chemical reaction engineering laboratory introductory remarks milorad p. dudukovic and m.h....

CHEMICAL REACTION ENGINEERING LABORATORYIntroductory Remarks

Milorad P. Dudukovic and M.H. Al-Dahhan

Annual MeetingAnnual MeetingOctober 24, October 24,

20022002

S1

CHEMICAL REACTION ENGINEERING LABORATORY

OUTLINEOUTLINE

Washington University (WU) and the School of Engineering and Applied Science (SEAS)

Chemical Reaction Engineering Laboratory (CREL)

CREL Active Research Areas

Future Research Initiatives

Events for the Day

S2

Selected Facts

6,509 undergraduates 5,579 graduate and professional students, 1,384 part-time students Washington University offers more than 90

programs and nearly 1,500 courses in a broad spectrum of traditional and interdisciplinary majors.

$1,104,962,000 million in revenue

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RawRawMaterialsMaterials

Chemical Chemical TransformationTransformation

Materials withMaterials withNew PropertiesNew Properties

Petroleum & Petrochemicals Chemicals Materials Biotechnology Semiconductor Etc.

Proper Engineering of Kinetics + Transport Interactions=

Increased Energy & Material Efficiency + Lower Capital Expenditure+ Waste Minimization+ Lower Operating Cost+ Pollution Prevention+ Increased Safety

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CREL ObjectivesCREL Objectives

Education and Training

Advancement of reaction engineering methodology

Application and transfer of improved reaction engineering methodology to industrial practice

Assisting industry in new state-of-the-art technology development

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Petroleum Refining

PolymerManufacture

EnvironmentalRemediation

Syn & Natural Gas Conversion

BulkChemicals

Fine Chemicals& Pharmaceuticals

HDS, HDN, HDM,Dewaxing, Fuels,Aromatics, Olefins, ...

MeOH, DME, MTBE,Paraffins, Olefins,Higher alcohols, ….

Aldehydes, Alcohols,Amines, Acids, Esters,LAB’s, Inorg Acids, ...

Ag Chem, Dyes,Fragrances, Flavors,Nutraceuticals,...

Polycarbonates,PPO, Polyolefins,Specialty plastics

De-NOx, De-SOx,HCFC’s, DPA,“Green” Processes ..

Value of Shipments:

$US 637,877 Million

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REACTION ENGINEERING QUANTIFIES THE INTERACTIONS BETWEEN REACTION KINETICS

AND TRANSPORT PHENOMENA (MOMENTUM, MASS AND HEAT TRANSFER) IN VARIOUS REACTOR

TYPES.

)T,C(R)C(L bbb

j

bbjjRbh TCRHTL j ),()()(

transport;kineticsf00 P,C,T

P,C,T

feed, Q

product, Q

REACTOR PERFORMANCE = f ( input & operating variables ; rates ; mixing pattern )

REACTOR MOLECULAR SCALEEDDY/PARTICLE

MOLECULAR SCALE (RATE FORMS)

Strictly Empirical

Mechanism Based

FundamentalElementary Steps

REACTOR SCALE

Ideal ReactorsPFR / CSTR

Empirical ModelsAxial Dispersion

CFDPhenomenologicalModels

EDDY OR PARTICLE SCALE TRANSPORT

Empirical Part ofRate Equation

Thiele Modulus &Effectiveness Factor

DNS / CFDEmpirical Micromixing Models

RigorousMulticomponent Transport

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Computer Tomography (CT)Computer Tomography (CT)

• Measurement of the time-averaged cross-sectional phase holdup (volume fraction) distribution

• 100 mCi Cs-137 source emitting gamma radiation

• NaI(TI) detectors• 5 detectors in a 18o fan-beam (single

view), with 7 projectors per detector, for the present experiment (6in. column)

• 99 views• 3645 projections were used to

reconstruct the solids holdup distribution at each cross-sectional plane

• Estimation-Maximization (EM) algorithm used for image reconstruction

• Spatial Resolution 2 mm• Density Resolution 0.04 g.cm-3

CHEMICAL REACTION ENGINEERING LABORATORYS8


Devanathan (1990)

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INVESTIGATED MULTIPHASE REACTORS

L

L

S

S

LIQUID-SOLID RISER BUBBLE COLUMN STIRRED TANK

G

G

S. ROY, A. KEMOUN N. DEVANATHAN, S. DEGALEESANY. YANG, S. KUMAR, B.C. ONG

A. RAMMOHAN, V. RANADE


EXAMPLES OF REACTOR SCALE MODELS FOR MULTIPHASE CONTACTING IN REACTORS WITH TWO MOVING PHASES

IDEAL REACTOR CONCEPTS:

A) PLUG FLOW (PFR)

U1

U2k

1

2

B) STIRRED TANK (CSTR)

U1

U2

k1

2

C) AXIAL DISPERSION MODELD) NEED MORE ACCURATE FLOW & MIXING DESCRIPTION VIA

1) PHENOMENOLOGICAL MODELS2) CFD MODELS (EULER-EULER FORMULATION)3) MODEL VERIFICATION: HOLDUP DISTRIBUTION AND VELOCITY FIELD


HOPPE

R

R

I

S

E

R

EDUCTOR

High Pressure Side (80-100 psi)

Low Pressure Side ( <80 psi)

WATER TANK

PUMP

RECYCLE LINE

611"

6

PP

P

P

911"


Tim

e-A

vera

ged

Solid

s H

old

up

0 1 2 3 4 5 6 7

S/L = 0.10

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

z = 50 cmz = 100 cmz = 150 cm

(a)

Radial Position, cm

-5

0

5

10

15

20

0 1 2 3 4 5 6 7

Radial Position, cm

Axia

l V

elo

cit

y,

cm

/s

Z = 50 cm

Z = 100 cm

Z = 150 cm

S/L = 0.10

Deff solids RTDDzz, Drr CARPT

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MODELS FOR REACTOR FLOW PATTERNIN LIQUID-SOLID RISER

UL

Us

Deff

kLs

UL

US

Dsz

1

12ks

2kLs

kLs1

US2

UL

Us

Dz

Dr

kLs

ADM TWO ZONE 2-D CONVECTIONDIFFUSION


Dsz

S13

CHEMICAL REACTION ENGINEERING

LABORATORY

Three-Dimensional SimulationThree-Dimensional SimulationUl = 20 cm/s, S/L = 0.15

-8

-3

2

7

12

17

0 1 2 3 4 5 6 7

Radial Position, cm

Axia

l S

olid

s V

elo

cit

y,

cm

/s

3D Simulation

CARPT: Ul = 20 cm/s; S/L = 0.20

Axial Solids Velocity

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7

Radial Position, cm

Solid

s H

old

up

Simulation: Ul = 20 cm/s; S/L = 0.15

CT Data: Ul = 20 cm/s; S/L = 0.15

Solids Holdup

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6 7

Radial Position, cmGra

nu

lar

Tem

pera

ture

, cm

2/s

2

3D Simulation: Ul = 20 cm/s; S/L = 0.15

CARPT: Ul = 20 cm/s; S/L = 0.15

Granular Temperature

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-8.00

-3.00

2.00

7.00

-8.00 -3.00 2.00 7.00

0

50

100

150

-7.6 -2.6 2.4 7.4

x-Position, cm

z-P

osit

ion,

cm

0

50

100

150

-7.6 -2.6 2.4 7.4

y-Position, cm

z-P

osit

ion,

cm

Trace over 38 s (1900 positions)

Lagrangian Trace (ULagrangian Trace (Ull = 20 cm/s; S/L = 0.15) = 20 cm/s; S/L = 0.15)

-505

t = 60 s t = 70 st = 65 s Time Average(25 - 100 s)

Z = 100 cm

Z = 125 cm

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Overall solids flux - Time-of-flight measurementsOverall solids flux - Time-of-flight measurements

• Solids Mass Flux (Gs) in the downcomer is :

H = 40 cm

sss

A A

sssss

s dAdAA

G ''

t

Hvs

t average time of flight obtained for

number of particle visits

H= 2.2 m

Downcomer

Detectors to get RTD’s of the sections in the loop Solid flux from

the hopper

Scintillation detectors

Sc-46 radioactive particle ( 150 m , 2.55 g.cc-3 )

• Mean velocity can be calculated as

GAS-SOLID RISER AND TIME OF FLIGHT MEASUREMENT SET-UPS16

Radial Solids Hold Profile (Downcomer)

0.4

0.5

0.6

0.7

0.8

0.9

-1 -0.5 0 0.5 1

Dimensionless Radius

So

lid

s h

old

up

Ug = 3.2 (After) Ug= 4 m/s (After) Ug = 4.4 m/s (After) Ug = 5.2 m/s (After)

Results : Densitometry Experiments

• Solids hold-up lie within the 95% confidence intervals after the modification

• Radial solids hold-up profile is flat even near the wall regions

• Mean value = 0.59 (with a STD = 0.001)

59.0s

SOLIDS HOLDUP PROFILE IN THE DOWNCOMER AS DETERMINED BY GAMMA DENSITOMETRY

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Ugriser = 3.2 m/s

Ugriser = 4 m/s

Number of visits

256 277

Mean RTD (sec) 2.47 1.95Standard deviation of RTD (sec) 0.34 0.13

Velocity (mean) (m.s-1) 0.16 0.21Standard deviation of velocity (m.s-1) 0.02 0.01

Overall Solids flux (Kg.m-2.s-1) 26.6 33.7

Standard deviation in solids flux (Kg.m-2.s-1) 1.1 0.5

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50

10

20

30

40

50

60

Time (sec)

Freq

uenc

y

Residence Time Distribution (RTD) for Superficial Gas Velocity of 3.2 m/s

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50

10

20

30

40

50

60

70

Time (sec)

Freq

uenc

y

Residence Time Distribution (RTD) for Superficial Gas Velocity of 4 m/s

Results after secondary air introduction : Time of Flight Experiments

Number of CSTR’s in Series = 53

Number of CSTR’s in Series = 225

SOLIDS RTD IN THE DOWNCOMER AND ESTIMATION OF SOLIDS FLUX IN THE RISER

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Fischer-Tropsch Synthesis Synthesis of methanol Coal hydrogenation Hydrogenation of oils Alkylation of methanol, benzene SO2 removal from tail gas Effluent treatment Wet oxidation of effluent sludge Biotechnological processes Production of single cell protein Animal cell culture Production of biomass Oxidation Chlorination

APPLICATIONSGas Outlet

Gas Inlet

BUBBLE COLUMN REACTORSBUBBLE COLUMN REACTORS


BUBBLY FLOWUG < UG_T

- low holdup - individual bubbles

CHURN-TURBULENT FLOWUG > UG_T

- high holdup - large voids

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Gas Holdup Profile

Liquid Velocity Profile

Dzz

Drr

uz(r)

1-L(r)

0-R R

CARPT-CT Experimental Evidence Indicates For The True CARPT-CT Experimental Evidence Indicates For The True Time-Averaged Flow and Backmixing PatternsTime-Averaged Flow and Backmixing Patterns

uz Ensemble Averaged Liquid Velocity

Measured from CARPT LTime Averaged Liquid Holdup

from CT Measurements Dzz, Drr Assumed to be CARPT Measured

Diffusivities

z

CD

zr

CDr

rrCu

rt

CzzLrrLLz

L

1

z

CD

r

CDCu;

z

CD

r

CDCu rzrr

''rzzzr

''z

CARPT Experiments indicate DCARPT Experiments indicate Dzrzr , D , Drzrz ~ 0 ~ 0

Transient Convection-Diffusion Transient Convection-Diffusion Equation for Liquid MixingEquation for Liquid Mixing


S20

0 100 200 300 400

1 0.8

0.6

0.4

0.2

0 0 100 200 300 400

1 0.8

0.6

0.4

0.2

0

Detector Level 1 Detector Level 2

Comparison of Experimental (Liquid) Tracer Responses with 2D CDM PredictionsComparison of Experimental (Liquid) Tracer Responses with 2D CDM Predictions

Time, sTime, s

No

rmal

ized

Inte

nsi

tyN

orm

aliz

ed In

ten

sity

0 100 200 300 400

0 100 200 300 400

1 0.8

0.6

0.4

0.2

0 0 100 200 300 400

1 0.8

0.6

0.4

0.2

0


1 0.8

0.6

0.4

0.2

0

1 0.8

0.6

0.4

0.2

0 0 100 200 300 400


Wall Injection at N1 (Run 14.6)UG = 25 cm/s, T = 250 C, P = 5.2 MPa


0 100 200 300 400

1 0.8

0.6

0.4

0.2

0 0 100 200 300 400

1 0.8

0.6

0.4

0.2

0


Experimental

Model

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Comparison of Simulated & Experimental Gas Tracer Comparison of Simulated & Experimental Gas Tracer Responses During Liquid Phase Methanol SynthesisResponses During Liquid Phase Methanol Synthesis

Run 14.6

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80 100

Time (sec)

No

rma

lize

d R

es

po

ns

e

Sim_L1

Exp_L1

Sim_L4

Exp_L4

Sim_L7

Exp_L7

Pressure = 50 atmTemperature =250 Deg. CUg = 25 cm/s


Gupta et al., Catalysis Today (2000), 2253, 1-17.

S22


COMPARISON OF COMPUTED (CFDLIB) AND MEASURED DCOMPARISON OF COMPUTED (CFDLIB) AND MEASURED Dzzzz

Dzz(c

m2/

s)

(sec)

Ug = 12 cm/sDc = 8”

S23

Dzz(c

m2/s

)

(sec)

Ug = 10 cm/sDc = 18”


Motor

Detector

Calibration Rod

Radioactive Particle

Particle trajectories Azimuthally Averaged Velocity vector plot :

zr VV x

Plane including baffles

Kinetic energy

Plane including baffles

zr VV x

r (cm)

r (c

m)

VVr x

Disc

Baffles

Plane at the impeller

Blades

CARPT in STR :

results at a glance

Rammohan et al., Chem. Eng. Research & Design (2001), 79(18), 831-844.

S24


Trickle-BedCocurrent Downflow

Packed-BedCountercurrent Flow

Packed -Bubble FlowCocurrent Upflow

G

G

G

L

G G

GL

L

LL L

PACKED BED WITH TWO PHASE FLOW

SIMULATION ADVANCES• Accounting for particle and

reactor scale wetting effect

• Prediction of the porosity distribution effect on flow field

• Description of multicomponent transport

• Ability to simulate periodic operation

Jiang et al., AIChE J. (2002),Jiang et al., Catalysis Today (2001)Khadilkar et al., Chem. Eng. Sci. (1999)

S25

Flow Simulation using ‘Engineering Approach’

Discrete Cell Model (DCM)(Jiang et al., 1999; Holub, 1990)

Computation Scheme:Non-linear multi-variable minimization

Model Capabilities:Porosity distribution / Internal Obstacles / Capillary pressure (surface tension) / Distributor design / Particle initial wetting state (prewetted/nonprewetted)

Sample Results:Single-phase flow system: Chem. Engrg. Sci. (2000), 55(10), 1829Two-phase flow system: Chem. Engrg. Sci. (1999), 54(13), 2409

FLOW MODELING IN PACKED BEDS

Flow Simulation using ‘Fundamental Approach’ (CFDLIB)

(Jiang et al., 1999; Khadilkar, 1998, Kumar, 1995)

Computation Scheme:Non-linear multi-variable minimization

Model Capabilities:Porosity distribution / Internal Obstacles / Capillary pressure (surface tension) / Distributor design / Particle initial wetting state (prewetted/nonprewetted)

Sample Results:Jiang, et al., Chem. Eng. Sci., 2001, 56(4), 1647Jiang, et al., Catalysis Today, 2001, 66(2-4), 209Jiang, et al., AIChE J., 2002, 48(4), 701; 716

S26


Oxidation of Liquid Hydrocarbons (LOR) Clean Energy from Coal Methane Conversion Gas-Solid Riser Trickle Bed Reactor Coupling Exothermic-Endothermic Reactions in

Reverse Flow Reactive and Catalytic Distillation Miniaturization of Experimental Reactors in

Multiphase Systems Industrial Tomography and Tracer Studies Testing of Industrial Scale Bubble Columns

CREL Research InitiativesCREL Research Initiativesfor which Industrial Partners are being Soughtfor which Industrial Partners are being Sought

S27

N. Devanathan - CARPT - Bubble ColumnsY. Yang - CARPT - Bubble ColumnsB.S. Zou - CARPT - Bubble ColumnsS. Kumar - CT-CARPT - Bubble ColumnsS. Limtrakul - CT-CARPT - Ebulated BedsB. Sannaes - CARPT - Slurry Bubble ColumnsS. Degaleesan - CARPT - Bubble ColumnsJ. Chen - CARPT-CT - Bubble Columns, Packed BedsS. Roy - CARPT-CT - Liquid-Solid RiserA. Kemoun - CARPT-CT - Riser, Stirred Tank

Acknowledgement of Significant Past CREL ContributionsAcknowledgement of Significant Past CREL Contributions

B.S. Zhou - Tap Reactor ModelS. Pirooz - Plasma ReactorsV. Kalthod - BioreactorsH. Erk - Phase Change RegeneratorsA. Basic - Rotating Packed BedM. Al-Dahhan - Trickle BedsJ. Turner - Fly Ash and Pollution AbatementS. Karur - Computational CREM. Kulkarni - Reverse Flow in REGASZ. Xu - Photocatalytic DistillationX. Balakrhishnan - Computational CREM. Khadilkar - CFD, Models, Trickle BedsY. Jiang - CFD, Models, Trickle BedsJ-H. Lee - Models, Catalytic DistillationY. Wu - Models (Trickle Beds, Bubble Column)Y. Pan - CFD (Bubble Columns)P. Gupta - Models (Bubble Columns)

CARPT-CT

CFD, Reactor Models & Experiments

S28

ABB LUMMUS

AIR PRODUCTS

BAYER

CHEVRON

CONOCO

CORNING

DOW CHEMICAL

DUPONT

ELF ATOCHEM

ENI TECHNOLOGIES

EXXON - MOBIL

IFP

INTEVEP

MITSUBISHI

PRAXAIR

SASOL

SHELL

SOLUTIA

STATOIL

SYNETIX - ICI

UOP

INDUSTRIAL SPONSORS DURING 2001/2002

S29

S19

CollaboratorsSponsors

CREL WORLD WIDE CONNECTIONSCREL WORLD WIDE CONNECTIONS

S30


CREL’s tasks

To execute first rate technical work To enhance reaction engineering of multiphase systems To provide industrial participants with expertise and tools

needed to deal with problems in multiphase systems To produce first class graduates

Tasks of industrial participants

To leverage resources and ensure company support of CREL To identify areas where our skills and expertise can be used To explore opportunities for joint research with CREL To provide employment for our interns and graduates

SummarySummary

S31

Events of the DayEvents of the Day7:00 - 8:45 a.m. Breakfast / Registration

8:45 - 9:20 a.m. Overview of CREL Activities M.P. Dudukovic

9:20 - 10:00 a.m. Making Friends with Chemical Reactors O. Levenspiel

10:00 - 10:40 a.m. Coffee Break

10:40 - 11:10 a.m. Microreactors P.L. Mills

11:10 - 11:35 a.m. New Control Initiative G. McMillan

11:35 - 12:00 noon Gas-Liquid Flow in Stirred Tanks A. Rammohan

12:00 - 1:30 p.m. Lunch and Discussion

1:30 - 2:30 p.m. Oral Poster Introductions

2:30 - 4:00 p.m. Poster Viewing and Discussions

4:00 - 5:00 p.m. Workshop on Future CREL Initiatives and Industrial Needs

5:00 - 5:45 p.m. Small Groups Ad-hoc Discussions or Visit to CREL Facilities

6:00 - 7:00 p.m. Social Hour

7:00 - 9:00 p.m. Dinner (Banquet)S32

chemical reaction engineering laboratory introductory remarks milorad p. dudukovic and m.h....

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