Harden offers refuse derived fuels(RDF) shredding and recycling system. The solutions enable to process municiple solid waste to RDF. Substitute fuels/alternative fuels come from the high calorific value part of mix waste generated by city daily metabolism, mainly composed plastic, paper and wood chips. The most important influence for of RDF burning is content of the wet part(orangic materials). Nomarlly a machinical or manual sorting is required for RDF production. A system mostly refers to the process flow as below:
1. Primary shredding.
A primary shredder can break bulk waste and packed waste.
2. Waste separating.
a. ferrous separating by belt magnetic separator.
b. hexagonal screen for size separating.
c. Air separating for under-screen marterials.
d. The marterials sorted and conveyed by air has high calorific value and mainly suit to producing RDF.
e. The marterials heavier need further separating processes. A part of them could be RDF.
f. Nonferrous metals separating(optional).
3. Fine shredding.
Single shaft shredders or dual-single rotor shredders acts as a secondary shredder.
Substitute fuels –
Substitute fuels for incineration, used in cement plant calciners or power plants for energy recovery,
If it`s requreid the watse with <80mm partile size, a single shaft shredder is suitable.
Approximately 15-18 mJ/kg of calorific value by this part of waste.
A granulator or dual-single rotor shredders can reach a particle size with <30mm which ideally suited for injection furnaces and incineration in cement rotary kilns.It has a calorific value of at least 18-22 mJ/kg.
4. Further processing.
There are two kind materials for with different recovering method.
Composting or fermentation –
Composting or fermentation for the waste under-screen. Most of this part is orangic waste. Some of
the applications need dewatering by squeezing machine for qucik fermentation.
A RDF extruder can compact high calorific value waste into briquettes convinent for transport and burning for incinerations. Also this prossing will dry the materals as well resulting a high calorific value with 22-48 mJ/kg.