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Thorvald UllumFluid Mechanics Group

Test & Development

GEA Niro

Modelling the Spray Drying Process

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Process Engineering / GEA Niro2

The Spray Drying Process & CFD

3) Hot air

1) Liquid feed

2) Liquid atomization

4) Particle formation

5) Powder recovery

CFD inputs:

• Air inlet•Spray

•Heat loss

•Gas-particle interaction

CFD outputs:

• Air outlet

•Particle flow (deposits)

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Process Engineering / GEA Niro3

Particle Morphologies

water 

solid core

2. Ranz-Marshall drying model1. Particle morphology examples

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Process Engineering / GEA Niro4

DRYNETICS™: 3 Parts

   M

  o   i  s   t  u  r  e

TimeTime

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DRYNETICS™ Part 1: CCD Video Sequence

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DRYNETICS™ Part 2

   M

  o   i  s   t  u  r  e

TimeTime

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DRYNETICS™ Part 2: Advanced Data Analysis

8

Time

   T  e  m  p  e  r  a   t  u  r  e

   P  o  s   i   t   i  o  n

Size

Stickiness

   T  e  m  p  e  r  a   t  u  r  e

Non-sticky

Sticky

   D  r  y   i  n  g  r  a   t  e

Moisture

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DRYNETICS™ Part 3

   M

  o   i  s   t  u  r  e

TimeTime

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DRYNETICS™ Part 3: CFD Setup – an Example

10

1. Standard models2. DRYNETICS™

• The product is

maltodextrin DE18

with a total feed rateof 96 kg/h.

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DRYNETICS™ Part 3: Air + Particle Streams

1. Gas path l ines

>

2. Tracks of droplets/particles

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DRYNETICS™ Part 3: Evaporation Rate

1. Standard 2. DRYNETICS™

Total: 63.4 kg/hTotal: 65.2 kg/h

 Average particle

moisture at wall

collision is 0.4 wt%

and 9.0 wt%,respectively.

>>

12

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DRYNETICS™ Part 3: Single Particle History

0

0.2

0.4

0.6

0.8

1

   P  a  r   t   i  c   l  e   h  u  m   i   d   i   t  y

   [  -   ]

0 100 200 300 400 5000

20

40

60

80

100

   P  a  r   t   i  c   l  e   t  e  m

  p  e  r  a   t  u  r  e

   [   °   C   ]

Normalized time, t/d02  [s/mm2]

DRYNETICSTM

Standard

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0.2 0.4 0.6 0.8 1 1.2 1.4

DRYNETICS™ Part 3: Rubbery Wall Deposits

2. Physical experiment1. CFD models

Standard:

1.2% rubbery

DRYNETICS™:

70% rubbery

14

[kg/m2h]

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(Very) Large Eddy Simulation

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