boiler mannual

7/28/2019 Boiler Mannual

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INSTRUCTION FOR

PRODUCTBTG for Chhattisgarh 4X135

MW CPP, Raigarh

DOCUMENT NO.: 573-1-8601 - I -

DESEIN PRIVATE LIMITED

BTG for Chhattisgarh4 X 135 MW CPP, Raigarh

INSTRUCTION FOR PRODUCT

DOCUMENT NO.: 573-1-8601

REV. 0

JINDAL STEEL AND POWER LIMITED

SHANGHAI BOILER WORKS LTD.No.250 Huaning Road,

Minhang Shanghai,China

SHANGHAI ELECTRIC GROUP Co., Ltd.,No.8 Xingyi Road,Shanghai,China


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INSTRUCTION FOR

PRODUCTBTG for Chhattisgarh 4X135

MW CPP, Raigarh

DOCUMENT NO.: 573-1-8601 - II -

DOCUMENT CONTROL SHEET

PROJ ECT: BTG for Chhattisgarh 4 X 135 MW CPP, Raigarh

CLIENT: JINDAL STEEL AND POWER LIMITED/ SHANGHAI

ELECTRIC GROUP Co., Ltd.,

DOCUMENT TITLE: INSTRUCTION FOR PRODUCT

DOCUMENT NO. : 573-1-8601

REV. NO. : 0

ENDORSEMENTS

0 2009.3.30

REV.NO.

DATE DESCRIPTIONPREP. BY

SIGN.(INITIAL)REVW. BY

SIGN.(INITIAL)APPD BY

SIGN.(INITIAL)


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INSTRUCTION FOR PRODUCT

SG-460/13.7-M573

MODEL OF PRODUCT

460t/h Circulating Fluidized

Bed Boiler

NAME OF PRODUCT

573-1-8601

SERLES NO.

PREPARED BY DATE

CHECKED BY DATE

REVIEWED BY DATE

APPROVED BY DATE

SHANGHAI BOILER WORKS, LTD.


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Catalog

0 INTRODUCTION..4

1 BOILER BASIS AND PERFORMANCE DATA..4

1.1 BOILER MODEL AND TYPE..4

1.2 BOILER TECHNICAL DATA...4

1.3 EXPECTED MAIN PERFORMANCE OF STEAM GENERATOR ( AT B-MCR OF DESIGN

COAL..5

1.4 FUEL..5

1.4.1COAL SPECIFICATION..5

1.4.2OIL FOR IGNITION AND AUXILIARY FIRING..6

1.5 STEAM AND WATER QUALITY7

1.6 SITE CONDITION.7

1.7 BOILER WORKING CONDITIONS...7

1.8 BOILER WATER VOLUME(M2)....8

2 BOILER OVERVIEW AND CONSTITUENT SYSTEM8

2.1 OVERALL BOILER INTRODUTION.8

2.2 STEAM AND WATER SYSTEM..11

2.2.1 FEEDWATER AND STEAM-WATER RECIRCULATION SYSTEM ( DRAWING 2.2.1;

DRAWING 2.2.2)12

2.2.2SUPERHEATED STEAM SYSTEM ( DRAWING 2.2.3 )13

2.2.3REHEAT STEAM SYSTEM ( DRAWING 2.2.4 )16

2.3 COMBUSTION SYSTEM17

2.3.1FUEL CRUSHING SYSTEM17

2.3.2COAL EXTRACTOR FEEDER AND CHUTE.17

2.3.3START-UP OIL IGNITOR..18

2.4 GAS AND AIR SYSTEM19

2.5 LIMESTONE AND BED MATERIAL SYSTEM.20

2.6 ASH RECIRCULATION SYSTEM..21

2.7 BOTTOM ASH EXTRACTION SYSTEM.21


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2.8 TEMPERATURE CONTROL SYSTEM22

2.8.1SUPERHEATED STEAM TEMPERATURE CONTROL SYSTEM ( DRAWING 2.8.1 )...23

2.8.2REHEAT STEAM TEMPERATURE CONTROL SYSTEM23

2.8.2.1 EMERGENCY SPRAY WATER..23

2.8.2.2 GAS TEMPEARATURE CONTROL DAMPER..25

2.9 PIPING SYSTEM25

2.9.1PIPING FOR DRAINAGE, CHEMICAL FEED, REGULAR BLOWDOWN AND ACID

W A S H . 25

2.9.2PIPING FOR VENT, SAMPLING AND NITRIGEN INJECTION..26

2.9.3CONTINUOUS BLOWDOWN PIPING26

2.9.4SAFETY VALVE VENT PIPING..27

2.10MEASURING POINTS ARRANGEMENT..27

2.10.1 STEAM WATER SYSTEM MEASURING POINTS ARRANGMENT..27

2.10.2 GAS AND AIR SYSTEM MEASURING POINTS ARRANGMENT28

2.10.3 THERMAL CONTROL DESIGN DATA..28

2.11SOOTBLOWING SYSTEM..29

2.11.1 SOOTBLOWER ARRANGEMENT OVERVIEW29

2.11.2 SOOTBLOWER PIPING29

2.11.3 PROGRAMED CONTROL OF SOOTBLOWER..29

3 MAJOR PARTS..30

3.1 STEAM DRUM AND INTERNALS.30

3.2 WATER-COOLING SYSTEM30

3.3 REAR PASS HEAT-ABSORBING SURFACE.31

3.4 CYCLONE AND SEAL POTERROR

3.5 ASH COOLERERROR

3.6 BOILER FRAMWORK AND PLATFORMS & STAIRS33

3.7 SUPPORT AND HANGING FOR PRESSURE PARTS33

4 OTHER SYSTEMS..34

4.1 PROTECTION AGAINST ABRATION.34

4.2 SEALING.35


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0. INTRODUCTION

Circulating fluidized bed (CFB) combustion is a new kind of high efficient, low

pollution clean coal combustion technology. The main feature of it is that the furnace

contains a large mass of bed materials. In the combustion process, these materials are

carried to the upper furnace by gas flow, separated from gas by the cyclones

connected to the furnace outlet and conveyed to the bed through non-mechanical

return valves. Thus realizes repeatable combustion of these materials. These materials

have a high density, large heat capacity and are well mixed and usually each kilo gas

can carry several kilo materials. Hence a high thermal coefficient of bed materials, a

wide range of boiler load and a large flexibility with respect to fuel quality. CFB

technology adopts a higher fluidizing speed than bubbling bed, so there is not an

obvious bed plane as is in the bubbling bed. Because of the turbulent flow and

recirculation of bed materials inside the bed, which enlarge the residence time of the

fuel, CFB has a higher combustion coefficient than the bubbling bed and can run

stably under low load without any auxiliary fuel.

The working temperature of CFB is usually between 850-900, an ideal range

for desulfurisation. In-Furnace Desulfurization technology is adopted. Limestone and

desulfurizer are fed into the bed. As the fuel and desulfurizer recirculate, repeating

low temperature combustion and desulfurization, at Ca/S circa 2, the desulfurization

efficiency can reach 90% and greatly decrease the SO2 emission. On the other hand,

CFB technology adopts stepped low temperature air supply combustion which keeps

the combustion process going under low excess air condition. Thus the produce and

emission of NOx is also greatly reduced. The CFB technology is also advanced in its

high combustion efficiency, capability of firing low rank fuel, wide range of boiler

load and convenience in ash reuse. So CFB is growing rapidly throughout the world.

As the environment protection requirement is getting more and more rigid, it is

commonly acknowledged that CFB is, so far, one of the most practical and feasible

combustion facilities.

Design of boilers of this project is made by SBWL using advanced CFB technology

based on the experience of design, manufacture and operation of tens of ultra high


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pressure medium reheat CFB boilers. When firing design coal, boiler can operate

within 70%~100% rated load at constant pressure and within 50~100% rated load at

slide pressure. SH outlet steam can remain at rated parameter. When firing design coal

or check coal, boiler can remain stable firing within 30~100% rated load

1. BOILER DESIGN BASIS AND PERFORMANCE DATA

This is an island, half-open boiler, with complete steel structure and light steel roof on

the top. It is jointly fixed by support and hanging measures. The furnace floor

elevation is 9 m above ground. Here is some of the boilers characteristics: single

drum natural circulation, confluent downcomer, balance draft, thermal insulated

cyclone gas/solids separator, CFB combustion, air and water cooled fluidized bed ash

cooler, convection heat- absorbing surface designed in rear pass, superheater with two

stages of spray water atteperators, reheater temperature controlled by gas damper and

auxiliarily by emergency spray water device.

1.1 BOILER MODEL AND TYPE

Model: SG-460/13.7-M573

Type: super-high pressure intermediate reheat, single drum natural circulation,

circulating fluidized bed boiler

1.2 BOILER TECHNICAL DATA

ITEM UNITVWO

CONDITION

T-MCR

CONDITION

SH steam flow t/h 447.4 417.9

SH outlet steam

pressureMPa(g) 13.7 13.65

SH steam outlet

temperature

540 540

RH steam flow t/h 366.2 343.1

RH inlet steam pressure Mpa(g) 2.77 2. 6

RH outlet steam Mpa(g) 2.63 2.47


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pressure

RH inlet steam

temperature

324 319

RH steam outlet

temperature

540 540

Feedwater temperature 247 245

1.3 EXPECTED MAIN PERFORMANCE OF STEAM GENERATOR (AT

T-MCR OF DESIGN COAL)

ITEM UNIT VALUE

Designed efficiency (LHV) % 81.87

guaranteed efficiency (LHV) % 81.5

Solid unburnt loss % 2.77

PH outlet dust concentration g/Nm3 50.2

1.4 FUEL

1.4.1 COAL AND ASH SPECIFICATION

135MWe CFB boiler design fuel

items description symbol unit design coal

Proximate analysis( As received basis)

1 Moisture (Total) Mar % 12.00

2

Fixed CarbonMad % 18.00

3

AshAar % 54.00

4

Volatile MatterVar % 14.00

5

Volatile Matter(dry ash free) Vdaf % 41.17


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Qnet.ar kJ /kg 88126

LHV kcal/kg 2105

Qnet.ar kJ /kg 9630

7

HHVkcal/kg 2300

Ultimate analysis(As received basis)

1

CarbonCar % 24

2

Hydrogen

Har % 2.3

3

Oxygen (by difference)Oar % 6.5

4

NitrogenNar % 0.7

5 Sulphur Sar % 0.5

6

Total % 100

Analysis of ash ( Fly ash)

1

SilicaSiO2 % 60

2

AluminaAl2O3 % 24

3

Iron oxideFe2O3 % 8

4

ManganeseMnO2 % 0.03

5

Titanium oxideTiO2 % 1.5

6

Potassium oxideK2O % 0


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7

sodium oxideNa2O % 0

8

Calcium oxideCaO % 4

9

Magnesium oxideMgO % 2

10

Sulphuric anhydrideSO3 % 0.25

11

Phoshorus PentoxideP2O5 %

12

Others% 0.22

13

Total% 100

Ash Fusion Temp. at oxidizing media

14

Initial deformation temperatureDT 1210

15

Hemi spherical temperatureST 1320

16

Flow temperatureFT 1350

Ash Fusion Temp. at reducing media

17

Initial deformation temperatureDT 1050

1.4.2 OIL FOR IGNITION AND AUXILIARY FIRING

This boiler use N0 light diesel oil for ignition and auxiliary firing. The coal

specification is as follow:


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Sl.No. Particulars Unit (IS : 1593)

1. Flash point Deg. C min. 66

2. Viscosity @ 150C Maxi. Cst 2.0 - 7

3. Pour point 0C 12

4. Ash content by weight % max. 0.02%

5. Free Water content by volume % max. 0.05%

6. Sediments by weight % max. 0.1%

7. Total sulphur by weight % max. 1.8%

8. Carbon residence (Rams bottom) % wt

9. Approximate gross calorific value Kcal/kg In the order of

11000

10. SP gravity at 150C Max. 0.81

1.5 STEAM AND WATER QUALITY

To ensure the boiler outlet steam quality, the boiler water and steam quality must be

strictly controlled, especially the feedwater quality. The boiler feedwater, boiler water

and steam quality should be accord with GB/T12145-1999, The Standard Of Water

And Steam Quality For Power Plant Facilities And Steam Powered Equipments.

1.6SITE CONDITION

The condition as follow:

Project 4 x 125 + 20 % MW Thermal Power

Plant

Owners consultant DESEIN PRIVATE LIMITED,

DESEIN HOUSE,

GREATER KAILASH II

NEW DELHI 110048

Location Village:Dongamahua,Tehsil:

harghoda,

District Raigarh

Longitude:220653to 20713


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Latitude:833145to 833226

Site Adjacent to existing coal washery of

JSPL.

Nearest Airport Domestic Raipur (350 KM)

International Kolkata

Nearest Seaport Kolkata

Nearest Railway Station Raigarh Railway Station on the

Mumbai Howrah main line 54 Km way

from the site

Access to site

Metrological data

A Altitude [Observatory] 280 m above MSL

B Ambient Temperature

I Maximum Temperature,

DBT

47.2 Deg C

II Minimum Temperature,

DBT

12.41 Deg C

III Maximum Temperature,

WBT

30.8 Deg C

IV Minimum Temperature,

WBT

20.6 Deg C

C RELATIVE HUMIDITY Varies from 19% to 85%

D RAINFALL

I. Annual Rainfall 1400 mm to 1600mm

II Tropical monsoon June to October

E WIND VELOCITY AND

PRESSURE [AS PER

IS:875-1987]

I. Basic wind speed. 50 m/sec at 10M above mean

retarding surface.

II Wind Direction North East


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III. Terrain classification Category II

F Seismic Zone Zone III, as per

IS-1893, Part 1

1.7 Boiler working conditions

aUnit working mode

It can be run following compound slide pressure mode as well as constant

pressure mode.

bLoad kind of unit

The unit is designed to meet the needs of running safely and stably on

condition that the minimum steady-state combustion load without

oil-feeding is not large than 30% BMCR

cUnit annual working mode

The annual average working hours is no less than 7500 hours

dFeedwater regulation

2110 electric adjusting speed pumps are set for the unit, one is

operating , the other is backup. Feedwater operation desk has no main

adjusting valve, the 30% BMCR starting adjusting valve is set to meet the

requirement of start and low load condition.

eBypass settings

Two stage series-connedted bypass system is used to meet the function of

quick start and working substance return. The HP bypass flow capacity

according to the 60% BMCR of steam flow. The LP bypass flow capacity

according to the HP bypass flow adding the HP bypass desuperheater flow.

The bargainor shall consider protecting RH against dry-burning.

1.8 BOILER WATER VOLUME (M3)

ECO DRUMWATER

COOLINGSH RH TOTAL

73.22 30.70 68.90 108.22 107.24 388.28

2 BOILER OVERVIEW AND CONSTITUENT SYSTEM

2.1 OVERALL BOILER INTRODUTION


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The boiler consists of steam drum, suspensory whole-membrane waterwall furnace,

thermal insulated cyclone separator, U-type seal pot duct and rear pass convection

heat-absorbing furnace. The drum, boiler water wall and rear pass cover wall are all

suspended. Cyclone and cyclone outlet duct are laid on steel beams. The primary of

economizer pipes are suspended on weight bearing girder by pipe clamps and is laid

on the steel beam through economizer frameworks column and ox leg structure.

U-type seal pot and tubular air preheater are supported by steel beams. An

independent steel structure is settled between column J and column K to support the

heavy primary economizer and tubular air preheater. Furnace and rear pass cover

superheater expands downward. There is an expansion center designed in boiler

waterwall, cyclone and rear pass respectively, the expanding parts are connected by

non-metal expansion joints. The figure of the boiler is eudipleural. Secondly span is

designed between left and right steel structure, upon which disposed platforms,

passages, economizer inlet pipes, main steam pipes, RH inlet pipes and RH outlet

pipes.

There are 2 water panels and 14 superheater screens on the upper furnace. The

panels are disposed symmetrically on left and right sides. Between the furnace and

the rear pass are two thermal insulated steel plate cyclones. The hull of the cyclone is

made of carbon steel plate. On the inner side of the hull is a layer of thermal

insulation material which is between the hull and the abrasion resistant layer. A

circular support is disposed between the cyclones column and the cone, laid on the

steel beam. Below each cyclone there is a non-mechanical U-type seal pot, at the

bottom of which there are fluidizing holes that fluidize the solids and return the solids

to the furnace. The rear pass is divided into two gas ducts by partition wall

superheater. In the front gas duct disposed the reheater, hung by superheater hanger

tubes and other hangers on the furnace top steel beams. In the back gas duct, the

high-temperature superheater (HTS) and secondary economizer is disposed

successively through the direction of gas flow. The pipes of HTS and secondary

economizer are attached to the rear wall superheater and partition wall superheater,

which transfer the load to the furnace top steel structure. In the superheater system,


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primary spray water attemperator is set between the cold end and the hot end of the

superheater screen while secondary spray water attemperator is set between

superheater screen hot end and HTS. As CFB is characterized in its little gas

temperature difference, it is unnecessary to cross and combine the pipes from left and

right, and this arrangement is more practical. Gas temperature control damper is

disposed at reheater and secondary economizer outlet to control the gas flow passing

the reheater and thus control the outlet steam temperature. Emergency spray water

system is disposed on both sides of the reheater inlet ducts. When the steam turbine

high pressure cylinder outlet temperature goes above designed parameter, the

emergency spray water system will be actuated to ensure the reheater working safely.

Two stages of air supply are used in the boiler. Primary air goes through the bed

plate at furnace bottom and fluidizing holes into the furnace. Secondary air goes from

combustion chambers cone into the furnace. There are six coal-feed holes and six

limestone feed holes symmetrically disposed before furnace. At furnace bottom, the

steel plate made primary air chamber is hung on the lower header of waterwall. On-

bed start-up ignition is used and four (2 on either side wall) powerful torch oil guns

are disposed on the bed. And there is 4 drum ash cooler at the bottom of combustion

chamber.

Circulating fluidized bed combustion is used in this boiler. Under circa 880

bed temperature, the fuel, air and limestone mix in the dense-phase zone. Fluidized

coal particles burns and gives heat. Heat transfers from high temperature bed

materials and gas to waterwall surface. Limestone is calcinated into CaO and CO2.

CaO combines with SO2, which is a product of fuel combustion, and realizes

in-furnace desulfurization. The gas containing a large mass of bed materials goes

tangentially into the two cyclones from the furnace back wall outlet and is separated

from the solids by the cyclones. Then the clean gas leaves the center cylinder of the

cyclone and passes HTS (RH), ECO in the rear pass and the air preheater and is

finally released to air with its temperature drops to about 140. The solids collected

by the separators are returned to the furnace through the vertical pipes and the U-type

seal pots, hence the solids recirculated combustion. Because the solids (ash, unburnt


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carbon, CaO and CaSO4) are repeatedly fired during the recirculation, the availability

of desulfurizer is greatly increased. The bottom ash (bottom ballast) is cooled in the

ash cooler disposed on both sides of the furnace and is discharged when its

temperature is below 150.

The mean elevation of the drum is 48220 mm. The distance from column G to K

is 37200 mm. The main span width is 21000mm and the secondary span width is

5000 mm.

2.2 Steam Water System

The steam water circulation system includes back pass economizer, drum,

generating surface (boiler water wall and water wall panels), back pass enclosure SH,

cold and hot platen SH, high temperature SH and RH.

2.2.1 Feedwater and Steam Water Circulation System (drawing 2.2.1,

drawing2.2.2)

There are 2 electric adjusting feed pumps, and the capacity is designed according

to 100%BMCR. The total 2 circuits are set for feed water: a DN225 main feedwater

duct with an electric gate valve and a non-return valve; a DN100 bypass feedwater

duct with an adjusting valve and 2 shut-off valves. When the boiler load is within the

30-100%BMCR, use the adjusting feed pump to control the feedwater; when the

boiler load is lower than 30%BMCR, switch to the bypass feedwater duct and use the

feed adjusting valve to control the feedwater.


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Fig 2.2.1 feed water system

C1drum

E1ECON inlet tube

E2Low temp. ECON inlet header

E3Low temp. ECON

E4Low temp. ECON outlet header

E5ECON duct connection

E6: High temp, ECON inlet header

E7High temp. ECON

E8High temp. ECON outlet header

E10ECON riser tube

E11ECON recirculating tube


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fig. 2.2.2 steam water circulating system

C1drum C2collective downcomer

C3C4C5C6water wall lower header

C7C8C9C10water wall tubes of furnace

C11rear wall outlet ring header

C12C13water wall upper headerC14water wall downcomer

C15water wall inlet header: C16water wall tubesC17water wall outlet heade

C18C19water wall steam-water riser tube


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Firstly the feedwater flows from one side of the boiler into the primary

economizer inlet header. Secondly it flows upstream through 2 horizontal-arranged

economizer ducts. Thirdly after it is heated, it flows into the second stage economizer

ducts. Finally it converges at the economizer outlet header, and then flows through 2

connecting ducts into the drum. One economizer recycle duct with 1 electric shut-off

valve and 1non-return valve is set between the drum and the header at the primary

economizer inlet. When the boiler is starting up, turn on the electric shut-off valves in

the duct. A natural circulation circuit is established between the economizer and drum,

which prevents the dead water evaporation in the economizer and assures the safety of

the economizer when the boiler is starting up. When the feedwater is enough, the

electric shut-off valves in the duct can be shut off. The recycle duct capacity is

designed according to 5%BMCR.

The steam water circulation system includes drum, big diameter downpipes,

water wall panel downpipes, water wall, water wall panels and lead-out ducts. The 4

356 big diameter downpipes leaded from the water space of the drum are connected

with the lower headers of water wall at the front, left and right furnace walls

separately. According to the combustion characteristics of CFB, the heat load

distribution in the furnace is very homogeneous. So the separating circuit is not set in

the water wall design, and the tee junction is used to connect the lower headers of

water wall into a ring circuit and the inside medium is connected. The water wall is

made of membrane wall containing 63.5bare tube and flat iron. The boiler water is

continuously heated when it flows up along the membrane waterwall, and the

steam-water mixture is formed gradually. The steam-water mixture flows from the

headers at the upper outlet, and then it flows through 36 168 steam-water lead-out

pipes to the drum. At the same time, the water is supplied from 2 219water wall

panel downpipes leaded from the water space of the drum to 6 water wall panels at the

upper of the furnace. The steam-water mixture formed in the water wall panel flows

through 4 168 steam-water lead-out pipes to the drum. The steam-water mixture

is well separated in the drum by cyclone and corrugated plate. The separated water

goes into the drum and water circulation again, and the purified steam goes into the

SH system by steam-water lead-out pipes at the furnace roof.


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The circuits of water wall and water wall panels are two separated parallel ones,

and the flow distribution between them depends on their own surfaces, furnace heat

load and water circulation coefficient. Once the flow distribution is determined,

specifications and quantities of downpipe and lead-out pipe can be selected according

to the outcome of water circulation calculation. Thus, the reasonable water circulation

coefficient is guaranteed, and the water circulation is stable and reliable.

2.2.2 Superheated Steam System (drawing 2.2.3)

The saturated steam leads out from the top of the drum, and it flows through 8

168 connecting ducts into the header above the left and right side enclosure SH.

Secondly it flows into the header under the side enclosure SH. Thirdly it convergesthrough header at the header under the front enclosure SH. Fourthly it flows

through front enclosure SH, roof enclosure SHrear enclosure SH, parallel-arranged

pendant tube SH and division wall enclosure SH. Fifthly it converges at the header

above the division wall enclosure SH. Sixthly it flows through 2 273 connecting

ducts into the header at the inlet of cold panel SH. Seventhly it is heated when it flows

along the heating surface and then flows into the primary attemperator. Eighthly it

flows into the hot panel SH, and then it is attempered by the second stage attemperator.

Ninthly, it flows through 2 324 connecting ducts into the high temperature SH in

the back pass and is heated to the required temperature. At last it flows through the

main steam duct from the header at the outlet of the high temperature SH into the

high-pressure tank of the steam turbine. The flow of steam is as flows:

saturated steamleft and right side enclosure SHfront enclosure SHroof

enclosure SHrear enclosure SHdivision wall enclosure SH, pendant tube SH

cold panel SHprimary attemperatorhot panel SHrear panelsecond stage

attemperatorhigh temperature SHmain steam outlet


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fig. 2.2.3 SH steam system

S1saturated steam riser tube S17primary SH inlet header

S2clad side wall upper header S18primary SH panel tube

S3clad side wall tube S19primary SH panel middle header

S4clad side wall low header S20primary SH panel tube

S5clad front wall low header S21primary SH panel outlet

S6clad front wall tube S22primary desuperheaterS7clad front wall upper ring header S23secondary SH panel inlet header

S8S9clad roof & rear wall tube S24secondary SH panel tube

S10clad rear wall low header S25secondary SH panel middle header

S11connecting pipe S26secondary SH panel tube

S12partition low header S27secondary SH panel outlet header

S13partition tube S28secondary SH outlet header tee

S14hanger tube S29secondary desuperheater

S15partition wall upper header S30high temp. SH inlet header

S16connecting pipe S31high temp. SH tube

S17primary SH panel inlet header S32high temp. SH outlet header


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S33high temp. SH outlet connecting pipe

2.2.3 Reheated Steam System (drawing 2.2.4)

The steam discharged from the high-pressure tank of the steam turbine flows

through 2 426connecting ducts into the RH. The RH is arranged in one stage,

which comprises 4 sets of tube. All sets are arranged in the front duct of back pass and

are suspended on the SH pendant tube. The reheated steam is heated and flows

through 2 457 connecting ducts into the inter median cylinder of turbine. An

emergency attemperator is set on the duct of RH inlet. When the temperature of theexhausted steam from HP cylinder of turbine is higher than the design value, the

emergency attemperator will be started to lower the temperature of reheated steam

and thus guarantee the safe operation of RH. The temperature of reheated steam is

attempered by flue gas baffle at the outlet of back pass.

Fig 2.2.4 RH steam system


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R1R2RH emergency spray R5RH outlet header

R3RH steam inlet pipeRH inlet header R6: RH steam outlet pipe

R4RH tube

2.3 Burning System

2.3.1 Fuel Crushing System

Raw coal is crushed through two stage crushers. The requirement of grain size at

the outlet of the last-stage crusher is seen in Drawing 2.3.1. Raw coal with the eligible

final grain size goes into the big coal bunker, and is conveyed by a coal feeder to the

above of coal chute. The sweeping air is set under each coal chute so that the coal can

be fed into the furnace homogeneously.

2.3.2 Coal Feeder and Coal Chute

Six coal feeders are arranged in front of furnace. They connect the big coal

bunker and coal chute and convey the crushed coal to the inlet of coal chute according

to the boiler load requirement. Considering the repair of coal feeder and fuel change,

the feeder design capacity should have 100% reserve margin.

In the coal chute, the coal arrives at the feed port of furnace by gravity, and

finally goes from the front water wall into the furnace. The sweeping air is provided at

the feed port of furnace so that the air cushion can be formed in the duct and at the

turning corner of duct. It makes coal flow fluently, have some kinetic energy and

distribute evenly, and it prevents coal local piling. The material of coal chute is

stainless steel tube material of 45710mm, and the lower part of it is the ceramic

lining tube of internal diameter 433mm, which prevents coal clogging. Expansion

joint is set on the perpendicular section of coal chute. It absorbs the heat displacement

of water wall and the heat displacement is as follows:

Item UnitFeed

port#1

Feed

port#2

Feed

port#3

Feed

port#4

Feed

port#5

Feed

port#6

Down

mm 140 140 140 140 14014

0

Front of Furnacemm 20 20 20 20 20 20

Leftmm 28 18 7 / / /


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Right

mm / / / 7 18-2

8

Note: The feed ports are numbered from left to right, and the expansion center of

boiler takes the symmetrical centerline of boiler as origin.

To prevent backflow of gases from the furnace to the coal feeder, a cold air, used

as sealing air to protect the coal feeder, should be leaded from the cold air duct at the

outlet of primary air fan to the coal feeder and coal chute. The inlet of coal feeders

sealing air is set at the inlet of coal feed, and the inlet of coal chutes sealing air is set

under the sluice valve.


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2.3.3 Start-up Oil Burner

There are 4 above-bed start-up burners (the capacity is 43000kg/h) in the boiler.

The oil gun is the one with pressure air atomization, center return flow oil, wide

control band and convenient operation. The pressure of main line feeding oil is

1.8MPa and the flow is 12t/h. The oil system at the front of furnace takes the

pressured air as the sweeping medium, and the sweeping pressure is 0.75MPa and the

temperature is 250.

The ignition oil gun is the advance and retreat type one and there is some space

between gun and anti-abrasion sheet surface inside the furnace. When the boiler

operates normally, the above-bed ignition oil gun can be retreated to the outside of

furnace. At the same time, certain amount of cold air is maintained, which prevents

burners burnout. The high energy arc ignition device and flame detector are supplied

with the above-bed ignition oil gun.


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When the boiler starts up coldly, the start-up bed material is put into the CFB.

Firstly turn on the primary air fan and make bed material little fluidized. Secondly

turn on the secondary air fan, put the ignition oil gun into use and heat bed material

according to the start-up chart. Thirdly after the bed temperature increases to 620C

and keeps stable, feed the coal to guarantee the reliability of ignition. During the coal

feeding, small amount of coal is fed at interval at first. And after the coal is fired, feed

more coal and start the feed device continuously.

2.4 Flue Gas and Air System

The boiler is a balance draft one, and the pressure zero point is set at the inlet flue

gas duct of cyclone. The circulation of material in CFB is started and maintained by

FD fan (including primary and secondary air fan) and ID fan. The combustion air

from the primary air fan goes through the air heater and primary air preheater in line

and then splits in three parts: the 1st one is as fluidizing air that goes into the air

plenum at the furnace bottom and through the furnace capped nozzles, and it fluidizes

the material on the bed and forms the upward solid circulation; the 2nd one is as

sweeping air extracted through a trunk duct from the air plenum to the front of

furnace and then 6 branch ducts from the trunk duct to the coal chute, and the total

flow is 18600Nm3/h; the 3rd one is a high pressure cold air extracted from the cold

air duct behind the outlet of the primary air fan as sealing air for coal feeder and coal

chute, and the total flow for coal feeder is 2520Nm3/h and the total flow for coal

chute is 672Nm3/h. The secondary air is heated when going through the air heater and

primary air preheater in line, and then it is leaded to the front of furnace. Several

branch ducts leaded from the air plenum goes from the upper of front, rear wall and

emulsion zone of furnace to the furnace firing chamber. It is also used as cooling air

for oil gun. When the boiler load is 100%B-MCR, the proportion between primary air

and secondary air is about 55:45. When the boiler load decreases gradually, the

proportion between primary air and secondary air changes accordingly and the

proportion of primary air increases gradually. The details are seen in Collection

Chart of Boiler Thermal Calculation.

The flue gas with solid particles goes through the inlet duct of cyclone from the

furnace into 2 cyclones tangentially. In the cyclone, coarse particles are separated

from flue gas, and the flue gas goes through the cyclone into the back pass. The flue


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gas is cooled by the convection heating surface. Then it goes through the tubular air

preheater into the dust collector and fine particles are left out of flue gas. Finally it is

sent into the stack by ID fan and discharged to the atmosphere.

One portion of high pressure fluidizing air is used as fluidizing air for U seal pot;

the other one is used as greasing air for erect duct and return duct of seal pot. One

portion of FBAC fluidizing air is used as fluidizing air for FBAC; the other one is

leaded to the outlet of furnace slag-drip opening and used for sweeping tapered valve

hood at the top of slag-drip valve shaft. It assures the smooth feeding of FBAC.

2.5. Bed material system

Start-up bed material feed-hole is designed at anabatic vertical pipe of two

U-type seal pots, start-up bed material bin is arranged in boiler proper structure, the

height of strat-up bed material bin shall be above the level of start-up bed material

feed-hole, to ensure bed material can flow into seal pot of itself. Start-up bed material

bin is also arranged at front of furnace and connected with feeder, bed material is

filled into furnace by using feeder and feed chute. Start-up bed material is usually

adopt sand, or adopt coal ash is burned off, grain requirement of bed material see

2.5.2 bed material grain distribution.


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Bed material injection quality is 13600kg before boiler start-up, including bed

material for furnace, seal pot and ash cooler. If CFB slag as bed material in furnace,

the height is about 880mm; if bed material is sand, the height is about 760mm.

2.6 Ash circulation system

Ash circulation system is composed of furnace, cyclone and U-type seal pot.

Primary air enter into emulsion zone at furnace bottom through nozzle arranged at

water-cooled air distributor, to make material in furnace fluidize, HT material, coal

and limestone mix completely, and complete burn and desulfurize in emulsion zone.

Large grain material flow into emulsion zone along boiler water wall after it is

fluidized and suspend at certain height; small grain material leave furnace carried by

flue gas, tangential enter into cyclone with high speed through nonprismatic cyclone

inlet duct. Flue gas rotate with high speed in cyclone, solid grain that its quality is


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large is thrown cyclone inside wall because of centrifugal force effect and flow into

seal pot along inside wall, but small solid grain enter into boiler back pass by flue gas

through vortex at cyclone upper. Cyclone design is adopted ALSTOM company

mature and advanced technology, separate rate is more than 99.5%, can separate HT

solid material from gas flow, then enter into furnace through seal pot to maintain high

grain concentration in furnace and ensure large heat surface heat-transfer rate, ensure

that fuel and desulfurizing agent can completely burn off and chemical react in

multi-circulation. Truly materialize CFB boiler high efficient and clean combustion

technology.

Ash circulation ratio is about 30, bed pressure in furnace emulsion zone can

reflect furnace ash concentration indirectly, control ash concentration at reasonable

level by ash discharge at furnace bottom.

2.7 Tapping slag and ash discharge system

Ash content of coal is discharge as slag at furnace bottom and as fly ash at boiler

back-end. The quotient of each kind of ash content is different according to coal

granularity, ashing feature. Based on this boiler design coal and coal granularity into

furnace, slag is 45% in total ash, mean granularity is about 500um, fly ash is 55% in

total ash, mean granularity is about 30um.

Four ash coolers is arranged in this boiler, set at the furnace bottom and arranged

at 0m layer, adopt water cool as main cooling form. The total ash of boiler is .

16091kg/h, The designed ash discharge amount of each ash cooler is 50% in total ash.

Only one ash cooler can meet the needs of normal operation for boiler. The feed slag

temperature is 880, and the tapping spout temperature is 110.

2.8 Attemperation system

2.8.1 SH steam attemperation system


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fig 2.8.1 SH steam attemperation system

SH steam attemperation system is divided into two stages. Primary spray

desuperheater is arranged between cold end outlet and hot end inlet of platen

superheater to control steam temperature into hot end inlet of platen superheater.

Primary desuperheater is one, proper size is32428, material is SA335-P12,

spray tube adopt flute-type structure. Secondary spray desuperheater is arranged at

connection pipe between hot end outlet of platen superheater and HT superheater inlet

to control steam temperature of HT superheater outlet, and make SH steam


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temperature attain design value. Secondary desuperheater is two, proper size is324

28, material is SA335-P12, spray tube adopt flute-type structure. Water source of

desuperheated water is introduced to the front of HP heater and feedwater operation

platform, the max. spray water amount in this system has been considered

desuperheated water amount needed in high preesure heater out of servicedrawn

point temperature of desuperheated water is 172, pressure is about 16Mpa(g) under

B-MCR condition.

See drawing 820573-E1-06 (superheater desuperheated water pipeline), the

interface position of desuperheater water pipeline and design institute is at the front of

column G. adopt reducing tee to divide into three branch pipe at the end of

desuperheated water manifold, one cutout valve is set at each branch pipe, this valve

can be closed under boiler emergency condition to separate electric control valve

behind it. Set another cutout valve behind electric control valve, close this valve when

control valve is maintained. Set one drainage (backwash) pipeline between cutout

valve and control valve, can termly check cutout valve is leakage under closed

condition or not. Spray water control valve adopt imported produce, can meet the

requirement under various conditions of boiler.

Flow nozzle is set at each branch pipe of desuperheated water pipeline.

2.8.2 RH steam attemperation system

Gas tempering damper is main in RH steam attemperation, emergency spray

water is only used at non-normal condition, and viz. emergency spray water is used

when RH steam inlet temperature is higher than design value to ensure reheater safety

2.8.2.1 Emergency spray water

Two emergency spray water devices are apart arranged at left and right side pipe

of heater inlet, water source comes from pump pigtail, the pressure is about

6.0Mpa(g), temperature is 172 under B-MCR condition. At desuperheated water

manifold, adopt reducing tee to divided pipeline into two parallel circuits, and apart

enter into emergency desuperheated spray water desuperheater at two sides of boiler.

One cutout valve is set at each branch pipe; this valve can be closed under boiler

emergency condition to separate electric control valve behind it. Set another cutout


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valve behind electric control valve, close this valve when control valve is maintained.

Set one drainage (backwash) pipeline between cutout valve and control valve, can

termly check cutout valve is leakage under closed condition or not. Spray water

control valve adopt imported produce, can meet the requirement under various

conditions of boiler. Flow nozzle is set at each branch pipe of desuperheated water

pipeline This system sees drawing 2.8.2.

Fig 2.8.2 RH spray desuperheater system

2.8.2.2 Gas tempering damper


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Gas tempering dampers are apart arranged below reheater duct and HT

superheater duct, gas damper in every duct is divided into left and right group, 4

groups in all, the type is separating-chamber. Damper of every group at reheater side

is composed of 7 pieces of blade; at superheater side is 3 pieces of blade, and

combined by the tie rod. The tie rod is laid upon the damper to avoid abrasion. The

damper is controlled by the electric actuator via the tie rod; Control the damper

according to the following suggestions:

(1) Limiting position protection: the limiting inclination () of the damper and

level is 15. (damper close completely is 0 )

(2) Operation with normal load: the damper regulates the temperature of the

reheated steam. When regulating, the damper of the RH flue gas duct and SH flue gas

duct should be turning at the same time but in the opposite direction, and the sum of

these two dampers angle should be always kept as 90.

Gas quotient of duct of reheater side under various load condition sees boiler heat

calculation data sheet.

(3) The blow stage before the boiler start-up: The dampers of gas flue are

completely opened.

(4) The start-up stage: is 15at the RH side and 75at the SH side, so most

flue gas flow through the cold SH. This can not only protect the RH, but also increase

the temperature of the superheated steam quickly, and then reduce the start-up time.

2.9 piping system

Boiler piping system is mainly composed of drainage, blowdown, vent,

exhaust, etc. pipeline with related pipe and valve.

2.9.1 Drainage, periodic blowdown chemical feed , acid wash pipeline17 lines are set in boiler drainage pipeline in all, viz. economizer inlet pipe 1,

economizer outlet header 2, ring lower header under enclosure front wall 2, both ends

of lower header under enclosure rear wall 2, medium header of platen superheater

cold end 1, medium header of platen superheater hot end 1, HT superheater inlet

header 2, pipe at superheater outlet 2, reheater inlet 2, reheater outlet 2, 2 cutout

valves are set in each pipeline in series, valve adopt DN20. all drainage pipeline is

connected to boiler operation layer.

4 periodic blowdown lines are arranged at water wall ring lower header, one


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periodic blowdown pipeline is set at every water wall panel lower header. Every

pipeline is arranged with 1 imported electric periodic blowdown valve, in series with

one cutout valve before it, can close cutout valve under boiler emergency condition to

isolate electric periodic blowdown valve. Finally, above 6 periodic blowdown pipeline

converge in periodic blowdown manifold header, manifold header outlet is arranged

with high pressure difference throttling valve and electric periodic blowdown valve in

series to reduce inlet and outlet pressure difference of blowdown valve, to improve

the condition at operation, and to extend its life. The quality of the steam and water in

operation is controlled by continuous blowdown. Only when the boiler first start-up or

start-up after overhaul, or the continuous blowdown cannot maintain the quality of the

steam and water by some reasons, the periodic blowdown system will be turned on.

The support and suspender of the periodic blowdown duct should be designed

properly and meet the requirements of the expand displacement and the periodic

blowdown duct wont oscillate when it is turned on.

Besides above normal drainage, another emergency drainage pipeline is set in

boiler, introduced boiler operation layer from drum bottom. Pipeline is arranged with

two DN3electric cutout valves, immediately open this valve when drum water level

exceed normal level, after reach normal level, close the valve. Chemicals feed

pipeline is arranged at the front of boiler, connected to drum front of bottom, one

non-return valve and one cutout valve are arranged in series in this pipeline. One acid

wash pipeline is set at waterwall front and rear wall header.

2.9.2 Vent, nitridation ,samplingpipeline

10 vent pipelines are set between economizer and HT superheater, 2 vent

pipelines are set at reheater outlet, and 2 cutout valves in series for every pipeline.

There is 10 nitrogen injections in all set at economizer outlet pipe, saturated steam

riser tube, the connection pipe between clad SH and platen SH, primary stage

desuperheater, connection pipe between platen superheater and HT superheater and

reheat outlet pipe, nitridation pipeline is set between two cutout valves of vent

pipeline, 1 cutout valve is arranged at each pipeline.

Shall open vent valve and drainage valve before boiler ignition, close vent valve

and part drainage after having certain pressure, dont close superheater vent valve

until unit is on-line, avail to control main steam temperature and pressure, close

reheater vent valve and drainage valve before condenser in vacuum.


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Nitridation pipeline is for boiler shutoff for long time (exceed one month), boiler

adopt nitridation or other method. Boiler shall be draughty when filling nitrogen or in

nitridation maintenance period.

It is 8 lines for boiler sampling, viz. sampling of feedwater, boiler water, saturated

steam, SH steam and RH steam. Feedwater sampling is set at feedwater manifold,

boiler water sampling is set at continuous blowdown pipe at drum both ends, 2 points

are set at steam riser pipe for saturated steam sampling, 2 points of SH steam is set at

HT SH outlet pipe, two cutout valve are arranged at each pipeline.2 points are set at

RH inlet pipe for RH steam sampling, one cutout valve is arranged at each pipeline.

2.9.3 Continuous blowdown pipeline

The continuous blowdown converge in one line after it is connected from the

downside of the drum both ends, mainly for controlling and keeping boiler water

quality, the capacity of blowdown shall accord to boiler water chemical analysis.

Continuous blowdown pipeline is arranged with one imported air-operated valve,

another high pressure difference control valve in series to reduce the pressure

difference of the periodic inlet and outlet of the air-operated valve, to improve the

condition at operation, and to extend the life. The front and back of air-operated valve

are also arranged with one electric cutout valve while set bypass for air-operated valve

service

2.9.4 Safety valve discharging pipe

Overpressure protection of boiler pressure part is realized by setting certain

safety valve. There are 3 safety valves for SH steam system, thereinto 2 valves for

drum, one for superheater outlet pipe, additionally set 2 EBV valves in series at

superheater outlet pipe (each for left and right). pipe. There are 4 safety valves for

RH steam system, thereinto 2 valves for reheater inlet pipe, 2 valves for reheater

outlet pipe. There are 9 silencers in all according to connection meeting minutes

requirement to design silencer and discharging pipe, thereinto 2 silencers for drum

safety valve, one for superheater safety valve, two for superheater EBV valve, 2 for

reheater inlet safety valve, 2 for reheater outlet safety valve. All discharging pipes are

connected from safety valve to boiler roof upper side.

2.10 Measuring point

2.10.1 Measuring point arrangement for steam-water system

Whole steam-water system is arranged with various function instrument

measuring points according to different part and requirement. Besides local


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monitoring pressure gauge, other pressure measuring points of steam-water system

shall be arranged with primary valve, the owner can set control instrument according

to requirement, 5 pressure measuring points for drum, two of these for local

monitoring. SBWL supply whole set of valve and pressure gauge, other pressure

measuring point is supplied with primary valve, the owner can introduce to anywhere

according to checking, protection, adjustment etc. requirement.

It is necessary condition that keep boiler normal water level for natural circulation

boiler safe operation. Usually set certain number water gauge for monitoring method.

This boiler adopt dual-color water gauge arranged at drum both end head as for water

level local monitoring, the visual height of water gauge is 550mm, one TV monitor is

set prior to each water gauge, can interlaced monitor water level of drum both ends by

switching device. One electric connecting point water gauge set at drum left head is

for water level monitoring and alarm. Boiler phase-down automatically (see sheet

2.10.1) when water level exceed protection limit value. Additionally one high level

electric connecting point water gauge is arranged at drum right side head, besides

have effect as water gauge at left side head, also can meet drum full water level

checking requirement when boiler shutoff.

Sheet 2.10.1protection limit value for drum water level control

Level mmBelow drum

Centerline

150

50 100 150 175 230

Measuring

point for

Thermal

control

interlock

Normal water

level

Allowable

water level

Audible

alarm

Emergency

discharge

Phase-

down

Phase-

down

4 water level balance vessels is set at head of drum both ends for checking, protection

and adjustment under boiler operation.

Drum is very important pressure part for boiler; boiler start-up and shutdownspeed will affect drum thermal stress amplitude, so affect drum life breakage, and so


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control start and shutdown speed according to the requirement of boiler start-up and

shutdown curve strictly. 4 couples outside wall temperature measuring points and 2

couples inside wall temperature measuring points are arranged along drum axes

direction, avail to monitor drum wall temperature difference under boiler start and

shutdown. The temperature difference between drum upper wall and below wall is not

less than 50 and same as to inside wall and outside wall when boiler cold start.

2.10.2 measuring point arrangement for gas and air system

Besides gas temperature, pressure, sampling measuring point as same as

pulverized fuel boiler are arranged at CFB boiler, also set a lot of furnace pressure

difference, bed temperature, fluidizing air pressure, air flow measuring point to

provide needed monitoring method and protection measure, and to ensure boiler

safety operation.

6 couples gas pressure difference measuring point are apart set furnace below,

medium upper and primary air box, pressure transmitter convert pressure signal into

electric signal, connect with slag valve actuator at ash cooler inlet. Slag valve actuator

will operate; quicken tapping slag to make furnace bed pressure keep in regulated

range when furnace pressure difference exceeds set value. Additionally set 4 pressure

measuring points and 8 pressure switches interface in furnace, furnace pressure set

value is +20.8KPa, -8.7KPa, subatmospheric pressure zero is set at furnace outlet. 2

gas pressure measuring points are set in cyclone outlet duct, can measure cyclone

resistance loss. 2 pressure measuring points for material level are set every seal pot

vertical pipe to monitor material level in vertical pipe and alarm when material level

is too high or too low.

22 gas temp. measuring points are set in furnace, 8 gas temp. measuring points

are set in cyclone inlet duct and outlet duct in all, these measuring points are in HT,

high speed and high ash concentration zone, so shall select wear-resisting

thermocouple to ensure certain service life.

Temp. and pressure measuring point is set at all convection heat surface in rear

pass, additionally, 2 oxygen measuring points and 14 gas sampling points are set at

primary economizer outlet, 5 gas sampling points are set at air preheater outlet duct,


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design institute confirm its position.

Set enough material temp. and pressure measuring points in seal pot to ensure

material fluidize well and return to furnace successfully, and need to monitor HP

fluidizing air flow. set air flow gauge in all HP fluidizing air branch pipe and air-filled

pipe, to control air injection in design range.

2.10.3 thermal control design information

SBWL supply following information. Confirm position, range, number, use,

supply range of thermal control measuring points and alarm value and protection

value of boiler operation in these information for design institute thermal control

speciality:

P&ID drawing for boiler system

hole measuring point layout drawing

thermal control measuring point arrangement position and description

boiler control system information

information for start burner oil system at front of furnace

information for electric actuator of steam-water system valve

2.11 Sootblowing system

Reasonably set soot-blower is important auxiliary method for boiler safety and

reliable operation and to prevent heat-transfer effect due to heat surface fouling.

Sootblowing system is composed of pressure-reduction station, soot-blower,

sootblowing pipe and drainage pipe, sootblowing steam source come form platen

superheater cold end outlet pipe prior to primary desuperheater, steam pressure drop

to design value through pressure-reduction station is sent to each soot-blower.

Sootblowing steam come form auxiliary steam source system in boiler start stage,

require that steam temp260, pressure is 0.5~0.7MPa, flow 2m3/h, design

institute take charge of auxiliary steam source design.

2.11.1 soot-blower arrangement

Because boiler water wall of CFB boiler has strong capacity to clean ash by itself,

so not set soot-blower in furnace.

Only install soot-blower at convection heating surface of boiler rear pass ,


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thereinto 2 pieces of long-length retracting type steam soot-blower are installed at

under first layer tube group inlet of superheater, 2 pieces of long-length retracting

type steam soot-blower are installed at secondary economizer topper tube group inlet,

2 pieces of semi-retracting type steam soot-blower are installed at under tube group

inlet of secondary economizer. 6 pieces of long-length retracting type steam

soot-blower are installed at the topper three layer tube group inlet of reheater , 2

pieces of half retracting type steam soot-blower are installed at under tube group inlet

of reheat ; 16 pieces of land-rotary steam soot-blower are installed at under & upper

tube group inlet and front & rear wall inlet of primary economizer. 12 pieces of

half-retracting type steam soot-blower are installed at each tube group inlet of tubular

preheater.

2.11.2 Sootblowing pipe

sootblowing pipe include all equipments and pipe between superheater extraction

opening and all soot-blower, steam pressure drop regulated value through

pressure-reduction station, then enter into each soot-blower, auxiliary steam source is

connected behind pressure-reduction station. Sootblowing pipe is supplied by

soot-blower manufactory.

2.11.3 Sootblowing program control

Soot-blower program control can be realized by PLC. System can operate

automatically, remote operate and simulated operate in control room; can realize local

manual operation on site. soot-blower operate in couple according to gas flow

direction, first upstream then downstream, the longest working time of single

soot-blower is about 5min.

3. Main part

3.1. Drum and internals

drum inside diameter is 1600mm, wall thickness is 145mm, material is SA299,

straight length of shell is around 14200mm, total length including head length is about

16000mm, 4 couples measuring socket for outside wall temp. and 2 couples

measuring sleeve for inside wall temp. are set in drum wall for controlling temp.


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difference of upper and below wall in hydraulic test and operation.

Drum normal water level is set 150mm under drum centerline, the distance

between highest and normal water level is +50mm, and the distance between lowest

and normal water level is -50mm. Drum internals is composed of separator, feedwater

washing orifice plate, top uniform flow orifice plate. Separator diameter is315mm,

number is 54, connect with each connection box, deflector is installed at separator

inlet to improve steam separation effect. The capacity of single separator is about 9t/h

under B-MCR condition. Washing orifice plate is arranged above separator, it is keep

30~40mm thickness water at washing orifice plate, separated steam through washing

orifice plate cleaned by 50% feedwater came form economizer, part salt dissolve in

washing water, washed steam take uniform flow through top multi-orifice plate,

finally clean steam introduced into superheater system by saturated steam riser pipe.

Steam-water mixture is introduced from water wall and water panel into drum by

36 pieces pipes which diameter is 168.

4 pieces downcomer which diameter is356 come form drum supply water to

boiler water wall, in addition 2 pieces downcomer which diameter is219 supply

water to 2 pieces of water panel at furnace upper.

Boiler feedwater is introduced from economizer outlet header into drum by 2

connection pipe which diameter is219, 12 branch pipe which diameter is108,

thereinto 50% feedwater flow through washing orifice plate, another 50% is directly

introduced into drum water room.

Saturated steam is educed from top of drum, then is introduced into enclosure

wall superheater upper header at rear pass both sides by 4 pieces of pipe which

diameter is168.

Two spring safety valves is arranged at drum both ends, also some needed

nozzles for continuous blowdown, chemicals feed, emergency discharge, recirculation

of start and shutdown, water gauge and balance vessel are arranged at drum.

Boiler steam and water quality shall accord with the requirement of

GB/T12145-1999water and steam quality standard for heat power unit and steam


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power equipment .

3.2. Water-cooling system

furnace heightwidthdepth is 35400mm14795.5mm7683.4mm, boiler

water wall tube all adopt diameter is63.56.5, material is SA-210C tube, bare tube

and flat steel compose membrane wall, the pitch of tube is 88.9mm, arrange 166

pieces of front wall as same as rear wall, 86 pieces of tube for left side wall as same as

right wall. The excellence of membrane wall is: good sealing performance, reducing

furnace leakage, and increasing economical efficiency, wall setting structure and

support is easy and can adopt light wall setting. Multi-layer buckstay are arranged

along the height direction of boiler water wall, increase whole furnace stiffness and

keep water wall from deformity due to positive pressure combustion in furnace.

Pressure capacity of buckstay of combustion zone under furnace isnt less than

+20800KPa,-8700KPa, upper pressure capacity isnt less than 8700KPa.

Tube below rear wall is loosed, thereinto 84 pieces of tube form fluidization bed

air distributor at furnace bottom, air distributor incline is 2, another 82 pieces of

tube enter into rear wall below header. Wearing layer of air distributor level is 8200,

the pitch of water wall tube at air distributor is 177.8mm, arrange 1150 bell-type

nozzle in flat steel between water wall tube, nozzle pitch is 355.6mm and arrange in

alternation. Nozzle adopt heat-resistant and wearing stainless steel cast, can operate at

1100, has high service life.

Front and rear water wall form cone at the angle of 75 degree apart in

direction of front and rear, form combustion space emulsion zone. Open any special

hole needed by CFB boiler at below water wall in this zone, include 6 coal injection at

front wall (6 limestone injection, use one hole as coal feed) , 2 start burner for left

side wall as same as right side wall, 2 seal pot material return hole at rear wall, 1

access door for overhauling at right side wall, one furnace slag notch and one ash

cooling air-return porthole at right side wall as same as left wall, two layer that it is 18

secondary air injection in all are arranged at front and rear wall. At same time arrange

enough temperature, pressure and sampling measuring porthole in this zone.

Arrange water wall panel and platen superheater along width direction at furnace


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upper, transverse pitch is 711.2mm and 889mm, 14 pieces of platen superheater are

arranged in medium, one pieces of water wall panel are arranged in left side as same

as right side. Cold heating surface of platen superheater is composed of 38 pieces of

tube which diameter is44.55, material is SA213-T12, longitudinal pitch is

60.3mm, aggregately arrange 7 pieces. Hot heat surface of platen superheater is

composed of 38 pieces of tube which diameter is44.55.5, material is SA213-T23,

longitudinal pitch is 60.3mm, aggregately arrange 7 pieces. Every piece of water wall

panel is composed of 28 pieces of tube which diameter is63.56.5, material is

SA-210C, longitudinal pitch is 88.9mm.

Front wall turn to furnace rear and form furnace roof. Steam and water mixture

come from front wall and rear wall whole enter into rear water wall upper header.

Flue gas discharge from two ring headers arranged at rear wall upper, enter into

cyclone.

For wearing, spud which diameter is1025 welded at cone under furnace

bottom, water panel and its bottom, rear part of furnace roof and some area of furnace

outlet. The pitch between upper and down row spud is 30mm, angle staggers 15

degree; wearing layer thickness is around 60mm (water wall centerline). Butt-welding

bead at gas side of water wall tube above wearing layer shall be worn flat, welding

bead remnants height shall be not less than 1mm.

3.3. Back pass heating surface

Back pass heating surface includes high temperature superheater, enclosure

superheater, economizer, hanger tube and tubular air preheater. The back pass upper

part is divided into front and rear gas duct by division wall enclosure superheater.

Front gas duct has reheater insidewhile rear gas duct has high temperature

superheater and second grade economizer in sequence inside.

The cross-section of back-end convection ductwork is 12243.8width 6400.8

depth.The pipes used for front and rear enclosure wall are of 45 5 tube.

The enclosure division wall adopt 516 tube, with pitch equal for 114.3mm,

membrane wall type structure. Both front and rear enclosure wall has 107 tubes; both

left and right enclosure side wall have 57 tubes; enclosure division wall have 108


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tubes. The upper part of enclosure front wall has 2 annular headers, which connect to

cyclone separator flue gas duct outlet, and thus form the flue gas duct inlet. All the

headers at enclosure wall are 273 36.

High temperature superheater tube bundle adopts in-line arrangementthe two

ends of heating surface piping are rested upon enclosure division wall and enclosure

rear wall. The welding between supporting devices and enclosure tubes is to be

performed in the shop. The specification of high temperature superheater is 51

5.5mm tubes, double tubing loop tube coil bundles, with pipe transverse pitch for

114.3mmlongitudinal pitch for 102mmtransverse direction row number 106

portrait direction row number 72low temperature segment material SA213-T22

medium temperature segment material SA213-T22high temperature segment

material SA213 - T91. In order to ensure site welding are carried out to the same class

steel, a SA335-T91 tube with length of about 100mm is to be connected to the SA213

- T91 tube, which belongs to high temperature superheater outlet segment and is

outside the flue gas duct. The specification of high temperature superheater inlet

header is 324 55, material SA335-P12while outlet header specification is 324

40, material SA335-T91.The specification of the primary desuperheater header is

32428mmmaterial SA335-P12the secondary desuperheater Header specification

is 324 28, material SA335-P12.

All the reheater tube bundles are of in-line arrangementadopting superheater

hanger tube hanging mode.The reheater heating surface piping adopts 63.5 tubes,

twosome tubing loop tube coils, pipe transverse pitch for 114.3mm, longitudinal pitch

for 114mmtransverse direction row number 106, portrait direction row number 72

altogether 4 tube groupsand materials of them are SA210A1SA213-T12SA213-T2

and SA213-T91. In order to ensure site welding are carried out to the same class steel, a

SA335-P22 tube with length of about 100mm is to be connected to the SA213 - T91

tube, which belongs to reheater outlet section and is outside the flue gas duct. The

specification of reheater inlet header is 426 16, material SA-106B; The

specification of reheater outlet header is 45735, material SA335-P22

Feedwater is lead into primary economizer inlet header from one side of the


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boiler by 273 25 feed water pipes. The specification of the primary economizer

pipes is 51 5mmmaterial SA210A1with pipe transverse pitch for 90mm

transverse direction row number 70longitudinal pitch for 102mmportrait row

number 52arranged into 2 groups. And then feedwater is lead into second stage

economizer through a 273 25 connecting pipe. The specification of the

secondary economizer pipe is 515material SA210A1, pipe transverse pitch for

114.3mmtransverse direction row number 106longitudinal pitch for 102mm

portrait row number 48arranged into 2 groups. Finallyfeedwater leaving from the

second stage economizer is to be lead into the drum, through 2 219 20

connecting pipes and 12 108 10 branch pipes.

The air preheater is arranged in the back pass. Because the blast pressures of the

primary and secondary air are greatly differentthe channel boxe is divided into 2

independent air ductprimary air channel box is located at the right side of the boiler

while secondary air channel box is located at the left side of the boiler. Both of them

have 3 layers of channel boxes, with tube bundle of horizontal in-line arrangement.

The entire load of air preheater is laid upon a layer of boiler frame transverse beam.

Both Primary and Secondary air air preheater are three-pass, of in-line arrangement

transverse pitch for 75mmlongitudinal pitch for 75mmprimary air air preheater

transverse direction row number for 104secondary air air preheater transverse

direction row number for 72.

3.4 Cyclone separator and return device

See the 573-1-8609

3.5 Ash cooler

See the documents of provider

3.6. Boiler framework as well as platforms and stairways

Boiler framework is full-steel structure, a pair-column type, and the boiler roof

has light steel boiler house cover. The distance of boiler framework column from G to

K row is 37200mmwith main span width for 21000mmboth left and right sub-span

width for 5000mm, 5 layer of rigid platforms arranged in the vertical direction, the


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elevation of them are EL.9000EL.21200EL.33200EL.45200 and EL.52700,

ensuring the stability of the whole boiler framework. Besides bearing the load of

boiler proper, the boiler framework can also bear the loads of the Pipes for steam and

water, gas, air, coal, oil and limestone, and also loads of soot-blowing equipment,

light boiler house roof cover, anti-wear and heat insulating materials, as well as some

load brought by the elevator (including wind force, earthquake force).

Boiler framework is designed for operation at ZoneIS-1893Part 1area,

and the basic wind press 50m/smain components are connected by the friction-type

torsion shear type high-strength boltnormal components are connected by welding.

The design of the platform, footpath and staircase has enough strength and hardness.

The live load of the platform is 10kPa (excluding the platform deadweight); the live

load of the maintenance platform is 4kPa; the live load of the other platforms is

2.5kPa; the live load of the staircase is 2kPa. Boiler operation floor is designed at

elevation 9m, Adopting checkered steel platformdrum water control chamber

platform is laid with checkered stee; plate, and the other passage platform adopts

zincification grid plates.

3.7. Hangers and supports for pressure parts

Except the primary economizer is laid upon the support beam of boiler

structure , the other pressure parts are supported by the boiler roof steel frame through

hangers and supports. In order to decrease the bending press born by the hanger rod

root during boiler operation, each heating surface lifting point is to preset offset in

every expansion direction according to different expansion capacity.

Because the drum has great load and large vertical height, U type hanger rod is

used to install the drum. 2 hanger rods are arranged at both side of the drum. The

expansion capacity during drum hot-condition operation has been taken into

consideration to decide the distance between centers of installation location in cold

condition. The hanger rod upper end is laid upon the support beam of the drum by

screw nut. During installation, for the purpose of adjusting the drum's height,

hydraulic jacks are placed at both ends of the supporting beam. Waterwalls front wall

is hung upon the boiler roof steel structure by rigid hanger and lifting eye, which are


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welded to the pipe. While all the other 3 walls and waterall panel are hung upon the

boiler roof steel structure by rigid hanger on the header.

High coronet sealed supporting structure is used to hang the platen superheater.

This structure can be seen in 502573 - E1 01 furnace and down comer arrangement

drawing, as well as 502573 - E1 - 04 boiler roof lifting point and piping arrangement

drawing. The load of curtain panel are laid upon The middle transition beam through

small hanger rod, every 7 curtain panels' transition beams form the frame structure

altogether 4 transition beam frame structurethen they are hung to the boiler roof steel

structure by spring hangerensuring this hanger always on strained condition during

boiler hot-condition operation. One end of high temperature superheater tube group

and second stage economizer tube group is laid upon the enclosure rear wall, while

the other end is laid upon the division wall. The high temperature superheater

inlet/outlet header is laid upon the enclosure rear wallaround back pass enclosure

wall and division wall are hung to the boiler roof steel structure by rigid hanger.

Each row of pendant tube hang 2 reheater tube-row. Both pendant tube and

reheater tube-row are assembled by corrugated plate and tightening in the shop. The

load of the whole reheater tube group is hung to the boiler roof steel structure through

the rigid hanger and the lifting eye at upper part bend of the pendant tube. The

reheater inlet/outlet header is laid upon the enclosure front wall.

4. Others

4.1. Anti-wear measures

Because the boiler adopts circulating fluidized burning mode, plentiful circulation

materials are existed in the firing system. Furthermore, the material circulating ratio

attains 30. Therefore the anti-wear measures for firing system and tail heating surface

are of great importance.

To select furnace cross-sectional area per flue gas volume generated by firing,

and to control the flue gas velocity within the prescribed range of performance

standard, can greatly decrease the wearing at furnace heating surface. In the back pass

convection gas duct, Although the ash content in the gas is low, the rigidity of the gas


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increases as the gas temperature decrease, so to choose a suitable gas velocity is a

good way to wearing on convection surface.

Furnace air distributors are poured over by about 200mm thick antifriction

pouring material. The waterwall pipes at the furnace cone segment are welded by pin

bolt, and laid with 70mm thick distance to the center of the pipe high temperature

fireproof anti-wear layer. At the transition part between cone segment and vertical

segment, Waterwall pipe are bended towards outside the boiler, ensuring the falling

material within the furnace can fall over the anti-wear layer. In addition, The weld

seam of the gas side pipes above the anti-wear layer shall be grinded smooth, and the

residual height of weld seam shall be no more than 1mm.

For both platen superheater and waterwall panel at the upper furnacethe pipes at

the lower part surface and wall-penetrating area are welded by the pin bolt, and laid

with 70 mm thick (distance to the centerline of the pipe) high temperature fireproof

anti-wear layer to prevent pipe form wearing by the ascending gas.

At furnace upper rear wall gas outlet, 70mm thick, 1000mm wide annular high

temperature fireproof anti-wear layer are laid upon the waterwall pipe surface, to

prevent the wearing to these pipes as changing gas flow.

The inner wall of cyclone separator inlet gas duct,cyclone separator and cyclone

separator outlet gas duct adopts anti-wear castable material, and is fixed by high

density pin bolt, guaranting anti-wear material firm and reliable. When laying the

114mm thick high temperature anti-wear layerthe surface of the anti-wear layer shall

be flat, and transition shall be smooth. The center pot of the separator adopts high

temperature high strength anti-wear austenitic stainless steel.

Within the U type material return leg, FBAC and its connecting pipeline, all the

internal surfaces of gas duct, which contact with high temperature high concentration

ash particles, shall be laid with a layer of high temperature anti-wear pouring material

and a layer of fireproof insulation pouring material, and fixed by Y type pin bolt.

For the heating surface of tail convection gas duct such as high temperature

superheater, reheater, economizer and air preheater, anti-wear cover shall be added to

the first row of pipe windward at flue gas inlet, to prevent pipe from abrading.


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Both the ingredient and performance index of the anti-wear refractory material

shall meet the requirements raised by Shanghai Boiler Works, Ltd, details refer to

.

4.2. Sealing

CFB's furnace pressure is barotropic during operationand the operation pressure

at the lower furnace dense-phase region can reach about 10kPa. Through excellent

sealing design, SBWL can prevent gas leakage and ash leakage, and therefore provide

a clean and easeful work environment for the boiler user.

The boiler has 3 expansion centers, namely, in furnace, in cyclone separator and

in back pass. Among them, 3 layers of expansion center are designed on boiler

waterwall (elevation for EL.16700, EL.32500 and EL.41500), a layers of expansion

center is designedon on cyclone separator EL.33200, 3 layers of expansion center is

designed on back pass enclosure wall (elevation for EL.33800, EL.40800 and EL.

47200 ). This design can boiler heating parts can freely expand in order in a certian

direction during operation. Every sealing structure has determinate expansion

direction and capacity, which can provide definite reference value and reliable basis

for the sealing design.

The furnace adopts the membrane wall structure, which is formed by welding

bare tube and flat iron together. This membrane wall structure have good airtightness,

and can be laid with light refractory furnace wall to decrease boiler deadweight.

Boiler roof pipes are formed by the bending of front wall waterwall, so their

expansion is the same as of the about waterwall. This enable boiler roof sealing

design to be simplethe boiler roof pipe can be seal welded with the 2 sides

waterwalls. Upper furnace has wide pitch waterwall and platen superheater, whose

Transverse pitch are larger than 600mm. Therefore this is easy for site welding and

can guarantee the installation quality. Waterwall panel and boiler roof pipe directly

adopt comb type steel plate welding, And the platen superheater adopts metal

expansion joint for sealing, which can absorb the expansion difference between platen

superheater and waterwall. At the lower header tube seat of waterwall, sealing box is

used for sealing, while At the tube seat of annular header, flanged plate is used for


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sealing. Waterwall has Positive pressure manhole door . The inner surface of manhole

door is laid with refractory material and thermal insulating material, which can

effectively prevent flue gas leakage raised by heating distortion.

At the connecting points between furnace and cyclone separator inlet gas duct,

between cyclone separator and inlet gas duct, between cyclone separator and outlet

gas duct, between cyclone separator and material return device, between cyclone

separator outlet gas duct and back pass, and between back pass and air preheater inlet,

metal/non-metal expansion joints are placed to absorb heat displacement. The

expansion joint itself is anti-wear and high temperature resistant. Compression

amount of the expansion joint shall reserve suitable allowance, in order to guarantee

certain service life.

The around enclosure wall of back pass adopts the membrane type wall structure,

which are formed by welding between bare tube and flat iron. Because all the

enclosure walls are steam cooling type, all the expansion values are the same, so the

sealing design can be simplified. The connecting points between back pass boiler roof

pipe and enclosure front wall/rear wall has no header, but pipes for direct connection.

This guarantees the sealing in structure. Boiler roof pipe are directly welded to the

enclosure sidewall, without any expansion joint. The tube seats of enclosure front

wall annular header adopts flanged plate for sealing. Sealing box is used at high

temperature superheater inlet/outlet, reheater inlet/outlet, and pipe penetrating area

between enclosure front wall and enclosure rear wall. The sealing box has metal

expansion joints at its upper and lower parts, which can absorb the heat displacement

in width direction.

boiler mannual

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