NOx Scrubber — Nitrogen Oxide Removal

What Is a NOx Scrubber?

A NOx scrubber is a wet gas-treatment system that removes nitrogen oxides (NO and NO₂) from industrial exhaust streams through chemical absorption. It is widely used in nitric acid plants, fertiliser factories, metal surface treatment, glass melting furnaces, waste incinerators and power stations to meet increasingly strict NOx emission limits.

MDSJ Process (DUCON) engineers single-stage and multi-stage packing scrubbers, venturi scrubbers and hybrid systems tailored to each customer's NOx removal target, and delivers complete turnkey installation.

How NOx Scrubbing Works

Because NO gas is barely soluble in water, effective removal usually requires a two-step process:

1. Oxidation stage: NO is converted to NO₂ using an oxidant (e.g. H₂O₂, ozone or air oxidation tower)
2. Absorption stage: NO₂ reacts with NaOH or Na₂CO₃ solution in a packed bed → sodium nitrite/nitrate salts
3. Circulation system: pH control, make-up reagent dosing and spent-liquor management

Removal efficiency ranges from 70–99 % depending on the NO/NO₂ ratio, reagent choice and system design.

Industries We Serve

System Options

Regulatory Standards

NOx emission limits are defined by national air-quality regulations and — for EU member states — by the Industrial Emissions Directive (IED) and relevant Best Available Techniques (BAT) reference documents. MDSJ Process designs systems to comply with these limits and assists customers with regulatory documentation.