Gas detection M
any steel companies have similar challenges tied to safety, productivity and environmental stewardship. They have the capacity to produce dozens of
tonnes of crude steel annually, host operations in multiple countries, and employ tens of thousands of people - all of which can prove an challenge to safely producing hot and cold rolled coils, sheets, galvanised sheets, tubes, wire rods, construction rebars, and bearings.
WORKER SAFETY IN THE STEEL INDUSTRY AND CONSERVING CARBON MONOXIDE Ensuring environmental responsibility and worker safety in all production units is a top priority for steel companies of all sizes. These facilities use blast furnace, coke oven, and Linz-Donawitz (LD) gases in the production process, the primary component of which is carbon monoxide (CO). CO is not only harmful to the environment but it can be life-threatening to workers. In most plants the gases created in the
production process are reused for power generation and reheating furnaces, which means that a CO leak could carry a devastating cost to the company in terms of money and energy. In addition to ensuring safe and efficient operations, many steel companies are also choosing to be environmentally responsible in their processes which is proven in some of their Environmental, Social and Governance (ESG) programmes.
TRIED AND TESTED TECHNOLOGY THAT DETECTS GAS LEAKS Gases are invisible 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 challenging to detect when using more traditional methods. In an effort to find a better
Detecting Harmful
carbon monoxiDe gas Leaders of the steel industry use FLIR GF346 Gas Detection Cameras to detect harmful carbon monoxide gas...
CO vent stack leak at a steel plant.
solution, steel operators have a unique solution to consider: 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 specialised 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 utilised, this technology is commonly used for the detection of hydrocarbons and VOC gases throughout the entire supply chain. OGI is approved by the US EPA as an alternative work practice and even designated as the best system for emissions reduction (BSER) for regulations in the oil and natural gas sectors. Companies such as Statoil, BP, Chevron and ExxonMobil all use OGI cameras to detect gas leaks. The FLIR GF346 uses a specially filtered
Image of a carbon monoxide (CO) leak in normal mode (top) and high sensitivity mode (bottom) from a blast furnace during normal operation.
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thermal detector to visualise CO and other harmful gases. The camera can be used to quickly scan for gas across wide areas and from a safe distance, without interrupting a plant’s production process. CO emissions can be a significant threat to steel manufacturing operations so emissions need to be closely watched. Even the slightest leak in a vent stack or pipe can have a devastating effect. The FLIR GF346 scans potential leak points rapidly from a distance and allows 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 needed to detect the lowest level of gas emissions using the GF346’s high sensitivity mode.
REAL WORLD EXAMPLES OF OPTICAL GAS IMAGING IN THE STEEL INDUSTRY A primary use for the FLIR GF346 is finding elusive leaks near the casting floor. Often, technicians are unable to detect the CO gas leak source in the casting floor area. Leaks occasionally begin in the late evening hours, so a lack of sunlight and the frequent change in natural airflow direction make it difficult to trace the source of leakage. With the help of a FLIR GF346 optical gas imaging camera, inspectors can scan all possible sources of the leakage point near gas piping both inside and outside the steel-making units. The GF346 can find leaks in a variety of
scenarios which can be up to 60m away from the casting floor. Gas can escape from a flange joint in a line that supplies gas to the hot strip mill reheating furnace from the gas mixing station. One remedy would be to close off and secure the area and communicate the findings for immediate corrective action, preventing an unsafe incident and closing off the source of the leak. In addition to casting applications, there are
extensive pipelines 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 steel making unit but can expand their inspection to gas lines outside the main facility premises. In these situations, the
January 2023 Instrumentation Monthly
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