Offshore Technology Reports – Next Generation Compressed Air Systems Solutions – Tamrotor by The Magazine Production Company

SPECIAL REPORT

Next Generation Compressed Air Systems Solutions Choose the Right Compressed Air Solution for Now and the Future A Ubiquitous and Flexible Energy Saving the Cost: A Good Idea What Air Can Do Good Air Does Good Work

Sponsored by

Published by Global Business Media

Custom EnginEErEd ComprEssors for offshore and topside installations

TMC offer Custom Engineered Compressors that are compliant with all requirements for offshore use. The Custom Engineered Compressors have a capacity range of 10-55 m3/min and are approved for non-hazardous zone and EX zone 1 and 2 installations. The compressors are compact with low noise level, can be delivered with electric, diesel driven and hydraulic systems, and can be water or air cooled. The compressors are approved by all major class societies, are ATEX certified and meet NORSOK requirements. All documentation requirements for offshore use are maintained in the renowned TMC documentation system. TMC Custom Engineered Compressors were recently chosen by Jurong Shipyard in Singapore for a series of 7 drillships to be operated by Sete Brazil. The 14 topside compressors will be containerized, diesel driven and air cooled. For more information contact us at mail@tmc.no

www.tmc.no

NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

SPECIAL REPORT

Next Generation Compressed Air Systems Solutions Choose the Right Compressed Air Solution for Now and the Future

Contents

A Ubiquitous and Flexible Energy Saving the Cost: A Good Idea What Air Can Do Good Air Does Good Work

Foreword 2 John Hancock, Editor

Choose the Right Compressed Air Solution for Now and the Future

Per Kjellin, Managing Director, Tamrotor Marine Compressors AS Sponsored by

Published by Global Business Media

Published by Global Business Media Global Business Media Limited 62 The Street Ashtead Surrey KT21 1AT United Kingdom Switchboard: +44 (0)1737 850 939 Fax: +44 (0)1737 851 952 Email: info@globalbusinessmedia.org Website: www.globalbusinessmedia.org Publisher Kevin Bell Editor John Hancock Business Development Director Marie-Anne Brooks Senior Project Manager Steve Banks Advertising Executives Michael McCarthy Abigail Coombes Production Manager Paul Davies For further information visit: www.globalbusinessmedia.org The opinions and views expressed in the editorial content in this publication are those of the authors alone and do not necessarily represent the views of any organisation with which they may be associated. Material in advertisements and promotional features may be considered to represent the views of the advertisers and promoters. The views and opinions expressed in this publication do not necessarily express the views of the Publishers or the Editor. While every care has been taken in the preparation of this publication, neither the Publishers nor the Editor are responsible for such opinions and views or for any inaccuracies in the articles.

© 2014. The entire contents of this publication are protected by copyright. Full details are available from the Publishers. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical photocopying, recording or otherwise, without the prior permission of the copyright owner.

TMC – Your Expert Partner for Compressed Air Solutions Custom Engineered Compressors for Topside and Offshore Installations The Myth of Oil-Free Compressors Compressed Air – An Expensive Necessity: Save 50% with TMC Smart Air® Trouble-Free Compressor Experience with TMC Planned Maintenance and Cost-Effective Spare Part Kits Original Parts Lower the Life Cycle Cost of Your Compressor

A Ubiquitous and Flexible Energy

John Hancock, Editor

A Useful Tool Different Types of Compression and Compressors Applications and Advantages

Saving the Cost: A Good Idea

Peter Dunwell, Correspondent

Cost Justifies Good Management Quality of Air Taking Efficiency Seriously Keeping Control for Efficiency

What Air Can Do

Francis Slade, Staff Writer

Prevention is Better Choosing a Solution Keeping Control Applications for Air

Good Air Does Good Work

John Hancock, Editor

Contaminants Can Affect Efficiency Cleaning the Air of Water and Oil Using Compressed Air in Offshore Oil and Gas Reliability Has To Be Designed and Built In

References 15

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NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

Foreword C

OMPRESSED AIR is, quite literally, the unseen

screw compressors, dryers and filters for any demand

hero of offshore oil and gas operations. It

of compressed air for marine and offshore use. The

is ‘unseen’ because air is invisible and a ‘hero’

article dispels the myth of ‘oil-free air compressors’

because there are few tasks in the sector which

and points out that this is a misdescription, as

don’t use it; from exploration and production to

impurities from the ambient air will not disappear when

decommissioning and dismantling. But, in an

the air passes through the oil-free compressor – the

industry that has to deliver more stringent than

only way to obtain oil-free air is proper filtration. TMC

average safety systems in a more hazardous than

supplies oil lubricated compressors and these have

average working environment; and that has to be

many advantages over oil-free compressors, including

able to ‘get the job done’ in whatever conditions

lower investment costs, considerably longer overhaul

nature might throw at it, compressed air is a

intervals and lower life cycle costs.

valuable and a valued resource and tool. Also, a

In the second piece we consider the ubiquity and

lot of risk management is about maintenance of

flexibility that have made compressed air a popular

the machinery and infrastructure to prevent any

source of energy over millennia yet are still valued

accumulations of flammable materials and about

in today’s workplace. Then Peter Dunwell looks at

maintaining a safe operating environment for the

some reasons for buying good quality equipment and

people who work in the sector. In both of these

running it efficiently and the enormous dividends that

processes, compressed air can deliver for offshore

can reap. Next, Francis Slade reviews the tasks to

oil and gas.

which compressed air can be usefully applied and

Compressed air solutions are employed in many

how controlling it can enhance its utility. Finally, we look

industries but are of particular use to the oil and

at some of the systems used to improve the running

gas sector where that ability to deliver power and

of compressed air solutions, how they work and what

to function without the direct risk of sparks is most

they can add to applications where air is employed.

appropriate in an environment where flammable fumes are an ever present hazard. The opening article in this Special Report looks at Tamrotor Marine Compressors (‘TMC’), which supplies

John Hancock Editor

John Hancock joined as Editor of Offshore Reports in early 2012. A journalist for 25 years, John has written and edited articles and papers on a range of engineering, support services and technology topics as well as for key events in the sector. Subjects have included aeroengineering, auto-engineering and electronics, high value manufacturing, testing, aviation IT, materials engineering, weapons research, supply chain, logistics and naval engineering.

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NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

Choose the Right Compressed Air Solution for Now and the Future

TMC

Per Kjellin, Managing Director, Tamrotor Marine Compressors AS Air compressors are essential to the operation of many onboard processes, tools and equipment. Choosing the right compressed air solution for these applications can be a challenge, given the increasingly sophisticated technical developments,

Smart Air® Compressor – your best investment

onboard and ambient conditions as well as concerns about smooth and steady pressure, maintenance costs and the drive to reduce onboard energy consumption.

TMC – Your Expert Partner for Compressed Air Solutions TMC supplies screw compressors, dryers and filters for any demand of compressed air for marine and offshore use, including Custom Engineered Compressors for offshore and topside installations and TMC Smart Air® energysaving compressors. TMC is the only supplier of compressed air solutions for the marine/ offshore sector that solely focuses on this market, and has the expertise and capacity to provide the right solution for any compressed air requirement on board.

Custom Engineered Compressors for Topside and Offshore Installations TMC supply compressor solutions that are compliant with all requirements for offshore use. Historically, the standard scope has been compressors and dryers for engine room

installation. However, as of August 2013 TMC launched a brand new product – TMC Custom Engineered Compressors for topside and offshore installations. These custom engineered compressors have a capacity range of 10-55 m3/min and are approved for non-hazardous zone and EX zone 1 and 2 installations. The compressors are compact with low noise level, can be delivered with electric, diesel driven and hydraulic systems, and can be water or air cooled. Diesel drive is provided by class approved marine diesel engines, complying with IMO Tier II, US Tier 2 and EU Stage IIIA. Air cooled units are delivered with hydraulic driven cooling fans and extensive noise dampening complying with current HSE requirements and the NORSOK standard. Water cooled models can be delivered for freshwater or seawater cooling.

As fuel costs continue to rise worldwide, selecting an energy-efficient compressed air system has become critical. With TMC Smart Air® technology, energy consumption is reduced by approximately 50% compared to conventional compressor technology. The cost saving is significant! Contact us on mail@tmc.no to find out how much you can save!

www.tmc.no TMC CUSTOM ENGINEERED COMPRESSORS

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NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

TMC Custom Engineered Compressors were recently chosen by Jurong Shipyard in Singapore for a series of 7 ultra deepwater drillships to be operated by Sete Brazil for drilling in the presalt fields in the Santos basin

TMC COMPRESSED AIR SOLUTION IN CONTAINER

Depending on the location onboard, the custom engineered compressors can be delivered in a container or skid mounted. Containers are made to customer specifications. The standard scope is with class approved offshore containers designed for rugged handling and with appropriate weather protection and painting system. The control of the compressor and drive unit is by a PLC-based customized controller, giving full control of all relevant running parameters and safety functions such as alarms and emergency shutdown functions. TMC Custom Engineered Compressors meet NORSOK requirements and are approved by all major class societies. They can also be delivered ATEX certified. All documentation requirements for offshore use are maintained in the renowned TMC documentation system. TMC Custom Engineered Compressors were recently chosen by Jurong Shipyard in Singapore for a series of 7 ultra deepwater drillships to be operated by Sete Brazil for drilling in the presalt fields in the Santos basin. The 14 topside compressors will be containerized with high specification offshore containers, diesel driven, air-cooled and will be used during well testing in connection with the burner boom operation.

The Myth of Oil-Free Compressors Specifications for compressed air systems on offshore installations and vessels often states “oil-free air compressors”. Usually no explanation is offered as to why the compressor type is specified instead of the actual air quality requirement, something which may indicate there is some confusion as to what is the best method for securing an oil-free output from the compressors’ air discharge. 4 | WWW.OFFSHORETECHNOLOGYREPORTS.COM

It’s a widespread belief that an oil-free compressor (a compressor with no oil in its internal system) produces oil-free air. This is not correct. Impurities from the ambient air will not disappear when the air passes through the oilfree compressor. When atmospheric air goes through a compressor the air volume is reduced, but the air still contains the same amount of impurities and water as the original air volume. Atmospheric air typically contains between 0.05 mg/m3 and 0.5 mg/m3 of oil vapor from sources such as exhaust or other processes. As oil-free compressors use large quantities of atmospheric air and atmospheric air contains oil vapor which can cool and condense in the compressed air systems, the use of oil-free compressors does not guarantee oil-free air. The only way to obtain oil-free air is proper filtration. An oil-lubricated compressor with proper filtration can easily achieve oil-free air of the highest purity class under ISO 8573.1. An oilfree compressor also needs proper filtration to achieve this. In air systems set up to achieve the highest air quality, oil-lubricated compressors – as supplied by TMC – have many advantages compared to an oil-free compressor. Benefits include lower investment costs, considerably longer overhaul intervals, lower life cycle cost as well as simpler and easier service and higher reliability in high ambient temperatures.

Compressed Air – An Expensive Necessity: Save 50% with TMC Smart Air® The major cost of an air compressor is not the initial purchase, installation, or maintenance, but energy consumption. Energy costs are a significant portion of any compressed air system’s total lifetime cost. The amount

NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

TMC

Smart Air® Compressor – your best investment

TMC SA 95 FUEL-SAVING COMPRESSOR

of energy required to run conventional air compressors for just one year can exceed the compressor’s purchase price. As fuel costs continue to rise and with new regulations for CO2 emissions, NOx and SOx coming into force, selecting an energy-efficient air system has become a critical decision for all owners. Reducing the fuel consumption related to the production of compressed air will help reduce these harmful emissions. Through its line of TMC Smart Air ® frequency-controlled screw compressors TMC offer their customers energy cost savings up to 50 per cent compared to conventional fixed-speed compressors. TMC’s variable speed compressors are designed to match output with demand, thus consuming exactly the right amount of energy to do the job. TMC offers TMC Smart Air® models across their range of marine and offshore screw compressors. TMC recently released a new TMC Smart Air® model, TMC SA 95, as part of the new mid-range series of compressors, TMC 86-124. This series closes a gap in TMC’s compressor range, offering a medium range compressor for all application areas from bulk handling to instrument air. TMC SA95 has a new frame for optimized footprint. Among other enhancements is a new optimized air-end, integrated patented oilmixing valve, new inlet valve, an integrated drip tray with drain, and a new separator receiver – still with TMC’s unique in-to-out oil filtration for greater safety. The series has a meticulously planned layout with minimal control air piping, and is equipped with plate coolers, IE2 motors and the new TMC CC1 controller. All cables are type approved, the el cabinet arrangements have been optimized, and there is simple access to

all service points. The series is available with or without noise canopy and designed for 55°C ambient temperature.

Trouble-Free Compressor Experience with TMC Your supplier’s service capabilities and response time should be key factors for choosing an air compressor. As the compressor installations are getting more complex, professional service and support is more important than ever before. TMS’s job is to provide the routines and tools you need to ensure correct and safe operation of your compressors and lower the life cycle cost of your compressed air system. TMC’s in-house technical support engineers are there to assist you via e-mail or phone. With their extensive knowledge and experience, they can guide the crew onboard through operational problems and troubleshooting. If you need assistance onboard, our service engineers are on call 24/7 – ready to board the next flight to reach you. TMC is represented in the main ports globally and have plans for further expansion. Current service points are Brazil, USA, Norway, Germany, the Netherlands, Singapore, UEA, China, Japan and South Korea. Service CDs with live video instructions are unique and help your personnel onboard safely perform routine maintenance operations.

Planned Maintenance and Cost-Effective Spare Part Kits All TMC compressors have controllers that automatically provide alerts when service or maintenance is needed. To make ordering and use of spare parts for the service operations more efficient and cost-effective TMC has introduced spare part kits.

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NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

COST-EFFICIENT SPARE PART KITS

Benefits include lower investment costs, considerably longer overhaul intervals, lower life cycle cost as well as simpler and easier service and higher reliability in high ambient temperatures

Benefits of using kits include lower price per part than when purchased item by item and time saved on ordering and checking. All parts that should be replaced during a given service operation are included, eliminating the risk of unscheduled stops due to missing parts. A service CD with live video instructions helps the personnel onboard safely perform routine maintenance operations

Original Parts Lower the Life Cycle Cost of Your Compressor When purchasing original TMC spare parts for your TMC compressors, sealed, distinct TMC packaging is your guarantee that you are receiving high-quality spare parts perfectly suited to your compressors. Using original TMC spare parts gives optimal performance for your compressed air installation, and the original parts â&#x20AC;&#x201C; that are manufactured to strict quality standards â&#x20AC;&#x201C; help to achieve energy saving, cost effectiveness and maximum air delivery.

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Contact Tamrotor Marine Compressors AS P.O. Box 3 Furuset NO-1001 Oslo Norway Tel: +47 22 91 85 00 Fax: +47 22 91 84 93 www.tmc.no mail@tmc.no

NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

A Ubiquitous and Flexible Energy

TMC

John Hancock, Editor

Smart Air® Compressor

What is compressed air and why is it such a useful component in industrial processes?

– your best investment A Useful Tool Compressed air has been an important factor across the industrial landscape for millennia in many and varied roles. From ventilation and powering the blacksmith’s furnace to delivering clean power and smelting metals from ore, directed and forced air has been a key contributor to industrial history. These days, from powering tools to thoroughly and quickly cleaning where no brush or material could reach, compressed air remains an essential ingredient in industrial and extractive processes. As Jason Miller explains in ‘A Brief History of Air Compressors’ 1 – “Air compressors have been around for literally thousands of years.” Originally, it was the bellows, without which civilization would never have managed to extract metal from ore and which also revolutionized the fabrication of weapons and tools. While bellows appear a far cry from modern compressors, the principle is the same – forcing air into a confined space with a limited outlet to deliver a greater than natural volume of oxygen to a fire or to generate significant physical force. However, as Miller continues, in early times, with only human or animal power available, levels of compression were limited. But, “With the industrial revolution, the mechanical air compressor was born. Engines running from steam power became the first method to power an air compressor. One of the first uses of a steam powered air compressor was in underwater diving equipment. This opened up whole new methods for under water exploration and even underwater construction. The compressed air could be pumped down to a diver and allow extended stays below surface. Compressed air was also much safer to use as a power source for early pneumatic tools and drills. For example, early rock drills were powered by steam. However, hot steam is far more hazardous than compressed air. A ruptured steam line can kill or seriously injure

a worker while compressed air is relatively benign. Steam powered rock drills eventually gave way to drills powered by air compressors.” A variety of compressors offer solutions for a wide range of applications today… compressed air remains a key component in industrial, manufacturing and extraction processes for much the same reasons that have always made it popular, plus some new ones related to safety issues in combustible environments. Although papers considerably longer than this one have been written on the process and operation of air compression, an air compressor can be simply described as a device that converts power (usually from an electric motor or an internal combustion engine) into kinetic energy by compressing and pressurizing air, which, on command, can be released in quick bursts.2 Of course it isn’t quite that simple but the statement serves as a fair summary of the principle behind compressed air. The thing about compressed air, over and above the functions identified in Jason Miller’s article, is its ubiquity; its ability to do most jobs that any other source of energy can do.

Different Types of Compression and Compressors Air compression is achieved in two ways; through positive displacement, forcing air into a chamber whose volume is decreased to compress the air, and negative displacement using centrifugal force to accelerate, then decelerate air, pressurizing it in the process. There are essentially three types of air compressor: reciprocating, rotary screw and turbo, sometimes known as axial. This is not a paper on the engineering of air compressors so we will limit ourselves to a brief description of each of the three main types. Reciprocating air compressors work by taking in a volume of air, confining it and then reducing the space in which it is confined, thus increasing the pressure. The process is usually achieved with a piston that acts on

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NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

Air powered tools can generate greater force than standard tools – a useful attribute working in an offshore environment where rust build-up can inhibit the rotation of fixings and the mobility of parts

the volume of air in its cylinder, the air being admitted to and retained in the cylinder by one set of valves and removed from the cylinder into the storage chamber by another set. While reciprocating compressors are useful in smaller applications, in larger industrial applications, rotary screw compressors are more likely to do the job. Usually using two meshing screws, these sorts of compressor continually push air through the compression cavities and into the storage chamber. As well as the volume of air they can continually compress, rotary screw compressors are smoother running than reciprocating machines. Finally, the centrifugal compressor produces a high-pressure discharge by converting angular momentum imparted by the rotating impeller (dynamic displacement)3. In order for this to be managed efficiently, centrifugal compressors rotate at higher speeds than other types, but they can also deliver higher volumes of compressed air because flow through the compressor is continuous. Against this, these types of compressors will require several sets of impellers to achieve high-pressure and therefore are more complex and expensive relative to other designs. Because of a process known as adiabatic heating, where compression of air causes it to heat, air compressors need a cooling system. This will frequently use either air-or watercooling and some rotary compressors might be oil-cooled.

Applications and Advantages Air compressors are used to drive processes and tools. In the offshore oil and gas environment, compressed air is an important element in well management with its ability to counter natural and perhaps unwanted pressures from within the well. It is also a very useful source of power for tools and, in this context offers several significant

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advantages. Unlike standalone electric tools, air tools can only work when there is a source of compressed air but they usually cost less than the standalone electric equivalents. Also air powered tools can generate greater force than standard tools - a useful attribute working in an offshore environment where rust build-up can inhibit the rotation of fixings and the mobility of parts. And lastly, upgrading the power of the compressor will automatically upgrade the power of all the tools using it, within their manufacturers’ parameters. Compressed air can also act as a tool itself, being used to clean and dry surfaces for better operations and improved safety. For a good summary of the advantages of compressed air, the UK Health and Safety Executive (HSE) offers the following 4… Compressed air is commonly used as a support service, on and off shore. It is used for tools, machinery, [and] operation of control and isolation valves. Its particular benefits are: • I t is relatively safe, compared with electricity, yet can supply quite powerful and compact tools. •O nly one supply pipe is required, making connection and disconnection simple. •A damaged supply hose does not pose a fire or electrocution risk. •P neumatic cylinders provide a low cost means of operating simple machinery. •P neumatically powered valves move quickly and precisely to the required position. •F ully pneumatic equipment can be used safely in the presence of flammable gases. •C ompressed air can be generated and stored on site. So having proved a trusty servant to industrial man over several millennia, compressed air looks to have an excellent future in all sorts of industrial applications and, given its particular safety benefits, in areas such as offshore oil and gas.

NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

Saving the Cost: A Good Idea

TMC

Peter Dunwell, Correspondent

Looking at the factors that can lose money and some actions that can stem the loss

Smart Air® Compressor – your best investment

Cost Justifies Good Management The initial outlay on a compressed air system is rarely small; in fact, the type of solutions that are used on offshore oil and gas platforms, with their safety related paraphernalia and stability requirements, can work out quite costly. But of course that initial outlay has to be seen in light of the number of jobs that a compressed air solution makes possible and the lifetime of the equipment delivering the solution. Therefore, it is important to get the right equipment from the outset. In particular, users will want to get compressors and control systems appropriate to the jobs they wish to do and will need to consider any solution in terms of its lifetime management. For instance, where safety and hazard assessment is concerned, the UK Health and Safety Executive (HSE) expects operators to take a holistic approach 5, “The hazards associated with an air compressor have to be considered over its complete operating/ maintenance cycle, not just full steady load operation. Maloperation/excursions/drive system failures and emergencies must all be covered. The hazards must be seen in context with the installation as a whole and be compared with all alternative compression strategies.”

Quality of Air As well as hazards that might affect the workforce using compressed air systems, there are hazards to the system itself including the quality of air that it handles and delivers. The US Department of Energy ‘Energy Tips’ publication for ‘Compressed Air’ explains on the matter of ‘ Determining the Right Air Quality for Your Compressed Air System’6… “Knowing the proper air quality level required for successful production is an important factor in containing compressed air energy and other operating costs, because higher quality air is more expensive to produce. Higher quality air requires additional air treatment equipment, which increases capital costs as well as energy consumption and maintenance needs.

The quality of air produced should be guided by the degree of dryness and filtration needed and by the minimum acceptable contaminant level to the end users.” The publication continues to explain that compressed air contaminants can be solid, liquid or vapors and can enter the system either at the intake or through the operation of the system itself. Air-quality depends on maximum particle size, pressure dew point and maximum oil content allowed. This latter is one of the main factors in determining air quality, especially where lubricant-free air is required. And of course, as always, the various systems used to reduce or eliminate lubricants from air will add to its cost and reduce its efficiency, especially if there is not proper maintenance. This matter of air purity is sufficiently important that there is an international standard for compressed air purity, ISO 8573.1, which provides a system of classification for the three main contaminants of dirt, water and oil, present in any compressed air system.

Taking Efficiency Seriously In fact, reducing energy consumption is an important consideration in the operation of any equipment including equipment used to deliver a compressed air solution. For this reason, the British Compressed Air Society suggests that compressed air users have a ‘Compressed Air Energy Efficiency and Compressed Air Audit’7 carried out to identify where energy is being wasted and where improved procedures could reduce waste and enhance efficiency. The society also offers a number of useful tips for compressed air energy efficiency. But isn’t only the air compressor itself that can be a source of energy loss or where energy efficient solutions can make a difference. The Carbon Trust8 explains that, “Although a lot of attention is given to the air compressor itself, the ancillary equipment for treating the air consumes energy and should, therefore, be viewed as a potential energy saving

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NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

initial outlay has to be seen in light of the number of jobs that a compressed air solution makes possible and the lifetime of the equipment delivering the solution SCREWS FOR TMC MARINE AND OFFSHORE COMPRESSORS

opportunity. This equipment includes dryers, filters and condensate drains.” Systems employ a number of methods to eliminate contaminants including dryers to reduce water levels and filters to remove oil and particulate contaminants (see final article). Another important contributor to inefficiency is leakage and it is generally believed that an average system will waste between 25 and 35% of its output to leaks. Kaeser Compressors9 estimates that a 3/8” leak in a system running at 100 psig (pounds per square inch) could cost as much as $31,200 per year! For systems operating at higher pressures the loss will be greater. Kaeser suggests that routine monitoring and repair is an essential part of compressed air system management. In a similar vein, Compressed Air & Gas Institute (CAGI)10 offers 10 practical steps towards saving energy in a compressed air system. Some systems even incorporate a waste heat recovery unit (WHRU) which applies the heat generated in the operation of the equipment and the compression of air to other useful purposes around the installation.

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Keeping Control for Efficiency The other significant contributor towards efficiency is control, so that the air is only delivered when it is needed and at the pressures required to that tool or job. According to the Carbon Trust (see above) there are three important reasons why it is worth investing time and effort in reducing compressed air costs through control. These are listed as saving energy and money by identifying and eliminating waste; improving the reliability and performance of the compressed air system; and reducing the system’s environmental impact through reducing electricity consumption and consequent carbon emissions. Essentially, the energy efficiency of a compressed air solution will be a factor of four things: the design and original manufacturer of the equipment; the location and the manner of its installation; the way it is used; and the quality of maintenance applied to it. Put like that, it looks a lot like applied common sense but it is surprising how often the familiarity of routine use can allow poor habits and far from common sense to become the norm.

NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

What Air Can Do Francis Slade, Staff Writer

TMC

Any job where consistent and significant power is the requirement will be a suitable job for compressed air

Prevention is Better Peter Dunwell’s previous article looked at some of the operational steps that can be taken to improve the efficiency of a compressed air installation: it makes sense to maintain and operate an air compressor and its associated equipment as efficiently as possible as part of an equipment lifecycle management program. But, of course, lifecycle management starts at the beginning with the selection, location and installation of the compressor.

Choosing a Solution The Carbon Trust has devised two sets of questions11 for those who are considering an installation: one set that the user should ask of themselves and the other that they should ask of whoever is supplying the solution. In summary, the choice of most suitable compressor will depend on a number of factors but primarily should take into account… air-quality required by the application/process; flow rate and pressure required; and initial outlay as well as long-term running costs. The best location for a compressor would be in a dry, clean, cool and well-ventilated area where both the compressor and its ancillary equipment such as dryers and filters will have the least work to do. The installation should ensure that any air inlets to the compressor room are, if possible, north-facing or at least in a shaded area with a grill to prevent foreign objects from entering the area. Air filtration should also be part of the installation to minimize levels of dust and dirt so that, altogether, the location and installation ensure the equipment’s most efficient operation and longest life. There are numerous packages on the market now which offer energy efficiency, including heat recovery, as an integral part of the solution.

Keeping Control An important element in any compressor management system is control, to ensure that the compressor’s output always matches but doesn’t exceed demand. Without controls, even where the air pressure required for a process or tool is at a low or medium level, the compressor will

Smart Air® Compressor continue to operate at full pressure, which would be wasteful. The controls will vary according to the compressor being used; for instance while small machines might use a start/stop control, that won’t be applicable to larger machines with limitations associated with starting and stopping. Throttling or modulating is usually only applicable to single stage screw machines operating more than 70% load; while load/off-load control (often called automatic) can be used with single stage screw vein compressors: in the larger piston machines it might be limited to a three step control for full load, half load and no-load. Variable speed control on oil-injected screw and vein machines allows system pressure to be maintained accurately by varying the motor speed and can save a lot of energy in an application where air demand fluctuates. Centrifugal compressors have a slightly more complex control system. As always these days, the latest control systems use microprocessors; digital technology can detect levels of demand and manage supply across the whole system of what will often be several compressors. Flow controllers can also improve the efficiency with which the system operates by stabilizing output without having to resort to unnecessarily high pressures to cope with fluctuations in demand and leaks. Some systems incorporate an air receiver or tank12 to act as a buffer between the compressed air system’s demand side (end users) and supply-side (compressors).

Applications for Air For the future, oil and gas extraction will be undertaken in ever more challenging environments (Polar Regions, beneath deep oceans, etc.) which will, in turn, challenge the designers, builders and operators of compressed air equipment to devise ever more robust and reliable products. Also, the growing need for decommissioning and dismantling of life expired installations will make increasing use of compressed air to tackle the many hazards associated with those processes. Bearing this in mind, a number of compressors have been designed specifically to meet the

– your best investment

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Oil and gas extraction will be undertaken in ever more challenging environments (Polar Regions, beneath deep oceans, etc.) which will, in turn, challenge the designers, builders and

TMC COMPRESSOR IN OFFSHORE CONTAINER

operators of compressed air equipment to devise ever more robust and reliable products

needs of offshore operators. This entails ensuring that the materials used in constructing the unit are corrosion resistant such as stainless steel and aluminum. It might also entail additional coatings such as Teflon to maximize durability. The needs mentioned above include the first requirement for any extraction industry of gaining access to the product which, in the oil and gas sector, entails surveying, for which purpose, compressed air provides the percussive power used in seismic surveys. Access also nearly always means drilling13. While compressed air can be used to drive the drill, its use is more often to deliver the percussive power to pulverize rock ahead of the bit and in balancing the increasing pressures encountered by the drill bit as it progresses to greater depths. Another job to which pneumatic pressure will be applied is in well testing where the pressure not only tests the integrity and

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productivity of the well but also can be used to balance the pressure exerted on the well head. And high pressure air can be used to inject stabilizing materials such as grout into the well. Away from the well head, compressed air can be found working in a number of applications such as pipeline dewatering and drying, underbalanced drilling (UBD), air drilling and pipework testing. Air can also be used to dry areas of the facility using dry air spread. Together with heat exchangers and steam generators, air compressors also support surface well testing operations. Plus, we mustnâ&#x20AC;&#x2122;t forget that, in any diving operations, compressed air is critical to the wellbeing of the personal involved and, in some areas of the platform, a higher internal air pressure is part of the health and safety system. There is no doubt that compressed air is a key component in any offshore operation.

NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

Good Air Does Good Work John Hancock, Editor

TMC

Maintaining compressed air pays dividends in lower maintenance downtime and more effective operation

Smart Air® Compressor – your best investment

TMC COMPRESSOR RANGE

Contaminants Can Affect Efficiency An issue mentioned earlier in this paper concerning the operation of compressed air systems is that, if the air they use is either dirty or wet, the system can at best run inefficiently and, at worst, fail when, for instance, fine particles of debris block safety related valves14. Air compression itself concentrates atmospheric contaminants, including water vapor which raises the dew point of the compressed air relative to free atmospheric air and leads to condensation within pipes as the air cools downstream of the compressor. Excessive water in compressed air, in either liquid or vapor form, can cause a variety of operational problems for users. These include freezing of outdoor air lines, corrosion in piping and equipment, malfunctioning of pneumatic process control instruments or fouling of processes and products. Many air powered tools are robust items which can operate with less than perfectly clean air. However, where compressed air is used to operate and actuate process instruments and control valves with their very fine nozzles, even low levels of contaminant can cause a malfunction which, in turn, means a maintenance event and unplanned down-time – never a popular matter on an offshore platform.

Cleaning the Air of Water and Oil Various methods are employed to manage dirt and water contamination, including filters and compressed air dryers, whose engineering and

operation would themselves warrant a complete paper. One system that is worth mentioning because of its association with compressed air systems is desiccant drying. “A desiccant air dryer protects… production, equipment and the quality of the end product by using desiccants to absorb moisture from the compressed air.”15 “Desiccant dryers are used for drying air in storage tanks or pneumatic systems and are beneficial in the drying of hygroscopic (waterabsorbing) resins. These dryers remove water from the air by passing it through a desiccant that absorbs moisture.”16 They are usually triggered by a pressure dew point sensor that, when it senses that the air being used has reached a predetermined level of moisture saturation, then operates the system. With desiccant dryers, the compressed air is passed through a pressure vessel including two ‘towers’ filled with a media such as activated alumina, silica gel, molecular sieve or other desiccant material. The desiccant material absorbs water from the compressed air. As it absorbs more water, the desiccant in one tower will become saturated. At that point, the dryer will switch towers and then use compressed air from the system to purge the saturated desiccant bed by simply blowing off the water that has adhered to the desiccant. The purpose of the desiccant is to bring the pressure dew point of the compressed air to a level in which the water will no longer condense, or to remove as much water from the compressed air as possible.

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NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

Reliable operation

has been drilling to tap underground reserves and extract oil and gas reserves from beneath the sea bed. These processes have developed the use of pressure to move the product and stabilize the space from which it has been extracted; they also take place in potentially explosive hazardous working environments which is where the qualities of air make it into a useful resource. Compressed air is often used in testing and balancing well heads and, when powering tools used within any potentially explosive environment, air is a much safer option than electricity, which carries the risks of sparking. Also, for myriad cleaning and purging tasks, compressed air can get the job done but with less wear on surfaces and components than mechanical or abrasive systems might cause.

is a prerequisite for any compressed air installation – nobody can afford unscheduled downtime to deal with failure. Because of this, designers and manufacturers of air compressors strive to minimize the work associated with their use and maintenance

Reliability Has To Be Designed and Built In TMC SERVICE ENGINEER AT WORK

Removing oil is slightly more difficult as the oil is often introduced from the lubrication of the compressor itself. There are filters designed to remove most oil from compressed air, but traces can get through which creates problems – for instance, oil in the air can make water removal more difficult. Rather than try to build the perfect filter on the assumption that it will be meticulously maintained in the work environment, compressor manufacturers have developed machines that do not use lubricating oil. However, these are complex and require thorough maintenance.

Using Compressed Air in Offshore Oil and Gas Modern applications for compressed air remain a mix of the traditional tasks for which they have always been applied with some new applications in industries that haven’t long existed in their present form. One such industry is the extraction of oil and gas. While oil and gas have been exploited for more than 2,000 years, it has been in comparatively recent times that there

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As with any equipment used in offshore oil and gas, reliable operation is a prerequisite for any compressed air installation – nobody can afford unscheduled downtime to deal with failure. Because of this, designers and manufacturers of air compressors strive to minimize the work associated with their use and maintenance. The two principal drivers of this will be customer/ user demands and, especially in the oil and gas sector, the increasingly challenging nature of work environments. So, use of the latest components and materials along with optimum accessibility to parts and extended maintenance intervals mean that not only are ‘down times’ less frequent but also they are shorter when they have to occur. Furthermore, this broadens the range of tasks for which air can be used and the effectiveness with which it can be applied. Given all of the above, compressed air for its ubiquity, its capability to deliver significant power and its clean and relatively safe operation is a good power source in an environment such as offshore oil and gas where all of those attributes are valued. For those reasons, its future in the sector seems assured.

NEXT GENERATION COMPRESSED AIR SYSTEMS SOLUTIONS

References: A brief history of Air Compressors http://ezinearticles.com/?A-Brief-History-of-Air-Compressors&id=867233

Wikipedia http://en.wikipedia.org/wiki/Air_compressor

The Engineering ToolBox http://www.engineeringtoolbox.com/air-compressor-types-d_441.html

UK HSE http://www.hse.gov.uk/research/rrpdf/rr076b.pdf

US Department of Energy http://www.compressedairchallenge.org/library/tipsheets/tipsheet05.pdf

British Compressed Air Society http://www.bcas.org.uk/compressed-air-energy-savings.php

Carbon Trust, ‘Energy efficient compressed systems’ http://www.air-receivers.co.uk/files/Carbon_Trust_GPG385.pdf

Kaeser Compressors http://www.kaeser.ca/Images/USGUIDE4_EnergySavingsGuide-tcm67-17483.pdf

Compressed Air & Gas Institute http://www.cagi.org/working-with-compressed-air/benefits/10-steps-to-savings.aspx

Carbon Trust, ‘Energy efficient compressed systems’ http://www.air-receivers.co.uk/files/Carbon_Trust_GPG385.pdf ... Go to Appendix C

Efficiency Vermont ‘Compressed Air Systems’

http://www.efficiencyvermont.com/docs/for_my_business/publications_resources/Compressed_Air_Guide_To_Savings.pdf 13

Wikipedia http://en.wikipedia.org/wiki/Drilling_rig#Rig_equipment

HSE ‘Compressor plant’ http://www.hse.gov.uk/pubns/priced/hsg39.pdf

Atlas Copco http://www.atlascopco.com/us/News/ProductNews/101115cd_bd_plus_desiccant_dryers_---_20101027_09_03.aspx

eHow http://www.ehow.com/facts_4922599_what-desiccant-dryer.html

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