Simulation on deacidification performance of waste incinerator flue gas by rotating spray drying

Highlights: • Models of mass transfer and chemical reactions in deacidification tower are built. • About 60% of the removal amount of SO₂ and 90% of HCl are absorbed in upper tower. • Slurry drops completely evaporate in 5 s after entering deacidification tower. • Performance rises with increasing SR and water spray rate, decreasing gas speed and drop size. • Suggest the gas inlet speed of 7.1 m/s, drop size of 70 μm, water spray rate of 600 L/h. The models describing the mass transfer and chemical reaction of flue-gas−slurry drops in the deacidification tower of waste incineration plants are established. The internal dynamics are simulated and the effects of flue-gas inlet velocity, stoichiometric ratio, drop size and water spray rate, on deacidification performance, are evaluated. Results show that simulated desulphurisation and dechlorination rates are 58.97% and 99.99% and the removal rate of HCl is greater than SO₂. A high-temperature zone is found in the upper part of central axis, whereas low-temperature zones are observed at the right wall and bottom. Flow field is characterized with complex recirculation zones, wherein the recirculation zone emerged on the upper-right entrains a small part of drops towards the right wall. Approximately 60% of the total removal amount of SO₂ and 90% of HCl are absorbed in the upper part. Slurry drops completely evaporate in 5 s after entering the deacidification tower. The deacidification performance is improved with the increase in stoichiometric ratio and water spray rate, as well as the decrease in inlet gas velocity and drop size. Excellent deacidification performance is expected under flue-gas inlet velocity of 7.1 m/s, drop size of 50–70 μm, and water spray rate of 600 L/h.