Decarbonisation Technology - November 2021

for the peep-door design and tube layout.

Figure 4: Analysing air leaks and temperature data from an SMR using the AMETEK Land Portab Thermal Imaging System. Figure 4 Analysing air leaks and temperature data from an SMR using AMETEK Land’s portable furnace thermal imaging system

the inspection team. In terms of optimising temperature homogeneity, reactive, single-point, manual data collection using a pyrometer will not provide the same volume of data as thermal imaging systems that employ automated, continuous monitoring of a measurement array. Whilst fixed monitoring systems provide this comprehensive data continuously in real-time, portable systems can also be valuable inspection and thermal survey tools (see Figure 3 ). The cost of adjustments designed to improve efficiency in reduced reliability may outweigh the benefit, especially if process temperatures are not accurately collected, recorded, and acted upon. Temperatures of 20°C (36°F) above design temperatures may halve the lifetime of the tube. Because of this, many plants operate conservatively to reduce the risk of material failures. However, running 10°C (18°F) below design temperatures, for example, results in a 1% productivity loss on an SMR. Similarly, a steam cracker running significantly under design temperatures will not crack enough hydrocarbon feed to produce a valuable product. Operating in the optimum surface temperature window is critical to an efficient process and material lifetime. 4

faster. Careful attention must also be paid to subsequent potential increases in NOx emissions and other changes in fired heater characteristics. These trends create new uncertainty, an increased risk of material failures and potentially unsafe conditions. 3 Traditional temperature monitoring is performed by pyrometers such as the AMETEK Land Cyclops L portable handheld pyrometer (see Figure 2 ), used throughout the ethylene, hydrogen, and syngas industry. Given new challenges and demands, other technologies can be used with the Cyclops L to provide more accurate and comprehensive temperature data for the tubes, burners, burner tiles, and refractory. These technologies include the AMETEK Land Gold Cup pyrometer, as well as both fixed and portable borescope thermal imaging systems. On an SMR, depending on furnace design, if temperatures approach or exceed the tube’s design limits as measured by the pyrometer, firing can be reduced, burners can be gagged, or burners may be shut off in extreme cases. This method is labour intensive and reactive, and potentially concerning conditions will only be acted upon if observed and recorded by

A careful analysis of the th m l image and te perature data in Figure 4 identified a significant a tube surface temperatures far below design limits, resulting in highly inefficient combustion and cat lytic reaction. Profile lines were used to ide fy the maximum, mean, and minimum temper across multiple gradients. Advanced software allows emissivity and background temperature adj be made n each tube to ensure correct compens tion. The thermal images in Figure 5 show ima collected from portable borescopes and issues relating to reformer temperature balance, flame impingeme t, hot spots/band, and catalyst damage.