Simultaneous SO2 and NOx removal by employing an electrolytic process while taking account of the conductivity of the scrubbing solution

摘要

The main application P 3447425.0 describes a process for SO2 and NOx removal by using an electrolytic process. In order to be able to operate such a process economically, it is proposed according to the invention to employ a scrubbing liquid in the process, based on complexed iron(II) solution, whose conductivity is maintained between 70 and 100 mS/cm. In order to obtain this conductivity it is further proposed that the scrubbing liquid be set to a pH between 4.5 and 6.5. In addition, the scrubbing liquid is enriched with an Fe concentration of 5-6.5 g/l, the Fe(II) content, for a scrubbing efficiency above 90%, expediently being greater than 2 g/l scrubbing solution and, for a scrubbing efficiency of approximately 80% at less than 2 g/l scrubbing solution, the overall content of Fe(II) and Fe(III) being kept at 5-6.5 g/l. It was further found that a significant improvement of the conductivity can be achieved by employing carboxylic acids.