Introduction to Chemical Engineering-I

A: Starting with valve stroking can hide a closed manual block and gives a false sense of readiness, checking PLC scaling assumes the field hardware is already safe and aligned, and bumping the motor before physical line verification risks deadheading or reverse flow, while walking the line first prevents basic but damaging configuration errors.

A: Cutting hot-side flow first masks the root cause and disrupts upstream balance, raising inlet temperature increases thermal stress and worsens the deviation, and forcing flow through a fouled exchanger raises pressure drop, while reduced coolant flow directly lowers U·A effectiveness and must be corrected at the source.

A: Half a kilowatt ignores the flow term and underestimates shaft work, one kilowatt drops either efficiency or unit conversion and lands low, ten kilowatts assumes extreme inefficiency not seen in small pumps, while ρgQH gives about 1.6 kW hydraulic and scales to a few kilowatts with losses.

A: Less reflux does not improve mass transfer driving force, reboiler duty does not self-correct without control action, and shorter residence time usually hurts contacting, while reflux provides internal liquid that washes heavy components back down.