Hamid ArastoopourLinden Professor of Engineering and Director ofWanger 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 aComputational Fluid Dynamic (CFD) model and toperform CFD simulations to describe theheterogeneous gas-solid absorption andregeneration and WGS reactions in the context ofmultiphase CFD for a regenerative magnesiumoxide-based (MgO-based) process for simultaneousremoval of CO2 and enhancement of H2 productionin 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 tosolve 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

CO2Removal

Fuel Gas

CO2

Conventional

WGS Reaction &

CO2 Removal

Fuel Gas

CO2

T: 350°-500°CP: 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

0

2

4

6

8

10

12

14

0 0.1 0.2 0.3 0.4 0.5

CO

2C

apac

ity, g

of c

o2/1

00 g

of s

orbe

nt

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 8Concentration of potassium carbonate in the impregnation solution, mol/lit (M) 1

Duration of impregnation, hr 20Drying 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 49

10

T

T

P P

P P

MFC

MFC

P

CO2

N2

Data Acquisition &Control System

PressureRegulator

Bubble Flow meter

Vent

11

0%

10%

20%

30%

40%

50%

0 10 20 30 40 50

MgO

Con

vers

ion,

%

Time, min

Old sorbent

New sorbent

12

0

2

4

6

8

10

12

14

0 5 10 15 20 25 30 35 40 45 50

CO

2C

apac

ity. G

co2/

100g

of s

orbe

nt

time, min

450 ˚C425 ˚C

490 ˚C

390 ˚C

340 ˚C

13

0%

10%

20%

30%

40%

50%

60%

0 5 10 15 20

MgO

Con

vers

ion,

%

Time,min

Initial Gas CompositionCO2/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

14

15

0.01

0.1

1

10

100

175 225 275 325 375 425 475 525 575

PCO

2 &

PH

2O ,

bar

Temperature, ˚C

AbsorptionMgO+CO2 MgCO3

DecompositionMgCO3 MgO+CO2

HydrationMgO+H2O Mg(OH)2

DehydrationMg(OH)2 MgO+H2O

16

0%

10%

20%

30%

40%

50%

60%

280 300 320 340 360 380 400 420 440 460

MgO

Con

vers

ion,

%

Temperature, C

Gas CompositionCO2/N2/H2O: 50/20/30 %molCO2/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 µmScale:

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

0 100 200

k, (c

m/m

in)

Radius of Particle (μm)

k2

k1

Low Reactive Zone (k2)

Highly Reactive Zone (k1)

Product Layer

Gas Filmrp,       k1

rc k2

rp’

Abbasi et al., Fuel, 2013

3 )1( ZXXrr pp

productreact

reactproduct

MM

Z

)

111()1(1

)1)((3

331

32

XZXXXr

Dk

XCCN

kr

dtdX

pg

s

eboMgO

s

p

c

cs rrfork

rrforkk

2

1

)(0XDD gg

CoupledComputational 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

gggggg mvt

).()(

ssssss mvt

).()(

)(.).()( sggsggggggggggg vvgPvvvt

)(.).()( sggsssssssssssss vvgPPvvvt

Numerical Modeling: Conservation Equations

jisssiss Ryvyt

).()(

jigggigg Ryvyt

).()(

Generation of energy due to solid

stress tensor

Diffusion dissipationssssssssss vIpv

t

).(:)(]).()([

23

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(

43

0 gDsggp

gg Cuud

p

sggg

pg

gg

d

uu

d

)1(75.1

)1(150 2

2

74.0g

74.0g

)( g

0044.0)7463.0(40214.05760.0 2

g

0040.0)7789.0(40038.00101.0 2

g

g8295.328295.31

82.074.0 g

97.082.0 g

97.0g

Numerical Modeling: Drag Correlation

(Wang et al. 2004)

Li et al., Chem. Eng. Sci, 2012

),;()],;([]),;(),;([)],;(),([),;( thtftx

tftDx

tftuxt

tf j

jipt

ip

i

xξxξxξxξxξxxξ

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

vnv

vnnn

nn

n

vvnnvvnc

xtCtxf

02

0

}.])!].[()![(

1.{])!2[(

)!2(.)1(.21.

212

when )().,(),,(

df ii .).(

1

1

)(.2

12)( nn Pn

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

maxmin

maxmin

tttt

Strumendo and Arastoopour, 2008

)()..( IGMBMBvt Convpi

i

Implementation in Ansys /Fluent code via User Defined Scalars and Functions

is

is

iss

ispss

isss SDv

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

Kvt p

. min

min

).()(

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

).()(

}..].)1({[

).()(

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

).()(

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

min

minmax

,1

11

min

minmax

,111

min

minmax1

11

min

minmax111,

j

jpi

i

j

jpi

i

ii

ii

ijpj

i

xv

iff

xv

iff

dtd

iff

dtd

iffvxt

2

)())(( maxminminmax0

1

s

vg= vs= 1 m/s

εs = 0.2

f2 f

f1

1m

1st Moment 2nd Moment

1 0.5 0 0.5 1

0

5

10

15

Particle Property (Dimensionless)

Num

ber d

ensi

ty fu

nctio

n (D

imen

sion

less

)

I ( )

f ( )

f1 ( )

f2 ( )

t = 10s

f2 f

f11m

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

0 5 10 15 20 25 30 35 40 45 50Time, min

Tem

pera

ture

, C

T11T12T13T14

420 425 430 435Bed Temp., C

Posi

tion

of th

e be

d, c

m

0

8

4 8 cm

2 cm

T11

T12

T14

T13

Thermowell

420 425 430 435Bed Temp., C

Posi

tion

of th

e be

d, c

m

0

8

4 8 cm

2 cm

T11

T12

T14

T13

Thermowell

CO2Absorption Breakthrough Curve at Different Operating Temperatures

0

0.5

1

1.5

2

2.5

3

3.5

4

0 5 10 15 20 25 30 35 40Time, min

CO

2 Out

let F

low

, mol

/min

*103

Sorbent: EP68System Pressure= 20 atmInlet Total Flow Rate= 200 cm 3 /minCO2 inlet= 50 %molN2 inlet= 50 %mol

450°C

425°C

350°C

Bed Inlet

Bed Outlet

Initial             150 sec             1000 sec         2400 sec            

MgO m

ass frac

tion 

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 imagesevery 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 

operating condition on regeneration reaction Modeling of regeneration process and combined absorption & WGS 

reactions

32

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 completionExperimental work completedReaction model finalized CFD simulation of single reaction/reactor CompletedCFD simulation of integrated process CompletedDevelopment of the base-case design completed