Max AFR and Output and Relevant OH&S Concerns

Criteria for Maximising Output and AFR with Relevant
OH&S Requirements
- Tom Lowes
- John Jones -

Cement Production Scenario
 In Asia whilst it generally has not suffered as much as the Western World in
terms of downturn and in many areas the market is sold out and production is
still king, the use of Alternative Fuels and Raw Materials (AFR) by the Cement
Industry is becoming an increasingly important part of a Countries Strategy to
resolve it’s recycling and waste production issues.
 The Customers Produce Waste, the Pre- Processing entity converts the Waste
to AFR which is then used for Co Processing
 The Co Processing of AFR by the Cement Industry has potential bottom line
benefits to its highest cost item, that of Fuel Costs, however there can be
significant issues associated with the use of AFR associated with:-
 loss of output
 appropriate pre and co-processing and increased OH&S requirements
 increased emissions
 Even when the market is not sold out, the Plant needs to perform near to
maximum output when it is producing, due to needs of operational efficiency.
When the market is sold out, any loss in output can make a big difference to
the Plant profit.
 This paper outlines how to maximise output and minimise emission increase
while using AFR together with the OH&S requirements to achieve it

 The loss in output can be significant unless the AFR to be used is well
understood in relation to the Plants operational bottlenecks plus impact on
emissions and clinker quality, which results in significantly less being used
than planned or contracted and a poor return on the investment in pre and
co-processing systems.
 While the use of AFR generally leads to a drop in NOx, its higher volatility,
variability and size compared to prime fuels, can lead to increased CO and
VOCs and SO3 cycles, leading to emission regulation problems and build up
issues leading to Plant stoppages.
 CINAR have the Process Knowledge of the Plant issues associated with the
co-processing of AFR and via its Multi Fuel, Minerals Interactive – CFD,
(which has been customized for the Cement Industry) can resolve any output
or emission issue either at the operational or planning stage.
 Our unique MI CFD allows one to go inside the kiln or calciner, have a look
around, find how it is working and try some solutions before implementing it
on a large scale.
 However the best analytical tools in the world do not help much unless the
basics of the process are well understood and the pre and co-processing
systems as well as the OH&S are not done well.
Using AFR

 Needs
 Avoid excessive build up
 No Significant loss of output
 No increased VOC emission
 Hit NOx targets
 Rules for AFR and Petcoke
 VFSO3 < 2
 HM Carbon < 0.1%
 HM Cl < 1% - 1% by pass per 100mg/kgClk > 300
 Eliminate Kiln and Calciner Stratification
 Need Tom not 3Ts
M – Temperature
O – Oxygen
T – Micro-mixing
 Additional for 500 mg/Nm3
 Tom ++
 i.e. Volatiles and sub stoichiometric RT
Using AFR Effectively
Combustion in a
very narrow
region
SIGNIFICANT
STRATIFICATION
and waste of
space and hence
need big RT

Impact of AFR on Output
 There is much myth and folklore surrounding AFR and its impact on
output, let alone emissions and clinker quality.
 The output losses are always related to current maximum performance in
sold out market – even if it is not – and hence this is normally a fan
limitation. Hence anything that increases the gas volume, due to H2O,
increased fuel consumption or O2 needs can be seen as a drop in output.
 The first major rule to apply is seeking to minimise the impact of AFR on
output is:- %TSR (Thermal Substitution Rate) * Short Terms Thermal
Input Fluctuations = <100%
 For example, if the Plant is at 50% TSR the STTIF (one minute) has to be
<2%. If it was for example 7%, up an extra 1.0 % O2 could be needed to
avoid CO and hence potential 6% loss in output.
 So to go to the higher AFR rates: good pre-processing, handling, firing
systems are needed, plus of course excellent process knowledge.
 The next issues are the impact of H2O, ash, exit temperature and extra O2
have on output. The table on the next shows for a PH/Calciner, where GC-
Giga Cals t-tonnes and fc – fuel consumption.

 The simple one to assess is that impact of H2O and Ash on output with
water being by far the higher. For example a 4000 tpd plant with 50%
of its fuel with 30% water will lose @140 tpd of output or 3.5%.
 Poor AFR control needing an extra 1% O2 will lose 6% output.
 Poor riser or calciner firing will increase the PH exit temperature by
100C increasing fuel consumption by 50 kcals/kg and losing 2.5% in
output – A CURRENT MI-CFD PROJECT.
 The O2 and increased PH temperature can be negated via good process
engineering aided by MI-CFD, however the impact of ash and H2O is
down to the availability of the AFR and various choices as to
preparation, specification and price.

 In addition, with AFR there are many process problems associated with a
longer flame, reducing conditions in the kiln and hot meal due to unburnts
in the hot meal driving the SO3 cycles and build up. They are a function of
the process and the fuels used as well as the level of external help given to
supplement the local process knowledge.
 It is imperative for successful AFR use at a Plant that the choice of AFR
quality is made with reference to the Plant co processing and pyro
capabilities.
 However to get your Pyro Plant AFR one first has to know your Plants Pyro
State and Eliminate Stratification to avoid significant loss is output and
increased VOC/CO emissions.
 While the Calciner performance dominates the AFR TSR potential, the role
of a poor/ good burner cannot be overlooked.

Good Kiln Burner Criteria to Avoid Stratification
Kiln Burners Rules forn 75% TSR
11N/ MW
CO < 200 ppm at
1.2% O2
NOx max to 2.5% O2
VF SO3 < 3
Avoid cooler/ kiln
hood SA flow
distortion
These will allow
unburnt C in hot meal
burnout before the
after calcination zone
and 75% Burner TSR

100 % Calciner TSR
 Impossible many would say without 8 secs RT, many Asian calciners are < 3
secs, so is 100% TSR impossible?
 NO!!! CINAR has modified a 2 sec RT for £1.5m that can get 100% TSR
 Look at the car development
 1 litre engines now produce the power of 10 litres 50 years ago
 How has the development been done?
 Via well customised CFD programmes for Engine combustion for both
diesel and gasoline
 A customised CFD programme – MI-CFD – can do the same for a small
calciner
 SO Tune the Engine, give it a TOM
 What is the Engine
 Coal and AFR injection, TA , meal and gas riser.
 The micro mixing or O2 and fuels need to be optimised with respect to
combustion and heat transfer to the meal.
 The is little point in adding volume at the cold end if the engine is
poorly tuned.

100 % Calciner TSR
 CINAR did initially work for this calciner plant to overcome problems of poor coal
burnout and calcination and very bad build up.
 This is shown on the next 3 slides, how a low cost modification to the TA inlets
enabled them to overcome the problem and get to @ 70% calciner TSR with an
Engineered Fuel (SRF), however the Plant Manager wanted to get to 100%.
 As the calciner has only 2 secs RT this proved to be difficult for them, due to CO,
less of output and elevated PH outlet temperature and we were asked again to
help.
 From simulations of the current operations it was identified that:-
 The SRF was being quenched too fast to get a good burnout and its path was going
to the lower O2 regions in the calciner and only burning out to 73%.
 Simulations of the SRF and coal injection points, plus meal splits and a venturi, a
series of recommendations were made to get potential to 100% TSR.

Oxygen Mass Fraction [-]
Original 2
TA inlets,
very poor
mixing with
the coal
Modified
TA to a
Horseshoe
Original Modified
Burnout % 70 93
Calcination % 70 90

Oxygen Profiles/ Fuel Trajectories
Coal / O2
O2 [m/ m]
EF / O2
The EF releases
if volatiles
fast, but is then
quenched too
fast by the meal
and then travels
in a low O2
region which
makes the
burnout poor
Near the walls of
there are oxygen
rich areas where
available oxygen
would enhance
the burnout
Case Base Case
Coal Burnout (%) 99
EF Burnout % 73
Total Burnout % 81
Calcination 95
70% TSR increased
CO and kcals/kg and
lower output

EF particles in O2 - Meal particles in Temperature
70%
Profuel Axial Sleeve of
EF injectors
100%
Profuel
O2
T (C)
Adding a
lower meal
inlet
Currently
being
implemented

Implementation and Feedback
 Based on the MI-CFD simulations, modifications were proposed to the SRF
burners, meal split and the installation of the customized venturi design
not only to stop the SRF drop out but to improve the mixing of the O2 with
the EF. The predicted change is below:
 So the burners have been modified and part of the Venturi has been
installed, with the change below from the Plant info, which shows already
85% TSR , more output, less CO and better kcals/kg, with a potential
savings of > €1mpa and a pay back on the MI-CFD of 2weeks.
•
Case 70/30 100%
Coal Burnout (%) 99 -
Eng. Fuel Burnout % 73 84
Calcination % 95 97
Exit O2 % 4.2 3.9
Calciner Exit Temperature (C) 865 866
Year Before part Mod After part Mod Percentage
Clinker tpd 2788 2838 2%
EF firing rate tph 6.8 8.2 21%
PH Exit Temperature 431 416 4%
ID fan O2 ppm 7.5 6.6 14%
ID Fan CO ppm 1110 930 19%
Fuel Comsumption kcals/kg 936 896 5%

Calciner Modification for AFR and Output
Options
 Zero Capex – Process evaluation MI-CFD – calciner burner, AFR injection
and meal location optimised – 100 % TSR possible with specific AFR for
RTs < 3 secs
 Low Capex - < $2m US – as above but with TA optimised 100% TSR possible
for a wider range of AFRs
 Modest CAPEX < $5m US – SCC recent PMTech/ CINAR develop for most
AFRs up to 75mms and 100% TSR
GIVES @ 6 secs AFR RT with a gas RT volume of 1 sec RT
and fits with the new BMH TSS Concept

Generic Calciner for 100% TSR and Low NOx
CINAR customised HOT REBURN
– 0.15 secs at 1300C
SR volatile < 0.9
Non coating refractory (SiC)
plus blasters
Customised Venturi for AFR
Further reburn and stating
section to allow HCN -> N2
with up to 50% meal quench,
at least 0.5 secs
Opposed TA inlets
or horseshoe to
enhance mixing
and avoid
stratifications
Enhanced mixing
and combustion
region – hot spot –
controlled by rest
of meal
2.5 secs RT above TA, for
calcination and burnout
AFR and Coal
burners design
and location
customised as a
function of
specification

Separate Combustion Chamber(SCC) Concept
SCC Skewed to both
Vertical and horizontal by
@ 10deg, to achieved >
SRF RT

SRF Residence Time (sec.) Fn Size
Av. RT: 2 s
5 mm 10mm 20mm 30mm 50 mm
Av. RT: 4 s
Av. RT: 5 s
Av. RT: 10 s
Av. RT: 12 s

SRF Burnout (%)
Burnout %
Average SRF BO at
SCC exit: 96%
The bigger the SRF the
longer the RT and hence a
good Burnout is assured,
even with only a gas RT of
@ 1sec
The SCC fits nicely with the
BMH TSS concept
The SCC BURNS ALL
and the
TYRANNOSAURUS EATS
ALL

Calciner
optimisation
 LOI compared to
Temperature
 CO < 500 ppm at 2.5%
O2
 PH Temperature 350 - 4
stage, 325 – stage, 290 –
6 stage
 MI-CFD - O2
stratification
 Burners
 Meal
 TA
 SCC
Calciner Rules for 100% TSR

All well and good, but major issues are
associated with waste/ AFR platforms and
OH&S before even using AFR at a Kiln.

© 2009 Holcim/Switzerland
OH&S in Waste Handling
John Jones
Jakarta Cemtech June 2013

Geo means “earth” in Greek, while Cycle calls to mind the cycle of
life. “Geocycle” refers to our ability to convert waste into a safe,
useable resource
Geocycle Asia Network
Geocycle is the waste management brand of Holcim, one of the world’s
leading suppliers of construction materials

26
Waste Generation From Society

© 2008 Holcim/Switzerland,
Waste Generation From Industry

What Happens If We Get It Wrong?

Holcim OH&S Cardinal Rules
• 1. Do not override or interfere with any safety provision
(nor let override or interfere anybody else, regardless of their
seniority to yourself)
• 2. Personal Protective Equipment (PPE) rules, applicable
to a given task, must be adhered to at all times
• 3. Isolation and Lock Out Procedures must always be
followed
• 4. No person may work if under the influence of alcohol
or drugs
• 5. All injuries & incidents must be reported

Geocycle Introduction to OH&S
• OH&S related actions are implemented at all steps of Geocycle
business processes
• Know the processes, identify all possible risks at all steps of the
customer service chain
• Risk registers for all possible risks (safety, health,
environmental, quality, legal and business)
• Be aware of all local legal requirements: regulatory, permits etc.
• Corporate requirements in company documentation
• At all times our approach is: Hazard Identification, Risk
Assessment and Control (HIRAC)

Information Gathering
• Customer enquiry
• Customer site visit
• Data gathering: industry type, how was material generated,
volumes, frequency, package type
• Check all package types: drums, IBCs, containers, tins, boxes,
pallets, tanks, bags etc
• Collect samples, safety data sheets, digital photos, reports etc
• Transport company visit and qualification
• Labour agency visit and qualification

Waste Sampling

Waste Sample Analysis
• Laboratory chemical
analysis
• Laboratory physical
analysis
• Chemical
compatibility test
• Followed up by team based multi-disciplinary risk assessment

Risk Assessment For New Waste Streams
• Gather all analysis results, paperwork, digital photos etc for
discussion
• Need to address the issues of: OH&S, operating licenses, plant
operations, kiln operations, handling, commercial, logistics,
laboratory, technical and process
• Team based multi-disciplinary acceptance process
• Don’t say “no”, instead ask “how can we do this safely?”

OH&S Risk Rankings (Consequence)
Consequence
RANKING DESCRIPTION OF CLASSIFICATION
1 Illness, injury requiring first-aid or no treatment
2 Medical (doctor) treatment
3 Single serious (hospitalization) injury
4 Single death or major permanent disablement
5 Multiple deaths
Consequence can be rated from a ranking of 1 (considered
minor) to 5 (catastrophic), see corporate procedure

OH&S Risk Rankings (Likelihood)
Likelihood
RANKING DESCRIPTION OF CLASSIFICATION
A Expected many times per year
B Expected about once per year
C Expected between once every year and once every 10 years
D Expected between once every 10 years and once every 100
years (possibly once or twice in the life of a site/plant)
E Expected between once every 100 years and once every 1000
years (not expected to occur in the life of a site/plant)
Likelihood ranks from A (considered certain) to E (improbable)
with a range of values in between as shown below. IMPORTANT:
Typically the likelihood scale is logarithmic with each succeeding
level being a factor of ten times more or less likely than the
adjacent level.

OH&S Risk Rankings
Risks are ranked from low (possibly acceptable) to extreme. The
risk ranking is used to provide a prioritization of risks and
therefore the basis for developing risk management plans and
allocating valuable risk management resources
Consequence 1 2 3 4 5
Likelihood
A H H E E E
B M H H E E
C L M H E E
D L L M H E
E L L M H H
• E = Extreme risk - immediate top management action required
• H = High risk - senior management attention required quickly
• M = Moderate risk - management responsibility must be specified
• L = Low risk - manage by routine procedures; eg. Work
Instructions

OH&S: Hierarchy of Controls
The hierarchy of controls is as follows:
• Eliminate the hazard
• Substitute with a lesser hazard
• Use Engineering controls to reduce hazard
• Administrative controls such as workplace procedures
• Personal Protective Equipment
• In many cases, it will be necessary to use more than one control
method. Back-up controls (such as personal protective
equipment and administrative controls) should only be used as
a support to other control measures

Putting The Required Controls In Place
• Once identified they need to be put in place

OH&S: Progress in Geocycle Asia

Implementation of Controls – Geocycle Vietnam

OH&S: Operational Improvements
From this to this

Investment in Operations: Geocycle Thailand

What Happens If We Get It Right?
http://www.sundaytimes.lk/110403/BusinessTimes/bt09.html

Thank You
Terima Kasih
Shukriya
Bohoma Istuti
Khorb Kun Krup
Cám ón
Salamat
Xie Xie
Kadinchey

Max AFR and Output and Relevant OH&S Concerns

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