Since the mid-1990s, we have been using catalytic oxidation as an air purification technique in various situations depending on the nature and severity of the vapour flows that need to be purified. Traditional combustion techniques oxidise the vapour flows at temperatures of around 800 to 900 °C. With catalytic oxidation the vapours are oxidised by a catalyst at lower temperatures, around 400 to 500 °C. This has the advantage that less energy is required due to the heat exchange between incoming and outgoing vapour flows leading to an auto-thermal oxidation process more quickly. Catalytic oxidation units are often referred to as catalytic oxidisers or simply CatOxs.
When chlorinated hydrocarbons are oxidised, the oxidation at low temperature also means that there is no risk of dioxin formation. When chlorinated hydrocarbons are treated with a CatOx, the hydrochloric acid that is released has to be neutralised by means of a quencher/scrubbing unit. If there are greatly fluctuating peaks in the incoming vapour flows it is advisable to fit a peak shaver or ‘Glätung’ upstream of the CatOx. This can be in the form of a zeolite filter, activated carbon filter or a scrubber with washing oil.
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