Exhaust air purification in foundries

In foundries, different steel grades are melted in high-temperature furnaces and then poured into molds consisting of sand and a binder. When the molds are created in so-called core shooters, VOCs are generated during the pressing process, the main components of which are amines and formaldehyde. This exhaust air is extracted above the core shooters and released into the exhaust air at room temperature.

Energy consumption in foundries is heavily dependent on the energy used by the exhaust and supply air systems. High energy consumption also always means high production costs as well as high CO2 emissions.

The operation of core shooters is discontinuous. Thus, exhaust air purification is required that responds in the short term and increases the overall emissions of the company as little as possible.

Systems using UVC technology are used to clean the exhaust air from this sub-process of foundry technology. Plants have already been built for this purpose at Mercedes Benz in Mannheim.

When dimensioning the plants, particular attention should be paid to knowing the solvents used in the binders for the core shooters.

In addition, despite the reference MB tests should be performed to account for the different degradation mechanisms of the different amine components.

The VOCs are determined with an FID and the formaldehyde is determined wet-chemically according to a DIN method.

The exhaust air during the casting process consists mainly of the ambient air and a CO/CO2 mixture. This waste heat can be used as a heat source for energy recovery with an air-to-air heat exchanger.

As a provider of complete solutions, oxytec offers energy-saving exhaust air purification systems that are individually adapted to the company’s requirements. Compared to other established processes, oxytec systems enable energy savings of up to 85 %.