Measures are being taken to make optical gas imaging more cost-effective and accessible, but in the meantime the technology is still playing a significant role in the monitoring of fugitive emissions, reports Michelle Knott.
While fugitive emissions are a potential issue for any industry dealing with gaseous media, the regulatory spotlight has fallen on heavy industry and natural gas in particular.
It makes sense, since methane is a powerful greenhouse gas and the sheer volume of natural gas being produced for power generation and heating applications means that the generally accepted estimate of 1.5 to 2% of sales gas lost across the supply chain is a significant contributor to climate change.
However, it’s also important for other industries to monitor the escape of a wide range of hydrocarbons, which are often some combination of flammable, toxic or greenhouse gases.
Optical gas imaging (OGI) cameras can be used successfully to spot fugitive plumes of gas that are often invisible to the naked eye. Over the past decade, OGI technology has transformed the monitoring of such fugitive emissions and has become a go-to technology that’s mentioned in emissions regulations on both sides of the Atlantic.
“Finding leaks avoids accidents and explosions, so even though what’s written into legislation is on the environmental side of things, safety is a huge part of this as well,” says Steve Beynon, FLIR’s sales manager for North Europe. “I’m convinced that OGI technology has saved a lot of lives.”
FLIR is a leading supplier of thermal imaging equipment, including OGI systems for industrial applications. Earlier this year, the company’s GF320 and GFX320 cameras won a Technology Innovation Award at the Global Methane Forum. FLIR says these cameras help users in the oil and gas industries to visualise and geotag fugitive methane emissions up to nine times faster than traditional, ‘sniffer’-based methods.
OGI works by using optical filters to spot the infrared absorption characteristics of the gas or gases under scrutiny. In addition to methane, cameras can be tuned to find a range of hydrocarbons and other gases such as refrigerants, but it’s not a one-size-fits-all solution and Beynon warns that users need to approach OGI technology with care in order to get it right.
“OGI is widely used now and the majority of the time the technology is very beneficial for finding leaks,” he says. “But it’s not a point and shoot application and you need to be mindful of environmental conditions and the type of gas you’re looking at.”
Cost is another potential limitation, putting OGI beyond the reach of some applications for the time being. It’s pretty ubiquitous in natural gas production, for example, but not further down the supply chain in the transmission system. Beynon explains that FLIR is looking to address this in future by paring back some of the camera functionality to make OGI cameras that are more accessible in terms of cost. In the case of natural gas transmission systems, for example, providers are only interested in methane and don’t need the cameras to be able to spot propane, butane or other hydrocarbons.
First, the optical gas imaging camera detects the leak and then the ‘sniffer’ quantifies the leak. This is a major breakthrough that fulfils the true potential of smart leak, detection and repair technologies
Victor Gil González, project coordinator, Sensia
“I can’t say much more about it at the moment but ultimately, in the future, when you smell gas at your home or office you’ll call someone out and a cost-effective version of OGI technology will be in the hands of the people who come round in their van. Whether that’s five or 10 years away is an open question,” he says.
It’s also important to bear in mind that OGI used in isolation is a qualitative technology, showing where there are fugitive emissions but not measuring the rate of release. Some users team OGI with other technologies to check the rate of gas release once the camera has tracked down the leak, but that can be difficult if the leak is inaccessible.
FLIR has also partnered up with a company called Providence Photonics to come up with a system that can measure emissions at a distance using quantitative OGI (dubbed qOGI).
The system teams a tablet loaded with Providence Photonics’ QL320 software with a FLIR camera, which determines how sensitive the system is to a specific gas. This sensitivity can be measured relative to a reference compound, with the resulting value called response factor (RF).
For example, say an RF value for benzene is 0.75 in reference to propane. This means that the image of benzene is 75% as strong as the image of propane.
The EU has also been funding work to overcome some of the practical limitations of OGI – namely complexity and cost. The GaSeS project has been carried out by SENSIA, which is a spin-off of Carlos III University of Madrid.
The critical difference between most OGI solutions and SENSIA’s prototype cameras is that the infrared technology in the EU project is uncooled. “SENSIA has managed to bring uncooled infrared technology to an excellent operating capacity. This enables cheaper and incredibly efficient products that are more likely to enjoy market acceptance,” says project coordinator Victor Gil González. Uncooled cameras also have a lower number of moving components and a longer service life compared to cooled cameras under similar operating conditions, say the developers.
Working together with energy companies, the GaSeS team conducted a number of tests to validate and verify the suitability of SENSIA’s OGI systems. In particular, the team has presented a functional prototype of a fixed monitoring system designed for detecting gas leaks in large infrastructure. Besides detecting fugitive gases, the system has an additional unit for early and automatic detection of fire, a feature that could prove very useful in explosive gas installations.
Other project achievements include the development of hand-held portable equipment that allows technicians to make periodic inspections, and a system that can be placed on drones to inspect installations from the sky.
Lastly, the project partners designed an instrument for quantifying gas leaks that connects to the compact camera via Bluetooth. Gil González explains: “The optical gas imaging camera detects the leak and then the ‘sniffer’ quantifies the leak. This is a major breakthrough that fulfils the true potential of smart leak, detection and repair technologies.”
OGI delivers constant vigilance remotely
As well as OGI cameras being used to carry out surveys, fixed versions are also being used successfully to provide continuous emissions monitoring. In a recent application, an upstream oil and gas company implemented an OGI-based monitoring system from FLIR to check for gases leaking from their oil pads.
Not only has the new system reduced operating costs by 35%, according to FLIR, but it has also boosted public safety, since the oil pads are mostly in highly populated areas.
The user wanted to visualise 20 different hydrocarbons, including benzene, ethanol, methane, and propane and opted to deploy FLIR G300a OGI camera technology across its facilities.
These systems can adjust for changing conditions throughout the day and night, as well as seasonal changes and weather such as fog, rain or snow.
Within three weeks, the system spotted two leaks that would previously have been overlooked.
If a camera spots a leak, the system sends alerts and video to an automation supervisor via a mobile device. This prompts the supervisor to react immediately and deploy field technicians, who will typically repair any leaks within 30 minutes.
The new set-up enables the user to target its maintenance resources more effectively, as well as providing full-time coverage in place of checking each oil pad for just 15 minutes per day, as was previously the case.