I. The physical structure of activated carbon itself makes it highly prone to clogging the pores of filter screens.

Powdered activated carbon particles are porous, irregularly shaped, and angular, with particle sizes typically in the micrometer range. They fit perfectly into the gaps between the metal wires of demister screens and at the intersections of the mesh.

Ordinary salt crystals are smooth, hard crystals that easily slide off when washed by airflow; activated carbon particles, however, have a high coefficient of friction. Once lodged in the gaps of the mesh weave, they become stuck and will not fall out on their own, gradually accumulating layer by layer to narrow the airflow channels in a short period of time.

II. Activated carbon adsorbs organic colloids and salt crystals, forming a composite filter cake that causes blockage (the core cause)

Wastewater naturally contains dyes, slurries, trace polymers, and salt microcrystals. Activated carbon’s extremely strong adsorption capacity simultaneously captures all these impurities:

Activated carbon adsorbs organic foaming substances, forming a sticky base that adheres firmly to the surface of the metal wires;

Salt crystals and suspended solids are adsorbed both inside and outside the pores of the activated carbon, forming a dense, airtight composite filter cake on the mesh surface;

Ordinary saline wastewater contains only single salt crystals, which are loose and easily blown away by airflow; the combination of activated carbon, organic matter, and salt crystals forms a plastic mud cake with extremely strong adhesion.

III. Foam acts as a transport medium, continuously delivering activated carbon to the demister screen

A small amount of activated carbon is suspended in the feed liquid; the fine foam generated by evaporation carries a large amount of carbon powder upward, all rushing toward the top demister screen:

After the foam breaks, the carbon powder settles directly onto the mesh layer;

The accumulation of carbon powder further traps foam and water vapor, creating a cycle where the system becomes increasingly prone to material buildup;

Without carbon powder, the foam carries only trace amounts of salt mist, resulting in a much longer interval between blockages.

IV. Activated carbon possesses hydrophobic and gas-loving properties, allowing it to remain in the gas-phase separation zone for extended periods

Activated carbon is hydrophobic and is not easily washed away by the recirculating liquid:

Normally, salt mist droplets contacting the mesh coalesce into a liquid film that flows back into the chamber, washing away surface salt crystals in the process;

Activated carbon powder is insoluble in water and difficult for the liquid phase to wet; once attached to the mesh surface, it does not flow back with the return liquid but continues to accumulate, gradually clogging the mesh layers from the surface to the deeper layers.

V. Accumulated carbon powder disrupts gas flow pathways; localized velocity spikes exacerbate clogging

Once local mesh pores become blocked, the steam flow is forced to pass through the remaining narrow channels at high speed. This high-velocity flow entrains more activated carbon particles, which violently impact the remaining mesh pores and embed deeper into the metal gaps, accelerating the clogging rate; soon, overall gas flow resistance surges and vacuum pressure drops.

VI. Comparison of Blockage Differences with Ordinary Salt-Containing Wastewater

Ordinary high-salt wastewater: Contains only smooth inorganic salt crystals; backflow can flush them away; long blockage cycles; loose scale layers;

Wastewater containing powdered activated carbon: Carbon particles become embedded in the mesh + adsorption of organic colloids forms a dense sludge cake; the liquid cannot flush or dislodge it; within days or even hours, the pressure drop across the demister screen increases and vacuum performance deteriorates.