Odudimu Certification Scenerio

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Presentation on kiln and Mill Incidents

June 2012

CEMENT

WAPCO Nigeria Ewekoro 1

Name: ODUDIMU, OLUTAYO OLUGBENGA

Plant: EWEKORO 1

Function: CCRO

Experience: 7 yearsBackground: MECHANICAL ENGINEERING

CRO Certification session


2/50

Date 2

INTRODUCTION

When operating the best designed and most stable plant, theoperator may face an emergency situation once in a while which

requires immediate and drastic action. Quick and appropriate

reaction is extremely important to prevent serious damage to the

kiln and related equipment. In such cases, the Central Control

Room Operator must ignore the normal criteria for stable operation

and concentrate on getting full control of the immediate,

dangerous situation. Most Important in such a situation is of

course that the operator tries to keep his / her head cool.


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Date 3

CONTENTS

Page

Kiln Scenario1: Clinker Conveyor Stoppage 4 - 12

Kiln Scenario 2: Cold Kiln 13 22

Kiln Scenario 3: Burning Zone Ring Fallout 23 - 31

Mill Scenario1: Limestone Failure / Pile Change over 32 - 37

Mill Scenario 2: VRM fill up 38 - 43

Mill Scenario 3: Mill Feed Belt Stopped 44 - 49


4/50

Date 4

KILN SCENERIO 1:Clinker Conveyor Stoppage


5/50

Date 5

Clinker Conveyor Stoppage

On the 22nd December 2011 at 5:30pm, Methods Inspector on

routine inspection noticed three (3) bad rollers on the apron clinkerconveyor and immediately activated the emergency switch to

prevent damage to the conveyor.

The sudden stoppage led to the stoppage of cooler breaker

hammer and cooler drives which eventually force down the kiln

drive to minimum speed (0.36rpm)

One very bad roller was replaced within four minutes, clinker

transport conveyor and cooler drives ran for about 10 minutes to

reduce the materials in the cooler and repositioning for the

remaining two bad rollers, which was completed after another 5

minutes.

CONSEQUENCE

Thermal damage to the cooler components.



6/50

Date 6


Incident Date: 22nd December 2011

Time : 5:30pm to 5:50pm

Shift: Day Shift

BEFORE THE INCIDENT DURING THE INCIDENT

180 Kiln Feed in tph 120

Main Burner Fuel in Nm3/hr 4024 Main Burner Fuel in Nm3/hr 3610

Calciner Fuel in Nm3/hr 6470 Calciner Fuel in Nm3/hr 4176

ID fan damper in % 45 ID fan damper in % 35

Kiln Speed in rpm 3.4 Kiln Speed in rpm 0.36

Cooler Speed in stroke/min 15.1 Cooler Speed in stroke/min 0

Preheater Exit

Temperature in degree 360 Preheater Exit Temperature 405

Cyclone 4 Temperature 845 Cyclone 4 Temperature 850


7/50Date 7

Clinker Conveyor StoppageActions taken Significance

Immediate Selection of kiln / Cooler built in

interlocking as in EWE-PRD-K-043

To increase the interlocking time before stopping the kiln

when cooler is not running

kiln feed reduced gradually from 180tph to 120

tph

To prevent poor heat exchange between gas and

material and unstable burning zone as a result of high

volume loading in the kiln. To prevent material over -

spilling from the backend.

Main burner fuel, calciner fuel, ID fan draft were

reduced stepwise

To prevent overheating of the burning zone andmaintain constant free lime, maintain constant

calcination to prevent shift in the burning zone andmaintain constant oxygen and in excess at the kilnbackend and at tower exit.

Continuous shooting of cooler shut blasters / air

cannons

To move the hot materials at the CIS section of thecooler forward and prevent snowman formation in thecooler

Missing bolts on the conveyor replaced by

Mechanical crew

To prevent deformation of the apron conveyor

Clinker Conveyor, clinker breaker hammer andcooler drives stated back as in EWE-PRD-K-029

Kiln speed gradually increased to maintain kiln

speed feed ratio

To maintain constant volume loading

Kiln ramp up starts after stability have beenattained using SOP for ramp up i.e. EWE-PRD-K-032

To optimize the operation.


8/50Date 8

Clinker Conveyor Stoppage (Event Trend from ECS)

Kiln Speed

Left Grate

Center Grate

Right Grate

Pressure after ID fan

Hood Pressure

Kiln Feed

Calciner Burner Fuel

Main Burner Fuel

Compartment 1 PressureID fan Damper


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Preheater Outlet Temp

ID fan Damper

Kiln Torque

Cooler Speed

Kiln Feed Flow

Apron Conveyor Current

Kiln Speed Burning Zone Temp

Kiln Hood Temp

Clinker Conveyor Stoppage (Event trend from IP 21)


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ID fan Damper

Cyclone 4 temp

Kiln Feed

ain Burner Gas Flow

Calciner Burner Gas Flow


Compartment 1 Pres.


Clinker Conveyor Stoppage (Event trend from IP 21)


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Clinker Conveyor Stoppage (Event trend from IP 21)Burning Zone Temp

Kiln Speed

Calciner gas Flow

ID fan Damper

ID fan outlet Pressure

Kiln Feed flow

Cooler Centre Grate


Cooler Left & Right Grate

Compartment 1 Pres.

Preheater Exit Temp

Kiln Inlet temperature

Compartment 2 Pres.

Kiln Hood Temp.

Cyclone 4 Temperature


12/50Date 12

Learning points

Kiln Coach Comment and Recommendation

The operator needs to be highly composed, take fast and good

decisions and be attentive to useful information to be able to tackleany emergency emanating from plant operation

.

Good action to save the kiln. The CRO must be well informed of the

plant SOP and always at alert to manage the emergency condition.

Iduh Lucky (Kiln Coach)


13/50Date 13

KILN SCENERIO 2: COLD KILN


14/50Date 14

On the 29th May 2012 between 8:10am and 9:20am, there was

increase in the Carbon II Oxide (CO) level at the Preheater Exit ofthe kiln from 0.0 % to 0.05% (500ppm) leading to slight cooling of

the burning zone.

During the first appearance of the CO at the preheater exit, the

Induced Draft fan damper was opened gradually to vent the

system. Then, the feed and the speed were later reduced.

As the material got to the burning zone, there was sharp drop in

the in the secondary air temperature, burning zone temperature

and cooler compartment 1 undergrate pressure.

KILN SCENERIO 2:COLD KILN


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INDICATORS Appearance of CO at the preheater exit analyser

Decrease in the burning zone

Decrease in the NOx level

Decrease in burning zone temperature and secondary airtemperature.

CONSEQUENCES AND DANGER

The presence of CO results from an incomplete combustion with therelease of unburned particles falling into the material load. Theconsequences are:

Local area of reducing condition

Kiln feed end chamber build up

Formation of sulphate ring

Easier SO3 Volatilization

Higher heat consumption.Date 15



16/50Date 16

KILN SCENERIO : COLD KILN

Incident Date: 29th May 2012

Time : 8:20am - 9:00am

Shift: Day Shift of 29th May 2012


kiln Speed in tph 3.6 kiln Speed 3.3

Kiln Feed in rpm 200 Kiln Feed 185

Cyclone 4 temperature 846 Cyclone 4 temperature 865ID fan damper 81 ID fan damper 85

Calciner Fuel 7621 Calciner Fuel 7539

Main Burner Fuel 4305 Main Burner Fuel 4355

Burning Zone Temperature 1421 Burning Zone Temperature 1178

Preheater Exit CO level in % 0 Preheater Exit CO level in % 0.05

Preheater Exit Oxygen level in % 3.9Preheater Exit Oxygen level in% 4.1

Preheater Exit NOx level in ppm 348 Preheater Exit NOx level in ppm 228

Preheater Exit Temperature 350 Preheater Exit Temperature 354

Compartment 1 Pressure 63 Compartment 1 Pressure 61

Cooler Speed 21.1 Cooler Speed 15.5

Kiln SHC 776.81 Kiln SHC 846.25


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Quality Parameter on 29th May 2012

Date 17

Kiln Feed

TIME LSF % SR % AR % C3SSO3/ALKALIS %

RES(100um)

RES(200um)

8am 100.39 2.64 1.35 75.8 0.52 11.01 2.16

10am

12am 99.37 2.71 1.34 74.02 0.5 11.56 2.16

2am

Clinker

TIME fCao % LSF % LW C3S C2S C3A SO3

8am 2.97 91.14 1.28 44.46 32.66 6.41 0.13

10am 4.42 101.19 1.26 58.66 14.89 6.01 0.14

12am 2.74 98.4 1.31 61.24 15.51 6.18 0.12

2am 2.46 99.45 1.29 59.97 12.06 5.63 0.11


18/50Date 18

COLD KILNActions taken Significance

ID fan damper increased gradually from 80% to

86% as in EWE-PRD-K-023E

To improve the efficiency of combustion and clear the

CO formation in the kiln

Kiln Feed and Kiln Speed reduced gradually

from 200tph and 3.6 rpm to 185 tph and 3.3 rpm

respectively.

The reduction in speed was to increase the material

retention time in the kiln and to raise the burning zone

temperature and reduction in the feed was to reduce the

kiln volume loading

Reduced Induced draft fan damper opening To maintain backend temperature, improved the burning

zone temperature .

Slight Increase in main burner fuel rate To raise the burning zone temperature and lowerpercentage oxygen at the inlet

Reduce Cooler grate speed To maximize and regularize heat recuperation andmaintain constant cooler clinker bed depth


Clinker diverted to the clinker dump Not to pollute the clinker in the silo

Kiln ramp up starts after the kiln had heated up

using SOP for ramp up as in EWE-PRD-K- 032


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Date 19

Burning zone Temp

Compartment 1 Pres

Cooler Speed

Preheater Exit Temp

Cyclone 4 Temp

Preheater Oxygen

Preheater CO

Main Burner Fuel

Calciner Fuel

ID fan Damper

Kiln Speed

Kiln Feed

Kiln SHC



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Date 20


ID fan damper

Kiln inlet Oxygen

Preheater O2

Preheater COPreheater NOx

Kiln Inlet Temp

Kiln Inlet CO

Kiln Inlet NOx

Kiln TorqueKiln Load

Burning Zone Temp

Kiln HoodTemp



21/50

Date 21

Learning points

CO presence at the preheater if not properly handled can lead to kiln flush

and lower production rate.

To always maintain stable operating parameter in order to prevent shift in

burning zone.

To always stabilize cooler operation to prevent fluctuation in secondary air(kiln hood) temperature and tertiary air temperature

The operator needs to be highly composed, take fast and good decisions

and be attentive to useful information to be able to tackle any emergency

emanating from plant operation


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Date 22



23/50

Date 23

KILN SCENERIO 3: BURNING ZONE RING

FALLOUT


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Date 24

Burning Zone Ring Fallout

On the 17th June 2012 between 8:00pm and 9:00pm, Burning

Zone ring break loose in the kiln leading to slight cooling of theburning zone.

Before the incident, the speed was on maximum speed 3.6 rpm to

allow for the regular flow of material into the cooler as a result of

ring impeding the flow of feed (material) in the kiln. This was done

to achieving high cooler bed for optimal heat recuperation.

As the coating drops, the kiln speed, kiln feed and ID fan damper

were reduced for higher retention time in the kiln, and cooler

speed reduced to maintain constant cooler bed depth for optimal

heat recuperation while the main burner fuel was slightly

increased.

Further reduction in kiln feed was later done to raise the burning

zone temperature.

KILN SCENERIO 3:BURNING ZONE RING FALLOUT


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INDICATORS Sudden change in the kiln drive amperage. There is a steep

increase in the kiln power followed by gradual drop in kiln power.

As power drops, kiln exit NOx and burning zone temperaturedecreases.

Change in shell temperature on the kiln shell temperature scanner

Large lumps observed at the burning zone after few minutes

CONSEQUENCES AND DANGER

Thermal damage to the cooler components.

Overloading of the cooler with unburned feed

Red hot clinker will leave the cooler damaging the upstream equipment

Large pieces may jam the cooler hammer crusher

Large quantities of material in burning zone resulting in cooling of burningzone,

Damage to the cooler drive and grates Date 25

KILN SCENERIO 3:BURNING ZONE RING FALLOUT


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Date 26

BURNING ZONE RING FALLOUT

Incident Date: 17th June 2012

Time : 8pm - 9:00pm

Shift: Night Shift of 17th June 2012


Kiln Feed in tph 150 Kiln Feed in tph 135

Main Burner Fuel in Nm3/hr 3895 Main Burner Fuel in Nm3/hr 4015

Calciner Fuel in Nm3/hr 6345 Calciner Fuel in Nm3/hr 5811

ID fan damper in % 75 ID fan damper in % 50

Kiln Speed in rpm 3.6 Kiln Speed in rpm 3.0

Cooler Speed in stroke/min 18 Cooler Speed in stroke/min 14.2

Preheater Exit Temperature 358 Preheater Exit Temperaure 360

Cyclone 4 Temperature 840 Cyclone 4 Temperature 860


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Date 27

Burning Zone Ring FalloutActions taken Significance

kiln speed was first reduced and later kiln feedas in EWE-PRD-K-044 The reduction in speed was to increase the materialretention time in the kiln and to raise the burning zone

temperature and reduction in the feed was to reduce

the kiln volume loading

Reduced Induced draft fan damper opening To maintain backend temperature, improved the

burning zone temperature .

Slight Increase in main burner fuel rate To raise the burning zone temperature and lowerpercentage oxygen at the inlet


Patroller called to carried out inspection toensure that there was no damage toequipment and accident on personnel

Kiln ramp up starts after the kiln had heated

up using SOP for ramp up as in EWE-PRD-K-032

B i Z Ri F ll


28/50

Date 28


Kiln Speed

Main burner gas Flow

Kiln Feed

Preheater Analyser NOx

Kiln Torque

ID fan damper

Calciner gas flow

Burning Zone Temp

Preheater Outlet Temp

Cyclone 4 Temp

B i Z Ri F ll t


29/50

Date 29


Kiln inlet NOx

Burning Zone Temp

Preheater Exit Oxygen

Torque

Kiln Feed

Hood Pressure Temp

Cyclone 4 Temp

Calciner Burner Fuel

Main Burner Fuel

Compartment 1 Pressure

Kiln Speed

Central Grate Speed.

Kiln Load

ID fan damper


30/50

Date 30

Learning points

To always observe burning zone temperature and comparing with it NOxmeasurement, kiln torque and kiln load.

To follow up with laboratory in the examination of the chemistry of the kiln

feed including dust return quantity for possible elimination of ring

formation

To always maintain stable operating parameter in order to prevent shift in

burning zone.

To always stabilize cooler operation to prevent fluctuation in secondary air

(kiln hood) temperature.


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Date 31


Good reaction except for the feed, although, it was due to

the ring. But let us thereafter maintain constant feed to

speed ratio


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Date 32

MILL SCENERIO 1: Limestone failure /Chute Blockage

MILL SCENERIO 1 Limestone fail re /


33/50

Date 33

INTRODUCTION

On the 23th December 2011 at 9:30pm, the limestone reclaimer

went on manual trip. The patroller was called to investigate the

cause of the manual trip and make the reclaimer available for mill

operation. It was discovered that there was chute blockage in

reclaimer discharge chute to BC04 belt conveyor.

The de - blocking of the chute was supervised by the Patroller

while other operational controls to prevent incident stoppage on

the mill was carried out at Central Control Room.

CONSEQUENCE

The consequence of feed failure to the mill is excessivevibration which may damage the internal components and the

roller rocker arms.


MILL SCENERIO 1 Limestone failure /


34/50

Date 34


Incident Date: 23rd December 2011

Time : 9:35pm to 10:05pm

Shift: Night Shift


Hot Air damper in % 100 Hot Air damper in % 0

Recirculation damper in % 28.6 Recirculation damper in % 96

Raw feed to the mill in Tph 280 Raw feed to the mill in Tph 0

Mill fan Power in Kilowatt 3153 Mill fan Power in Kilowatt 2842

Mill motor Powerin Kilowatt 1536 Mill motor Powerin Kilowatt 110

Mill fan damper in % 58.4 Mill fan damper in % 38.9


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Date 35

Limestone Failure/ Chute Blockage

Actions taken Significance

Raised the grinding roller as in EWE

PRD

K - 017

To prevent mill vibration as a result of metal to metalcontact between the mill table and the grinding roller

Stop hot gas generator , VRM hot air damper

closed

To prevent overheating of the upstream mill equipment

and damage to the separator bearing and mill fan

impeller and bearing.

Open the mill recirculation damper and slightly

reduced the mill fan damper.

To maintain stable sensible / latent heat in the mill in

preparation for mill start up.

Patroller called to carried out inspection and to

de-block the chute and ensuring that there is

no damage to equipment and accident on

personnel

Grinding Commences and operation stabilized

minutes later as in EWE-PRD-K-006

Limestone Failure / Chute Blockage


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Date 36

Limestone Failure / Chute Blockage

Mill Motor power

Mill Differential PressureLimestone Hopper Level

Fresh feed to VRM

Mill Vibration Cyclone Differential Pressure

Mill Fan Power

Hot air damper positionRecirculation damper

ot Gas Generator gas flowMill Outlet Temp


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Date 37

Learning points

The operator needs to be highly attentive to be able to tackle any

emergency emanating from plant operation



38/50

Date 38

MILL SCENERIO 2: MILL FILLED UP


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Date 39

MILL SCENERIO 2: MILL FILLED UP

Incident Date: 24th December 2011

Time : 9:30pm to 9:50 pm

Shift: Night Shift


Mill differential Pressure in mbar 90 Mill differential Pressure in mbar 121.8

Feed to the mill in tph 286 Feed to the mill in tph 310

Raw mill outlet Temp. in degree 72.3 Raw mill outlet Temp. in degree 63.5

Mill vibration in mm/s 7.9 Mill vibration in mm/s 6.4

Mill motor power in kilowatt 1537 Mill motor power in kilowatt 2221

Mill Product Elevator Current in % 52 Mill Product Elevator Current in % 56

Cyclone differential Pressure in mbar 6.9 Cyclone differential Pressure in mbar 5.3

Hydraulic Grinding Pressure in barab 860 Hydraulic Grinding Pressure in barab 920


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Date 40

Mill (VRM) Filled Up

OBSERVATIONS

Increase in mill differential pressure

Increase in VRM mill active power

Decrease in cyclone differential pressure and mill airflow

Decrease in mill outlet temperature (R1M01N5)

Increase in mill reject elevator current (R1J05)

Increase in the mill product elevator current (W1A10)



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Date 41


Mill Feed Mill Outlet TempMill Differential Pressure

Mill Motor PowerMill VibrationMill Inlet Temperature

Grinding Pressure

Mill Fan Power

VRM reject elevator Current

Mill Product Elevator Current

Mill (VRM) Fill d U


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Date 42



Grinding roller pressure increased from 860barabs to 920 barabs as in EWE-PRD-K-018

To increase grinding efficiency of the material.

Feed to the mill changed from automatic mode

to manual mode and the feed decreased by 20

tph

To reduced the material coming into the mill.

Mill fan damper opening increased from 52 %

to 62 % with increase in the heat input to the

mill

To reduce VRM internal circulation and lift the material insuspension

Operation later stabilized and feed to the mill

changed from manual mode to automatic

mode.


43/50

Date 43

Learning points

Reclaiming operation to be stabilized to prevent fluctuation in mill

operation.

The operator needs to be highly composed, take fast and good

decisions and be attentive to useful information to be able to tackle

any emergency emanating from plant operation



44/50

Date 44

MILL SCENERIO 3: MILL FEED BELT STOPPED



45/50

Date 45

Mill Feed Belt R1J01 Stopped INTRODUCTION

On the 24th April 2012 at 6:00am the mill feed belt conveyor

R1J01 went on manual trip as a result of limestone that activated

the emergency rope leading to the sudden failure of feed into the

mill.

The Separator speed was quickly increased and mill fan damper

lowered to allow materials in suspension to drop on the mill table

since the roller response time when raised was about 90 seconds

which can cause excessive vibration when roller was not fully lifted

up. Also, the heat input into the mill was gradually reduced. The

Patroller called to investigate the cause of the manual trip.

CONSEQUENCE

The consequence of feed failure to the mill is excessivevibration which may damage the internal components and theroller rocker arms.



46/50

Date 46


Incident Date: 24th April 2012

Time : 6:00am to 6:05 am

Shift: Night Shift


Mill Differential Pressure inmbar 103.4

Mill Differential Pressure inmbar 66.7

Feed to the mill in tph 358 Feed to the mill in tph 0

Mill outlet temperature indegree 62

Mill outlet temperature indegree 106.4

Mill motor power in kilowatt 1848 Mill motor power in kilowatt 123

Separator Speed in % 73.4 Separator Speed in % 92.6Mill fan damper in % 68 Mill fan damper in % 46.8

Reject Elevator Current in % 42.9 Reject Elevator Current in % 40.2

Hot Air damper position in % 100 Hot Air damper position in % 0

Mill Vibration in mm/s 6.7 Mill Vibration in mm/s 0.9

Recirculation damper in % 0 Recirculation damper in % 95

MILL FEED BELT STOPPED


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Date 47

Raw feed to the Mill

Recirculation damper

Separator Speed

Hot air damper to mill

Mill fan damper

Raw Mill Act Power

Mill Outlet temp Mill Vibration

Mill Differential Press.

Raw mill inlet temp

Cyclone Differential Press.

Grinding Pressure

VRM reject Elevator


Mill Feed Belt R1J01 Stopped


48/50

Date 48

Mill Feed Belt R1J01 Stopped


Grinding roller automatically raised, though the

response time was low as in EWE PRD K

- 017

Separator speed increased from 73.4 % to

92.6% while the Mill fan damper opening

reduced from 68 % to 48 % with reduction in

the heat input to the mill

To prevent mill vibration as a result of metal to metalcontact between the mill table and the grinding rollerand to reduce VRM internal circulation and lift thematerial in suspension

Stop hot gas generator , VRM hot air damper

closed

To prevent overheating of the upstream mill equipment

and damage to the separator bearing and mill fan

impeller and bearing.

Open the mill recirculation damper To maintain recirculate the heat mill in preparation formill start up, and to prevent turbulence in the kiln

Patroller called to carried out inspection to

ensure that there was no damage to equipment

and accident on personnel

Mill feed and other upstream conveyor started

back

Grinding Commences and operation stabilizedminutes later.


49/50

Date 49

Learning points

The operator needs to be highly attentive to be able to tackle any

emergency emanating from plant operation.



50/50

Thank you

Engr. ODUDIMU Olutayo Olugbenga

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Odudimu Certification Scenerio