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

Chapter 44.4.8 Wet catalysis processDescriptionWet SO 2 gases (e.g. from the burning of H 2 S gases or from the catalytic conversion of H 2 Sgases) are directly supplied into the contact tower without previous drying. SO 3 formed by thecatalytic conversion immediately reacts with the moisture of the gases, thereby formingsulphuric acid. The sulphuric acid is condensed in a condenser installed after the contact tower.Process variants enable an improved condensation and the production of concentrated acid, forexample:• the Concat process is designed to produce H 2 SO 4 of higher concentrations from gases with alow SO 2 content. The formed H 2 SO 4 is condensed in two steps, a high temperature venturicondenser (this yields 93 % H 2 SO 4 ) and a condenser tower (this yields 70 – 80 % H 2 SO 4 )• the Topsøe WSA process is designed to reduce the formation of H 2 SO 4 mist. After theconversion of SO 2 into SO 3 , the gases are condensed in a falling film evaporator with glasspipes. The formation of mists is prevented by precise temperature control.AirHeatexchangeH 2OLean gasSteamdrumHot airSulphurFuelBurnerWasteheatboilerEmissionto airH 2O 2Rich gas1SteamScrubber2CondenserAirH 2SO 4ProductH 2SO 4Figure 4.14: Example for a wet catalysis processLenzing AG after expansion[63, Laursen, 2005]Achieved environmental benefitsTable 4.15 shows examples for the application of wet catalysis processes.• enables the conversion of the wet SO 2 gases• emissions from the Concat process: