ALTRON silicon carbide nozzles in a weldable metal assembly for FCC regenerator air distributors.
The air grid decides how evenly the regenerator burns off coke.
Its nozzles decide how long the grid stays even.
Air grid nozzles in an FCC regenerator resist catalyst erosion best when the orifice is made of an abrasion resistant ceramic that also tolerates thermal cycling, such as ALTRON alumina bonded silicon carbide or NITRON nitride bonded silicon carbide. Blasch casts the ceramic orifice into a metal assembly that is welded in place of the existing steel nozzle, without changes to the grid. According to Blasch, ALTRON assemblies typically last two to five times longer than high alloy steel nozzles.
The air distributor grid, also called air grid or gas distributor, injects combustion air into the dense bed of spent catalyst. Each nozzle has an orifice sized for an even spread of air across the bed.
An FCC campaign runs 5 to 20 years, and the regenerator can only burn as evenly as the most worn nozzle in its grid allows.
Ceramics cannot be welded to a steel grid. The Blasch assembly holds the silicon carbide insert in a metal sleeve, and the sleeve is welded to the grid in the same position as the steel nozzle it replaces.
The orifice is cast to size, not drilled, and repeats from one nozzle to the next. Every nozzle in the grid starts with the same flow and keeps it.
Assemblies are built for the two common grid types, pipe distributor grids and plate style distributors, and copy the geometry of the existing nozzles.
Silicon carbide is the usual choice against catalyst erosion, but the casting method, the bond and the microstructure decide how it performs. A fully dense ceramic resists abrasion well and can still crack in a regenerator that cycles in temperature. ALTRON and NITRON were developed for this balance and have run in FCC regenerators worldwide for more than 30 years. ALTRON alumina bonded silicon carbide
The FCC unit converts heavy feed into gasoline and other higher value products, so regenerator efficiency goes straight into refinery margin. Nozzles that hold their orifice keep fluidization stable, coke burn efficient and catalyst losses down until the next planned turnaround.
The two to five times longer life is the range Blasch states for ALTRON assemblies against high alloy steel nozzles in FCC regenerators. Your result depends on catalyst, velocity and temperature cycling.
Blasch engineers described the material choice for abrasive refinery service, with a focus on alumina bonded silicon carbide air grid nozzles, in Hydrocarbon Engineering. Hard choices in abrasive service
The regenerator grid is one of several places where catalyst wears through steel.
Ceramic lined elbows for spent catalyst and transfer lines, where a refinery line at 690 °C went from days to over 12 months.
Linings for cyclones, dustbowls and diplegs that see the same catalyst at higher velocity.
Bubble caps, arrowheads and tuyeres for boilers and reactors with fluidized beds.
Yes. The assembly copies the outer geometry and the attachment of your steel nozzle and is welded in place without changes to the grid hardware.
Yes. Because each assembly is welded like a steel nozzle, worn or damaged nozzles can be cut out and replaced individually.
Both are cast for FCC service. The choice depends on temperature, cycling and catalyst velocity at your grid.
The grid type, the nozzle dimensions and orifice sizes, and the regenerator conditions. A drawing helps but is not required.
Send the grid type, the number of nozzles and their dimensions. A Blasch engineer works out the assembly for your regenerator.
