ball mill inspection procedure

Ball mill inspection procedure

Ball Ball millmill inspectioninspection procedureprocedureGeneralGeneral

Material Material samplingsampling

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Longitudinal Longitudinal samplingsampling

Filling degreeFilling degree

Material levelMaterial level

Internals Internals conditioncondition

Ball chargeBall charge

TrompcurveTrompcurvepp

VentilationVentilation

WeighfeederWeighfeeder

InstrumentInstrument

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I.E.E.E West CoastI.E.E.E West CoastConference 2009Conference 20098th 8th 9th 9th OctoberOctober

NavigationNavigation

Control loopControl loop

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Tim NowackTim NowackVictorvilleVictorville/ CA/ CAU.S.AU.S.A

The Green The Green TreeTreeConventionConvention CenterCenter

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Christian Pfeiffer Maschinenfabrik GmbH

Senior Process EngineerSenior Process Engineer


General:

GeneralGeneral


The process engineer should be the doctor of the system




doctor of the system.

The doctor is required for:



TrompcurveTrompcurve

1) implementation of Health checks Regular action

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2) urgent investigations of actual process problems Non-regular action




This presentation focuses on the regular Health check procedure.

VictorvilleVictorville/ CA/ CAU.S.AU.S.A



General:

GeneralGeneral


The Health checksconsist of standard measurements on a frequent basis

Type of measurement: 12 months scheduleLongitudinal Longitudinal samplingsampling



Type of measurement: 12 months scheduleCircuit mat. granulometry Q

Mill longitudinal sieving Q Q Q Q

Ball charge filling degree Q Q Q QInternals Internals conditioncondition



Ball charge filling degree Q Q Q Q

Mill material level Q Q Q Q

Mill internal conditions Q Q Q Q

Ball charge sampling QppVentilationVentilation



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Ball charge sampling Q

Separator Tromp curve Q

Separator ventilation Q

Mill til ti Q



Control loopControl loop Mill ventilation Q

Weigh feeder calibration Q

Instrument verification Q Q Q QVictorvilleVictorville/ CA/ CAU.S.AU.S.A

The Green The Green TreeTreeConventionConvention CenterCenter Main annual audit

Control loop verification Q


General:

GeneralGeneral


Healths checks are important in order to:




build up a knowledge and data base about the system performance

record the data and display them in trends for fastInternals Internals conditioncondition



record the data and display them in trends for fast and easy diagnostic of problems

The main ad antageppVentilationVentilation



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The main advantage:

Knowledge basis allows to investigate the root



Control loopControl loop cause of problems and to avoid problems by early reaction based on the trend results.




General:

GeneralGeneral


For each measurement make sure you have:




design data of the machines/equipment available.

constant/stable operation condition for at least 2 hours.




recorded the actual operation data like:

Production rate [t/h], Product type, composition [M-%]

A t l d t t fi f d t [Bl i R id ]pp




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Actual and target fineness of product [Blaine or Residue]

Actual mass flow rate (e.g. separator grits, water demand, etc.)




Electrical power consumption of the main equipment

Actual operation parameter of the main equipmentVictorvilleVictorville/ CA/ CAU.S.AU.S.A


(e.g. separator speed, damper positions)


Circuit material granulometry:

GeneralGeneral


g ySampling points










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Circuit material granulometry:

GeneralGeneral


Sampling point: r ProceduresClinker feed

1 x per

SievingGypsum feed H2O

g y




10 kg 1 x per TestGypsum feed H2O

50, 25, 16, 8, 4, 2, 1, [mm]

Additive No.1 feed H2OAdditive No. 2 feed H2OMill tl t t i l




Mill outlet material Pre-screening with 450 m sieveSeparator feed material

Separator grits material S fi l 1

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0.5 kg1 x

every hour

PSD from 1-450 m with Laser equipment (e.g. Cilas, Malvern,

Separator fines cyclone 1 Separator fines cyclone 2 Separator fines mix



Control loopControl loop Sympatec)

Fineness acc. to Blaine [cm/g]

Filter dust 1 (weighfeeder) Filter dust 2 (circuit dedusting) Filter dust 3 (mill dedusting)



Blaine [cm /g]Cement


Longitudinal sampling:

GeneralGeneral


g gSampling points at crash stop

1m 0.5 0.50.5 1m 1m 1m 1m 1m 0.51m 1m 1m




1.1 1.2 1.3 1.4 2.1 2.2 2.3 2.4 2.5 2.6 2.71.1 1.2 1.3 1.4




Sample weight:1st compartment: 1-2 kgpp




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1 compartment: 1-2 kg 2nd compartment: 0.5 kg

20 cm




20 cmVictorvilleVictorville/ CA/ CAU.S.AU.S.A


20 cm


Ball charge filling degree:

GeneralGeneral


g g g

Measurement by free height




M



TrompcurveTrompcurve 1. Measure average internal diameter, DippVentilationVentilation



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g , i2. Measure height, h, in three different points along

axis for each grinding compartment

For best results the measurement takes place in an



Control loopControl loop For best results the measurement takes place in an empty mill (mill feed stopped for approx. 10 min).




Mill material level:

GeneralGeneral


Inspection only at crash stopRecord the material level approx. each meter along axis



Material levelMaterial levelM




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Too high = above charge




Good material level

Good = below charge

Too low = >1 VictorvilleVictorville/ CA/ CAU.S.AU.S.A


Good material level for 1st compartment

Too low 1 below charge



GeneralGeneral


Inspection only at crash stopRecord the material level approx. each meter along axis







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Too high = > 50mm above chargeGood = approx. 20 mm




Good material level

ppabove chargeModerate = equal with ball charge



for 2nd compartmentToo low = >> 50 mm below charge



GeneralGeneral


Inspection only at crash stopRecord the material level before and after transfer points







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Mill internals condition:

GeneralGeneral


M ain mill drive:

1495 [kWh]n.a. [kWh]

Type of product: 16,72 [r.p.m.]72,67 [%]

T o tal mill feed: n.a. [t/h]

mill speedcritical speed

Crash stop information: power installedpower absorbed

OPC

Finish mill No. 2Longitudinal Longitudinal samplingsampling



T o tal mill feed: n.a. [t/h]F resh feed: n.a. [t/h]C o arse return: n.a. [t/h] 3,5 m x 9,6 m

3rd compartment1st compartment2nd

comp.

Free heightcalculation:Pabs= 1247 kW




M

+

1 - 4 1 - 2 1 - 8

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2,115 mm 1,290 5,380 mm -







Mill internals condition:

GeneralGeneral











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Ball charge sampling:

GeneralGeneral


g gSolution 1) Total sorting of ball charge










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18 20 25 30 40 50 60 Scrap



GeneralGeneral


g gSolution 2) Analysing the actual grinding media

composition by spot samples.1st t tLongitudinal Longitudinal

samplingsampling



1st compartment:

50 balls per sample

2nd compartment:Internals Internals conditioncondition



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200 balls per sampleDate: 23.02.2006Prepared by: Now

Avg. Piece weightInput Table

Customer Data:Grinding ballspp




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Project-No.: 33.420

Customer:

Plant:

Installation:

Compartment:

Ball - 60 50 40 30 25 20

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-

Monochamber (1/3 lifter - 2/3 class.)

Project:

2.4m x 5.0m w ith QDK 8,5-F

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Control loopControl loop891.80 g

Std. 886 g 513 g 262 g 111 g 64 g 33 gMax 1400,0 g 681,0 g 374,0 g 176,0 g 80,0 g 44,0 gMin 682,0 g 375,0 g 177,0 g 81,0 g 45,0 g 14,0 g

Piece Mass1 891,8 g 891,8 g2 886,2 g 886,2 g3 879,6 g 879,6 g4 878,0 g 878,0 g5 873,5 g 873,5 g6 873 3 g 873 3 g



6 873,3 g 873,3 g7 861,0 g 861,0 g8 860,6 g 860,6 g9 858,2 g 858,2 g



GeneralGeneral


g gSolution 2) Analysing the actual grinding media

composition by spot samples.




pc. weight mass-% pc. weight mass-% pc. weight mass-% pc. weight mass-% pc. weight mass-%60 24 19920 53,56% 3 2552 10,54% 3 2353 9,68% 0 0 0,00% 0 0 0,00%50 23 11112 29,88% 20 9269 38,28% 10 4651 19,13% 0 0 0,00% 0 0 0,00%40 18 4293 11,54% 35 8468 34,97% 19 4592 18,88% 5 1209 11,58% 4 952 4,96%30 13 1384 3,72% 28 2997 12,38% 59 6328 26,02% 28 2943 28,19% 63 6617 34,46%25 8 481 1,29% 14 835 3,45% 73 4369 17,97% 66 3923 37,57% 144 8576 44,67%

Results of grinding media sampling5

Ball

Sampling Point1 2 3 4




20 0 0 0,00% 3 93 0,39% 66 2025 8,33% 76 2366 22,66% 98 3056 15,91%Total 86 37190 100,00% 103 24215 100,00% 230 24316 100,00% 175 10441 100,00% 309 19200 100,00%

50,0%

60,0%

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30,0%

40,0%




N ameAvg Piece Weight

Installat io n -

0,0%

10,0%

0,5 1 1,5 2 2,5 3 3,5 4 4,5 5 5,5 60 mm 50 mm 40 mm 30 mm 25 mm 20 mm



D ate P ro ject . N o . 33.420C o untry -

Now

23.02.2006 -P lant

Avg. Piece Weight

-C usto merM ill dimensio ns -


Separator tromp curve:

GeneralGeneral


Define the sampling points










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GeneralGeneral


Define the sampling points







Separator feed material Separator feed material before splitterbefore splitter

Separator fines Separator fines material from material from each cycloneeach cyclone

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Separator rejects Separator rejects materialmaterial

Check the stableCheck the stableand




Record all main operation Record all main operation parametersparameters

Check the stable Check the stable condition of the circuitcondition of the circuit



parametersparameters



GeneralGeneral


Define the sampling pointsSampling point: r Procedures




Separator feed material

1 x

Pre-screening with 450 m sievePSD from 1-450 m with Separator grits




0.5 kg 1 x every hour

Laser equipment (e.g. Cilas, Malvern, Sympatec)Fineness acc to Blaine

material

Separator fines cyclone 1

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Fineness acc. to Blaine [cm/g]

Separator fines cyclone 2







Separator Ventilation:

GeneralGeneral


Basics: Air flow measurementSelect your equipment




Prandtl-Pitot Tube S-Type Tube







C t l lC t l l C ti f t i d ( 0 84)



Control loopControl loop No correction factor needed

Easy to operate within 15 angle

Only in low vortex channel

Correction factor required (~0.84)

Misalignment results in mistakes

Preferred for high dust loadedh lVictorvilleVictorville/ CA/ CA

U.S.AU.S.A


Not for high dust loaded channels channels


Separator Ventilation:

GeneralGeneral


Measurement points:

Separator circuit with cyclones Separator circuit with filterLongitudinal Longitudinal samplingsampling



Separator circuit with cyclones Separator circuit with filter







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= Air flow, Static pressure,VictorvilleVictorville/ CA/ CAU.S.AU.S.A


Temperature= Static pressure, Temperature


Mill Ventilation:

GeneralGeneral











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= Air flow, Static pressure,Remark: Consider minimum 10% false air intake after mill.



Temperature= Static pressure, Temperature


Weigh Feeder Calibration:

GeneralGeneral


ga) Static calibration - feeder not in operation

Zero-point - adjustment (localLongitudinal Longitudinal samplingsampling



control box, no load) Span adjustment with calibrationweight (local control box)



TrompcurveTrompcurve operate weigh feeder with defined

b) Calibration with feeder in operation (preferred if possible)

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operate weigh feeder with definedsetpoint and load material into truckfor e.g. 10 minutes, while mill is shutdown



Control loopControl loop weigh truck empty and loaded,calculate throughput and adjust controller if necessary




Instrument Verification:

GeneralGeneral


1) ElectronicallyLongitudinal Longitudinal samplingsampling



Check and adjust zero-point and span with e.g. mA-transmitter




2) Operation checkpp




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Compare control room indication with local manualmeasurement of temperature, pressure and flow




Adjust transmitters




Control loop Verification:

GeneralGeneral


1) Operation check record process parameters with

t l l i tiLongitudinal Longitudinal samplingsampling



control loop in operation overperiod of e.g. 6-8 hours withconstant production

record mill power consumptionInternals Internals conditioncondition



p pat counter (kWh)

Adjust control loopt ifpp




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parameters if necessary

Information on:



Control loopControl loop Available information at the CCR Control system Control strategy



First impression on operation Circuit stability


Thank you for your attentionThank you for your attentionGeneralGeneral








Questions?Questions?pp




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ball mill inspection procedure

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inspection proceduregeneral

regular health check

system performance

data base

months schedulecircuit