Acid scrubber in the chemical industry

Solvents are often released in all kinds of chemical process lines. Solvents are often poisonous and flammable gases with a characteristic strong pungent odour, such as acrylates and acetates. Depending on whether an ester behaves acidic or alkaline, an acid air scrubber is a technically good solution to react ester contaminants from the air.

An acidic air scrubber is therefore a very good technique to remove alkaline components from an air stream. By adding an acid, the pH of the washing water is lowered and the alkaline components react with the acid to form a salt. The dosing of the acid is done by means of a pH control, in most cases the pH value of the washing water varies between 3 and 6.

Depending on the salt formed, more or less washing water is discharged, this is measured on the basis of density and/or conductivity. The drainage can contain up to 15 % of salts and is discharged or evaporated for reuse.

Various acids can be added, sulphuric acid (H₂SO₄) and nitric acid (HNO₃) are usually used. For specific applications, e.g. to capture ammonia (NH₃), the acid then forms ammonium sulphate or ammonium nitrate, both salts can be used as fertiliser or soil improver. Because of their alkaline character, amines and esters (odour components) can also be captured in an acid scrubber.

In case of strongly acidic air flows with, for example, high concentrations of hydrochloric acid (HCl), the scrubber itself will become acidic. In this type of scrubber, the maximum acidity level must be regulated by means of either draining or adding a base (alkaline scrubber). Combustion plants often use this type of wet scrubber.

The advantages of the acid scrubber are:

• Completely made of plastic to prevent corrosion
• Relatively compact
• Horizontal and vertical airflow possible
• Very high removal efficiency
• Can be built modular, multi-stage systems
• The formed salts can be reprocessed and reused

Air Solutions has experience with acid scrubbers in the following industries:

• Manure processing (ammonia)
• Composting (ammonia)
• Waste treatment plant (ammonia, amines)
• Fertilizer production (ammonia)
• Pharmaceutical industry (esters)
• Chemical industry (esters)
• Foundries
• Fish feed production (amines)

In addition to acid scrubbers, Air Solutions Holland also offers alkaline scrubbers, odour scrubbers, and plastic chemical storage tanks.

Quality marks:

• ISO 9002
• CE
• KIWA
• VLAREM
• DVS welding certification