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Project 1481
Ash Behavior in E-Gas Gasification Systems Training Workshops
Presented to:
Reliance Industries Ltd.
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Presentation Overview Agenda for Workshop
Microbeam – description of company
Capabilities
Databases
Tools – Analysis, testing, mechanisms, and modeling
Workshop goal and objectives
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Subject Areas
1. Fuel impurities and measurement
2. Impurity transformations in gasification systems
3. Impurity transport and deposit growth in gasification systems
4. Managing/predicting ash behavior in gasifiers and syngas coolers
3
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Day 1. Workshop Overview and Subject Area 1. Fuel impurities and measurement
900 Introductions
930 Workshop Overview
1030 WS - 1 - Fuel Impurities: Fuel impurities - abundance and forms in Fuels
11:30 WS - 2 - Fuel Impurities Measurement: Fuel impurities - Methods of measurement – Overview
1230 Lunch
1330 WS - 3 - Standard methods of Measurement - Standards for analyzing fuel impurities
1430 WS - 4 - Advanced methods (minerals) - Scanning electron microscopy and x-ray diffraction
1530 Break
1600 WS - 5 - Advanced analysis (organic bound) - Chemical Fractionation
1730 WS - 6 - Review literature on subject area -- Discussion/Questions
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Day 2. Subject Area 2: Impurity transformations in gasification systems
900 Introductions
930 WS - 7 - Mineral forms - Thermal properties of mineral phases
1030 WS - 8 - Organic impurity forms - Thermal properties of organically associated elements
1130 WS - 9 - Gasification process - Partitioning impacts - slag formation/deposit growth
1230 Lunch
1330 WS - 10 - Impurity transformations-coarse ash particle formation and coalescence - coarse particle formation
1430 WS - 11 - Impurity transformations-fine particle formation through release of organically associated elements and vaporization/condensation
1530 Break
1600 WS - 12 - Impurity transformations-ultrafine particle formation - Homogeneous and heterogeneous condensation
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Day 3. Subject Area 2: Impurity transformations in gasification systems (continued)
900 Introductions
930 WS - 13 - Ash particle size composition - Particle size composition distribution (PSCD) of ash
1200 Lunch
1300 WS - 14 - Fuel type Impacts on PSCD - Impacts of coal rank and fuel properties
1500 Break
1530 WS - 15 - Review literature on subject area 2
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Day 4. Subject Area 3: Impurity transport and deposit growth in gasification systems
900 Introductions
930 WS - 16 - Intermediate Transport - Ash particle and vapor phase transport mechanisms
10:30 WS - 17 - Bonding phases/flow behavior - Chemistry and physical properties of phases responsible for ash bonding/sticking/flow
1200 Lunch
1300 WS - 18 - Corrosion layer - Steel/Alloy corrosion processes
1500 Break
1530 WS -18 - Continued
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Day 5. Subject Area 3: Impurity transport and deposit growth in gasification systems (Continued)
900 Introductions
930 WS - 19 - Ash particle sticking mechanisms - Sticking mechanisms - surface and particle properties - deposit growth
1030 WS - 20 - Initial layer composition - Impacts of vapor phase species on initial layers
1200 Lunch
1300 WS - 21 - Ash particle sticking -- Particle properties
1500 Break
1530 Discussion/ Questions
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Day 6. Subject Area 3: Impurity transport and deposit growth in gasification systems (Continued)
900 Introductions
930 WS - 22 - Sintering processes - General sintering processes in gasifiers
1030 WS - 23 - Sintering processes - high temp Sintering with reactive liquids - silicate based sintering/crystallization
1200 Lunch
1300 WS - 24 - Sintering processes - Low temp Sintering with less reactive liquids - sulfide and halogen based sintering
1500 Break
1530 WS - 25 - Sintering processes - Gas/Solid Sintering with less reactive liquids - pore filling - molecular cramming
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Day 7. Subject Area 3: Impurity transport and deposit growth in gasification systems (Continued)
900 Introductions
930 WS - 26 - Deposit thermal properties - Heat transfer through deposits - Dependency on deposit properties
1030 WS - 27 - Development of a captive surface -- Deposit surface properties - sintering liquid phase formation - slag flow behavior
1200 Lunch
1300 WS - 28 - Review literature on subject area -- Literature in this area will be provided and reviewed
1500 Break
1530 General discussion – review of key chemical and physical process important to managing/predicting
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Day 8. Subject Area 4: Managing/predicting ash behavior in gasifiers and syngas coolers
900 Introductions
930 WS - 29 - Past evolution of PC and CFB - Fuel type impacts on system design - Gasifier/syngas coolers
1030 WS - 30 - Ash formation -- Models to predict the particle size composition distribution in gasification systems
1130 WS - 31 - Slag flow -- Models to predict the flow behavior of ash/slag (T250, T80, TCV)
1230 Lunch
1330 WS - 32 - Transport models -- Models to predict the transport of ash particles to surfaces
1500 Break
1530 WS - 33 - Growth/sintering - Models to predict ash particle sticking behavior/growth/strength development
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Day 9. Subject Area 4: Managing/predicting ash behavior in gasifiers and syngas coolers (continued)
900 Introductions
930 WS - 34 - Deposit thermal property -- Models to predict deposit thermal properties
1030 WS - 35 - Integrated models -- Application of combustion system models to gasification - CFD based
1130 WS - 36 - Simplified integrated models - Advanced indices for gasifiers/syngas coolers
1230 Lunch
1330 WS - 37 - Deposit shedding - Impacts of fuel properties and operating parameters
1500 Break
1530 WS - 38 - On-line cleaning -- Force required to remove deposit - peak impact pressure
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Day 10. Subject Area 4: Managing/predicting ash behavior in gasifiers and syngas coolers (continued)
900 Introductions
930 WS - 39 - On-line cleaning - Effectiveness of soot blower, horn, pulse detonation, thermal shock etc
1030 WS - 40 - Additives to manage fouling - Overview of additives such as clays, bauxite, kaolinite, magnesium oxide etc
1130 WS - 41 - Synthetic slag formulations - Synthetic slags to optimize slag flow and minimize ash deposition
1230 Lunch
1330 WS - 42 - Laboratory methods -- Laboratory support for Reliance Gasification Technologies
1500 Break
1530 WS - 43 - Review literature on subject area
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Microbeam Technologies Inc. Commercial spin-off from the University
of North Dakota
Mission Provide advanced combustion and
gasification system analysis and consulting services to minimize the impact of fuel impurities on combustion and gasification system performance
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Experience Base Conducted over 1480 projects for utilities, coal
companies, power system developers, and research organizations worldwide since 1992
Advanced tools to predict the impacts of fuel impurities on gasification and combustion system performance
Analysis of fuels, fly ash, corrosion products, deposit characteristics ~10,000 samples
Behavior of inorganic components in combustion and gasification systems
Characterization and optimization of system operating conditions
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Experience – Plant Performance Fuel properties – Coal (brown to anthracite), petroleum (coke and
fuel oils), biomass (wood, grasses…), waste wood (hog fuels), waste paper
Sorbent properties – limestone attrition and reactivity testing
Plants
Combustion – PC, cyclone, fluid bed
Air pollution control systems – NOx (staging, SNCR, SCR), SO2/SO3 (SDA, WFGD, DSI), particulate (ESP, FF), Mercury (oxidation, sorbents)
Gasification – entrained flow, fixed bed, fluid bed, transport reactors
Advanced systems – chemical looping
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Examples of Recent Projects Cyclone fired combustion systems
Impacts of NOx reduction strategies on slag flow, ash partitioning (particulate loading), fouling/slagging
Fuel properties – fuel selection and blending
Entrained flow gasification
Synthetic slag formulations for Pet coke fired slagging gasifiers
Syngas cooler fouling
Pulverized coal fired systems
Blending to manage fuel properties
Slag deposit strength for ash handling systems
Particulate control – ash resistivity and cohesivity
Fluidized bed combustion
Small scale combustion testing - Ash properties – pH and leachability
Bed agglomeration management for pet coke, biomass, waste combustion
Mercury control
Impacts of oxidizing agents – Hg capture and corrosion issues
Additives for reduction of fine particulate and deposit formation
Roadmap – Technology applications for the ND lignite industry
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Microbeam Capabilities Fuel characterization techniques
Computer-controlled scanning electron microscopy
Chemical fractionation
Deposit/slag characterization techniques
Morphology
Scanning electron microscopy point count – viscosity/porosity
High temperature equipment
Slag flow
Refractory corrosion testing – static and dynamic testing
Pilot and full-scale testing equipment
Syngas cooler fouling simulator
Deposit recovery
Limestone attrition and reactivity testing
Plant performance assessment
Sampling fly ash (impactors/filters), slag, deposits
Modeling and predictive methods
Viscosity versus temperature for slag
Predictive indices for slag flow, ash deposition, ash handling, particulate control
Training
Impacts of fuel properties on plant performance
Advanced analysis methods to analyze fuels and associated materials
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Workshop Goal and Objectives Goal is to provide Reliance Industries personnel with a
fundamental understanding of the behavior of ash-related materials that will facilitate reliable and efficient operation of the E-Gas gasification system.
Objectives include providing the following information
Detailed workshop summary document
Copies of slides used in the lectures
Presentation of lectures on specific topics
Research papers and other reports.
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Fuel Properties
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1. Initial Fuel
Coal
Wood (waste, bark, chips,
saw dust), sunflower hulls,
Rice hulls, corn stover,
Bagasse, switch grass,
Yard waste,
Cl, P
Na+,K
+
Amorphous
silica
Biomass Petroleum Coke
Transformations – Fuel Impurities
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Ash formation during Oil/Petcoke Conversion
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Oil Ash Particle Size Distribution Miller and Linak, 2002
Transport Mechanisms
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Ash Transport to Heat Transfer Surfaces
The transport of intermediate ash species (inorganic vapors, liquids, and solids) is function of:
State and size of the ash species
System design – burner type, heat transfer surface configuration
System conditions such as gas flow patterns, gas velocity, and temperature
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Ash Transport Mechanisms
eddy
Sticking
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Heat transfer
surface
Ash
Fe0
Fe0
Fe0
Fe0
Fe0
Fe0
Fe0
Fe0
Fe2+
Fe0
Fe0
Fe2+
Fe2+
Fe2+
S2-
S2-
S2-
S2-
S2-
Growth – Bonding Phases
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Ash intermediate transport and deposition
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Vapor phase
Homogeneous
condensation
Heterogeneous
condensation
Na
S
Cl
K
P
Fe
Ni
Zn
SO2
SO3
Aerosols
(0.02 – 0.2 µm)
Fuel Impurity Derived
Materials from Combustion
Process – Vapors, liquids,
and solidsQuartz
Clay
Pyrite
Calcite
Organic Ca
Coalescence
Fragmentation
shedding
Steel Tube
Corrosion and bonding
layer - Gas-solid reaction
Sulfide rich layer
Layered Deposit Transport Process Ash Intermediates – gas liquid and solid
Diffusion
Thermophoresis
Inertial Impaction
Sintered layer - Gas-solid reaction, molecular
cramming-expansion due to reaction of S with
Deposited particles,
Ostwald ripening
Sulfate coated particles and sulfate pore filling
SO2/
SO3
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Bonding/Sticking Phases P
ha
se
Ab
un
da
nce
1200 ºF
FeS (1810 ºF)
ZnS (>1450 ºF)
Na-FeS (~1380 ºF)
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Sintering – strength development
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Viscosity versus temperature for day 2 ash
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Significant strength would develop at temperatures above 1900 ºF. The materials would flow at about 2200 ºF
Measured T250 – 2045 ºF
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Sintering
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Transport of Particles <5 µm – Forming the Initial Deposit Layers
Benson and others, 1993
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Formation of Deposit Outer Layers Via Inertial Impaction and Capture Due to a Captive Liquid Phase
Benson and others, 1993
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Transport of particles <5 µm, forming the initial deposit layers
Steel Tube
(T = 540°C/1000°F)
Fly Ash and
Products of Combustio
n
T gas= 2000°F
V gas= 25 ft/
sec
Vapor-Phase and
Small-Particle Diffusion
Flue Gas Boundary Layer,
Particle Size <5 mBenson and others, 1993
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Sticking Probability – ash
particle size
Huang and others, 1996
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Transport and sticking of inner sinter layer or
intermediate layer of the deposits
Fly Ash and
Products of Combustio
n
Rebounding Particles
Liquid in Deposits Due to
Temperature IncreaseBenson and others, 1993
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Formation of deposit outer layers via inertial impaction and capture due to a captive liquid phase
Molten Captive Surface
Benson and others, 1993
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Captive surface
Amorphous material filling spaces between fly ash particles
Melting, assimilation, and chemical interactions
Captive surface
Benson and others, 1993
Thermal Properties
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Effect of temperature and ash properties on thermal conductivity
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The ash materials A, B, C, and D represent ash materials of varying composition. Ash A has sodium content of 5% The slag – was molten The particles – not sintered – represents the boundaries for thermal conductivity
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Deposit Strength and Porosity Kaliazine and others, 1997
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Mechanism of Heat transfer and deposit growth
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Ni and Others*
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Slag formation and Flow
Partitioning
Impurities
Gas, liquid, solid
Impurity Transport
Diffusion, Thermophoresis
Inertial Impaction
Impurity materials
Interaction
Refractories
Metals
Impurity
accumulation
Growth
Sintering
Flow
Impurity
Accumulation
Thermal behavior
Strength
Heat transfer
surface
Ash
Fe0
Fe0
Fe0
Fe0
Fe0
Fe0
Fe0
Fe0
Fe2+
Fe0
Fe0
Fe2+
Fe2+
Fe2+
S2-
S2-
S2-
S2-
S2-
Syngas
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Slag Layer Thickness Calculation
Solid Slag
Liquid Slag
Twall
T250
Tsurface, gas
Vapors, fine, and non-impinging particles
Heat Flux- Volatiles and Char Gasification
XT = k • (Tgas – Twall) / H
Assim Slag
Xs = k • (T250 – Twall) / H
TAssim Xa = k • (Tgas – Tassim) / H
Xl = XT - Xa - Xs
Syngas Cooler Wall
Slag Layer Formation Model Solid Slag Liquid Slag
Twall T250 Tsurface, gas
Impingement Rate (char + ash particles)
Gas
Slag Flow
xi
viscosityi
Shear forcei = density • g • xi
Slag flow ratei = Sheari • xi / Viscosityi
Deposition rate = Ash impingement rate • sticking fraction
Sticking fraction = 0 for viscosity > log10 5.5 poise 0 to 1 for viscosity log10 5.5 -250 poise
Accumulation rate = Deposition rate – Slag flow rate
Slag flow rate = density • average(Slag flow ratei )
Heat Flux- Volatiles and Char Combustion
Gasifie
r Wall
Modeling Ash Behavior
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Partitioning
Impurities
Gas, liquid, solid
Impurity Transport
Diffusion, Thermophoresis
Inertial Impaction
Particle Sticking
Coefficients
Deposit
Accumulation
Surface sticking
Coefficient
Growth/Erosion
Heat Transfer
Thermal/mechancial
properties
Growth/shedding
Impinging Flow
Non-Impinging Flow
Processes – chemical,
physical properties and
thermal mechanical
behavior
Algorithms to predict the
size and composition
distribution of the ash
Fuel composition
Size, composition, type,
and abundance of mineral
grains
Abundance of organically
associated elements
Viscosity Calculations –
Particle size fractions
High temperature sintering
processes
Viscosity, surface tension,
particle size, time
Porosity/density
Tensile Strength
Thermal conductivity
Low temperature (<800 ºC)
Sulfide/halogen bonding
Warn Gas
Filter