Combustion and decomposition of VOCs from shell moulds by regenerative thermal oxidiser

摘要

In the present work, the regenerative thermal oxidiser (RTO) with preheating and baking system was applied to treating volatile organic compounds (VOCs) discharged from the shell mould casting. As a result, it was found that the tar characterised by more than 523 K of high boiling point was formed by the shell mould casting. The Fourier transform infrared spectrometry analysis showed that the tar was composed of paraffin, zinc stearate and quartz. A part of the tar was deposited on the ceramic honeycombs in the heat exchanger. However, the tar can be almost completely removed by means of baking treatment at 623 K in the RTO. Regarding the decomposition of VOCs, it was found that the concentrations of all VOCs were reduced to less than 1 ppm. Further, 98% of offensive odour was removed by the treatment. Thus, it can be concluded that the RTO is suitable for decreasing VOCs from the shell mould casting in the foundry.