Fuel feeding
Lignite
dryer
Oxyfuel
boiler
ASU
Flue gas cleaning
14
Cooling water
pump
CO 2-compression
PCC
Preparation and cleaning of
Lignite condensate
NH 3-storage
CO CO2-compression 2-compression
CO 2-transport

Why it is important to understand the fate of
mercury during Oxyfuel Combustion?
Why Mercury is an operational issue to
Oxyfuel Combustion Power Plant?
Case 1: Moomba Gas Plant
Case 2: Skikda Gas Processing Plant
15

Case 1: Moomba Gas Plant
Accident caused by Mercury
• Moomba Gas Processing Plant, owned by Santos, is the
main supplier of natural gas to South Australia and New
South Wales
• Liquids separated from raw natural gas via 2 trains of LRP (Liquids
Recovery Plant)
• Liquids (condensate and LPG) sent to Port Bonython for export (about
650Km south of Moomba)
• A New Year BANG! About 02.43 in the morning, 1st
January 2004 – an explosion & fire occurred at Train A of
the LRP section.
• The fire incident also damaged Train B.
• Effect: liquids production interrupted for 8 months
16

Failure Location
• Failure occurred at the base (6 o’clock) of the gas nozzle
• Evidence of de-lamination consistent with Liquid Metal
Embrittlement (LME) caused by mercury in contact with
aluminium
17

Case 2: Skikda Gas
Processing Plant Accident
• Skikda Gas Processing Plant is owned by Sonatrach in
Algeria.
• About 18.40 on 19 th January 2004 (just about 3 weeks
after Moomba Gas Processing incident), an explosion
occurred in Train “40”.
• Consequence:
• 3 out of the 6 NG liquefaction trains were destroyed and 2, which
were not operating at the time, were damaged. The administration
building and the maintenance workshop, and other buildings, were
completely destroyed.
• Sadly, 27 person killed and 80 people injured.
• Adjacent oil refinery and power plant were shut down due to the blast
for at least a month.
18

Skikda Gas Processing
Accident
19

Incident Report
• The Report concludes that the explosion was the
consequence of a catastrophic failure in one of the cold
boxes of Unit “40”, which led to a vapour cloud explosion of
either LNG or refrigerant. The most probable source of
ignition was the boiler at the north end of Unit “40”.
• Although (unlike the Moomba Gas Plant incident) – the report
noted that it is not absolutely proven if Liquid Metal
Embrittlement is the main cause of the failure – nonetheless,
it was accepted that this was the most likely probable cause
of the failure.
• Train “40” is the only NG Liquefaction train that doesn’t have
mercury removal system!
20

Discussion Points
21

Flue Gas
Vent
1.1 bar
20°C
25% CO 2
75%
inerts
22
Driers
CO 2 Compression and Purification System –
Inerts removal and compression to 110 bar
Flue Gas
Expander
30 bar Raw CO 2
Saturated 30°C
76% CO 2 24% Inerts
Flue Gas
Heater
Aluminium plate/fin exchanger
-55°C
CO 2 product
110 bar
96% CO 2
4% Inerts
-60°C dp

Statement of Fact:
• For oxyfuel combustion – Mercury is not
an environmental issue alone but also an
operational issue particularly to the CO2
processing unit.
• The issue of Mercury to oxyfuel
combustion is not about concentration –
but it is about where Mercury could
accumulate within the CO2 processing
unit!
23

Discussion Points
(Oxyfuel Boiler)
Where we are in the understanding of:
• NOx Chemistry during combustion
• SO2/SO3/Dew Point
• Chlorine issue (Halogen issue)
• Carbon in Ash
• Brief review of some results presented
regarding Hg under oxyfuel condition
24

Coal Combustion under CO 2 Atmosphere
Item Combustion with air Combustion with oxygen
Windbox O2 21% 21%
21~30%
21~30%
N2 79% 79% (0)~10%
(0)~10%
CO2 0% 40~50%
40~50%
H2O Small 10~20%
10~20%
Others - NOx、SO2・・・
Flue gas O2 3~4% 3~4% 3~4%
3~4%
3~4%
N2 70~75% 70~75% (0)~10%
(0)~10%
CO2 12~14% 12~14% 60~70%
60~70%
H2O 10~15% 10~15% 20~25%
20~25%
Others NOx、SO2・・・ NOx、SO2・・・
(Wet % base)

NOx Emissions
- We have quite a good confidence in
knowing the trend of these emissions
26

NOx Results from IFRF study (APG4)
27

SO2 Emissions
- Highly dependent on how
sulphur is captured in ash...
- without the removal of SO2 in the secondary RFG, it should
noted that about ~30% reduction could be achieved (on mass
per unit energy input basis – especially for bituminous coal)
28

SO2 Emissions
(Results from IFRF)
29
29

SO3 Emissions
(Results from ANL-EERC, IVD Stuttgart, Callide/IHI Aiolo)
SO3 Concentration (ppm)
20
18
16
14
12
10
8
6
4
2
0
ANL - Air ANL - Oxy
IVD Stuttgart - Air IVD Stuttgart - Oxy
Callide IHI - Coal A - Air Callide IHI - Coal A - Oxy
Callide IHI - Coal B - Air Callide IHI - Coal B - Oxy
0 250 500 750 1000 1250 1500 1750 2000 2250
SO2 Concentration (ppm)
30

Correlation of SO 3-Moisture and Acid Dew Point
(Result from Stuttgart University – IFK)
Säuretaupunktstemperatur [°C] .
Acid dew point temperature
160
150
140
130
120
110
100
90
80
Luft
air
Oxyfuel
0,5 ppm SO3 1,0 ppm
2,0 ppm 5,0 ppm
10,0 ppm
0 10 20 30 40
Wasserdampfkonzentration im Rauchgas [Vol. %]
Moisture content in flue gas
31

SO 2 captured along the convective part
(down to 450°C) by different inlet concentrations
Coal
Type
Iron
Content
in the
Ash
“KK” ~2-3%
“EN” ~17-18%
“LA” ~22-23%
“RH” ~16-17%

Chlorine / Bromine Chemistry
- This could be a big challenge to Oxyfuel
Combustion because we hardly know anything
about it under oxyfuel combustion condition.
- But ... What we currently know shows the
possible impact of Chlorine and Sulphur to boiler
corrosion.
33

CORROSION - Low-S/Low-Cl
95%ile Parabolic Rate (cm2 s-1 95%ile Parabolic Rate (cm )
1.00E-09
1.00E-10
1.00E-11
1.00E-12
1.00E-13
1.00E-14
El Cerrejon Oxy-Fuel
400 450 500 550 600 650 700
Temperature ( o C)
T22
T91
E1250
TP347HFG
HR3C
San25
IN740
Thema Datum Bereich
Seite 34

CORROSION - High-S/High-Cl
95%ile Parabolic Rate (cm2 s-1 95%ile Parabolic Rate (cm )
1.00E-09
1.00E-10
1.00E-11
1.00E-12
1.00E-13
1.00E-14
Thoresby Oxy-Fuel
400 450 500 550 600 650 700
Temperature ( o C)
T22
T91
E1250
TP347HFG
HR3C
San25
IN740
Thema Datum Bereich
Seite 35

Addition of Calcium Chloride or
Calcium Bromide to enhance
oxidation of Hg may probably be a
none starter under oxyfuel
combustion conditions!!!
I could be a “villain” to a lot of commercial
interests to this type of Hg reduction control
technology!
But will the addition of other Calcium/Magnesium
compounds enhance Hg removal???
36

Carbon in Ash
- This could be dependent to the burner design
and combustion regime.
- It is expected that a lower Carbon in Ash during
oxyfuel combustion conditions
37

Would the capture of SO2 / SO3 in the ash
enhanced by lower carbon in ash?
Marrier and Dibbs (1974) Thermochimica Act (Vol. 8)
E.ON UK Results at 26%O2
38
38

Review of Literature
- Assessing all the published worked relevant to
Mercury and oxyfuel combustion
- Aim: My attempt to establish what we know...
39

Mercury
Speciation
• Hg measured by on-line analyzer
• Hg data taken when firing lignite
• Hg in flue gas (air firing) was ≈ 13.5µg/m 3
• Hg concentration in flue gas increase in oxy mode
corresponded to removal of N2. • Oxidized (ionic) Hg increased from 25% to 30%
� Increases removal (less elemental Hg)
• Oxidized Hg removed in WFGD
CONCLUSIONS:
1. Hg oxidation may improve with oxycombustion
2. Hg removal is expected to be the same as for air firing
© 2009 Babcock & Wilcox Power Generation Group, Inc. All rights reserved. .40

Experimental Results from Guo et. al. (2009)
Thermal Degradation of 3 Chinese Coal
41

Suriyawong et. al. (2005)
42

List of Literature
• Gharebaghi, M., Goh, B., Porter, R.T.J., Pourkashanian, M. and Williams, A.. (2009). Assessment
of Fate of Mercury in Oxy-coal Combustion. 1st International Oxyfuel Combustion Conference
(OCC1). Cottbus, Germany. (8-11 September 2009). IEA Greenhouse Gas R&D Programme.
• Gharebaghi, M., Hughes, K.J., Porter, R.T.J., Pourkashanian, M. and Williams, A.. (2010). Mercury
Speciation in Air- and Oxy-Coal Combustion: A Modelling Approach. 33rd International
Symposium on Combustion. Beijing, China.
• Guo, S., Yang, J., Liu, Z., and Xiao, Y.. (2009). Behaviour of Mercury Release During Thermal
Decomposition of Coals. Korean Journal of Chemical Engineering. Vol. 26, pp. 560-563.
• McDonald D.K., DeVault D., Tranier J.P., Perrin N. (2009). Oxyfuel Process Developments Leading
to Demonstration Plant Design. 1st International Oxyfuel Combustion Conference (OCC1).
Cottbus, Germany. (8-11 September 2009). IEA Greenhouse Gas R&D Programme.
• Pavlish, J.H., Hamre, L.L. and Zhuang, Y.. (2010). Mercury Control Technologies for Coal
Combustion and Gasifications Systems. Fuel. (Vol. 89) pp. 838-847.
• Santos, S.O. (2006). Mercury (Hg) in Oxy-Coal Fired Power Plant with CO2 Capture -What is the
Real Score? 3rd IEAGHG International Oxyfuel Combustion Research Network Workshop.
Yokohama, Japan. (5-6 March 2008).
•
43

List of Literature
• Sethi V., Omar K., Martin P., Barton T., Krishnamurthy K. (2007). Oxy-Combustion Versus Air-
Blown Combustion of Coals. in “The Power of Coal.” The Proceedings of the 32nd International
Technical Conference on Coal Utilization & Fuel Systems. Clearwater, FL, USA, 10-15 Jun 2007.
•
• Suriyawong A., Gamble M., Lee M.H., Axelbaum R., Biswas P. (2006). Submicrometer Particle
Formation and Mercury Speciation under O 2-CO 2 Coal Combustion. Energy and Fuels. (Vol. 20),
pp. 2357-2363.
•
• Suriyawong A., Gamble M., Lee M.H., Axelbaum R., Biswas, P. (2005). Submicrometer Particle
Formation and Mercury Speciation under Oxygen-Carbon Dioxide Coal Combustion.
Proceedings, 22nd Annual Pittsburgh Coal Conference, Pittsburgh, PA, USA, 12-15 Sep 2005.
Pittsburgh, PA, USA, Pittsburgh Coal Conference, paper 275, 10 pp (2005) CD-ROM
•
• Wall T., Liu Y., Spero C., Elliott L., Khare S., Rathnam R., Zeenathal F., Moghtaderi B., Buhre B.,
Sheng C., Gupta R., Yamada T., Makino K. and Yu J. (2009). An Overview on Oxyfuel Coal
Combustion - State of the Art Research and Technology Development. Chemical Engineering
Research and Design (Vol. 87). pp. 1003-1016.
44

Discussion Points
(CO2 Processing Unit)
45

Flue Gas
Vent
1.1 bar
20°C
25% CO 2
75%
inerts
46
Driers
CO 2 Compression and Purification System –
Inerts removal and compression to 110 bar
Flue Gas
Expander
30 bar Raw CO 2
Saturated 30°C
76% CO 2 24% Inerts
Flue Gas
Heater
Aluminium plate/fin exchanger
-55°C
CO 2 product
110 bar
96% CO 2
4% Inerts
-60°C dp

47
NOx SO 2 Reactions in the CO 2
Compression System
� We realised that SO 2, NOx and Hg can be removed in the CO 2
compression process, in the presence of water and oxygen.
� SO2 is converted to Sulphuric Acid, NO2 converted to Nitric
Acid:
–
–
NO + ½ O2 2 NO2 =
=
NO2 N2O4 (1) Slow
(2) Fast
– 2 NO 2 + H H2O 2O = HNO 2 + HNO 3 (3) Slow
– 3 HNO 2 = HNO 3 + 2 NO + H 2O (4) Fast
– NO 2 + SO 2 = NO + SO 3 (5) Fast
– SO 3 + H 2O = H 2SO 4 (6) Fast
� Rate increases with Pressure to the 3 rd power
– only feasible at elevated pressure
� No Nitric Acid is formed until all the SO 2 is converted
� Pressure, reactor design and residence times, are important.

48
CO 2 Compression and Purification System –
Removal of SO 2, NOx and Hg
1.02 bar
30°C
67% CO2 8% H2O 25%
Inerts
SOx
NOx
� SO 2 removal: 100% NOx removal: 90-99%
BFW
Condensate
cw
15 bar
Dilute H 2SO 4
HNO 3
Hg
30 bar
cw
Water
Dilute HNO 3
30 bar to Driers
Saturated 30°C
76% CO 2
24% Inerts
cw

NG Industry Practice
• Activated Carbon bed is
generally employed. This is
expected to be applied to
oxy-combustion oxy-PC as
well.
• It is important to be aware
with regard to short term
performance drop of the
activated carbon bed
during shut down or
process upset.
• Competing reaction of Hg
and Sulphur species
50

Flue Gas
Vent
1.1 bar
20°C
25% CO 2
75%
inerts
51
Driers
CO 2 Compression and Purification System –
Inerts removal and compression to 110 bar
Flue Gas
Expander
30 bar Raw CO 2
Saturated 30°C
76% CO 2 24% Inerts
Flue Gas
Heater
Aluminium plate/fin exchanger
-55°C
CO 2 product
110 bar
96% CO 2
4% Inerts
-60°C dp

What is the Feasibility and Effectiveness of Cold
Trapping of Hg as final polishing process?
(Figure from US Patent 4982050)
• Hg is heavier than the gas at temperature
colder than -10 o C (solid at -40 o C)
52

Summary and Conclusions
• For any oxy-combustion process, the
removal of mercury from the CO2 rich flue
gas is a necessary to protect key
components in the CO2 clean up and
processing unit.
• Damage cause by Mercury to any
aluminium based equipment is a Random
Event!!!
53

Understanding Failure
Mechanisms
• Statement from ALPEMA:
In general, mercury will not react with aluminium unless it is
allowed to exist in contact with the heat exchanger in its liquid
state and there is water present. If these conditions exist within a
heat exchanger, then mercury contamination can result in
problems. This attack is most severe when coupled with another
corrosion process.
• Currently, the common practice of NG
Processing means reducing the mercury to
less than 0.01 µg/Nm3.
• QUESTION: Is the 0.01 µg/Nm 3 to be used as
well in the oxy-coal combustion power plant?
54
54

Summary and Conclusions
• What is the speciation of Hg in an oxycoal
combustion cases?
• Together with this challenge is how we measure
the speciation under oxyfuel combustion
condition?
• How we deal with the impact of:
• Higher concentration of NOx, SOx, HCl, HBr,
CO2, etc...
55

Role of Chlorine and its
Chemistry
• What is the role of Coal Chlorine and its
Chemistry to the heterogeneous and gas
phase oxidation of Hg under oxyfuel
condition.
• SO 2(g) + Cl 2(g) + H 2O(g) ↔ 2HCl(g) + SO 3(g)
56

Impact of SO3 on Hg Removal Efficiency
of the Activated Carbon
Air Fired Case (CODEN Study) Oxy Fired Case
57

Mercury Management in the CO2 Processing Plant
• I don’t see any technical barrier in
removing Hg. This has been done in LNG
industry. The consideration of cost is the
main question!
• There are 3 levels where Hg (both
elemental and ionic) could be captured in
the CO2 processing plant.
• Compression stage
• Moisture Removal stage
• Activated Carbon Guard bed
58

CS Energy/IHI Burner Testing Programme at
Callide A Power Station
• Callide A Project – would be the world’s 1 st oxyfuel
retrofitted power station. (Would be the largest
demonstration of the technology by 2011!)
• First oxyfuel pilot plant that will actually
produce electricity.
• Installation of new IHI 2x ~30MWth Wall Fired
Burners (with operation of 4 burners at full
load)
o A unique position to provide information related to
the burner – burner interaction
• Project Scope (4 years operation):
o Oxygen plant (nominal 2 x 330 tpd ASUs)
o Boiler refurbishment and oxy-fuel retrofit (1 x 30
MWe Unit)
o CO2 compression & purification (75 tpd process
plant from a 20% side stream)
o Road transport and geological storage (~ 30 tpd
liquid CO2)
Courtesy of CS Energy, IHI
60

Interest to receive updates - Please Register at:
Conference Dates:
www.ieaghg.org/index.php?/create-an-account.html
12th 12 Sept. 2011 Asia Pacific Programme - Oxyfuel Working Group Capacity Building Course
th Sept. 2011 Asia Pacific Programme - Oxyfuel Working Group Capacity Building Course
12 th –15 th Sept. 2011 2nd Oxyfuel Combustion Conference
16 th Sept. 2011 Facility Visit to Callide Power Station
Dates to Remember:
15 th Sept. 2010 Call for papers opens
15 th Dec. 2010 Deadline for Abstract Submission
15 th Feb. 2011 Conference Registration opens
15 th Apr. 2011 Notification of Acceptance for Oral / Poster Presentations
15 th May 2011 Early Bird Registration Deadline
12 th – 16 th Sept. 2011 2 nd International Oxyfuel Combustion Conference
61