Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 44.4.22 Tail gas scrubbing with H 2 O 2DescriptionSO 2 can also be converted to SO 3 through oxidation with H 2 O 2 or H 2 SO 5 . The conversion rate isabove 99 %. However, using an H 2 O 2 process instead of conventional single or double contactprocesses is not economically viable because of the raw material costs. Still, H 2 O 2 orelectrochemically generated H 2 SO 5 are applied as the scrubbing medium in order to recover SO 2from tail gases. The scrubbing yields H 2 SO 4 which can be recycled to the absorption stage of theH 2 SO 4 plant. Hence, this tail gas treatment does not create an additional waste stream or any byproducts.Achieved environmental benefits• SO 2 removal efficiencies of 98 % [57, Austrian UBA, 2001]• achievable emission level: 60 mg/Nm 3 [59, Outukumpu, 2005].Table 4.22 shows some example plants, the applied conversion type, and, where available, theachieved SO 2 levels.Example plantConversion typeSO 2 level in mg/Nm 3Tail gas Emission EfficiencyDegussa, Wesseling Double contact 1100 8 99 %Lenzing AG Wet catalysis process 2000 170 91.5 %Kemira Kemi, HelsingborgNewmont Gold, USCPM, BrazilDouble contact with5 th catalyst bedDouble contactDouble contact250 30 88 %Table 4.22: Achieved SO 2 levels by scrubbing with H 2 O 2Cross-media effectsChemicals and energy consumption.Operational dataNo specific information provided.ApplicabilityGenerally applicable.Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers 207