Thermal imager spots the leaks in Swedish LDPE plant

Process operators at the Borealis (Vienna, Austria) high-pressure, low-density polyethylene (LDPE) plant in Stenungsund in Sweden are using a FLIR Systems (Wilsonville, OR, USA) optical gas imaging camera to detect potentially dangerous gas leaks, seeking infrared radiation signatures.

In the LDPE production process, ethylene -- a highly flammable hydrocarbon -- is converted into polyethylene in a high-pressure polymerization reaction. In the past, to detect any ethylene leaks, process operators at Borealis used gas "sniffers" -- devices which measure the concentration of the gas in one single location and generate a concentration reading in parts per million (ppm).

But with the purchase of the FLIR GF306 optical gas imaging camera, they are now able to detect leaks visually. What is more, process operators can scan approximately 80 per cent of the entire plant in about thirty minutes.

FLIR optical gas imaging cameras can spot the gas leaks because the gas absorbs infrared radiation, blocking radiation from objects behind it, causing the leaks to show up as either a black or a white plume in the thermal image, depending on whether the user opted for the 'white hot' or the 'black hot' settings. In the picture above, the valve is leaking ethylene, showing up as white smoke in the black hot thermal image.

The use of the IR camera, however, does not mean that the process operators have abandoned the sniffers completely. While the optical gas imaging cameras are used to detect any leaks, the sniffers are still used to quantify them.

Readers can download a copy of an application report and watch a video of the system here.

-- by Dave Wilson, Senior Editor, Vision Systems Design