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#Keynote – Pressure System Design Issues

Presenter: Crispin Hales – Hales & Gooch Ltd.

Despite the long history of successful pressure vessel, boiler and piping design worldwide, it is surprising how many failures in service still occur. The stories rarely get told unless they involve massive explosions, fires or loss of life. Everyone involved with pressurized systems stands to gain from understanding such failures and how to avoid them in future.
In this presentation three case histories will highlight some serious boiler, piping and interface issues easily missed during the design, manufacture, inspection, operation and maintenance of pressurized equipment in industry.
The first case involves a gas explosion during start-up of a dry-back 3-pass process steam boiler. The focus is not on the explosion itself but on the consequential ongoing failures with this type of boiler when repairs are made without understanding the basic design.
The second case shows how an apparently well-designed industrial ammonia refrigeration piping system can fail catastrophically under normal operation, releasing all the refrigerant to atmosphere. A remarkably similar failure at a different plant had been investigated and documented by the US Chemical Safety Board several years before, with recommendations for avoiding the problem in future. However, the designers may not have been aware of this report.
The third case concerns a thermal fluid vapor explosion in one of the world’s largest chicken nugget ovens, due to failure of a bellows in the tubing system connecting an internal heat exchanger to the external thermal fluid piping. The explosion resulted from a combination of interface issues between design engineers, suppliers, contractors, inspectors, operators and maintenance staff, as well as the piping and pressure vessel codes!
Overall, the presentation should help to generate helpful discussion on a series of issues that need to be considered during the design of any pressurized system.

About the presenter

Dr. Crispin Hales has 50 years of engineering design experience, principally in industry but also in undergraduate teaching and postgraduate research. For the past 30 years he has worked in forensic engineering, investigating more than 500 mechanical engineering failures, explosions and accidents mostly within the USA. Many cases have involved testifying at deposition or trial. After graduating in New Zealand and in the UK, Dr. Hales spent six years in Chicago designing and building high-pressure vessel equipment for the evaluation of materials under extreme temperature and pressure conditions. Projects included a $3 million refractory test facility for the US Department of Energy and a high-pressure vessel system for NASA’s creep rupture testing of super-alloys in 3,000 psi hydrogen. This was followed by a return to the UK where he completed a PhD in engineering design at Cambridge University. In 1989 he joined a Chicago forensic engineering company working on a wide variety of accident cases for sixteen years. In 2004 he founded Hales & Gooch Ltd. with Dr. Shayne Gooch in New Zealand, investigating mechanical engineering failures, providing expert testimony in legal disputes and consulting on engineering design. Based on the Hales & Gooch book, Managing Engineering Design, he also has contributed towards more effective design teaching and professional training for young engineers at Cambridge University in the UK, Canterbury University in New Zealand, and Northwestern University in the USA. Dr. Hales holds a B.E. (Mech.) degree from Canterbury University (NZ), an M.Tech. degree in Engineering Design from Loughborough University (UK) and a Ph.D. in Engineering Design from Cambridge University (UK). He is registered professionally as a Chartered Engineer and is a Fellow of the Institution of Mechanical Engineers. Dr. Hales is also a Fellow of the American Society of Mechanical Engineers and in 2002 received the Robert E. Abbott Award for long service to the ASME Design Engineering Division. In 2013 he received the Hills Millennium Award from the Institution of Engineering Designers for contributions to the management of engineering design.

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#1A – Practical Application of Design by Analysis (and FEA) to Pressure Equipment

Presenter: Fergus Rhodes – Rhodes Engineering and Design Limited

Design by Analysis (DBA) has been included in Pressure Equipment design codes since the 1960s, and general-purpose finite element analysis (FEA) software has been widely available on desktop PCs since the late 1980s. Yet for most engineering consultancy’s and designers of pressure equipment FEA is still not a routine activity. This presentation will give a brief overview of DBA, and detail examples of where these analysis techniques have proven useful on past projects. Barriers to the uptake of finite element analysis by engineering consultants and designers will be discussed. As well as advantages to using this approach, and potential pitfalls.
Three case studies from recent projects will be presented:
1. Design verification of pressure vessels with non-standard support arrangements
2. Assessment of localised corrosion on piping and pressure vessels
3. Design of an unlisted piping component
A summary will be presented of recommended minimum verification steps, and practical suggestions for how to efficiently and effectively assess results against code allowable stress limits.
Finally, a brief overview of advanced design by analysis techniques, such as elastic-plastic analysis, will be covered. Including when these approaches may be beneficial

About the presenter

not available

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#1B – Seismic performance criteria for marine oil pipelines

Presenter: Steve Holm – Aurecon

Marine oil pipelines transmit fuel from shipping tankers to tank farms some distance away. The lines typically run along a wharf and then underground to the various tank farms. Many of New Zealand’s marine oil pipelines are nearing the end of their service life and are up for replacement. Furthermore, New Zealand’s increasing seismic requirements for new-builds and historic wharf infrastructure can create many design challenges.
These pipelines are often classified as importance level 4 and can have regional lifeline status due to the necessity to provide fuel during emergency management situations. As a result, they are typically subject to very high seismic design loading, especially in high risk areas such as Wellington. Constructing a new pipeline in a coastal environment, on existing structures can often lead to a mismatch in seismic performance and a derating of the capacity of the pipeline due to the relatively poor performance of aging marine infrastructure or the presence of other risks such as rockfall, subsidence or tsunami.
Based on an actual case study project, this presentation aims to show how by defining risk-based performance criteria for the various required limit states, an economic outcome was achieved in the design of a proposed new marine oil pipeline. Advanced analysis techniques were used to demonstrate acceptability in varying levels of complexity. The principles used, could be applied to any new or retrospective seismic assessment of pressure equipment, particularly where seismic design loads are high.

About the presenter

Steve Holm is a senior mechanical engineer at Aurecon New Zealand based in Wellington. He has 20 years experience in the design of pressure piping and vessels in industries ranging from steam and power generation, oil and gas, geothermal and pulp and paper. He has also recently been involved with the drafting committee for Engineering NZ’s Practice Note 19.

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#2A – Condensation induced water hammer, New Zealand geothermal steamfield piping case studies

Presenter: Kevin Koorey – MB Century

The production and transport of steam and hot water from geothermal fields needs careful design and operational management to avoid condensation induced water hammer (CIWH). CIWH occurs when a steam space collapses upon mixing with cooler steam condensate or water. The resulting hammer event can be catastrophic. This paper details a number of cases where CIWH has occurred in New Zealand geothermal fields. Causes, events, and risk mitigations are discussed.

About the presenter

Kevin Koorey is the geothermal development manager at MB century. Kevin has 30 years’ experience as a piping and pressure equipment designer and project manager in New Zealand and on a number of offshore geothermal projects.

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#3A – A designer’s experience of industrial ammonia refrigeration system design

Presenter: Emanuel Tsamandakis – ETS Engineers Ltd

This presentation offers advice for simplifying the design analysis of low temperature industrial refrigeration piping using low carbon steel, and making pressure vessels more robust in earthquakes. The advice is based on based on many years of experience and many of these principles will also apply to all piping and vessel system design. Pressure vessels and piping systems should not be designed in isolation, they are both part of the same system, each influencing each other, and poor vessel selection can create real and unnecessary challenges for the piping designer. The presentation will look at real examples involving pressure vessels and plate heat exchangers and aim to show that saving cost in procurement of equipment will inevitably cost more in design and fabrication of the pipework.

About the presenter

Involved with design and design verification of pressure vessels, pressure piping (and their supports), cranes, as well as design of Building Maintenance Units (BMU’s) and lifting equipment for over 30 years

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#3C – 3D capture and modelling technology & Ductility factors in determination of seismic loads for piping.

Presenter: Luke Fischer – Beca

Luke will discuss two topics, the first being the use of 3D capture and modelling technology in the delivery of a smelter rebuild design for an overseas client. The approach to scanning, conversion of point cloud to model, and design modelling as well as materials take offs will be discussed. The second topic will be a discussion on the appropriate use of ductility factors in determination of seismic loads for piping, with reference to NZS1770.5 and Practice Note 19 as well as ASCE 7-10 and Eurocode 8 Part 4 (as applied in other countries/jurisdictions).

About the presenter

Luke Fischer is a Mechanical Engineer with degrees from Canterbury and Colorado Universities and 17 years’ experience in heavy industrial engineering. His experience in pressure equipment (piping and vessels) has been gained in the geothermal power, biomass power and forest industries, as well as metals processing industries in New Zealand, Indonesia and New Caledonia. He has also been involved in the design of significant petrochemical distribution and transfer systems for airports and similar facilities in New Zealand and overseas.

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#4B – Three Fitness For Service case studies exemplifying Integrity through Analysis

Presenter: Jonny Williams – LogiCamms Ltd (ASX: LCM)

Following the summary of API 579-1 at the 2016 conference, this is a presentation detailing three interesting Fitness for Service assessments of pressure equipment demonstrating how appropriate engineering analysis can be used to assure pressure equipment integrity, as well as reducing plant downtime and asset costs.
The three cases I will present are:
– Localised corrosion of a large (600mm) high-pressure (180barg) flange or Localised corrosion (80% wall loss) of a high-pressure piping tee
– Dented gas pipeline
– Critical crack sizing in a vessel head, used to select appropriate NDT inspection technique, and following Phased Array Ultrasonic Testing.
These case studies will showcase the use of latest technology techniques such as 3D geometry scanning and Finite Element Analysis. Using these case studies, I will discuss the challenges involved, the technology, and techniques used to overcome them, as well as the outcomes such as how the assessments increased safety, and understanding while reducing costs and risks.

About the presenter

Jonny Williams is a Principal Mechanical Engineer at LogiCamms in New Plymouth. He has 25 years industry experience using FEA, the last 9 years of which has focused on carrying out Fitness For Service assessments of Pressure Equipment throughout New Zealand and Australia.

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#2C – Electrode Boilers: Water/Steam chemistry, corrosion and control. New technology, new gremlins, new solutions

Presenter: David Addison – Thermal Chemistry

With the increasing application of electrical resistance boilers for both hot water and saturated steam applications and number of unique and interesting water/steam chemistry problems are becoming apparent worldwide. There is also a significant lack of technical literature and guidance related to the operation of these types of plants The International Association for the Properties of Water and Steam (IAPWS www.iapws.org ) has a technical working group between the Nordic and NZ branches of IAPWS actively working on the identification, understanding and resolution of issues that affect the reliability and performance of electrical resistance boilers. Electrode boiler problems, the science behind them and the potential solutions to resolve them will be discussed in this presentation

About the presenter

David Addison is the principal consultant of Thermal Chemistry Limited, a small, but very dynamic New Zealand based consultancy offering expert chemistry services and advice across the full spectrum of water/steam chemistry for clients in New Zealand, Australia and beyond in the thermal power (conventional and combined cycle and co-generation), geothermal power, and industrial power and steam industries. David has over 23 years experience in the water/steam industry including over 10 years based at the Huntly Power Station with ECNZ/Genesis Energy.

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#1C – Using An Innovative Low Damage Anchorage System For Industrial Tanks And Vessels

Presenter: Kaveh Sahami and Pouyan Zarnani – Tectonus Ltd

Enhancement of the seismic performance of liquid containers, especially strategic tanks or those with valuable contents used in the winery, dairy or petrochemical industry, has been in the centre of attention during recent years given the damages and economic loss experienced after severe events. The liquid storage systems are anchored to the ground with a limit number of connections and are taken into account as structures with minimum redundancy. Therefore, in such structures, the connection details are key design factors on the force and deflection demands imposed during an event. The conventional connections make the tanks to be either fully restrained or free for rocking motion, which generally creates a high level of force due to lack of ductility or large displacement demand due to uplift resulting in severe damage of the tank. However, a new approach is using a partially restrained connection to control both the deflection and force at the desired levels.
An innovative generation of anchorage system has been introduced by employing Resilient Slip Friction Dampers (RSFDs) as ductile self-centring hold-downs for industrial tanks and silos. This new tension-only damage-free anchorage mechanism mitigates the transmitted earthquake force to storage tanks by dissipating the input energy through friction without experiencing any damage, contrary to other common ductile yielding hold-downs. The self-centring feature of this damper also allows to control and limit the rocking motion of the tank and restore it to its original position, crucial for tanks with large height to base aspect ratios. Therefore, this new system does not require post-event maintenance and is able to resist against the possible aftershocks. Also, RSFD is flexible to be tuned for a different type of vessels depends on force and deflection demands.
In this presentation, through the validated experimental results, a comparison of the effect of RSFD anchorage system to other ductile concepts (necked-rod and buckling-restrained system) considering a real case study of steel cylindrical storage tanks has been conducted. This damage-free, tension-only, self-centring mechanism due to the flexibility of design compared to other systems considerably decreases the transmitted force which leads to less demand for designing tank’s barrel and also foundation. As a part of this presentation also some of the projects which have been equipped with this system will be introduced and discussed.

About the presenter

Kaveh Sahami is technical director at Tectonus group. He is an accomplished professional structural engineer with over ten years of research experience and also demonstrated history of working in the industry. He has extensive skills in seismic design and assessment of residential, commercial also industrial structures. He has been leading or contribution in a number of prominent projects equipping innovative low-damage damper technology as an efficient seismic solution to protect structures.
Dr Pouyan Zarnani is the Chief Technical Officer at Tectonus Ltd and the Academic Head of Structures Labs at AUT. He has been active in Earthquake Engineering field and being recognised as an entrepreneur successful in developing and commercialisation of innovative technologies to bring seismic resiliency to communities and industries (such as for wine and dairy storage tanks and silos). He has contributed to several projects in NZ and overseas through his innovative approach.equipping innovative low-damage damper technology as an efficient seismic solution to protect structures.

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#2B – Turbine Life Extension

Presenter: Chris Morris – Contact Energy

Wairakei Power Station has three 60 year old 30MW turbine generators in service. The turbine rotors of these are 15 keyed discs shrunk on to a spindle. The discs are large diameter, have very steep flanks with little distance between each disc. The complete assembly with blades weighs about 40 tonne. There is an industry history of the rotors catastrophically failing by cracking in the disc keyways. An ultrasonic NDT programme has been put in place to identify and monitor keyway and disc defects. This uses Pulse Echo, Time of Flight Diffraction and Phased Array techniques. Specialised equipment has been developed and built to do the complex work, together with appropriate QA tests. Defects including crack-like indications have been identified. Their growth rate is monitored. FEA has been done so critical crack size is known. The routine NDT monitoring programme, together with the high quality of the data, give assurance of continued safe operation.

About the presenter

Chris Morris is a mechanical engineer for Contact Energy Geothermal Group based at Wairakei. For the last twenty years, his primary focus has been the continued operation and maintenance of the steam and binary plant turbine generators at the Contact stations. He is the author of a number of papers on this and related subjects.

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#3B – An analytical approach to resolving field challenges

Presenter: Francis Forsythe – Worley

Francis will share a few examples of field repairs that were challenging and were resolved with design by analysis or alternative methods that needed independent design verification and acceptance by the Inspection Body.

About the presenter

Francis has 45 years of engineering devotion in mechanical, piping, project engineering and leadership in the petrochemical, refinery and oil and gas type industries, both onshore and offshore with experience in pressure piping, pipelines, pressure vessels, heat exchangers, boilers, furnaces, wellheads & wellsites, airport fuel handling system, tanks design & firefighting including inspection, testing, commissioning & maintenance programmes.

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#3D – Storage Tanks compliance and the new HSWA (Hazardous Substances) 2017 Regulations

Presenter: Eduardo Bermundez – Worley

Ed will provide an overview of obtaining Compliance for existing non-compliant Storage Tanks in New Zealand with a focus on the HSWA (Hazardous Substances) Regulations 2017, in particular Part 17, touching on its impact in Business, Health and Safety, and Process Reliability.

About the presenter

Eduardo (Ed) Bermudez is a Mechanical Engineer with a Master’s in Business with 20 years of Mechanical Construction, Commissioning, Maintenance and Reliability experience in Oil & Gas, Mining and Manufacturing industries across South America, Middle East and Australia/New Zealand.
Since establishing his family in New Zealand 4 years ago, Ed has been heavily involved with Worley Hawkes Bay in Maintenance Improvement roles in Pulp and Wood Products manufacturing plants, as well as capital projects in the Food and Beverage sector including process development to manage Hazardous Substance Regulations compliance for Industrial Complexes.

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#4C – Case study for a dissimilar metal weld repair in pressure piping

Presenter: Anita Zunker – PEi Group

Using 2 real world examples, the paper will present how a dissimilar metal weld repair Gr91 – SS was designed, developed and executed when the mechanism of failure is not properly understood within industry.  It will include discussion on how the requirements of AS/NZS3788 and AS3992 for weld repairs on aged equipment are applied to this type of problem.

About the presenter

not available

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#4D – Life prediction of hydropower equipment through Finite Element Analysis and Fitness-for-Service Assessment

Presenter: Harry Duncan – Quest Integrity

The first industrial hydro-electric power plant in New Zealand was commissioned in 1886, in Skippers Creek. While the dynamos installed in Skippers Creek were decommissioned long ago, several ancient hydroelectric power stations in New Zealand are in operation (as also happens in many other countries): Approximately 67% of the active hydroelectric capacity in New Zealand is generated by stations with 50 years or more.
With time, several components of those power stations were replaced by more efficient components: stay vanes, designed using modern engineering tools such as Computational Fluid Dynamic (CFD) generated considerable efficiency gains; redesigned propellers turbines allowed increasing the unit capacity in 40% at Kelsey power station.
However, the replacement of penstocks is considerably more seldom, and is usually connected with its failure beyond repair or presence of leaks extensively throughout its length. When well maintained, penstocks may show an indefinite life. It is, however, a challenge to determine maintenance requirements and acceptability of damage for equipment that was not designed to a known design code, such as many old penstocks.
Fitness-for-Service (FFS) assessments are used to determine acceptability of the damage observed in pressure equipment, and ASME FFS-1 is one of the most relevant standards for that purpose. As none of the design codes recognized by ASME FFS-1 (e.g. ASME BPVC, API Std 620) cover the design of penstocks, the assessment of damage and remaining life using ASME FFS-1 requires adjustment of the acceptance limits and considering the appropriate combinations of design margins and load conditions.
To allow for the Fitness-for-Service assessment of penstocks, Quest Integrity has conducted a thorough review of modern design codes used for their design (e.g. ASCE Manual 79). Methods for determining the acceptability of the typical degradation mechanisms (e.g. corrosion, fatigue, etc.) were developed by adapting the guidance provided in ASME FFS-1 to the design margins and loading requirements from ASCE Manual 79.
The use of FFS assessments in penstocks allowed for significant improvements in operation and optimization of maintenance strategy (including the extension of inspection intervals). Those assessments used a broad range of techniques, such as Linear and Non-linear Finite Element Analysis, Design by Analysis, Fracture Mechanics and others.
Therefore, it is beneficial to study such components to an extent in which their limitations and vulnerabilities are as well-known as if they were manufactured recently, so that the requirements to ensure they remain safe for operation can be determined. This work discusses damage mechanisms typically observed in hydropower equipment, how advanced engineering tools were applied to aging hydropower equipment to extend life and establish maintenance and inspection procedures to avoid unneeded replacement of expensive assets.

About the presenter

Engineer

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#4A – Fracture Mechanics FFS Assessment of a Cracked Dryer using XFEM

Presenter: Don Cambell – Matrix Applied Computing Ltd, Macky Engineering Services Ltd

Four crack like indications were discovered in the dryer heads during a recent NDT inspection of a yankee dryer at the Aseleo plant. These had not been picked up in previous inspections and a FFS assessment of the cracks was ordered by the inspection authority. The dryer is subjected to thermal, gravity, pressure, external roller and rotational loads during startup and operation. The major crack of interest was on the dryer head and was approximately 30mm long the 9mm deep and stress intensity solutions in ASME FFS-1 did not adequately cover the geometry, crack orientation and crack location. A global ¼ model of the dryer was developed as well as a submodel of the region of interest. Two assumed crack surface geometries were developed; rectangular and semi-elliptical and inserted (as separate cases) into the solid model geometry of the submodel. A refined hexagonal mesh was used in in the submodel in the region of the crack and the stress intensities computed using a J integral for the stress distribution for the total peak load and also for the change in load during a rotation of the drum. These stress intensities were then compared with the fracture toughness of the cast iron material to check for a factor of safety against rapid brittle failure. For crack growth the change in stress intensity during a rotation was computed and compared with the threshold stress intensity required to grow the crack. There was an adequate factor of safety against both sudden brittle failure and crack growth and thus the dryer was deemed fit for service. However, due to the lack of information on the dryer material, it was recommended that the crack be inspected at annual shutdowns.

About the presenter

Don Campbell heads the computational group at Matrix Applied Computing Ltd which specializes in advanced non-linear solid mechanics FEA, fitness for service (FFS) assessment and computational fluid dynamics. Don brings close to 50 years experience in the use of commercial FEA software for a vast range of different applications.
Bill Macky worked as a design engineer for Robt Stone specializing in the design and fabrication of pressure vessels and tanks before starting his own company offering pipestress, pressure vessel and tank design and analysis and is an integral member of the Matrix team as well as having his own clients in the process, utility and manufacturing industries.