China Nonferrous Metallurgy

The paper introduces the process principle, process flow, main equipment and operation of ionic liquid desulfurization system for acid making tail gas and flue gas. Green renewable ionic liquid aqueous solution, dominated by organic cation and inorganic anion with an addition of little activator and anti-oxidant can be used as a desulfurization adsorbent, which can realize selective adsorption and desorption of SO₂ in the flue gas. In view of the problems existing in the production and operation, such as equipment corrosion, system blockage, sodium sulfate crystallization,etc., the paper summarized a series of measures through continuous optimization and improvement of the process and equipment after years of production practice. The measures comprise anionic type exchange resin as the demineralized resin, imported resin with mixed 1m3 weak base anion specifically for dechlorination, addition of equipment such as diluted acid cooler and increase of heat exchange area, etc. The process is green, mature, reliable and stable, and the by-products can be recycled and discharged into the tail gas ρ(SSO₂)＜100mg/m³, realizing ultra-low emission of tail gas SO₂, with remarkable environmental and economic benefits.