Environmental Engineering Reference
In-Depth Information
Table 1. Material composition and mass flow rate for MSW,
combustible fraction and humid fraction.
MSW
Combustible fraction
Humid fraction
Paper and cardboard
15,53%
21,59%
2,57%
Organic fraction
30,14%
19,84%
54,85%
Pruning scrap
8,74%
7,03%
13,02%
11,99%
1,43%
Plastics
8,63%
Metals
7,07%
5,17%
7,01%
Wood
4,46%
5,22%
2,95%
Glass
8,44%
5,56%
15,36%
Textiles
16,99%
23,61%
2,81%
14.344
9.536
4.649
Mass flow rate [kg/h]
LHV [kJ/kg]
10.127
12.201
3.647
On the basis of the assumed elemental composition and moisture content for each single
material fraction (table 2), whose results are coherent with literature values (Tchobanoglous
et al., 1993), the overall elemental composition and moisture content of each waste stream
(MWS, combustible fraction, humid fraction), were determined and results are reported in
table 3.
The elemental composition for each waste stream is required in the chemical and
thermodynamic models used for the mathematical simulation of the analysed processes.
Table 2. Assumed elemental composition and moisture
content for each material fraction
Carbon Hydrogen Oxygen Nitrogen Sulphur Inert
Moisture
Paper and cardboard
33,30%
3,30%
30,68%
0,08%
0,23%
7,43%
25,00%
Organic fraction
16,80%
2,24%
13,16%
0,91%
0,14%
1,75%
65,00%
Pruning scrap
25,03%
4,79%
11,06%
0,99%
0,11%
13,04%
45,00%
Plastics
66,98%
10,93%
10,74%
0,86%
0,86%
4,66%
5,00%
Metals
0,44%
0,53%
3,78%
0,09%
0,00%
83,16%
12,00%
Wood
39,60%
4,80%
34,16%
0,16%
0,08%
1,20%
20,00%
Glass
0,49%
0,10%
0,39%
0,10%
0,00%
96,92%
2,00%
Textiles
35,64%
5,85%
22,77%
5,04%
0,63%
20,07%
10,00%
Combustion with Energy Recovery
The most common route followed to realise energy recovery from waste is their direct
combustion associated with conventional energy recovery in a steam cycle. This is
conventionally addressed as a Waste-to-Energy (WtE) process. The WtE can be applied
directly to MSW or can be applied to the combustible fraction obtained by means of
mechanical sorting.
