Gas purification techniques

Alkaline scrubber

In an alkaline scrubber acidous components are purified by neutralization with a base. Salts can form in this process which can be treated further. The blow off water is purified and then drained to the sewer.

The dosage of the base depends of pH. Generally the pH of an alkaline scrubber is between 8.5 and 9.5. One cannot make the pH very high because of the higher base usage at higher pH because of absorption of CO₂ in water. As from pH above 10 CO₂ solved as carbonate will be present in water as a result of which the base-usage will increase very strongly. The calcium carbonate will fall down also on the packing as a result of which will raise the pressure drop. Advised is to use softened water in an alkaline scrubber.

The advantages of a basic scrubber are:

Relatively compact
Very high disposal output
Can be built modular, multi-stage systems

The disadvantages are:

base usage, pH-guided
Waste effluent, If economically feasable, in certain cases, formed salts are treated further.

The application of the basic scrubber can be in the electricity industry, waste combustion installation, galvano-industry, chemical industry and chlorine production.

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