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

1st International Oxyfuel Combustion Conference Contents ► Background ► Objective ► Design Concepts of Oxy- PC Burner ► Experimental Results ► Summary 2 /25

1st International Oxyfuel Combustion Conference Background ► F G R for T control Air- PC Ai  Similar T field with Air- PC les s en the load for boiler des ign. ► Amount of recycled gas Retrofit or  O 2 : FGR (CO 2 ) ~ 30 : 70 new build  Les s volume of CO 2 than that of N 2 O O xy- PC x ฀ Larger C p of CO 2 than N 2 ► Then, similar T field? O 2 : CO 2 ~ 30 : 70 3 /25

1st International Oxyfuel Combustion Conference 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 4 /25

1st International Oxyfuel Combustion Conference Test Facility ► Furnace  Cylindrical & horizontal  11 sampling & measuring ports  Tertiary oxidant injection ports through side wall 450mm 3.2m 5 /25

1st International Oxyfuel Combustion Conference Coal ► Test coal  Australian bituminous coal  Coal analyses 6 /25

1st International Oxyfuel Combustion Conference Tested Burners ► Coaxial nozzle type swirl burner ► Mixing nozzle type swirl burner ► Multi- nozzle type swirl burner 7 /25

1st International Oxyfuel Combustion Conference Burner Design 1 Burner Nozzle type Air- firing Oxy- firing Coal + l + Coal + l + Prima imary y air Prima imary y O 2 2 /CO CO 2 Coal n l nozzl zle Coaxial nozzle Secon ondary burner Secon ondary Secon ondary swirl n nozzl zzle air O 2 2 /CO CO 2 ► Coaxial nozzle burner  Conventional design for Air- PC firing  1 st & 2 nd O 2 diluted by CO 2  Comparison of Air- & Oxy- firings using the same burner 8 /25

1st International Oxyfuel Combustion Conference Result: Coaxial Nozzle Burner ► Temperature fields  @ 0.1MW th , 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 9 /25

1st International Oxyfuel Combustion Conference 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? 10 /25

1st International Oxyfuel Combustion Conference Burner Design 2 Burner Nozzle type Air- firing Oxy- firing Coal + l + Coal + l + Prima imary y CO 2 Prima imary y air Coal n l nozzl zle Mixing Prima imary y O 2 Not ot u use sed Oxy n y nozzl zzle nozzle burner Secon ondary Secon ondary Secon ondary swirl n nozzl zzle O 2 2 /CO CO 2 air ► 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 11 /25

1st International Oxyfuel Combustion Conference 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 [ o C] 12 /25

1st International Oxyfuel Combustion Conference 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 [ o C] 13 /25

1st International Oxyfuel Combustion Conference Simple Estimates ► Hydrodynamic similarity ► Thermal similarity O 2 /N 2 or O 2 /N 2 or O 2 /CO 2 O 2 /CO 2  The same heating  The same momentum flow rate Difficult to make field- s imilarities by Oxy- firing of Air- PC burner 14 /25

1st International Oxyfuel Combustion Conference 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. 15 /25

1st International Oxyfuel Combustion Conference Strategy ► Problem  Smaller volume flow rate of CO 2 than that of N 2  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 16 /25

1st International Oxyfuel Combustion Conference Burner Design 3 Burner Nozzle type Air- firing Oxy- firing Coaxial burner Coal + l + Coal + l + Prima imary y CO 2 Multi Prima imary y air 6 Oxy no xy nozzl zzle Prima imary y O 2 in coal n nozzl zzle nozzle burner Secon ondary Secon ondary Secon ondary swirl n nozzl zzle air O 2 2 /CO CO 2 ► Multi- nozzle burner  Axial & swirling momentum matched with those of air- fired coaxial nozzle burner  Primary O 2 direct- injection to enhance flame stability 17 /25

1st International Oxyfuel Combustion Conference Result: Multi Nozzle Burner ► Temperature fields @ 0.1MW th  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 18 /25

1st International Oxyfuel Combustion Conference Result: Multi Nozzle Burner ► Centerline temperatures  Largely increased upstream T than other two burners  Difference of downstream T <30K 19 /25

1st International Oxyfuel Combustion Conference Result: Multi Nozzle Burner ► Effects of 1 st vs. 2 nd O 2 flow rates  Very sensitive on 1 st /2 nd O 2  Air- PC, 0.1MW th , Swirl=0.7 2 =29/71, Swirl=0.7, 1 st O 2 /2 nd O  Oxy- PC, 0.1MW th , O 2 /CO 2 =30/70 2 =29/71, Swirl=0.7, 1 st O 2 /2 nd O  Oxy- PC, 0.1MW th , O 2 /CO 2 =25/75 20 /25

1st International Oxyfuel Combustion Conference Result: Multi Nozzle Burner ► Centerline temperatures  Very sensitive near- field T on 1 st /2 nd O 2  Optimal condition: 25%<1 st O 2 <30% @ equal swirl no. to Air- firing coaxial burner 21 /25

1st International Oxyfuel Combustion Conference Exhaust CO 2 ► CO 2 exhaust concentration for multi nozzle burner  Larger than 95%  Max. of 97.9% 22 /25

1st International Oxyfuel Combustion Conference NO x Reduction ► 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 CO<30ppm injection 48mg/MJ 23 /25

1st International Oxyfuel Combustion Conference 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 2 =29/71, the equal swirl number and 25%<1 st O @ O 2 /CO 2 <30% ► Exhaus t CO 2 >95% for multi- nozzle burner NOx emis s ion<60mg/MJ by tertiary oxidant injection 24 /25

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