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



Shanghai boiler technical characteristics


Platen superheaters, platen reheaters and wing wall are designed in the furnace.



Rolling ash coolers are used. Bottom ash discharge opening are located at the air grid.





Harbin boiler technical characteristics


Platen superheaters, platen reheaters and wing wall are designed in the furnace.



Rolling ash coolers are used. Bottom ash discharge opening are located at the bottom of the rear wall.



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


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


Boiler was designed and manufactured by Dongfang boiler

Guojin Power Plant Operation Data

Load MW 352 Fuel Gangue

Main steam temperature ℃ 567


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










SO2 emission mg/Nm3 (dry,6%O2) <35




Unburnt Carbon in fly ash % 2.58

Unburnt Carbon in bottom ash % 1.8

Hequ Power Plant Operation Data



Load MW 350 Fuel Anthracite






NOx original emission mg/Nm3 (dry,6%O2) 120





Unburnt Carbon in fly ash % 7

Unburnt Carbon in bottom ash % 2.1

Hepo Power Plant Operation Data



Load MW 349 Fuel Bituminous









Upper secondary level m

Unburnt Carbon in fly ash % 5

Unburnt Carbon in bottom ash % 2

Huamei Power Plant Operation Data


Boiler was designed and manufactured by Shanghai boiler






Oxygen content % 4

NOx original emission mg/Nm3 (dry,6%O2) 140



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 ?

Thank you for your attention!

Zhang Man

Tsinghua University, China

April, 2016, 72nd IEA-FBC, Budapest, Hungary

design and operation of 350mw cfb boiler in china man... · 350mw cfb boiler general arrangement...

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