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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
2
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
14
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.
16
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.
6
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.
22
COGENERATION BATTERY COGENERATION BATTERY COMBINED STEAM & POWER GENERATION RECORDCOMBINED STEAM & POWER GENERATION RECORD
23
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
24
--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.
28
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