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

AFR Route to Success

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 – TemperatureO – 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 regionSIGNIFICANT 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.

Impact of AFR on Output

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.

Impact of AFR on Output

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/ MWCO < 200 ppm at 1.2% O2NOx max to 2.5% O2VF SO3 < 3Avoid cooler/ kiln hood SA flow distortionThese 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 ModifiedBurnout % 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 CaseCoal Burnout (%) 99

EF Burnout % 73Total 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 injectors100% 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 84Calcination % 95 97

Exit O2 % 4.2 3.9Calciner Exit Temperature (C) 865 866

Year Before part Mod After part Mod PercentageClinker 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 OutputOptions 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% TSRGIVES @ 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 1300CSR 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 SizeAv. 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 @ 1secThe SCC fits nicely with the BMH TSS conceptThe 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.

JOHN Over To You

© 2009 Holcim/Switzerland

OH&S in Waste Handling

John JonesJakarta 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

ShukriyaBohoma Istuti Khorb Kun Krup

Cám ón SalamatXie Xie

Kadinchey

max afr and output and relevant oh&s concerns

Technology

burnout afr

impact of afr

use of afr

coprocessing of afr

afr route

waste afr platforms

srf rt

maximum output