Development of 0.1MW- class Oxy- PC Swirl Burner with Primary O 2 - - PowerPoint PPT Presentation

Development of 0.1MW- class Oxy- PC Swirl Burner with Primary O

2 Direct- injection

Korea Institute of Energy Research Dae Keun Lee, Dong- Soon Noh, Kyong- Bin Choi, Dong Myung Seo, Chang- Bog Ko, Eun Kyung Lee

1st International Oxyfuel Combustion Conference Cottbus, Germany 8th September 2009

1st International Oxyfuel Combustion Conference 2/25

Contents

► Background ► Objective ► Design Concepts of Oxy- PC Burner ► Experimental Results ► Summary

1st International Oxyfuel Combustion Conference 3/25

Ai Air- PC

Background

O x O xy- PC

Retrofit or new build

O

2 : CO 2 ~ 30 : 70

► F

G R for T control

• Similar T field with Air- PC

les s en the load for boiler des ign.

► Amount of recycled gas

• O

2 : FGR (CO 2) ~ 30 : 70

• Les s volume of CO

2 than

that of N2 ฀ Larger Cp of CO

2 than N2

► Then, similar T field?

1st International Oxyfuel Combustion Conference 4/25

Objective

► Matching conditions of temperature fields of

Air- & Oxy- firing

• Test of Air- & Oxy- firing using single burner

► Coaxial nozzle type s wirl burner ► Mixing nozzle type s wirl burner

• Oxy- PC burner design parameters
• Test of newly designed Oxy- PC burner

1st International Oxyfuel Combustion Conference 5/25

Test Facility

► Furnace

• Cylindrical & horizontal
• 11 sampling & measuring ports
• Tertiary oxidant injection ports through side wall

3.2m 450mm

1st International Oxyfuel Combustion Conference 6/25

Coal

► Test coal

• Australian bituminous coal
• Coal analyses

1st International Oxyfuel Combustion Conference 7/25

Tested Burners

► Coaxial nozzle type swirl burner ► Mixing nozzle type swirl burner ► Multi- nozzle type swirl burner

1st International Oxyfuel Combustion Conference 8/25

Burner Design 1

Burner Nozzle type Air- firing Oxy- firing Coaxial nozzle burner

Secon

• ndary

swirl n nozzl zzle Coal n l nozzl zle Coal + l + Prima imary y air Secon

• ndary

air Coal + l + Prima imary y O2

2 /CO

CO2 Secon

• ndary

O2

2 /CO

CO2

► Coaxial nozzle burner

• Conventional design for Air- PC firing
• 1st & 2nd O

2 diluted by CO 2

• Comparison of Air- & Oxy- firings using the same burner

1st International Oxyfuel Combustion Conference 9/25

Result: Coaxial Nozzle Burner

► Temperature fields

• @ 0.1MWth, swirl no.=0.7
• Similar downsteam but different upstream
• Air- PC,
• Oxy- PC, O

2/CO 2=29/71

• Oxy- PC, O

2/CO 2=31/69

1st International Oxyfuel Combustion Conference 10/25

Result: Coaxial Nozzle Burner

► Centerline temperature

• Too cold @ O

2/CO 2=29/71

• Upstream T can be increased by O

2 enrichment.

• But still lower than that of Air- firing by 80K.
• How to locally enrich O

2 in near- field?

1st International Oxyfuel Combustion Conference 11/25

Burner Design 2

Burner Nozzle type Air- firing Oxy- firing Mixing nozzle burner

Secon

• ndary

swirl n nozzl zzle Oxy n y nozzl zzle Coal n l nozzl zle Coal + l + Prima imary y CO2 Secon

• ndary

O2

2 /CO

CO2 Prima imary y O2 Coal + l + Prima imary y air Secon

• ndary

air Not

• t u

use sed

► Mixing nozzle burner

• Design for primary O

2 direct- injection for Oxy- firing

• Attempt to increase the near- field temperature

by local enrichment of O

2

• Comparison of Air- & Oxy- firings using the same burner

1st International Oxyfuel Combustion Conference 12/25

Result: Mixing Nozzle Burner

► Centerline temperatures

• Much lower T than Air- firing over the whole region
• Maybe due to mixing retardation
• Then the hydrodynamic effects?

Centerline temperature [oC]

1st International Oxyfuel Combustion Conference 13/25

Result: Mixing Nozzle Burner

► Hydrodynamic effects

• Total gas flow rates equally sustained by power increase
• Similar T patterns can be obtained if hydrodynamically similar
• Then how to make similar hydrodynamic field?

Centerline temperature [oC]

1st International Oxyfuel Combustion Conference 14/25

Simple Estimates

► Thermal similarity

► Hydrodynamic similarity

• The same heating
• The same momentum flow rate

Difficult to make field- s imilarities by Oxy- firing of Air- PC burner

O2/N2 or O2/CO2 O2/N2 or O2/CO2

1st International Oxyfuel Combustion Conference 15/25

Swirling Momentum

► Another consideration for hydrodynamic similarity

• Swirling momentum controls

near- field flame shape.

► Two parameters to be matched with those of Air-

firing

• Axial momentum flow rates
• Swirling momentum flow rates

► How to make these @ the same power cond.

1st International Oxyfuel Combustion Conference 16/25

Strategy

► Problem

• Smaller volume flow rate of CO

2 than that of N2

• Momentum flow rates of Oxy- firing less than those of Air-

firing

• How to make the equal momentum flows

► Our strategy

• To make a smaller Oxy- burner than Air- burner

to match the axial & swirling momentum flow rates @ the same heating/power condition

• Scale- down of coal & swirl nozzles

1st International Oxyfuel Combustion Conference 17/25

Burner Design 3

Burner Nozzle type Air- firing Oxy- firing Multi nozzle burner

6 Oxy no xy nozzl zzle in coal n nozzl zzle Secon

• ndary

swirl n nozzl zzle Secon

• ndary

O2

2 /CO

CO2 Coal + l + Prima imary y CO2 Prima imary y O2

► Multi- nozzle burner

• Axial & swirling momentum matched with

those of air- fired coaxial nozzle burner

• Primary O

2 direct- injection to enhance flame stability

Coal + l + Prima imary y air Secon

• ndary

air

Coaxial burner

1st International Oxyfuel Combustion Conference 18/25

Result: Multi Nozzle Burner

► Temperature fields @ 0.1MWth

• For Oxy- firing, O

2/CO 2=29/71

• Slender flame broadened by swirl number
• Near- field T increases as swirl number.
• Coaxial nozzle burner, Air- firing, Swirl=0.7
• Multi- nozzle burner, O

xy- firing, Swirl=0.39

• Multi- nozzle burner, O

xy- firing, Swirl=0.70

• Multi- nozzle burner, O

xy- firing, Swirl=1.05

1st International Oxyfuel Combustion Conference 19/25

Result: Multi Nozzle Burner

► Centerline temperatures

• Largely increased upstream T than other two burners
• Difference of downstream T <30K

1st International Oxyfuel Combustion Conference 20/25

Result: Multi Nozzle Burner

• Air- PC, 0.1MWth, Swirl=0.7
• Oxy- PC, 0.1MWth, O

2/CO 2=29/71, Swirl=0.7, 1st O 2/2nd O 2=30/70

• Oxy- PC, 0.1MWth, O

2/CO 2=29/71, Swirl=0.7, 1st O 2/2nd O 2=25/75

► Effects of 1st vs. 2nd O

2 flow rates

• Very sensitive on 1st/2nd O

2

1st International Oxyfuel Combustion Conference 21/25

Result: Multi Nozzle Burner

► Centerline temperatures

• Very sensitive near- field T on 1st/2nd O

2

• Optimal condition:

25%<1st O

2<30% @ equal swirl no. to Air- firing coaxial burner

1st International Oxyfuel Combustion Conference 22/25

Exhaust CO

2

► CO

2 exhaust concentration for multi nozzle burner

• Larger than 95%
• Max. of 97.9%

1st International Oxyfuel Combustion Conference 23/25

NO

x Reduction

48mg/MJ

► NO

x reduction by tertiary oxidant injection

for multi nozzle burner

• Staged supply of oxidant

through side wall of the furnace

• Reduced emission as injection position

& amount

No tertiary injection

CO<30ppm

1st International Oxyfuel Combustion Conference 24/25

Summary

► Attempt to make a s imilar T field of O

xy- firing to that of Air- firing

► Coaxial & mixing nozzle burners

• Difficult to make similar fields by Oxy- firing
• Hydrodynamic effects on T field were more important than expected.

► Multi- nozzle burner

• Scale- down to match the axial & swirling momentums

to that of Air- firing of coaxial burner

• Most similar T field

@ O

2/CO 2=29/71, the equal swirl number and 25%<1st O 2<30%

► Exhaus t CO

2>95% for multi- nozzle burner

NOx emis s ion<60mg/MJ by tertiary oxidant injection

Thank you for your attention!

Dae Keun Lee, Ph.D. Energy Eff. & Materials Convergence Research Division Korea Institute of Energy Research dklee@kier.re.kr