Combined dry and wet flue gas purification system for separating off HF, HCl, SO3, SO2, NOx and dust

摘要

Process for the simultaneous separation of HCl, HF, SO2, dusts, heavy metals and NOx from flue gases preferably downstream of refuse incineration plants, characterised in that the high amounts of dust are first transferred, preferably by a gravity separator (cyclone) to a follow-up cloth filter, this being impinged by substoichiometric amounts of additives preferably to bind HF and HCl by hydrated lime, but the stoichiometric ratio for HCl and HF separation being fed via appropriate additives such as hydrated lime and the exhaust gas freed in the filter from dust, heavy metals, HCl and HF being fed together with the residual amount of SO2 and NOx to a downstream alkaline simultaneous wet scrubber which is operated with EDTA- and/or NTA-complex compounds and appropriate reducing agents to simultaneously separate off SO2 and NOx. The flue gases purified in this manner are transferred for delivery to the heat exchanger arranged downstream of the boiler or directly to the stack.