Examples of the Application of Computational Fluid Dynamics II

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Examples of the Application of Computational
Fluid Dynamics - II

• Eric G. Eddings
• Dept. of Chemical Engineering
• University of Utah

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Example - Cu Smelting Cyclone

• Series of problems to be addressed
• Severe erosion problem in feed tuyeres
• Severe accretion buildup in smelting cyclone
• Operation at 50 capacity
• Dust carryover
• Corrosion

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Copper Smelting Cyclone

• Four Feed-Material Tuyeres (copper concentrate)
• Four Oxy-Fuel Burners (natural gas oxygen)

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Cyclone Reactor Flow Characteristics
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Simulation Outputs

• Particle Dispersion Deposition
• Gas Velocity Field
• Heat Transfer
• Local Gas Properties
• Local Particle Properties
• Particle Histories
• Local Wall Properties

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Accretion Buildup

• Controlled by Deposit Rheology, Particle
  Temperature Deposition Rate
• Will Deposit Flow Freely?
• temperature
• composition
• Are Particles Reacted?
• reaction rates
• heat transfer
• residence time

Deposition Rate
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Metal Wastage

• Surface Damage from Material Loss, Warpage, etc.
• Controlled by Acid Attack, Erosion, Local Hot
  Spots
• Model with Local Temperature, Stoichiometry
  Mass Flux

Temperature
Stoichiometry
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Dust Carryover

• Controlled by Cyclone Flow Characteristics
• centrifugal force (velocity mass)
• residence time
• Small Particles (lt10 mm) Hard to Capture
• thermophoresis other transport mechanisms?

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Parametric Studies

• Alterations evaluated
• Burner modifications
• Tuyere modifications
• Geometry modifications
• Burner/tuyere combinations
• Key considerations
• Accretion buildup
• Corrosion
• Dust carryover

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Cyclone Oxy-Fuel Burner
O2 holes 11/16 ID

• Redesign Burner to Change Heat Transfer
  Characteristics
• Impacts Concentrate Reactions

O2 holes 1/2 ID
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Geometry Changes

• Conical bottom
• various angles
• similar to traditional cyclones
• Dished head
• reduce roof erosion
• Roof Burner/Tuyere

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Results - Parametric Studies

• Conical bottom, burner modifications
• reduced accretions, dust carryover in simulation
• implementation brought production up to 120
• Dished Head, Top burner
• evened out temperature distribution, reduced
  corrosion
• dust carryover increased
• went back to previous configuration

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Example - Cement Kiln

• Presence of reduced clinker near exit of kiln
  resulting in lower quality clinker product
• Determine cause of apparent reducing conditions

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Cement Kiln - 2D Simulation
Recirculation Zone
Kiln exit
Recirculation Zone
Recirculation Zone
Velocity Magnitude
Secondary air through cooler grate
Recirculation Zone
(25 ft/s)
Recirculation Zone
(0 ft/s)
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Other Examples
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Energy
SNCR Injection - Upper Portion of 500 MW
Coal-Fired Boiler
Coal-Fired Cyclone - NOx Control
Evaluation of NOx and LOI in Coal-Fired Boiler
Waterwall corrosion in Coal-Fired Boiler
Reagent Injection for SO2 Removal
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Minerals
Lead/Zinc Smelter - Kivcet Process
Tertiary Air Injection - Cement Kiln
Ore Nodulizing Kiln
Copper Smelting - Inco Furnace
Coal Injection - Blast Furnace Tuyere
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Chemicals
Xylene Reboiler
Ethylene Heater
De-coking process - Ethylene Furnace
Continuous Catalyst Renerator