Gas-Liquid Packed Bed Reactors in Microgravity

Vemuri Balakotaiah, University of HoustonBrian J. Motil, NASA Glenn Research Center

Mark J. McCready, Notre Dame UniversityYasuhiro Kamotani, Case Western Reserve University

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https://ntrs.nasa.gov/search.jsp?R=20040142365 2018-05-25T08:58:04+00:00Z

Why Packed Bed Reactors in Microgravity?

MotivationPacked Bed is the ‘workhorse’ of the Chemical Industry. – Used to carry out many single and multiphase reactions– Used in many Unit Operations (Gas Absorption/Purification,

Extraction/Leaching, Adsorption/Chromatography, etc.)

Considered an “enabling technology” for long duration manned space flights– Water Recovery (catalytic beds/biological reactors) Critical Technology

– Air Revitalization (CO2 absorption) Severely Limiting[Workshop on Critical Issues in Microgravity Fluids, Transport and Reaction Processes, NASA-TM-212940-

2004]

NASA funded grants and projectsUniversity of Houston, V. Balakotaiah (Principal Investigator).– M. McCready, U. of Notre Dame, – B. Motil, NASA GRC; Y. Kamotani, CWRUPurdue University, S. Revankar (Principal Investigator).AHLS-1 flight definition experiment.

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Trickle Flow

Bubbly Flow

Spray Flow

Pulse Flow

Solid packing coated with Liquid Film

Continuous Gas Phase

Liquid Droplets

Continuous Liquid Phase

Bubbles

Alternating Gas/Liquid Phases

Flow Regimes in 1-g co-current downflow

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Similarities and Differences Between 1-g and 0-gCocurrent Downflow Through Packed Beds

Low Interaction Regime (trickle flow) does not exist without gravity.

All fluid flow is driven by pressure gradient with capillary and shear forces playing a more significant role. No steady countercurrent flow.

Pulse flow occurs at a much lower flow rate and enhances interaction.

Liquid holdup in 0-g is 100%

Pressure drop measured in 0-g is the true frictional pressure drop

Spray flow is inertia driven and not effected by change in gravity.

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First Experiments in 0-g

12 flights - over 300 test conditions flown on NASA KC-135 aircraft (20 sec/run)Rectangular cross section2.5 cm x 5 cm x 60 cm long

5 differential pressure trans. (1000 Hz)2 mm and 5 mm spherical glass beadsHigh speed video (500 fps)Air and Water-Glycerin (1 to 20 cP)0.03 < G < 0.8 kg/(s m2)3 < L < 50 kg/(s m2)0.18 < ReLS < 1008.5 < ReGS < 1754 x 10-4 < WeLS < 0.2900 < SuL < 365,000

G

pGSGGS

LS

LS

L

LppLSL

L

pLSLLS

dUWe

dSu

dUdUµµµµ

ρρρρµµµµ

σσσσρρρρσσσσ

ρρρρµµµµ

ρρρρ==================== Re Re WeRe

2

2

2

LS

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-4

0

4

kPa

1918171615141312 seconds

1.00.80.60.40.20.0P

ower

/Fre

q.

14121086420Hz

-4

0

4

kPa

1918171615141312 seconds

2.01.51.00.50.0P

ower

/Fre

q.

14121086420Hz

-4

0

4

kPa

1918171615141312 seconds

2.01.51.00.50.0P

ower

/Fre

q.

14121086420Hz

-4

0

4

kPa

1918171615141312 seconds

15

10

5

0Pow

er/F

req.

14121086420Hz

Identification of Flow Regime Transitions

Pulse flow “near” transition

Bubble flow “near” transition

Pulse flow

Bubble flow

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0.1

1

10

100

(G/L

) (ρ l/ρ

g)av

e

0.1 1 10 100 10001 / (We + (1/Re))

Bubbly Flow Bubbly/Pulse Transition Pulse Flow

Packed Bed in Microgravity

Upper and Lower Boundaryfor Bubbly/Pulse Flow Predicted by Talmor

Upper and Lower Boundary Observed for Bubbly/Pulse Flowin Microgravity

Microgravity Experimental Results Compared to Talmor Map

Re11

11

inte ++++

++++====

++++++++====

We

FrviscousrfacegravityinertiaX

*gD])([Fr )(*Re )(* 2

LG

LG

LG GLGLDGLDWe ννννµµµµσσσσ

νννν ++++====++++====

++++====

)/(1)/(GL

GL GLLG ++++

++++====νννννννννννν

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Flow Regime Transition in Microgravity

101

102

103

104

105

106

Su L

0.01 0.1 1 10 100ReGS / ReLS

Bubbly FlowPulse Flow

ReG / ReL = 700 x SuL-2/3

0.1

1

10

100

Re L

S

5 6 7

102

2 3 4 5 6 7

103

2 3 4 5 6 7

104

2 3 4 5

(ReGS / ReLS) * SuL2/3

Bubbly FlowPulse Flow

Transition (K = 700)

2LS LS P L

L 2LS LS L

Re Re dSuCa We

ρ σµ

= = =

Bubble-Pulse transition is a function of gas and liquid Reynolds numbers and the liquid Suratman number, where:

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1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

aver

age

pres

sure

dro

p (k

Pa)

1.00.80.60.40.20.0G (kg/ s m2

)

Pulse

Spray

Bubbly

Normal Gravity Microgravity

Water, 5mm PackingL = 15 (kg/s m2

)

Comparison of average pressure drop for normal and microgravity conditions.

Pressure Drop

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Pressure Drop

Scatter is increased in the microgravity environment, an indication of the degree to which the capillary or surface tension effects are masked by hydrostatic head.

567

1

2

3

4567

10

L

0.12 3 4 5 6

12 3 4 5 6

102 3 4 5 6

100

Normal Gravity

L = 1+ 1/ + 1.424/ 0.576- 14%

Ergun Constants: = 118.2, = 1.0

+ 14%

567

1

2

3

4567

10

L

0.12 3 4 5 6

12 3 4 5 6

102 3 4 5 6

100

Microgravity

L = 1 + 1/ + 1.424/ 0.576

Ergun Constants: = 118.2, = 1.0

- 20%

+ 50%

Lockhart-Martinelli Correlation

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Pressure Drop

Dimensionless pressure drop:

2 2

1fP LGS

L LS LS LS

P d Su , ,Re ,Z U Re Re

ερ

−∆ =

Apply limiting cases in terms of the Ergun equation:1. In limit of zero interfacial tension between fluids, reduces to single phase.2. In the limit of zero gas flow, reduces to single phase.3. In the inertia dominated limit, the friction factor should be independent of

the interfacial and viscous terms.

( )2

TP SP 2

111

cbaLGS

LS LS

SuRef fRe Re

εεγε

− − − = − Determining parameters by regression, reduces to (two-phase friction factor):

( )21

3 32

TP 2

11 180 0 8 1 81 1

LGSP

L LS LS LS

SuReP df . .Z U Re Re

εε ερ ε ε

−−∆ − = = + + − −

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1

2

46

10

2

46

100

2

46

1000

fTP

1 10 100 1000ReLS / (1 - )

Single Phase Ergun Equation

ReGS / (1- ) = 33ReGS / (1- ) = 65ReGS / (1- ) = 99ReGS / (1- ) = 131ReGS / (1- ) = 180ReGS / (1- ) = 267

Su = 900

1

2

46

10

2

46

100

2

46

1000

fTP

1 10 100 1000ReLS / (1 - )

Single Phase Ergun Equation

ReGS / (1- ) = 14ReGS / (1- ) = 27ReGS / (1- ) = 40ReGS / (1- ) = 55ReGS / (1- ) = 74ReGS / (1- ) = 114

Su = 9200

1

2

46

10

2

46

100

2

46

1000

fTP

1 10 100 1000ReLS / (1 - )

Single Phase Ergun Equation

ReGS / (1- ) = 14ReGS / (1- ) = 35ReGS / (1- ) = 67ReGS / (1- ) = 100ReGS / (1- ) = 135ReGS / (1- ) = 180ReGS / (1- ) = 270Su = 23,000

1

2

46

10

2

46

100

2

46

1000

fTP

1 10 100 1000ReLS / (1 - )

Single Phase Ergun Equation

ReGS / (1- ) = 13ReGS / (1- ) = 26ReGS / (1- ) = 40ReGS / (1- ) = 53ReGS / (1- ) = 72ReGS / (1- ) = 106Su = 146,000

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Pressure Drop & Pulse Characteristics with varying g

• Pulse amplitude decreases with increasing gravity.

.5 psi1.69 psi2.22 psiPulse Amplitude

.6 psi4.75 psi4.15 psiAverage Pressure Drop

DifferenceHigh Gravity (32-40 s)

Microgravity (10-18 s)

-5.5

-5.0

-4.5

-4.0

-3.5

-3.0

psi

403020100 seconds

DP5 - 224021

MicrogravityHigh-g (~1.8)

DevelopingFlow

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Flow Regimes and Pressure Drop with Alumina/Catalyst Particles [Summer, 2004] Flow Regimes and Pressure Drop with Structured Packed Beds (2-D beds and monoliths) [Summer/Fall 2004]Mass Transfer Studies in Microgravity

Gas-liquid interfacial areaGas to liquid mass transfer coefficientSolid-liquid mass transfer coefficient

Modeling/Computational and Scale-up Studies

B.J. Motil, V. Balakotaiah & Y. Kamotani, “Gas-Liquid Two-Phase Flow Through Packed Beds in Microgravity”, AIChE J.,49,557-565 (2003)

Work in Progress

Summary

Flow regime and pressure drop data was obtained and analyzedPulse flow exists at lower liquid flow rates in 0-g compared to 1-g1-g flow regime maps do not apply in microgravityPressure drop is higher in microgravity (enhanced interfacial effects)

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