Refinery sour water stripper (NH₃ + H₂S)

The standard refinery sour water stripper: sour water carrying ammonia and hydrogen sulfide is steam-stripped in a 10-stage column, sending both overhead as sour gas and returning stripped water fit for reuse. Runs on the new sour-water weak-electrolyte package, which is what makes the result meaningful — ammonia and H₂S suppress each other's volatility (ammonia raises pH and holds sulfide down as HS⁻; H₂S lowers pH and holds ammonia down as NH₄⁺), and heat reverses both, which is precisely why a stripper works. The two removals come out asymmetric for the real reason: H₂S strips essentially completely while ammonia, five orders of magnitude more soluble, is the duty that sets the steam rate. Honesty note: this is the NH₃/H₂S system — real sour water often also carries CO₂, which competes for the ammonia and is out of scope for this package.