New dynamic models for simulation of industrial SO2 oxidation reactors and wet gas sulfuric acid plants

• New dynamic model for SO2 oxidation reactors is proposed.
• Extensive comparison with experimental data.
• Good alignment between simulations and pilot- and industrial data.
• Full scale simulation of industrial wet gas sulfuric acid plants enabled.

Simulation of plant performance during start-up, shutdown, and changes in the feed for industrial sulfuric acid plants requires dynamic modeling of the complete plant. A dynamic tanks-in-series model has been set up for the SO2 oxidation reactor with accumulation terms accounting for absorption and desorption of SO3 in the catalyst melt, which can have significant effect on operation due to the large absorption capacity of the SO2 oxidation catalyst. Simulations are compared with pilot and industrial scale measurements, and good agreement is found for temperatures, SO2, and SO3 concentrations when flow rate, temperature, and composition of the feed are changed. A corresponding model for the transient operation of a sulfuric acid condenser has also been developed. Implementation of the models in a commercial dynamic simulator has enabled full closed-loop simulation of industrial SO2 oxidation reactors and complete WSA plants.