SCR and SNCR
Plate catalyst
Also known as plate-type SCR catalyst, SCR plate catalyst.
A plate catalyst uses an array of parallel steel plates coated with the active catalytic material (typically vanadium / tungsten / titanium oxides) instead of an extruded ceramic honeycomb. The plates form open gas channels that are physically wider than honeycomb channels of equivalent surface area, making plate catalysts the preferred choice for high-dust SCR duty.
Where plate catalysts are specified
- Coal-fired utility boilers with heavy fly-ash loading
- Biomass plants where ash includes large agglomerated particles
- Waste-to-energy plants with sticky chloride-laden ash
- Iron-ore sintering plants and metallurgical off-gas SCR
Trade-offs vs honeycomb
| Factor | Plate | Honeycomb |
|---|---|---|
| Pluggage resistance | Higher | Lower |
| Geometric surface area per volume | Lower | Higher |
| Catalyst volume per MW | Larger | Smaller |
| Capital cost per layer | Similar | Similar |
| Vendor pool | Narrower | Broader |
Plate catalysts have a longer effective life on dusty duty because pluggage is the dominant lifetime-limiting failure mode there.
Cleaning compatibility
Sonic horns are particularly effective on plate catalysts because the open channels respond well to acoustic cleaning; the wide spacing means dislodged particulate has somewhere to go.
Related terms
Related terms
- Selective Catalytic ReductionSCR is the dominant NOx-control technology on industrial combustion plant. Ammonia is injected upstream of a catalyst that converts NOx to nitrogen and water.
- Honeycomb catalystA honeycomb catalyst is an extruded ceramic block with parallel square channels, the most common SCR catalyst form. High surface area but susceptible to channel pluggage.
- Corrugated catalystA corrugated catalyst uses corrugated fibre-reinforced sheets coated with active material. Lighter than honeycomb, particularly common on tail-end SCR and marine duty.
- Catalyst pluggageCatalyst pluggage is the physical blockage of SCR catalyst channels by large-particle ash, popcorn ash or ammonium-salt deposits. It causes ΔP rise and gas-flow maldistribution.