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Sludge Cryogenic Chamber Drying Machine combines vacuum freezing technology and realizes efficient sludge dehydration in a low-temperature environment through the synergistic effect of the three stages of "freezing-sublimation-capture". Its core principle is to use the ice crystal sublimation effect and the thermodynamic characteristics of the vacuum environment to break through the temperature limit of traditional thermal drying, avoid organic matter damage, and achieve a leap in dehydration rate.
1. Core steps and physical mechanisms of technical implementation
Pre-freezing stage: ice crystal network construction
Low-temperature solidification: sludge is quickly frozen in a low-temperature environment of -40℃ to -50℃, and the water forms an evenly distributed ice crystal network. This process requires precise control of the cooling rate to avoid excessive ice crystals from destroying the sludge structure.
Triple point breakthrough: The triple point temperature of water is 0.01℃/611.73 Pa. Through ultra-low temperature freezing, it is ensured that the free water and part of the bound water in the sludge are completely converted into solid ice.
Vacuum sublimation stage: direct gasification of solid water
Vacuum environment control: The system is evacuated to 10-50 Pa, at which time the saturated vapor pressure of ice is significantly increased. By maintaining a low-pressure environment, ice crystals can be sublimated directly into water vapor without liquid transition, avoiding sludge rewetting and agglomeration.
Energy supply optimization: In a high-temperature vacuum drying chamber, the latent heat required for ice crystal sublimation is provided by filter plate heating or microwave assistance to accelerate water migration.
Water vapor capture and separation
Cold trap condensation: The sublimated water vapor recondenses into ice on the surface of the cold trap at -50°C, and water is recovered through periodic defrosting, with a condensation efficiency of more than 95%.
Tail gas purification: The residual gas is treated by activated carbon adsorption or catalytic oxidation to eliminate volatile organic compounds (VOCs) and odors to meet environmental emission standards
2. Key technical parameters and efficiency improvement strategies
| Parameter Category | Typical range | Optimization goals |
| Freezing Temperature | -40℃ to -50℃ | Prevent ice crystal coarsening and maintain porous structure |
| Vacuum pressure | 10-50 Pa | Lower boiling point and promote ice crystal sublimation rate |
| Heating medium temperature | 70-90℃ (hot water or hot oil) | Reduce heat source grade requirements and improve energy utilization |
| Drying time | 4-12 hours (adjusted according to the amount of sludge) | Balance efficiency and energy consumption to avoid over-drying |
| Final moisture content | ≤10% | Meet landfill/incineration standards and achieve resource utilization |
3. Technical advantages and industry application verification
Organic matter retention and safety
Low temperature environment avoids protein denaturation and oil oxidation, which is particularly suitable for oily sludge and biomass sludge treatment.
Fully enclosed negative pressure operation eliminates the risk of dust explosion, and the heating medium uses hot water below 90°C to avoid the hidden danger of high-pressure steam leakage.
Environmental protection and economy
Zero chemical addition: only PAM flocculant is required to avoid sludge increment caused by lime/iron salt addition.
Energy recycling: Using waste heat from sewage treatment plants or industrial waste heat as heat source, the comprehensive energy consumption is only 30% of hot air drying
