StaBlox compromised tunnel replacement for top-fired steam methane reformers, without waiting for a full revamp.
One tunnel down, the rest of the furnace still running.
The parts to rebuild it are already on the shelf.
A collapsed or damaged flue gas tunnel in a top-fired reformer can be rebuilt with StaBlox in hours instead of days once the debris is cleared and the floor is ready, because blocks, lids and bases for common tunnel sizes are kept in stock and are set dry, without mortar or curing. At the first two StaBlox installations in US ammonia plants, crews set a 43 ft tunnel in about four hours. The new tunnel stays in place when the rest of the furnace is rebuilt later.
After a collapse, the question is not only how fast the tunnel goes up, but whether it will fail the same way again.
Many reformers keep running with a damaged or missing tunnel. Next to everything else in a turnaround, one broken tunnel rarely feels urgent. The furnace notices anyway.
A published CFD study modeled a theoretical top-fired reformer with eight tunnels and then removed one outer tunnel. The mean temperature in the model fell from 956 °C to 916 °C, and to 836 °C in the area of the missing tunnel. Part of the flue gas left the furnace much faster, while another part recirculated. The authors point out that the reactions inside the tubes were not modeled and that the temperatures are meant for comparison. The full study is in the library: what a collapsed tunnel does to a reformer.
A collapsed tunnel is no reason to wait for the revamp: the tunnel you set now is already a tunnel of the revamp.
Because a StaBlox tunnel goes up quickly, it can be the last job in the furnace. Scaffolding gets simpler, and the difficult work can be scheduled first.
Where only the cover has failed and the walls still stand, StaBlox lids can replace the old covers on their own.
The tunnel can be taken apart and set again for inspection, so a repair today does not block access tomorrow.
The sequence for a single tunnel, based on the first StaBlox installations.
Remove the debris of the old tunnel and take its height, width and length.
Blocks, lids and bases in common sizes go out from stock, other sizes are designed to your dimensions.
Level the floor and the insulating brick layer, then set the bases at the spacing that sets the expansion allowance.
Stack the side blocks with their fiber seal and close the tunnel with the lids, ready for heat-up without curing.
A StaBlox replacement tunnel stands next to the remaining brick tunnels in the same furnace. When the whole reformer is rebuilt later, it stays where it is and becomes part of the full StaBlox system, in which an orifice insert sized from a furnace model by BD Energy Systems sits in every opening.
The blocks are cast in mullite bonded high alumina, a creep resistant grade, and are pre-fired in Albany, New York. StaBlox belongs to the Blasch self-supporting ceramic structures, built for hydrogen and ammonia plants.
Yes. A single StaBlox tunnel is set between the existing brick tunnels and runs beside them.
No. The blocks are set dry by a general refractory crew, without mortar and without curing time.
Yes. Where the walls are sound and the covers have failed, StaBlox lids can be fitted on their own.
It stays. The replacement is part of the StaBlox system, so the revamp builds around it instead of tearing it out.
The height, width and length of the tunnel, the number of openings and the furnace layout. A drawing is not required.
Send the tunnel dimensions and a photo of the damage. A Blasch engineer checks which stocked parts fit and what has to be made.
