rheological and engineering properties of orange pulp

8/20/2019 Rheological and Engineering Properties of Orange Pulp

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Rheological and Engineering Properties

of Orange Pulp

Elyse Payne

Juan Fernando Muñoz

José I. Reyes De Corcuera

September 20, 2012


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2

Industry

Dr. Paul Winniczuk

Mr. Thomas Fedderly

Mr. Marcelo Bellarde

Dr. Wilbur Widmer

Acknowledgements


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Background

Increased market demand for fresh-like

pulpy-juices

Orange pulp contributes to texture and other

sensory properties of fruit juices and otherbeverages

− Fresh-like, “natural” perception

Worldwide increased demand for orange

pulp, particularly in Asia An estimate of 300,000 MT of orange pulp

produced in the US (98 lb/ton)


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Finisher

Citrus Pulp Recovery

Pasteurizer

Pulp ~ 500 g/L

Finisher

Extractor

FinisherHydrocyclone

Pulpy Juice+ Defects

Defects

Pulpy juice

Juice

Juice

Pulp ~ 900 g/L

To Frozen

Storage


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Aseptic

Filling

Pasteurizer

Pulp ~ 500 g/L

Finisher

Extractor

FinisherHydrocyclone

Pulpy Juice+ Defects

Defects

Pulpy juice

Juice

Juice

Pulp

~ 900 g/L

Finisher

Citrus Pulp Recovery


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Overall Objectives

To characterize the rheology

• Studies 1 & 2

To determine the thermal properties• Study 3

To characterize heat transfer in a flowing

system• Study 4


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Study 1

Characterize the rheological properties

orange pulp ~ 500 – 800 g/L at 4 – 80 ºC.

(~ Industrial processing conditions)

• Shear stress ( ) vs. Shear rate ().


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Basic Rheological Models

•Newtonian Fluid

•Non-Newtonian Fluid

• Power Law

• Herschel-Bulkleyn

o K )(

n K

)(

Shear rate (s-1) S h e a r s t r e s s ( P a )

S h e a r s t r e

s s (

P a )

Shear rate (s-1)

Power Law

n < 1

Pseudoplastic

n > 1

Dilatant

K = consistency coefficient

n = flow behavior index


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Wall Slippage

• Multiphase systems

• Displacement of the dispersedphase away from the solidboundaries.

• Low viscous liquid layer that actsas a lubricant

Barnes 1995

Shear rate (s-1) S h e

a r s t r e s s (

P a

)


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Solutions to Slippage

Roughened surfaces

Vane geometry

http://www.viscometers.org/Brookfield-Accessories.html

http://www.viscometers.org/Brookfield-Accessories.htmlhttp://www.viscometers.org/Brookfield-Accessories.htmlhttp://www.viscometers.org/Brookfield-Accessories.htmlhttp://www.viscometers.org/Brookfield-Accessories.html


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050

100

150

200

250

300

0 20 40 60 80 100

σ (

P a )

γ (s-1)

() 511 g·L-1

, (■) 585 ·g·L-1

, (▲) 649 g·L-1

and (X) 775 g·L-1

4 °C 80 °C

050

100

150

200

250

300

0 20 40 60 80 100

σ (

P a )

γ (s-1)

80 °C 500 g .L

-1

4 °C 900 g .L

-1

Effects of Temp. and Conc.


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Power Law Parameters

Shear rate rangeof ~ 0-10 s-1

Linear portion

never exceededshear ratesabove 4 s-1

Flow behavior

index (n) Consistency

coefficient (K)

y = 0.26x + 4.59R² = 0.99

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

5

-2 -1 0 1 2 3 4 5

l n σ

ln γ

lnlnln n K


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503 g∙L-1 597 g∙L-1 643 g∙L-1 795 g∙L-1

Temperature

(K)

nK

(Pa.sn)n

K

(Pa.sn)n

K

(Pa.sn)n

K

(Pa.sn)

RSD (%) RSD (%) RSD (%) RSD (%)

277.15 0.42 70.0 0.41 123.5 0.36 137.2 0.39 233.6

24.21 77.9 14.29 51.1 13.20 51.8 28.67 40.1

292.93 0.32 50.5 0.29 91.3 0.40 109.7 0.33 180.1

3.74 60.0 5.30 49.4 22.89 43.5 14.57 51.7

310.60 0.37 50.9 0.34 83.6 0.30 88.9 0.30 146.7

34.56 61.9 35.61 50.9 23.96 47.2 9.06 47.4

330.55 0.37 43.0 0.25 61.5 0.29 78.3 0.23 115.1

34.27 47.9 16.56 48.5 17.95 45.1 4.55 47.6

353.15 0.18 33.0 0.22 59.9 0.22 74.9 0.21 112.6

60.27 55.9 57.01 0.8 40.62 4.3 47.93 11.7


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Effect of Temperature

Arrhenius-type approach

2

3

4

5

6

7

8

0.003 0.0032 0.0034 0.0036

l n K

1/T (K)

)(lnln RT

E A K a


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Apparent E a for K

• Mango Pulp: 8.9-11.8 kJ.mol-1• Tahini (Slippage) 30.3 kJ.mol-1

0.0

4.0

8.0

12.0

16.0

E a ( k J · m o l - 1 )

Concentration (g∙L-1)

500 497 511 600 606 585 637 644 649 793 817 775

(■) Industry 1, (■) Industry 2, (■) CREC.


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(▲) CREC, and (■) Industry 1(♦) Industry 2

Sources of Pulp Variability

•Batch

•Varieties

•Biological material

•Size/maturity•Mechanical

•Type operation

conditions

•Extractor Finisher•Handling conditions

•Time to pasteurization

0

20

4060

80

100

120

0 20 40 60 80

σ ( P

a )

γ (s-1

)

4 ºC, ~ 500 /L


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Effect of Pasteurization

• PME

() unpasteurized and (■) pasteurized

0

200

400

600

800

1000

1200

0 2 4 6 8 10

σ (

P a )

γ (s-1)


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Study 2

Determine pressure drop by capillary viscometry

• Slip coefficient

• Apparent friction factor( )

=−

c

a ff

c

c fc

c

a fe

ccc g

v K

g

v K

g

v K

D g

Lv f

g

vv

g

Z Z g P

222

2

2

)()( 2222212

212

K

v D

n

n nnn

n

n

2

3

13

2Re

Re

16 f For laminar flow


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Experimental Setup

Diaphragm

Pump

Recirculation

Valve

Flow-

meter

Pressure

Transducer

PT01

TT01

FT01

TT02


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Effects of T and Conc.

200

250

300

350

400450

0.E+00 2.E-04 4.E-04 6.E-04 8.E-04

Δ P ( k P a )

Q with slippage (m3.s-1)

0

100

200

300

400

0.E+00 5.E-04 1.E-03

Δ P ( k P

a )

Q with slippage (m3.s-1)

50 ºC

■ 870 ± 7 g∙L-1 ▲ 760 ± 24 g∙L-1

● 675 ± 13 g∙L-1

♦ 569 ± 11 g∙L-1

4 ºC

■ 864 ± 39 g∙L-1

▲ 729 ± 44 g∙L-1

● 644 ± 35 g∙L-1 ♦ 529 ± 3 g∙L-1


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0

1000

2000

3000

4000

5000

6000

200

250

300

350

400

450

500

0.E+00 2.E-04 4.E-04 6.E-04 8.E-04

Δ P

c a l c w / o s l i p a g e

( k P a )

Δ P E

x p

( k P a )

Q (m3.s-1)

871 g.L-1 (□) calculated (■) experimental

761 g∙L-1 ( Δ) calculated (▲) experimental

Experimental vs. Calculated

675 g∙L-1 (○) calculated (●) experimental

569 g∙L-1 (◊) calculated (♦) experimental


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0

1000

2000

3000

4000

5000

6000

200

250

300

350

400

450

500

0.E+00 2.E-04 4.E-04 6.E-04 8.E-04

Δ P

c a l c w / o s l i

p a g e

( k P a )

Δ P E

x p

( k P a )

Q (m3.s-1)

871 g.L-1 (□) calculated (■) experimental

761 g∙L-1 ( Δ) calculated (▲) experimental

Experimental vs. Calculated

675 g∙L-1 (○) calculated (●) experimental

569 g∙L-1 (◊) calculated (♦) experimental

1” Ø, 25 ft, ~ 6.3 GPM ~ 35 psi < P < 65 psi


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Pumping Costs

(watts)W;sJ

skg

kgJ ][W pW

kg

J 660 P W

3m

kg 1,045 psi,100 P

A processor produces 1/20 of Florida’s pulp = 15,000 MT in 200 days 3 shifts

GPM13min

lb 115

s

kg52

h

kg 3,125W

220,11$

c/[email protected],000'h4,800inW375,3452660

100

psiCost


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Pumping Costs

/gal0.06$or/kg0.015$oryr/000,225$

0.5factorefficiency psi,1000PAssuming

220,11$100

Cost

Cost psi

Disclaimer: This is based on a hypothetical case and a number of non-explicit

assumptions were made


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Data Variability

Diaphragm pump

• Fluctuating flow rates• Lower flow rates at higher concentrations

Pulp variability

• Two sample sources-biological material hasnatural variability

• Industrial vs. non-Industrial (handling andstorage prior to pasteurization).


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Conclusions Studies 1 & 2

Non-Newtonian pseudo-plastic fluid with slippageat > 2-4 s-1

T and Conc. have a small effect on n

50 < K < 230 (Pa ∙sn) as Conc. or T E a was moderately affected by concentration and

pulp source

c increaced with flow rate History of product handling (PME) has a huge

impact on pulp rheology

This impact needs to be fully characterized


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Study 3

Determine the thermal properties of high

concentration orange pulp:

• Heat capacity ( ).

• Thermal diffusivity (∝).

• Thermal conductivity ( ).


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Heat Capacity ()

= ∆

= . + . [

∆∆

. ]

[ +∆∆

. ]


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Thermal Diffusivity (∝)

Thermal Conductivity ( )

∝ =

2.405

= ∝ . .


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Results

Pulp

Concentration

(g L-1)

Specific Heat

Capacity

(J kg-1K-1 )

Thermal

Diffusivity

(m2 s-1) x 107

Thermal

Conductivity

(W m-1 K-1)516 ± 6 4025.0 ± 37.1 1.50 ± 0.01 0.63

617 ± 7 4051.2 ± 64.1 1.55 ± 0.02 0.66

712 ± 12 4055.7 ± 32.1 1.56 ± 0.04 0.66

801 ± 13 4068.4 ± 12.5 1.55 ± 0.07 0.65

No significant differences (p > 0.05) between the mean values obtained for

, ∝, and for the different pulp concentrations.


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Study 4

Determine heat transfer characteristics of

HCP pulp in tubular heat exchangers at

selected concentrations and flow rates• Heat transfer coefficients of orange

• Radial temperature profiles (heating and

cooling)


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Experimental Setup

Section of Heat Exchanger

ℎ =

4ln

TT03-07

PT01

TT02

PT02

T0…T 4 T

w

TT01

Tw T0…

T 4

FT01


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Heat Transfer Coefficients

∆= ( )

ln [( )/( )]

=

∆

Distance from center of the inner pipe

T e m p e r a t u

r e

Pulp

inside

the pipe

Metal Heating

Media

Ti

Tw

T∞

ℎ =

4ln

Local

Overall


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Experimental setup


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Results h

Overall heat transfer coefficients as function of velocity and pulp concentration,

in the heating section of heat exchanger.

5 ft/s

Warning! These numbers were calculating flow rates with slippage, hence they

are artificially high, hence inaccurate!


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Temperature Profiles


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Conclusions

Thermal properties (, ∝, and ) of orange pulp were

not significantly different among different concentrations.

Heat transfer coefficients were lower for highly

concentrated pulp due to its “solid-like” flow that caused

higher temperature gradients within the product.

Heat in this fluid is mainly transferred by conduction with

slight convection around the slippage region.


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Thank you

Questions?


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