Settling the SNCR injection layout before installation at a 30 MW waste-to-energy plant

870–1100°C

SNCR temperature window established by CFD

trial-and-error attempts on site

30 MW

electrical output of the plant

2 rounds

validation against design and experimental data

Context & problem

The SRF-fired grate boiler needed an SNCR system injecting urea to remove NOx. The SNCR reaction only works within a narrow temperature band; the flow behavior inside the furnace is complex, so the injection layout could not be judged before installation, and choosing the wrong position would lead to costly correction on site.

Approach

Diagnosing the current state: CFD of the base design revealed recirculation zones and bypass flow.
Establishing the effective 870–1100°C temperature window of the reaction inside the real furnace.
An assessment loop over the injection layouts (position, arrangement, nozzle type) against performance indices and NOx removal efficiency.
Model: urea decomposition and NOx removal reactions, droplet evaporation, residence-time particle tracking; validated against design and experimental data.

Results

The optimal injection layout was settled entirely before installation.
NO concentration at the secondary chamber outlet was lower than the base configuration at the same injection conditions.
Trial-and-error costs on site and the risk of shutting the furnace down for corrections were eliminated.

Value

For equipment that is installed once, like an in-furnace injection system, simulation acts as design insurance: the whole trial-and-error loop takes place on the computer, and on site only the verified configuration needs to be installed.

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About to install an injection system, a burner or equipment internals?

Settle the configuration by simulation before installation — it costs far less than one round of correction on site.

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