WSA, the Resilient Solution to Fluctuating Lean SO₂ Gases

This chapter delves into the challenges posed by lean and fluctuating SO2 gases in the copper industry, particularly in the context of tightening emission regulations. It explores traditional treatment methods and their limitations, such as scrubbing and amine enrichment, which either produce low-value by-products or incur high costs. The text introduces the Wet Gas Sulfuric Acid (WSA) process as a resilient solution, capable of efficiently capturing sulfur from low-concentration gases and operating autothermally, even with feed gases containing as little as 1.7%v SO2. The WSA process is detailed in three main steps: preheating, SO2 conversion, and H2SO4 condensation, with a focus on its ability to capture and reuse heat, enhancing energy efficiency. Industrial examples from South Africa and Chile demonstrate the practical benefits and economic advantages of the WSA process. Recent advancements, such as the integration of direct gas/gas heat exchange and optimization of recycle flows, further improve the process's stability and efficiency. The conclusion emphasizes the WSA process's role in supporting the copper industry's sustainability goals by reducing greenhouse gas emissions and increasing circularity.