Recent research on combustion and NOx emission control at Donghua University

2016/6/16

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Recent research on combustion and NOx reduction at Donghua University

Dr. Prof. Yaxin Su

School of Environmental Science and Engineering,

Donghua University

2016.6.24

Report at Institute of Chemical Processing of Coal, Poland, 2016.6.24

1. Introduction

Before going to the academic topics, I’d like to show you where Donghua University locates and what Donghua looks like.

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1.1 Location of Shanghai in China

Qinlin Moutains-Huaihe River

Changjiang River

1.2a City view of Shanghai

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1.2b City view of Shanghai

492m,2008

632m,2016.3.12

420.5m,1999

1.2c City view of Shanghai

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1.2d City view of Shanghai

The 1st maglev train in the world

Max Speed:430 km/h,

Length: 29.863 km

Run since 2002.12.31

From Pudong International airport to the Metro Line 2 at Longyang Road

1.3 Some basic data of Shanghai

Shanghai covers about 6340 km2 with a population 24.1527 millions (2015)

GDP per capita is 103100 CNY, about 14900 US $( 2015)

Human Development Index is 0.9

Metro line: 617km

2 Airport, 3 main railway stations and 6 minor railway stations

GDP: No. 1 in China and No. 2 in Asia (2014)

Shanghai port cargo handling capacity and container throughput : No. 1 in the world in 2014

41 universities and 25 colleges

59 Institutions authorized to provide graduate degrees (MS, PhD)

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1.4 Location of Donghua University in Shanghai

PVG airport

1.4a Yan’an Road campusMetro

Line 3/4NorthNorth

Entrance

Our school before 2005

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1.4b Pictures of Yan’an Road Campus

1.4c Songjiang Campus ( School of ES&E)

North

East Entrance

North Entrance

School of ES&E

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1.4d Pictures of Songjiang Campus

1.5 History of Donghua University

Donghua University (DHU was founded in 1951,known firstly as East China Institute of Textile Technology , then China Textile University (1985-), then Donghua University (1999-)

DHU is now a multi-disciplinary university, including engineering, economics, management, literature and art, laws, science, and education.

12 colleges and schools, offering 54 undergraduate programs, 59 master’s degree programs, 30 doctoral degree programs.

more than 2,800 faculty and staff,

and over 30,000 enrolled students, among which about 4000 oversea students and 6000 graduate students.

Top 1 in the field of textile, fiber materials and fashion in China and comprehensively ranked the 50th among all the universities in China.

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History of Donghua University

Back

A video by an International student—Shanghai in my eyes

http://english.dhu.edu.cn/_s126/7b/dd/c5178a97245/page.psp

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2. Combustion related research: Completed and going-on

CFB combustion Desulfur, deNOx model in furnace; Heat transfer in furnace; Cyclone separator;

HiTAC( High Temperature Air Combustion) Multi-jet burners; Swirling burners;

NOx reduction by reburning

Mixed fuels based on common wastes, e.g., tires, biomass and lignite ash, biomass ash and iron oxides;

by HC, like CH4,C2H6,C3H8,etc, over iron/iron oxides by HC over iron-based supported catalysts

CO2 capture Sludge pyrolysis and combustion

2.1.1 High Temperature Air Combustion (HiTAC)

Also known as MILD(Moderate and Intensive Low-oxygen Dilution), Flameless Oxidation – FLOX

Advantages: Significantly increased thermal efficiency by recovering the heat

from exhaust flue gases with regenerative system to preheat the combsution air to , e.g., above 1000 C;

Very low NO emission by controlling the O2 in preheated air, e.g., as low as 2%-5 vol. %;

methods of realization of HiTAC Burners- the most important device;

Support combustion with low O2

Regenerative system: ceramic honeycomb Recover waste heat from flue gas

For industrial application and furnace design, the jet parameters and burner configuration are very critical for a good combustion in the furnace.

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2.1.2 Burners of HiTAC

Basically, two types of burners used in industrya. the combustion air is provided by a central, strong (high-momentum)

air jet that is surrounded by a number of weak (low-momentum) fuel jets (in industrial applications typically two jets are used).

b. a central fuel jet and a number of air jets positioned in the relative vicinity of the central fuel jet—recognized in the literature as a “classical” method of achieving flameless combustion

Fuel jet

Preheated air jet

2.1.3 Burners developed in our lab

Multi-jets burner

Swirling burner

furnace

Swirling burner

fuel

air

air

fuel

Multi-jets burners

one circular fuel jet in the center surrounded by 5 circular air jets distributed equably according to the air straddle angle, , an inclined angle of the fuel jet,

D

L

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2.1.4 Numerical simulation based CFD- Multi-jets burners gas combustion:

standard k- model + -PDF combustion model;

Radiation:

Discrete Ordinates method;

NOx model:

thermal + prompt NOx model;

Code: FLUENT

Local O2 ,Temperature and NO field in the furnace (Tair=1273K, Tfuel=300K, =30, =120 , L/D=2.5, vf/vair=1.18, O2=10%,15%, 21% )

8 10 12 14 16 18 20 220

50

100

150

200

250

300

350

Tair

=1273K, Tfuel

=300K

=30o, =120

o

vf/v

air=1.18, L/D=2.5

NO

x e

mis

sio

n /

pp

m

O2 fraction in preheated air / %

2.0 2.2 2.4 2.6 2.8 3.0

40

50

60

70

80

90

100T

air=1273K, T

fuel=300K

=30o, =120

o

O2=15%, v

f/v

air=1.18

NO

em

issi

on /

ppm

L/D

air

fuel

Multi-jets burners

D

L

2.1.5 Numerical simulation based CFD-swirling burners

gas combustion:

Reynolds Stress model + -PDF combustion model;

Radiation:

Discrete Ordinates method;

NOx model:

thermal + prompt NOx model;

Code: FLUENT

Direction injection burner

Swirling burner

Flow vector temperature O2 distribution NO distribution

Air inlet Max. Temp.

(K)

Avg. Temp.

(K)CO molar

fraction(ppm)NO molar

fraction(ppm)

Direct injection (=0) 1876 1575 372 35.2

Swirling (=180) 1914 1633 29 12.3

Swirling burner results to better combustion: better mixing of fuel and air, lower local O2 concentration and thus lower local NO formation, better burnout of fuel and higher temperature in the furnace.

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2.1.6 Papers and patents on HTAC

2 China patents authorized;

10 Chinese Journal papers;

12 International Conference proceeding papers;

2.2 NOx reduction

Typical NO reduction methods

Post-combustion

Selective catalytic reduction (SCR)

Selective non-catalytic reduction (SNCR)

Reducing agent: NH3

Efficiency high, but expensive

Combustion

modification

Low excess air: OFA

Low NOX burner (LNB)

Flue gas re-circulation (FGR)

Efficiency low

Reburning <60%Because of HCN/NH3(coal, NG)

Char-N (coal)

reduced by Fe2O3

Catalyst (e.g., V2O5TiO2) +reducing agent (NH3)

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2.2 our recent work on NOx reduction

We did the following researches on NO reduction since 2010. by reburning

Mixed fuels based on common wastes, e.g., tires, biomass and lignite ash, biomass ash and iron oxides;

by HC, e.g., CH4,C2H6,C3H8,etc, over iron/iron oxides by HC over iron-based supported catalysts

2.2.1 Background of Reburning

“In-Furnace-Control” of NOX:

- Create a fuel rich zone/stage.

- Chemically reduce the NO to N2.

Discovered in 1973 in the US.

First used in Japan in 1983 – 50% reduction in NO realized.

First used in China in 2001– also 50% reduction in NO realized.

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2.2.2a Natural Gas Reburning

C-, CH- and CH2-, effectively reduce NO to HCN, then HCN to N2 via extended Zelidovich mechanism

A problem is that HCN oxidizes to NO in the burnout zone,

Thus, there is a 60% NO reduction floor.

2.2.2b Coal Reburning

Char is the major reaction intermediate which contains nitrogen,

Char nitrogen oxidizes to NO in the burnout zone,

Thus, there is also a 60%NO reduction floor.

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2.2.3 Previous Results

Use of Lignite Fly Ash to Reduce HCN during Methane Reburning

Bag-house ashes are more effective at HCN reduction than those from an electrostatic precipitator, they are also effective at NH3 reduction.

W-YChen and B B Gathitu, Fuel, 2009, 85:1781-1793

2.2.4a Drawbacks of using Lignite Fly Ash for HCN Reduction

The amounts of fly ash required are impractical (720 metric tons per day for a 172 MW coal-fired utility boiler).

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2.2.4b Substitutes Lignite Fly Ash

Substitute for lignite fly ash: Required quantities should be reasonable.

It should not impact boiler performance adversely i.e. slagging and fouling.

Iron oxides selected as lignite fly ash substitute after critical review of literature.

2.2.5 NOx reduction by mixed fuels Reburning

We proposed mixed fuels based on several widely available wastes and demonstrated a NO reduction efficiency of more than 85% after burnout, which made it more competitive than currently preferred technologies such as SCR.

The major contribution is that a method to control reburning intermediates, HCN/NH3 was recognized.

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2.2.5 Effectiveness of Fe2O3 at HCN Reduction

Due to long residence time in our reactor, HCN thermal decomposes.

Fe2O3 effectively converts HCN over a wide range of temperatures.

HCN Concentration in Helium = 600 ppm

Fe Concentration = 1200 ppm

Residence Time = 0.2 sec

0

50

100

150

200

250

300

350

1100 1150 1200 1250 1300 1350

Furnace Temperature (°C)

Exit

HC

N (

pp

m)

HCN Yields Without Fe2O3 HCN Yields With Fe2O3

Su, Y X, et al, Fuel, 2010, 89:2569-2582

2.2.6 Mechanism of HCN reduction by Fe2O3

Fe2O3+3CO2Fe+3CO2

2Fe+3NOFe2O3+1.5N2

2Fe2O3+3HCN4Fe+3CO+3NO+1.5H2

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2.2.7 Effects of Water and Temperature during Reburning and Burnout with Fe2O3

Presence of water vapor and high temperatures enhance its activity. Temperature of 1250 °C is selected because thermal decomposition is minimal

and activity of Fe2O3 present Water concentration of 6.35% selected – typical to that in coal-fired boilers.

SR2 = 0.85, SR3 = 1.1

Feed NO = 500ppmBurnout Furnace Temperature = 1150 °C

45%

50%

55%

60%

65%

70%

75%

80%

0 1000 2000 3000 4000 5000

Fe Concentration (ppm)

No

min

al

NO

Red

ucti

on

(%

)

1250 °C (without water) 1250 °C (with 6.35% water)

1250 °C (with 17% water) 1150 °C (with 6.35% water)

Su, Y X, et al, Fuel, 2010, 89:2569-2582

2.2.8a NO Reduction by Mixed Reburning Fuels

With a temperature and water concentration selected, other fuels were tested at optimal SR2 for NO reduction and optimal SR3 to achieve burnout

Feed NO = 500ppm

Furnace Temperatures: Reburn = 1250 °C, Burnout = 1150 °C

40%

45%

50%

55%

60%

65%

70%

75%

80%

85%

90%

0 1000 2000 3000 4000 5000 6000 7000 8000


No

min

al

NO

Red

ucti

on

(%

)

Chinese Tire (SR2 = 0.9, SR3 = 1.2) Pine Bark SR2 = 0.9, SR3 = 1.3)Corn Stover Residue (SR2 = 0.9, SR3 = 1.25) Sludge (SR2 = 0.95, SR3 = 1.3)Wood Fines (SR2 = 0.9, SR3 = 1.3) US Tire (SR2 = 0.9, SR3 = 1.2)Methane (SR2 = 0.9, SR3 = 1.1)

A combination of material A and F form an excellent substitute for natural gas and lignite ash.

Up to 88% NO reduction possible at 4000ppm of Fe2O3 (185 metric tons per day for a 172 MW coal-fired boiler –compared to 720 metric tons of lignite fly ash)

Char-N conversion to NO in the burnout zone limits the other fuels.

Fe2O3 does not cause fouling or slagging in the boiler.

Su, Y X, et al, Fuel, 2010, 89:2569-2582

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2.2.8b NO Reduction by Mixed Reburning Fuels

Feed NO = 500ppm

Furnace Temperatures: Reburn = 1250 °C, Burnout = 1150 °C

60%

65%

70%

75%

80%

85%

90%

0 1000 2000 3000 4000 5000 6000 7000 8000


No

min

al

NO

Re

du

cti

on

(%

)

Chinese Tire with Mill Scale (SR2 = 0.9, SR3 = 1.2) Methane with Mill Scale (SR2 = 0.9, SR3 = 1.1)

Chinese Tire with Sea Nodules (SR2 = 0.9, SR3 = 1.2) Methane with Sea Nodules (SR2 = 0.9, SR3 = 1.1)

Effects of mill scale and sea nodules on NO reduction efficiencies of tire and methane as reburning fuels during two-stage tests.

A mixture of tire and mill scale can achieve up to 82% NO reduction, while tire and sea nodules can achieve 78% NO reduction. Mill scale contains 90 % Fe2O3 while sea nodules contain only 20% Fe2O3 making mill scale the better option.

Su, Y X, et al, Fuel, 2010, 89:2569-2582

At present, there is a great incentive to use natural gas or other hydrocarbons as reductant in stationary SCR units rather than NH3, because of:

In many new power plants, NG is commonly used as fuel and is readily available;

NH3 is more expensive, requires special handling and storage and needs a sophisticated metering system to avoid NH3 slip.

We recently experimentally demonstrated that methane could effectively reduce NO over iron/ iron oxides.

2.3 NOx reduction by iron with HC

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2.3.1 First work on NO reduction by iron

B. Gradon & J. Lasek，Fuel 89 (2010) 3505–3509

NO molar fractions measured in the gas leaving the reactor in function of time: temperature 850 C, gas mixture 1015 ppm NO/N2, four iron samples of surface area 1.2110-3 m2, gas stream 9.54 10-4 mol/s.

Influence of vary oxygen molar fractions in the reacting gas on the NO reduction efficiency at temperature 850 C and average iron surface area1.16 10-3 m2.

Iron ball of diameter of 10mm as iron sample

We continued and improved the work.

2.3.2 our further work--Experimental setup

Length

Wid

th

6mm6mm

Iron mesh Mesh roll

Fig. 2 Iron mesh roll

Iron mesh roll

Electrically heat furnace

Reactor tube

Simulated flue gas

To analyzer

Fig 1 Experimental setup

simulated flue gas consisting 0.05% NO in nitrogen base,flow rate:1.5 L/min

ceramic tube of inner diameter of 2.5 cm

online analyzer (ECOM-J2KN, Germany)

iron mesh size160mm×80mm

80mm×80mm

160mm×40mm

Reacting time0.13s0.13s0.06s

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2.3.3 Results and discussion

2.1 Reduction of NO by iron.

20

40

60

80

100

300 600 900 1200

temperature (°C)

Eff

icie

ncy

(%

)

160mm x 80mm

80mm x 80mm

160mm x 40mm

Reacting time0.13s0.13s0.06s

4 0 5 0 6 0 7 0 8 0 9 00

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

T w o - T h e ta ( d e g )

F e

F e ,N i

XRD results of the original iron

XRD results of the iron after reaction with NOin N2 atmosphere (1100 C)

3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 1 2 00

5 0 0

1 0 0 0

1 5 0 0

2 0 0 0

2 5 0 0

T w o -T h e ta ( d e g )

F e

F e + 2 F e 2 + 3 O 4

F e 2 O 3

2x yFe NO Fe O N


2.3.3.1 Reduction of NO by iron

0 10 20 30 40 50 60 70

20

40

60

80

100

NO

red

ucti

on /

%

durable time /hr

durable reduction of NO by metallic iron in N2 atmosphere (flow rate 1.5L/min, NO=0.05in N2 base at 800 C)

10 20 30 40 50 60 70 80 900

500

1000

1500

2000

Fe2O3

Fe+2

Fe2+3

O4

Inte

nsit

y(C

PS

)

2()

XRD pattern of iron oxides after durable reaction

Fe could reduce NO to N2, while it is oxidized to FexOy( finally Fe2O3), resulting to decreased NO reduction. Therefore, a reducing agent should be added to reduce iron oxides to iron in order to keep the reaction. CO and CH4 were used as reducing agents and NO reduction was tested respectively in simulated flue gas. The iron oxides after the above durable test was used as iron oxides in the following test.

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2. 3.3.2 Reduction of NO by iron + CO/CH4

0

20

40

60

80

100

0 20 40 60 80 100

durable t ime, hr

NO

red

uct

ion

, %

stop CO and feed 1.17% CH4

Durable reaction of NO reduction by CO/CH4 over iron oxides in simulated flue gas (O2: 2.0%, CO2: 16.8%, NO: 524ppm in N2

base) at 1000 C

10 20 30 40 50 60 70 80 900

500

1000

1500

2000

2500

3000

3500

FeO

+ Fe+2

Fe2

+3O4

+

+

++++

++

++

++

+Inte

nsit

y(C

PS

)

2()

+

XRD pattern of iron oxides after durable reaction with CH4 and NO at 1000 C

Very good NO reduction when CH4 was used as reducing agent over iron oxides. Iron oxides( Fe2O3) was partly reduced ( Fe3+ Fe2+)

Further test was conducted in N2 atmosphere to find out the mechanism.

2.3.3 Results and discussion 2.3.3.2 Reduction of NO by CH4 over iron oxides

2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 1 0 0 0 1 1 0 00

2 0

4 0

6 0

8 0

1 0 0

NO reduction/

%

T e m p e r a t u r e /℃

NO reduction by methane over iron oxides (flow rate 1.5L/min, CH4=1.17%, NO=0.05% in N2 base)

2 00 300 400 50 0 600 7 00 80 0 900 1 000 11000

100 0

200 0

300 0

400 0

500 0

600 0

Exit

CO

/ p

pm

Temperature/℃

C H4=1.17%

CO formation (flow rate 1.5L/min, CH4=1.17%, NO=0.05% in N2 base)

10 20 30 40 50 60 70 80 90

0

200

400

600

800

1000

6

88

6

8

6

8

8

8 FeO

6 FeFe2O3

Fe+2

Fe2

+3O4

Inte

nsit

y(C

PS

)

2()

XRD pattern of iron oxides after reaction (flow rate 1.5L/min, CH4=1.17%, NO=0.05% in N2 base, 1050C)

SEM image of iron oxides after reaction (flow rate 1.5L/min, CH4=1.17%, NO=0.05% in N2 base, 1050C)

CO formed

Iron oxides reduced to iron

Carbon formed

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2.3.3 Results and discussion 2.3.3.3 mechanism of NO reduction by methane over iron oxides

The mechanism was rather complex and includes the following paths:

NO reduction by methane via reburning

Iron oxides reduction to iron by methane

NO reduction by iron


NO reduction by methane via reburning

In fuel rich conditions, methane could reduce NO through reburning mechanism with the following basic route

HCNNOCH i （R1）

Then HCN was reduced to N2 according to the extended reverse Zeldovich reactions:

HNCO OHCN

CONHHNCO

2HN HNH

ON NON 2

(R2)

(R3)

(R4)

(R5)

Fe2O3 could reduce HCN:

2 3 2 23 2 3 1.5 1.5Fe O HCN Fe CO N H R(6)

Discussion:

Reburning needs O radical, as showed in (R2). Iron oxides could provide lattice oxygen to make reburning happen. However, in N2 atmosphere, O radical provided by iron oxides is not enough to make reburning the dominant mechanism. However, in real condition where there is O2 in the flue gas, reburning happens.

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-600

-500

-400

-300

-200

-100

0

100

200

300

300 500 700 900

Temperature/ oC

△G

R10 R11 R12

R13 R14 R15

2.3.3.3 mechanism of NO reduction by methane over iron oxides


The lattice oxygen provided by iron oxides (Fe2O3 and Fe3O4) at high temperature could partially oxidize methane to

CO/CO2 and the iron oxides would be reduced to metallic iron at the same time by methane above 570 C according to

the sequence Fe2O3 Fe3O4 FeOFe.

Main reactions:

2 3 4 3 4 23 ( ) 2 ( ) 2 ( )Fe O CH g Fe O CO g H g

3 4 4 2( ) 3 ( ) 2 ( )Fe O CH g FeO CO g H g

4 2( ) ( ) 2 ( )FeO CH g Fe CO g H g

(R10)

(R(11)

(R12)

Secondary reactions:

2 3 4 3 4 2 212 ( ) 8 ( ) 2 ( )Fe O CH g Fe O CO g H O g

3 4 4 2 24 ( ) 12 ( ) 2 ( )Fe O CH g FeO CO g H O g

4 2 24 ( ) 4 ( ) 2 ( )FeO CH g Fe CO g H O g

(R13)

(R(14)

(R15)

100

150

200

250

300

350

400

450

500

300 500 700 900

Temperature/ oC

△H

R10 R11 R12

R13 R14 R15

changes of the thermodynamics Gibbs free energy, G, and the reaction heat, H

1

2

3

CO formed during the reaction of iron oxides with methane. CO /H2 will further react with iron oxides and reduce iron oxides to iron.

In addition, methane will decompose to C and H2 at high temperature:



4 2( ) 2 ( )CH g C H g

The cracking reaction of methane begins at 550C, but it goes on very slowly at 600-850 C and no more than 3.4% methane could decompose below 850C .

The carbon due to the decomposition of methane was very active and reacted with iron oxides immediately to reduce iron oxides to metallic iron :

2 3 21.5 2 1.5Fe O C Fe CO

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NO reduction by iron

2 3 22 3 1.5Fe NO Fe O N

Since iron oxides will be reduced to iron by methane during the reaction and then iron will reduce NO to N2 while iron will be oxidized to iron oxides, the NO reductions will be the same whether iron or iron oxides is used when methane is the reductant.

2.3.3.4 NO reduction by methane over iron oxides in flue gas atmosphere


1

2

3

7

3 8

456

Experimental setup1: gas sources; 2-flow meter; 3- ceramic tube; 4: iron/iron oxides roll; 5-

electrically heated furnace; 6- secondary oxygen input; 7- electrically heated furnace; 8-flue gas analyzer

Simulated flue gas:1.5L/min, 0.05 vol. % NO, 2.0 vol. % O2, 17.0 vol. % CO2 in N2 base

methane: controlled by stoichiometric ratio (SR)

SR : the ratio of actual oxygen in the flue gas and the oxygen that complete combustion of methane requires.

SR1: redurning

SR2: burnout

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300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

ucti

on /

%temperature /

oC

without Fe2O

3, SR

1=0.7, SR

2=0.7

with Fe2O

3, SR

1=0.7, SR

2=0.7

without Fe2O

3, SR

1=0.7, SR

2=1.2

with Fe2O

3, SR

1=0.7, SR

2=1.2

without Fe2O

3, SR

1=1.0, SR

2=1.0

with Fe2O

3, SR

1=1.0, SR

2=1.0

without Fe2O

3, SR

1=1.0, SR

2=1.2

with Fe2O

3, SR

1=1.0, SR

2=1.2

without Fe2O

3, SR

1=1.2, SR

2=1.2

with Fe2O

3, SR

1=1.2, SR

2=1.2

Comparison of NO reduction by methane in simulated flue gas atmosphere when iron oxides was or was not used (flow rate 1.5L/min, O2=2.0 vol. %, NO =0.05 vol. %, CO2=17.0 vol. % in N2 base)

2.3.3.4 NO reduction by methane over iron oxides in flue gas atmosphere

300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

uct

ion /

%

temperature / oC

SR1=0.7, SR

2=0.7

SR1=0.7, SR

2=1.2

SR1=0.8, SR

2=0.8

SR1=0.8, SR

2=1.2

SR1=0.9, SR

2=0.9

SR1=0.9, SR

2=1.2

SR1=1.0, SR

2=1.0

SR1=1.0, SR

2=1.2

SR1=1.1, SR

2=1.1

SR1=1.1, SR

2=1.2

SR1=1.2

NO reduction by methane over iron oxides in simulated flue gas atmosphere (flow rate 1.5L/min, O2=2.0 vol. %, NO =0.05 vol. %, CO2=17.0 vol. % in N2 base)

200 400 600 800 1000 1200

0

20

40

60

80

100

NO

red

uct

ion

/%

Temperature/oC

CH4=0.2%

CH4=0.4%

CH4=0.8%

CH4=1.0%

CH4=1.17%, Fe

2O

3

NO reduction by methane over iron in N2 atmosphere

300 450 600 750 900 10500

1000

2000

3000

4000

5000

exit

CO

/ p

pm

temperature / oC

CH4=0.2%

CH4=0.4%

CH4=0.8%

CH4=1.0%

Exit CO when methane reducing NO over iron in N2 atmosphere

Results showed the same results when iron/iron oxides was used.

2.3.3.5 NO reduction by methane over iron

NO reduction by methane over iron in N2 atmosphere


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2.3.3 Results and discussion 2.3.3.5 NO reduction by methane over iron

NO reduction by methane over iron in simulated flue gas atmosphere

300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

uct

ion

/ %

temperature / oC

SR1=0.7, SR

2=0.7

SR1=0.7, SR

2=1.2

SR1=0.8, SR

2=0.8

SR1=0.8, SR

2=1.2

SR1=0.9, SR

2=0.9

SR1=0.9, SR

2=1.2

SR1=1.0, SR

2=1.0

SR1=1.0, SR

2=1.2

SR1=1.1, SR

2=1.1

SR1=1.1, SR

2=1.2

SR1=1.2

NO reduction by methane over metallic iron in simulated flue gas atmosphere (flow rate 1.5L/min, O2=2.0 vol. %, NO =0.05 vol. %, CO2=17.0 vol. % in N2 base)

300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

ucti

on /

%

temperature / oC

without iron, SR1=0.7, SR

2=0.7


2=1.2

with iron, SR1=0.7, SR

2=0.7


2=1.2


2=1.0


2=1.2


2=1.0


2=1.2


2=1.2


2=1.2

Comparison of NO reduction by methane in simulated flue gas atmosphere when iron was or was not used(flow rate 1.5L/min, O2=2.0 vol. %, NO =0.05 vol. %, CO2=17.0 vol. % in N2 base)


300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

ucti

on /

%

temperature / oC

iron, SR1=0.7, SR

2=0.7

iron, SR1=0.7, SR

2=1.2

iron oxides, SR1=0.7, SR

2=0.7


2=1.2

iron, SR1=1.0, SR

2=1.0

iron, SR1=1.0, SR

2=1.2


2=1.0


2=1.2

iron, SR1=1.2

iron oxides, SR1=1.2

Comparison of NO reduction by methane over metallic iron and iron oxides

(flow rate 1.5L/min, O2=2.0 vol. %, NO =0.05 vol. %, CO2=17.0 vol. % in N2 base)

2.3.3.5 NO reduction by methane over iron

Comparison between NO reduction by methane over iron and iron oxides in simulated flue gas atmosphere

Yaxin Su, et al. Fuel, 2015, 160: 80-86

2016/6/16

28

2.3.3 Results and discussion 2.3.3.6 Effect of SO2 on NO reduction by iron in N2 base

200 400 600 800 10000

20

40

60

80

100

NO

red

ucti

on /

%

Tempereture / oC

SO2=0.01%

SO2=0.02%

SO2=0.04%

Effect of SO2 on NO reduction over metallic iron in N2 atmosphere (flow

rate 1.5L/min, NO=0.05%, SO2=0.01%-0.04% in N2 base)

200 400 600 800 10000

20

40

60

80

100

SO

2 re

duct

ion

/ %

Tempereture / oC

SO2=0.01%

SO2=0.02%

SO2=0.04%

SO2 reduction during the reaction of NO with iron (flow rate

1.5L/min, NO=0.05%, SO2=0.01%-0.04% in N2 base)

10 20 30 40 50 60 70 80 900

100

200

300

400

500

600

700

800

2 / o

Inte

nsit

y(C

PS

)

FeOFeS

* Fe

XRD pattern of iron sample after reducing NO in N2 atmosphere when

SO2=0.04% (flow rate 1.5L/min, NO=0.05%, SO2=0.04% in N2 base,

1050C)

2.3.3 Results and discussion 2.3.3.6 Effect of SO2 on NO reduction by iron in N2 base

0 10 20 30 40 50 60 70

20

40

60

80

100

NO

reducti

on /

%

durable time /hr

SO2=0.022%

SO2=0

Effect of SO2 on durable reduction of NO by metallic iron in N2 atmosphere at 800 C

(flow rate 1.5L/min, NO=0.05%, SO2=0/0.022% in N2 base, 800 C)

10 20 30 40 50 60 70 80 90

0

500

1000

1500

2000

Fe2O

3

Fe+2

Fe2

+3O

4

Inte

nsit

y(C

PS

)

2 / o

(a) SO2=0

10 20 30 40 50 60 70 80 900

1000

2000

3000

4000

5000

6000

Fe2O3

Inte

nsit

y(C

PS

)

2 / o

(b) SO2=0.022%

2016/6/16

29


200 400 600 800 10000

20

40

60

80

100

NO

red

ucti

on /

%

Temperature / oC

SO2=0.01%, CH

4=0.4%

SO2=0.04%, CH

4=0.4%

SO2=0.01%,CH

4=0

SO2=0.04%, CH

4=0

Effect of SO2 on NO reduction by methane over metallic iron in N2 atmosphere (flow rate

1.5L/min, NO=0.05%, SO2=0.01%/0.04%, CH4=0.4% in N2 base)

2.3.3.7 Effect of SO2 on NO reduction by methane + iron in N2 base

10 20 30 40 50 60 70 80 900

100

200

300

400

500

600

700

800

2 / o

Inte

nsit

y(C

PS

)

FeOFeS

* Fe

XRD pattern of iron sample after reducing (flow rate 1.5L/min, NO=0.05%, SO2=0.04% in

N2 base, 1050C)

10 20 30 40 50 60 70 80 900

100

200

300

400

500

600

700

800

Inte

nsit

y(C

PS

)

2 / o

Fe

Fe+2

Fe2

+3O

4

FeS

XRD pattern of iron sample after reducing NO by methane i (flow rate 1.5L/min, NO=0.05%, SO2=0.04%，CH4=0.4% in N2 base, 1050C)

300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

ucti

on /

%

Temperature / oC

SO2=0, SR

1=0.7,SR

2=0.7

SO2=0, SR

1=0.7,SR

2=1.2

SO2=0.01%,SR

1=0.7,SR

2=0.7

SO2=0.01%,SR

1=0.7,SR

2=1.2

SO2=0.02%,SR

1=0.7,SR

2=0.7

SO2=0.02%,SR

1=0.7,SR

2=1.2

SO2=0.04%,SR

1=0.7,SR

2=0.7

SO2=0.04%,SR

1=0.7,SR

2=1.2

Effect of SO2 on NO reduction by methane over ironin simulated flue gas atmosphere

(flow rate 1.5L/min, O2=2.0%, CO2=16.8%, NO=0.05%, SO2=0.01%~0.04% in N2 base)

2.3.3 Results and discussion 2.3.3.8 Effect of SO2 on NO reduction by methane + iron/iron oxides in

simulated flue gas

300 400 500 600 700 800 900 10000

20

40

60

80

100

NO

red

uct

ion

/ %

Temperature / oC

SO2=0, SR

1=0.7, SR

2=0.7

SO2=0, SR

1=0.7, SR

2=1.2

SO2=0.01%, SR

1=0.7, SR

2=0.7

SO2=0.01%, SR

1=0.7, SR

2=1.2

SO2=0.02%, SR

1=0.7, SR

2=0.7

SO2=0.02%, SR

1=0.7, SR

2=1.2

SO2=0.04%, SR

1=0.7, SR

2=0.7

SO2=0.04%, SR

1=0.7, SR

2=1.2

Effect of SO2 on NO reduction by methane over iron oxides in simulated flue gas atmosphere (flow rate

1.5L/min, O2=2.0%, CO2=16.8%, NO=0.05%, SO2=0.01%~0.04% in N2 base)

2016/6/16

30

2.3.3.9 Effect of SO2 on durable test


0 10 20 30 40 50 60 70 80 90 10050

60

70

80

90

100

NO

red

ucti

on /

%

durable time / hr

Durable reaction of NO reduction by methane over iron oxides in simulated flue gas at 1000 C (flow rate 1.5L/min, NO=0.05%, CO2=16.8%,O2=2.0%, CH4=1.13%，SO2=0.02% in N2 base)

20 40 60 800

200

400

600

800

1000

1200

1400

Fe2O

3

FeO

Fe+2

Fe2

+3O

Inte

nsit

y(C

PS

)

2 / o

XRD pattern of iron oxides after durable reaction with CH4 and NO at 1000 C

Yaxin Su, et al. Fuel, 2016, 170: 9-15


2.3.3.10 Effect of water vapor

300 500 700 900 11000

20

40

60

80

100 H

2O=7%，SR

1=0.7，SR

2=1.2

H2O=7%，SR

1=0.9，SR

2=1.2

H2O=7%，SR

1=1.2，SR

2=1.2

H2O=0%，SR

1=0.7，SR

2=1.2

H2O=0%，SR

1=0.9，SR

2=1.2

H2O=0%，SR

1=1.2，SR

2=1.2

NO

red

uct

ion η

/%

Temperature t /℃

Effect of water vapor on NO reduction with iron by methane in simulated flue gas atmosphere (Flow rate 2L/min, NO=0.05%，O2=2.0%，H2O=7%，CO2=16.8%, CH4 is controlled by excess air ratios)

400 600 800 1000

0

20

40

60

80

100 SR

1=0.7,SR

2=1.2,H

2O=7%,SO

2=0.02%

SR1=0.9,SR

2=1.2,H

2O=7%,SO

2=0.02%

SR1=1.2,SR

2=1.2,H

2O=7%,SO

2=0.02%

SR1=0.7,SR

2=1.2,H

2O=7%,SO

2=0%

SR1=0.9,SR

2=1.2,H

2O=7%,SO

2=0%

SR1=1.2,SR

2=1.2,H

2O=7%,SO

2=0%

NO

red

uct

ion η

/%

Temperature t /℃

Effect of SO2 during the reaction of NO with iron by methane in wet flue gas atmosphere (Flow rate 2L/min, NO=0.05%，O2=2.0%, CO2=16.8%, H2O=7%, SO2=0.02%, CH4 is controlled by excess air ratios in N2 base)

2016/6/16

31


2.3.3.11 Effect of H2O+SO2 on durable test

Durable reaction of NO reduction by methane over iron oxides in simulated flue gas at 1050 C (flow rate 2 L/min, NO = 0.05%, CO2 = 16.8%,O2 = 2.0%, CH4 = 1.14%,H2O = 7%,SO2 = 0.02% in N2 base)

0 10 20 30 40 5050

60

70

80

90

100

NO

red

ucti

on,

/ %

durable time / h

Zhou, Hao, Su, Yaxin*, Qi, Yuezhou, et al. J Fuel Chem Tech ( in Chinese), 2014,42(11): 1378-1386


2.3.3.12 C2H6 reducing NO over Fe

200 300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

ucti

on

C2H

6=0.1%

C2H

6=0.2%

C2H

6=0.3%

without iron, C2H

6=0.1%

CH4=0.1%, [25]

CH4=0.2%, [25]

Temperature / oC

NO reduction by ethane over iron in N2 atmosphereflow rate 2L/min, NO=0.05%, C2H6=0.1%~0.3% in N2 base

20 40 60 800

500

1000

1500

2000

2500

* * * *+

+

++ +

+

+

+

(a) C2H

6=0.1%

+

+ Fe3O

4

* FeO

2()

Inte

nsi

ty (

CP

S)

20 40 60 800

500

1000

1500

2000

2500

+

+

+ ++

##

(b) C2H

6=0.2%

+

#

2()

Inte

nsit

y (C

PS

)

# Fe

+ Fe3O

4

XRD pattern of iron samples after reducing NO in N2 atmosphere when C2H6=0.1%/0.2%

flow rate 2 L/min, NO=0.05%, in N2 base, 1100C

COOHFeHCOFe 691035 26232

226232 691437 COOHFeHCOFe

20 40 60 800

200

400

600

800

1000

1200(a) iron oxides before reaction

** *

#

#

# # #

++

++

+

+

+

*#

+

Inte

nsit

y (

CP

S)

2()

+ Fe3O

4

# Fe2O

3

* FeO

20 40 60 800

500

1000

1500

2000

2500

3000 ( b) after reaction with C2H

6=0.1%

Inte

nsi

ty (

CP

S)

#

#

## Fe

2()

400 600 800 10000

20

40

60

80

100

SR1=0.7，SR

2=1.2，C

2H

6

SR1=0.8，SR

2=1.2，C

2H

6

SR1=0.9，SR

2=1.2，C

2H

6

SR1=1.0，SR

2=1.2，C

2H

6

SR1=1.1，SR

2=1.2，C

2H

6

SR1=1.2，SR

2=1.2，C

2H

6

SR1=0.7，SR

2=1.2，CH

4

SR1=0.8，SR

2=1.2，CH

4

SR1=0.9，SR

2=1.2，CH

4

SR1=1.0，SR

2=1.2，CH

4

SR1=1.1，SR

2=1.2，CH

4

SR1=1.2，SR

2=1.2，CH

4NO

red

ucti

on

/ %

Temperature / oC

Comparison of NO reduction by ethane and methane over iron in simulated flue gas atmosphere flow rate 2L/min, O2=2.0%, CO2=17.0%, NO=0.05%, in

N2 base

DOU Yifeng, SU Yaxin*, et al. J Fuel Chem Tech ( in Chinese), 2015, 43(10):1273-1280

2016/6/16

32



200 300 400 500 600 700 800 900 1000 11000

20

40

60

80

100

NO

red

uct

ion

Temperature / oC

C3H

8 =0.05%

C3H

8 =0.1%

C3H

8 =0.2%

CH4 =0.2%

CH4 =0.4%

NO reduction by propane over iron in N2 atmosphere（flow rate 2L/min, NO=0.05%,C3H8=0.05%-0.2% in

N2 base）

20 40 60 80 1000

500

1000

1500

2000 (a) C3H

8=0.1%，XRD

++

* * * * * * *

* Fe3O

4

+ Fe

Inte

nsi

ty (

CP

S)

/ o

*

+

20 40 60 80 1000

500

1000

1500

2000

2500

3000

(b) C3H

8=0.2%，XRD

/ o

*

*

* * Fe

Inte

nsi

ty (

CP

S)

C3H8=0.1%,SEM

C3H8=0.2%,SEM

300 400 500 600 700 800 900 10000

20

40

60

80

100

?

NO

red

ucti

on

/ %

Temperature / oC

SR1=0.7, SR

2=1.2, C

3H

8

SR1=0.8, SR

2=1.2, C

3H

8

SR1=0.9, SR

2=1.2, C

3H

8

SR1=1.0, SR

2=1.2, C

3H

8

SR1=1.1, SR

2=1.2, C

3H

8

SR1=1.2, SR

2=1.2, C

3H

8

SR1=0.7, SR

2=1.2, CH

4

SR1=0.8, SR

2=1.2, CH

4

SR1=0.9, SR

2=1.2, CH

4

SR1=1.0, SR

2=1.2, CH

4

SR1=1.1, SR

2=1.2, CH

4

SR1=1.2, SR

2=1.2, CH

4

Comparison of NO reduction by propane and methane over metallic iron in simulated flue gas atmosphere (flow rate 2L/min, O2=2.0%, NO=0.05%, CO2=17.0%, in N2

base)

SU, Yaxin, et al. J Fuel Chem Tech ( in Chinese), 2014, 42(12): 1470-1477



400 600 800 1000 12000

20

40

60

80

100 SR

1=SR

2=0.7

SR1=0.7, SR

2=1.2

SR1=SR

2=0.8

SR1=0.8, SR

2=1.2

SR1=SR

2=0.9

SR1=0.9, SR

2=1.2

SR1=SR

2=1.0

SR1=1.0, SR

2=1.2

SR1=SR

2=1.1

SR1=1.1, SR

2=1.2

SR1=SR

2=1.2

NO

red

ucti

on

Temperature / oC

C3H6 reducing NO over Fe (flow rate 2L/min, O2=2.0%, NO=0.05%, CO2=17.0%, in N2 base)

4 00 600 8 00 10 00 120 00

20

40

60

80

1 00

NO

red

uct

ion

/ %

T em p erature / oC

H2O = 7% ,S O

2= 0 .02% , S R

1= 0 .7 , S R

2= 1 .2 H

2O = 7% ,S O

2= 0 ,S R

1= 0 .7 , SR

2=1 .2

H2O = 7% ,S O 2= 0 .02% ,S R

1= 0 .9 , S R

2= 1 .2 H

2O = 7% ,S O

2= 0 ,S R

1= 0 .9 , S R

2= 1 .2

H2O = 7% ,S O

2= 0 .02% ,S R

1= 1 .0 , SR

2=1 .2 H

2O = 7% ,S O

2= 0 ,S R

1= 1 .0 , SR

2=1 .2

H2O = 7% ,S O

2= 0 .02% ,S R

1= S R

2= 1 .2 H

2O = 7% ,S O

2= 0 ,S R

1= S R

2= 1 .2

Effect of SO2 and H2O on C3H6 reducing NO over Fe (flow rate 2L/min, O2=2.0%, NO=0.05%, CO2=17.0%,

H2O=0-7%, SO2=0-0.02%, in N2 base)

LIANG Jun-qing, SU Ya-xin*, et al. J Fuel ChemTech ( in Chinese), 2016 （in press)

2016/6/16

33

Major shortcomings

The reaction happens above 850 C may be a major shortcoming for the application of NO reduction by hydrocarbons. So, it is necessary to try to find a catalystbased on iron which is effective at lower temperature.

Iron-supported catalysts were tested.

2.4 iron based supported catalyst for SCR-HC

2.4.1 Monolithic cordierite-based Fe/Al2O3 catalysts

10 20 30 40 50 60 70 80

SO2-treated catalyst

H2O-treated catalyst

Fresh catalyst

○ 2MgO·2Al2O3·5SiO2

● Fe2O3

Inte

nsit

y /(

CP

S)

2θ /(°)

○

○○

○○ ○

○

○○ ○ ○

○●●

●●

● ●

Fe3+ supported on ceramic honeycomb cordierite by sol/gel- impregnation method and calcined at 500C for 5 h with Fe load 6 wt% (fresh catalyst), The fresh catalysts were exposed to gas stream containing either 10% H2O or 0.02% SO2 at a flow rate of 1500 ml/min at 700C for 24 h and were noted as “H2O-treated” or “SO2-treated” catalyst.

Fe/Al2O3/cordierite

2016/6/16

34


2.4.2 NO reduction with C3H8

(a) 500 ppm NO, 800 ppm C3H8, GHSV =18000 h-1

200 300 400 500 600

0

20

40

60

80

100

NOx

C3H8

Temperature (°C)

NO

x C

onve

rsio

n (%

)

0

20

40

60

80

C3H

8 Conversion (%

)

(a)

200 300 400 500 600 700

0

20

40

60

80

100

NOx

C3H8

Temperature (°C)

NO

x C

onve

rsio

n (%

)

0

20

40

60

80

100

C3H

8 Conversion (%

)

(b)

(b) 500 ppm NO, 0.3% C3H8, 1% O2, GHSV

=18000 h-1

200 300 400 500 600 700

0

20

40

60

80

100

NO

x C

onv

ersi

on (

%)

Temperature (°C)

Fresh catalyst H2O-treated catalyst SO2-treated catalyst


2.4.3 Effect of H2O/SO2

0 2 4 6 8 10 12

0

20

40

60

80

100

550°C

Removing SO2

Reaction tiome t/h

Adding H2O

NO

x C

onv

ersi

on (

%)

Adding SO2 Removing H

2O

600°C

500 ppm NO, 0.3% C3H8, 1% O2, 0.02% SO2 (when used), 2.5% H2O (when used), GHSV =18000 h-1, T = 600 /550℃

2016/6/16

35

2.4.3 DRIFT in situ study-H2O


In situ DRIFTS of NO and C3H8 adsorption over the Fe/Al2O3/ cordierite catalyst at 200 C in the presence of 2.5% H2O.

NO2

adspecies

bidentate nitrate unidentate

acetate

formate

When 2.5%H2O was introduced, NO2 adspeciesdisappeared, bidentate nitrate (1596 cm−1) showed red shift to 1570 cm−1，unidentate (1299cm-1) became weak-H2O disturbed the adsorption

60 min after introducing 2.5%H2O , acetate (1471 cm-1) and formate (1376 cm-1) had no change--the inhibition effect of H2O on acetate/formate species was negligible

When H2O was cut-off, everything almost recovered, which indicated that H2O had a reversible influence on the adsorption on catalyst surface


In situ DRIFTS of NO and C3H8 adsorption over the Fe/Al2O3/cordierite catalyst in the presence of

0.2% SO2.(200℃)

When 0.2% SO2 was introduced, surface nitrate species at1299,1596, 1628 cm-1 decrease in intensity,

unidentate nitrate band (1299 cm-1) completely disappeared after 30 min, sulphate species (1328 cm-1) appeared due to the deposited SO4

2- species

acetate species (1471 cm-1) and formate species (1376 cm-1) increased gradually with time in the presence of SO2.

When SO2 was shut-off, nitrate and acetate/formate species recovered slightly

adsorbed sulphate species still exist，which indicated that SO2 had an irreversible influence on the adsorption on catalyst surface

2.4.4 DRIFT in situ study-SO2

2016/6/16

36

2.4.5 Mechanism


Hao Zhou, Yaxin Su*, Wenyu Liao, et al. Fuel, 2016, 182：352-360

Coexisting H2O influenced the formation NO2 adspecies and unidentate nitrate, while SO2

slightly inhibited the formation of NO2/NO3− species, but promoted the formation of

acetate/formate species during NO reduction by C3H8.


2.4.6 Monolithic cordierite-based Fe/Al2O3 catalysts for NO reduction with C2H6

SEM of Fe/Al2O3/cordierite

（a）CM after acid solutiontreatment

（b）Al2O3/CM

（c）5.5Fe/Al2O3/CM （d）8Fe/Al2O3/CM

200 300 400 500 600

0

20

40

60

80

100

2Fe/Al2O

3/CM

3.5Fe/Al2O

3/CM

5.5Fe/Al2O

3/CM

8Fe/Al2O

3/CM

5Fe/CM Al

2O

3/CM

Fe2O

3

NO

x C

onve

rsio

n (%

)

Temperature (℃)

(a)

200 300 400 500 600

0

10

20

30

40

50

60

70

80

2Fe/Al2O

3/CM

3.5Fe/Al2O

3/CM

5.5Fe/Al2O

3/CM

8Fe/Al2O

3/CM

5Fe/CM Al

2O

3/CM

Fe2O

3

C2 H

6 C

onve

rsio

n (%

)

Temperature (℃)

(b)

NOx conversion to N2 (a), C2H6 conversion (b) over Fe/Al2O3/cordierite (500 ppm NO, 1000 ppm C2H6, and GHSV=18000 h-1)

4000 3500 3000 2500 2000 1500 1000

1303

157

0

124

013

22

142

0

222

0

190

318

42

1602

1628

RT in NO

400°C

350°C

300°C

250°C

200°C

150°C

100°C

50°C

Abso

rban

ce (

a.u.)

Wavenumber (cm-1

)

RT in NO and C2H

6

3730

377

0

0.1

Infrared spectra in the absence of O2 after the 5.5Fe/Al2O3/CM catalyst was exposed to 2% NO for 30 min followed by introduction of 2% C2H6 at room temperature.

10 20 30 40 50 60 70 80

●

●

●

●

○

3.5Fe/Al2O3/CM

5.5Fe/Al2O3/CM

○ 2Al2O3·2MgO·5SiO2 ●Fe2O3

8Fe/Al2O3/CM

2Fe/Al2O3/CM

Al2O3/CM

Cordierite○

○○○○○

○○○○○

○

● ●

Inte

nsi

ty (

CP

S)

2θ (°)

XRD pattern

Hao Zhou, Yaxin Su*, Wenyu Liao, et al. Applied Catalysis A: General, 2015, 505: 402- 409

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2.5 Quantum chemistry calculation of NO +Fe2

B3LYP/6-311+G(d, p) basis set

Gaussian 09


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Erel/（kCal ∙ mol-1） E'/( kCal ∙ mol-1)

octet decuplet octet decuplet

Fe2+NO 0 4.21 - -

C1(C1') -48.25 -25.20 - -

TS1(TS1') -26.88 -16.97 21.37 8.23

C2(C2') -50.86 -32.63 - -

TS2(TS2') -40.76 -28.26 10.10 4.37

C3(C3') -64.84 -61.88 - -

TS3(TS3') -54.19 -39.72 10.65 22.16

C4(C4') -54.58 -39.86 - -

TS4(TS4') -5.05 -9.25 49.53 30.61

Fe2O+N -71.47 -102.24 - -

benchmark

Reaction activation energy results from the cleavage of N-O bond.

Energies of various species in reaction of Fe2+NO→Fe2O+N on two state PES

2.6 Microwave-Induced Sewage Sludge Pyrolysis

2.6.1 Microwave heating introduction

Single-mode microwave heating device

Microwave heating principle

Main Advantages of microwave heating

Precisely controllable and can be turned on and off instantly

More compact, requiring a smaller equipment footprint

Non-contact heating technology

Microwave energy provides uniform energy distribution

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0

50

100

150

200

250

300

350

400

450

0

100

200

300

400

500

600

700

800

900

0 5 10 15 20 25

Tempera ture

Gas product

Tem

per

autr

e/⁰C

Gas

pro

duct

flo

w rat

e/m

l min

-1

t/min

(b)

温度

气相产物

温度

气相产率

/(m

l/m

in)

Gas production evolution during microwave pyrolysis

Tem

pera

ture

Gas

pro

duct

ion

0

5

10

15

20

25

30

35

40

45

50

55

60

65

CO2CH4COH2

ZnCl2: DS=1:2

(wt/wt)水蒸气流量1.59g/min

Gas

con

cent

rati

on /

vol

.%

400-700℃ 700-850℃ >850℃

CaO: DS=1:2 (wt/wt)水蒸气流量 1.59g/min

H2 CO CH4 CO2

体积分数/vol.%

800~950℃

700~800℃

400~700℃

Pyrolysis gas distribution under combined effect of catalyst and steam

Vol

um

e fr

acti

on

Steam flow Steam flow

2.6.2 Sewage sludge pyrolysis for hydrogen production

0

5

10

15

20

25

30

35

40

45

50

55

60

65

Gas

con

centr

atio

n /

vol.

%

DS CaO: DS=1:2(wt/wt)

ZnCl2: DS=1:2(wt/wt)

水蒸气流量 1.59g/min

CaO: DS=1:2(wt/wt),水蒸气

流量1.59g/min ZnCl2: DS=1:2(wt/wt),水蒸气

流量1.59g/min

H2 CO CH4 CO2

体积分数/vol.%

CaO:DS = 1:2

ZnCl2:DS = 1:2

CaO:DS = 1:2, 水蒸气流量1.59 g/min

ZnCl2:DS = 1:2, 水蒸气流量1.59 g/min

水蒸气流量1.59 g/min

Comparison of gaseous distributions under different microwave pyrolysisconditions (850 ºC)

Vol

um

e fr

acti

on

Steam flow

Steam flow

Steam flow


2.6.3 Methane decomposition over sludge residue for hydrogen production

0

100

200

300

400

500

600

700

800

900

1000

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 20 40 60 80 100 120

320 W, 0.3 L g-1 h-1

320 W, 0.15 L g-1 h-1

320 W,0.3 L g-1 h-1

320 W, 0.15 L g-1 h-1

A

B

a

b

100

80

60

40

20

0

Time (min)

Tem

per

atu

re (

ºC)

CH

4co

nv

ersi

on

(%

)

Temperature and methane conversion over pyrolysis residue under microwave heating. A and a: 320 W, 0.3 L g-1 h-1; B and b: 320 W, 0.15 L g-1 h-1.

0

1000

2000

3000

4000

5000

6000

0 10 20 30 40 50 60 70 80 90

2θ (º)

Co

un

ts

(a)

(b)

Quartz – SiO2

Anorthite – CaAl2(SiO2)4

Kaolinite – Al2SiO5

XRD ananlysis of the molten beads

Molten beads (left) and nano-tubes formed over pyrolysis residue by microwave induced methane decomposition.

Wenyi Deng, Yaxin Su, Shugang Liu, et al. International Journal of Hydrogen Energy. 2014, 39: 9169-9179.

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3. Professors outside China visit my lab

3.1 Prof Wei-Yin Chen, the University of Mississippi, USA, 2003, 2005, 2009


3.2 Prof Miguel Castro, Universidad Nacional Autónoma de México (UNAM), 2015.10

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3.3 Prof Saffa Riffat，the University of Nottingham, UK, 2004, 2015;

4. My group

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4. My group

Thank you and welcome to visit Shanghai!

Recent research on combustion and NOx emission control at Donghua University

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