Alternative fuels

Alternative fuels or Refuse Derived Fuels (RDF) are the end product of material processing plants. Commercial and municipal waste passes through a multi-stage comminution and preparation process here. The final grain size of the RDF is determined by the shredder in the final processing stage.

The fibrous-flaky particle shape of RDF has a negative effect on the flow properties if large forces, and therefore internal stresses, are acting on the material.

The main material properties can be summarized as follows:
Grain size » The coarser the particle, the poorer the flow
Grain shape » The more irregular the particle, the poorer the flow
Bulk density » The lighter the particle, the poorer the flow
Moisture » The moister the particle, the poorer the flow
Grease content » The greasier and stickier the particle, the poorer the flow

Below is an example of a typical material specification for RDF:
Bulk material: Waste, shredded
Bulk density: 0.1–0.5 t/m³
Grain size: 0–60 mm, partially 1–3% to 100 mm
Fines: Max. 2–3% < 300 µm
Grain shape: Two-dimensional, granular
Ash content: Max. 15%
Inert materials: Max. 5%
Ferrous and NF metals: Max. 0.5%
Grain size of metal parts: Max. 40 mm
Moisture: Max. 20%
Temperature: Max. 80°C
Flow properties: Moderate to low viscosity, bridge-forming
The following acronyms for alternative fuels are frequently used in specifications and other documents:
BRAM Brennstoff aus Müll (waste-derived fuel)
BPG Brennstoff aus produktionsspezifischen Gewerbeabfällen (fuels derived from production-specific industrial waste)
CDR Combustibile Derivato dai Rifiuti (refuse-derived fuel)
EBS Ersatzbrennstoff (substitute fuel)
EWAB Energy from Waste and Biomass
Fluff Fluffy alternative fuels
Flock Paper industry waste, rejects
OTS Organische Trockensubstanz (organic dry substance)
RDF Refuse Derived Fuel
RESH / ASR Residual shredder materials / Automotive Shredder Residue
SBS Sekundärbrennstoff (secondary fuel)
SLF Shredder Light Fraction