Environmental Engineering Reference
In-Depth Information
range from 29 kWh/t
MSW
(Lombardi et al., 2007) and 48 kWh/t
MSW
(Lombardi et al., 2006) -
dependant on the type pre-treatment - of about 38,5 kWh/t
MSW
was assumed. Consequently
the performance indicators related to energy are modified as reported in table 16.
Table 16. Energy performance indicators, considering the pre-treatment consumptions.
MSW-WtE
CF-WtE
CF-GAS
CF-PYR
Waste mass flow rate [kg waste/h]
14.344
9.537
9.537
9.537
LHV [kJ/kg waste]
10.127
12.201
12.201
12.201
Entering power [kW]
40.350
32.322
32.322
32.322
Net power output [kW]
8.896
7.367
5.273
9.447
Specific pre-treatment consumptions
[kWh/t
MSW
]
-
38,5
38,5
38,5
Pre-treatment consumption [kW]
-
552
552
552
Net power output considering pre-
treatment consumption [kW]
8.896
6.815
4.721
8.895
Efficiency [%]
22
21
15
28
Results in table 15 and 16 show that the efficiency of WtE applied to MSW or
combustible fraction is quite similar, but the amount of recovered energy is higher in MWS
WtE. Gasification of combustible fraction with energy recovery of syngas in steam cycle
offers a lower efficiency and lower amount of recovered energy with respect to WtE in
general. On the contrary, from a theoretical point of view, the combustible fraction pyrolysis,
with syngas energy recovery in engine, leads to a higher efficiency with respect to the other
considered systems.
Comparison of Integrated Energy Recovery Systems
The possibility of combining the thermo-chemical treatments for the combustible fraction
and the biological treatment for the humid fraction gave the possibility of composing four
integrated scenarios for the processing of MSW, as shown in figure 6. Scenario I is the direct
MSW combustion in WtE. In scenario II, MSW is mechanically sorted: the combustible
fraction (CF) is sent to WtE, while the humid fraction (HF) is sent to anaerobic digestion with
biogas energy recovery in engine. In scenario III, MSW is mechanically sorted: the
combustible fraction (CF) is sent to gasification with syngas energy recovery in a steam
cycle, while the humid fraction (HF) is sent to anaerobic digestion with biogas energy
recovery in engine. In scenario IV, MSW is mechanically sorted: the combustible fraction
(CF) is sent to pyrolysis with syngas energy recovery in engine, while the humid fraction
(HF) is sent to anaerobic digestion with biogas energy recovery in engine. Results for the
compared scenarios are reported in table 17.
