Industrial Energy Efficiency Down Under

8/17/2019 Industrial Energy Efficiency Down Under

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“Industrial Energy Efficiency Down

Under”

New Zealand and Australian Case Studies

Dr James Neale & Hamish Wolstencroft

Energy Research Group

Industrial Energy Efficiency Division

The University of Waikato

Hamilton

New Zealand


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Research into improving Industrial Energy EfficiencyCompressed Air

Steam

Utility Loop Optimisation

Heat Recovery and Heat Integration

Pinch Analysis

Industrial Fluid Flow Optimisation

Renewable Energy Solutions

Distributed GenerationEnergy Audit Methodology Development.

Energy Research Group Overview


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Energy Research Group Overview

• Numerical ModellingComputational Fluid Dynamics Modelling

Proprietary Software Development

• Economic ModellingCapital Project Assessment

Energy Future Scenario Modelling

• Experimental Investigation & Analysis

Laboratory ScalePlant Scale


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Presentation Overview - Background

The Energy Landscape Down Under New Zealand

Australia

Compressed Air System energy SavingsOpportunitiesSystem Audits

Leak Management

Case Studies Air leak management

The Social or Human Dimension


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Presentation Overview – The good Stuff

Measuring a leak

Volumetric flow

Actual/Standard flow

Understanding leak types

Shape Size

Pressure Effects

Sound and Ultrasound Generation

Loss rate

Case Studies Revised Leak Guess-Timator

Software Tools for streamlined survey and reporting


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New Zealand Energy Landscape

NZ is entering an energy crisis

Lack of infrastructure investment

Cheap gas coming to an end

New generation costed at $2500 / kW by the ElectricityCommission. Cost to save electricity starts at $0 andgoes up.

Government committed to 90 % Renewable Electricity

Process Heat – almost left out of revised energystrategy


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New Zealand Energy Landscape – Greenhouse Gas

Emissions (2005 – Dry year)

Agriculture 48.5 %

Electricity 25 %

Transport 18.4 %

Industrial Processes 5.6 % Waste 2.4 %

Solvents 0.1 %

Notes• 66 % of Electricity is from Hydro

• 24.6 % increase in total 1990 emission levels


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NZ Energy Strategy

Energy Efficiency

Active energy efficiency programme (EECA)

Subsidised energy audits

Solar Hot Water SubsidiesCFL Light Bulb Subsidies

Industrial Programmes

Compressed Air Best practice programmes

Energy Efficient Motor SubsidiesOther work in progress


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Australian Energy Landscape

Energy

Large distance to market (gas)

High reliance on coal fired electricity

Reduced water storage and hydro electricity

Industrial process emissions up 16 %

Reliance on imported oil

Transport emissions up 29.9 %

Legislation introduced to mandate energy efficiencyprograms for industry - EEO


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Australian Energy Landscape – Greenhouse Gas

Emissions (2005 – Dry year)

Energy 55.6 %

Agriculture 15.7 %

Transport 14.4 %

Industrial Processes 5.3 % Waste 3.0 %

Land Use 6.0 %

Notes• 73.9 % reduction in land use emission levels

• 2.2 % increase in total 1990 emission levels


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Energy Savings in Compressed Air Systems

Compressed air is a unique utility for most plants since it is one of thefew where the plant has complete control over the production,distribution and use of the utility

80% of the electrical energy used by a compressor is converted to heat

No two air systems are alike and no two plants use air the same way. Itis important to take plant operations and requirements intoconsideration when analysing a system or changing to the system.

Compressed air is one of the most expensive sources of energy in aplant.

The overall efficiency of a typical compressed air system can be as lowas 10-15%

Opportunities to redistribute assets for optimum system efficiency


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Why Compressed Air

Increased Energy Costs

Climate Change and CO2 Emissions

10 to 40 % of Industrial Electricity Usage

20 to 30 % Cost Savings Commonly Found

Some cases of over 50 % savings

The Forgotten Utility


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Energy Assessment or System Audit?

Energy Assessment/Audit

Supply orientated

Limited ability to fully identify potential savings

A good start, but ….

System Audit

Focus on end use

Demand, Distribution and Supply orientated

Maximum Energy and Cost savingsCosts a little more to make 2 to 3 times the savings!


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Potential Demand Side Savings

Air Leaks → 10 to 50 % (Ave)

Artificial Demand → 5 to 50 % (Ave)

Peak Load Reduction → 10 to 20 % (Peak)

System Pressure Reduction → 4.5 to 9 % (Ave)

Energy SavingsCO2 Emission Reductions

Maintenance Savings


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Long Range Leak


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Man Made Leaks


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Man Made Leaks


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Leak by Design!


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Potential Supply Side Savings

True Demand Characterization – Must Come First

Compressor Run Order and Control

Minimise Unloaded Running Hours

Compressor SizingCompressor Technology Selection

Driers & Filters

Maintenance Savings

Total Savings of 10 to 30 %

Energy Savings

CO2 Emission Reductions

Maintenance Savings


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Savings Summary

Demand Side Savings typically 2 to 3 times the Supply SideSavings

Supply Side should only be optimised after the demand sideis under control!

Australian Model

Legislate change for large energy users

Limited government funding/assistance

New Zealand Model

Government funding conditional on demand side KPI’s

Demand Savings can be made that then can be re-invested insupply side improvements


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Initial Savings Estimate

Typical saving of 20 to 30 %

As high as 40 to 50+ %

Could be as low as


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What Is Measured

•Power Consumption (Power v Current)

•Pressure (gauge v absolute)

•Dew Point – Water Content

•Compressed Air Flow Rate (Supply/Demand)

Assumed flow (name plate)

Inline measurement – insertion options

Ultrasonic non-obtrusive measurement


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System Audit Report Contents

• Introduction

• Audit Methodology

• Compressed Air Demand Characterisation and Optimisation

• Compressed Air Distribution Summary

• Current Compressed Air Supply Summary

• Potential Compressed Air Supply Solutions

• Risk Assessment

• Potential Cost Savings Summary• Recommendations and Conclusions


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NZ Food Processing Examples

Leak Management

20 to 50 % savings

A single internal leak in a dust collector = 20%

Identification of critical areas for high spec fittings

Targeted maintenance


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•Artificial Demand Reduction

Cooling of bearings

Tank agitation

Air lances

Vacuum generators

Pneumatic conveying of powders


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•Peak Demand Balancing

Bag house pulsing

Automated powder packing

Purging product feed lines


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Bag House Air Demand

0

50

100

150

200

250

300

350

2/02/2007 12:00 2/02/2007 12:18 2/02/2007 12:36 2/02/2007 12:54

Time

A i r f l o w

R a

t e ( N

m 3 / h r )


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Bag House Air Demand

0

50

100

150

200

250

300

350

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Time (%)

A i i r f

l o w

R a

t e ( N m

3 / h r )

Inadequate Local Storage


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Artificial Air Demand

0

500

1000

1500

2000

2500

3000

1/02/2007 12:00 1/02/2007 15:00 1/02/2007 18:00 1/02/2007 21:00 2/02/2007 0:00

A i r D e m a n d ( N m

3 / h r )


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Artificial Air Demand

0

500

1000

1500

2000

2500

3000

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Time (%)

A i r D e a m n

d ( N m

3 / h r )

Artificial Peak


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Total Air Demand

0

500

1000

1500

2000

2500

3000

3500

4000

4500

2/02/2007 12:00 3/02/2007 0:00 3/02/2007 12:00 4/02/2007 0:00 4/02/2007 12:00 5/02/2007 0:00

T o t a l P l a n t D e a m n

d ( N m

3 / h r )


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Total Air Demand

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Time (%)

T o t a l P l a n t D e m a n

d ( N m

3 / h r )

Demand Peak = Over Capitalisation


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Leak Detection or Leak Management

•Leak Detection

•Leak Characterisation

•Fix Leaks →Lock in Energy Savings

•Data Management

Cost Benefit Analysis

Establish Rate of Reoccurrence

Verify Improvements

Proactive & Targeted Maintenance

Site and Corporate Reporting and Benchmarking


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Maintenance is more than plant reliability

Maintenance can have an IRR Air leak survey cost $6,000, saved $80,000 and shutdown

a 250 kW air compressor. Improved rate means less energy per tonne of product

Vacuum leaks fixed means happy operators

As maintenance professionals which budget do you getmeasured on?

Change in KPI’s for management to reflect new focusManagement Buy in to leak management programme

Maintenance Example


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Barriers To Success

•No Savings Until Leaks Are Fixed

•Technical Challenges

Scheduling of repair work

Maintenance priorities

•Social (Human) Challenges

Education

Ownership

Workload

Incentives


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Barriers To Success•No Savings Until Leaks Are Fixed

•Technical Challenges

Scheduling of repair work

Maintenance priorities

•Social (Human) Challenges

Education

Ownership/Attitude and Culture

Workload Management

•Fiscal ChallengesCost of leak survey and repair work

Risk to achieving projected savings


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The Solution

•Tailored Leak Management Program

•Certified Personnel : SNT-TC-1A

•Robust Data Management

Electronic Reporting

Historical Trending

Plant by Plant and Site by Site Comparisons


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The Solution

•Ultrasonic Leak Detection

Can identify leaks while plant is running

Non-intrusive

Sound level correlates to leak rate (dB)

•Customised Thresholds

Start with relatively high threshold

Lower threshold as plant improves

Allows a manageable work load

Can go straight to low threshold if desired, but …

80-20 rule applies


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Compressed Air Summary:

Significant energy savings can be made through correctauditing of compressed air systems

Demand Side optimisation must be addressed first, then the

supply side of the system may be optimised

The compressed air system must be analysed as a whole notindividual elements.

Human/Social barriers to change must be addressed if savings are to be locked in long term.


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Let’s Recap - Why do an Airline Leak Detection

Survey?

Compressed air is an expensive utility.

A simple programme of inspection and repair can reduce costs.

Thousands of dollars are wasted because of air leaks.

Why Use Ultrasonic Leak Detection?

Can be done while the plant is running.

Picks up leaks not audible to the ear.

Simple and accurate.

Implementation of a comprehensive air leak management planhas led to demand savings of over 30 %.

Optimum scheduling of air leak surveys with targeted approachto critical areas


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Air Leaks – All Different Shapes and Sizes

Let’s consider an air leak in a lot more detail

How to quantify the loss Loss rate

Cost (daily, monthly, yearly) Types of leaks

Why is pressure so important?

Examples – loss form an orifice Theory

Practice

Software tools to simplify an air leak survey


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Measuring a leak

Actual/Standard Flow

Turbulence in the flow generates Airborne Ultrasound.

Pressure

Leak

VacuumLeak

Volumetric Flow


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Pressure Effects – Why is pressure so important?

Any leak to atmosphere will expand from the internalpressure down to zero gauge pressure (atmosphericpressure).

Increasing the pressure increases the actual flow ratefor the same volumetric flow rate.

If the pressure in the leaking line exceeds a criticalpressure the volumetric flow through the leak orifice

will be choked (maximised).


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01

2

3

4

5

67

8

9

10

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

Exit Pressure (Bar)

V o l u m e t r i c F l o w

R a t e

( m 3 / h )


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0

5

10

15

20

25

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Pressure (Bar)

N o r m a l F l o w R a t e

( N m

3 / h )

4mm tube (Nm3/h)

6mm tube (Nm3/h)


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Leak Path Length Effects

Round Orifice Leak Rates

Internal Diameter

External Diameter

Leak Path Length Effects Lowers effective leak exit pressure

Gradual expansion of compressed air

Reduces loss rate


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Leak Path Length Effects – 4mm diameter orifice

0

5

10

15

20

25

30

35

40

45

50

0 1 2 3 4 5 6 7 8 9 10

Length (m)

F l o w

R a

t e ( N m

3 / h )

6 Bar

5 Bar

4 Bar

3 Bar

2 Bar


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Leak Path Length Effects – Extending the length

0

5

10

15

20

25

30

35

1 10 100

Length (m)

F l o w

R a t e ( N m

3 / h )

6 Bar

5 Bar

4 Bar

3 Bar 2 Bar


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Angle Of Approach

• Angle Effects The dB Reading Symmetry

Exit Path

Source Location• Variation In dB Increases With Increasing Pressure

Peaks @ 30-40 ° from central axis

Minimum @ 0 °


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Angle Of Approach – 100 mm From Leak

0

10

20

30

40

50

6070

80

90

100

110

120

0 10 20 30 40 50 60 70 80 90

Angle

d B

6 bar

5.5 bar

5 bar

4.5 bar

4 bar

3.5 bar 3 bar

2.5 bar

2 bar

1.5 bar

1 bar

0.8 bar

0.6 bar

0.4 bar

0.2 bar


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010

20

30

40

50

60

70

80

90

100

110120

0 10 20 30 40 50 60 70 80 90

Angle

d B

6 bar

5.5 bar

5 bar

4.5 bar

4 bar

3 bar

2.5 bar

2 bar

1.5 bar

1 bar

0.8 bar

0.6 bar

0.4 bar

0.2 bar


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010

20

30

40

50

6070

80

90

100

110

120

0 10 20 30 40 50 60 70 80 90

Angle

d B

6 bar

5.5 bar

5 bar

4.5 bar

4 bar

3.5 bar

3 bar

2.5 bar

2 bar

1.5 bar

1 bar

0.8 bar

0.6 bar

0.4 bar

0.2 bar


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Leak Types and Shapes

Many leak types exist yet all can be Simplified down toa few simple geometric shapes:Hole

Slit/crack

Slot

Tube

Loss rates and ultrasound levels depend on both thesize and shape of the leak orifice.

Larger orifice will have a lower ultrasound level for thesame loss rate (for a smaller orifice).


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Leak Types and Shapes - Comparisons

0

10

20

30

40

50

60

70

80

90

100

0 15 30 45 60 75 90

Angle ( deg)

D e c

i b e

l R e a

d i n g

( d B )

4mm Open End - 30.17m3/hr 15mm slit vert - 28.51m3/hr

10mm Slit vert - 21.79m3/hr 2.5mm Pinprick - 14.64m3/hr

2.5mm Open End - 10.06m3/hr 2mm Pinprick - 9.66m3/hr

5mm Slit vert - 5.18m3/hr 1.5mm Pinprick - 2.71m3/hr

1mm Pinprick - 1.54m3/hr


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Leak Types and Shapes - Slits

0

10

20

30

40

50

60

70

80

90

100

0 15 30 45 60 75 90

Angle ( deg)

D e c

i b e

l R e a

d i n

g ( d B )

15mm slit vert - 28.51m3/hr

10mm Slit vert - 21.79m3/hr

5mm Slit vert - 5.18m3/hr


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Leak Types and Shapes – 6 Bar (g) Slit

010

20

30

40

5060

70

80

90

100

0 15 30 45 60 75 90

Angle (deg)

D e c

i b e

l R e a

d i n g

( d B )

15mm slit @ 1m - 27.49m3/hr

10mm slit @ 1m - 20.43m3/hr

5mm slit @ 1m - 2.22m3/hr


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Leak Types and Shapes – 3 Bar (g) Slit

010

20

30

40

50

60

70

80

90

0 15 30 45 60 75 90

Angle (deg)

D e c i b e l R e a d i n

g ( d B )

15mm slit @ 1m - 12.31m3/hr

10mm slit @ 1m - 7.95m3/hr

5mm slit @ 1m - 0.81m3/hr


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Leak Types and Shapes – 6 Bar (g) Pinprick

010

20

30

40

50

60

70

80

90

100

0 15 30 45 60 75 90

Angle (deg)

D e c i b e l R e a d i n g ( d B )

2.5mm Pinprick 1m - 14.64m3/hr

2mm Pinprick 1m - 9.66m3/hr

1.5mm Pinprick 1m - 2.71m3/hr

1mm Pinprick 1m - 1.54m3/hr


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Leak Types and Shapes – 3 Bar (g) Pinprick

0

10

20

30

40

50

60

70

80

90

0 15 30 45 60 75 90

Angle (deg)

D e c i b e l R e a d i n g ( d B )

2.5mm Pinprick @ 1m - 8.30m3/hr

2mm Pinprick @ 1m - 5.81m3/hr

1.5mm Pinprick @ 1m -1.33m3/hr

1mm Pinprick @ 1m - 0.78m3/hr


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The Leak Management Process

Leak Detection

Tag Leak and Record Data

Input to Leak Database

Data Analysis and Report Generation

Investment Decision (Fix Leaks)

Work load Management

Repeat Survey

Historical Data Used to Determine Survey Frequency


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The Leak Management Process – Software Tools

PDA for in field data storage

Integrated Leak Database

Standardised Report Formats

Historical ReportingCorporate Reporting

Future Web Based Platform


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The Leak Management Process – PDA


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The Leak Management Process – Conclusions

Work Load is minimised In Field Data Recording

Data Analysis And Report Preparation

Information is only of value if: Accessed Easily Presented In Meaningful Formats

Extract Historical Data For Real Practical Benefit

PDA enables complex variation in leak rates for

different leak types to be easily incorporated with noadditional work load


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Acknowledgements

New Zealand Foundation for Research Science &Technology

New Zealand Energy Efficiency Conservation Authority

(EECA) Further information: [email protected]

Documents

Industrial Energy Efficiency Down Under