Scaling and Agglomeration

in Fluid Beds

Masayuki Horio

Tokyo Univ. of Agri. and Tech.

Koganei, Tokyo

Congratulations! PSRI’s 30yrs Anniversary

Scaling and Agglomeration

in Fluid Beds

25 min from Shinjuku

A best place to escape & concentrate

Koganei ?

Livsville FBC

(FW)

AFBCs

ｗ/ EPDC

Yubari 40t/d gasifier

w/ MHI-EPDC

Battelle’s MSFBC

w/ Mitsui

Some

Background 350MWePFBC

w/ IHI

Yubari de-H2S for

gasifier

w/ IHI-EPDC

Soft Sphere Model with Cohesive Interactions

Normal and tangential component of F collision

and F wall

Surface/bridge force

Rupture joint h c

Attractive force F c

No tension joint

Normal elasticity k n

Normal dumping h n

Tangential dumping h t

k t Tangential elasticity

Friction slider m SAFIRE is an extended Tsuji-Tanaka model

developed by TUAT Horio group

SAFIRE (Horio et al.,1998~)

(Non-linear spring)

t

t n t x

x F F m = n t F F m >

dt dx

x k F n n n n n h - D =

dt dx

x k F t t t t t h - D = n t F F m

km g = h 2 ( )

( ) 2 2

2

ln ln

p + = g

e e

w/wo Tangential Lubrication

w/wo Normal Lubrication

Numerical simulation era coming

soon?

What is it providing us?

DEM (discrete element method) or

DPM (distinct particle method) Demo

Plan of my Talk

1. Introduction

Nature of suspensions/beds and the effect

of Walls that we design

2. Scaling Issues

Derivations and validations

3. Agglomerating Fluidization

Progresses in Binderless Agglomeration

Plan of my Talk

1. Introduction

Nature of suspensions/beds and the effect

of Walls that we design

2. Scaling Issues

Derivations and validations

3. Agglomerating Fluidization

Progresses in Binderless Agglomeration

Fluidlike

nature of

suspension:

no need of

walls but

appreciated

the wall

Plant

design:

trying to get

most out of

the wall

effect

Fluidization

science: high

potential in

developing the

knowledge on

suspension

nature

Confusions

in

definitions

etc.

Phenomenology and Design

Nature and Art (wall effect)

Particle-Particle interactions created by

Particle-Fluid interactions

(Photo by Prof. Joseph) Nature

Particle clustering simulated by Prof. Tsuji

Nature

Particle clustering observed by laser sheet

method (Tsukada & Horio)

Gs=0.018kg/m2s, u0=0.67m/s, Dt=200mm

Nature

Particle clustering in denser

suspensions observed by

internal picturing (Kuroki &

Horio)

Gs=0.21kg/m2s 0.70kg/m2s 1.2kg/m2s

Nature

A set of three

laser sheets

Gas flow

A cup shaped cluster;

to the 3D structure of

suspensions (Kroki &

Horio) Nature

Particle clusters moving to the wall

(Kuroki & Horio (‘94))

Gs=0.22 kg/m2s, u0=0.58m/s, z=1150mm Wall

Effect

Particle clusters viewed by a horizontal laser

sheet (Tsukada, Ito & Horio)

Gs=0.019 kg/m2s, u0=0.74m/s, z=740mm

Nature

Wall Effect

Scanning Laser Sheet

technique and 3D images

(Ito-Horio) Nature

Wall Effect

A phase diagram of particle

suspensions (w/ Dr. Hirama data by Horio)

Fast fluidized beds = super-

critical state of G/S systems

Nature

Hydrodynamics

Particle

behavior

Chemistry

Mechanisms

&

Kinetics

Heat &

Mass

transfer

Good performance

Hydrodynamics

Particle

behavior

Chemistry

Mechanisms

&

Kinetics

Heat &

Mass

transfer

Good performance

Hydrodynamics

Particle

behavior

Heat &

Mass

Hydrodynamics

Particle

behavior

Heat &

Mass

Transfer

Good performance

Chemistry

Mechanis

ms &

Kinetics

Scale-up issues

?

Boundary

Conditions

+ Nature

Good performance

Three Previous Approaches

to the Scaling Law

1. Dimensional analysis

Fitzgerald (1982)

2. Dimensionless parameters in

differential equations which do not contain Dt as an explicit parameter

Glicksman (1982?, 84……)

3. Integrated relationships,

phenomenology and correlations

Horio et al. (1982, 84, 86) Note: Differential Eqs., boundary conditions and

integration gives solutions !

m times

A simple thought experiment (‘82)

ub=[gDb]1/2

ub= ubo [gDb

o]1/2

ubb=u0-umf

bshould remain same

Dt=mDto

Dt=Dto

ub [ gmDbo]1/2

= m 1/2 ubo

Dbo

Db=mDbo

Thought Expmt:

Dc/Db=(b+2)/(b-1)

Db: Bubble diam.

Dc: Cloud diam.

b= ub/(umf/mf)

umf/mf

ub=[gDb]1/2

umf/mf

ub=[gDb]1/2

umf/mf

ub=[gDb]1/2

xm

Gas flow in emulsion phase

1) For Geldart Group B powders, the bubble

fraction, bubble size distribution, solids

circulation and mixing can be made similar

among different scale models if the following

condition is satisfied:

U U m U Umf mf0 0- = - ( )

2) Fluidization behavior of Group A powders,

both bubble distribution and interstitial gas flow

can be made similar if Equation (96b) is

satisfied, in addition to Equation (98).

U m Umf mf=

Horio’s Scaling Law

o

May allow to use

the same solids!

(96b)

(98)

Horio’s Scaling Law and previous bubble correlations

11

2 1 12

1 2

- =-

- - -

C A

p C AC

T C

sl C slu

u u** **

** **

,

** ,

/

( )( ) ( ) (60)

CFB: Area fraction of annulus Extended Capes model by Horio et al. (‘89)

usl: gas-solid slip velocity

Suffix C: core

Horio’sScaling Law

Equation of continuity for gas:

tu+ =( ) 0 (1)

Equation of motion for gas:

( )

f f

u

tu u g p R+

= - - (2)

Equation of continuity for solid particles:

( )

( )11 0

-+ - =

tv (3)

Equation of motion for solids:

( ) ( )

p p s

tg p R P1 1 1- +

= - - - + +

vv v( ) ( )

(4)

where R denotes

R u M

D u

Dtf= - + -

-

( ) ( )

( )v

v1

(5)

with

β=( ) ( ) / p f T

ng u- - -1 1

(mf ≪≦ 1, Richardson and Zaki, 1954 ) (6a)

β=

1 150 1175

2

- -+ -

m

s p s p

fd d

u( )

. v

(≪１, Ergun, 1952 ) (6b)

Anderson-Jackson (’66) model

What happens if

we start from

the governing

equations ?

f

p p

u

t u u

gl

U p

l

U u

U

÷ ÷ + +

+ + -

÷

÷ =

$

$ ( $ $ ) $ $ $ $ $

0 2

0

0

0

0 v

v (86)

( ) $

$ ( $ $ ) $ $ $ 1 0 0

0

0

0

2

0

0

0

2

0

0

-

÷ +

÷

-

÷ -

÷

÷ =

U

t

U l

U

U u

p v

v v v +

v

gl

U v

v

U v

0 2

(87)

where

$ / ( / ), $ / , $ / , $ / t t l U u u U p p U p

0 0 0 0

2 v v v and $ l .

Dimensionless expressions

The representative length should be the plant

scale.

NO!

Remember: We are using same

molecules!

Scaling law should tell us in what

scale level and how much we can

sacrifice the similarity: Plant scale flow

pattern?; bubble/cluster scale?; particle scale?.

Are you trying to

make everything

similar?

When f /p≪1,

$ $ ( $ $) + - =pl

Uu

p

0

0v

= -( ) /1 p Tg u (mf≪≦1)

= -( ) /1 mf p mfg U (mf≦≪1)

l

U

gl

U

U

up T0 0

2

0 1= -( ) (mf≪≦1)

l

U

gl

U

U

Up mf

mf

0 0

2

0 1= -( ) (mf≦≪1)

The flow field in a unit of length scale l, which is

geometrically similar to a reference unit (denoted by

superscript °), can be made similar, if the following four

conditions are satisfied:

l U l U/ /0

2

0

2= (91)

U u U uT T0 0/ /= (mf≪? ≦1) (92a)

U U U Umf mf0 0/ /= (mf ≦ ≪1) (92b)

v v0 0 0 0/ /U U= (93)

f p f p/ /= (94)

U U m0 0 0 0/ = =v / v (95)

u m uT T= (mf≪? ≦1) (96a)

U m Umf mf= (mf≦≪? ) (96b)

d

dm

p

p

p f

p f

=-

-

1 4

1 2

/

/

m

m (Ar≦104)

d

dm

p

p

p f

p f

f

f

=

-

-

(105≦Ar)

(97a)

(97b)

Ret=Ar/18 (Ar<104), Remf=Ar/1650 (Ar<1.9x104)

o

As noted above, the judgment of the dominant

mechanism can be done based on the Archimedes

number Ar. The guideline of Glicksman (1988),

Rep<4

i.e. for the viscosity-dominant regime, can be

disregarded if fluidizing gas velocity U0 is

considered as not being related to the criterion for

particle size selection. In other words, Equations

(97) can be used regardless of the fluidizing gas

velocity.

Prof. Glicksman’s guideline ?

Experimental Validation

Properties of particles

Glass beads dp umf(obsd) umf(Wen-

Yu)

Particles mm m/s m/s

GB376 376 0.112 0.112

GB305 305 0.074 0.075

GB236 236 0.046 0.045

Experimental

Experimental Validation for

Bubbling Bed

Experimental Validation for Bubbling Bed

Solid tracer concentration for the same

dimensionless time

Straight column

Straight column

l/Dt=1/15

Tapered column

Straight column

l/Dt=2/15

Tapered column

l/Dt=1/15

Tapered column

l/Dt=2/15

radial position [-]

radial position [-] PE pellet concentration [%]

PE pellet

concentration [%]

Transient response

t*=t/[Dt/g]1/2

t*=16.2 ; ○: bed A Dt=0.6m,

▽:bed B Dt=0.3m, △:bed C Dt=0.15m

Validation of scaling

law

Radial and axial PE

pellet distribution

Experimental Validation for

CFBs

Experimental results from CFBs A&B

Similarity in Gsmax vs gas velocity

Similarity in Pressure distribution

Similarity in Phase Transition

Characteristics

Similarity in Pressure fluctuation

Similarity in Mesoscale flow structure

lcl: cluster length Voidage in cluster

Scaling

Experiments

Reactor Model

PLAN & IDEAS REAL PLANT

Experiments

using the same

materials and

conditions as

expected for the

real plant

Reaction,Heat

& mass

transfer,

distributor

elements etc.

Hydrodynamics,

Erosion etc.

Key points:

Reduce risks

but save

money &

time

Scale down

the imagined

plant and

organize

sure tests

down up CFD

■Introduction ◇ Agglomerating Fluidization ◇ Previous thoughts and models ◇ Why binderless granulation? ■ Characteristics of PSG and PSG granules ◇ Granules appearance, structure, strength, size and density, operating factors, scale effect ◇ Co-agglomeration and coating ■ Model predictions ■ Applications ◇ Hard metal cutting tool manufacturing ◇ Dry Particle Inhalation ■ Concluding remarks

Agglomerating Fluidization

“Agglomerating Fluidization”

“Agglomerating fluidization is a common mode of fluidization popular in beds of Geldart group C powders, spray granulation, coating or polymerization, metal powder processing at elevated temperatures and combustion or gasification with sticky ash or sorbent particles. However, in such a variety of cases their differences are only in types of cohesiveness, their order of magnitude, the rate of development and the elastic/plastic characteristics of necks between particles. Once interaction forces are properly expressed, it should be possible to mechanistically describe any different kinds of agglomerating fluidization.”

Iwadate and Horio, Fluidization IX, Durango (1998)

Cited by Prof. J.C. Chen of Lehigh U. for a quiz at 10th

ceremony of Fluidization X, Beijin, May 2001.

Def

luid

izat

ion v

eloci

ty [

m/s

] Ash Agglomeration and

Defluidization; ’80s’ experience

Iron particle growth by sintering

Experimental data from self nucleation tests

Wt pct

first cycle

Size, mesh

US std

+20

-20+30

-30+40

-40

Starter

bed

18.2

45.1

36.7

Final

bed

32.1

33.6

18.3

16.0

Final

bed less

oversize

49.4

27.0

23.6

Wt pct

second cycle

Wt pct

third cycle

Starter

beda

55.6

30.0

14.4

Final

bed

42.3

38.1

12.5

7.1

Final

bed less

oversize

66.0

21.7

12.3

Starter

bedb

67.0

22.0

11.0

Final

bed

44.6

36.2

10.1

9.1

Final

bed less

oversize

65.4

18.2

16.4

1500F 87% reduction 1600F 87% reduction

Starting

cast shot

Fines

taken up

Langston and Stephens (1960)

Puzzling

Umf

increase

for fine

powders Data by Sugihara(1966)

and

correlation by Jimbo (1966)

[ Along with their efforts for

establishing Soc. Powder

Tech. Japan]

u m

f

[cm

/se

c]

dp mm]

um

f [cm

/se

c]

CaCO3

3 d 18 m 3 d 18 m u mf = d p

2

+ n2 F pm p

g( - f ) u mf = d p

2

+ n2 F pm p

g( p - ) f

Chronology of Group C issues

1961 Davidson’s Bubble

1966 Jimbo, Sugihara’s umf issue left a question at least to Japanese

1973 Geldart’s Powder classification and ‘Group C’ for cohesive ones

197X Donsi-Massimila(75), Masters-Rietema(77): Cohesion force and fluidized bed behavior

1985 Chaouki et al., Group C fluidization and agglomerate size (da) prediction

1987 Kono et al.: Measurement of force acting on particles

1988 Morooka et al.: Energy balance model for da

1990 Pacek-Nienow: Fine & dense hardmetal powder fluidization

1991 Campbell-Wang: Particle pressure in a FB

1992 Nishii et al.: Pressure Swing Granulation

1993 Tsuji, Kawaguchi & Tanaka: DEM for Fluidized Bed

1998 Mikami, Kamiya & Horio: Numerical simulation of agglomerating FB (SAFIRE)

Iwadate-Horio: Particle pressure / Force balance model to predict da

Green letters: fundamentals

Liquid Bridge formation (SAFIRE model)

droplet

Very slow liquid layer flow

liquid bridge

small

contact angle

large

contact angle

particle collision

particle collision

liquid bridge

6 7 8 9 10

1 2 3 4 5

(a) Dry particles

u0=1.2m/s, dp=1.0mm， p=2650kg/m3

(b) Wet particles (water: 0.54wt%)

Fluidized bed behavior of dry and wet particles

(SAFIRE simulation, Mikami et al., 1998)

Uematsu, Uchida and Zhang (1994)

(a) (b)

50mm 50mm

(a) before binder removal (b) after binder removal

Trace of original granules in alumina compacts

before and after binder removal

Spray Granulation: Pre Granulation is needed to avoid

dusting, sticking to walls & non-stoichiometric charging

Potential of binderless

granulation (1)

Agglomeration: Reduces troubles associated with cohesiveness of

fines (dusting, sticking & poor chemical accuracy);

Increases uniformity of chemical composition of

product granules by decreasing segregation;

Binders: So far necessary to agglomerate but

Provide unnecessary strength to products;

Leave unwanted binder-originated species even

after the de-binder-ing operation;

Binderless ? Yes, because-------

Because It gives weak products;

--Many processes do not need too much strength.--

Contamination-free;

Weaker granules provide higher green densities,

higher composition uniformity and not severe

defluidization;

Possible to granulate hydrophorbic powders / water

sensitive powders;

Well controlled granulation by Pressure Swing

Granulation (PSG; Dalton Ltd. / Fuji Paudal);

Probably possible to make layered structure.

Applications Dry ceramic process, Powder metallurgy, Drugs etc.

Potential of binderless

granulation (2)

Characteristics of PSG and

its product granules

Pressure Swing Granulation: PSG

Nishii et al., U.S. Patent No. 5124100 (1992)

Nishii, Itoh, Kawakami,Horio, Powd. Tech., 74, 1 (1993)

(a) apparatus (b) operation

time[s] 0 7200

15s 1s ② Compaction

interval

① Fluidization

interval

② Compaction

interval ① Fluidization

interval

0.108m

0.41m

Bag filter

Gas tank

Compressor

Compressor

Wall Effect

Group C

powder

Nature

+

Typical examples of PSG

granules

Al2O3 Lactose

PSG granules: weak but strong enough!

Change in PSD of PSG granules in realistic

conditions

PSG

granules

from ZnO

dp=0.57mm

slide

gate

after

1st fall

2nd fall

3rd fall

Particle size [10-6m]

C

um

ula

tive w

eig

ht [%

]

50

0m

m

original

PSG

granules

0 10 20 30 40 500

20

40

60

80

100

dp,sv [mm]

No. 2 7.48

Primary particle size [mm]

Cu

mu

lati

ve

siz

e d

istr

ibu

tio

n [

v%

]

Fig. 4 Size distributions of primary particles

No. 3 4.95

No. 4 4.79

No. 5 4.14

No. 6 3.71

No. 7 2.58

PSG from lactose

Original powders of Lactose (Takano et al. (2001))

1mm

1mm

No. 2

1mm

No. 4

1mm1mm

No. 3

1mm

No. 5 No. 7No. 6

Fig. 6 Microphotographs of PSG granules of lactosePSG from

lactose

#16-1 #16-1#30-1 #30-1

#16-2#16-2#30-2#30-2

#16-1#30-1 #16-2#30-2

500mm

ZnO

Structure of PSG granules Granules split by a needle show a core/shell structure.

(Horio et al., Fluidization X (2001))

E

Superficial gas velocity [m/s]

Me

dia

n d

iam

ete

r [m

1

0-6

]

0.1 150

1.0

1000

500

0.5

Effect of fluidizing gas

velocity on da

Bu

lk d

en

sity o

f g

ran

ule

s [kg

/m3]

Maximum pressure difference for compaction [Pa104]

0.6

1.0

0.8

1.2

2.0 6.0 4.0 0

Factors affecting PSG

granule density

w=0.4kg

0.2kg

with gas velocity, solids charge

and compaction

chamber pressure

-

DQ 500 series

DQ labo

ρ(bulk)=3710kg/m3

angle of repose=34º

DQ200

ρ(bulk)=3800kg/m3

angle of repose=33º

DQ350

ρ(bulk)=3760kg/m3

angle of repose=35º

Scale up

compaction and attrition

bed expansion

bubbling

fines‘ entrainement

air (in bubbling period)

pulse (in reverse flow period)

① ②

cake

filter cleaning & reverse flow period:

Cakes and fines are returned to the bed cleaning-up the filter, and

bed is compacted promoting agglomerates’ growth and consolidation.

bubbling period:

Bed expansion de-agglomerates and compaction, attrition and solids revolution make grains spherical.

Fines are separated and re compacted on the filter.

①

②

What happens in

PSG?

distributor

Numerical simulation of agglomerating fluidization

Iwadate-Horio (Fluidization IX, 1998)

Ha=0.39x10-19 J, dp=1mm, p=30 kg/m3

Ha=4.0x10-19 J

0.0546m

Gas velocity: linear increase from 0-0.25 m/s within t=0.1s, holding for 0.039s and linear decrease within 1.011s

Authors External force/energy

Ekinetic =mumf /22

shearElaminer =3pmumfda2

Fpp

Fcoh,rup

FGa

v=umf

expansion

Chaouki et al.

Morooka et al.

Iwadate-Horio

Cohesion force/energy

p6

FGa = da

ag

3

Fexp =pDbag(-Ps)da

2

2nk

exp = - Ps

Fcoh,rup =24

2

Hada(1-a)

Model

FGa = Fpp

bubble

Fpp =16

2

hwdp1+[ hw

8p Hr

2 3 ]

Comments

Esplit =hw(1-a)da

2

32

adp

2

Esplit

Etotal

Etotal=(Ekin+Elam) =Esplit

Etotal=(Ekin+Elam)

Fexp = Fcoh,rup

No bubblehydrodynamiceffects included.

If 3mumf <hw(1-a)

/(32pdpa),negative da isobtained.

Force balance

Energy balance

Force balance

gravity force≒drag forcevan der Waals forcebetween primary particles

laminar shear + kinetic forceenergy required tobreak an agglomerate

bed expansion force cohesive rupture force

No bubblehydrodynamiceffects included.

Bed expansionforce caused bybubbles isequated withcohesive ruptureforce.

Comparison of previous model concepts

1E-6 3E-6 1E-5 3E-5 1E-4 3E-4 1E-3 3E-3

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

A

B

F coh,rup = H a d a (1- a )

24 2

F exp = 2n k

p D b a g(-Ps)d a 2 ^

stable point

fluidized

unstable point

easy to

defluidize

(a) example force balance and

two solutions

log d a [m]

log

F[N

]

1E-6 3E-6 1E-5 3E-5 1E-4 3E-4 1E-3 3E-3

1E-10

1E-9

1E-8

1E-7

1E-6

1E-5

1E-4

C

saddle point

(b) Limiting size of agglomerates

log d a [m]

log

F[N

]

The critical condition

Force balance of I-H model (Powder Technol., 1988)

and the critical solution

defluidization due to u0=umfa

Fig. 2 Fracture tensile strength mesurement by a micro compression testing machine

0 50 100 150 2000

0.5

1

1.5

2

2.5

3Ff

Displacement [mm]

Lo

ad

[m

Pa]

Ff

A : Elastic and plastic

deformation

B : Elastic brittle fracture

C :Plastic deformation

(a) Example of fracture tensile strength mesurement

(b) Types of mesurements

Ff

Ff

Grain compression test

and typical force

displacement responses

0.01 0.03 0.1 0.3 1 3 10 30 100 10

20 30

50

100

200 300

500

1,000

Iwadate-Horio Chaouki et al.

Morooka et al.

u 0 =0.5m/s

0.3 0.5 1 2 3 5 10

20

50

100

200

500

1,000

2,000

5,000

u 0 =0.5m/s Morooka et al.

IHM

Chaouki et al.

0.01 0.03 0.1 0.3 1 3 10

20

50

100

200

500

1,000

2,000

u 0 [m/s]

0.01 0.03 0.1 0.3 1 3 0.005

0.01

0.02

0.03

0.05

0.1

Morooka et al.

IHM

Chaouki et al.

u 0 =u mf

bubbling bed

fixed bed

da [m

m]

da [m

m]

da [m

m]

Da [m

m]

(a) Effect of primary particle size

(b) Effect of Hamaker const.

(c) Effect of u0

dp [mm]

Ha [J]

(IHM)

Comparison of model

performances

Bubble size

Iwadate-Horio (1998)

1 10 100 1000 100001E-7

1E-6

1E-5

1E-4

1E-3

h=0

.057

7

1 10 100 1000 100001E-7

1E-6

1E-5

1E-4

1E-3

1 10 100 1000 100001E-7

1E-6

1E-5

1E-4

1E-3

1 10 100 1000 100001E-7

1E-6

1E-5

1E-4

1E-3

No. 7

dobs=373mm

dcalc=667mm

Fexp

Fcoh,rup

da[mm]

No. 6

Fexp

Fcoh,rup

dobs=607mmdcalc=726mm

da[mm]

No. 4

dobs=677mm

dcalc=621mm

Fexp

Fcoh,rup

da[mm]

F[N

]

da[mm]

No. 5

Fexp

Fcoh,rup

dobs=788mmdcalc=723mm

Fig. 13 Agglomerate size determination (PSG:2hr, pre-sieving by 16mesh)

F[N

]

F[N

]

F[N

]

F[N

]

h=1

h=1

hcr

i=0.

0390

h=1

h=1

h=1

hcr

i=0.

0808

hcr

i=0.

152

=hcr

=hcr

=hcr

=hcr

Agglomerate size determination by I-H

model (Takano et al. Powd. Tech.,accepted,2001; Lactose;

PSG:2hrs, presieving by 16 mesh)

Fe

xp

an

d F

co

h,r

up

[N

]

Comparison of model predictions with observed data

d a,

ca

lc [m

]

0E+0

2E-4

4E-4

6E-4

8E-4

1E-3

1.2E-3

1.4E-3

0E+0

2E-4

4E-4

6E-4

8E-4

1E-3

1.2E-3

1.4E-3

Lactose

ZnO

L:E=7:3

L:E=1:1

L:E=3:7

d a,obs [m]

Model (IHM)

works !

Possibility of size control by

surface modification

by

vacuum drying, CH2OH or

NH4OH adsoption

Nishii and Horio (1996)

Me

dia

n d

iam

ete

r [

10

-

6m

]

Absorption time [h]

500

Me

dia

n d

iam

ete

r [

10

-

6m

]

300

400

500

293K,

4kPa

0 3 6 9 12

Me

dia

n d

iam

ete

r [

10

-6m

]

300

400

200

573K,

13.3kPa

0 3 6 9 12 Absorption time

[h]

Absorption time [h]

400

500

600

293K,

4kPa

0 3 6 9 12

Absorption time [h]

300

400

500

Med

ian

dia

mete

r [

10

-6m

]

573K,

13.3kPa

0 3 6 9 12

(a) C2H5OH (b) NH4OH

Mean size of PSG granules from TiO2 (0.27x10-6m) after heat treatment and surface modification

heat treatment:at p<13.3Pa

523K, for 6 hrs

adsorption:

bed= 150x10mm

in a 0.03m3 vacuum

dryer

PSG: charge=0.0333 kg

u0=0.55 m/s RH: 40-

50%

fluidiz.:15 s comp.: 1 s

total cycles=450

adsorption at:

p(adsorbate):

Nishii & Horio (Fluidization VIII, 1996)

Notes: At 573K all

hydroxyl groups

on TiO2 are

eliminated

(Morimoto, et al.,

Bull. Chem. Soc.

JPN, 21, 41(1988).

Highest heat of

immersion at 573K

(Wade &

Hackerman, Adv.

Chem. Ser., 43, 222,

(1964))

No effect: desorbed

during PSG

No effect ??

Applications

Hard metal and Pharmaceutical

Agglomerate 1

Powder 1 Powder 3 Powder 2

Agglomerate 2 Agglomerate 3

feed compositions

powd. dp(WC) WC Co wax*

x10-6m %wt %wt %wt

1 1.5 93.0 7.0 0.5

2 6.0 85.0 15.0 0.5

3 9.0 77.0 23.0 0.5

dp(cobalt)=1.3-1.5x10-6m

*) Tmp(wax)=330K

preparation: 1. grinding 2.5hr 2. vacuum drying PSG: Dt=44mm charge=150g u0=0.548 m/s P(TANK)=0.157 MPa total cylces=64

Hard Metal Application

SEM images of feeds and

product granules

Nishii et al., JJSocPPM(1994)

Application to hard metal industry (Nishii et al., JJSPPM(1994))

Improved strength of sintered

bodies

PSG

method

convent-

ional

method

T

ransvers

e r

uptu

re s

trength

[N

/mm

2]

Co content [wt%] Co content [wt%]

PSG

method

Co-agglomeration

of lactose and ethensamide

O

H

H

HO

O

CH2OH

H

OHH

OHH

OH

H

OHH

OHH

OHH

CH2OH

･H2O

C-NH2

O

OCH2CH3

Lactose Ethenzamide

CH3

O

OH

HN

C

Acetaminophen

Molecular structures

top: PSG granules; second line: surface of agglomerate

(SEM)

Co-agglomeration of lactose

and ethensamide

L : E=1 : 0

500mm

L : E=0 : 1

500mm

L : E=3 : 7

500mm

L : E=1 : 1

500mm

L : E=7 : 3

500mm

10mm

L : E=0 : 1

10mm

L : E=3 : 7

10mm

L : E=1 : 1

10mm

L : E=7 : 3

10mm

L : E=1 : 0

L : E=1 : 0

500mm

L : E=0 : 1

500mm

L : E=3 : 7

500mm

L : E=1 : 1

500mm

L : E=7 : 3

500mm

10mm

L : E=0 : 1

10mm

L : E=3 : 7

10mm

L : E=1 : 1

10mm

L : E=7 : 3

L : E=0 : 1

500mm

L : E=3 : 7

500mm

L : E=1 : 1

500mm

L : E=7 : 3

500mm

10mm

L : E=0 : 1

10mm

L : E=3 : 7

10mm

L : E=1 : 1

10mm

L : E=7 : 3

10mm

L : E=1 : 0

0 20 40 60 80 1000

20

40

60

80

1001000mm

500mm

250mm

Co

nc

en

tra

tio

n o

f E

the

nza

mid

e

in P

rod

uc

t G

ran

ule

s [

%]

Average Mass Concentration of Ethenzamide in Feed [%]

Granule Sample : 10mg

Chemical Uniformity of PSG

granules

UV

absorbance:

300nm

Fra

ctu

re t

en

sile s

tre

ss

[k

N/m

]2

Ethenzamide Content of Mass Charged Powder [%]

0 1 2 3 4 5 60

10

20

30

40

50

60

70

0 30 50 70 100

Ethenzamide

Fracture Tensile Stress of Granules

stage0:>11 m m

stage1:7-11 m m

stage2:4.7-7 m m

stage3:3.3-4.7 m m

stage4:2.1-3.3 m m

stage5:1.1-2.1 m m

stage6:0.65-1.1 m m

stage7:0.43-0.65 m m

Filter:<0.43 m m

air chamber

Cascade Impactor

ejector

pump 28.3L/min

compressor 28.3L/min

throat

differented pressure sensor

1.2mm

2.5L

capsule No.2 HPMC

vacuum

Preliminary test of DPI application of PSG

granules Takano, Nishii & Horio (2000)

Agglomerate size [mm]

Cu

mu

lati

ve

un

der

siz

e[-

]

0 0.2 0.4 0.6 0.8 1 1.2 1.4 0

0.5

1

Ethen 100%

450M 50%

450M 25%

450M 75%

450M 87.5% 450M 81.25%

325M 75%

325M 62.5%

Application of PSG granules

to DPI ?

0 80 160

50

100

Cu

mu

lati

ve

siz

e d

istr

ibu

tio

n [

%]

Primary particle diameter [mm

Lactose(450M) d p = 11.9 m m

Ethenzamide

Lactose (325M) d p =54.7 m m

Ethenzamide (Jet milled) p=1.94mm

p=18.4mm

Size distributions of PSG

granules for a DPI test

(42-32mesh)

0

5

10

15

20

25

30 F

racti

on

[%

] E=100

E/325M=75/25

E/325M=62.5/37.5

E/450M=75/25

E/450M=50/50

E/450M=25/75

Deagglomeration and dispersion

of PSGgranules Takano, Nishii & Horio (2000)

0

5

10

15

20

25

30

35 F

racti

on

[%

] E=100

E/325M=75/25

E/325M=62.5/37.5

E/450M=75/25

E/450M=50/50

E/450M=25/75

Dispersion of PSG granules

by Fujisawa’s E-haler (42-

32mesh)

Concluding remarks

Knowing the nature of both

suspension and suspension-

wall interactions and

governing them to get good

products should be the role

of fluidization engineers.