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

Chapter 44.4.3 Addition of a 5 th bed to a double contact processDescriptionBy retrofitting a double contact plant with a 5 th catalyst bed, a conversion rate of 99.9 % can beachieved and fluctuations of the inlet SO 2 concentration can be compensated. The retrofitting ofan existing contact plant with a 5 th bed is possible, if sufficient room is available. The 5 beddouble contact plant is realised as a 3+2 layout (3 catalyst beds prior to the intermediateabsorber).Achieved environmental benefitsNote: Conversion rates, tail gas SO 2 concentrations and specific SO 2 load in tail gases arecorrelated, see Figure 4.7, Figure 4.8 and Figure 4.9.• lower SO 2 emissions through higher conversion rates.Cross-media effectsHigher pressure drop and consequently slightly higher electricity consumption for compression.Operational dataNo specific information provided.ApplicabilityGenerally applicable for double contact plants, provided that sufficient room is available. At theHamburger Affinerie AG, the waste gases of a copper smelting process are used for sulphuricacid production (three lines). The third line of 1300 tonnes/day (installed in 1991), consists offive catalyst layers. Extra costs for the 5 th catalyst bed were about EUR 1000000. SO 2 emissionsof this double contact plant are 300 mg/Nm³ on average, corresponding to an averageconversion rate of 99.89 %.EconomicsFor cost calculations for retrofitting H 2 SO 4 plants, see Table 14.1.Driving force for implementationLower SO 2 emissions.References to literature and example plants[57, Austrian UBA, 2001, 58, TAK-S, 2003, 60, Windhager, 1993], Hamburger Affinerie AG,Atlantic Copper, Huelva, Rontealde S.A., Bilbao176 Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers