Electrochemical method for sulphur dioxide removal from flue gases: Application on sulphuric acid plant in Tunisia

This article presents an electrochemical method for sulphur dioxide removal; the idea consists to couple the phenomenon of electrolysis upstream to the sulphuric acid plant. Otherwise, this proposition consists in modifying the hybrid cycle Westinghouse by the elimination of the sulphuric acid decomposition stage, which corresponds to 61% of the energy distribution of this cycle. The step of the decomposition is replaced by the exploitation of the quantity of sulphur dioxide emissions SO2 stemming from the process of sulphuric acid H2SO4 production. The industrial complex of Gabès in South Tunisia is selected to be the case study complex. In fact, most industries are chemical oriented, the fast growing numbers of H2SO4 factories have resulted in fairly serious air pollution, especially sulphur dioxide SO2 pollution. To confirm the efficiency of this process, a mass balance study was made on the sulphuric acid plant, which used a double contact/double absorption process; this study demonstrates that this new method can treat 8 t d−1 of sulphur dioxide, recover 12 t d−1 of sulphuric acid of title 50% and produce 6889 m3 d−1 of the hydrogen. This idea can achieve economical and environmental benefits. It is concluded that the usage of this electrochemical process can significantly reduce the SO2 air pollution in Gabès (South Tunisia) by the elimination of 46.94 t d−1 of SO2. The results obtained are ambitious for future application of the new process, which can succeed in the realisation of 3.92 million dollars of gain every day.