Eyes in the sky: part one

Developments in UAV technology for LNG inspection services and aerial survey work have been extensive over recent years, and the pace of progress remains unrelenting. The technology has transformed monitoring and maintenance regimes, adding greater commercial value and engineering accuracy – and proving itself against so many long-established ways of working by allowing assets to be inspected while they are live.

The UAV inspection method avoids the need for rope-access inspections and associated costly asset shutdowns, saving time and money as well as removing the risks of working at height. The accessibility and capability of the mission-critical data gathered for asset integrity inspections has been a ‘game changer’ for the LNG industry. It is not just the savings in terms of time and cost-efficiency that are decisive, but the numerous operational benefits that include improved monitoring and planning and the removal of risks to personnel.

Operational benefits such as these are invaluable against an industry background of meeting tough targets in long-term supply contracts and avoiding penalties. Workscopes for fabric maintenance can be quantified much more quickly and accurately through close visual inspection for example. CVI inspections generate thousands of images and high-definition video. All of this provides data to inform engineering decisions in a fraction of the time that it would take a large rope access team to cover an area such as a flare stack. Additionally, the versatility of UAV inspections also includes the ability to carry out precise asset information modelling, optical gas imaging and hyperspectral investigations of structures.

A technology with time and cost-saving advantages

Getting accurate assessments on the state of a particular asset quickly and in a relatively short period of time compares highly favourably to bringing in a rope access team to carry out an inspection that would involve a serious amount of safety equipment and take many days or even several weeks to plan and carry out. A UAV can be launched in a matter of minutes and deliver real-time high definition footage to an inspection team safely located on the ground below.

The detail picked up by onboard cameras is minute – even the smallest hairline cracks and defects are made crystal-clear. The level of detail coupled with the ability to review, slow down, and replay footage means that highly detailed inspections can be carried out to identify problem areas, common difficulties, or regular maintenance requirements. It also means that repairs can be precisely planned, based on the level of detail acquired; once again this brings further savings in the form of vastly improved planning.

Supporting planning in shutdowns and turnarounds

The efficiency of planned shutdowns can be further improved by using UAV inspection to precisely identify the condition and specification of parts that may need to be replaced. Parts and components are all too often simply not available off the shelf and have to be specially manufactured. This is a huge benefit to plant operators to be able to order up parts well in advance of them potentially failing.

As well as being much quicker to carry out, UAV inspections can often extend production by generating information that feeds into decisions about operational continuity. Many operators are now inspecting their assets on an annual basis using UAVs as part of a planned inspection regime. Elsewhere, other operators are tracking deterioration or already identified issues on a month-by-month basis to push back the time between shutdowns, something they are now able to do thanks to accurate records of asset condition that can be quickly updated on an ongoing basis.

Bringing objectivity to asset management

All of these advantages have made UAV technology a key player in helping LNG producers to design their asset management programmes. Everything starts with agreeing objective measures of guidelines and condition ratings, which are based on detailed images that identify precisely what each rating represents for each component. In this way, all categories are agreed from the outset and objectively with regard to true condition of components; detailed images allow for asset condition to be precisely graded. This also ensures the repeatability of inspections in terms of consistent results – each inspection is to exactly the same criteria. In this way, true condition can be reliably tracked over a period, with interventions being planned based on objective data that allow for highly accurate projections.

UAVs and the LNG industry

In the LNG industry, plant availability is always at a premium: Delivery slots for LNG producers are strictly enforced and any delays in shipments can give rise to huge cost penalties that derive from penalty clauses built into supply contracts. In view of this, it is perhaps not surprising that LNG producers are highly risk-averse in terms of any potential disruption to production. Traditional methods of inspection of course involve plant shutdowns, but they add to the feeling of insecurity in other ways too: no-one knows, for example, just what will be discovered.

By way of contrast, UAV inspection shows up defects in high-quality definition and while an asset is live. It means that potential defects in components can be spotted early and before they become an issue – and well ahead of any planned shutdown. Suddenly, maintenance regimes are underpinned by up-to-the-minute engineering certainty relating to all areas of LNG plant, include inaccessible flare stacks and flare tips. There are huge benefits in terms of reducing exposure to operational risk for plant and personnel, which go hand in hand with improvements in safety.

Other assets such as communications towers and waste heat boiler ducting at LNG facilities can also be inspected by UAV. Due to the immense heat generated, such plant is similarly impossible to inspect live using traditional inspections methods. CVI is combined with detailed thermography to provide a complete and objective view of asset condition – and all of this comes with the critical differentiator of large cost savings through maximised plant availability.

UAV inspection work at LNG plants is highly efficient in terms of time taken: Inspections can range from a few hours to a matter of a few days depending on the scale and complexity of the assets to be inspected. Apart from its inherent objectivity and high-definition detail, there is another way too in which UAV technology provides greater accuracy: UAVs, unlike human inspection teams, do not of course get tired. This is a major consideration in hot climates and in confined space inspections where human beings start to flag and their attention to detail and being ‘on task’ generally can be compromised.

Read the article online at: https://www.lngindustry.com/special-reports/29122017/eyes-in-the-sky-part-one/