Acid Wet Scrubbing of Ammonia

Sulphuric acid (H₂SO₄), nitric acid (HNO₃), phosphoric acid (H₃PO₄) or ammonium sulfate (NH₄)₂SO₄ measurement in ammonia treatment by web scrubbing

For ammonia treatment in emissions, wet scrubbing is used. 

In acid scrubbing, a strong acid is added to the scrubbing liquid to react with the ammonia and to produce an ammonium salt, which can be safely discharged to a drain or wastewater treatment plant or sold as a liquid or solid fertilizer. 

In continuous gas-liquid absorption systems, the concentration of the recycled solution is always controlled to ensure the proper acidic condition for scrubbing (usually a pH of 3 and 6) and to maintain the driving force by acid replenishment. The dosage of acid and water is controlled based on the pH and concentration of the scrubbing liquid.

Vaisala Polaris™ process refractometer continuously monitors the concentration of the bottom product of the scrubber. The reading from the refractometer can be configured to show the preferred control unit, for example, Total Dissolved Solids (TDS) or density.

The in-line refractometer is used:

• to control the addition of fresh acid ensuring optimal conditions for ammonia absorption.
• to control the dilution of the acid by controlling the water and acid feed valves to achieve the target concentration. 

Learn the details of the ammonia treatment by acid web scrubbing from the application note.

Download the application note in PDF by filling the form.

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