The Relevance of Oxy-fuel Technology for Japan...0 0.5 1 1.5 2 2.5 3 3.5 N2/O2 CO2/O2 CO2/O2,k=0...

Tokyo Institute of TechnologySchool of Engineering

Ken OKAZAKIProfessor, Dept. of Mechanical and Control Engineering

Graduate School of Science and EngineeringTokyo Institute of Technology (Tokyo Tech), Japan

The 4th Oxy-fuel Capacity Building CourseTokyo Institute of Technology, Japan

September 2-3, 2012

The Relevance of Oxy-fuel Technologyfor Japan

Inter-Departmental Organizationfor Environment and Energy

1


Outline1. Key issues to mitigate the global

warming

2. Clean and high efficiency coal technology in Japan

3. Important role of CCS

4. Oxy-fuel combustion (pulverized coal)• Origin, history (past – present - future)• Basic studies (lab. scale, pilot scale)• Callide Project (Australia-Japan)• Future prospect (demonstration, commercial)

5. Concluding remarks 2


3


• Global warming is due to an extraordinary large amount of CO2 emissions.

• Net and quantitative contribution to CO2 reduction is the most important (large scale).

• Contribution of renewable energies is important but very small at present.

• Technologies to suppress CO2 emissions still depending on fossil fuels are urgent issues (ex. coal-fired power stations with CCS, integration of fossil fuels with hydrogen energy system).

• Only energy-saving or high efficiency is definitely not enough.

• Harmony among public society, technology innovations and economical growth.

• Fair and effective collaboration among all major countries including both developed countries and developing countries.

Key Issues of Countermeasures for Global Warming

4


55

(Far future)

CO2 + H2Fossil Fuel(Coal, Oil ..)

O2/CO2

Combustion

CO2 Recovery

Air-blownCombustion

CO2 Separationand Recovery(MEA, KS-1 ..)

CO + H2

gasificationshift reaction

Hydrogen Energy Systemwith Exergy Regeneretion

(Fuel Cell …)

Renewable Energy(Wind, PV ..)

Electricity

H2 + O2 H2O

CO2 Sequestration(Ocean, Geological ..)

CO2 + H2

(Future)

FutureGen

steam reforming

exergy enhancementof low quality waste heat

CO2 + H2CO2 + H2Fossil Fuel(Coal, Oil ..)

O2/CO2

Combustion

CO2 Recovery

Air-blownCombustion


CO + H2



(Fuel Cell …)


Electricity

H2 + O2 H2O

CO2 Sequestration(Ocean, Geological ..)CO2 Sequestration(Ocean, Geological ..)

CO2 + H2

(Future)

FutureGen

steam reforming


Integration of Fossil Fuel, Hydrogen and CO2 Sequestration

Roadmap toward Sustainable Economy

Oxy-firing

Feb. 27, 2003

<Okazaki, J. Energy, 2004>(Short term)

(Medium term)

CO2 + H2Fossil Fuel(Coal, Oil ..)

O2/CO2

Combustion

CO2 Recovery

Air-blownCombustion


CO + H2



(Fuel Cell …)


Electricity

H2 + O2 H2O

CO2 Sequestration(Ocean, Geological ..)

CO2 + H2

(Future)

FutureGen

steam reforming


CO2 + H2CO2 + H2Fossil Fuel(Coal, Oil ..)

O2/CO2

Combustion

CO2 Recovery

Air-blownCombustion


CO + H2



(Fuel Cell …)


Electricity

H2 + O2 H2O

CO2 Sequestration(Ocean, Geological ..)CO2 Sequestration(Ocean, Geological ..)

CO2 + H2

(Future)

FutureGen

steam reforming


Nuclear Energy

5


Coal Flow around the World (Outlook 2009)

6


Coal is Japan’s Lowest Cost Option in Post-Nuclear Age

7


(Net efficiency : 42%)

8


Present Status of Clean Coal Technology in Japan

NOxand SOxemissions from fossil fuel fired power stations

Acid Raintechnology transferfrom Japan

CO2 Problemsonly increase of eff.is not enough, andnew strategies are definitely necessary.

In Japan1 GW P.C. Stations

Net eff. > 40 %NOx< 100 ppm

U.S.A. Can. U.K. Fra. Ger. Ita. Jap.

NOx: 0.017, SOx: 0.070 (Isogo No.1)

9


Startup year

No.1 Isogo Ｐｏｗｅｒ Station

(Press.)

(16.6)

(24.1)

450

483485

538

566 593

(31.0)

Temp.

5

10

15

20

25

600

550

500

450

400

Ste

am p

ress

ure

( M

Pa

)

(4.1)

‘55 ‘60 ‘65 ‘70 ‘90 ‘95 2000

30

~~

~

610

~~

~

Ste

am te

mpe

ratu

re（℃）

620

Change of Steam Conditions of Coal-Fired Power Plant in Japan

(USC)

Nikkei Newspaper, Sept.8, 2008Steam temp. : → 700 ℃Net efficiency42% → 46% (2015) → 48% (2020)

Hitachi, Toshiba, MHI

10


Efficiency of Coal-fired Power Generation in Various Countries(LHV, %)

11


12


13


14

CO2 recovery from coal-fired power station

２．Post-combustion system (From flue gas)

３．Oxy-fuel combustion system

ASU

Coal（C,H,O,N,S,Ash） Boiler

Flue gas recycle （CO2，・・・）H2O，SO2

O2

Air（N2、O2）

N2，O2N2

Flue gas treatment

ASU

O2

Air（N2、O2）

N2

Gasifier Syngas treatmen

tCO shift

CO2 storage/sequestration

Compress/Cooling

CO2 separation

GTHRSG

Coal（C,H,O,N,S,Ash）１．Pre-combustion system (Gasifier)

Boiler

CO2

Coal（C,H,O,N,S,Ash）Air（N2、O2）

N2，H2O，O2

Flue gas treatment

CO, H2 CO2, H2

H2



Compress/Cooling

Compress/Cooling

14


Panel: Oxy-Fuel Technology

Oxy-Fuel Technology I : Overview & Demonstrations

Oxy-Fuel Technology II : Emissions

Oxy-Fuel Technology III: Experimental Studies

Oxy-Fuel Technology IV: Understanding Oxy-Combustion Impacts

Oxy-Fuel Technology V : Burner Developments

Presentations

2004 No presentation

2005 One presentation

2006 One session

2007 Full sessions (full of audience)

… …

2011 Full sessions (full of audience)

Oxy-Coal Combustion

15


July 13, 2012

16


Part IIntroduction to oxy-fuel combustion

Part IIOxy-fuel combustion fundamentals

Part IIIAdvanced oxy-fuel combustion concepts and developments

Contents

“Oxy-fuel combustion for power generation and carbon dioxide (CO2) capture”

Editted by Ligang Zheng

17


18


Oxyfuel system development history in Japan

Oxyfuel basic study was performed from 1990 Demonstration Ready by the end of 1990’s Demonstration Project was conducted from 2004, and operation started

in March, 2012

201520102005200019951990

The first national Oxyfuel R&D project in Japan

Japan and Australia Joint Demonstration Project

Now

2020

Demonstration ReadyBasic Study(NEDO)

Feasibility Study(NEDO)

Callide Project(METI/NEDO)

Application Study

Demonstration

Future Study

19


O2/CO2 (Oxy-firing) Coal CombustionConventional pulverized coal combustion

CO2 concentration in flue gas is about 13 %

Great energy consumption to separate CO2

O2/CO2 pulverized coal combustion

CO2 concentration in flue gas is enriched up

to 95 %

Easy and efficient CO2 recovery

Small amount of exhausted gas (extremely low amount of NOx, SOx)

O2

Coal

Recycled gas

O2 productionAir

Furnace

Practically realized by IshikawajimaharimaCo., Ltd. ASU

<Okazaki, Ando, ENERGY, 1997>

Oxy-firing of coal

20


CoalBoiler

GRF

AH

Stack

CO2 tank

CO2 liquefaction

Non-condensable gas

Flue gas treatment & compressor Cold Box

(CO2, H2O, SO2…)

FFFGLPH

<Oxyfuel boiler>

Mill

O2Air

N2

ASU

< CO2 capture process >

<Oxygen production & supply>

Study Items for Commercialization

Oxyfuel Boiler (Furnace) Combustion characteristics Flame stability Radiation heat transfer

Oxygen production & supply Method & System Oxygen purity

Oxyfuel Plant (Integrated operation) Performance (Boiler Efficiency, CO2 capture rate) Control (Oxyfuel, MFT) Operation

(Mode change, Load range, Start-up, Shut-down) Durability and Safety

CO2 Capture Process System Optimization Impurities Removal Outlet CO2

Properties

Oxyfuel Boiler (Flue Gas) Corrosion Environment Trace Element 21


Time

Sca

le

Pilot Plant (Horizontal)

Commercial

Large Scale Demonstration

Oxyfuel system development history in Japan

1990 1993 2011 2015~1998

Pilot Plant (Vertical)

Drop Tube FurnaceIgnition apparatus under Micro-gravity

Callide-A

22


Pilot Plant(Horizontal)

Pilot Plant(vertical)

Demo Plant(Callide)

Capacity Max. 150kg/h(Coal)(1.2MW thermal)

30MWe(100MWth)

Furnace I.D. 1.3m x L 7.5m Actual Furnace

Year 1993 1998 2011

Photo

Pilot plant and demo plant

23


Coal jet ignitionChemistryBurner aerodynamics and heat transfer

Char burnoutSOx

Ash partitioningDeposition Trace elements

Combustion by-productsNOx, SOx

Heat transferRadiant zoneConvective zone

Basic Study Items

24


The first oxyfuel combustion trial in 1993

Air (Wind-box O2: 21%)

Oxyfuel (Wind-box O2: 21%)

Oxyfuel (Wind-box O2: 30%)

Initial Combustion Test

Difficult of holding the stable flame in case of wind-box O2 of 21% in oxyfuel

25

Need to increase the inlet-O2 in order to keep the stable flame and radiation heat transfer

Distance from burner exit [m]

Fla

me

Tem

p. [d

egC

]


Fla

me

Tem

p. [d

egC

]


Fla

me

Tem

p. [d

egC

]

< NEDO Report, 1993 > 25


Flame Propagation Velocity in High CO2 Concentration

In CO2/O2, flame brightness reduces and flame becomes unstable. Flame propagation velocity in CO2/O2 largely decrease to 1/3–1/5 of that in N2/O2

Flame Behavior

0 1 2 3 4

Coal A(N2/O2)

Coal B(N2/O2)

Coal C(N2/O2)

Coal A(CO2/O2)

Coal C(CO2/O2)

Coal concentration　[kg/m3]

Coal C CO2/O

2

Coal C N2/O

2

Coal A N2/O

2

Coal A CO2/O

2

0

0.5

1.0

1.5

Result of gravity-free experiment

30mm

Ignition

5ms

10ms

15ms

20ms

Coal A, N2/O2

Bright Low light

Coal C, N2/O2 Coal C, CO2/O2

< Suda & Okazaki, FUEL, 2007 >

26


One-Dimensional Flame Propagation Model

Δl x

Ignition source

Tw Radiation

Absorption by gas or particle

Scattering by particle

Tp(n) Tg(n)

Heat conduction betweengas and particle

x=L=N×Δl

n=N Flame position Tp(n)>Tig

Volatile releaseand combustion

Element n=1

One-Dimensional Model0

0.5

1

1.5

2

2.5

3

3.5

0 0.5 1 1.5 2 2.5 3 3.5

N2/O2CO2/O2CO2/O2,k=0

Coal concentration [kg/m3]

Calculated Results of Flame Propagation Velocity

Large decrease of flame propagation velocity is mainly due to large heat capacity and small thermal diffusivity in CO2/O2

< Suda & Okazaki, FUEL, 2007 >

In N2/O2

In CO2/O2

27


CaCO3

Easy and efficient CO2

separation · recovery

Small amount ofexhausted flue gas(Extremely low NOx,SOx)

Recycled gas (Mainly CO2 including NOx, SOx)

CoalO2

High concen-tration CO2

Furnace

Recycled heat



Intensify coal combustionDecrease NO further through combustion with low O2 concentrationImprove fuel flexibilityBroaden load change range of a boiler

Additional merits

Schematic of O2/CO2 Coal Combustion with both mass and heat recirculation

SOx emissions)

CaCO3



Small amount ofexhausted flue gas(Extremely low NOx,SOx)

Recycled gas (Mainly CO2 including NOx, SOx)

CoalO2

High concen-tration CO2

Furnace

Recycled heat



Intensify coal combustionDecrease NO further through combustion with low O2 concentrationImprove fuel flexibilityBroaden load change range of a boiler

Additional meritsIntensify coal combustionDecrease NO further through combustion with low O2 concentrationImprove fuel flexibilityBroaden load change range of a boiler

Additional merits

Schematic of O2/CO2 Coal Combustion with both mass and heat recirculationSchematic of O2/CO2 Coal Combustion with both mass and heat recirculation

SOx emissions)

<Liu & Okazaki, FUEL, 2003>

Further NOx Reduction by Heat Recirculation

28


Base case

Oxy-fuelO2 : 30%H.R.: 0%



ConventionalO2 : 21%H.R.: 0%

<Liu & Okazaki, FUEL, 2003>

Drastic Reduction of CR* (Fuel-N to NOx) by Oxy-firing

29


Air

Air Oxy1 Oxy2 Oxy3

Total gas flow 142t/h 117t/h 140t/h 170t/h

Total O2 conc. 21% 30.2% 26.5% 21.7%

FEGT Base Lower Nearly equal Higher

Heat absorption Base Lower Nearly equal Higher

Oxy 1 Oxy 2 Oxy 3

30

40

50

60

70

20 25 30 35Fur

nace

hea

t abs

orp

tion

(MW

)

O2 content of total gas (wetvol%)

Air caseOxy case

WB O2: 30wet%

WB O2: 40wet%

WB O2: 50wet%

Left Front Right Rear Left Front Right Rear Left Front Right Rear Left Front Right Rear

Simulation results suggests that about 27% of total O2 concentration seems to be the same heat absorption in furnace as air combustion

Need to be the same furnace heat absorption in case of retrofit from air combustion boiler

Simulation of heat absorption

< NEDO Report, 2005 >

30


Flame temperatureHeat flux

Same level with heat flux at air in case of 27% total O2 Concentration Flame temperature was 50 degree C lower than that of air

900

1000

1100

1200

1300

1400

1500

1600

1700

1800

0 1 2 3 4 5 6

Fla

me

tem

p. (

deg

ree

C.)

Distance from burner throat (m)

Coal B/Oxy

Coal B/Air

Total O2 Conc. : 27%(wet)

0

50

100

0:00 0:10 0:20 0:30 0:40 0:50 1:00

Hea

t Flu

x

Time

Oxy

Air

Heat flux and Flame temperature (Pilot plant)

< CCSD Report, 2006 >

31


Combustion Characteristics (IHI pilot plant)NOx behavior

32


T. Fujimori (IHI), 34th Int. Symp. On Combustion, Warsaw, August, 2012 33


Combustion Characteristics (IHI pilot plant)Carbon in ash

34


0

5

10

15

20

0 5 10 15 20

SO

3, O

xy m

ode

(ppm

)

SO3 , Air mode(ppm)

Coal A

Coal B

Coal C

0

500

1000

1500

2000

0 500 1000 1500 2000

SO

2, O

xy m

ode

(ppm

)

SO2 , Air mode(ppm)

Coal A

Coal B

Coal C

SO2 SO3

SOx concentration is higher than in air combustion due to recycle

*Negative Pressure in Furnace < CCSD Report, 2006 >

Combustion Characteristics (IHI pilot plant)SOx behavior (1)

35


Combustion Characteristics (IHI pilot plant)SOx behavior (2)

: 3 times of the air

36


‐Oxyfuel Hg‐

0

0.5

1

AH inlet(450degC)

AH outlet(200degC)

BF inlet(170degC)

BF outlet(120degC)

Hg

(-)

Gas sampling point (Gas Temp.)

Hg2+

Hg0

Dust

0

0.5

1

AH inlet(450degC)

AH outlet(200degC)

BF inlet(170degC)

BF outlet(120degC)

Hg

(-)

Gas sampling point (Gas Temp.)

Hg2+

Hg0

Dust

Gas(Air) Gas(Oxy)

Hg behavior in Oxyfuel was almost the same as Air combustion

Behavior of Trace Elements (Mercury)

< Gotou et al., ICOPE-11 , 2011> 37


Large difference in char formation

(in N2) (in CO2)



Operation load

100% 100% 80%

Nozzle type Type1(Initial)

Type2(Optimum)

Type2(Optimum)

O2 conc. on the duct wall[%](Max.)

O2 conc. at the wind-box inlet [%](Max.-Min.)

*Type of injection nozzle is optimized.

(98%) (34%) (34%)

O2 conc. & temp. on the duct wall O2 distribution at the inlet of burner wind-box (Optimization of O2 nozzle)

(3.3%) (1.3%) (0.7%)

*

*

O2 mixing with Recycled flue gas

39


Callide Oxyfuel Project



Callide Oxyfuel Project - Schedule

41


Callide Oxyfuel Project – Engineering



Callide Oxyfuel Project - Retrofit



Callide Oxyfuel Project – ASU & CPU Layout



BTG (Blue)

CO2 capture unit(Green)

ASU (Pink) Improvement the power consumption

for ASU & CO2 capture unit Compactification or downsizing of

ASU & CO2 capture unit

Items Cost [billion JPY]

AuxiliaryPower [MW]

Additional Area [m2]

Boiler retrofit 110 30 -

ASU 295 115 21,000

CO2 capture 205 140 17,000

ASU 2 x 500,000 m3N/h

BTG 600/620 degC USC

CPU 770 t/h

Efficiency Base [air case]

Oxyfuelretrofit case

Gross efficiency [%] 44.2 46.0

Net efficiency [%] 42.0 33.4

Feasiblity Study

< NEDO Report, 2011 >

1000MWe retrofit study in Japan

Study Result

Plant Specification

45


Thermal Efficiency of 1000 Mwe power Plant

46


Future Study

ASU (Air Separation Unit)

BTG (Boiler, Turbine, Generator)

CPU (CO2 Compression and Purification Unit)

Upgrading basic model for simulation

System integration

47


Heat transfer sub-modelRadiant zoneConvective zone

Ccal jet ignition sub-modelChemistryBurner aerodynamics and heat transfer

Char burnout sub-modelSOx

Ash partitioning sub-modelDeposition Trace elements

Combustion by-productsNOx, SOx, Hg

Integrated furnace model

Needed Sub-Models for Oxy-PC Furnace

< J.O.L. Wendt, 2007 AIChE Meeting >48


The oxyfuel R&D and feasibility study were performed from the beginning of 1990’s for national program in Japan, and fundamental data was obtained.Oxyfuel demonstration project is in progress

and operation started in March, 2012.Future activities are in study, and we

progress toward commercialization and future oxyfuel combustion system

Concluding Remarks

49


[Acknowledgements]These studies for the demonstration project were supported by METI, NEDO, JCOAL, J-Power and IHI.

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The Relevance of Oxy-fuel Technology for Japan...0 0.5 1 1.5 2 2.5 3 3.5 N2/O2 CO2/O2 CO2/O2,k=0...

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