Oxy-moderate or intense low-oxygen dilution (MILD) combustion, which is a novel combination of oxy-fuel technology and MILD regime, is numerically studied in the present work. The effects of external preheating and CO2 dilution level on the combustion field, emission, and CO formation mechanisms are investigated in a recuperative laboratory-scale furnace with a recirculating cross-flow. Reynolds-averaged Navier–Stokes (RANS) equations with eddy dissipation concept (EDC) model are employed to perform a 3-D simulation of the combustion field and the turbulence–chemistry interactions. In addition, a well-stirred reactor (WSR) analysis is conducted to further examine the chemical kinetics of this combination when varying the target parameters. The simulations used the skeletal USC-Mech II, which has been shown to perform well in the oxy-fuel combustion modeling. Results show that with more preheating, the uniformity of temperature distribution is noticeably enhanced at the cost of higher CO emission. Also as inlet temperature increases, the concentration of minor species rises and CO formation through the main path (CH4→CH3→CH2O→HCO→CO→CO2) is strengthened, while heavier hydrocarbons path (C2H2→CO) is suppressed. Meanwhile, greater CO2 addition notably closes the gap between maximum and exhaust temperatures. In a highly CO2-diluted mixture, chain-branching reactions releasing CH2O are strengthened, while chain-terminating reactions are weakened. CH2O production through CH3O is accelerated compared with the straight conversion of methyl to formaldehyde. When diluting the oxidant, methylene CH2(s) plays a more influential role in CO formation than when pure oxygen is used, contributing to higher CO emission.

References

References
1.
Chu
,
S.
,
2009
, “
Carbon Capture and Storage
,”
Science
,
325
(
5948
), p.
1599
.
2.
Wall
,
T.
,
2007
, “
Combustion Processes for Carbon Capture
,”
Proc. Combust. Inst.
,
31
(
1
), pp.
31
47
.
3.
Buhre
,
B. J. P.
,
Elliott
,
L. K.
, and
Sheng
,
C. D.
,
2005
, “
Oxy-Fuel Combustion Technology for Coal-Fired Power Generation
,”
Prog. Energy Combust. Sci.
,
31
(
4
), pp.
283
307
.
4.
Pryor
,
O.
,
Barak
,
S.
,
Lopez
,
J.
,
Ninnemann
,
E.
, and
Koroglu
,
B.
,
2017
, “
High Pressure Shock Tube Ignition Delay Time Measurements During Oxy-Methane Combustion With High Levels of CO2 Dilution
,”
ASME J. Energy Resour. Technol.
,
139
(
4
), p.
042208
.
5.
Manikantachari
,
K. R. V.
,
Vesely
,
L.
,
Martin
,
S.
,
Diaz
,
J.
, and
Vasu
,
S.
,
2018
, “
Reduced Chemical Kinetic Mechanisms for Oxy/Methane Supercritical CO2 Combustor Simulations
,”
ASME J. Energy Resour. Technol.
,
140
(
9
), p.
092202
.
6.
Chen
,
L.
, and
Yong
,
S. Z.
,
2012
, “
Oxy-Fuel Combustion of Pulverized Coal: Characterization, Fundamentals, Stabilization and CFD Modeling
,”
Prog. Energy Combust. Sci.
,
38
(
2
), pp.
156
214
.
7.
Normann
,
F.
,
Andersson
,
K.
,
Leckner
,
B.
, and
Johnsson
,
F.
,
2009
, “
Emission Control of Nitrogen Oxides in the Oxy-Fuel Process
,”
Prog. Energy Combust. Sci.
,
35
(
5
), pp.
385
397
.
8.
Zarzycki
,
R.
, and
Panowski
,
M.
,
2017
, “
Analysis of the Flue Gas Preparation Process for the Purposes of Carbon Dioxide Separation Using the Adsorption Methods
,”
ASME J. Energy Resour. Technol.
,
140
(
3
), p.
032008
.
9.
Breault
,
R.
, and
Shadle
,
L.
,
2018
, “
Design, Development, and Operation of an Integrated Fluidized Carbon Capture Unit Using Polyethylenimine Sorbents
,”
ASME J. Energy Resour. Technol.
,
140
(
6
), p.
062202
.
10.
Li
,
P.
,
Mi
,
J.
,
Dally
,
B. B.
,
Wang
,
F.
, and
Wang
,
L.
,
2011
, “
Progress and Recent Trend in MILD Combustion
,”
Sci. China
,
54
(
2
), pp.
255
269
.
11.
Wunning
,
J. A.
, and
Wunning
,
J. G.
,
1997
, “
Flameless Oxidation to Reduce Thermal NO-Formation
,”
Prog. Energy Comb. Sci.
,
23
(
1
), pp.
81
94
.
12.
Cavaliere
,
A.
, and
Joannon
,
M. D.
,
2004
, “
Mild Combustion
,”
Progress Energy Combust. Sci.
,
30
(
4
), pp.
329
366
.
13.
Feser
,
J.
, and
Gupta
,
A. K.
,
2018
, “
Effect of CO2/N2 Dilution on Premixed Methane–Air Flame Stability Under Strained Conditions
,”
ASME J. Energy Resour. Technol.
,
140
(
7
), p.
072207
.
14.
Krishnamurthy
,
N.
,
Paul
,
P. J.
, and
Blasiak
,
W.
,
2009
, “
Studies on Low-Intensity Oxy-Fuel Burner
,”
Proc. Combust. Inst.
,
32
(
2
), pp.
3139
3146
.
15.
Stadler
,
H.
,
Christ
,
D.
,
Habermehl
,
M.
,
Heil
,
P.
,
Kellermann
,
A.
,
Ohliger
,
A.
,
Toporov
,
D.
, and
Kneer
,
R.
,
2011
, “
Experimental Investigation of NOx Emissions in Oxycoal Combustion
,”
Fuel
,
90
(
4
), pp.
1604
1611
.
16.
Heil
,
P.
,
Toporov
,
D.
,
Forster
,
D.
, and
Knee
,
R.
,
2011
, “
Experimental Investigation on the Effect of O2 and CO2 on Burning Rates During Oxy-Fuel Combustion of Methane
,”
Proc. Combust. Inst.
,
33
(
2
), pp.
3407
3413
.
17.
Liu
,
R.
, and
An
,
E.
,
2017
, “
Turbulent Flame Characteristics of Oxy-Coal MILD Combustion
,”
ASME J. Energy Resour. Technol.
,
139
(
6
), p.
062206
.
18.
Mei
,
Z.
,
Mi
,
J.
,
Wang
,
F.
, and
Zheng
,
Z.
,
2012
, “
Dimensions of CH4-Jet Flame in Hot O2/CO2 Co-Flow
,”
Energy Fuels
,
26
(
6
), pp.
3257
3266
.
19.
Li
,
P.
,
Dally
,
B. B.
,
Mi
,
J.
, and
Wang
,
F.
,
2013
, “
MILD Oxy-Combustion of Gaseous Fuels in a Laboratory-Scale Furnace
,”
Combustion Flame
,
160
(
5
), pp.
933
946
.
20.
Mardani
,
A.
, and
Fazlollahi
,
A.
,
2016
, “
Numerical Study of Oxy-Fuel MILD (Moderate or Intense Low-Oxygen Dilution Combustion) Combustion for CH4/H2
,”
Energy
,
99
(
15
), pp.
136
151
.
21.
Sabia
,
P.
,
Sorrentino
,
G.
,
Chinnici
,
A.
,
Cavaliere
,
A.
, and
Ragucci
,
R.
,
2015
, “
Dynamic Behaviors in Methane MILD and Oxy-Fuel Combustion. Chemical Effect of CO2
,”
Energy Fuels
,
29
(
3
), pp.
1978
1986
.
22.
Almansour
,
B.
,
Thompson
,
L.
,
Lopez
,
J.
,
Barari
,
G.
, and
Vasu
,
S. S.
,
2015
, “
Laser Ignition and Flame Speed Measurements in Oxy-Methane Mixtures Diluted With CO2
,”
ASME J. Energy Resour. Technol.
,
138
(
3
), p.
032201
.
23.
Szego
,
G. G.
,
Dally
,
B. B.
, and
Nathan
,
G. J.
,
2009
, “
Operational Characteristics of a Parallel Jet MILD Combustion Burner System
,”
Combust. Flame
,
156
(
2
), pp.
429
438
.
24.
Szego
,
G. G.
,
2010
, “
Experimental and Numerical Investigation of a Parallel Jet Mild Combustion Burner System in a Laboratory Scale Furnace
,” Ph.D. Thesis,
The University of Adelaide
,
Adelaide, South Australia, Australia
.
25.
Pope
,
S. B.
,
1997
, “
Computationally Efficient Implementation of Combustion Chemistry Using In Situ Adaptive Tabulation
,”
Combust. Theory Modell.
,
1
(
1
), pp.
41
63
.
26.
Orszag
,
S.
,
Yakhot
,
A.
,
Flannery
,
V.
,
Boysan
,
W. S.
,
Choudhury
,
F.
,
Maruzewski
,
J.
, and
Patel
,
B.
,
1993
, “
Renormalization Group Modeling and Turbulence Simulations
,”
International Conference, Near-Wall Turbulent Flows
,
Tempe, AZ
,
March
.
27.
De
,
A.
,
Oldenhof
,
E.
,
Sathiah
,
P.
, and
Roekaerts
,
D.
,
2011
, “
Numerical Simulation of Delft-Jet-in-Hot-Coflow (DJHC) Flames Using the Eddy Dissipation Concept Model for Turbulence–Chemistry Interaction
,”
Flow Turb. Combust.
,
87
(
4
), pp.
537
567
.
28.
Gran
,
I. R.
, and
Magnussen
,
B. F.
,
1996
, “
The Eddy Dissipation Concept
,”
Combust. Sci. Technol.
,
119
(
1–6
), pp.
191
217
.
29.
Delphine
,
L.
, and
Paul
,
L.
,
2015
, “
Assessment of the EDC Combustion Model in MILD Conditions With In-Furnace Experimental Data
,”
Appl. Therm. Eng.
,
75
(
22
), pp.
93
102
.
30.
Mardani
,
A.
,
Tabejamaat
,
S.
, and
Hassanpour
,
S.
,
2013
, “
Numerical Study of CO and CO2 Formation in CH4/H2 Blended Flame Under MILD Condition
,”
Combust. Flame
,
160
(
9
), pp.
1636
1649
.
31.
Li
,
P.
,
Wang
,
F.
,
Mi
,
J.
,
Dally
,
B.B.
, and
Mei
,
Z.
,
2014
, “
MILD Combustion Under Different Premixing Patterns and Characteristics of the Reaction Regime
,”
Energy Fuels
,
28
(
3
), pp.
2211
2226
.
32.
Hu
,
F.
, and
Li
,
P.
,
2018
, “
Evaluation, Development, and Validation of a New Reduced Mechanism for Methane Oxy-Fuel Combustion
,”
Int. J. Green. Gas. Con.
,
78
, pp.
327
340
.
33.
Wang
,
H.
,
You
,
X.
,
Joshi
,
A.V.
,
Davis
,
S. G.
,
Laskin
,
A.
,
Egolfopoulos
,
F.
, and
Law
,
C.
,
2007
,
USC Mech Version II. High-Temperature Combustion Reaction Model of H2/CO/C1-C4 Compounds
. http://ignis.usc.edu/Mechanisms/USC-Mech%20II/USC_Mech%20II.htm. Accessed May 2007.
34.
Yu
,
G.
,
Metghalchi
,
H.
,
Askari
,
O.
, and
Wang
,
Z.
,
2018
, “
Combustion Simulation of Propane/Oxygen (With Nitrogen/Argon) Mixtures Using Rate-Controlled Constrained-Equilibrium
,”
ASME J. Energy Resour. Technol.
,
141
(
2
), p.
022204
.
35.
Porter
,
R.
,
Liu
,
F.
,
Pourkashanian
,
M.
,
Williams
,
A.
, and
Smith
,
D. J.
,
2010
, “
Evaluation of Solution Methods for Radiative Heat Transfer in Gaseous Oxy-Fuel Combustion
,”
Quant. Spectrosc. Rad.
,
111
(
14
), pp.
2084
2094
.
36.
Gharebaghi
,
M.
,
Irons
,
R. M. A.
,
Ma
,
L.
,
Pourkashaniana
,
M.
, and
Pranzitelli
,
A.
,
2011
, “
Large Eddy Simulation of Oxy-Coal Combustion in an Industrial Combustion Test Facility
,”
Int. J. Green. Gas. Con.
,
5
(
1
), pp.
100
110
.
37.
Cumber
,
P. S.
,
Fairweather
,
M.
, and
Ledin
,
H. S.
,
1998
, “
Application of Wide Band Radiation Models to Non-Homogeneous Combustion Systems
,”
Int. J. Heat. Mass. Transfer.
,
41
(
11
), pp.
1573
1584
.
38.
Bilger
,
R. W.
,
Stårner
,
S. H.
, and
Kee
,
R. J.
,
1990
, “
On Reduced Mechanisms for Methane-Air Combustion in Non-Premixed Flames
,”
Combust. Flame
,
80
(
2
), pp.
135
149
.
39.
Wang
,
F.
,
Li
,
P.
,
Mei
,
Z.
,
Zhang
,
J.
, and
Mi
,
J.
,
2014
, “
Combustion of CH4/O2/N2 in a Well Stirred Reactor
,”
Energy
,
72
(
1
), pp.
242
253
.
40.
Levy
,
Y.
,
Sherbaum
,
V.
, and
Erenburg
,
V.
,
2007
, “
The Role of the Recirculating Gases at the Mild Combustion Regime Formation
,”
ASME Turbo Expo 2007: Power for Land, Sea, and Air
, pp.
271
278
, Paper No. GT2007-27369.
41.
Glarborg
,
P.
,
Kee
,
R. J.
,
Grcar
,
J. F.
, and
Miller
,
J. A.
,
1986
, “
PSR: A Fortran Program for Modeling Well-Stirred Reactors
,”
Sandia National Laboratories
, Report No. SAND86-8209.
You do not currently have access to this content.