Activated carbon as a viable alternative to thermal incineration
Suppliers to the automotive industry have to meet very strict conditions. For example, when coating components, it is essential that the air quality in the spraying booth is at a certain standard. A German company was at a loss what do when it appeared that a potential new investment could not possibly be ready in time to comply with the regulations. Fortunately for them activated carbon is providing a temporary, and perhaps even definitive, relief.
A manufacturer of small plastic parts for the automotive sector is responsible for the coating of these components. The coating is done in a spray booth where air treatment is essential because of the inevitable ‘overspray’. To comply with regulations, the German authorities had required the company to have a brand new installation for good air quality by New Year 2019. Because of the long delivery time of a thermal combustion system, management realised that this would be impossible. Moreover, such a new installation is a considerable investment, since it has to treat a flow rate of 35,000 m³ per hour.
Full-scale test installation
The company had to look for an interim solution anyway and contacted Desotec. An on-site inspection showed that an activated carbon installation could even be a relevant permanent solution, as the spraying process would from then on take place in two shifts (instead of three). Moreover, an activated carbon installation does not require a heavy investment, but falls under the operational costs. In order to carefully weigh the pros and cons, the company decided to temporarily install a full scale test installation.
The heart of this test installation is the mobile activated carbon filter Aircon H, with an activated carbon volume of 6 tons. In addition, the system consists of a fan with silencer (to avoid noise pollution) and the Inerti-Box safety system, which avoids the formation of hotspots. The advantage of this rental solution is that it can be used immediately thanks to the ‘plug & play’ principle, and that it was unnecessary for the installation to build certain foundations, which is required for thermal combustion. Should the customer decide that activated carbon does indeed appear to be the right solution, an Aircon V-XL filter is the ideal system. This filter has a larger activated carbon volume (11 tons) and allows a very smooth changeover once the activated carbon filter is saturated.
The customer also felt encouraged by the German authorities to look for an alternative solution. Germany is working hard to update the TA Luft regulations, transposing the European directives on air emissions into national law. Companies are advised to focus strongly on the Best Available Techniques. Activated carbon filtration makes it easier to comply with certain lower limit values (e.g. for benzene) and is not influenced by parameters such as dust and NOx emissions.
Activated carbon filtration technology has already proven itself extensively in the automotive industry and the paint and coating world. The German supplier will test the Aircon H filter over the next three months and will provide the government with the PiD-sensor’s measurement via logging. Undoubtedly the company will then make the right decision for the future treatment of air in the spray booths.
At DESOTEC’s facilities, all used carbon is analysed so the right measures can be taken for handling and removing the saturated carbon out of the mobile filters. All molecules that were adsorbed on the activated carbon at the customers’ site, are desorbed inside DESOTEC’s reactivation furnaces. These contaminants are then fully destroyed, in accordance with National and European legislation, by an incineration and neutralisation setup. The entire installation and it's emissions are under continuous on-line monitoring, which guarantees that only harmless water vapour is seen exiting the chimney.