Acid scrubber

Application

• Removal of volatile nitrogen compounds:

  • NH₃

  • methylamine, dimethylamine, trimethylamine, ethylamine, hexamethylene diamine, …

• Removal of epoxides

  • ethylene oxide, proplylene oxide, butylene oxide

• ...

Principle

Acid gas scrubbing implies a transfer of volatile components from the gas phase to the liquid phase (acid conditions) with a subsequent neutralisation or hydrolysis of the volatile compound towards a non-volatile compound or salt.

In most cases, sulphuric acid (H₂SO₄) is used as scrubbing liquid because of its low cost and low vapour pressure. Other acids that can be used are hydrochloric acid (HCl), nitric acid (HNO₃), formic acid (HCOOH),…

The scrubber can be operated in a batch mode (e.g. operated with a 10% H₂SO₄ solution) or with an automated acid dosing control system as a function of a pH-measurement. In the latter case, a refreshment of scrubbing liquid based on the electrical conductivity (EC) is needed in order to prevent salt deposition. 

Under optimal conditions, very high (> 99%) removal efficiencies can be obtained in an acid scrubber for compounds as e.g. NH₃, trimethylamine etc. For the scrubbing of compounds like ethylene oxide, multistage scrubbers are provided with removal efficiencies up to 99.9999% or higher.

Scheme

Realisations