Health, Safety & Environment (HSE) Fundamentals

A: This choice explains why carryover appears only at turndown by tying momentum criteria to the superseded standard and inlet hydraulics. The demister deadband would cause carryover across the load range, not only at low liquid rates. Nozzle elevation errors are flow‑independent once level is controlled. Foaming would show pressure drop increase and unstable levels, which aren't observed.

A: This mechanism fits CO₂ presence with intermittent oxygen, explaining rapid localized attack in wet service. SSC needs tensile stress and H₂S activity that isn't stated. Erosion‑corrosion would align with velocity hot spots and wall thinning rather than pits. Graphitization is a cast iron issue, not carbon steel spools.

A: Lengthening the cycle compensates for reduced driving force without stressing the bed. Pushing more flow shortens contact time and worsens breakthrough. Cutting purge raises impurity loading in the bed over successive cycles. A bed swap doesn't address the pressure‑dependent equilibrium.

A: This flow rate clears the stated volume within minutes when you back‑calculate from Bernoulli with typical loss factors. The smaller rates underestimate velocity for a short, flooded drain. The largest value ignores head limitation and friction. The lowest figure assumes restrictive valves that aren't in the scenario.