Optimal Alternative Fuel Burning Starts with Computer Simulation

Optimal Alternative Fuel Burning Starts With
Computer Simulation
Matthias Mersmann, 22nd August 2018

LOESCHE Symposium Hanoi 2018 22.08.2018
Optimal alternative fuel burning
starts with computer simulation
What happens if…
Why alternative fuels change the production process
What needs to be done to get it right
How to optimize the process for alternative fuel firing
01
04
03
02

Optimal alternative fuel burning starts with computer
simulation
3
What
Happens
if…
▪ … you have signed contracts to get the waste streams to burn alternative
fuels.
▪ … you have set up and invested in the logistics to get the waste to your plant.
▪ … you have worked for years to get the permissions to burn alternative fuel.
▪ … you have invested in new equipment to process the waste to fuel.
▪ … you have invested in pyro-process equipment to burn the alternative fuel.

simulation
4
And
then …
▪ … your kiln production goes down.
▪ … your kiln availability goes down.
▪ … you can burn only half the alternative fuel as you have planned for.
▪ … make sure your plant delivers what your have in mind!
▪ … make sure you master the process!

simulation
5
Make
sure
to…
▪ … understand what is happening during AF combustion.
▪ … transfer the complexity of the process into simulation models.
▪ … optimize the design of equipment & process prior to installation.
▪ … rely on aixergee‘s ‘Real-Physics’ Virtual Reality models.

simulation
6
▪ Transfer of the real plant into virtual reality
▪ ‘Look inside the running process’
▪ Evaluate ALL process parameters:
− Gas flows
− Particle movement
− Temperatures
− Burnout
− Calcination
▪ …
▪ Optimize on the basis of knowledge

8
Do you see the difference?
Noble fuels (primary
fuels) are produced
with the objective be
used as fuels. They
are finely ground and
optimized for being
fired.
Alternative fuels
(secondary fuels) are
made of wasted
material which was
not intended to be
fired initially. They are
processed to be able
to be burned.
They differ in:
▪ Combustion
properties
▪ Pneumatic
properties
Noble(primary)fuels Alternative(secondary)fuels

9
Pneumatic behavior of secondary fuels

10
Combustion of noble fuels
Noble fuels (primary fuels) are produced with the
objective be used as fuels. They are finely ground
and optimized for being fired.
▪ Coal dust ignites spontaneously
▪ Coal dust burns with a short stiff flame

11
Combustion of secondary fuels
Alternative fuels (secondary fuels) are made of
wasted material which was not intended to be fired
initially. They are processed to be able to be burned.
▪ Lumpy particles fall or fly.
▪ It takes long to ignite the AF particles.
▪ It takes long to burn out the AF-particles.

simulation
12
▪ Transfer of the real plant into virtual reality
▪ ‘Look inside the running process’
▪ Evaluate ALL process parameters:
− Gas flows
− Particle movement
− Temperatures
− Burnout
− Calcination
▪ …
▪ Optimize on the basis of knowledge

13
The production process of cement clinker is depending on energy induction at specific locations.
▪ The sintering zone needs a stiff flame of limited length.
▪ The calciner needs a heat release within the riser duct and sufficient burnout without drop out.
Secondary fuels must be prepared appropriately.
▪ Small particles and high specific surface for fast ignition
The plant equipment must be adapted appropriately.
▪ Burners and calciners must allow sufficient retention time for the particles, transport and burn-out.
Alternativefuels flowand burndifferently

15
Kiln burner
Challenge:
▪ Short flight time of particles
▪ Insufficient oxygen availability in
the center of the flame
Solution:
▪ Fine ground RDF (Rocket Mill®)
▪ Specific burner
− Flexiflame ECOPRO
− Satellite burner
RDF
through
central
pipe
RDF
through
satellite
burner

16
Kiln burner simulation features
aixergee ‘Real Physics’ simulation
▪ Full heat transfer (radiation,
convection, conduction)
▪ Fully coupled impulse transfer
▪ Full combustion model
▪ Lumpy & shaped particle flow
▪ Heat transfer into clinker bed
▪ Mineralization of material bed
▪ Ultrasonic flow at burner tip
▪ NOx model
▪ …
RDF flame contribution
Coal flame contribution
RDF trajectories colored by particle size [m] Oxygen concentration profile [m³/m³]

17
Calciner
Challenge:
▪ Keep the lumpy secondary fuel particles in
suspension until they burn out
▪ Drop out fuel is lost and creates problems
in the kiln
Solution:
▪ Find the best injection point
▪ Design the calciner geometry appropriately
Bad fuel suspension: Good fuel suspension:

18
Calciner simulation features
aixergee ‘Real Physics’
simulation
▪ Individual particle
identification
▪ calcination
▪ NOx model
▪ …
RDF (pelletized & partially desagglomerated):
1 Cylinder dense
2 Ball dense
3 Ball med. dense
4 Flat thick dense fluff
5 Flat fluff
6 Flat thin light fluff

19
Calciner simulation features
goodbad
aixergee ‘Real Physics’ Simulation
▪ Individual particle identification
▪ calcination
▪ NOx model
▪ …

21
▪ Cement plant equipment is originally designed for noble fuel combustion.
▪ As alternative fuels differ extremely in flow and combustion behavior, the equipment needs to be adapted.
▪ Adaptation must be based on understanding how the alternative fuel behaves in the process.
▪ Computer simulation is the only method to investigate and predict this behavior.
▪ Design should be based on these findings and not on simple guessing!
▪ aixergee commands on computer models which have proven their realistic prediction in > 250 projects.
Knowingwhat to doinstead of expensive guessing

22
Design process from general understanding to the perfect plant equipment
AF specification
Physical and
chemical
parameters
Simulation of the PRocess
Realistic prediction and
general design of the
equipment
Plantdesign and engineering
Transfer of general design into
steel and machines
Planttechnology
Existing equipment
or new design

23
Example: Calciner modification Aalborg Cement
SLC Calciner with massive problems in
pneumatic transport stability
▪ Cyclical loading and unloading of meal clouds
(mass fluctuation +/- 20%!)
▪ Fall through of meal into the tertiary air duct
▪ Disturbance of combustion and calcination
process
▪ Limitation of AF-firing rate
▪ Occasional CO-peaks indicating AF-firing
overload

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Steeper cone Steeper cone
− Slim shaft
Steeper cone
− Slim shaft
− Elongation
− Mixing chamber
Retrofit proposals

25
Prove of improvement by computer
simulation
▪ Modified calciner
▪ Increase of production rate from 4500
t/d to 4700 t/d
▪ AF-firing 100 % TSR
▪ Much more constant combustion
process
▪ Much less CO as a proof for better
combustion despite higher firing rate
CO generation ‘modified’CO generation ‘As is’

26
LOESCHE can supply everything out of one hand!
Your
alternative fuel
project
your AF
designs your
winning process
provides
tailor-made
engineering &
supply
ensures reliable
partnership
Your success

THANK YOU
for your attention
A company of
LOESCHE Group
Hansaallee 243
D-40549 Düsseldorf
Tel.: +49 211 5353 - 0
Email: loesche@loesche.de

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