Hamid Arastoopour Linden Professor of Engineering and Director of - - PowerPoint PPT Presentation

Hamid Arastoopour

Linden Professor of Engineering and Director of Wanger Institute for Sustainable Energy Research (WISER) Illinois Institute of Technology, Chicago, IL

 Prof. Hamid Arastoopour (PI)  Prof. Javad Abbasian (Co‐PI)

• Emad Abbasi (PhD Candidate)
• Shahin Zarghami (PhD Candidate)
• Emad Ghadirian (PhD Student)
• Jaya Singh (PhD Student)

The overall objective of the program is to develop a Computational Fluid Dynamic (CFD) model and to perform CFD simulations to describe the heterogeneous gas-solid absorption and regeneration and WGS reactions in the context of multiphase CFD for a regenerative magnesium

• xide-based (MgO-based) process for simultaneous

removal of CO2 and enhancement of H2 production in coal gasification processes.

3

The Project consists of the following four (4) tasks:

• Task1. Development of a CFD/PBE model accounting for the particle

(sorbent) porosity distribution and of a numerical technique to solve the CFD/PBE model.

• Task2. Determination of the key parameters of the absorption and

regeneration and WGS reactions.

• Task3. CFD simulations of the regenerative carbon dioxide removal

process.

• Task4. Development of preliminary base case design for scale up

WGS Reaction CO2 Removal Fuel Gas CO2

Conventional

WGS Reaction & CO2 Removal Fuel Gas CO2 T: 350°-500°C P: 10-70 bar

Integrated

Concentrated Hydrogen Stream Hydrogen Polishing Fuel Cells, Transportation Impurities Chemical Syn./ Liquid Fuels Concentrated Hydrogen Stream

WGS Reaction & CO2 Removal CO + H2O CO2 + H2 XO + CO2 XCO3 Clean Coal Gas Concentrated Hydrogen Stream Sorbent Regeneration XCO3 XO + CO2 CO2

XO make up

Sorbent Preparation, Characteristics and Reactivity

8

2 4 6 8 10 12 14 0.1 0.2 0.3 0.4 0.5

CO2 Capacity, g of co2/100 g of sorbent

K/Mg Molar ratio

0.5 M K2CO3 0.7 M K2CO3 1 M K2CO3 2 M K2CO3

Preparation Parameters HD52‐P2 Sorbent particle diameter, m 150‐180 Calcination temperature, C 520 Calcination temperature ramp, C/min 1 Duration of calcination, hr 8 Concentration of potassium carbonate in the impregnation solution, mol/lit (M) 1 Duration of impregnation, hr 20 Drying temperature, C (post‐impregnation) 90 Humidity during drying, % ambient Duration of drying, hr 24 Re‐calcination temperature, C (post‐drying) 470 Calcination temperature ramp, C/min 1 Duration of re‐calcination, hr 4

9

10

T T

P P P P MFC MFC P

CO2

N2

Data Acquisition & Control System Pressure Regulator Bubble Flow meter Vent

11

0% 10% 20% 30% 40% 50% 10 20 30 40 50

MgO Conversion, % Time, min

Old sorbent New sorbent

12

2 4 6 8 10 12 14 5 10 15 20 25 30 35 40 45 50 CO2 Capacity. Gco2/100g of sorbent

time, min

450 ˚C 425 ˚C 490 ˚C 390 ˚C 340 ˚C

13 0% 10% 20% 30% 40% 50% 60%

5 10 15 20

MgO Conversion, % Time,min

Initial Gas Composition

CO2/N2/H2O: 50/20/30 %mol* CO2/N2/H2O: 50/40/10 %mol* CO2/N2/H2O: 50/45/5 %mol* CO2/N2/H2O: 50/50/0 %mol P=20 bar T=420 ˚C

*The sorbent is exposed to steam for 30 min prior to the run.

 Structural changes  Secondary Carbonation Reaction

• MgO + H2O = Mg(OH)2

Hydration

• Mg(OH)2 + CO2 = MgCO3 + H2O

Carbonation

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15

0.01 0.1 1 10 100 175 225 275 325 375 425 475 525 575 PCO2 & PH2O , bar Temperature, ˚C Absorption

MgO+CO2 MgCO3

Decomposition

MgCO3 MgO+CO2

Hydration

MgO+H2O Mg(OH)2

Dehydration

Mg(OH)2 MgO+H2O

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0% 10% 20% 30% 40% 50% 60% 280 300 320 340 360 380 400 420 440 460

MgO Conversion, % Temperature, C

Gas Composition

CO2/N2/H2O: 50/20/30 %mol CO2/N2/H2O: 50/50/0 %mol P=20 bar Reaction Time= 5 min

MgO+CO2 = MgCO3 Mg(OH)2+CO2 = MgCO3 +H2O

• A. Hassanzadeh, 2007

20 µm Scale:

1.E-07 1.E-06 1.E-05 1.E-04 1.E-03 100 200 k, (cm/min) Radius of Particle (μm)

k2 k1

Low Reactive Zone (k2) Highly Reactive Zone (k1) Product Layer Gas Film rp, k1 rc k2

rp’ Abbasi et al., Fuel, 2013 3

) 1 ( ZX X r r

p p

   

product react react product

M M Z      ) 1 1 1 ( ) 1 ( 1 ) 1 )( ( 3

3 3 1 3 2

XZ X X X r D k X C C N k r dt dX

p g s e b

• MgO

s p

         

c c s

r r for k r r for k k   

2 1

) (



X D D

g g

 

Coupled Computational Fluid Dynamics (CFD) Population Balance Model (PBM ) (CFD‐PBM)

Eulerian- Eulerian Approach in combination with the kinetic theory of granular flow Assumptions: Uniform and constant particle size and density ‐ Conservation of Mass

‐ gas phase: ‐ solid phase

‐ Conservation of Momentum

‐ gas phase: ‐ solid phase

‐ Conservation of Momentum

‐ gas phase: ‐ solid phase

‐ Conservation of solid phase fluctuating Energy

‐ solid phase

g g g g g g

m v t



     ) .( ) (    

s s s s s s

m v t



     ) .( ) (     ) ( . ) .( ) (

s g gs g g g g g g g g g g g

v v g P v v v t                      ) ( . ) .( ) (

s g gs s s s s s s s s s s s s

v v g P P v v v t                       

Numerical Modeling: Conservation Equations

j i s s s i s s

R y v y t      ) .( ) (    

j i g g g i g g

R y v y t      ) .( ) (    

Generation of energy due to solid stress tensor Diffusion dissipation

s s s s s s s s s s

v I p v t                       ) .( : ) ( ] ) .( ) ( [ 2 3

Abbasi and Arastoopour , CFB10, 2011

Gas-solid inter-phase exchange coefficient: EMMS model Accounts for cluster formation by multiplying the “Wen & Yu” drag correlation with a heterogeneity factor

Heterogeneity Factor ω < 1



sg



) ( ) 1 ( 4 3

g D s g g p g g

C u u d       

p s g g g p g g g

d u u d          ) 1 ( 75 . 1 ) 1 ( 150

2 2

74 . 

g

 74 . 

g

  ) (

g

 

0044 . ) 7463 . ( 4 0214 . 5760 .

2 

  

g

 0040 . ) 7789 . ( 4 0038 . 0101 .

2 

  

g



g

 8295 . 32 8295 . 31   82 . 74 .  

g

 97 . 82 .  

g

 97 . 

g



Numerical Modeling: Drag Correlation

(Wang et al. 2004) Li et al., Chem. Eng. Sci, 2012

) , ; ( )] , ; ( [ ] ) , ; ( ) , ; ( [ )] , ; ( ) , ( [ ) , ; ( t h t f t x t f t D x t f t u x t t f

j j i pt i p i

x ξ x ξ x ξ x ξ x ξ x x ξ                  

Accumulation term + Convection term + diffusive term + Growth term = Source term

To account for particle density distribution changes due to the reaction

Finite size domain Complete set of trial functions Method Of Moments: FCMOM

• Finite size domain: [-1, 1] instead of [0,∞]
• Solution in terms of both Moments and size distribution
• f(ξ,x,t) will be approximated by expansion based on a complete set of trial

functions

 

    

      

n v n v v n n n n n n

v v n n v v n c x t C t x f

2

}. ] )! ].[( )! [( 1 .{ ] )! 2 [( )! 2 ( . ) 1 ( . 2 1 . 2 1 2 when ) ( ). , ( ) , , (       d f

i i

. ) .(

1 1





  ) ( . 2 1 2 ) (   

n n

P n  

2 / )] ( ) ( [ } 2 / )] ( ) ( [ {

max min max min

t t t t          

Strumendo and Arastoopour, 2008

) ( ) . .( IG MB MB v t

Conv p i i

         

 Implementation in Ansys /Fluent code via User Defined

Scalars and Functions

i s i s i s s i s p s s i s s s

S D v t



               ) .(

CFD Multiphase Model

Phase velocity, Volume Fraction Mean particle size PBE terms Moments of size Distribution

Population Balance Model

Reaction

Assumption: Moments are convected with mixture velocity

K v t

p

     .

min min

 

) .( ) ( }. ). 1 ( ] . ) 1 ( {[ ) .( ) ( }. . ] . ) 1 ( {[ ) .( ) ( 1 }. ). 1 ( ] . ) 1 ( {[ ) .( ) ( 1 }. . ] . ) 1 ( {[ ] [

min min max , 1 1 1 min min max , 1 1 1 min min max 1 1 1 min min max 1 1 1 , j j p i i j j p i i i i i i i j p j i

x v i f f x v i f f dt d i f f dt d i f f v x t                                          

           

                 

2 ) ( ) )( (

max min min max 1

          

s

vg= vs= 1 m/s εs = 0.2

f2 f f1 1m

1st Moment 2nd Moment

1  0.5  0.5 1 5 10 15

Particle Property (Dimensionless) Number density function (Dimensionless)

I  ( ) f  ( ) f1  ( ) f2  ( ) 

t = 10s

f2 f f1 1m Inlet Outlet center point

Preliminary Base case design and Simulation Results

45 cm 30 cm

Thermocouple Thermocouple

8 cm 7 cm

T1 Thermowell Bed of Sorbent Quartz Beads SS Annulus SS Annulus Frit Reactor Body T2 T1 T2

420 425 430 435 440 445 450 455 5 10 15 20 25 30 35 40 45 50 Time, min Temperature, C T11 T12 T13 T14

420 425 430 435 Bed Temp., C Position of the bed, cm 8 4

8 cm 2 cm T11 T12 T14 T13 Thermowell

420 425 430 435 Bed Temp., C Position of the bed, cm 8 4

8 cm 2 cm T11 T12 T14 T13 Thermowell

CO2 Absorption Breakthrough Curve at Different Operating Temperatures

0.5 1 1.5 2 2.5 3 3.5 4 5 10 15 20 25 30 35 40 Time, min CO2 Outlet Flow, mol/min*103

Sorbent: EP68 System Pressure= 20 atm Inlet Total Flow Rate= 200 cm 3 /min CO2 inlet= 50 %mol N2 inlet= 50 %mol 450°C 425°C 350°C Bed Inlet Bed Outlet

Initial 150 sec 1000 sec 2400 sec

MgO mass fraction

Based on DOE/ NETL Carbon Capture Unit. (Courtesy of Larry Shadle, NETL)

3.35 m

Location Nominal Design gas Flow (g/s) Adsorber 5 Loop seal 1 0.7 Loop seal 2 0.8 Regenerator 1 Move air 0.14

NETL experimental images every 0.4-0.6 sec

Clark et al., Powder Tech. 2013

“Chugging occurs when a large mass of particles lifts from the fluidized bed and moves into the cone leading into the riser. The cone‐constriction prevents particles from flowing smoothly into the riser and particles plug the riser pipe.”

 Modeling, simulation and base design

• Development of a modified frictional granular flow model and

Completion of cold flow full loop CFB simulations for solid circulation rate calculations.

• completion of riser simulation by including reaction and population

balance model for density changes.

• Development of preliminary base case design for scale up

 Experiments

• Effect of CO2 and H2O concentration on absorption reaction and
• perating condition on regeneration reaction
• Modeling of regeneration process and combined absorption & WGS

reactions

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Task 1. Task 2. Task 3. Task 4. Month 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 Milestones: Task completion Experimental work completed Reaction model finalized CFD simulation of single reaction/reactor Completed CFD simulation of integrated process Completed Development of the base-case design completed