🔍 Key Concepts
• Identify what fluid is flowing in line 4 (seawater, brine, or distillate) and in which direction it moves when the plant is operating at sea.
• Determine which pump and heat exchangers/flash chambers are directly affected by line 4, using the legends for PU, HX, FC, OR, and MD.
• Think about what a fouled strainer does to flow and pressure: increased resistance, reduced flow, possible suction problems at the pump.
💭 Think About
• Trace the flow path starting at the pump that feeds line 4: if the strainer plugs, which downstream components will see less flow or no flow?
• Ask yourself which of the listed effects (loss of distillate, pump vapor bound, unstable temperature control, or no noticeable change) would most directly result from reduced flow in that particular line.
• Compare how the system is arranged for at-sea operation versus other modes: is line 4 essential in this mode, or is it bypassed/isolated so that a fouled strainer would have little effect?
✅ Before You Answer
• Verify from the diagram which valves around line 4 are open or should be open in at-sea operation; a closed valve means the line may not be in use.
• Confirm whether line 4 is on the seawater feed side, the brine overboard discharge, or the distillate product side – this will narrow which of the four outcomes is physically reasonable.
• Before choosing, check that your option matches both the hydraulic effect (what the strainer does to flow) and the location (what that part of the system actually controls).