Exhaust air purification of solvent-containing exhaust air in the chemical industry

Cause

The chemical industry for sealants and adhesives produces solvent-containing exhaust air of approx. 12,000 m³/h with pollutant concentrations of 300 to 700 mg/m³ from production areas and cleaning work. Due to the odour pollution for an adjacent residential area and the fluctuating pollutant concentration trends at a low level, the patented regenerative process uviblox® FOX, compared to thermal post-combustion, represents a cost-effective and safe alternative for the client.

Exhaust air purification system uviblox® FOX

The main flow of 12,000 m³/h polluted with VOCs (volatile organic compounds, mainly acetaldehyde, acetic acid, formaldehyde, aliphatic hydrocarbons) is alternately fed through two parallel adsorption stages. Here, the fluctuating VOC loads of 300-700 mg VOC/m³ are completely separated to < 50 mg C/m³ by adsorption using a suitable adsorbent. The outgoing exhaust air permanently meets the required clean air limit values.

Even before the adsorbent is exhausted, the system switches to a second parallel fresh adsorption stage. The first stage is regenerated in the regeneration circuit. Here, the pollutants are desorbed from the adsorbent and passed through a UV photo-oxidation stage and subsequent catalyst stage before returning to the adsorption stage.

Due to the energy input of the UV radiation, the circulating air heats up to operating temperatures that are required for the desorption and regeneration of the adsorbent as well as for the operation of the catalyst stage.

The process has very low operating costs, as no other costs are incurred apart from electricity. Considerable additional operating costs can be saved via heat recovery.