Prof. Gary T. Rochelle

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Prof. Gary T. Rochelle
CPE 5.462, 2 MS, 8 PhD Projects/funding for MS or
PhD Technology Area CO2 Capture from Flue Gas (
to address Global Climate Change) By Aqueous
Absorption/Stripping Fundamental Areas Mass
Transfer with Reaction in the Boundary
Layer Applied Aqueous Solution Chemistry Aqueous
Thermodynamics Aqueous Reaction Kinetics Applied
Process Simulation
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System for CO2 Sequestration
Disposal Well

Net Power
Power
CaCO
3
CO
2
Coal
Boiler
ESP
FGD
Abs/Str
Flyash
CaSO
4
30 psia Steam
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MEA Absorption/Simple Stripping
CO2
DT10oC
H2O
Rich
Lean
Absorb
Strip
50C
117C
1 atm
2 atm
10 CO2
5 O2
12 H2O
Purge
to
30 MEA
Reclaim
SO2, HCl, NO
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Practical Problems

• Energy 20-40 of power plant output
• Steam for stripping
• Gas pressure drop
• CO2 Compression
• Amine degradation
• 10 of cost
• Environmental impact
• Capital Cost
• 5 x 50 ft diameter absorbers and strippers
• 50 ft packing

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Approaches to Practical Problems

• Better Solvents
• Faster promote by piperazine (PZ)
• Evolve Monoethanolamine (MEA)/ PZ
• Lower DH K2CO3/PZ
• Oxygen scavengers
• Better Processes
• Vacuum Stripping or Vapor recompression
• CaSO4/K2SO4 Precipitation
• Better contacting
• Packing to get G/L area

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Fundamental Problems

• Model Thermo with high salt (K) amine
• Electrolyte NRTL model
• Maximize solvent and CO2 concs
• Measure Mass transfer with chemical reaction
• Find feasible solvent with faster rates
• Measure oxidative degradation/corrosion
• Cu inhibits corrosion, catalyzes degradation

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Applied Problems

• Identify Packing with max area at min cost
• Characterize and model wetted area
• Innovate flowsheets to minimize Q
• Simulate multistage contacting
• Simulate Vacuum stripping
• Control complex chemistry to minimize Q

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Laboratory Projects

• Mass Transfer with chemical rxn K2CO3/EDA
• Wetted Wall Column
• NMR
• Degradation
• Oxidative of Ethylenediamine
• Thermal of MEA/PZ
• Solvent Reclaiming
• Evaporation of PZ/MEA
• Crystallization of CaSO4 or K2SO4

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Pilot Plant Projects

• Validate Models for MEA/PZ
• 16.8-inch x 20 ft Absorber/stripper
• Test and Develop Innovative Packing
• 16.8-inch x 10 ft PVC Absorber
• Low gas velocity
• Demonstrate Process Innovations
• Vacuum Stripping
• Multistage contacting

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Modeling Projects

• Fundamental models for K2CO3/EDA
• Thermodynamics/VLE/Speciation
• Mass transfer with Chemical Reaction
• Integrated Absorber and System Models
• MEA/PZ
• Vacuum Stripping
• Multistage stripper
• System optimization/integration
• Integrate with Power Cycle

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Solvent Alternatives

• Functions
• Capacity by reversible reaction
• Thermodynamics and stoichiometry
• Fast mass transfer kinetics at interface
• Three types of chemistry
• CO3 CO2 H2O ltgt 2 HCO3-
• DH5 kcal/gmol, very slow
• R3N CO2 H2O ltgt HCO3- R3NH
• DH14 kcal/gmol, slow
• 2R2NH CO2 ltgt R2N-COO- R2NH2
• DH22 kcal/gmol, fast

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Reaction Chemistry
System Solvent 3.6 m K2CO3/0.6 m PZ
For Piperazine Species


For Potassium Species
2


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Mass Transfer

• Report as normalized fluxkg
• Extract rate constants
• Use in conjunction with NMR data
• Limited by knowledge of the interface

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Wetted Wall Column
Gas out
ParaffinOil
Liquid in
Gas in
Liquid out
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CO2 Absorption at 60oC
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NMR Speciation Analysis
3.6 m K2CO3/0.6 m PZ, T 333K
PZ(COO-)2
PZ/H
PZCOO-/H
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Degradation Experiment
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Oxidative Degradation

• By Oxygen in flue gas
• Monethanolamine make ammonia
• Piperazine makes ethylenediamine
• Dissolved metal catalyze
• Fe
• Corrosion inhibitors Cu, V5
• Strip O2, add chelating agents, add oxygen
  scavengers

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Pilot Absorber 16.8-inch ID, 20 ft of packing,
SS
1 atm
Lean Solvent
Air Vent/ makeup
Distributor
Blower
CO2 Analyzer
C.W. 15oC
Makeup CO2
40 60oC
Recycle CO2
Rich Solvent
Storage
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Pilot Stripper 16.8-inch ID, 20 ft packing, CS
Rich Solvent
Distributor
CW

Steam
CO2 Recycle
Reflux
Steam
C.W. 15oC
Storage
Lean Solvent
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System Modeling in AspenPlus
Rate-Based contacting RATEFRAC Electrolyte
Thermodynamics Mass Transfer with Chemical Rxn
Simultaneous Heat Transfer Flexible
configuration and conditions
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