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Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Blending of Imported Coal Blending of Imported Coal with Indian Coals &with Indian Coals &
Its Associated Effects on Its Associated Effects on Boiler Design and OperationBoiler Design and Operation
Dr V T Sathyanathan General Manager / Quality
B H E L, Trichy 620014
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Dr V.T.Dr V.T.Sathyanathan Sathyanathan Born in 1948 in Pondicherry StateGraduated from Coimbatore Institute Of Technology,Coimbatore, Tamilnadu, India under Madras University, India with First Class Degree in Mechanical Engineering in 1971. Masters Degree with Distinction in “Design and Production of Thermal Power Equipment” from Regional Engineering College under BharathidsanUniversity Trichy Tamilnadu, India in 1984.Ph.D from Regional Engineering College underBharathidsan University Tiruchy, Tamilnadu India in 1998. Ph.D thesis was on “Prediction of Unburnt Carbon in Tangentially Fired Boiler Using Indian Coals”.
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Dr V.T.Dr V.T.SathyanathanSathyanathanJoined BHEL in 1973 in the R&D Department, in 1974 moved to Field Engineering Services & worked in various capacities till 2000Worked as Additional General Manager / R&D for two years –Jul 2000 to Jul 2002Was heading as Additional General Manager / FES & SAS for two years – Jul 2002 to Jul 2005 Head whole Engineering Department as the Additional General Manager /Engineering (FB) -Jul 2005 - Aug 2006Presently working as General Manager / Presently working as General Manager / QualityQuality..
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Dr V.T.Dr V.T.SathyanathanSathyanathanSpecialized in combustion, boiler performance optimization, boiler testing and troubleshootingHas wide experience in the following areas:
Trouble shooting boiler problems in the areas of high pressure valves and boiler systemsTrouble shooting of all combustion problems in high pressure boilersPerformance optimization of high pressure boilersPerformance testing of all boilersTrouble shooting of Chemical Recovery boilers in paper plantsPerformance optimization of Chemical Recovery boilersBoiler Life Assessment StudiesPlant Performance Improvement studies in old boilersCoal petrography studies to understand combustion problems in coal fired boilers
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Dr V.T.Dr V.T.SathyanathanSathyanathanWas appointed as the enquiry committee member by Government of Tamilnadu, for investigation of a severe explosion in the Rotary Holding Furnace (RHF) in Copper Smelting Plant of M/s. Sterlite Industries (I) Ltd., Tuticorin TamilnaduHas presented more than 35 papers in both National and International Seminars & Journals.Member of ASME, USA Vice – Chairman IIM Trichy Chapter. Life Member Indian Institute of Engineers. Member IIWChairman ISNT Trichy ChapterHas guided more than 15 projects for both UG & PG students of EngineeringTeach M.E Design & Production of Thermal Power Equipment Students of REC Trichy Teach Special Subjects In Horticulture to M.Sc / B.Sc students -Art Of Bonsai & Cacti
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
ArrangementArrangementBlending of coalEstablishment of ProcedureGrouping of Indian Coals for Boiler DesignEffect Of Coal Quality On Boiler PerformanceEvaluations carried outConclusions
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Blending of coalBlending of coal
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Blending of coalBlending of coal
Burnsgivingheat
Organics
Behaviourfriendly
not friendly
Inorganics
Transportdrying
Moisture
Coal
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Sudden or low change in furnace behavior leading to low boiler efficiency, load reduction and serious outageTime to turn around is normally highCan also lead to irrecoverable change in furnace behaviour
Why Fear Blending of coalWhy Fear Blending of coal
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Decision about coal blending must deal with
uncertainty and variability in coal propertiesthe effect of off-design coal characteristics on power plant performance and cost.
Blending of coalBlending of coal
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Blending of coalBlending of coal
Can pose peroblem
High Moist High VM Low FC
low rank
Low Moist Low VM High FC
High rank
Organics
Composition Trasformation Deposition Transport Aglomeration Trace Elements
In-organics
Blending
Drift In-situ
Type of Formation
Lignite Bituminus Anthersite
Rank of Coal
Blending of Coals
Time of residence
High swirl Low Swirl
PC FBC
Combustion
Temerature Size
Reducing Oxidising
Oxygen
Effected by
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Can pose problem
Organics In-organics
Blending
Drift In-situ
Type of Formation
Lignite Bituminus Anthersite
Rank of Coal
Blending of Coals.
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Blending of coalBlending of coal
High Moist High VM Low FC
low rank
Low Moist Low VM High FC
High rank
Organics In-organics
Blending
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Blending of coalBlending of coal
Organics
Composition Trasformation Deposition Transport Aglomeration Trace Elements
In-organics
Blending
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Blending of coalBlending of coal
Time of residence
High swirl Low Swirl
PC FBC
Combustion
Temperature
Furnace Particle
Size
Reducing Oxidising
Oxygen
Effected by
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Establishment of ProcedureEstablishment of ProcedureFor Blended Coal Firing
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Need For Blended Coal FiringNeed For Blended Coal Firing
Indian coals contain high ashPreferable to limit ash content of coals fired at TPS to 34%Price of low ash imported coal with higher HHV is equivalent to that of Indian coalsAvailability of new fuels like petcoke, refinery residue, etc at a comparatively lower price
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Procedure Developed Procedure Developed
Laboratory analyses of fuel samplesTrials at Fuel Evaluation Test Facility at various blend proportions and optimising the blend proportionImplementation of the recommended blend proportion at TPS for long duration observationFurnace inspection during shut down after long duration operation
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Basis for recommendationBasis for recommendationFlame stabilityCarbon lossHeat flux reduction due to slagging and foulingHeat flux regain ability on wall blowingSH and RH spray levelsEmissionAcid dew pointAsh resitivity
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Coal Boiler FurnaceDesign
BoilerOperation
Slagging
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
ElivationHeat Loading
Vol HeatLoading
Size
Slop AngleAvoid Ash Load
Shape
Furnace
High Swirl Low Swirl
Burner
Water Steam
Type Nos
Soot Blower MillSizing
Air / CoalRatio
Primary
WindboxControl
Secondary
AirDistribution
ID FanSizing
Slagging
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Calcite Pyrites Ouartz
Oxidizing Reducing
700 .C S1H2SFeS.Fe2 (SO4)3 FeO Fe TemperatureFeo (Partial Melt) invesions(Partial melt) 950 .C
970.C S1H2S1000.TO 1100.C
CO2
Fe
Cao liquid Fe2 O3 SiO2
2570.C liquid liquid1600 .C 1723 .C
Phase Transforamation Of Some Mineral Matter Commonly Found In Coal
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Kaolinite Illite
Metakaolinite (A12 O3 2sio2
950 .C925 .C SI O2
(Clay lattica destroyed) Spinal amorphous quartzA12 O3 Mgo glass Si O2
Silion Spinel 1050.C(2A12 O3.3 Si O2
1100 .C Si O2
1100.C
Mullite1:1Mullite type phase 1300.C (3A12 O3
(A12 O3.Si O2) 2Si O2
1400 C Sio2(Coristobailite) 1400.C
Mullite3A12 O3 . 2Si O2 liquid glass
May not be completelyliquid untill 1800 .C
Phase Transforamation Of Some Mineral Matter Commonly Found In Coal
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
MAJORSILICATES -[ CLAY MINE RALS KAOLINIT E Al2 Si 2 O5 (OH) 4
ILLITE - CLAY MINERALQUARTZ Si O2
MINORCALCITE Ca CO3
CARBONATE DOLOMITE (Ca, Mg) ( (CO3) 2ANKERITE CA (FE, Mg) CO3
SIDERITE FECO3
DISULFIDES PYRITE Fe S2 CUBICMARCASITE Fe S2 ORTHORHOMBIC
COFUIMBITE Fe2 (SO4)3 9H2 OSZOMOLONOKILE Fe SO4 2H2 O
SULFATES GYPSUM Ca SO4 2H2 OBASSANITE Ca SO4 1/2 H2OANHYDRITE Ca SO4
JAROSITE K Fe3 (SO4) 2 (OH)6
FELDSPARE PLAGIOCLASE (NaCa) Al (Alsi) Si2O8
ORTHOCLASE KALSi3 O8
Common Coal Minerals
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
1 LB COAL1.7 SLON
1.7F 1.75
1.7 FLOAT 1.7 SINK1.5 SOLN 1.9 SLON
1.55 1.9F 1.951.55x1.7F 1.75 x 1.9FPRACTION PRACTION
1.5F
1.5 FLOAT 1.9 SINK1.3 SLON 2.1 SLON
2.1F
1.35 .95 x 2.7F 2.15FRACTION
1.35 x 1.5F 2.1 SINKFRACTION 2.5 SOLN
1.3F2.5F
2.551.3 F 2.15x2.9FFRACTION FRACTION
2.5 SINK2.95
2.55x2.9FFRACTION 2.95
2.95FRACTION
Gravity Separation Procedure
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
EXPERIENCE SEVERE SEVERE MODERATE NONE NONE
CYCLONE INDEX MED - HIGH LOW-MED. LOW LOW LOW
SULFUR SLAGGING INDEX HIGH MEDIUM LOW LOW LOW
FUSION SLAGGING INDEX SEVERE SEVERE MEDIUM LOW LOW
VISCOSITY SLAGGING INDEX MED - HIGH LOW - MED LOW LOW LOW
Slagging Index Matrix
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
SlaggingSlagging/deposition indices/deposition indicesAsh deformation temperaturesLower the number, higher the tendency for depositionBase/ Acid RatioIn certain ranges the combinations have low melting temperatures, resulting in higher depositionIron/ Calcium ratiolower fusiblity temperatures in certain rangesIron Content in AshHigher the content , more the propensity for depositionSilica / Alumina RatioLower fusiblity temperatures at higher ratiosViscosity Index
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Grouping of Indian Coals Grouping of Indian Coals for Boiler Designfor Boiler Design
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
44 major coal fields in peninsular India - 450 seams
Raniganj, Talcher, Ib-Valley, Jharia, N.Karanpura, Korba, Godavari, Singareni, Rajmahal, Karanpura, Singarauli, Wardha and Bokaro, account for 90% of the reserves.
Most of the coal resources are concentrated within 78 to 88 E longitude and 22 to 24 N latitude
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Distribution of Fuel RatioDistribution of Fuel Ratio
0
10
20
30
40
50
60
70
80
0.0-0.2 0.2-0.4 0.4-0.6 0.6-0.8 0.8-1.0 1.0-1.2 1.2-1.4 1.4-1.6 1.6-1.8 1.8-2.0 2.0-2.2 2.2-2.4 2.4-2.6 2.6-2.8Range of Fuel Ratio
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Distribution of AshDistribution of AshPer MillionPer Million KcalsKcals
010203040506070
20-40 40-60 60-80 80-100
100-120
120-140
140-160
160-180
180-200
Ash Range (Kgs)
Num
ber o
f Coa
ls
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Distribution of Initial Distribution of Initial Deformation TemperatureDeformation Temperature
020406080
1000
-1020
1020
-1040
1040
-1060
1060
-1080
1080
-1100
1100
-1120
1120
-1140
1140
-1160
1160
-1180
1180
-1200
1200
-1220
1220
-1240
1240
-1260
1260
-1280
1280
-1300
IDT Range (Deg.C)
Num
ber o
f Coa
ls
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
FIXED CARBON / VOLATILE MATTER - DISTRIBUTION ( Group 1 - 0.6 to 1.2 ; Group 2 - 1.2 to 1.8 ; Group 3 - 1.8 to 3.01)
101
144
33
0
20
40
60
80
100
120
140
160
1 2 3Coal Group
No.
of C
oals
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
ASH LOADING - DISTRIBUTION( Group 1 - 20 to 90 Kg/MKcal; Group 2 - 90 to 140 Kg/MKcal;Group 3 -140 to 200 Kg/MKcal)
88
148
42
0
20
40
60
80
100
120
140
160
1 2 3
Coal Group
No.
of C
oals
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
INITIAL DEFORMATION TEMPERATURE - DISTRIBUTION( Group 1 -1000 to 1100 Deg C; Group 2 - 1100 to 1200 Deg C;
Group 3 - 1200 to 1290 Deg C)
24
161
93
0
20
40
60
80
100
120
140
160
180
1 2 3
Coal Group
No.
of C
oals
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
COAL GROUPING CONSIDERING ALL THE 3 ASPECTS
30
223
16
0
50
100
150
200
250
1 2 3
Coal Group
No.
of C
oals
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Effect Of Coal Quality On
Boiler Performance
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Coals vary widely in their properties
mine to mine and seam to seamCoal firing therefore presents a varying set of demands before the boiler designer
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Boiler designBoiler designCoal Properties influence
The sizing of the boiler heat transfer surfacesThe flue gas velocitiesThe size of boiler auxiliaries
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Effect Of Fuel On Boiler DesignWide range of coal properties
Lead to oversized pulverising/firing equipment• Limitation on turn down • Auxiliary power consumption will go up.
Oversized furnace• Attaining rated SH, RH outlet temperature becomes
difficult.Oversizing pulverisers and airheaters to handle occasionally high moisture coals
when handling normal moisture coals• there will be excessive tempering air• higher gas outlet temperature
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Heat Transfer in Furnace Heat Transfer in Furnace -- UncertaintiesUncertaintiesFurnace wall condition
The deposition potential prediction by use of slagging indices still subjective
Laboratory determination of emissitivity & absorptivity does not reflect the furnace conditions.Heat release rates
FC/VM ratio only indicative ; coal petrography may indicate different results
Particle finenessHigher fineness at times can separate the slow reactive particles from the high reactive, resulting in delayed
combustion.Accuracy of Prediction by theoretical methods affected by complexity of factors
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Designing for erosion protectionDesigning for erosion protectionIndian coals contain large quantum of ashThe quantity of ash passing thru the boiler is of the order of 125 kg/ Million kcal (compared to 40 kg/Mkcal for an average grade coal)
Indian coal-ash highly erosive- 60% Silica.Flue gas velocity in the range of 10-12 m/s adoptedAdditional thickness provided on tubes in erosion prone areasSacrificial shields/ baffles provided on leading tubes/ bends
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Design of heat transfer surfacesDesign of heat transfer surfaces
Furnace design is the most crucial part of boiler design
Coal characteristics decide the heat release rates, furnace wall conditions and consequently the the furnace heat transfer
Proper understanding of the coal behaviour w.r.t combustion and heat transfer very essential in designing for satisfactory boiler performance
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Furnace Heat TransferFurnace Heat TransferFurnace wall condition
Combustion Heat release rateEmissivity, absorptivity and thermal conductivity of deposits.
Ash dust loading
Pulverised fuel finenessMill Combination (Top, Middle, Bottom)Air regime for combustion
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Evaluations carried outEvaluations carried out
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Evaluations carried outEvaluations carried outBlended firing of Petcoke (Reliance) and coal for GEB, Sikka TPSBlended firing of Indian coals with Indonesian coal at Raichur TPS for KPCLCo-firing imported coal with oil for TATA Power, TrombayCo-firing ground nut shell with bagasse for EID parry, NellikuppamREL Dahanu 250 MW – 30% Indonesian Coal + 70% Indigenous washed coal
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Evaluations carried out Evaluations carried out –– ContCont
GSECL Gandhinagar unit 1 & 2 120 MW –20% imported coal in one exclusive mill elevationGNVFC Bharuch 200 t/hr – 50% imported coal – Australian, Chinese,South AfricanMahagenco Chandrapur 500MW unitsTNEB Mettur 210MW – Indonesian & AustralianTNEB Tuticorin 210MW – Indonesian & Australian
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
ConclusionsConclusions
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
ConclusionsConclusionsBlending of coals expected to grow over the next decade as electric utilities attempt to
Reduce costMeet SO2 emission limitsImprove combustion performance of their coals
All aspects of a blend’s behaviour & its effect on all components of the power stations, from the stock pile to the stack, should be considered before the most appropriate blend composition is chosen
IEA Publication
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Conclusions Conclusions (cont.)(cont.)
At present, the effect of coal blending on power station performance are not completely understoodEven if the blended coal closely resembles the design coal for the boiler, the blend does not perform the sameA limitation to blending coals is the compatibility of the coals themselves; problems are more likely when blending petrographically different coals or coals with different ash chemistry
IEA Publication
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Conclusions Conclusions (cont.)(cont.)
The impact of blending coals of different hardness on the finalize distribution & compositional distribution of the pulersied coal is sill not understoodNon-additivity properties make blend evaluation for power generation inherently complexTraditional indices for ash deposition are unreliable when applied to blends
IEA Publication
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Conclusions Conclusions (cont.)(cont.)
More work is required on understanding how the inorganic components of coals in the blend interact & how it affects ash behaviour, including its emisivity, reflectivity & thermal conductivitySO2 can be predicted with reasonable accuracyNo adequate means of predicting Nox
IEA Publication
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Conclusions Conclusions (cont.)(cont.)
Because of the complexity of the combustion process and the number of variables involved (which are still not fully understood), it is difficult to extrapolate small - scale results to full - scale plant. Thus, power station operational experience in a wide range of plant configurations with a variety of coal feedstock is essential for determining the practical significance of results from bench - and pilot -scale tests. More published data on how the behaviour of the coals / blends utilise in these tests differ from their actual performance in power station boilers are required.
IEA Publication
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Conclusions Conclusions (cont.)(cont.)
Tests are widely utilised, providing a preliminary indication of the behaviour of the coal / blend. One of the most successful outcomes of blending is in providing a fuel of consistent quality.Coal is a heterogeneous material and its properties and composition vary even within a single seam or single shipment / train load. There is a need to minimise the variability. This can be achieved by blending. Indian power stations use mainly blended coals only.
IEA Publication
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Prime ConcernPrime ConcernBoiler furnace Slagging
Lead to outages in many casesLead to load reductionPerformance parameters change
Arriving at the right proportion Maintaining the right mix
My conclusion
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
How power stations to viewLook at proximate and ash analysisLook for FC/VM ratio – idea on reactivityAsh composition ratios – slagging
Trial with low mixture ratio – 95% + 5%95% of regular usage coalWatch parameters like SH spray, steam temp, exit gas temp, unburnt carbon,load on bottom ash collection after maintaining load, steam pressure, excess air& mixture ratio for about a week
Blending of coalBlending of coalMy conclusion
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
ANY QUESTIONS PLEASEANY QUESTIONS PLEASE
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Thank You AllThank You All
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COALS IN UNIT 3 BOILER OF RAICHUR TPS DURING FEB 2001FIG: COMPARISION OF THE TREND OF SUPER HETER SPARY.
05
1015
2025
3035
40
0 100 200 300 400 500
TIME IN MINUTES FROM THE START OF TEST
TON
S / H
OU
R
sh spary TEST 1 100% SASTIsh spary TEST 4 78% SASTI+ 22% INDOsh spary TEST 7 70% SASTI & PRP+30% INDO
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COALS IN UNIT 3 BOILER OF RAICHUR TPS DURING FEB 2001FIG: COMPARISION OF THE TREND OF SUPER HETER SPARY.
0
5
10
15
20
25
30
35
40
0 50 100 150 200 250 300 350 400 450 500
TIME IN MINUTES FROM THE START OF TEST
TON
S / H
OU
R
sh spary TEST 1 100% SASTI sh spary TEST 15 100% MAHANADHI
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COALS IN UNIT 3 BOILER OF RAICHUR TPS DURING FEB 2001FIG: COMPARISION OF THE TREND OF SUPER HETER SPARY.
0
5
10
15
20
25
30
0 100 200 300 400 500
TIME IN MINUTES FROM THE START OF TEST
TON
S / H
OU
R
sh spary TEST 4 78% SASTI+ 22% INDO
sh spary TEST 14 80% MAHANADHI +20% INDO
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COALS IN UNIT 3 BOILER OF RAICHUR TPS DURING FEB 2001FIG: COMPARISION OF THE TREND OF SUPER HETER SPARY.
0
5
10
15
20
25
30
0 100 200 300 400 500
TIME IN MINUTES FROM THE START OF TEST
TON
S / H
OU
R
sh spary TEST 7 70% SASTI & PRP+30% INDO
sh spary TEST 12 70%YELLANDU+ 30%INDO
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COAL IN UNIT 3 BOILER OF RAICHUR TPS
COMPARISON OF FURNACE TEMPERATURE PROFILE
11000
20000
29000
38000
47000
1000 1200 1400 1600 1800
FURNACE TEMPERATURE (DEG.C)
FUR
NAC
E EL
EVAT
ION
(MM
)
100% SASTI COAL 78% SASTI + 22% INDONESIAN COAL70% SASTI + 30% INDONESIAN COAL
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COAL IN UNIT 3 BOILER OF RAICHUR TPS
COMPARISON OF INCIDENTAL RADIATION HEAT FLUX PROFILE
11000
20000
29000
38000
47000
50 100 150 200 250 300 350 400
INCIDENTAL RADIATION HEAT FLUX (KW/SQ.M)
FUR
NAC
E EL
EVAT
ION
(MM
)
100% SASTI COAL78% SASTI + 22% INDONESIAN COAL70% SASTI + 30% INDONESIAN COAL
Bharat Heavy Electricals Limited TIRUCHIRAPALLI
Committed to making a better world Dr V T Sathyanathan
BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COAL IN UNIT 3 BOILER OF RAICHUR TPS
COMPARISON OF FURNACE TEMPERATURE PROFILE
11000
20000
29000
38000
47000
1000 1100 1200 1300 1400 1500 1600 1700 1800
FURNACE TEMPERATURE (DEG.C)
FUR
NAC
E EL
EVAT
ION
(MM
)
100% MAHANADHI COAL 80% MAHANADHI + 20% INDONESIAN COAL
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BLENDED FIRING OF INDONESIAN COAL WITH INDIAN COAL IN UNIT 3 BOILER OF RAICHUR TPS
COMPARISON OF INCIDENTAL RADIATION HEAT FLUX PROFILE
11000
20000
29000
38000
47000
50 100 150 200 250 300 350 400
INCIDENTAL RADIATION HEAT FLUX (KW/SQ.M)
FUR
NAC
E EL
EVAT
ION
(MM
)
100% MAHANADHI COAL 80% MAHANADHI + 20% INDONESIAN COAL
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Typical Coal YardTypical Coal Yard
Coal Stockpile
Wetlands
Rail CarUnloader
Rail Line
Material Handling System Crusher House
Main Conveyor
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Literature example of the differences in actual HGI Literature example of the differences in actual HGI and calculated HGI for coal blendsand calculated HGI for coal blends
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NOxNOx--results for individual coals and results for individual coals and blendsblends
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Normally specified Coal Properties
Proximate Analysis
Ultimate Analysis
Calorific Value
Ash Constituents
Ash Fusion Temperatures
Hard Grove Index
YGP Index
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Moisture and ash free
C (%) O + N (%) H (%)
Wood 50 44 6
Peat 55-64 39-35 5-7
Brown Coal 60-75 34-17 4-8
Bituminous Coal 78-90 19-4 4-6
Anthracite 94-98 3-1 1-3
Graphite 100 -- --
Carbonisation Of Solid Fuels
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Coal Analysis Coal Analysis --Typical Indian CoalsTypical Indian CoalsProximate AnalysisProximate Analysis
Unit Design Coal
Worst Coal
Best Coal
Fixed carbon % 22.0 20.0 25.0 Volatile matter % 21.0 19.5 23.0 Moisture % 15.0 16.5 14.0 Ash % 42.0 44.0 38.0 Total % 100.0 100.0 100.0 HHV Kcal/kg 3300 3000 3600
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Unit Design Coal Worst Coal Best Coal Carbon % 33.73 30.90 38.26 Hydrogen % 2.35 2.09 2.49 Oxygen(difference) % 5.48 5.00 5.96 sulphur % 0.37 0.36 0.38 Nitrogen % 0.75 0.85 0.57 Moisture % 15.00 16.50 14.00 Ash % 42.00 44.00 38.00 HARD GROVE INDEX 55 54 56
Coal Analysis Coal Analysis --Typical Indian CoalsTypical Indian CoalsUltimateUltimate AnalysisAnalysis
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Ash Characteristics Ash Characteristics --Typical Indian CoalsTypical Indian Coals Design Worst Best
Initial Deformation Temp. Deg.C 1150 1100 1200
Hemispherical Temp. Deg.C 1400 1400 1400
Fusion Temp. Deg.C 1400 1400 1400 Ash Analysis: A – SiO2 % 60.08 61.40 60.30 A – Al2O3 % 29.50 28.50 29.80 B – Fe2O3 % 4.10 3.90 4.70 B – CaO % 1.70 1.93 1.57 B – MgO % 0.75 0.92 0.59 B – Na2O + K2O % 0.65 0.85 0.53 A – TiO2 % 1.70 1.60 1.80 - P2O5 % 0.80 1.10 0.13 - SO3 % 0.27 0.31 0.25
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Ash AnalysisAsh Analysis
Provides indicators to
Slagging / fouling / deposition potential
Erosion potential
Corrosion potential
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SLAGGING INDICESSLAGGING INDICES( based on a typical design stage input)( based on a typical design stage input)
Design Coal Worst Coal Best Coal
Base / Acid Ratio
0.11 Low 0.11 Low 0.15 Low
Iron / Calcium Ratio
1.32 High 1.39 High 4.86 Severe
Silica / Alumina Ratio
2.13 Medium 2.26 Medium 2.20 Medium
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Normally specified Coal Properties
Proximate Analysis
Ultimate Analysis
Calorific Value
Ash Constituents
Ash Fusion Temperatures
Hard Grove Index
YGP Index
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Moisture and ash free
C (%) O + N (%) H (%)
Wood 50 44 6
Peat 55-64 39-35 5-7
Brown Coal 60-75 34-17 4-8
Bituminous Coal 78-90 19-4 4-6
Anthracite 94-98 3-1 1-3
Graphite 100 -- --
Carbonisation Of Solid Fuels
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Coal Analysis Coal Analysis --Typical Indian CoalsTypical Indian CoalsProximate AnalysisProximate Analysis
Unit Design Coal
Worst Coal
Best Coal
Fixed carbon % 22.0 20.0 25.0 Volatile matter % 21.0 19.5 23.0 Moisture % 15.0 16.5 14.0 Ash % 42.0 44.0 38.0 Total % 100.0 100.0 100.0 HHV Kcal/kg 3300 3000 3600
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Unit Design Coal Worst Coal Best Coal Carbon % 33.73 30.90 38.26 Hydrogen % 2.35 2.09 2.49 Oxygen(difference) % 5.48 5.00 5.96 sulphur % 0.37 0.36 0.38 Nitrogen % 0.75 0.85 0.57 Moisture % 15.00 16.50 14.00 Ash % 42.00 44.00 38.00 HARD GROVE INDEX 55 54 56
Coal Analysis Coal Analysis --Typical Indian CoalsTypical Indian CoalsUltimateUltimate AnalysisAnalysis
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Ash Characteristics Ash Characteristics --Typical Indian CoalsTypical Indian Coals Design Worst Best
Initial Deformation Temp. Deg.C 1150 1100 1200
Hemispherical Temp. Deg.C 1400 1400 1400
Fusion Temp. Deg.C 1400 1400 1400 Ash Analysis: A – SiO2 % 60.08 61.40 60.30 A – Al2O3 % 29.50 28.50 29.80 B – Fe2O3 % 4.10 3.90 4.70 B – CaO % 1.70 1.93 1.57 B – MgO % 0.75 0.92 0.59 B – Na2O + K2O % 0.65 0.85 0.53 A – TiO2 % 1.70 1.60 1.80 - P2O5 % 0.80 1.10 0.13 - SO3 % 0.27 0.31 0.25
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Ash AnalysisAsh Analysis
Provides indicators to
Slagging / fouling / deposition potential
Erosion potential
Corrosion potential
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SLAGGING INDICESSLAGGING INDICES( based on a typical design stage input)( based on a typical design stage input)
Design Coal Worst Coal Best Coal
Base / Acid Ratio
0.11 Low 0.11 Low 0.15 Low
Iron / Calcium Ratio
1.32 High 1.39 High 4.86 Severe
Silica / Alumina Ratio
2.13 Medium 2.26 Medium 2.20 Medium
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Coal reactivityCoal reactivity
1.181.41FC/VMFuel ratio (6) % (4)6
31.039.5%FC5
37.025.5%Ash4
26.328.0%VM3
5.57.0%Moisture2
Proximate
42004980Kcal/KgCV1
Coal 2Coal 1
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HEAT RELEASE PROFILES OF Coal 1 & Coal 2 (courtesy - Mr. K. Nandakumar AGM R & D / BHEL, Trichy.
30405060708090
100110
0 2 4 6 8 10 12
TIME IN MINUTES
% H
EAT
REL
EASE
Coal 2 Coal 1
Heat from VM
Heat from FC
2
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Coal petrography gives a better insight into coal combustion behaviourModelling studies will help in understanding the effect of variables like combustion regime, ash quantity, fineness etc.Characterisation of coals by Pilot scale testing and comparing with unit operating data will help in predicting the performance for similar coals more accurately
Furnace Absorption Prediction
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Combustion Heat Release RateCombustion Heat Release Rate
Fixed Carbon/Volatile Matter ( FC/VM) fromthe Proximate analysis
provides an insight into the reactivity of the coal lower the FC/VM ratio , better thecombustibilty ( generally)
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Emissivity & Absorptivity Of Ash
Radiative heat transfer properties influence furnace absorptionAbsorptivity & emissivity will decide the heat absorption in water wallVaries with ash constituents and prevailing furnace environment
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Ash Ash quantityquantityInfluences the furnace heat transfer by shielding the radiation.
Higher the ash quantity, greater the shielding of furnace walls
Flame temperature lowered by increased ash quantum
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PulverisedPulverised fuel finenessfuel fineness
Finer particles promote faster
heat release by ensuring better
access to oxygen in the Furnace
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Boiler AuxiliariesBoiler AuxiliariesMills
More number of bigger size mills required for low grade coals; wear resistant materials to improve the life of wear parts
FansLarge PA fans are required to meet the primary air requirement.ID fans are provided with replaceable wear liners considering the erosive nature of Ash in the flue gas stream.
Air HeatersAccelerated seal erosion due to erosive ash; double seal arrangement to reduce leakage
Dust collectorsIncreased dust burden and high ash resistivity calls for larger size of electrostatic precipitators.
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Boiler EfficiencyBoiler Efficiency
This is influenced by coal properties, ambient temp. & relative humidity,Boiler exit gas temp.
Determines the heat input to the boiler
Forms the basis for air & gas weight
calculations,quantity of coal fired
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Boiler Efficiency Boiler Efficiency (contd..)(contd..)
Every 20degc increase in exit gas temp. reduces the boiler efficiency by 1%
Increase in excess air by 1%reduces the boiler
efficiency by 0.04%
Higher moisture and higher H2 content and lower
calorific value of coal decreases the boiler efficiency
-1%H2 increase leads to approximately 1.3% loss
and 1%M increase leads to 0.2%loss in efficiency
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Effect Of Ash On Boiler Design
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Boiler Design At Various Ash Levels
5694124Ash kg / Mkcal fired505050HGI
431536103400kcal/kgHHV
243442%Ash
141312%M
252222%VM
373124%FC
Proximate Analysis
Washed Coal-2
WashedCoal-1
ROM unwashed
Coal
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%Ash 42 34 24
Weight Base -7% -11%
SG package cost Base -6% -10%
Boiler weight and cost