High or Low Temperature De NOx

High‑ and low‑temperature DeNOx systems

ERG provides DeNOx systems for industrial flue gas and process gas treatment, addressing nitrogen oxides formed in combustion and in reactions involving metals and acids. The selected DeNOx technology depends on gas temperature, NOx concentration and the relative proportions of NO, NO₂ and higher nitrogen oxides present in the stream.

High‑temperature DeNOx – SCR and SNCR

Through specialist partner companies, ERG offers high‑temperature NOx abatement solutions for process industries based on:

SCR (Selective Catalytic Reduction) – for high‑efficiency NOx reduction over a catalyst bed using a reducing agent (typically ammonia or urea), suited to elevated temperature flue gas.
SNCR (Selective Non‑Catalytic Reduction) – for NOx reduction by injection of a reducing agent directly into the hot gas, without a catalyst, where suitable temperature windows and residence times are available.

These systems are engineered to integrate with existing combustion plant, heat recovery and downstream gas cleaning equipment, targeting compliance with applicable NOx emission limits.

Low‑temperature DeNOx – gas‑phase oxidation and scrubbing

At low temperatures (typically below about 60 °C), conventional wet scrubbing of NOx is challenging. Nitric oxide (NO) is only sparingly soluble and nitrogen dioxide (NO₂) can be reduced in the scrubbing liquor to form NO, which then re‑enters the gas phase, limiting capture efficiency in a single scrubbing stage.

ERG offers treatment of chemically generated NOx using a combination of:

Gas‑phase oxidation using oxidants such as ClO₂ or ozone to convert NO into more readily scrubbable species; followed by
Multi‑stage scrubbing, configured to absorb the oxidised nitrogen species efficiently.

By employing V‑tex® technology within the scrubbing stages, it is possible to generate an effluent stream containing sufficiently high concentrations of salts (for example NaNO₂) to make it suitable for recycling and reuse within the client’s process, rather than a dilute waste stream.

You can see further details in ERG’s low‑temperature NOx abatement application brochure, or contact the process sales team to discuss a specific DeNOx duty.