Heat Transfer_Crash Course for Campus Placement Interviews for Chemical Engineering

A: The hard boundary is that fouling degrades h on the order of weeks, not years. Even clean cooling water shows early biofilm and particulate deposition that collapses U well before any thickness loss or pressure issue shows up, which is why standards force margin up front during thermal design rather than letting operations absorb it later.

A: The telling threshold is unchanged ΔP. Maldistribution or valve issues would move pressure or flow signals. Fouling quietly eats thermal performance first, shrinking temperature approach while hydraulics look healthy, which is why trend analysis flags it before alarms do.

A: The number that matters is solids loading, not duty. High fouling services punish narrow passages. A removable bundle gives mechanical cleaning options and predictable derating, which is defensible under audit when trends are already drifting the wrong way.

A: MAWP and pressure integrity are the gating thresholds. Mechanical soundness comes before chasing thermal numbers, because a leak or tube failure under audit is non-recoverable, while early thermal checks are indicative only.