The absorption scrubbers are used to reduce gaseous contaminants.
Absorbable contaminants are usually inorganic compounds, such as:
- Ammoniac NH3
- Hydrogen Sulphide H2S
- Hydrogen Chloride HCl
- Sulphur dioxide SO2 etc
- Exhaust gas from galvanic systems – contaminants: HCl, NH3
- Exhaust gas from core shooters – contaminants: Amines, SO3
- Exhaust gas from semi-conductor production – contaminants: HCl, NH3, SiH4
- Exhaus gas from sewage works – contaminants: H2S, NH3
The exhaust gas streams from the production processes are decontaminated in absorption scrubbers. The principle of the absorption lies in the solubility of the contaminated gases in scrubbing liquids. If the contaminated gases are separated out exclusively due to their solubility in the scrubbing liquid, it is a physical absorption. The degree of separation is largely determined by the solubility equilibrium of the contaminated gas. If this equilibrium is reached, the physical absorption stops. The chemical absorption is not limited by the solubility, since in this case, the gas dissolved in the scrubbing liquid is chemically converted. Both the absorption capacity of the scrubbing liquid and also the reaction speed are therefore higher. In very fast chemical absorption processes, the absorption capacity is principally determined by the extent of the boundary layer gas/liquid.
The choice of which scrubbing liquids are used to achieve the optimum effectiveness depends on the contaminant. The absorption scrubbers are either spray scrubbers (jet scrubbers) or packed tower scrubbers. They can be constructed in horizontal or vertical design.
PlasmaAir AG has vertical packed tower scrubbers as the standard design. Each scrubber and each exhaust gas system is designed to suit the process.