The Core Reasons Why Microcrystalline Salt Blockages in Plate-Type Condensers Are Difficult to Clear Through Conventional Water Flushing

1. The flow channel structure of the plates is inherently unsuitable for water flushing

Plate-type condensers feature narrow flow channels, crisscrossing corrugations, and numerous dead corners. During flushing, the water flow takes a straight-line shortcut, resulting in extremely low flow velocities in areas with heavy microcrystalline deposits, where there is virtually no effective shear force for scouring;

Salt crystals become lodged in the corrugation grooves and the gaps at the plate contact points, so the water can only reach the surface layer and fails to dislodge deep-seated deposits.

2. Microcrystalline scale is a dense crystalline deposit, not loose sediment

The calcium and magnesium salts, as well as trace salt crystals, precipitated on the evaporation and condensation sides form hard, dense crystalline layers—not loose sediment. Fresh water provides only physical flushing action and lacks dissolving power; it cannot break the ionic bonds between crystals and can only wash away a minimal amount of surface dust.

3. Scale possesses an adhesive base that firmly anchors itself to the metal surface of the plates

During long-term operation, an extremely thin passivated scale base first forms on the inner walls of the plates. Microcrystals continuously grow and cross-link on this base, causing the crystals to adhere tightly to the metal. Wetting with room-temperature water cannot break the interfacial adhesive force, so the crystals will not detach in large chunks.

4. Low-temperature conditions of condensate result in extremely low solubility of salts

Conventional washing uses room-temperature water, but calcium and magnesium carbonates and sulfates have extremely poor solubility in cold water. Not only does the flushing process fail to dissolve existing scale, but the trace hardness ions carried by the water flow can cause new microcrystals to precipitate, leading to increasingly severe blockages with each wash.

5. Narrow plate gaps restrict water flow and turbulence intensity

The gaps in plate channels are typically only 2–6 mm wide; the standard flow rate of a water-washing pump cannot generate high turbulence. Without strong vortices or high shear forces to tear apart the crystal layers, gentle water flow alone cannot dislodge the hardened crystalline scale.

6. Alternating wet and dry cycles accelerate crystal solidification, rendering clean water ineffective

Before shutdown washing, scale on the plates undergoes repeated cycles of condensation and evaporation. This dehydrates and compacts the microcrystals, significantly increasing the hardness of the scale layer; clean water lacks the penetrating and softening effects needed to cause the scale layer to swell and loosen.

Additional Distinction: When Is Water Washing Effective?

Only sludge, colloids, and loose organic floating layers can be removed by water washing; inorganic salt microcrystalline scale must be treated with acid washing or chelation cleaning. This relies on chemical dissolution to break down the crystal structure, followed by high-flow rinsing to clear the blockage.