Design and operation of 350MW CFB boiler in China Man... · 350MW CFB Boiler General Arrangement...
Transcript of Design and operation of 350MW CFB boiler in China Man... · 350MW CFB Boiler General Arrangement...
Design and operation of 350MW CFB
boiler in China
Zhang Man
Tsinghua University, China
April, 2016, 72nd IEA-FBC, Budapest, Hungary
600MW CFB Boiler Operation
Item Unit Value
Main steam flow (BMCR) t/h 1900
Main steam pressure MPa 25.4
Main steam Temperature ℃ 571
Reheat steam flow t/h 1568.2
Inlet/outlet pressure of
reheated steam
MPa.a 4.58/4.43
Inlet/outlet temp. of reheated
steam
℃ 317/569
Feeding water Temp ℃ 284
Item Unite Value
Mar % 7.58
Aar % 43.82
Vdaf % 14.74
Qnet,ar kJ/kg 15173
Car % 41.08
Har % 1.62
Oar % 2.06
Nar % 0.54
Sar % 3.3
Economic and emission Performance
item Unit value
Unburnt carbon in fly ash % <2
Unburnt carbon in bottom ash % 1.0-2.0
O2 at the upstream of air pre-heater % 3.5-4.0
Exhaust flue gas temperature ℃ 130-135
SO2 (dry,6%O2) mg/Nm3 192
NOx (dry,6%O2) mg/Nm3 112
Boiler efficiency % 92.48
Heat flux profile along the furnace height
50% lower than that of the PC boiler, the
highest mainly in the taped section
covered with anti erosion layer
The flow rate can be lower as 500-800
kg/m2·s, much lower than that of PC boiler
of >1800 kg/m2·s
Lower flow rate has the feature of nature
circulation for Benson straight tube, i.e.
flow rate increases with higher heat flux
The temperature deviations decreases
Smooth tube can be used
The advantages of CFB boiler with supercritical parameters
rifled tube smooth tube
350MW CFB boiler
Boiler company Order Operation
Dongfang Boiler 40 8
Shanghai Boiler 18 2
Harbin Boiler 14 0
350MW CFB Boiler General Arrangement
Boiler with single reheat system is arranged as M model.
Dongfang boiler technical characteristics
Single furnace and single air grid.
Platen superheater, platen reheater and partition wall are designed in the furnace.
Feeding coal chutes are located on the lower part of the front wall.
Both of in duct burner and in bed burner are used for boiler ignition.
Rolling ash coolers are used. Bottom ash discharge opening are located at the bottom of the rear wall.
Three steam-cooled cyclones.
Flue gas damper is used for controlling the reheat steam temperature.
Partition wall
350MW CFB Boiler General Arrangement
Boiler with single reheat system is arranged as M model.
Shanghai boiler technical characteristics
Single furnace and single air grid.
Platen superheaters, platen reheaters and wing wall are designed in the furnace.
Feeding coal chutes are located on the lower part of the front wall.
Both of in duct burner and in bed burner are used for boiler ignition.
Rolling ash coolers are used. Bottom ash discharge opening are located at the air grid.
Three steam-cooled cyclones.
Flue gas damper is used for controlling the reheat steam temperature.
350MW CFB Boiler General Arrangement
Boiler with single reheat system is arranged as M model.
Harbin boiler technical characteristics
Single furnace and single air grid.
Platen superheaters, platen reheaters and wing wall are designed in the furnace.
Feeding coal chutes are located on the lower part of the front wall.
Both of in duct burner and in bed burner are used for boiler ignition.
Rolling ash coolers are used. Bottom ash discharge opening are located at the bottom of the rear wall.
Three steam-cooled cyclones.
Flue gas damper is used for controlling the reheat steam temperature.
Wing wall
350MW CFB Boiler Water Wall Medium Flow
Dongfang boiler
Average mass flow of the water wall and Partition wall is about 640kg/m2s at BMCR.
Partition wall
Wa
ter w
all
Pa
rtition
wa
ll
Rifled tube Smooth tube
Rifled tube
Smooth tube
Steam dryness
Metal temperature inside of the tube
350MW CFB Boiler Water Wall Medium Flow
Shanghai boiler
BMCR Unit Data
Front wall kg/m2s 890
Rear wall kg/m2s 850
Left wall kg/m2s 900
Right wall kg/m2s 900
Wingwall downcomer
kg/m2s
2500
Wingwall riser kg/m2s 1100
Wing wall Harbin boiler W
ing
wa
ll
Win
g w
all
Wa
ter w
all
Win
g w
all
Wa
ter w
all
Rifled tube Smooth tube
Rifled tube
Smooth tube
Steam dryness
Metal temperature inside of the tube
Operation results of 350MW CFB boiler
Metal temperature of the water wall is homogeneous; Metal temperature deviation is less than 30℃;
Dongfang Boiler
Operation results of 350MW CFB boiler
Metal temperature of the water wall is homogeneous, temperature difference is less than 7℃; Metal temperature difference of wing wall downcomer is less than 12℃; Metal temperature difference of wing wall raiser is less than 20℃;
Shanghai Boiler
Operation results of 350MW CFB boiler
Boiler was designed and manufactured by Dongfang boiler
Guojin Power Plant Operation Data
Load MW 352 Fuel Gangue
Main steam temperature ℃ 567
Main steam pressure MPa 23.72
Reheat steam temperature ℃ 563
Bed temperature ℃ 900
Oxygen content % 4.1
NOx original emission mg/Nm3 (dry,6%O2) <100
SO2 emission mg/Nm3 (dry,6%O2) 13.5
Lower secondary level m 2.5
Upper secondary level m 5
Auxiliary power rate % 6.5
Operation results of 350MW CFB boiler
Boiler was designed and manufactured by Dongfang boiler
Load MW 349 Fuel Gangue
Main steam temperature ℃ 568
Main steam pressure MPa 23.68
Reheat steam temperature ℃ 568
Bed temperature ℃ 885
Oxygen content % 3.6
NOx original emission mg/Nm3 (dry,6%O2) <70
SO2 emission mg/Nm3 (dry,6%O2) <35
Lower secondary level m 2.5
Upper secondary level m 5
Auxiliary power rate % 5.95
Unburnt Carbon in fly ash % 2.58
Unburnt Carbon in bottom ash % 1.8
Hequ Power Plant Operation Data
Operation results of 350MW CFB boiler
Boiler was designed and manufactured by Dongfang boiler
Load MW 350 Fuel Anthracite
Main steam temperature ℃ 573
Main steam pressure MPa 24.8
Reheat steam temperature ℃ 559
Bed temperature ℃ 940
Oxygen content % 3.5
NOx original emission mg/Nm3 (dry,6%O2) 120
SO2 emission mg/Nm3 (dry,6%O2) <35
Lower secondary level m 2.5
Upper secondary level m 5
Auxiliary power rate % 6.4
Unburnt Carbon in fly ash % 7
Unburnt Carbon in bottom ash % 2.1
Hepo Power Plant Operation Data
Operation results of 350MW CFB boiler
Boiler was designed and manufactured by Dongfang boiler
Load MW 349 Fuel Bituminous
Main steam temperature ℃ 568
Main steam pressure MPa 23.68
Reheat steam temperature ℃ 568
Bed temperature ℃ 880
Oxygen content % 3.6
NOx original emission mg/Nm3 (dry,6%O2) <50
SO2 emission mg/Nm3 (dry,6%O2) <35
Lower secondary level m 2.5
Upper secondary level m
Unburnt Carbon in fly ash % 5
Unburnt Carbon in bottom ash % 2
Huamei Power Plant Operation Data
Operation results of 350MW CFB boiler
Boiler was designed and manufactured by Shanghai boiler
Load MW 349 Fuel Gangue
Main steam temperature ℃ 568
Main steam pressure MPa 23.68
Reheat steam temperature ℃ 568
Bed temperature ℃ 935
Oxygen content % 4
NOx original emission mg/Nm3 (dry,6%O2) 140
SO2 emission mg/Nm3 (dry,6%O2) <35
Lower secondary level m 2.2
Upper secondary level m 5.2
Shuozhou Power Plant Operation Data
Ultra low emission of the power plant
NOx emission mg/Nm3 (dry,6%O2) ≤50
SO2 emission mg/Nm3 (dry,6%O2) ≤35
Dust emission mg/Nm3 (dry,6%O2) ≤5
Emission limit for the power plant
Summary of the boiler operation
Boiler operation parameter of the water and steam side is perfect to the design value; The difference of metal temperature in water wall and partition wall(wing wall) is limited in 30 ℃(20℃), and the metal temperature is safety;
Operation bed pressure in the furnace is about 7~8kPa(10kPa),pressure head of the primary air fan is low compare to the 300MW calss CFB boiler, so the auxiliary power is lower; NOx emission is lower than 300MW calss CFB boiler.
The reasons of this phenomenon Bed temperature is lower; The level of the secondary air is higher;
Problems in boiler operation
The difference of bed temperature between the center part and the side part is more than 60 ℃;
The reasons of this phenomenon Pressure drop of the air grid is not enough; By the influence of primary air inlet mode.
Problems in boiler operation
The tubes of platen reheater are damaged during the boiler operation;
The reasons of this phenomenon The width of the platen is about 4m;
The maximum metal temperature difference is
more 100℃;
What is the shape of the heat flux profile along depth of the furnace ?