UNLOCKING POTENTIAL

André Gerard GibsonKey Engineering Solutions

Improving Productivity Through Process

Optimisation

UNLOCKING POTENTIAL

UNLOCKING POTENTIAL

Agenda

1. Introduction – About Key & background2. Identification of the bottlenecks3. New control philosophy implementation4. Challenging designs to increase throughput5. Sustainability6. Demonstrate results

UNLOCKING POTENTIAL

About Key

Suite 5, 531 Hay StreetSubiaco WA 6008

• Hands on engineers with a passion for optimisation

• Engineering services for resources, building services, manufacturing & agriculture

• Specialise in automation and debottlenecking

UNLOCKING POTENTIAL

Industry Background

• Commodity prices continue to decline• Capital expenditure significantly reduced

Mining – Western Australia

UNLOCKING POTENTIAL

Automation in Industry

• Most facilities have a form of automation• State of automation varies from site to site• Allows for repeatability and predicatbility• Rarely utilised to its full potential

Current state

UNLOCKING POTENTIAL

Automation in Industry

• Equipment run rates controlled manually• Automation systems too difficult for users to

understand• Challenging to maintain over time• “Black Box” implementations

Some automation issues within industry

UNLOCKING POTENTIAL

Process Stability• Poor throughput stability

leads to overloads• Many automation systems

negatively impact stability

• Improving stability reduces breakdowns

• Allows for greater certainty to increase production

UNLOCKING POTENTIAL

• Equipment availability• Compliance to

preventative maintenance

• Overall shutdown effectiveness

Maintenance vs Production

• Increase Production

• Increase Production

• Increase Production

Department Objectives

UNLOCKING POTENTIAL

Why use this approach?• Simple to use & visualize• Easy to maintain• Ensures equipment run to design• Standard methods used in process control• Reduces variability and pushes active

constraint

Excellence = Quality x AcceptanceExcellence = Quality x Acceptance

UNLOCKING POTENTIAL

Identifying the bottlenecksPerformance workshops

Prepare for the workshop

Facilitate workshop

Close-out workshop

• Plan agenda & brainstorming activity• Invite experienced operations personnel from all disciplines• Send through any relevant details prior

• Explore opinions on issues limiting increased performance• Question why they are an issue• Ensure everyone has input

• Ask group for possible fixes• Provide examples of automated solutions• Summarise solutions from the group

UNLOCKING POTENTIAL

Identifying the bottlenecksData analysis

• Break system down into distinct areas

• Determine utilization calculation for each

• Develop utilisation histogram

Area Utilization calculation

Infeed % utilization = rate / max rate

Screening % utilization = average screen house bin level / nominal maximum level

Scrubbing % utilization = total rate / (max. line rate x number available lines)

Desands % utilization = % level in feed tank / nominal maximum level

Crushing % utilization = average crusher building bin level / nominal maximum level

Stacking % utilization = rate / max rate

Thickener % utilization = slurry export rate / maximum export capacity

Underutilized True when % utilization for all other areas is under an acceptable level (e.g. 85%)

UNLOCKING POTENTIAL

Identifying the bottlenecksConstraint utilisation visualization

• Live representation of previous histogram

• Provides real-time data on current bottlenecks & utilisation

• Easy to identify when the bottleneck shifts

• Useful tool for management decisions (e.g. capital projects)

UNLOCKING POTENTIAL

Implementation – constraint control

Standard process control “tool chest”

• Proportional, integral & derivative (PID) controllers– Simple feedback control– Controls process to a

desired setpoint– Commonly implemented

in industry and understood

UNLOCKING POTENTIAL

Implementation – constraint control

Standard process control “tool chest”

• Smith predictors– Predicts actual process

output (i.e. rates, level, etc) before actual measurement

– Eliminates dead-time issues (Delay)

– Allows for quicker PID response to correct

UNLOCKING POTENTIAL

Implementation – constraint control

Standard process control “tool chest”

• Override control scheme– Used for various PIDs

controlling the same equipment (e.g. screenhouse feeder)

– Lowest output controls process

– Ensures equipment runs to maximum limit of at least one constraint

UNLOCKING POTENTIAL

Implementation – constraint control

Putting it all together – Feed rate example

• Feed rate control for a conveying system with multiple feed points• Large dead-time prior to each weightometer feedback• Requirement to maintain consistent set-point tonnage

• Simple Smith predictor to mitigate dead-time• Filter = 1st order model of process• Delay = Weightometer dead-time (Delay3)

• Smith predictor with delayed PV input from previous weightometer

• Delay1 = time between weightometers• Delay4 = dead-time from feeder to

weightometer• Set-point adjusted to cater for

peaks/dips from previous controller

• Same process as previous controller• Correction for controller & process

variation maximized• Reduced variability & maximum

performance

Design & implementation: 8 daysCommissioning: 2 hours

UNLOCKING POTENTIAL

Implementation – constraint controlPutting it all together – screening example

Fines /Final Product

Tertiary

Secondary

Desands

W

W

W

W

PID

PVSP

CV

PID

PVSP

CV

PID

PVSP

CV

<

S S

PID

PVSP

CV

PID

PVSP

CV

PID

PVSP

CV

S S

<

P

PVSP

CV

P

PVSP

CV

P

PVSP

CV

• Six primary constraints to control• Three secondary constraints to control• Two separate feeder areas to control

ProductFeeders

DesandsFeeders

PID

PVSP

CV

PID

PVSP

CV

UNLOCKING POTENTIAL

Challenging equipment designs

• With now tighter control, minimised risk of overloading• Original designs come with generic assumptions that may not

always be true (e.g. motor winding temps calculated at ambient temperature of 60 degrees)

• Equipment designs cater for worst case scenario. If you can control the scenario, you can alleviate the risk

• Just needs a simple first principles engineering approach

Why can we challenge the design?

UNLOCKING POTENTIAL

Challenging equipment designs

Common equipment design process• Capacity requirements

specified prior to design• Multiple disciplines

involved in detailed design

• Each has separate design considerations

• Selection typically based on next size up

Discipline Design criteria

Mechanical Belt width/speed for ore profile, gearbox & coupling torque ratings, belt tension

Electrical Overall power consumption, variable speed drives, motor protection relays for motor protection

Structural Supporting structure sizing, cyclone/hurricane rating, extreme wind protection

Process Transfer chute design for ore flow & presentation, wear linear material and location in relation to product stream, particle sizing & material flow characteristics, downstream equipment capacity

Rate required = 5000 tph

Electrical, Mechanical, Process, Structural, etc.

Power required = 292kWSuitable motor = 315kW

UNLOCKING POTENTIAL

Challenging equipment designsExamples of challenging designs

- Ore profile of conveyor at capacity

- Torque & power within design limits

- VSD max. frequency of 50Hz

- Tripper designed for 10,000tph

- Tripper movement speed 0.5m/s

- Conveyor speed 4.5m/s

- Transfer chute at maximum capacity

- Increase VSD max. frequency to 60Hz

- Reduction in profile to 83.3%

- Reduce tripper speed to 0.25m/s in VSD

- Allows increase in maximum rate to approx. 10,500tph

UNLOCKING POTENTIAL

Sustainability

Excellence = Quality x AcceptanceExcellence = Quality x Acceptance• Quality

– Invest time in philosophy design– Correctly tune system prior to

completion– Cater for abnormal situations– Provide visual implementation

of what is in control– Develop “issues” log book for

operators and address problems– Coach operators in best

methods to control

• Acceptance– Prior to implementation, sit

with all operators– Be open to feedback from

operators– Make them feel like part of the

solution– Never reject operator concerns,

even when incorrect

UNLOCKING POTENTIAL

Results

• Reduction in Standard Deviation• Before: 1251• After: 925.2

• Whilst there is no increase in rate, variability reduction generated confidence for step change increase in rate set-point

UNLOCKING POTENTIAL

Results

• Reduction in Standard Deviation• Before: 3428• After: 2476

• Increase in rate• Before:

15,258tph• After:

16,671tph

UNLOCKING POTENTIAL

Conclusion• Simple problems don’t require complex

solutions• Methods used understood by site teams• Great results can be obtained if correctly

planned, designed & executed• Never underestimate the importance of

acceptance• Always be willing to challenge constraints

UNLOCKING POTENTIAL

Get in Touch

Address:Suite 5, 531 Hay StreetSubiaco WA 6008

@keyengs