I. Pressure Drop Is the "Blood Pressure" of the Heat Exchanger
Abnormal pressure drop rise means the flow channel is occupied. It often shares the same source as efficiency drop, but pressure drop is the more sensitive leading indicator—before it clogs enough to affect heat transfer, the current rises first.
II. Three Diagnostic Steps
- Step 1: Measure total pressure drop. Compare with design value; a rise above 20% warrants inspection;
- Step 2: Measure by segment. Add measurement points at heat exchanger inlet/outlet and between passes to lock down which segment rose;
- Step 3: Judge the pattern. Uniform small rise across the line = general ash accumulation; sudden rise in one segment = local blockage/foreign object.
III. Common Sources
| Phenomenon | Cause | Treatment |
|---|---|---|
| Uniform gas-side rise | Dust deposition, dirty filter | Purge, replace filter (online possible) |
| Water-side rise | Scaling, biological slime | Chemical/physical cleaning (mostly shutdown) |
| Sudden single-pass rise | Foreign object, plate deformation | Shutdown disassembly inspection |
IV. Treatment Boundaries
- Online: Back-blow, online brushing, filter replacement, no production stoppage;
- Shutdown required: Plate disassembly high-pressure water, chemical soaking, scheduled in maintenance windows;
- Prevention: Include pressure drop in daily inspection, set alarm threshold, don't wait for fan trip.
Treat pressure drop like blood pressure: measure daily, treat early, and the heat exchanger's life and efficiency both last longer.