Dilution of concentrated mineral acids (H₂SO₄, HCl, Nitric Acid (HNO₃), H₃PO₄) with water is highly exothermic and demands complete homogenisation to prevent hot spots.
Coefficient of Variation (CoV) ≤0.05 within 3D of mixer exit. Exotherm calculation required: H₂SO₄ dilution generates ~880 kJ/mol heat of dilution. Jacketed housing needed if temperature rise >30°C. Add acid to water — always add concentrated stream to dilute.
Preferred MOC: FRP or PVDF for dilute H₂SO₄ (<93%), HCl, and Nitric Acid (HNO₃). Carbon steel for conc. H₂SO₄ (>93%). PTFE-lined injection quill for concentrated acid contact.
Jacketed housing with cooling water for highly exothermic dilution duty. Injection: add acid to water flow — not water to acid. Temperature probe minimum 3D downstream. Safety: double-containment on injection line, pressure relief on concentrated acid side.