CO2 Heat Pump for Sewage Sludge Belt Dryer Boost Up The COP by 50%

The CO2 heat pump is used to increase the COP (Coefficient of Performance) of the sewage sludge belt dryer by 50%.

Thermal drying methods can be categorized into low-temperature drying (below 100 °C) and high-temperature drying (above 120°C). The heat pump sludge dryer operates at a drying temperature of 45-50°C (the temperature of the incoming dehumidification stream), while the blowing-in temperature ranges from 60-80°C (at the bottom layer).

This project utilizes a closed cabinet dehumidification CO2 heat pump drying system with a belt-type design. It does not require additional energy sources such as steam, thermal-conduction oil, or hot-blast air. Additionally, there is no need for tail gas treatment. The dryer effectively dehumidifies the sludge through hot-air recycling, condensing, dehumidifying, and drying processes. The evaporation of the sludge moisture generates latent heat, which is then used for vapor condensation.

The CO2 heat pump outperforms traditional R134a units in sludge dryers due to the significant temperature difference between the incoming stream and blowing temperature. This results in a 50% energy savings.

CO2 is a natural refrigerant with an ODP (Ozone Depletion Potential) of 0 and a GWP (Global Warming Potential) of 1. Therefore, there are no environmental regulations associated with its use.