Palisade user conference
This presentation is the property of its rightful owner.
Sponsored Links
1 / 31

Palisade User Conference PowerPoint PPT Presentation


  • 56 Views
  • Uploaded on
  • Presentation posted in: General

Palisade User Conference. Maximising the Net Present Value of Investment in the Maintenance of Assets - Ujjwal Bharadwaj, TWI Ltd, Cambridge, UK. April 22 nd & 23 rd London. Presentation Outline. Overview of TWI Risk Management Risk Based Asset Management

Download Presentation

Palisade User Conference

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Palisade user conference

Palisade User Conference

Maximising the Net Present Value of Investment in the Maintenance of Assets

- Ujjwal Bharadwaj, TWI Ltd, Cambridge, UK

April 22nd & 23rd

London


Presentation outline

Presentation Outline

  • Overview of TWI

  • Risk Management

  • Risk Based Asset Management

  • The Risk Based Approach to Plant Maintenance

    • Qualitative Assessment

    • Quantitative Analyses

    • Risk Based Optimisation

  • Benefits of using the RB methodology

  • Some issues

  • Questions


Overview of twi

Overview of TWI


What is twi

What is TWI?

  • Independent Research & Technology Organisation for welding and joining related technologies

  • Serves industrial member companies/government

  • Non-profit distributing and limited by guarantee of members

  • Derives from The Welding Institute and the British Welding Research Association


Key figures

Key Figures

  • 530 + staff

  • 300 graduate status

  • 3500 industrial members from

  • 66 countries world-wide

  • 4 major UK locations

  • 4 overseas operations and training bases


Where is twi hq

Where is TWI HQ?

On Granta Science Park 8 miles South of Cambridge


Twi uk locations

TWI – UK Locations

North East

Yorkshire

Wales

Cambridge


Twi overseas

TWI Overseas

  • Operations/training in Malaysia, Brazil, Iran & China

  • Associates in Australia, France, Ukraine & US

  • Agents/presence in US, India, Korea, Japan, Indonesia, Italy, Saudi Arabia and the United Arab Emirates, Kazakhstan.

Training base at Malaysia


Key industry sectors served

Key Industry Sectors Served

Aerospace

Automotive

Construction

Equipment,

Consumables & Materials

Electronics

Medical

Oil & Gas

Power


Risk management

Risk Management

  • Risk:

    • Combination of the probability of an event and its consequences (ISO/IEC Guide 73)

  • What is Risk Management?

    • Direction and control with regard to risk

    • In a financial setting

      • Concerned with events that pose opportunities for gain as well as potential for loss

        • Currency fluctuation, interest rates etc

    • In an engineering setting

      • Risk is a combination of occurrence of harm and the severity of that harm ( ISO/IEC Guide 51:1999 )

      • Harm is physical injury or damage to the health of people, or damage to property or the environment

  • Risk management process…


Palisade user conference

Risk Management Strategic Objectives

Risk Assessment

Risk Analysis

Risk Identification

Risk Description

Risk Estimation

Formal Audit

Modification

Risk Evaluation

Risk Mitigation

Risk Acceptance

Risk Communication

Monitoring


Risk based asset management

Risk Based Asset Management

  • Asset Integrity Management

    • Ensure integrity of engineered systems

    • ‘Fit for purpose’ throughout asset lifecycle

    • Ability of an asset to perform required function effectively and efficiently whilst safeguarding life and the environment

  • Objective: Maximize returns, minimize risks

    • Safety, Health and Environmental (SHE) risks

    • Business risks


Risk based asset management1

Risk Based Asset Management

  • Attributes of a good RBM for asset mgmt

    • Consistent, Transparent and Auditable

    • Identify potential and active DMs of plant

    • Plan inspection, such that residual risk for each DM is within acceptable limits

    • Increased reliability, safety and availability

    • Reduced scope of work for shutdown inspection


Failure rate over asset life cycle

Failure rate over asset life cycle

Infant mortality failures

Infant mortality failures

Wear out failures

Failure

rate

Constant random failures

Life of the asset


Failure rate over asset life cycle1

Failure rate over asset life cycle

Infant Mortality

Stage

Ageing/ Final Stage

Useful Life

Failure

rate

Operating Life


The ageing stage in a plant s life

The Ageing Stage in a Plant’s Life

  • Accumulated damage e.g.

    • Thinning due to Corrosion/ Erosion

    • Fatigue due to Cyclic Stresses

    • Creep due to high temperature

  • Remaining Life Assessment/ Estimates

    • Prediction for replacement/maintenance

    • Deterministic

    • Probabilistic

      • to capture the uncertainty involved


  • The risk based approach to plant maintenance

    The Risk Based Approach to Plant Maintenance

    • Risk is a combination of probability of an event and its consequence (API 580)

    • Step 1: Preliminary Risk Analysis of the System

      • By Qualitative Risk Analysis

      • Identify high risk components

    • Step 2: Detailed Risk Analysis of identified System components

      • By Quantitative Risk Analysis

      • Develop a probabilistic RL model of the degradation mechanism

    • Step 3: Optimisation

      • Such that financial benefit is maximised


    Qualitative risk analysis

    Qualitative Risk Analysis

    • System Analysis

      • ETA using @Risk Precision tree for all sub components

      • System boundaries, failure criteria specified

      • Data used

        • Historical (local)

        • Specific data

        • Generic

        • Expert Opinion


    Qualitative risk analysis1

    Qualitative Risk Analysis

    Component

    Likelihood

    Consequence

    Risk Score

    Elec Control

    High

    Medium

    48

    Gear Box

    Low

    Very High

    40

    Yaw System

    Low

    Medium

    24

    Entire Turbine

    Low

    Very High

    40

    Generator

    Medium

    High

    48

    Hydraulic

    Low

    High

    32

    Grid Connection

    Medium

    Low

    24

    Blades

    Medium

    Medium

    36

    Brakes

    High

    Medium

    48

    Axle/ Bearing

    Medium

    Medium

    36

    Mech Control

    High

    Medium

    48

    Entire Nacelle

    Medium

    Medium

    36

    Coupling

    Medium

    Medium

    36

    Tower

    Medium

    High

    48

    Foundation

    Low

    Very High

    40

    • qualitative analyses

    • semi quantitative analyses


    Quantitative risk analysis

    Quantitative Risk Analysis

    • Qualitative Analysis highlighted a structural

      component as high risk.

    • FMEA identified

      three main damage mechanisms

      • Corrosion

      • Scouring

      • Fatigue

    • Corrosion chosen to illustrate Risk Based approach

    • Probabilistic Corrosion Model gives failure rate with respect to years of service.


    Quantitative risk analysis1

    Quantitative Risk Analysis

    • Main input is distribution of corrosion rate (CR) reflecting the uncertainty involved.

    • Remaining life model:

    • RL= (Tstart - MAT)/ CR

      Tstart= Starting wall thickness (mm)

      MAT=Minimum Allowable Thickness to maintain integrity (mm)

      CR=Corrosion Rate (mm/yr)

    • Probability of failure is P(RL<0)


    Quantitative risk analysis2

    Quantitative Risk Analysis

    Marine Atmosphere

    Splash Zone

    High Tide

    Low Tide

    Quiet Sea Water

    Mud Line

    Typical Corrosi

    on Rate of Steel, mpy

    • Corrosion rate estimate

    • Curve fitted over historical values using @Risk

    • Expert opinion


    Quantitative risk analysis3

    Quantitative Risk Analysis

    • Repeated sampling of values from input distributions gives PoF based on RL for the considered DM.


    Quantitative risk analysis4

    Quantitative Risk Analysis


    Quantitative risk analysis5

    Quantitative Risk Analysis


    Risk based optimisation 1 3

    Risk Based Optimisation (1/3)

    • Risk expressed in Expected Values (EV)

    • EV= PoF x CoF

    • Consequences of failure mainly lost production

    • The Optimisation model finds the time of replacement of the plant when the Net Present Value (NPV) is the maximum over planning period

    • The optimisation weighs the EV of replacement with the EV of not replacing to identify the optimum year of replacement.


    Risk based optimisation 2 3

    Risk Based Optimisation (2/3)


    Risk based optimisation

    Risk Based Optimisation

    (3/3)


    Potential benefits from using the risk based methodology

    Potential Benefits from using the Risk Based Methodology

    • Target SHE and business risks

    • Maximize return on investment in O&M by risk prioritising

    • Better understand DMs

    • Better control and prevent unexpected system outages

    • Identify and eliminate gaps in existing integrity mgmt process at a site

    • Provide an auditable path for integrity mgmt


    Some issues

    Some issues

    • Limitations of the optimisation tool

      • For complex systems, non-linear optimisation tools required.

      • Increasing dependencies require more computing power.

  • Limitations of the methodology

    • Used mainly in the Ageing phase when time dependent damage has accumulated. Needs to be used in conjunction with an overall strategy for plant/equipment life management.

    • More suitable to business critical systems as opposed to safety critical systems.

  • Availability and quality of data


  • Questions

    Questions


  • Login