The separation of the main combustible components of municipal solid waste through a dry step-wise process

• A step-wise process was developed to separate the combustible components of municipal solid waste.
• Elutriation technique was exploited to separate fiber and soft plastic materials.
• A proper medium was used to make density segregation possible in a fluidized bed.
• Non-combustible species and hard plastic were separated based on density segregation.
• Segregation kinetic was determined to ensure the feasibility of process scale-up.

Tailoring the solid waste-based fuel composition is essential to improve the combustion efficiency and control the resulting emissions. In the present study, a dry step-wise process has been developed in a pilot-scale setup to recover the main combustible elements of shredded bulky waste (SBW) consisting of 72% fiber, 12% soft plastic and 8% hard plastic. For this purpose, the SBW is initially elutriated to enhance the processability of the feedstock and separate its lightest components. Elutriation of SBW at Ue = 1.5 m/s for 15 min could result in the effective separation of light components, i.e., fiber and soft plastic. These components are then separated from each other in a second elutriation column at Ue = 0.2 m/s for 2–3 min. In the presence of a proper fluidization medium, the non-elutriated fraction of the SBW is further separated into non-combustible, undesirable combustible components and hard plastic through two consecutive steps. Size and density of the bed medium as well as the initial configuration of the bed inventory are the parameters governing the recovery and purity percentage of the fluidization steps.

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