Many steel companies face similar safety, productivity and environmental challenges. They have the capacity to produce tens of tons of crude steel annually, operate operations in multiple countries and employ tens of thousands of people – all of which can prove challenging to safely produce hot and cold rolled coil, plate, galvanized sheet and pipe, wire rod, structural steel and bearings.
STEEL INDUSTRY WORKER SAFETY & CARBON MONOXIDE PROTECTION
Ensuring environmental responsibility and occupational safety in all production units is a top priority for steel companies of all sizes. These plants use blast furnace, coke oven and Linz-Donawitz (LD) gases in the production process, the main component of which is carbon monoxide (CO). CO is not only harmful to the environment, it can also be life-threatening for workers.
At most plants, the gases produced in the production process are reused to generate electricity and reheat furnaces, meaning a CO leak can have a devastating financial and energy cost to the business. In addition to ensuring safe and efficient operations, many steel companies also choose to be environmentally conscious in their processes, which is demonstrated in some of their Environmental, Social and Governance (ESG) programs.
Image of a normal mode (top) and high sensitivity mode (bottom) carbon monoxide (CO) leak from a blast furnace during normal operation.
PROVEN TECHNOLOGY THAT DETECTS GAS LEAKS
Gases are not visible to the naked eye and the effect of leaks is often very gradual, so identifying the source of a carbon monoxide gas leak can be difficult. The leaks can be masked by changes in airflow, making fugitive gases difficult to detect using more traditional methods. To find a better solution, steel operators need to consider a unique solution: an optical gas imaging (OGI) camera. While optical gas imaging is not widely used in the steel industry, it is a foundation of leak detection and repair (LDAR) technology used in a variety of other industries. The utility industry uses specialized OGI cameras to detect sulfur hexafluoride (SF6) gas leaks in substations and other areas within the electrical transmission supply chain. In the oil and gas industry, where OGI was first used, this technology is widely used for the detection of hydrocarbons and VOC gases throughout the supply chain. OGI is approved by the US EPA as an alternative work practice and is even designated as a Best Emission Control System (BSER) for regulations in the oil and natural gas sector. Companies like Statoil, BP, Chevron and ExxonMobil all use OGI cameras to detect gas leaks.
A leak in a CO pipeline was identified using a FLIR GF346 optical gas imaging camera.
The FLIR GF346 uses a specially filtered thermal detector to make CO and other harmful gases visible. The camera can be used to quickly search for gas over large areas and from a safe distance without interrupting the production process of a plant. CO emissions can pose a significant threat to steelmaking, so emissions need to be closely monitored. Even the smallest leak in an exhaust stack or duct can have devastating effects. The FLIR GF346 quickly scans potential leak sites remotely, allowing the user to pinpoint their source in real time. By ensuring there is sufficient Delta T (temperature difference between the ambient temperature at the leaking component and the background scene), technicians can achieve the optimal image contrast required to detect the lowest gas emissions with the GF346’s high sensitivity mode.
PRACTICAL EXAMPLES OF OPTICAL GAS IMAGING IN THE STEEL INDUSTRY
A primary use for the FLIR GF346 is locating elusive leaks near the casting floor. Often technicians are unable to identify the source of the CO gas leak in the pouring floor area. Leaks occasionally occur in the late evening hours, so the lack of sunlight and the frequent change in the natural direction of airflow make it difficult to locate the source of the leak. Using a FLIR GF346 optical gas imaging camera, inspectors can scan all possible sources of leaks near gas lines, both inside and outside steel plants.
CO leak from a vent valve detected with the FLIR GF346 camera.
The GF346 can find leaks in a variety of scenarios, up to 60 meters from the pouring floor. Gas can escape from a flange connection in a line that supplies gas from the gas mixing station to the reheating furnace of the hot strip mill. A remedy would be to cordon off and secure the area and communicate the results for immediate corrective action, prevent an unsafe incident and close the source of the leak.
In addition to casting applications, there is extensive piping within steel production facilities with the potential for dangerous leaks. For example, during typical LDAR scans, a user may not always find a leak in the steelmaking unit, but may extend their inspection to include gas lines outside the main plant campus. In these situations, the FLIR GF346 can detect leaks from main CO gas lines at a variety of points that feed the hot strip mill furnace with gas from gas mixing stations, such as: B. Flange connections. As a result, a facility can develop a routine to perform pipeline scans on a consistent basis. Using the GF346 to inspect ports, connections and other potential leak points provides an efficient way to further improve safety across a broader facility footprint and reduce emissions, helping the organization meet environmental protection metrics.
Steel industry operators can use the FLIR GF346 to inspect blast furnaces that produce molten iron for steelmaking. Blast furnaces have tuyeres attached to the furnace shell for supplying hot blast to the furnace. Frequent venting of CO gas from these tuyeres creates an unsafe and unhealthy atmosphere on the tuyere platform and above. Inspectors can use the GF346 to scan all air nozzles and identify leaking air nozzles from a safe distance. If a leak is discovered, operators can immediately take corrective action and update the tuyeres with a new welded design. After changing the air nozzles, a user can rescan the area with the GF346 to confirm that the leaks have been eliminated. As a result, operators now work in a safe, gas-free environment.
CO leak in a steel mill.
Hot strip rolling applications produce hot rolled sheet for automotive and LPG grades. The mills are fed via heating furnaces that use carbon monoxide-rich blast furnace gas and coke oven gas as fuel. Leaks of unburned CO can be identified by the camera and inspectors can quickly and safely find the source of the leak(s) in pipe joints. Once a leak is found, a technician can immediately take corrective action to eliminate the presence of CO near the furnace.
TIME IS MONEY
A key benefit of using a FLIR GF346 for LDAR inspections is the technology’s high return on investment. Gas leaks can cost money in a number of ways: lost product, additional safety costs, and increased downtime. Using an OGI camera for LDAR inspections can help the steel industry streamline their shutdown processes and procedures. These downtimes can cost a company a lot of money; An OGI camera like the FLIR GF346 can show operators exactly what needs repairing, allowing maintenance teams to plan for repairs and avoid unexpected shutdowns. There’s also a safety element: the addition of a telescopic lens to the FLIR GF346 allows operators to search for dangerous leaks from a safe distance, keeping them out of tight/hot work permit areas. The FLIR GF346 can also reduce downtime by allowing operators to identify areas of interest during regular operations and then schedule more detailed inspections for scheduled shutdowns. Because a turnaround can be 24/7 and hundreds of employees working 24 hours a day, the time it takes to search for leaks can be significant without the benefit of an OGI camera. Saving even an hour of tedious inspection time would help fund the camera.
The FLIR GF346 OGI camera can serve as a vital tool for steel companies, helping inspection teams spot problems before they become catastrophic and taking surveys without shutting down operations. The GF346 is ideal for monitoring facilities where it is difficult to reach components with portable contact meters such as gas sniffers or TVAs. Inspectors can scan thousands of components per shift without interrupting the process. Optical gas imagers also allow operators to detect severe leaks and locate their source while working from a safe distance outside the gas cloud. With the FLIR GF346, steel companies can improve worker safety, reduce environmental impact and help them meet regulatory compliance while increasing efficiency because this technology can operate without disrupting a facility’s production process.
About Teledyne FLIR
Teledyne FLIR, a Teledyne Technologies company, is a global leader in intelligent sensor solutions for Defense and industrial applications with around 4,000 employees worldwide. Founded in 1978, the The company develops advanced technologies to help professionals make better, faster decisions that save lives and livelihoods. For more information, visit www.teledyneflir.com or follow @flir.