A compilation of drop tests on StaBlox parts, with slow motion footage, aimed at the most common failure point of a reformer tunnel.
Most reformer tunnels fail at the top first.
So the test starts there.
The StaBlox drop test compilation shows StaBlox tunnel parts under impact, partly in slow motion. It addresses the most common failure mode of a steam methane reformer flue gas tunnel, the lid: tunnel lids crack from thermal stress, and large pieces of refractory from higher up in the furnace can land on them. The video lets you see how the precast lid and its joints take a hit.
The compilation brings together several drop tests on StaBlox components, with a slow motion sequence that makes the moment of impact visible. The focus is on the lid, the hollow cover that closes the tunnel and ties the wall tops together.
A finite element analysis of a conventional lid at a constant 1,900 °F shows only about 10 psi from its own weight. A temperature difference of just 10 °F between top and bottom raises that to about 1,500 psi, more than the hot strength of many refractories. Lids break from thermal stress, not from their span, and a cracked lid is then much easier to break with a falling load.
A lid that is already cracked from heat will break under almost any load, so the drop test only means something together with a lid that does not crack in the first place.
When you assess a tunnel design, ask two questions about the lid: how it handles the temperature difference across its thickness, and what happens when debris falls on it. The video answers the second, the published lid analysis the first.
Material values and design are on the page for the StaBlox flue gas tunnel system. If a lid has already failed, a tunnel can be rebuilt on its own, as shown in the StaBlox installation video. Why brick tunnels fail in the first place is explained in the paper on flue gas tunnel reliability.
They see a temperature difference between top and bottom that creates far more stress than their own weight. In a published analysis, 10 °F of difference produced about 1,500 psi.
From parts of the furnace above the tunnels that break off during operation or turnarounds, and from damaged lids themselves.
Yes. StaBlox lids can be fitted on their own, and a damaged tunnel can be taken apart and rebuilt.
Send photos or a description of the damage and the tunnel dimensions. A Blasch engineer checks what can be replaced.
