Pretreatment of recycled paper sludge with a novel high-velocity pilot cyclone: Effect of process parameters on convective drying efficiency

摘要

To address the growing need for economically viable sludge processing technologies and associated resource recovery, a novel convective high-velocity pilot cyclone was set-up at the Swedish University of Agricultural Sciences in Umea, Sweden. In essence this process entails feeding (≤900 kg h~(-1)) a material to a heated high-velocity air flow (approx. 13 × 10~3 m~3 h~(-1)) allowing moisture removal at low temperatures. This equipment is expected to improve drying of challenging industrial sludge materials when used as a pretreatment method prior to further processing. Modeling results based on an experimental campaign on recycled paper mill sludge indicated that efficient drying with a specific energy consumption of ≤1-1.2 kWh kg~(-1) H_2O can be achieved with inlet air temperature levels ≥40 ℃ coupled with respective feeding capacity of ≤750 kg h~(-1).