ben kumfer scott skeen richard axelbaum laboratory for advanced combustion & energy research
DESCRIPTION
Cofiring of Coal and Biomass Under Oxycombustion Conditions: NOx Formation and PM Characterization. Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research Dept. of Energy, Environmental & Chemical Engineering, Washington University in St. Louis, MO. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/1.jpg)
Cofiring of Coal and Biomass Under Oxycombustion Conditions:
NOx Formation and PM Characterization
Ben KumferScott Skeen
Richard Axelbaum
Laboratory for Advanced Combustion & Energy ResearchDept. of Energy, Environmental & Chemical Engineering,
Washington University in St. Louis, MO
![Page 2: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/2.jpg)
Oxy-Fuel with Carbon Capture
Cofiring Biomass:
•Potentially Carbon negative means of power generation
•Utilizes renewable fuels
biomass
CO2
[CO2] > 95% (dry)
air separation
unit
purification
compression
coal
FGR
geo -sequestration
O2
N2air
• High CO2 concentration in flue gas
• Parasitic load for air-separation
• Large reduction in NOx can result through RFG
• Potential for improved boiler efficiency
![Page 3: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/3.jpg)
Conventional vs. Oxy-Combustion
Conventional Coal/Air Combustion
air
coal+airPrimary
Oxy-Coal Combustion
air
Secondary
Secondary
O2+RFG
fuel+RFG+O2
Secondary
Secondary O2+RFG
Primary
Questions:
Is there an optimum set of PO and SO compositions for NOx?
What is the influence of oxy-combustion on ash properties?
What are the consequences of cofiring biomass under air-fired and oxy-combustion conditions?
![Page 4: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/4.jpg)
30 kW, Horizontally-Fired Test System
4
Fuels:•Coal: Powder River Basin, HV = 30 MJ/kg•Waste Sawdust, HV = 22 MJ/kg
Instruments (Thermo Inc):• 100:1 Dilution probe system for gas sampling• CEM w/ chemiluminescence NOx analyzer• Dekati ELPI particle analyzer
ELPI
diffusion dryer
![Page 5: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/5.jpg)
Fuel Properties
5
coal
10 µm
10 µm
sawdust
![Page 6: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/6.jpg)
Air-Fired Results: Variable Primary Stoichiometry
stO
POO
stair
POairPO m
m
m
m
,
,
,
,
2
2
coal+PO
SO
SO
Constant PO Flow Rate Constant Thermal Input
axial tangential (full swirl)
SO flow:
![Page 7: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/7.jpg)
Effects of Variable Secondary Swirl
coal+PO
SO
SO
Air-fired vs. Oxy-combustionRun conditions: synthetic oxidizer: 30%(v) O2, 70% CO2, in PO and SO 3%(v) O2 in exhaust 30 kW
= 5.2 m3/hr
SO_tangential / SO_total
![Page 8: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/8.jpg)
Variable [O2] in PO and SO
30 kW 3%(v) O2 in exhaust
constant total O2:CO2
coal+PO
SO
SO
axial SO
tangential SO
tangential SO
![Page 9: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/9.jpg)
Sawdust Cofiring
sawdust sieved 20 mesh
sawdust sieved 50 mesh
![Page 10: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/10.jpg)
Summary: NOx
Nitric oxide emissions are strongly dependent on flame attachment
Flow rate reductions required under oxy-fuel conditions can dramatically influence flame hydrodynamics and thus NOx
An optimum PO & SO composition was observed
Fuel particle size is an important consideration for NOx when cofiring with biomass.
![Page 11: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/11.jpg)
PM Size Distribution & Morphology
5.0 µm
100% coaldpaero = 5.18 µm
1.0 µm
cofired, (50% wt. sawdust)dpaero = 330 nm
5.0 µm
cofired, (50% wt. sawdust)dpaero = 5.18 µm
![Page 12: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/12.jpg)
Elemental Analysis: Oxycoal
![Page 13: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/13.jpg)
Elemental Analysis: Cofired
![Page 14: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/14.jpg)
Effect of Temperature
• Oxidizer is a mixture of O2 and CO2
• Formation of submicron PM increases with O2 concentration.
• This effect is due to increased combustion temperature.
![Page 15: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/15.jpg)
Acknowledgments
Consortium for Clean Coal Utilization at Washington University http://www.c3u.wustl.edu/
DOE UCR Program
Ameren UE
![Page 16: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/16.jpg)
Extras
16
Base/Acid ratio, an indication of slagging propensity, is higher in submicron PM.
B/A = (Fe2O3+CaO+MgO+Na2O+K2O)/(Al2O3+SiO2+TiO2)
![Page 17: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/17.jpg)
Effect of Temperature
![Page 18: Ben Kumfer Scott Skeen Richard Axelbaum Laboratory for Advanced Combustion & Energy Research](https://reader036.vdocument.in/reader036/viewer/2022062520/56815c34550346895dca1979/html5/thumbnails/18.jpg)
Critical PO Stoichiometry
• No SO Swirl
• 40 vol.% O2 in PO
• 28 vol.% O2 in SO
• Vary thermal input (i.e. vary λPO)
coal+PO
SO
SO