Heat exchangers and auxiliaries: identify the wrong statement regarding safety valves, heat-transfer media, tube routing, and loop seals.

Introduction / Context:Practical heat exchanger design includes not only thermal sizing, but also pressure integrity and operability details such as venting non-condensables, managing condensate, and routing high-pressure streams. Distinguishing correct practices from misconceptions is essential for safe operation.

Given Data / Assumptions:

• Typical shell-and-tube condenser or exchanger under industrial service.
• Presence of non-condensables (air) in condensers requires venting.
• Overpressure protection is a separate safety function.

Concept / Approach:Non-condensables are removed via vents, not safety valves. Safety valves relieve overpressure to protect equipment integrity. High-pressure fluids are commonly routed through tubes for safer containment and easier tube-side maintenance. Loop/U-seals in vertical condensers maintain a liquid seal to prevent sudden draining and potential vapor bypass.

Step-by-Step Solution:Evaluate (a): uses safety valves to remove non-condensables → incorrect; vents are used for this duty.Evaluate (b): high-temperature heating media include Dowtherm and liquid metals → correct.Evaluate (c): routing high-pressure stream through tubes → common and correct practice.Evaluate (d): loop seal preventing quick drain/air ingress → correct.

Verification / Alternative check:Piping and instrumentation diagrams (P&IDs) depict dedicated vents on condensers. Pressure relief devices are sized per code for credible overpressure scenarios, not for air removal.

Why Other Options Are Wrong (i.e., not the wrong statement):(b), (c), and (d) reflect standard industry practice.

Common Pitfalls:Confusing vent/bleed valves with pressure safety valves; misrouting high-pressure fluids through shells, complicating containment.

Final Answer:Safety valves are provided in heat exchangers for removal of non-condensables.