Which material characteristic is most crucial for reformer tubes operating under high-temperature and high-pressure conditions in SMR?

The most crucial material characteristic for reformer tubes operating under high-temperature and high-pressure conditions in Steam Methane Reforming (SMR) is creep resistance. Creep is the tendency of a solid material to deform permanently under the influence of persistent mechanical stresses. In SMR, reformer tubes are exposed to extremely high temperatures (800-900°C) and significant internal pressure from the process gases. Under these conditions, the tube material will gradually deform over time, even if the stress is below the material's yield strength at lower temperatures. If the creep resistance is insufficient, the tubes will bulge and eventually rupture, leading to catastrophic failure of the reformer. High-chromium alloys, such as those containing 25% chromium and 35% nickel, are commonly used for reformer tubes because they offer excellent creep resistance due to their ability to maintain their structural integrity at high temperatures. The high chromium content also provides resistance to oxidation and carburization, further enhancing the tube's longevity. Creep resistance is therefore paramount to ensuring the safe and reliable operation of the SMR process.