Soru

Before operators initiate the thermal cycling phase of a cryogenic distillation column, several preparatory milestones must be achieved. Technicians must first purge the auxiliary piping with dry nitrogen to eliminate residual moisture. Once moisture sensors confirm relative humidity falls below two percent, the primary refrigeration loop is engaged to pre-chill the condenser jacket. However, prior to lowering the condenser temperature below freezing, workers must calibrate the digital pressure transducers, but only after the secondary bypass valve has been manually locked. Following condenser chilling, the feed stock is introduced into the column base.

Based on the passage, which action must technicians complete immediately before calibrating the digital pressure transducers?