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ADVANCES IN HIGH PRESSURE COGENERATION ADVANCES IN HIGH PRESSURE COGENERATION BATTERY IN SESHASAYEE PAPER PLANTBATTERY IN SESHASAYEE PAPER PLANT

T. G. T. G. SundaraSundara Raman &Raman &R. R. ThirumuruganThirumurugan

SeshasayeeSeshasayee Paper and Boards LimitedPaper and Boards Limited

99thth ENERGY EFFICIENCY SUMMIT 2010 ENERGY EFFICIENCY SUMMIT 2010 EnCon in Thermal SystemsEnCon in Thermal Systems

CIICII

ChennaiChennai4 Sep. 20104 Sep. 2010 1

COMPANY PROFILE• Established in the year 1961• Started with a production of 20,000 tonnes of paper/year• SPB produces now ~1,20,000 tonnes of paper/ year• 2 High Pressure Cogeneration Plants with state of the

art technology • Present Gross turnover is about Rs 5000 million • An ISO-9001 / ISO-14001 / OHSAS organisation• Two projects are under DVR Stage for CDM/VCS

CHOICE OF HIGH PRESSURE STEAMCHOICE OF HIGH PRESSURE STEAM

• Low Specific Steam Consumption - SSC (in other words, more power generation per unit ton of steam)

• Flexibility to produce more steam or more power

• High cycle efficiency

7.1

5.44.6

4.2 3.8 3.5

012345678

SSC

(Te/

Mw

h)

21 32 44 63 87 105Steam Pressure (bar)

Impact of Steam Pressure on SSCHigh pressure Steam (105 bar)High pressure Steam (105 bar)

MERITS OF HIGH PRESSURE COGENERATION

Low cost of total energy generation & conversion

Reduced dependence on grid power

Flexibility in operation depending on steam & power needs during all time of the year

Quality steam at desired levels for process requirement

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H.P. COGENERATIONH.P. COGENERATION

•• Pulp & Paper IndustriesPulp & Paper Industries

•• Sugar PlantsSugar Plants

•• Petrochemical IndustriesPetrochemical Industries

•• Fertilizer UnitsFertilizer Units

•• Chemical IndustriesChemical Industries

SPECIFICATIONS OF THE 2 HP COGEN UNITS

CPP Chemical Recovery Cogen

Boiler #10 ParameterParameter Boiler #11

AFBC Boiler TypeType Chemical Recovery Boiler

117 TPH Rated Steam EvaporationRated Steam Evaporation 83TPH(Phase1) I140TPH(Phase2)

106 kg/cm² SOPSOP 65 kg/cm²

510•C SOTSOT 465•C

135•C Feed inlet temperatureFeed inlet temperature 135•C

Imported coal FuelFuel Black liquor@ 70% solids concn.

21 MW- DEC STGSTG 16 MW- EBP

10.5/4.0 kg/cm² E1/E2E1/E2 10.5/4.5 kg/cm²

0.09 ata CondensingCondensing --

20.4 MW CapacityCapacity 10MW(Phase1) / 16 MW(Phase2)6

POST MDP – [PHASE – I] – FLOW CHART

0.1 at a

22 tph42 tph

Falling Film Evapo rato r

8 MW

EBP16MW STG

EBP16MW STG

70 tph

95 tph

DEC21MW STG

DEC21MW STG

17.5 MW

0.5 MW

Weak Black Liquor from Pulp Mill

Strong Black Liquor 70%

Concen tration

Total Power : 26 MW

New CRB65 kg/cm 2

CW

64 tph6.5 tph

586 tpd

AFBC#10106 kg/cm2

CPP

GRID

IMPORT

11 kg/cm 2

Steam Header

To ProcessStation Consu mption

4 kg/cm2

Steam Header

To ProcessStation Consu mption

3

117 TPH AFBC High Pressure BOILER

• Atmospheric Bubbling Fluidised Bed Combustion Boiler with economizer & flue gas air heater

• High pressure (106 bar) steam unit

• 117 TPH Steam Generation

• 510ºC Steam Temperature

• Enviro Coal as Fuel

• High Bed Temperature :950- 970°C

• 135ºC Feed water Temperature

• Highest Efficiency (~ 84% on GCV)

• 3 Field ESP ( SPM <20 mg/Nm3)

• Lower N2O (GHG) for a FBC unit

Efficient Turbo Efficient Turbo ––Generators Generators BHEL STEAM TURBINESBHEL STEAM TURBINES

0.06 MW0.07 MWGain

98.1 %97.9 %Actual

97.7 %97.6 %Design

Extraction Back Pressure

Double Extraction CondensingType

16 MW21 MW

CPP- COGEN LADDER CHART

STGin

LP C EXH

STGSTG ~G~G

MP

BOILER 10BOILER 10

FUEL (COAL)92 MW

76

73 MW15 MW15 MW

MP

2118½1

LPC

POWER

.

4

CPP CPP ––II [Recovery]II [Recovery] COGEN LADDER CHARTCOGEN LADDER CHART

108MWt

65½

658 MW

50 5

Black Liquor Solids

Boiler 11

MSH

MPLPLP MP

ENERGY DISTRIBUTION ACROSS 16 MW STG

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Turbine Extraction-Exhaust Steam Range

ZONE 21 MW STG 16 MW STG

E1 [ MP] 0-30 TPH 0-60 TPH

E2 [LP] 0-60 TPH 30-130 TPH

Condensing 25-50 TPH X15

POWER ENHANCEMENT SCHEME-First of its kind

• With reduction in E1 steam extraction flows ( as related to

design flow ), the temperature at turbine nozzle increases relating to lower Electrical Power conversion and higher

de-superheating

• Hence Splitting E 1 ( M.P. steam extraction ) flows between

the 2 steam turbines to be minimized to the extent practicable.

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5

E1 Nozzle Steam E1 Nozzle Steam vsvs Saturation TemperaturesSaturation Temperatures. E1 [MP Steam]E1 [MP Steam]-- Energy in Steam to DSHEnergy in Steam to DSH

0

0.5

1

1.5

2

2.5

- 16TPH

25TPH

40TPH

Low Load,MWHigh Load,MW

E2 Nozzle Steam E2 Nozzle Steam vsvs Saturation TemperatureSaturation Temperature

.

. E2 [E2 [LPSteamLPSteam]]--Energy in Steam to DSHEnergy in Steam to DSH

0

0.2

0.4

0.6

0.8

1

1.2

48TPH 72TPH 130TPH

Low Load MWtHigh Load MWt.

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POWER ENHANCEMENT SCHEMEPOWER ENHANCEMENT SCHEMECONCEPTCONCEPT

• Splitting E 1 ( M.P. steam extraction) flows between the 2 steam turbines to be minimized.

• Objective is to ensure entire E 1 flow through one of the

2 STGs

• Accordingly split E2 (L.P. steam extraction) flow between

the 2 steam turbines

• In case of E2 , there is hardly any impact ; hence the above

philosophy of splitting is not taken up.21

POWER ENHANCEMENT SCHEMEPOWER ENHANCEMENT SCHEME[PES][PES]

• E 1 ( M.P. steam extraction) flow had been reduced in

16 MW steam turbine from 21 TPH to 6 TPH as of now ; this flow had been added in E1 of 21 MW steam turbine.

• Accordingly E2 (L.P. steam extraction) flow is being

adjusted between the 2 steam turbines.

• Thus the overall MP and LP steam flow rates are left

undisturbed.

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COGENERATION BATTERY COGENERATION BATTERY COMBINED STEAM & POWER GENERATION RECORDCOMBINED STEAM & POWER GENERATION RECORD

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6.666.661716017160114296114296Aug Aug

6.706.701690616906113218113218JulyJuly

6.696.691695016950113660113660MayMay

6.836.831604516045109800109800AprApr

Spec. Steam Consn. Te/MW

Power Gen.MU

H.P.SteamTe

20102010

POWER ENHANCEMENTPOWER ENHANCEMENTOPERATIONAL COMPARISONOPERATIONAL COMPARISON

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--30304584586.666.66AugAug**[1[1--28]28]

--20203293296.706.70JulyJuly

--19193093096.696.69MayMay

BaseBaseBaseBase6.836.83AprApr

E1E1--equiv.equiv.TPDTPD

Power equiv.Power equiv.‘‘000 units000 units

Spec. Steam Consn. Te/MW

20102010

7

GHG Reduction through PESGHG Reduction through PES

390390458458AugAug

280280329329JulyJuly

263263309309MayMay

BaseBaseBaseBaseAprApr

CO2 [equiv.]CO2 [equiv.]Te Te

Power equiv.Power equiv.‘‘000 units000 units20102010

POWER ENHANCEMENT & GHG REDUCTIONPOWER ENHANCEMENT & GHG REDUCTION{ Base{ Base--line : April 2010 }line : April 2010 }

-500

50100150200250300350400450500

April May July August

Power'000 unitsCO2 eq. TE1 TPD

Advanced Steam Pipe InsulationAdvanced Steam Pipe Insulation[5[5ººC reduction]C reduction]

0

0.05

0.1

0.15

0.2

0.25

0.3

60TPH

80TPH

100TPH

120TPH

Energy MWt

RECOMMENDATIONS & CONCLUSIONS

• Maximize combined cycle efficiency in electrical power with either of the turbines acting as slave using Power enhancement scheme [PES].

• Main steam temperature drop from Boiler to turbine to be minimal ( through quality and adequate insulation) say 5 to 6°C.

• The resultant saving in heat in HP steam shall be gainfully converted to Power at no extra fuel input.

• With PES in place, GHG reduction would be of the order of 5000 Te CO2 equiv.

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