Agglomeration and Deposition Behavior of Solid Recovered Fuel

Waste-derived fuels,
such as solid recovered fuel (SRF), are increasingly
being used in, e.g., the cement industry as a means to reduce cost.
The inhomogeneous nature of SRF makes it difficult to combust, and
many problems may arise within, e.g., combustion control, feeding
of fuel, deposit formation, or accumulation of impurities. The combustion
of polyethylene (PE), polypropylene (PP), polyethylene terephthalate
(PET), wood, and SRF were studied in a rotary drum furnace. The combustion
was recorded on a camera (60 frames per second), so that any agglomeration
or deposition of fuel or ash could be monitored. PE and PP pose no
significant risk of forming deposits in a combustion environment (T > 800 °C) as a result of a rapid devolatilization,
while PET may cause deposits as a result of a sticky char residue.
The deposition tendency of the investigated SRF is low, and it may
be managed by a careful combustion control. The ash from SRF or wood
does not pose a significant risk of melting and deposits at temperatures
up to 1000 °C, but the presence of glass impurities in some SRF
may limit operation temperatures to 900 °C as a result of ash
melting.