Yes, once activated carbon becomes saturated, it can cause reverse contamination of the condensate through both permeation desorption and solid carryover.

I. Adsorption Saturation: Organic exhaust gases directly permeate the adsorption layer.

Once the pores of the activated carbon are filled with alcohols, organic acids, complexing agents, and volatile additives, it loses its adsorption capacity.

Organic vapors generated by evaporation and trace heavy metal droplets are no longer retained; they pass directly through the carbon tank into the condenser, where they liquefy upon contact with the cold liquid and mix into the condensate, causing COD, organic matter, and trace heavy metal levels to exceed standards.

II. Negative pressure and warm operating conditions trigger desorption, causing accumulated pollutants to be released back into the system

The exhaust gas carries residual heat of 40–60°C, and the entire system operates under continuous negative pressure. The combination of high temperature and low pressure disrupts the adsorption equilibrium of the activated carbon:

Organic substances previously adsorbed within the carbon are desorbed and volatilized in large quantities, rushing into the condensation circuit with the gas flow.

At this point, the amount of pollutants released far exceeds that under conditions without activated carbon, and the degree of contamination in the condensate water increases significantly.

III. Carbon Layer Pulverization: Ultrafine Carbon Dust Enters the Condensation System with the Gas Stream

The carbon layer is subjected to prolonged erosion by high-velocity gas streams and alternating hot and cold temperatures, causing particles to break down into fine carbon dust;

Once saturated, the carbon structure becomes even more porous, making the carbon dust highly susceptible to being carried by the gas stream. It passes through the demister screen into the condenser, mixes with the condensate, turning the water black and turbid, and increasing its solids content.

When carbon powder enters the evaporator via the reclaimed water, it also adheres to spray nozzles and heat exchange plates, forming composite scale.

IV. Fermentation of Saturated Organic Matter Produces Foaming Impurities, Further Exacerbating Contamination from Carryover

The carbon bed accumulates large amounts of organic matter, which slowly decomposes within the sealed piping to produce small-molecule organic acids and surfactants;

When these foaming substances are recirculated into the evaporation chamber, foam levels surge dramatically, causing mist droplets to carry more salt-containing mother liquor into the condensate, which in turn increases the salt content.

V. Associated Chain Reaction Losses

Desorbed alcohols and organic acid vapors can also enter the vacuum pump, causing the pump oil to emulsify and oxidize, further deteriorating vacuum stability.